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Sewage sludge management for fertilizer purposes can be a step in the circular phosphorus (P) economy. Using microbial solubilization in manufacturing fertilizers from recycled materials is an innovative approach with the potential to increase P compounds’ bioavailability, and fertilizers from sewage sludge ash and P-solubilizing bacteria are promising products of this technology. In addition to P and a range of macronutrients, these fertilizers contain small amounts of micronutrients and potentially toxic elements. This paper discusses the effects of fertilizer on iron (Fe) and aluminum (Al) content in soil, test plants (spring or winter wheat; grain and straw), weeds and post-harvest residues, based on field experiments. Treatments with conventional P fertilizers (superphosphate, phosphorite) and without P fertilization provided references. The tested biofertilizers containing the Bacillus megaterium or Acidithiobacillus ferrooxidans strain had no effect on total Fe and Al content in the soil or on the concentration of these elements in plant biomass when applied at P doses up to 35.2 kg ha–1. Fe and Al levels in grain did not suggest a potential risk to consumers.

Reinforced concrete based on ordinary Portland cement (OPC) is one of the most commonly used materials in modern buildings. Due to the global growth of the building industry, concrete components have been partially or completely replaced with waste materials that can be used as binders or aggregates. Besides the ecological aspects, modern architecture widely needs materials to make the concrete durable, resisting large loads and various detrimental forces in the environment. This opens the possibilities of managing waste materials and applying them in practice. This paper presents a concise review of the green solutions for ecofriendly materials in the building industry that deal with the practical application of materials commonly treated as waste. The main emphasis was placed on their influence on the properties of the building material, optimal composition of mixtures, and discussion of the advantages and disadvantages of each of the “green” additives. It turned out that some solutions are far from being ecofriendly materials, as they leech and release numerous harmful chemicals into the environment during their presence in concrete. Finally, the paper suggests a research direction for the development of an ecofriendly structural material for a sustainable future.

The article analyzes the structure of production of cereals in the country, it is established that during the processing of grain into grains a significant part of secondary material resources (flour and husk) is formed. Therefore, it is important to use husk of cereals as raw material for biofuel production. Different methods of producing organic solid biofuels have been analyzed, and it is shown that there are shortcomings of finished products - briquettes and pellets obtained without the use of binders, one of which is the problem of transportation over long distances, during which a considerable amount of compressed biofuel is destroyed due to an increase in humidity and, consequently, a decrease in their calorific values. Fuel pellets are mainly produced without addition, while for the production of briquettes with improved quality indicators, various additives and binders are used. The purpose of the work is to substantiate the complex technology of the processing of the waste of grain mills into pressed products. Object and object of research are formulated for achievement of the set goal. The object of research is the technological process of processing of waste of cereal mills, the regimes of certain technological processes, in particular preparation of binders. The subject of research is barley and barley husk, binders (barley glue). The use of starchy raw material - flour is suggested and grounded as a binder. On the basis of experimental studies, it has been proved that the most effective method is to prepare a paste of barley flour with a content of 15% CP followed by its introduction into biofuels in the amount of 5%. The article suggests and substantiates the complex technology of processing of cereal-based waste products into pressed products (fodder mixtures and biofuels), which includes the following technological lines: a pipeline preparation line; line of preparation for the binders; line of preparation of macro components; granulation line; briquetting line. The fuel pellets produced by this technology will have 1.13 kg / m3, fragility up to 10%. The scheme of the technological process of complex processing of cereal-based waste products into pressed products is presented. The principal technological scheme for the production of a granulated feed mixture or fuel pellets of feed is a holistic system within which the subsystems A, B, B, G1, D are interconnected. The principal technological scheme for the production of briquetted biofuels is a holistic system within which interconnections' The subsystems A, B, B, G, E function functioning seamlessly.

The article presents a schematic diagram of obtaining the components of technological and boiler fuels from polymer raw materials represented by materials from low and high pressure polyethylene, polypropylene and polystyrene. This scheme is based on the process of non-catalytic thermal destruction of raw materials in a batch reactor and consists of a section for preparation of raw materials, a section for thermal destruction as well as the fractionation of the resulting products. The given scheme on an industrial scale, depending on the properties of the raw material, makes it possible to obtain 10-20% (mass) of the fraction - 200°C, 30-50% (mass) of the 200-360°C fraction and 20-30% (mass.) fractions (> 360°C). Among the by-products, 3.0-5.0% (mass) light hydrocarbon gases (0.5-1.0 mass %) and the coke residue are formed. According to their properties, the obtained liquid products can be used as components for the production of process and a boiler fuel or as additives to improve the low-temperature properties of commercial fuels. [ABSTRACT FROM AUTHOR]

The case-law of the Court of Justice of the European Union (CJEU) has had a crucial impact on the development of the EU law. In particular, the role of CJEU case-law has been emphasized in relation to paradigm shifts in the EU. Currently the EU is aiming to transition to a circular economy by 2050. The drive towards a circular economy is based on the recognition that currently the world's natural resources are used to excess and inefficiently. Waste management and in particular the regulation governing the transformation of waste back into raw materials plays an integral role in the circular economy. This article examines the CJEU case-law on the concept of waste and its implications towards circular economy from 1980s to the modern today. It shows that the case-law has had a crucial role in the development the concept of waste and the rules for excluding secondary materials from it. The article concludes that the CJEU's powers are emphasized when a regulatory regime is in transition. Moreover, the circular economy regulatory environment is prone to generating numerous preliminary rulings. The importance of reconciling the objectives of the waste, product and chemicals regulation will be emphasized in the future. A natural continuation in the case-law would entail a gradual transition to a single regime for the regulation of materials and their flow. The CJEU could play an important role in the transition to the circular economy. [ABSTRACT FROM AUTHOR]

Recycling polymer waste is a great challenge in the context of the growing use of plastics. Given the non-renewability of fossil fuels, the task of processing plastic waste into liquid fuels seems to be a promising one. Thermocatalytic conversion is one of the methods that allows obtaining liquid products of the required hydrocarbon range. Clays and clay minerals can be distinguished among possible environmentally friendly, cheap, and common catalysts. The moderate acidity and the presence of both Lewis and Brønsted acid sites on the surface of clays favor heavier hydrocarbons in liquid products of reactions occurring in their pores. Liquids produced with the use of clays are often reported as being in the gasoline and diesel range. In this review, the comprehensive information on the thermocatalytic conversion of plastics over clays obtained during the last two decades was summarized. The main experimental parameters for catalytic conversion of plastics according to the articles’ analysis, were the reaction temperature, the acidity of modified catalysts, and the catalyst-to-plastic ratio. The best clay catalysts observed were the following: bentonite/spent fluid cracking catalyst for high-density polyethylene (HDPE); acid-restructured montmorillonite for medium-density polyethylene (MDPE); neat kaolin powder for low-density polyethylene (LDPE); Ni/acid-washed bentonite clay for polypropylene (PP); neat kaolin for polystyrene (PS); Fe-restructured natural clay for a mixture of polyethylene, PP, PS, polyvinyl chloride (PVC), and polyethylene terephthalate (PET). The main problem in using natural clays and clay minerals as catalysts is their heterogeneous composition, which can vary even within the same deposit. The serpentine group is of interest in studying its catalytic properties as fairly common clay minerals.

