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Producing biomass briquettes from industrial solid wastes is a more environmentally friendly way to provide alternative energy and is essential for Ethiopia to satisfy its growing energy needs while also ensuring efficient waste management in the expansion of industrial parks. The main objective of this study is to produce biomass briquettes from a mixture of textile sludge and cotton residue using avocado peels as a binder. Textile solid waste, avocado peels, and sludge were dried, carbonized, and turned into powder to make briquettes. Briquettes made from the mixture of industrial sludge and cotton residue were combined in various ratios: 100:0, 90:10, 80:20, 70:30, 60:40, and 50:50 with the same amount of the binder. Briquettes were then made using a hand press mold followed by sun-drying for two weeks. The moisture content, calorific value, briquette density, and burning rate of biomass briquettes ranged from 5.03 to 8.04%, 11.19 to 17.2 MJ/kg, 0.21 to 0.41 g/cm3, and 2.92 to 8.75 g/min, respectively. The results revealed that the briquette produced from a 50:50 ratio of industrial sludge to cotton residue was the most efficient. The inclusion of avocado peels as a binder enhanced the briquette's binding and heating properties. Thus, the findings suggested that mixing various industrial solid wastes with fruit wastes could be an effective means of making sustainable biomass briquettes for domestic purposes. Additionally, it can also promote proper waste management and provide young people with employment prospects., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Expansive clays feature high compressibility and large swelling-shrinkage potential, which may cause significant damage to the infrastructures, including pavements. This study investigates the potential use of industrial waste ash generated from municipal solid waste incineration (MSWI) as a more sustainable treatment method to treat expansive soils compared to the use of conventional coal fly ash. A series of tests was conducted to study the mechanical, durability, and environmental performance of the MSWI fly ash in comparison with the coal fly ash. The study reveals that the compressive strength and resilient modulus of 20% MSWI fly ash treated sample increased to 0.86 MPa and 213 MPa respectively, depicting an increase of 150% and 240% of the control clay specimen. Results also indicate that MSWI treated expansive clay shows better performance during the soaked California bearing ratio (CBR) testings, moisture susceptibility and cyclic wetting–drying tests compared to coal fly ash treated samples. Microlevel investigations reveal that the influence of cation exchange is more decisive in the MSWI-treated clays due to the presence of higher Ca2+ ions, during the early stages, and the influence of hydration is stronger at the later stage of stabilisation. X-ray diffraction (XRD) results show that gismondine, albite, calcite, portlandite, andradite, and ettringite are the main crystalline phases formed during the stabilization. Heavy metal concentrations after the stabilisation are within the allowable limit defined by state regulations. Applying MSWI fly ash as a ground treatment for expansive clays can reduce the consumption of natural resources, promoting a "zero landfill" policy. [ABSTRACT FROM AUTHOR]

Highlights: Data analysis revealed that an appropriate amount of BPG can enhance the mechanical properties of cementitious materials, with compressive strength increasing by an average of 7–30%. The mechanical properties and underlying mechanisms of BPG-based cementitious materials were summarized. This study analyzed the mechanisms of the conversion and utilization of elements of impurities in BPG, as well as the solidification mechanisms of hazardous elements. The mechanisms of synergistic utilization between BPG and silica–alumina-based solid waste, as well as alkaline solid waste, are summarized, showcasing innovative waste management strategies. A sustainable solution for promoting the collaborative low-carbon development of various industrial solid wastes using BPG is proposed. Industrial byproduct gypsum (BPG) is a secondary product that is mainly composed of calcium sulfate discharged during industrial production. BPG primarily consists of desulfurized gypsum, phosphogypsum, and titanium gypsum, which account for 88% of the total BPG in China. The large-scale utilization of these three types of solid waste is crucial for the safe disposal of BPG. BPG contains various impurities and harmful elements, limiting its applications. The continuous accumulation of BPG poses a serious threat to the safety of the environment. Based on a literature review (2021–2023), it was found that 52% of BPG is used in the preparation of cementitious materials, and the addition of BPG results in an average improvement of 7–30% in the mechanical properties of cementitious materials. Moreover, BPG has a positive impact on the immobilization of hazardous elements in raw materials. Therefore, the utilization of BPG in cementitious materials is beneficial for its large-scale disposal. This study primarily reviews the effects and mechanisms of BPG on the mechanical properties of cementitious materials and the solidification of hazardous elements. Most importantly, the review reveals that BPG positively influences the hydration activity of silica–alumina-based solid waste (such as steel slag and blast furnace slag) and alkaline solid waste (such as carbide slag and red mud). This improves the proportion of solid waste in cement and reduces production costs and carbon emissions. Finally, this article summarizes and proposes the application of BPG in cementitious materials. The application of BPG + silica–alumina solid waste + alkaline solid-waste-based cementitious materials is expected to realize a new type of green ecological chain for the joint utilization of multiple industrial solid wastes and to promote the low-carbon sustainable development of industrial clusters. [ABSTRACT FROM AUTHOR]

Copyright of Industrial Minerals & Processing / Huagong Kuangwu yu Jiagong is the property of Industrial Minerals & Processing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The electrodes of industrial electrostatic precipitators degrade as a result of two phenomena: corrosion and erosion. The first is chemical degradation by highly reactive compounds formed during combustion, in particular, during the incineration of municipal or industrial wastes or high-sulfur coal. The degradation intensity of electrostatic precipitator electrodes depends on the chemical composition of the exhaust gasses. High concentrations of chlorides, fluorides, or sulfur in the exhaust gasses cause strong corrosion of the electrostatic precipitator elements. The second mechanism is the erosion caused by solid particles conveyed by the exhaust gas stream due to their collision with the electrodes. In this study, the analysis of the degradation of electrodes of an electrostatic precipitator downstream of an industrial waste incinerator was carried out. The industrial wastes of unknown sources were subjected to thermal degradation in a rotary kiln. The aim of this study was to provide fundamental knowledge about the mechanisms of electrode degradation located on the surface of discharge electrodes of electrostatic precipitators during the combustion of industrial wastes. [ABSTRACT FROM AUTHOR]

In most Brazilian municipalities, urban solid waste (USW) is disposed of in open dumps, with numerous sites now being closed, monitored, and rehabilitated. One location, the "old dump" area in the Portão municipality (southern Brazil), previously served as an irregular repository for USW and industrial solid waste (ISW). Its use continued until 1993 when it was closed for a natural remediation process. For this reason, this study aimed to assess groundwater quality in the Portão "old dump," employing physicochemical, microbiological, and toxicity quality indicators. The study's scope was extended to encompass the Portão Stream as well. Notably, the second collection campaign revealed elevated dissolved aluminum (Al3+), iron (Fe2+), and nitrate levels in all groundwater samples (from PZi wells, i = 1–6), with the PZ3 monitoring well experiencing the most pronounced impact. Further quality indicators, such as total phosphorus, thermotolerant coliforms, BOD5, as well as Al3+ and copper (Cu2+) levels in the second water collection campaign from Portão Stream, were classified as Class 4, suggesting that the water is suitable only for navigation and aesthetic purposes. Conductivity analysis identified Portão Stream as another impacted area. Moreover, during the second collection campaign, the study uncovered an escalation in micronuclei (MN) frequency and chromosomal alterations in PZ5. Downstream water samples from Portão Stream exhibited similarly heightened MN levels. This study's investigation into water quality is a concrete example of the implications of improper USW management. These findings underscore the pressing need for effective waste management strategies to mitigate environmental degradation and protect public health. [ABSTRACT FROM AUTHOR]