The recovery of valuable metals from different types of wastes has become of prime strategic interest given the scarcity of primary critical raw materials at international scale. Implementation of new methods or refinement of classical techniques with modern technological advances is, therefore, an active research field. Mine wastes are of special interest because their high metal concentrations make them environmentally harmful and economically profitable at the same time. In this study, we evaluated two different methods of Cu recovery from extremely acidic mine waters seeping from wastes and abandoned mines in SW Spain. Through a series of different batch experiments, we compared the method efficiency and crystallographic properties of elemental copper (Cu[0]) obtained by reduction of Cu2+ ions by (1) chemical reduction using ascorbic acid at different environmental conditions of pH (1.50–3.95), temperature (25–80 °C) and ascorbic acid concentration (10 mM to 0.1 M), and (2) classical cementation method with scrap iron at pH 1.50 and 25 °C. Our study demonstrates that the precipitation of Cu[0] can take place at pH 3.95 and low AA concentrations (0.1 M), resulting in large (µm-scale), perfectly developed crystals of copper with pseudoprismatic to acicular habit after 24 h of aging, likely through formation of a transient compound consisting in Cu2+-ascorbate and/or cuprite (Cu2O) nanocolloids. Reduction experiments at higher AA concentrations (0.1 M) showed faster precipitation kinetics and resulted in high-purity (>98%) copper suspensions formed by subrounded nanoparticles. The AA method, however, yielded very low recovery rates (15–25%) because of the low pH values considered. The cementation method, which produced tree-like aggregates formed by sub-micron crystals arranged in different directions, proved to be much more efficient (>98% recovery) and cost-effective.

The potential use of steel slag from treated steel slag in belite-sulfoaluminate cements was investigated in this study. Cement clinkers with two phase compositions were synthesized, allowing the incorporation of different amounts of steel slag. The phase composition and microstructure of cement clinkers at three different sintering temperatures were studied by X-ray powder diffraction and the Rietveld method, as well as scanning electron microscopy with energy dispersive spectrometry. The results showed that the targeted phase composition of clinkers was achieved at a sintering temperature of 1250 °C. However, a higher amount of perovskite instead of ferrite was detected in the clinker with a higher content of Ti-bearing bauxite. Apart from the main phases, such as belite, calcium sulfoaluminate, and ferrite, several minor phases were identified, including mayenite, perovskite, periclase, and alkali sulfates. In both clinker mixtures, a higher content of MgO in the steel slags resulted in the formation of periclase. Furthermore, the hydration kinetics and compressive strength at 7 and 28 days were studied in two cements prepared from clinkers sintered at 1250 °C. As evidenced by the results of isothermal calorimetry, the hydration kinetics were also influenced by the minor clinker phases. Cement with a higher content of calcium sulfoaluminate phase developed a higher compressive strength. [ABSTRACT FROM AUTHOR]

An overview of the ways of improving the operational properties of furnace and boiler fuels has been presented; their positive and negative features have been analyzed. It has been established that the most effective way to improve the operational properties of furnace and boiler fuels is their compounding with additives as well as various components since it is easy to implement under conditions of direct application of process fuel. It has been suggested that a very successful alternative to the additives and components used in industry can be fractions (components) obtained by thermal destruction in the temperature range of 300-380°C of secondary polymer raw materials, represented by polyethylene, polypropylene, and polystyrene. [ABSTRACT FROM AUTHOR]

Responsible production and consumption requires firms, political decision-makers and consumers to adapt to durable practices. Adapting a circular economy helps us achieve this objective, but in industries like the textile and fashion ones, due to the impact their companies have on the environment, responsible management of waste and usage of secondary raw materials should be part of their business model. In this paper we have sought to highlight through a few examples of good practices the role and impact that one of the major players within this industry, namely the H&M Group, has, through initiatives and innovations, on the transition towards a circular business model. [ABSTRACT FROM AUTHOR]

This geospatial dataset provides a compilation of findings from an evidence-based review of site-specific resource assessments of mining and metallurgical residues. Information pertaining to location, target material, geological knowledge, extractability, resource classification and stakeholder perspectives was collected from publicly available reports, articles, academic theses, and databases. The dataset includes 44 relevant data attributes from 64 mining and metallurgical sites in 27 countries. Resource classification is available for 38 sites. The dataset can be used by evaluators of recovery projects, authorities that provide permits, as well as by decision makers in support of developing regulatory policies. The dataset facilitates future addition of sites by the research community and can be further used as a starting point to bridge the estimates on recoverable quantities to the United Nations Framework Classification (UNFC). The UNFC is a universally applicable scheme for the sustainable management of all energy, primary and secondary mineral resources. Its use is stimulated by the European Commission and is intended to be adopted by geological surveys to harmonize the data on the availability of primary and secondary raw materials in Europe in future., (© 2024 The Authors. Published by Elsevier Inc.)

This work focused on the recovery and application of bioactive and functional compounds (BFC) from a waste matrix, the Opuntia ficus-indica (L.) Miller fruit peel (OFP), using different extraction methods: maceration and Extractor Naviglio®. The presence of BFC was initially evaluated by following the extraction yields and antioxidant activity using the Folin-Ciocȃlteu reagent and the DPPH method, respectively. The quali-quantitative content of BFC was also verified with UHPLC/UV-ESI-HRMS profile of OFP extracts. The evaluation of the BFC yields is aimed at using extract components, such as betanins, in the technological application as textile dye based on natural pigments: we evaluated the stability of the extracted dyes, tested the dyeing power and assessed the stability of the dye on the textile material. The results showed different compositions depending on the polarities of the solvents. The ethanol-water mixture extracts obtained using Naviglio method revealed an important presence in terms of total phenolic compound yields. Wool, linen and cotton fibers were chosen for the dyeing tests. Rock alum and lemon juice, two etching methods, were used. Results suggest that the OFP may be of great interest as a natural source of BFC for food, nutraceutical and technological applications in the sustainability context.