The application of industrial solid waste coal gangue (CG) in gas explosion suppression is explored, which opens up a new way for the resource utilization of CG. Two modified CG anti‐explosion agents, first‐grade modified CG (RCG) and second‐grade modified CG (MCG), were prepared by roasting activation and acid–base synergistic excitation. The explosion suppression performance of CG, RCG, and MCG was investigated through a 2.5 L semi‐closed explosion pipe. The experimental results were compared and analyzed, and their pyrolysis characteristics, phase composition, and particle size were analyzed to reveal their explosion suppression mechanism. It was proved that MCG had the best explosion suppression effect. Under the condition of 9.5% methane–air, it was found that the explosion suppression effect was most significant when the powder mass of the three powders was 300, 360, and 360 mg, respectively. The peak explosion overpressure is reduced by 10.51%, 21.96%, and 32.66%, respectively, and the peak arrival time of flame velocity is extended by .14 times, .20 times, and 1.15 times, respectively. MCG can effectively inhibit methane explosion utilizing physical and chemical synergistic heat absorption, porous structure formation barrier, heat isolation, oxygen dilution, adsorption, and capture of free radicals. [ABSTRACT FROM AUTHOR]

Expansive soils pose significant challenges in civil engineering due to their susceptibility to volumetric changes, leading to structural instability and damage in infrastructure. This study evaluates the performance and microstructural characteristics of industrial solid waste materials (Class F‐fly ash and ground granulated blast‐furnace slag) as additives for stabilizing expansive soils. Tests, including moisture density, unconfined compressive strength, Atterberg limits, compressibility index (Cc), cation exchange capacity, direct shear test, and California bearing ratio, were conducted on the treated expansive soil. Scanning electron microscopy and energy dispersive X‐ray spectroscopy (EDX) were used to analyze the changes in the soil matrix due to the incorporation of the waste materials. The results demonstrate improved engineering properties of expansive soil treated with these additives. The analysis confirms enhancements in particle arrangement, reduced porosity/pore sizes, and improved bonding between soil particles, indicating the formation of calcium silicate hydrate and calcium aluminate hydrate. This research suggests that these waste materials can be eco‐friendly and cost‐effective alternatives for stabilizing expansive soils in construction projects. [ABSTRACT FROM AUTHOR]

Industrial solid waste (mine tailings) management has emerged as the key universal ecological challenge as a result of the unceasing creation of rising waste by-products. Employing tailings makes mine fill production economical and assists resolve disposal problems. Foamed cement-based tailings backfill (FCTB) is a mine fill consisting of tailing, cement, water, and foaming agents. It provides certain advantages such as lightweight, good fluidity, and thermal insulation yet is relatively weak in strength. Additionally, FCTB's strength properties can be intensely improved by adding fibers. A total of three diverse fibers: polypropylene (PP), glass (G), and basalt (B) as well as dodecyltrimethylammonium bromide (DTAB) as a foaming agent were used to prepare fiber-reinforced foamed cementitious tailings backfill (FR-FCTB). The mechanical properties, energy evolution, ductility, and microstructure of FR-FCTB were elaborately investigated by uniaxial compression tests (UCS) and SEM. Laboratory findings demonstrate the reinforcing effect of three fibers on FCTB specimens: glass > polypropylene > basalt. FR-FCTB showed the best strength features as a fiber content of 0.3% was adopted in FCTB. At this time, the UCS performance of glass fiber-reinforced FCTBs was 0.85 MPa increased by 18.1%. The addition of fibers can increase the fill's energy storage limit, slow down the discharge of elastic strain energy within the backfill, and enhance the fill's ductility and toughness. The ductility factor evaluates the degree of deterioration of filling in terms of post-peak drop, with all FR-FCTB values being greater than CTB. FR-FCTB's chief hydration product is the C-S–H gel. Fiber's bridging effect significantly rallies crack extension and thus fill's strength features. Lastly, the study's main results are instructive for the industrial application of FR-FCTB used in metallic mines. [ABSTRACT FROM AUTHOR]

Due to industrialization, soil heavy metal pollution is a growing concern, with humic substances (HS) playing a pivotal role in soil passivation. To address the long duration of the compost humification problem, coal fly ash (CFA) in situ catalyzes the rapid pyrolysis of the cotton stalk (CS) to produce HS to address Cd passivation. Results indicate that the highest yield of humic acid (HA) (8.42%) and fulvic acid (FA) (1.36%) is obtained when the CS to CFA mass ratio is 1:0.5, at 275 ℃ for 120 min. Further study reveals that CFA catalysis CS humification, through the creation of alkaline pyrolysis conditions, Fe2O3 can stimulate the protein and the decomposition of hemicellulose in CS, and then, through the Maillard and Sugar-amine condensation reaction synthesis HA and FA. Applying HS-CS&CFA in Cd-contaminated soil demonstrates a 26.69% reduction in exchangeable Cd within 30 days by chemical complexation. Excellent maize growth effects and environmental benefits of HS products are the prerequisites for subsequent engineering applications. Similar industrial solid wastes, such as steel slag and red mud, rich in Fe2O3, can be explored to identify their catalytic humification effect. It could provide a novel and effective way for industrial solid wastes to be recycled for biomass humification and widely applied in remediating Cd-contaminated agricultural soil. [ABSTRACT FROM AUTHOR]

The utilization of industrial solid waste in mines is an important approach to resource utilization. The backfill material in mines is mainly composed of solid waste, which plays a supporting role. The excitation effect of lime on phosphogypsum and fly ash in backfill was studied in this paper. The macroscopic and microscopic characteristics of the backfill material were tested using uniaxial compression, nuclear magnetic resonance, scanning electron microscopy, and electrochemical techniques, and a relationship model was established between them. Furthermore, the influence of industrial solid waste on the properties of the backfill material under the action of lime and the hydration mechanism between different industrial solid wastes were studied. The results show that (1) under the action of lime, fly ash reacts with lime to produce C-S-H and C-A-H, and then C-A-H reacts with phosphogypsum to produce AFt. (2) The excess phosphogypsum also fills the pores. Therefore, 1.8% lime reduces the porosity of the backfill by 17.88% and increases the strength by 21.57%. (3) The cross-scale relationship shows that strength is inversely proportional to each type of pore content and fractal dimension, and it logarithmically increases with impedance at different frequencies. The lower the frequency, the stronger the relationship is. (4) This study indicates that industrial solid waste is a suitable cement replacement. [ABSTRACT FROM AUTHOR]

Prior research has demonstrated that incorporating solid waste from various sources, such as plastics, civil engineering waste, and industrial and mining waste, into pavement and civil works mixes has notable environmental benefits. This includes reducing the over-exploitation of aggregate banks and preventing waste materials from being deposited in open-pit landfills for extended periods. This review focuses on sustainable aggregates produced from solid waste with rheological or mechanical properties suitable for replacing conventional aggregates in asphalt or hydraulic concrete mixtures. The aim is to determine the optimal replacement percentage in the mixture to directly impact pavement performance. This review also delves into the impact on fatigue resistance and permanent deformation based on the type of waste material used in construction. Additionally, using sustainable aggregates presents added benefits for pavement binders, such as inhibiting reflection cracks, reducing traffic noise, and prolonging the service life of the pavement. However, it is crucial to study the percentage of replacement of sustainable aggregates in conjunction with other materials using mathematical models and simulations to ensure a substantial contribution to the sustainability of the construction industry. [ABSTRACT FROM AUTHOR]

Recycling industrial solid wastes as building materials in the construction field exhibits great environmental benefits. This study designed an eco-friendly non-sintered brick by combining multiple industrial solid wastes, including sewage sludge, fly ash, and phosphorus gypsum. The mechanical properties, microstructure, and environmental impacts of waste-based non-sintered bricks (WNBs) were investigated comprehensively. The results revealed that WNB exhibited excellent mechanical properties. In addition, steam curing could further promote the strength development of WNB. The compressive strength of WNB with 10 wt% of sewage sludge reached 13.5 MPa. Phase assemblage results indicated that the incorporation of sewage sludge promoted the generation of ettringite. Mercury intrusion porosimetry results demonstrated that the pore structure of WNB varies with the dosage of sewage sludge. Life-cycle assessment results revealed that the energy consumption and CO2 emission of WNB were 45% and 17% lower than those of traditional clay bricks. Overall, the development of WNB in this study provided insights into the co-disposal of industrial solid wastes. [ABSTRACT FROM AUTHOR]