Environmentally sustainable cement mortars containing wheat straw (Southern Italy, Apulia region) of different length and dosage and perlite beads as aggregates were prepared and characterised by rheological, thermal, acoustic, mechanical, optical and microstructural tests. A complete replacement of the conventional sand was carried out. Composites with bare straw (S), perlite (P), and with a mixture of inorganic and organic aggregates (P/S), were characterised and compared with the properties of conventional sand mortar. It was observed that the straw fresh composites showed a decrease in workability with fibre length decrease and with increase in straw volume, while the conglomerates with bare perlite, and with the aggregate mixture, showed similar consistency to the control. The thermal insulation of the straw mortars was extremely high compared to the sand reference (85–90%), as was the acoustic absorption, especially in the 500–1000 Hz range. These results were attributed to the high porosity of these composites and showed enhancement of these properties with decrease in straw length and increase in straw volume. The bare perlite sample showed the lowest thermal insulation and acoustic absorption, being less porous than the former composites, while intermediate values were obtained with the P/S samples. The mechanical performance of the straw composites increased with length of the fibres and decreased with fibre dosage. The addition of expanded perlite to the mixture produced mortars with an improvement in mechanical strength and negligible modification of thermal properties. Straw mortars showed discrete cracks after failure, without separation of the two parts of the specimens, due to the aggregate tensile strength which influenced the impact compression tests. Preliminary observations of the stability of the mortars showed that, more than one year from preparation, the conglomerates did not show detectable signs of degradation.

Flotation wastes are becoming a valuable secondary raw material and source of many metals and semimetals worldwide with the possibilities of industrial recycling. The flotation tailings contain oxide and sulfide minerals that have not been sufficiently stabilized and form acidic mine waters, which in turn contaminate groundwater, rivers, and reservoi6sediments. An effective way to recycle these mine wastes is to recover the metals through leaching. While the focus is on acid bioleaching by iron- and sulfur-oxidizing bacteria, alkaline leaching, and the removal of iron-containing surface coatings on sulfide minerals contribute significantly to the overall environmental efficiency of leaching. For this study, static and percolate bioleaching of copper from flotation waste at the Bor copper mine in Serbia was investigated in alkaline and then acidic environments. The aim of the study was to verify the effect of alkaline pH and nutrient stimulation on the bioleaching process and element extraction. A sample was taken from a mine waste site, which was characterized by XRF analyses. The concentration of leached copper was increased when copper oxide minerals dissolved during alkaline bioleaching. The highest copper yield during alkaline bioleaching was achieved after 9 days and reached 67%. The addition of nutrients in acidic medium enhanced the degradation of sulfide minerals and increased Cu recovery to 74%, while Fe and Ag recoveries were not significantly affected. Combined bioleaching with alkaline media and iron- and sulfur-oxidizing bacteria in acidic media should be a good reference for ecological Cu recovery from copper oxide and sulfide wastes.

The aim of this paper is for the production of oils processed in refineries to come from the pyrolysis of real waste from the high plastic content rejected by the recycling industry of the Basque Country (Spain). Concretely, the rejected waste streams were collected from (1) a light packaging waste sorting plant, (2) the paper recycling industry, and (3) a waste treatment plant of electrical and electronic equipment (WEEE). The influence of pre-treatments (mechanical separation operations) and temperature on the yield and quality of the liquid fraction were evaluated. In order to study the pre-treatment effect, the samples were pyrolyzed at 460 °C for 1 h. As pre-treatments concentrate on the suitable fraction for pyrolysis and reduce the undesirable materials (metals, PVC, PET, inorganics, cellulosic materials), they improve the yield to liquid products and considerably reduce the halogen content. The sample with the highest polyolefin content achieved the highest liquid yield (70.6 wt.% at 460 °C) and the lowest chlorine content (160 ppm) among the investigated samples and, therefore, was the most suitable liquid to use as refinery feedstock. The effect of temperature on the pyrolysis of this sample was studied in the range of 430–490 °C. As the temperature increased the liquid yield increased and solid yield decreased, indicating that the conversion was maximized. At 490 °C, the pyrolysis oil with the highest calorific value (44.3 MJ kg−1) and paraffinic content (65% area), the lowest chlorine content (128 ppm) and more than 50 wt.% of diesel was obtained.

The mineral raw materials’ resource efficiency is currently recognized in Europe as the way for the future development of the European mining economies. With this aim, a West Balkan Mineral Register was created in the EIT Raw Materials RESEERVE Project, including Primary and Secondary Raw Materials of six Eastern and South-Eastern Europe (ESEE) countries, i.e., Albania, Bosnia and Herzegovina, Croatia, Montenegro, North Macedonia, and Serbia. Within the Project, a Strengths, Weaknesses, Opportunities, and Threats (SWOT) and Gap Analysis was also performed for the development of the raw material sector in the region. This paper summarizes the main strengths to be exploited, i.e., the significant geological potential, the presence of critical raw materials (e.g., Sb, Co, REEs) in primary and secondary raw materials, and the challenges to address, i.e., compliance of resources/reserves classification with international standards, integration of state’s mineral policy with spatial planning strategies, improvement of the business environment, capacity building of the raw materials workforce and enhancement of the public acceptance of the sector, in order to achieve the sustainable development of the mineral resources of the six ESEE countries. These opportunities comply with the objectives of the EU Raw Materials Initiative and are expected to contribute in the further enhancement of those economies in transition for the upcoming years.