Present study assessed the growth of two plant species and ion uptake by them grown on different proportion of industrial solid waste and garden soil. The industrial waste having high concentration of chemicals were used with garden soil at different proportion i.e. 0% (T0), 5% (T1), 10% (T2), 15% (T3) and 20% (T4). Two species namely Conocarpus erectus (alien plant) and Dodonaea viscosa (indigenous) were used as test plants in pot study. Different parameters including growth, physiology, and anatomy of plants and concentration of cations (Na+, K+, Ca2+, and Mg2+) in the plant shoot and root were measured at different time duration (initial, 1st, 2nd, 3rd and 4th month). The key objective of the study was to use these plants to establish their plantations on the barren lands where industrial solid wastes were being disposed of. C. erectus showed better growth than D. viscosa, as well as more uptake of ions. A significant increase in plant growth was observed in fourth month in T1, where plant height reached 24.5% and 46% for C. erectus and D. viscosa, respectively. At harvest, in C. erectus, no significant difference in the fresh (65–78 g) and dry weight (24–30 g) of the shoot was observed across treatments compared to the control. In D. viscosa, at the time of harvest, the fresh and dry weights of the root and shoot showed a strong, significantly decreasing pattern across T1, T2, and T3, leading to the death of the plant at T3 and T4. Further, optimum ratio of waste soil to garden soil was found as 10:90 and 20:80 to establish the plantations of D. viscosa and C. erectus, respectively in areas where such solid waste from industries are disposed. Findings can be used for the restoration of such solid waste for the sustainable management of industrial areas and their associated ecosystems. [ABSTRACT FROM AUTHOR]

Red mud (RM), a hazardous solid waste generated in the alumina production process, of which the mineral composition is mainly hematite, is unable to be applied directly in the cement industry due to its high alkalinity. With the rise of geopolymers, RM-based grouting materials play an essential role in disaster prevention and underground engineering. To adequately reduce the land-based stockpiling of solid wastes, ultrafine calcium oxide, red mud, and slag were utilized as the main raw materials to prepare geopolymers, the C-R-S (calcium oxide–red mud–slag) grouting cementitious materials. The direct impact of red mud addition on the setting time, fluidity, water secretion, mechanical properties, and rheological properties of C-R-S were also investigated. In addition, a scanning electron microscope (SEM), X-ray diffraction (XRD), three-dimensional CT (3D-CT), Fourier transform infrared spectroscopy (FT-IR), and other characterization techniques were used to analyze the microstructure and polymerization mechanism. The related results reveal that the increase in red mud addition leads to an enhanced setting time, and the C-R-S-40 grouting cementitious material (40% red mud addition) exhibits the best fluidity of 27.5 cm, the lowest water secretion rate of 5.7%, and a high mechanical strength of 57.7 MPa. The C-R-S polymer grout conforms to the Herschel–Bulkley model, and the fitted value of R2 is above 0.99. All analyses confirm that the preparation process of C-R-S grouting cementitious material not only substantially improves the utilization rate of red mud, but also provides a theoretical basis for the high-volume application of red mud in the field of grouting. [ABSTRACT FROM AUTHOR]

In the context of the circular economy, there is a need for advanced methods to recover metals from industrial waste, yet classical hydrometallurgical techniques are limited. Here, we review ultrasonic-assisted hydrometallurgical leaching with focus on the use of acids, bases, oxidants, bacteria and electrolysis. Oxidative leaching is done with ferric ions, dioxygen, ozone and hydrogen peroxide. Upscaling is also detailed. Ultrasonication allows to reduce the dosage of leaching agents, to reduce reaction time, and to enhance leaching efficiency. Large-scale equipments are still limited by low cavitation efficiency, low throughput, high usage costs, and high energy consumption. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present study illustrates the rapid pollution of Euphrates River, inwards Al-Najaf Al-Ashraf governance (Al-Kufa River) in Iraq, which is one of the most important rivers in the region. The river faces formidable pressure due to encroachments, discharge of untreated domestic and industrial waste, drainage water from cultivated orchards, and dumping of solid waste. This study was conducted to assess the temporary and locative organic pollution in the region. Water Quality Index (WQI) of the Al-Kufa river was determined according to the Canadian Council of Ministers of Environment (CCME) method by calculating seven parameters (water temperature, DO, COD, EC, TDS, turbidity, and pH) in two sampling stations. Surface water samples were collected in a period of four months (September to December) in 2023. WQI level, correlation analysis between parameters, and Iraqi and CCME drinking water specification standards were employed to classify the surface water status. The results show that the ecological condition can be classified as marginal with WQI= 49 and poor with WQI= 42 in stations 1 and 2, respectively. [ABSTRACT FROM AUTHOR]

The soil, comprising minerals, organic matter, and living organisms, serves as a critical component of our environment. However, anthropogenic activities, such as uncontrolled sewage disposal and industrial waste, have led to pervasive soil pollution, impacting ecosystems and human health. This comprehensive study scrutinizes the intricate dynamics of soil pollution resulting from open waste dumping, specifically examining its impact on the health of local communities and the environment in Haridwar municipality. In this study, four solid waste dumping sites were meticulously surveyed, with soil samples analyzed for 19 parameters through statistical tools like one-way ANOVA, Kruskal–Wallis tests, soil pollution indices, and potential health risk assessment. The Geo-accumulation Index (Igeo) and contamination factor (CF) followed the heavy metals in the order of Zn > Mn > Fe > Cu in all selected sites. Additionally, a potential health risk assessment considered ingestion, inhalation, and dermal exposure pathways, revealing a high non-carcinogenic risk of metals (Mn > Fe > Zn > Cu) for both children and adults. In the ingestion pathway, the hazard quotient indicated a high risk of metals for both children and adults in the range of 1192.73 to 2066.94 for child and 191.98 to 312.16 for adults. Crucially, the HQ revealed potential health risks, emphasizing the urgency of addressing metal contamination. However, the findings indicate that dumping sites directly or indirectly affects the local people of Haridwar municipality. Therefore, this study provides a baseline framework for minimizing the impact of dumping sites on local population and the environment. [ABSTRACT FROM AUTHOR]

[Display omitted] • The refractory oxides of the W-residue formed a harmless slag after smelting with SKW. • Photovoltaic sawing waste was applied as a high-efficient silicothermic reductant. • Heavy metal oxides in W-residue were converted into high-value alloy phase. • An overall recovery rate of valuable metals of 91.7% was achieved. • The synergistic recovery mechanism of two industrial wastes was studied. Solid waste challenges in both the tungsten and photovoltaic industries present significant barriers to achieving carbon neutrality. This study introduces an innovative strategy for the efficient extraction of valuable metals from hazardous tungsten leaching residue (W-residue) by leveraging photovoltaic silicon kerf waste (SKW) as a silicothermic reducing agent. W-residue contains 26.2% valuable metal oxides (WO 3 , CoO, Nb 2 O 5 , and Ta 2 O 5) and other refractory oxides (SiO 2 , TiO 2 , etc.), while micron-sized SKW contains 91.9% Si with a surface oxide layer. The impact of SKW addition on the silicothermic reduction process for valuable metal oxides in W-residue was investigated. Incorporating SKW and Na 2 CO 3 flux enables valuable metal oxides from W-residue to be effectively reduced and enriched as a valuable alloy phase, with unreduced refractory oxides forming a harmless slag phase during the Na 2 O-SiO 2 -TiO 2 slag refining process. This process achieved an overall recovery yield of valuable metals of 91.7%, with individual recovery yields of W, Co, and Nb exceeding 90% with the addition of 8 wt.% SKW. This innovative approach not only achieves high-value recovery from W-residue and utilization of SKW but also minimizes environmental impact through an efficient and eco-friendly recycling pathway. The strategy contributes significantly to the establishment of a resource-efficient circular economy, wherein the recovered high-value alloy phase return to the tungsten supply chain, and the harmless slag phase become raw materials for microcrystalline glass production. [ABSTRACT FROM AUTHOR]