Featured Application: The aim of this investigation is a simple and easily adaptable agglomeration process for the different quantities and qualities of EAF by-products. The costs and need of disposal for these by-products will be omitted if internal, on-site recycling is possible. In addition to the blast furnace converter route, electric steel production in the electric arc furnace (EAF) is one of the two main production routes for crude steel. In 2019, the global share of crude steel produced via the electric steel route was 28%, which in numbers is 517 million metric tons of crude steel. The production and processing of steel leads to the output of a variety of by-products, such as dusts, fines, sludges and scales. At the moment, 10–67% of these by-products are landfilled and not recycled. These by-products contain metal oxides and minerals including iron oxide, zinc oxide, magnesia or alumina. Apart from the wasted valuable materials, the restriction of landfill space and stricter environmental laws are additional motivations to avoid landfill. The aim of the Fines2EAF project, funded by the European Research Fund for Coal and Steel, is to develop a low-cost and flexible solution for the recycling of fines, dusts, slags and scales from electric steel production. During this project, an easy, on-site solution for the agglomeration of fine by-products from steel production has to be developed from lab scale to pilot production for industrial tests in steel plants. The solution is based on the stamp press as the central element of the agglomeration process. The stamp press provides the benefit of being easily adapted to different raw materials and different pressing parameters, such as pressing-force and -speed, or mold geometry. Further benefits are that the stamp press process requires less binding material than the pelletizing process, and that no drying process is required as is the case with the pelletizing process. Before advancing the agglomeration of by-products via stamp press to an industrial scale, different material recipes are produced in lab-scale experiments and the finished agglomerates are tested for their use as secondary raw materials in the EAF. Therefore, the tests focus on the chemical and thermal behavior of the agglomerates. Chemical behavior, volatilization and reduction behavior of the agglomerates were investigated by differential thermogravimetric analysis combined with mass spectroscopy (TGA-MS). In addition, two melts with different agglomerates are carried out in a technical-scale electric arc furnace to increase the sample size. [ABSTRACT FROM AUTHOR]

• WEEE were used as secondary raw material to produce gold nanoparticles. • Gold was selectively extracted from microprocessors by hydrometallurgical methods. • Nanoparticles synthesis was developed according to the obtained Au (III) solution. • Obtained nanoparticles are pure, stable and can be used as optical sensors. One of the current challenges in circular economy is the ability to transform waste into valuable products. In this work, waste of electrical and electronic equipment (WEEE) was used as a gold source to prepare stable gold nanoparticles (AuNP). The proposed methodology involves a series of physical and chemical separation steps, carefully designed according to the complex nature of the selected WEEE and the targeted product. In a first step, pins from microprocessors were separated by mechanical treatments, allowing to concentrate gold in a metallic fraction. A two-step hydrometallurgical method was subsequently performed, to obtain a Au (III) enriched solution. Such solution was used as a secondary raw material to obtain AuNP. For that purpose, a specific synthetic method was developed, adapted to the high acidity and ionic strength of the solution. Thanks to the use of two easily available reducing agents (sodium citrate and ascorbic acid) and a polymeric stabilizer (PVP), it was possible to obtain high purity AuNP presenting a mixture of well-defined spherical and triangular shapes. These AuNP were finally deposited onto glass substrates and present a sensitive response to refractive index changes in the environment, a necessary condition towards application in optical sensors. In summary, this upcycling case study demonstrates that e-waste can successfully replace primary raw materials to obtain highly valuable and useful nanomaterials. These results highlight the potential of urban mining as a sustainable and circular approach to the development of nanotechnologies. [ABSTRACT FROM AUTHOR]

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The textile system is one of the most influential production activities at a global level from an environmental point of view, both in relation to the processes that characterize the supply chain and in relation to pre- and post-consumer waste. It produces million tons of global greenhouse gas emissions per year and it consumes millions of liters of water; it uses million tons of chemical products. Furthermore, millions of tons of special textile wastes are yearly landfilled. Less of 1% of materials used to produce clothes becomes part of a closed-loop recycling and less of 2% are recycled in other industrial activities. Changing the textile industrial linear model in a circular one according to Systemic Design principles is advisable, starting from wastes and by-products. As proved in the working paper wastes can assumed as inputs of new production systems. Particularly the scientific contribution deals with some research activities carried out within a project titled EDILTEX - Innovation for reusing in textile companies. The achievements are described, showing that construction and fashion are fields only apparently far from each other. They can - on the contrary - developing powerful synergies and products with interesting technological and physical performances. [ABSTRACT FROM AUTHOR]

The diversity of molecules with different functionalizations allows targeting of various end products, such as biomaterials, biobased plasticizer, food additives and fertilizer. The heterogeneity of organic municipal solid waste (OMSW) streams, however, challenges the formulation of reliable statements regarding the share of functionalized molecules. The aim of this study was the assessment of OMSW as source of functionalized molecules when hydrolysis was carried out enzymatically, thermo-chemically as well as thermo-chemically and enzymatically. Results revealed that OMSW is only quantitatively assessable at carbohydrate, protein and lipid levels. This is due to a changing seasonal and spacial composition, and consequently different hydrolytic products. However, also the treatment had an impact on the quantity. Depending on the treatment 230–640 mg g−1 carbohydrates, 150–250 mg g−1 lipids and 80–200 mg g−1 proteins were quantified in food waste and organic street waste. The intensity of treatment had an impact on the quality of sugars. When wastes were treated enzymatically glucose, fructose and sucrose were found. Using thermochemical treatment glucose can be the only product. Contrarily, lipid and fatty acid as well as protein contents seemed not affected by the treatment. [ABSTRACT FROM AUTHOR]

Copyright of Annual Set the Environment Protection / Rocznik Ochrona Środowiska is the property of Koszalin University of 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.)

Copyright of Journal of Global Economics / Revista de Economie Mondială is the property of Institute for World Economy 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.)

Red Mud (RM) is a byproduct of the Bayer Process, used to extract alumina from bauxite. This residue contains valuable metals and rare earth elements (REEs), which can be bioleached under acidic conditions and later recovered, eventually reducing the RM pollution potential. The focus of this study was to extract metals through bioleaching using biostimulated biomass. A sequencing batch reactor (SBR) was operated at two different solid to liquid ratios (S/L, 2% and 1.5%) under aerobic conditions, using a feeding strategy based on pH evolution over time. The lowest pH obtained at 2% S/L was 3.8. Metals extraction efficiencies were 68 ± 18% for Mn, 58 ± 4.5% for Mg, 51 ± 2.9% for Al, 0.6 ± 0.07% for Ti and < 0.1% for Fe. At 1.5% S/L, a slightly lower pH was achieved (3.4), with metals extraction efficiencies similar to those obtained at 2% S/L, but more stable over time. At 1.5% S/L, REEs (i.e., Nd, Ce, Y, Sc and La) extraction efficiencies were also evaluated, and the highest value was obtained for Nd (around 65%). The results were promising and provided useful information for further enhancing the efficiency of metals extraction, in the perspective of process scale-up. • Bioleaching of valuable metals and REEs from red mud was achieved in an SBR. • Biomass was properly stimulated and naturally enriched without inoculum addition. • Significant extraction efficiencies for Al, Mg, and Mn were obtained. • Promising extraction efficiency of around 65% was reached for Nd. • Similar extraction results were obtained at 2% and 1.5% S/L. [ABSTRACT FROM AUTHOR]