Phosphogypsum (PG) occupies a large amount of land due to its large annual production and low utilization rate, and at the same time causes serious environmental problems due to toxic impurities. PG is used for mine backfill, and industrial solid waste is a curing agent for PG, which can save the filling cost and reduce environmental pollution. In this paper, PG was used as a raw material, combined with steel slag (SS) and ground granulated blast-furnace slag (GGBS) under the action of an alkali-activated agent (NaOH) to prepare all-solid waste phosphogypsum-based backfill material (PBM). The effect of the GGBS to SS ratio on the compressive strength and toxic leaching of PBM was investigated. The chemical composition of the raw materials was obtained by XRF analysis, and the mineral composition and morphology of PBM and its stabilization/curing mechanism against heavy metals were analyzed using XRD and SEM-EDS. The results showed that the best performance of PBM was achieved when the contents of PG, GGBS, and SS were 80%, 13%, and 7%, the liquid-to-solid ratio was 0.4, and the mass concentration of NaOH was 4%, with a strength of 2.8 MPa at 28 days. The leaching concentration of fluorine at 7 days met the standard of groundwater class IV (2 mg/L), and the leaching concentration of phosphorus was detected to be less than 0.001 mg/L, and the leaching concentration of heavy metals met the environmental standard at 14 d. The hydration concentration in PBM met the environmental standard. The hydration products in PBM are mainly ettringite and C-(A)-S-H gel, which can effectively stabilize the heavy metals in PG through chemical precipitation, physical adsorption, and encapsulation. [ABSTRACT FROM AUTHOR]

The escalating emissions of CO2 exacerbate global warming. Carbon capture offers a potential avenue to attenuate CO2 emissions, but the high cost of adsorbents acts as a barrier to the development of carbon capture technologies. Simultaneously, the continual increase in coal combustion leads to a rise in fly ash production, yet its valorization remains relatively low. Utilizing fly ash for synthesizing fly ash-based aluminosilicate materials and their application in carbon capture technologies present a dual solution by valorizing industrial solid waste and reducing carbon emissions. The preprocessing steps prior to synthesizing fly ash-based aluminosilicate materials were outlined and the research on synthesis of fly ash-based zeolites, Li4SiO4 adsorbents, and SiO2 mesoporous materials and their synthesis were systematically discussed, and the kinetics of CO2 adsorption on fly ash-based aluminosilicate materials were summarized. Physical and chemical preprocessing steps before preparing fly ash-based aluminosilicate materials optimize the materials' pore structure and surface chemical properties. Strategies such as amine functionalization or metal ion doping enable control over the material structure and CO2 capture performance. Discrepancies in the kinetics of CO2 capture on fly ash-based aluminosilicate materials arise from variations in reaction products and capture conditions. In-depth theoretical research and promoting large-scale engineering applications hold significant promise in guiding the development of carbon capture technologies. [ABSTRACT FROM AUTHOR]

The increased usage of diesel in the past 20 years, particularly in developing countries like India, has resulted in serious concerns in abating gaseous pollutants such as oxides of nitrogen (NOX) and hydrocarbons (HC). On the other hand, the growing metallurgical processing industries leave behind tons of solid waste, making waste management a bigger issue. In the current work several industry wastes have been tested under discharge plasma environment for their catalytic properties in the removal of HCs from diesel exhaust. To explore the benefit of metal oxide components, present in industry wastes, a new approach was proposed in this work wherein two industrial wastes were blended to form a composite waste which was then powdered and bound to form pellets. Four such composite waste-based pellets, namely red mud + iron tailing, iron tailing + lignite ash, lignite ash + copper slag and red mud + oyster shells, were tested for their catalytic properties under plasma environment. Exhaust emanating from a 6 HP engine is sampled and studied for HC removal in a pulsed plasma reactor embedded with composite wastes. The pellets being porous in nature, studies were also conducted for HC adsorption by cascading composite wastes with plasma alone while treating the exhaust. All the composite wastes exhibited good plasma catalysis in HC removal (58–73%) when compared to that with plasma alone (31%). Further, there is a marked difference between plasma adsorption and plasma catalysis by a factor of 1.75–2.2 indicating synergy between plasma and metal oxides present in composite wastes while catalysing HC removal. [ABSTRACT FROM AUTHOR]

80% of the raw materials for industrial products in our country come from mineral resources, resulting in a large amount of industrial solid waste. Among them, red mud is a typical industrial hazardous waste. If its not properly disposed, it will cause harm to atmosphere, water, soil etc. At the same rime, red mud also has resource attributes. If reasonably utilized, It will replace some raw material, which meets the requirements of Chinese 14th Five Year Plan for the development of circular economy. This paper summarizes the current situation of red mud production, storage, and pollution in China, as well as the advantages and disadvantages of current comprehensive utilization methods. The production of red muds large, with a storage capacity of over hundreds of millions of tons. The pollution problem has become more prominent and its currently mainly applied in the fields of metallurgy, building materials, and environmental protection. The direction of large-scale resource utilization of red muds proposed, boost China to achieve the "carbon peaking and carbon neutrality goal". [ABSTRACT FROM AUTHOR]

Increasing world population, urbanization, and industrialization have led to an increase in demand in production and consumption, resulting in an increase in industrial solid wastes and pollutant levels in water. These two main consequences have become global problems. The high Si and Al content of solid wastes suggests that they can be used as raw materials for the synthesis of zeolites. In this context, when the literature studies conducted to obtain synthetic zeolites are evaluated, it is seen that hydrothermal synthesis method is generally used. In order to improve the performance of the hydrothermal synthesis method in terms of energy cost, synthesis time, and even product quality, additional methods such as alkaline fusion, ultrasonic effect, and microwave support have been developed. The zeolites synthesized by different techniques exhibit superior properties such as high surface area and well-defined pore sizes, thermal stability, high cation exchange capacity, high regeneration ability, and catalytic activity. Due to these specific properties, zeolites are recognized as one of the most effective methods for the removal of pollutants. The toxic properties of heavy metals and dyes in water and their carcinogenic effects in long-term exposure pose a serious risk to living organisms. Therefore, they should be treated at specified levels before discharge to the environment. In this review study, processes including different methods developed for the production of zeolites from industrial solid wastes were evaluated. Studies using synthetic zeolites for the removal of high levels of health and environmental risks such as heavy metals and dyes are reviewed. In addition, EPMA, SEM, EDX, FTIR, BET, AFM, and 29Si and 27Al NMR techniques, which are characterization methods of synthetic zeolites, are presented and the cation exchange capacity, thermodynamics of adsorption, effect of temperature, and pH are investigated. It is expected that energy consumption can be reduced by large-scale applications of alternative techniques developed for zeolite synthesis and their introduction into the industry. It is envisaged that zeolites synthesized by utilizing wastes will be effective in obtaining a green technology. The use of synthesized zeolites in a wide variety of applications, especially in environmental problems, holds great promise. [ABSTRACT FROM AUTHOR]