• Pioneering valorization of sulfidic mine tailings into cold-bonded granules. • Minimal heavy metal leaching endorses safe use in second-life applications. • Granule content versus concrete performance (workability, strength and durability). Repurposing sulphidic tailings in construction products offers a sustainable solution for this mining waste. Aggregates (1–4 mm and 2–8 mm) were produced at pilot scale using cold granulation with minimal cement content (6 wt% CEM III/B + 94 wt% tailings). Superplasticizer dose was optimized in mortar and concrete mixes replacing 17 % and 32 % of natural aggregates. The concretes benefit from the additional buffering capacity from cement hydrates in granules (relevant for carbonation and chloride penetration), but their increased porosity lower freeze–thaw resistance. Cement-based mixes offer a sustainable solution for this waste in applications with moderate or non-structural requirements. [ABSTRACT FROM AUTHOR]

Waste materials and industrial by-products are increasingly used in the production of cement clinker and cement, serving as secondary fuels, secondary raw materials, and supplementary cementitious materials. As these waste-derived materials are partially or fully incorporated into the product, they are technically recycled. Consequently, a certain proportion of the cement consists of recycled materials. This paper presents a method to calculate this recycled content in cement not only based on mass streams, but also based on valuable chemical components and compares the results for both calculation methods in the course of a case study of two Austrian cement plants. It is demonstrated that one metric ton of cement consists of 365 kg and 387 kg of secondary materials, respectively. This results in an average recycled content of 37.6 %. In addition, the contribution of primary and secondary materials to the heavy metal content of cement is assessed. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper presents a process where carbon fibers and hydrogen can be recovered simultaneously through a two-stage thermal treatment of an epoxy-carbon fiber composite. For this purpose, some pieces of epoxy resin reinforced with carbon fiber fabrics have been fabricated and, after curing, have been pyrolyzed in an installation consisting of two reactors. In the first one, the thermal decomposition of the resin takes place, and in the second one, the gases and vapors coming from the first reactor are thermally treated. Once this process is completed, the solid generated is oxidized with air to eliminate the resin residues and carbonaceous products from the fibers surface. The recovered carbon fiber fabrics have been reused to make new cured parts and their electrical and mechanical properties have been measured. The results show that it is possible to obtain carbon fiber fabrics that can be processed as they leave the recycling process and that retain 80% of the tensile modulus, 70% of the flexural strength, and 50% of the interlaminar shear strength. At the same time, a gaseous stream with more than 66% by volume of hydrogen can be obtained, reaching a maximum of 81.7%.

The objective of this study was to investigate the valorization potential of clayey overburden sterile materials from lignite-mining activities in the manufacturing of traditional ceramics. This study aims to contribute toward the sustainable management and use of such waste materials in line with the environmental objectives of the 2030 agenda. To assess this issue, clayey steriles were incorporated in a white clay-body at 20, 50, and 80 wt%, whereas reference samples were also formed from the individual raw materials. Laboratory processing of the ceramics was performed by dry pressing loose powder into rectangular samples and firing at 1000 °C for 4 h. Characterization of the raw materials included chemical, mineralogical, and thermal analysis. The fired bodies were tested for their total linear shrinkage, apparent porosity, water absorption, bulk density, and bending strength according to the relevant standards. The microstructural evolution of the final bodies was analyzed by scanning electron microscopy, which observed differences related to the addition of the steriles. The results showed that the tested clayey steriles can be utilized up to 50 wt% as a secondary raw material in the production of ceramic materials (e.g., bricks) with comparable properties to the reference clay-bodies. Furthermore, the color of the final samples changed from white-creamy to reddish as the content of clayey sterile materials increased in the raw mix.

Phosphorus (P)-rich secondary raw materials can provide a valuable base for modern mineral fertilizers, provided that the new formulations do not load the soil–plant system with potentially toxic elements. Fertilizers from sewage sludge ash (SSA) and/or animal bones, activated by phosphorus-solubilizing bacteria (Bacillus megaterium or Acidithiobacillus ferrooxidans), were tested in field experiments in north-eastern Poland. The reference provided treatments with superphosphate and treatment without phosphorus fertilization. In one experiment, all P-fertilizers were applied at a P dose of 21 kg·ha−1, and in the other three experiments, three P doses were adopted: 17.6, 26.4, and 35.2 kg·ha−1. The effect of recycled fertilizers on the content of arsenic (As), chromium (Cr), nickel (Ni), copper (Cu), and zinc (Zn) in the soil, in wheat grain and straw (test plant), weeds, and post-harvest residues was investigated. The application of recycled fertilizers in P amounts up to 35.2 kg·ha−1 did not change the As, Cr, Ni, Cu, or Zn contents in the soil and plant biomass. The contents of these elements in soil were below the permissible levels for arable land in Poland. Their concentrations in wheat grain and straw did not exceed the permissible or suggested limits for plant material to be used for food and feed, while in the weed and post-harvest residue biomass, they usually fell within the biological plant variability ranges.

One of the largest industrial waste water pollutants is petroleum products. The most widely used physico-chemical cleaning methods (use of sorbents) are used for cleaning them, but the main difficulty is the selection of suitable sorbents (different according to their origin and structure) and maintenance of op-tidal treatment facilities. The production of sorbents from secondary raw materials reduces the amount of waste and, at the same time, protects nature against hazardous materials, for example from used car tires. Three different sorbent species (organic organic sorbents – branched lead, synthetic sorbents – zeolites, sorbents made of atrium raw materials – crushed used tires) have been evaluated and compared. The changes in the concentrations of oil products in the wastewater before and after treatment procees were evaluated and compared. The initial concentration of oil products in waste water was 0.25 mg/m3. Experimental studies show that the maximum adsorption capacity is 2.90 g/g (fraction 1.00−1.50 mm) of zeolite 2.55 g/g (fraction 2 mm), and 1.97 g/g The crushed tire rubber (fraction 1.00−1.50 mm) has adsorption capacity similar to that of a trimmer. The efficiency of the separa-tion of ceolite (fraction 2.00 mm) ranged from 87.51% to 96.11%, and the straw burners from 91.30% to 94.55%, and the crushed tire rubber shavings (fraction 1.00−1, 50 mm), the purification efficiency ranged from 91.51% to 95.21%. Santrauka Vienais didžiausių gamybinių nuotekų teršalų laikomi naftos produktai. Jiems valyti plačiausiai naudojami fizikiniai ir cheminiai valymo metodai (sorbentų naudojimas), bet pagrindinis sunkumas – tinkamų sorbentų (skirtingų savo kilme ir struktūra) parinkimas ir optimalių valymo sąlygų įrenginiuose palaikymas. Gaminant sorbentus iš antrinių žaliavų, mažinamas atliekų kiekis ir kartu saugoma gamta nuo pavojingųjų medžiagų, pavyzdžiui, nuo naudotų automobilių padangų. Darbe įvertinta ir palyginta trijų skirtingų sorbentų rūšių sorbcinė geba (natūralių organinių sorbentų – siauralapio švendro; sintetinių sorbentų – ceolitų; sorbentų, pagamintų iš atrinių žaliavų – susmulkintų panaudotų padangų), nustatyti naftos produktų nuotekose koncentracijų pokyčiai prieš valymo procesą ir po jo. Pradinė naftos produktų koncentacija nuotekose siekė 0,25 mg/m3. Atlikti eksperimentiniai tyrimai rodo, kad didžiausia adsorbcinė geba yra ceolito − 2,55 g/g (frakcija 2 mm), susmulkintų padangų gumos – 2,01 g/g (frakcija 1,00–1,50 mm) ir siauralapio švendro – 1,97 g/g. Susmulkintų padangų gumos (frakcija 1,00–1,50 mm) adsorbcinė geba panaši į ir siauralapio švendros. Ceolito (frakcija 2,00 mm) išvalymo efektyvumas kito nuo 87,51 % iki 96,11 %, o siauralapio švendro – nuo 91,30 % iki 94,55 %, o susmulkintų padangų gumos drožlių (frakcija 1,00–1,50 mm) išvalymo efektyvumas kito nuo 91,51 % iki 95,21 %. Reikšminiai žodžiai: antrinės žaliavos, naftos produktai, padangų gumos drožlės, nuotekų valymas, sorbentai.

The purpose of the paper is to analyze on micro level the stream of building materials needed for raising cattle. The scope of the produced material flow chart will cover the inflow and storage of the materials. The overall objective of material flow analysis is to contribute to the data inventory development process which is needed to use these construction materials as secondary raw materials in the future. The assessment is based on a concrete new development in a Hungarian region being carried out nowadays as a development and modernization of an existing cattle raising farm. Driven by the concern of resource depletion, further research on higher level, based on larger database will be needed to verify the estimated national level results for the magnitude of growth of anthropogenic stocks.

Waste problems that cannot be solved by simple procedural adjustments or improvements in practices require more substantial long-term changes. It is necessary to develop possible prevention options for the waste problems, but also, several policies regarding the re-using materials or using the recycled materials are necessaries. In this sense, the concept of the raw materials substitution implies effective and efficient use of raw materials in scope to minimize losses along the process system, as well as using different raw materials that will not generate waste during the manufacturing processes. This concept also further implies re-using materials or using recycled materials. In this way, the natural resources should be used in the most efficient way. Recycled waste can be returned back into the economy as secondary raw materials, thereby achieving the full potential of these materials. [ABSTRACT FROM AUTHOR]

Based on various statistical data and calculations, the article analyzes the load of the secondary raw material collection system in Lithuania, distinguishes territorial regularities. A more detailed analysis of the survey results, the existing municipal waste management policy and the organization of the secondary raw material collection system indicate possible causes of territorial differentiation, also taking into account socio-economic assumptions. [ABSTRACT FROM AUTHOR]

The use of secondary raw materials in metallurgical processes such as steelmaking is an important contribution to the circular economy aspired to by EU members and many other countries. The agglomeration of dusts, fines and sludges is an important pretreatment step to enable the use of these materials in subsequent melting processes, such as steelmaking in electric arc furnaces (EAFs). It also reduces the amount of by-products and waste materials that are currently waste for disposal and are landfilled. The presented research is part of the Fines2EAF project, which aims to increase the value of steelmaking residues by internal recycling and use or reuse in the form of agglomerates. The approach followed in this project is the use of a hydraulic stamp press and alternative binder systems to produce cement-free agglomerates. The first results of lab-scale agglomeration tests of six different recipes with varying pressing forces are presented in this paper. It is shown that the addition of fibres from paper recycling has a strong effect on the cold compression stability of the agglomerates, by far exceeding other effects such as increased pressing force. Overall, the agglomerates produced in the lab show promising characteristics, for example, cold compression stability and abrasion resistance, which should allow for use in EAF steelmaking. [ABSTRACT FROM AUTHOR]

Prevention and mitigation of acid rock drainage (ARD) from mine wastes are crucial for limiting environmental impact. However, preventive measures are often too expensive, potentially harmful to the environment or not applied early enough. This study aimed to test the potential of different secondary raw materials for maintaining a circumneutral pH (6–7) in a sulfide oxidation environment, allowing secondary minerals to form on reactive sulfide surfaces to prevent release of acid, metals and metalloids, and thereby ARD generation. Five materials (blast furnace slag, granulated blast furnace slag, cement kiln dust, bark ash, lime kiln dust) were selected based on their alkaline properties, availability and yearly yield. High sulfidic (>50 wt%, sulfide) waste rock from an active Cu–Zn–Au–Ag open pit mine in northern Sweden was leached in small-scale laboratory test cells under ambient condition for 4–8 weeks before adding secondary raw materials on the surface in an attempt to prevent ARD generation. During 52 subsequent weeks of leaching, the pH and electrical conductivity in the leachate from the waste rock varied between 1.7-4.6 and 2.1–22.8 mS/cm, respectively. All secondary raw materials were able to increase the pH to circumneutral. However, blast furnace slag, granulated blast furnace slag and cement kiln dust were not able to maintain a circumneutral pH for an extended time due to self-cementation or carbonation, whereas bark ash (1 wt%) and lime kiln dust (5 wt%) prevented acidity, metal and metalloid leaching. Materials such as cement kiln dust and bark ash contained elevated concentrations of, e.g., Cd and Zn, but the release of metals and metalloids was generally low for most elements, except for Cl, K and Na, most likely due to salt dissolution. • Addition of secondary raw materials decreased metal and metalloid concentrations. • Lime kiln dust maintained a circumneutral pH throughout leaching. • Salt dissolution had a negative effect on the leachate quality. [ABSTRACT FROM AUTHOR]