Disposal and harmless utilization of coal-based solid waste, industrial sludge, and other bulk industrial solid waste is a sustainable and economical approach. In this study, coal gangue and printing and dyeing sludge were recycled to reconstruct high-strength ceramsite using a simple and scalable method. The high silica and alumina contents in coal gangue provided a foundation for ceramsite preparation, and the iron oxide in the printing and dyeing sludge could reduce the sintering temperature. The optimal synthesis conditions were as follows: Coal gangue: printing and dyeing sludge = 40:60; sawdust content of 9mass%; sintering temperature of 1175 °C for 15 min; and preheating temperature of 400 °C for 10 min. The designed ceramsite exhibited high compressive strength of 27.26 MPa, low 1-h water absorption of 1.26%, and bulk and apparent densities of 998 and 1597 kg/m3, respectively; thus, it was categorized as high-strength ceramsite. In determining the modelling mechanism during the sintering process, the silicon and aluminum distributions on the ceramsite surface obtained under the optimal preparation conditions was highly consistent, forming a silicoaluminate that supported the ceramsite strength. Sawdust addition increased the pore structure of the ceramsite. The heavy metals contained in the raw materials were well-immobilized in the ceramsite, indicating that the prepared ceramsites were free from secondary contaminants. Use of bulk solid waste to prepare high-strength ceramsites is a feasible resourceful and harmless utilization method, which is of great significance for bulk solid waste disposal and reuse. [Display omitted] • Coal gangue and printing and dyeing sludge were synergistic disposed. • High-strength ceramsite with high performance was prepared. • Preparation conditions for the optimum performance of ceramsites were obtained. • High-strength ceramsite has minimal secondary pollution to the environment. [ABSTRACT FROM AUTHOR]

We report the effects of sodium phosphate dodecahydrate (Na3PO4·12H2O) as a foam stabilizer on the crystalline phases, microstructure, and properties of foamed glass–ceramics derived from solid industrial wastes. Our findings reveal that Na3PO4·12H2O acts as a pore structure stabilizer, enhancing pore uniformity by releasing P2O5 during decomposition. Additionally, it lowers the softening temperature and viscosity by supplying Na2O. X‐ray diffraction analysis demonstrates that Na3PO4·12H2O does not alter the primary crystal types but does influence the crystallinity and morphology. With an increase in Na3PO4·12H2O content, the porosity and water absorption improve, but the bulk density, thermal conductivity, and compressive strength decrease. The optimal properties are achieved with 4 wt% Na3PO4·12H2O, resulting in significantly higher compressive strength compared to foamed glass–ceramics prepared from other solid wastes. This study provides valuable guidelines for effectively reusing solid industrial wastes to fabricate foamed glass–ceramics. [ABSTRACT FROM AUTHOR]

Solid wastes have become one of the most critical problems in urban areas because of the increase in the amount and the environmental problems caused by the variety of these wastes. In the same local governments where waste management is mismanaged, much money is wasted, and landfills are unnecessarily occupied. Making a profit out of solid wastes, seen as a heavy burden to the world and our country, aims firstly to collect these wastes apart from their sources by characterizing them. Recycling of both household and industrial wastes should be planned and done at the source. Collection is the most laborious and costly element of solid waste management. The study area was divided into four groups according to income levels, and the waste generated there was evaluated. The study showed that for 2022, kitchen waste ranks first with 67.25%. Kitchen waste is followed by packaging waste at 21.03%; flammable wastes (textile etc.) at 21.04%; ash waste at 44%, While hazardous wastes have a share of 0.55%; lastly, park and garden wastes and electronic wastes were not detected at all. It is seen that waste management activities are carried out in the Çayırova region, but the integration of citizens into waste management activities needs to be increased. In this regard, improvement efforts have been made to increase efficiency in separating collection from the source and reduce the amount of final waste. [ABSTRACT FROM AUTHOR]

The awareness of the concept of the "Circular Economy" is motivating scientists to convert drinking water treatment plant by-products, which are based on aluminum waste, into a valorized material for wastewater treatment. Alum sludge from a local waterworks plant in Egypt was collected and dewatered using chitosan-coated magnetic nanoparticles. The role of the conditioned sludge in wastewater treatment was then examined. Chitosan (Ch) augmented with magnetite nanoparticles (MNs), labeled as ChMNs, was prepared by means of a simple co-precipitation route with mixing ratios of 1:1, 2:1, and 3:1 of chitosan and magnetite nanoparticles to form the ChMN catalyst. The ChMNs were shown to beneficially enhance alum sludge conditioning and dewaterability. The conditioned and dried aluminum-based sludge (AS) loaded with ChMNs was then used as a source of Fenton's catalyst for Synozol Red-KHL textile dyeing wastewater. The characteristics of the AS-ChMN sample were investigated using Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The photocatalytic activity of the AS-ChMN composite was assessed by examining its diffuse reflectance spectra (DRS). Response surface methodological analysis was applied to optimize the operational parameters in order to reduce the use of chemicals and improve dye oxidation to form a complete (99%) dye oxidation strategy. The experiments demonstrated that the optimal operating parameters included doses of 1.5 g/L and 420 mg/L for AS-ChMNs and hydrogen peroxide, respectively, as a source of Fenton's reaction at a working pH of 3.5. Kinetic and thermodynamic analyses for potential full-scale applications were conducted, showing the reaction to be exothermic and spontaneous in nature and following second-order reaction kinetics. Hence, the novelty of this work lies in the introduction of conditioned and dewatered alum sludge waste as a photocatalyst for textile dye effluent oxidation, which could be considered a "win–win" strategy. [ABSTRACT FROM AUTHOR]

The high-temperature composite phase change materials (HCPCMs) were prepared from solid waste blast furnace slag (BFS) and NaCl-KCl binary eutectic salt to achieve efficient and cost-effective utilization. To ensure good chemical compatibility with chlorine salt, modifier fly ash (FA) was incorporated and subjected to high-temperature treatment for the processing of industrial solid waste BFS, which possesses a complex chemical composition. The HCPCMs were synthesized through a three-step process involving static melting, solid waste modification, and mixing–cold pressing–sintering. Then, the influence of the modification method and the amount of SiC thermal conductivity reinforced material on chemical compatibility and thermodynamic performance was explored. The results demonstrate that the predominant phase of the modified solid waste is Ca2Al2SiO7, which exhibits excellent chemical compatibility with chlorine salt. HCPCMs containing less than 50 wt.% chloride content exhibit good morphological stability without any cracks, with a melting temperature of 661.76 °C and an enthalpy value of 108.73 J/g. Even after undergoing 60 thermal cycles, they maintain good chemical compatibility, with leakage rates for melting and solidification enthalpies being only 6.3% and 0.23%, respectively. The equilibrium was achieved when 40 wt.% of chloride salt was encapsulated upon the addition of 10% of SiC, and the incorporation of SiC resulted in an enhancement of thermal conductivity for HCPCMs to 2.959 W/(m·K) at room temperature and 2.400 W/(m·K) at 200 °C, with an average increase of about 2 times. The cost of the prepared HCPCMs experienced a significant reduction of 81.3%, demonstrating favorable economic performance and promising prospects for application. The research findings presented in this article can offer significant insights into the efficient utilization of solid waste. [ABSTRACT FROM AUTHOR]

CO2 mineralization plays a critical role in the storage and utilization of CO2. Coal fly ash (CFA) and red mud (RM) are widely utilized as CO2 mineralizers. However, the inert calcium species in CFA limit its carbonation capacity, meanwhile the substantial Ca2+ releasing of RM is hindered by a covering layer of calcium carbonate. In this study, CO2 mineralization in a composite system of CFA and RM was investigated to enhance the carbonation capacity. Multiple analyzers were employed to characterize the raw materials and resulting mineralization products. The results demonstrated that a synergistic effect existed in the composite system of CFA and RM, resulting in improving CO2 mineralization rate and efficiency. The produced calcium carbonate was ectopically attached the surface of CFA in the composite system, thus slowing down its coverage on the surface of RM. This phenomenon facilitated further releasing Ca2+ from the internal RM, thereby enhancing CO2 mineralization efficiency. Meanwhile, the inclusion of RM significantly improved the alkalinity of the composite system, which not only promoted the dissolution of Ca2+ of the inert CaSO4(H2O)2 in CFA, but also accelerated CO2 mineralization rate. The investigation would be beneficial to CO2 mineralization using industrial solid wastes. [ABSTRACT FROM AUTHOR]

Alkali-activated materials are gaining much interest due to their outstanding performance, including their great resistance to chemical corrosion, good thermal characteristics, and ability to valorise industrial waste materials. Reusing waste glasses in creating alkali-activated materials appears to be a viable option for more effective solid waste utilisation and lower-cost products. However, very little research has been conducted on the suitability of waste glass as a prime precursor for alkali activation. This study examines the reuse of seven different types of waste glasses in the creation of geopolymeric and cementitious concretes as sustainable building materials, focusing in particular on how using waste glasses as the raw material in alkali-activated materials affects the durability, microstructures, hydration products, and fresh and hardened properties in comparison with using traditional raw materials. The impacts of several vital parameters, including the employment of a chemical activator, gel formation, post-fabrication curing procedures, and the distribution of source materials, are carefully considered. This review will offer insight into an in-depth understanding of the manufacturing and performance in promising applications of alkali-activated waste glass in light of future uses. The current study aims to provide a contemporary review of the chemical and structural properties of glasses and the state of research on the utilisation of waste glasses in the creation of alkali-activated materials. [ABSTRACT FROM AUTHOR]

Iron ore tailings (IOT) are industrial solid wastes that pose environmental threats. This study prepared IOT-biochar composite materials as multifunctional soil conditioners through an in-situ growth method. Biochar served as a carrier to improve the dispersity and reactivity of IOT in soil. The IOT-biochar composite (FeOT-BC) showed balanced impacts on soil properties, increasing pH, organic matter and available nutrients compared to IOT alone. This was due to the buffering effects of biochar. In pot experiments, FeOT-BC significantly promoted rice plant growth compared to IOT alone. The improvements were attributed to the improved soil fertility and increased microbial activities induced by biochar. The results suggest that integrating IOT with biochar can mitigate the negative effects of tailings and convert them into a value-added product. The biochar component can optimize the performance of IOT by moderating soil acidification, enhancing nutrient release from iron minerals, and stimulating microbial activities. The IOT-biochar composite materials integrate the functionalities of both components for optimized soil conditioning effects, providing a promising strategy for comprehensive tailings utilization. [ABSTRACT FROM AUTHOR]

Although calcined clay-blended cement offers higher performance and durability compared to neat Portland cement (PC), its extensive use of natural clay leads to the depletion of natural non-renewable resources. To address this concern, this study focuses on the utilization of supplementary cementitious materials-based waste products as a substitute for PC. The blended cement was optimized with a low replacement level of 10 wt.% calcined Fanja clay (FNJ) as a low-grade metakaolin (MK) and 90 wt.% PC. Various types of industrial solid wastes (ISWs) were incorporated into the PC-FNJ blend in place of PC. The ISWs utilized included silicate-rich wastes, such as silica fume (SF) and glass waste (GW) powder, as well as silicate-less waste, such as marble dust (MD). The results revealed that incorporating 10 wt.% SF into the PC-FNJ mixture resulted in a considerable decrease in the flow rate while improving its early mechanical strength. GW, as another silicate waste, also enhanced early mechanical properties but not as much as SF. However, the composite of PC-FNJ-GW exhibited higher workability than the neat PC, PC-FNJ, and PC-FNJ-SF. The mixtures of PC-FNJ-MD demonstrated the same trend. Embedding SF into PC-FNJ-GW and PC-FNJ-MD substantially decreased both their flowability and mechanical properties. Nonetheless, all composites containing ISWs showed higher flexural strength, higher resistivity to chloride diffusivity, and higher or comparable acid and salt resistivity. [ABSTRACT FROM AUTHOR]

The present study directs the need for the development of an economical composite mix comprised locally available soil and industrial waste which satisfy the design parameters of the municipal solid waste (MSW) landfill. The local soil, bentonite, and fly ash mixtures are mixed in different proportions to evaluate the geotechnical and microstructural characteristics for suggesting an optimum composite mix that fulfills the design parameters of landfill liners. The curing periods of different mixes are also considered while evaluating the unconfined compressive strength (UCS) characteristics. The microstructure of the mixtures is examined using advanced imaging techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDAX) to gain insights into the changes at the microscale level due to the inclusion of fly ash. It is observed that soil-bentonite-fly ash composite mix in a ratio of 65:15:20 aligns with the optimal design characteristics required for a landfill liner. Notably, for this composite mix, both liquid limit (LL) and plastic limit (PL) show a significant increase of 48.57% and 32.33% respectively, while the optimum moisture content (OMC) rises by 11.25%. Conversely, maximum dry density (MDD) experiences an 8.79% decrease. Moreover, the free swell index (FSI) escalates by 113%, whereas hydraulic conductivity (HC) records a substantial reduction of 96.04%. Moreover, the UCS exhibited a notable increase of 209% after a 28-day curing period. The highest strength is achieved initially by soil mixed with 20% fly ash, followed by a blend containing 15% bentonite. Therefore, proper fly ash content in filler and other binder materials is an effective and sustainable approach that not only solves the disposal issue but also enhances the material's engineering characteristics, justifying its suitability to be used as a landfill liner. [ABSTRACT FROM AUTHOR]

The transformation of solid wastes from industrial production into effective adsorbents could significantly contribute to wastewater treatment. In this study, after acidizing and burning soft scale (SS) from coal gasification system, two magnetic adsorbents (mag-ASS and mag-BASS) were prepared via the combination of magnetite with ultrasonic, respectively. The treatment effects of mag-ASS and mag-BASS were then investigated for simulated wastewater containing macromolecular organic matter [i.e., methylene blue (MB)] and Ca2+. The results indicated that the pseudo second order kinetic, Elovich, Freundlich, Langmuir and Temkin model could well describe the adsorption behavior of MB and Ca2+ onto mag-ASS and mag-BASS. The maximum adsorption capacities of mag-ASS for MB and mag-BASS for Ca2+ were 600.53 mg/g and 102.54 mg/g, respectively. Surprisingly, the adsorption abilities of mag-ASS for MB and mag-BASS for Ca2+ show significantly higher than the others. The adsorption mechanisms of MB mainly included electrostatic interaction, π-π conjugate interaction and cation exchange, while those of Ca2+ were mainly electrostatic interaction and cation exchange. The diffusion of MB and Ca2+ onto the magnetic adsorbents might be controlled by the combined effects of intraparticle and liquid film diffusion. There was no significant reduction in adsorption capacity after 8 cycles of adsorption and desorption, indicating that SS-based magnetic adsorbents had good recyclability and stability. Moreover, the removal efficiency of mag-BASS for total hardness and total organic carbon in real coal gasification gray water (CGGW) was 82.60 and 64.10%, respectively. The treatment of CGGW and the resource of wastes would significantly promote the reasonable disposal of coal gasification scales. [ABSTRACT FROM AUTHOR]