The authors established the chemical and phase compositions of grain fractions of the magnesia carbon scrap disintegrated using industrial cone crushers. The investigations included chemical and XRD analyses and optical investigations. The contents of admixtures: SiO2, CaO, Fe2O3 and Al2O3 increase with the decreasing size of the scrap grain fractions, whereas the C/S ratio decreases in finer and finer fractions due to changes of the phase composition. These relations are caused by the presence of low-fusible silicate phases, characterized by their cleavage and brittleness. Such phases were mainly derived from the graphite ash containing a high silica content. The scrap after removing its finest grain fractions can be recycled and utilized for producing the magnesia-carbon refractory materials. However, the finest grain fractions may be used, e.g. as a component of gunite mixes. Many years of experience collected by the arcelorMittal Refractories Ltd., krakow, Poland in the field of refractory scrap utilization has also been presented. [ABSTRACT FROM AUTHOR]

The paper presents the results of research on the application of recycled tyre rubber, in the form of rubber dust, in mixtures bound with a hydraulic binder, to improve the physical and mechanical parameters of unburnt coalmining slates. In particular, the parameters related to resistance to water and susceptibility of bound mixtures. The research was carried out on mixtures containing unburnt coal-mining slate, rubber dust, fly ash and cement, as well as on reference mixtures with no rubber dust in their composition. The observations were aimed at checking how the varied content of rubber dust affects the physical and mechanical parameters of the samples. [ABSTRACT FROM AUTHOR]

Facing phosphate rock scarcity, growing food requirements and pollution problems with phosphorus (P)-containing waste, re-using P as fertiliser is becoming a real need. Innovative fertilisers from sewage sludge ash, animal bones and blood, activated by phosphorus solubilising microorganisms (PSM), were tested in field experiments with winter or spring wheat and compared with commercial fertilisers (superphosphate, phosphorite). Three levels of P doses were established (17.6, 26.4 and 35.2 kg/ha). This paper discusses the fertilisers' impact on total soil P content and on the P content and P accumulation in wheat grain and straw, weeds and post-harvest residues. Recycled fertilisers maintained soil P stocks and supplied plants with P in the same way as traditional fertilisers, and ensured a comparable P pool in the post-harvest residues to traditional fertilisers. They also did not favour weeds during competitive crop-weed interactions. The PSM included in waste-fertilisers did not exert an evident effect on the soil P content or on the P content and P accumulation in plant biomass. The findings show the potential of recycled fertilisers to act as a substitute to fertilisers from primary sources. Further field research is needed to settle the question of the reasonability of PSM inclusion into fertilisers. [ABSTRACT FROM AUTHOR]

Abstract Poor storage of industrial wastes has been a cause of land contamination issues. These wastes or by-products have the potential to be used as secondary raw materials in construction, promoting the concept of a circular economy that will avoid land contamination. Here we evaluate radiological environmental impacts when wastes that contain elevated levels of naturally occurring radionuclides (NORs) such as red mud, fly ash and ground granulated blast furnace slag are made into 'green cements' such as geopolymers or alkali-activated materials (AAMs). During the study, three AAM concrete and mortar series with various mixing ratios were prepared and investigated. The NOR content, I-Index, radon emanation and exhalation of the precursor waste materials and their cement products were measured and calculated and the strength of the cement products was compared. The emanation and the exhalation properties were calculated for the final products, weighing the data of the components as a function of their mixing ratio. The I-index alone suggested that the AAMs would be suitable products. AAMs containing ground granulated blast furnace slag exhibited the lowest radon exhalation and higher compressive strength, while the fly ash and red mud AAMs had increased final radon exhalation. In the case of fly ash, alkaline activation of fly ash dramatically increased the radon exhalation; the highest measured fly ash exhalation was 1.49 times of the theoretically calculated exhalation value. This highlights the increased risk of using fly ash as a component in AAMs and the need to carry out testing on the final products as well as individual secondary raw materials. Graphical abstract Unlabelled Image Highlights • Three alkali-activated materials were prepared using secondary raw materials. • The radiological properties of the secondary raw materials and AAMs were determined. • The fly ash content increased the radon exhalation during alkali activation. • Increasing GGBFS content resulted in better radiological and strength property. [ABSTRACT FROM AUTHOR]

• Solar panels can be effectively dismantled by Electro-Hydraulic Fragmentation (EHF). • Both crushing and EHF produce a wide fraction distribution between <0.25 to >4 mm. • Crushing followed by sieving results in a high level of metals in all fractions. • EHF and sieving concentrates metal elements into two main fractions <0.5 and >4 mm. • Over 98% of Cu in a PV panel is found in the >4 mm fraction produced by impulse EHF. Currently, the first generation of solar panels are reaching their end-of-life, however so far, there is no best available technology (BAT) to deal with solar panel waste in terms of the optimized circular economy of metals. In this brief communication, electro-hydraulic fragmentation (EHF) is explored as an initial conditioning stage of photovoltaic (PV) modules to facilitate the recovery of valuable metals with the main goal to produce liberated fractions that are suitable for the retrieval of materials like Si, Ag, Cu, Sn, Pb, and Al. When compared to traditional crushing, the results suggest that dismantling of PV panels using EHF shows more selectivity by concentrating metals among well-defined particle size fractions. Using this method, the subsequent recovery of metals from PV panels can be achieved in a straightforward manner by simple means like sieving. The fragmentation achievable with EHF technology allowed approximately 99% Cu, 60% Ag, 80% of Pb, Sn and Al total elemental weight within the solar panels to be concentrated solely within the >4 mm size range, whereas high purity (>99%) Si could be found in the fractions between >0.50 mm and <2 mm. To the best of the authors' knowledge, this paper presents for the first time a comparative analysis on the use of EHF technique and conventional crushing for the processing of PV solar panel waste. [ABSTRACT FROM AUTHOR]

Biotechnological processing of secondary raw material resources of the oil and fat industry in useful products is the most expedient and effective in terms of both economic and environmental requirements. The obtained experimental results of the study indicate the prospect of lipolysis with the lipase Rhizopus japonicus fat fraction of waste generated during the hydrogenation of vegetable oils. The greatest activity in relation to olive oil is expressed by lipase Rhizopus oryzae. Lipase Rhizopus japonicus exhibits the highest activity relative to hydrogenated fat, which is explained by its substrate specificity. It was found that the content of free fatty acids in the hydrolyzate reached the saturation level after 72 hours of hydrolysis, and the concentration of triglycerides during this time of hydrolysis decreased to a minimum value. The results of research should be used to improve the processing technology of waste oil and fat industry in the food industry. [ABSTRACT FROM AUTHOR]