As one of the key materials used in the civil engineering industry, concrete has a global annual consumption of approximately 10 billion tons. Cement and fine aggregate are the main raw materials of concrete, and their production causes certain harm to the environment. As one of the countries with the largest production of industrial solid waste, China needs to handle solid waste properly. Researchers have proposed to use them as raw materials for concrete. In this paper, the effects of different lithium slag (LS) contents (0%, 10%, 20%, 40%) and different substitution rates of recycled fine aggregates (RFA) (0%, 10%, 20%, 30%) on the axial compressive strength and stress-strain curve of concrete are discussed. The results show that the axial compressive strength, elastic modulus, and peak strain of concrete can increase first and then decrease when LS is added, and the optimal is reached when the LS content is 20%. With the increase of the substitution rate of RFA, the axial compressive strength and elastic modulus of concrete decrease, but the peak strain increases. The appropriate amount of LS can make up for the mechanical defects caused by the addition of RFA to concrete. Based on the test data, the stress-strain curve relationship of lithium slag recycled fine aggregate concrete is proposed, which has a high degree of agreement compared with the test results, which can provide a reference for practical engineering applications. In this study, LS and RFA are innovatively applied to concrete, which provides a new way for the harmless utilization of solid waste and is of great significance for the control of environmental pollution and resource reuse. [ABSTRACT FROM AUTHOR]

• Explore the relationship between industrial solid waste and socioeconomic. • Analyze the flow relationships among different sectors of industrial solid waste. • Determine the industrial solid waste discharge responsibility for each sector. • Identify the key sectors for industrial solid waste discharge. • Simulate industrial solid waste reduction measures. Rapid economic development inevitably leads to the discharge of a large amount of common industrial solid waste (CISW), which not only pollutes the environment but also restricts economic development in turn. In this study, a dynamic common industrial solid waste (DCISW) model is developed to analyze the retrospectively CISW development in Shanghai from 2000 to 2017 and simulate prospectively multi-perspective emission reduction measures. Specifically, the dynamic linkages between CISW and socio-economics are established at both the systematic and sectoral levels through input–output analysis, ecological network analysis, and related socio-economic indicators. Abatement measure simulations are conducted using RAS and other methods. The findings reveal that the growth of CISW in Shanghai is closely related to its fast-growing economy. The Others sector (OS) receives the most CISW from other sectors, while the Mining industry (MI) sends the most CISW to others. From production-based, consumption-based, and income-based perspectives, Chemical Products (CP) consistently remain the largest contributors. For the proposed waste generation intensity (WGI) indicator, the Mining industry (MI) is regarded as the main sector in all three perspectives. Moreover, the MI consistently emerges as the key sector of the system. CISW simulations indicate that improving the MI emission technology and increasing the MI output value will be top priorities for CISW emission reduction in Shanghai. This study is expected to provide scientific support to address the CISW problem in Shanghai and other similar fast-growing metropolises. [ABSTRACT FROM AUTHOR]

• Lack of studies on market concentration both on the supply and demand sides. • Case: commercial and industrial non-hazardous solid waste in Chile. • Tonnes valorised stagnated and valorisation rate dropped between 2015 and 2019. • Top 10 percent generation companies concentrate 90 percent of tonnes generated. • Top generators also concentrate between 20 and 40 percent of valorisation. Market concentration among buyers of recycled materials is a phenomenon discussed since the 1980 s by the anti-trust literature. Yet, there is still a lack of studies on simultaneous market concentration on both the supply and demand sides. This is particularly relevant when Extended Producer Responsibility (EPR) policies produce two-sided waste generation and valorisation markets. Thus, the purpose of this study is to explore the link between market concentration on the generation side and market share on the valorisation side. Specifically, this research addresses the case of valorisation of commercial and industrial non-hazardous waste in Chile. The analysis covers 261 companies that valorised industrial and commercial non-hazardous waste between 2015 and 2019. Being part of the top 10 % of generator companies in Chile is significantly correlated to higher valorisation market share, in a context in which mean market share per company decreased, total tons valorised stagnated, and the country-level valorisation rate diminished. [ABSTRACT FROM AUTHOR]

The huge demand for sand and gravel resources in road engineering construction leads to excessive consumption of resources and environmental damage. Recycling waste concrete and industrial solid waste as a road material is a promising alternative. In order to explore the application of these solid wastes in the road base, this paper studies the effect of adding lithium slag activated by an alkaline activator, fly ash (FA) and a combination of the two on the compressive strength, splitting strength and shrinkage performance of recycled cement-stabilized macadam mixture (RCSM). The optimum content of recycled aggregate (RA), alkali-activated lithium slag (AALS) and FA in composite-improved RCSM was optimized using a response surface method (Box–Behnken), and the microscopic characteristics of the mixture were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the optimum dosage of AALS, FA and RA determined by the response surface method is 15%, 10% and 40%, respectively. Compared with the cement-stabilized macadam mixture (CSM) with 40% RA, the 28 d compressive strength and 28 d splitting strength of the composite-improved RCSM are increased by 26.8% and 22.9%, respectively, and the dry shrinkage coefficient and average temperature shrinkage coefficient are decreased by 25.8% and 14.8%, respectively. Microscopic tests show that AALS and FA participate in the hydration reaction, generate more hydrated silicate (C-S-H) and ettringite (AFt), refine pores, effectively improve the performance of the internal interface transition zone of the mixture, make the microstructure of the mixture denser, and improve the strength and shrinkage performance of RCSM. This study provides technical support for the reuse of resources and the sustainable development of road construction. [ABSTRACT FROM AUTHOR]

Experimental investigations of the effectiveness of the pretreatment of the acid leaching process of a representative sample of electric arc furnace dust (EAF dust) and characterization of a representative sample were performed. As EAF dust is globally defined as hazardous solid industrial waste, and it contains a high percentage of zinc and other useful components, in this paper, the application of pretreatment will be carried out in order to increase the efficiency of the further process of acid leaching, all with the aim of using EAF dust as a secondary raw material for metal valorization. The pretreatment involved the application of a simple process of leaching the EAF dust sample with distilled water. Under the following defined optimal leaching conditions: time—30 min, ratio of solid to liquid phase—1:10, temperature—ambient, and stirring speed—500 rpm, a reduction in the content of water-soluble components was achieved, namely, 83% Cl, 92% K, 74% Na, 14% Cd, 15% Ca, and 19% F. The application of the pretreatment enables significantly better filtration of the suspension and increases the leaching efficiency of zinc and other useful components in the further process of leaching EAF dust with a sulfuric acid solution, compared with the process of direct acid leaching of EAF dust. [ABSTRACT FROM AUTHOR]

To solve the environmental pollution problem caused by the accumulation of bulk industrial solid wastes, the current research state on the preparation of mullite materials from industrial solid wastes was summarized. The preparation of mullite materials from alumina-rich and silica-rich industrial solid wastes was analyzed and summarized. The main problems encountered were pointed out, and the future develop-ment direction was looked forward. [ABSTRACT FROM AUTHOR]

The aim of this article is to reduce the environmental harm caused by industrial solid waste, specifically tannery sludge, and enable its reutilization. This study prepared an alkali-activated tannery sludge–slag solidification product (ATSSP) with high mechanical properties using blast furnace slag and tannery sludge as raw materials. The response surface methodology (RSM) was used to optimize the product mix ratio. The hydration mechanism and solidification method of ATSSP for Cr in tannery sludge were studied using X-ray diffraction (XRD), scanning electron microscope-energy dispersive spectrometer (SEM-EDS), and Fourier transform infrared reflection (FT-IR). The results indicate that the compressive strength regression model established through RSM has high accuracy and credibility. When the ratio of activator to binder is 0.2174, the alkali activation modulus is 1.02, and the water-to-cement ratio is 0.37; the 28 d compressive strength of ATSSP can reach 71.3 MPa. The sulfate in tannery sludge can promote the secondary hydration reaction of slag, and the generated hydrated calcium silicate and calcite greatly improve the strength of the ATSSP. The reducing substances contained in slag can reduce Cr (VI) in tannery sludge to Cr (III) in the form of uvarovite. The total Cr and Cr (VI) precipitation concentrations of the product are far less than the specification requirements. [ABSTRACT FROM AUTHOR]