The market interest in ornamental rocks commercially referred to as "stones" has grown significantly in recent years, particularly regarding basalt. This has resulted in the widespread use of diamond wire equipped with sintered diamond beads for precision sawing in basalt quarries, especially those located in the industrialized countries; it also has the advantage of preventing rock damages. Diamond wire has been widely used in up-line cutting and other sawing works in both marble and granite quarries for decades; therefore, performance data about the use of this tool on these two different types of rocks are widely documented in academic literature. However, for basalt sawing, information pertaining to the use of diamond wire is unavailable due to various reasons, but mostly because of to its relatively recent introduction in the basalt quarries and also to the historical low market demand for processed basalt in the past. This study offers a possible solution to this lack of information and provides a technical, economic and environmental assessment of diamond wire used in quarrying basalt for ornamental purposes. After an overview on the state of the art of diamond wire and on the final use of processed basalt, the study describes the experimental plan and the results. These show a tool yield much higher than those measured when diamond wire is used on other silicate dimension stones (e.g. granites). Moreover, the composition of basalt sawdust (sludge) has been analysed in the laboratory and has indicated the absence of polluting materials related to tool wear; therefore, basalt sludge, which is made of water and micronized basalt, can be used as a secondary raw material for the environmental restoration of the area or for any other purpose. Further research on other lithotypes is also proposed. [ABSTRACT FROM AUTHOR]

The article shows the advantages of production of fodder mixtures from the waste of grain mills, the reasons for reducing the production of feed mixtures, problems in grain processing enterprises, which are due to the lack of efficient waste disposal. The production of solid biofuels from secondary material resources (flour and husk) has been proposed. Different methods of producing solid organic biofuels are analyzed, and it is shown that there are deficiencies in finished products such as briquettes and pellets obtained without the use of binders, one of which is the problem of transporting over long distances, during which a considerable amount of compressed biofuel is destroyed at the expense of increasing humidity and, consequently, reducing their calorific value. Fuel pellets (pellets) are mainly produced without the addition of binders, while for the production of briquettes with improved quality indicators, various additives and binders are used. Theoretical and experimental researches substantiated the component composition of paled-in granules, determined the physical properties of finished products. It is suggested and grounded as a CR to use starch-based raw material -a flour. On the basis of experimental studies, it has been proved that the most effective method is to prepare a paste of barley flour with a content of dry substances of 15 %, followed by its introduction into biofuels in the amount of 5 %. The article suggests and substantiates the complex technology of the processing of the production of grain mill products into pressed products (fodder mixtures and biofuels), which includes the following technological lines: a pipeline preparation line; line of preparation for the CL; line of preparation of macro components; granulation line; briquetting line. Fuel pellets resulting from this technology will have a density of 1.13 t/m3, fragility up to 10 %. The principal technological scheme of obtaining granulated feed mixture and fuel pellets is given. The developed integrated technology of waste processing of crushed plants is universal, does not require significant investments and will allow not only efficiently to process secondary raw materials, to get rid ofproblems with their utilization, but also by way of organizing recycling at the industry enterprises to solve both energy and environmental problems. [ABSTRACT FROM AUTHOR]

One of the largest industrial waste water pollutants is petroleum products. The most widely used physico-chemical cleaning methods (use of sorbents) are used for cleaning them, but the main difficulty is the selection of suitable sorbents (different according to their origin and structure) and maintenance of op-tidal treatment facilities. The production of sorbents from secondary raw materials reduces the amount of waste and, at the same time, protects nature against hazardous materials, for example from used car tires. Three different sorbent species (organic organic sorbents - branched lead, synthetic sorbents - zeolites, sorbents made of atrium raw materials - crushed used tires) have been evaluated and compared. The changes in the concentrations of oil products in the wastewater before and after treatment procees were evaluated and compared. The initial concentration of oil products in waste water was 0.25 mg/m3. Experimental studies show that the maximum adsorption capacity is 2.90 g/g (fraction 1.00-1.50 mm) of zeolite 2.55 g/g (fraction 2 mm), and 1.97 g/g The crushed tire rubber (fraction 1.00-1.50 mm) has adsorption capacity similar to that of a trimmer. The efficiency of the separation of ceolite (fraction 2.00 mm) ranged from 87.51% to 96.11%, and the straw burners from 91.30% to 94.55%, and the crushed tire rubber shavings (fraction 1.00-1, 50 mm), the purification efficiency ranged from 91.51% to 95.21%. [ABSTRACT FROM AUTHOR]

The potential use of steel slag from treated steel slag in belite-sulfoaluminate cements was investigated in this study. Cement clinkers with two phase compositions were synthesized, allowing the incorporation of different amounts of steel slag. The phase composition and microstructure of cement clinkers at three different sintering temperatures were studied by X-ray powder diffraction and the Rietveld method, as well as scanning electron microscopy with energy dispersive spectrometry. The results showed that the targeted phase composition of clinkers was achieved at a sintering temperature of 1250 °C. However, a higher amount of perovskite instead of ferrite was detected in the clinker with a higher content of Ti-bearing bauxite. Apart from the main phases, such as belite, calcium sulfoaluminate, and ferrite, several minor phases were identified, including mayenite, perovskite, periclase, and alkali sulfates. In both clinker mixtures, a higher content of MgO in the steel slags resulted in the formation of periclase. Furthermore, the hydration kinetics and compressive strength at 7 and 28 days were studied in two cements prepared from clinkers sintered at 1250 °C. As evidenced by the results of isothermal calorimetry, the hydration kinetics were also influenced by the minor clinker phases. Cement with a higher content of calcium sulfoaluminate phase developed a higher compressive strength.

The reasons of low level of involvement of secondary resources in commercial use in the Russian Federation are studied. It is revealed that the existing system for the treatment of household solid waste in the region is an inseparable waste collection, transport for disposal or temporary placement of waste, which in most cases act as places of long-term storage. The absence of a process for sorting and separation of useful component leads to an increase in the amount of waste and spent funds for the disposal of solid waste. It is noted that the main tasks and perspective directions of development of system of management in the sphere of household solid waste management for Volgograd agglomeration are as follows: maximum use of separate collection of solid household waste to obtain secondary resources and the reduction of the volume of disposed waste; use of the latest technologies for processing solid waste into secondary materials that will allow returning them to the components in the production cycle; remediation of closed landfills and the elimination of illegal dumping, which will reduce the area they occupy and their negative impact on the environment; the optimal operation of the existing solid waste landfills based on subsequent reclamation; and the collection of secondary raw materials; construction waste sorting facilities for processing of solid waste and enterprises for processing of secondary raw materials. The primary objective in the management of solid waste for the near future is to optimize their collection and disposal (at a constant long-term strategy for the transition from the field of disposal of solid waste their industrial processing).