• CO 2 mineralization ability was investigated by typical alkaline solid wastes. • The mineralization products of steel slag present excellent effect on plant growth. • The promotion of plant cultivation was analyzed from the view of mass transfer. CO 2 mineral sequestration using alkaline solid waste (ASW) is a promising strategy for synergistically reducing CO 2 emissions and reusing industrial waste. However, improvement the carbonation degree still remains challenges due to the sluggish leaching rate of Ca/Mg ion at low pH. To the issues, this study proposed an amine-mediated CO 2 absorption and mineralization process with six common ASWs, as well an ecological utilization route of CO 2 -ASW productions. Experimental results indicated that calcium carbide slag (CS) had greater CO 2 mineralization capacity (86.2 g-CO 2 /kg-CS) than other ASWs, while stirring rate and particle size played a more important role during CO 2 capture. Amine-mediated CO 2 capture was verified to be more excellent with steel slag (SS) as mineral medium. When the MEA concentration was increased to 2 mol/L, the extraction efficiency of Ca2+ was increased by 35 %, leaded to the CO 2 removal efficiency significantly promoted from 49 % to 92 %. The characterization of structural morphology referred spherical aragonite or needle-bar calcite was dominant for the porous mineralization products (30.6 m2/g). High germination index of pea seed (112.1 % at a dose of 10 g/L) inferred the negligible toxicological effects of tiny MEA residue over SS mineralization products, after centrifugally washing treatment. Pea seeds cultivated with mineralized products after centrifugal washing can achieve a growth rate of about 4 mm/d. Overall, this work provides a feasible route to apply the porous CO 2 -ASWs production into water conservation in arid and sandy land. [ABSTRACT FROM AUTHOR]

The continuous growth of industrial solid waste production has generated many environmental problems. We evaluated the potential of industrial solid waste as a substitute filler in asphalt mastic, with the aim of increasing the use of sustainable road construction materials. In this study, X-ray fluorescence spectroscopy (XRF) and scanning electron microscopy (SEM) were used to characterize the oxide composition and micromorphology of limestone (LS), red mud (RM), steel slag (SS), and ground granulated blast-furnace slag (GGBFS). Four asphalt mastics containing LS, RM, SS, and GGBFS with a filler-to-binder weight ratio of one were prepared. An evaluation of the rheology and wetting of the solid-waste-filler asphalt mastic was conducted using a frequency sweep, temperature sweep, linear amplitude sweep (LAS), multiple stress creep and recovery (MSCR), and surface free energy (SFE) methods. The results showed that SS increased the complex modulus, elastic component of the asphalt mastic and decreased the nonrecoverable creep compliance at stress levels of 0.1 and 3.2 kPa, which improved the rutting resistance of the asphalt mastic and reduced deformation under high-temperature conditions. The RM and GGBFS increased the fatigue performance of the asphalt mastic under strain loading, enhanced its fatigue life, and maintained good performance under long-term loading. The dispersive component of the SFE parameter of the solid-waste-filler asphalt mastic was larger than the polar component for the largest share of the surface energy composition. The SFE of the asphalt mastic prepared from the industrial solid-waste filler was reduced; however, the difference was insignificant compared to the limestone asphalt mastic. Solid-waste-filler asphalt mastic has performance characteristics, and its actual application can be based on different performance characteristics to select an appropriate solid-waste filler. The results of this study provide new technological solutions for solving the utilization rate of solid waste materials and sustainable road construction in the future. [ABSTRACT FROM AUTHOR]

With the increasing accumulation of alkaline industrial solid waste, the mineralization of CO2 using alkaline industrial solid waste has broad application prospects. Carbide slag is highly alkaline and contains a large amount of calcium elements, making it an excellent material for CO2 mineralization. Our idea was to acquire qualified products and fast kinetics by integrating carbide slag utilization and carbon reduction. The reaction route was divided into two steps: calcium extraction and carbonization. In order to achieve efficient extraction of utilizable calcium, we selected NH4Ac as the extraction agent, which has the advantage of buffer protection and environmental friendliness due to being an acetate radical. The extraction efficiency of utilizable calcium exceeded 90% under the conditions of L/S 20:1 and NH4+/Ca2+ 2:1. In the carbonization process, the crystal forms of CaCO3 synthesized by direct carbonation, acid extraction, and ammonium salt were characterized. The formation mechanism of vaterite in ammonium solution and the influence of impurities (Al3+, Mg2+) on the crystal transformation were revealed. This study provides technical support for using alkaline industrial waste to prepare high-purity vaterite. Therefore, alkaline industrial waste can be efficiently and sustainably utilized through CO2 mineralization. [ABSTRACT FROM AUTHOR]

Based on relevant data from 2014 to 2018, this research first evaluates the efficiencies of the industry production stage and environmental treatment stage via the dynamic two-stage SBM recycle model. Second, it employs the two-stage ZSG-SBM recycle model to optimize the allocation of resource usage and pollutant recovery variables of different provinces of China in 2025 according to the national plan, so as to find a path to realize the policy document goals of Made in China 2025. The empirical results show that the efficiencies of the east, central, and west regions nearly show a downward trend, and that two-level differentiation in the central region is large. In order to meet the planning requirements, the eastern provinces need to adjust and emit the least amount of carbon dioxide emissions per unit of industrial added value. [ABSTRACT FROM AUTHOR]

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In minority areas of Yunnan, China, the ecological environment is fragile, and social and economic development is not sufficient. The research on the evolution of human-earth systems can provide scientific guidance for solving the contradiction between environmental protection and social and economic development and promoting high-quality regional development. In this study, based on the structural division of the human-earth system, we established a comprehensive evaluation model by the data envelopment analysis (DEA) to analyze the evolution characteristics and influencing factors of the man-earth system in minority areas of Yunnan in terms of the coordinated development degree and the comprehensive efficiency of the system. The results show that: (1) From 1995 to 2020, the coordinated development degree of the human-earth system in minority areas of Yunnan showed an overall upward trend, with the average value rising from 0.31 in 1995 to 0.74 in 2020. (2) The average comprehensive efficiency of inputs and outputs of the human-earth system showed a downward trend; in particular, after 2007, the number of regions with ineffective DEA gradually increased, indicating that the development model of high inputs and consumption has not been effectively changed. (3) By calculating the system indicator weights using the entropy method, we found that the comprehensive utilization rate of industrial solid waste, total foreign trade and urbanization rate greatly impacted the coordinated development efficiency of the human-earth system in minority areas of Yunnan. [ABSTRACT FROM AUTHOR]

In order to improve the comprehensive utilization rate of industrial solid waste and the road quality, a novel low-carbon and environmental friendly soil stabilizer is proposed. In this study, steel slag (SS), carbide slag (CS), blast furnace slag (BFS), fly ash (FA), and desulfurized gypsum (DG) were used as raw materials to develop a multiple industrial solid waste-based soil stabilizer (MSWSS). The optimal mix ratio of the raw materials determined by D-optimal design was as follows: 5% SS, 50% CS, 15% BFS, 15% DG, and 15% FA. The 7-day unconfined compressive strength (UCS) of MSWSS-stabilized soil was 1.7 MPa, which was 36% higher than stabilization with ordinary portland cement (OPC) and met the construction requirements of highways. After 7 days of curing, the UCS of MSWSS-stabilized soil was significantly higher than that in the OPC group. X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) analysis indicated that the prominent hydration products were ettringite (AFt) and C-S-H gel. The results showed that an amount of AFt and C-S-H were formed in the initial stage of curing, resulting in a rapid improvement in early UCS. As the curing proceeded, the content of AFt and C-S-H increased constantly and grew intertwined with each other, which lead to the denser microstructure of stabilized soil and better mechanical strength. [ABSTRACT FROM AUTHOR]