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This is an article in the field of ceramics and composites. Taking ilmenite ore as the research object, the possible phase transformation of FeTiO3 in concrete liquid phase environment was analyzed in order to provide a basis for the utilization of ilmenite tailings. The thermodynamic stability of ilmenite (FeTiO3) was analyzed by thermodynamic calculation. Ilmenite ore powder was soaked in simulated concrete pore solution at 20 ℃ and 80 ℃ for 28 d and 270 d, XRD and SEM/EDS were used to detect mineral transformation. Using ilmenite ore to replace part of the gravel to prepare concrete, the influence on concrete strength at 20 ℃ and 80 ℃ was studied respectively. The results of thermodynamic calculations show that FeTiO3 is unstable in the environment of O2 and converts into Fe3O4 or Fe2O3 and TiO2. The immersion experiment of ilmenite in the simulated concrete pore solution shows that ilmenite has no obvious changes. The concrete strength test shows that at 20 ℃ and 80 ℃, when ilmenite ore replaces 5% crushed stone, the compressive strength of concrete increases, and when the replacement is 15%, the compressive strength decreases, the reason is that the quartz in the ilmenite ore has undergone an alkali aggregate reaction.

This is an article in the field of ceramics and composites. Attapulgite is an important mineral resource with high utilization value. It is widely used in agriculture, environment, materials, chemical industry, biology, catalysis and other fields. It has abundant reserves in China and has good development prospects. At present, the utilization rate of attapulgite is still low, and a large number of attapulgite has not been effectively developed. This article analyzes and summarizes the current situation of separation, purification and application of attapulgite domestic and abroad.The mineralogical characteristics and crystal structure characteristics of attapulgiteare briefly described. The genetic types, resource distribution, mineral reserves, and ore types and physical and chemical properties of attapulgite are summarized. The current research status of attapulgite separation and purification, the methods and research progress of attapulgite surface modification, the application status of attapulgite in mineral functional materials are inductively described. Based on the current research content, the problems that appeared in the research process are analyzed and new ideas and directions for the research and application of attapulgite are proposed.

This is an article in the field of ceramics and composites. In order to improve the comprehensive utilization of mineral resources and mining technology, mine filling materials are prepared from mineral solid wastes such as phosphogypsum, cement and tailing sands as aggregates, analytical studies of the slurry's comprehensive search performance, mineral composition and microscopic morphology are carried out, and the molecular structure of hydrides is discussed in conjunction with molecular dynamics simulations. The results showed that the addition of phosphogypsum significantly increased the slump of the modified filler, decreased the bleeding rate, and the compressive strength showed a rising trend. The strength value of the modified filler increased significantly with the curing time. The strength of phosphogypsum modified backfill after curing for 28 d is about 1.2 times that of cement backfill. Calcium silicate hydrate and ettringite in phosphogypsum modified filling materials are the main hydration products. SEM image shows that the microstructure of phosphogypsum modified filling materials is relatively compact and there are few micro-cracks. The numerical simulation results show that the elastic modulus of calcium silicate hydrate is higher than that of ettringite. The key to improving the strength of filling material is to promote the formation of calcium silicate hydrate.

This is an article in the field of inorganic non-metallic materials.To achieve comprehensive utilization of fly ash and sintering red mud, this study uses fly ash as the main raw material, sintering red mud as an auxiliary material, and sodium hydroxide as an alkaline activator to synergistically prepare geopolymer. The results showed that the optimal preparation conditions for geopolymer were as follows: fly ash was pretreated with a classification pretreatment (extraction of fine fraction), with a graded particle size of 37 μm. The mass ratio of fine-grained fly ash to sintering red mud is 7∶3 (g∶g), and the dosage of NaOH accounts for 15% of the mass of the precursor powder. The compressive strength of the geopolymer prepared at these conditions reached 35.52 MPa after curing at room temperature for 28 d, meeting the strength standard of 32.5R slag portland cement in the Common Portland Cement of China. The raw materials and geopolymers prepared at different pretreatment methods were analyzed and tested using XRF, XRD, ICP-OES, and SEM-EDS. The test results showed that compared to mechanical grinding, classification pretreatment can effectively improve the reactivity of fly ash, allowing more active silicon and aluminum components to participate in geopolymerization reactions. The addition of sintering red mud can promote the formation of calcium-rich aluminosilicate gel and densify the microstructure of geopolymers. This study provides new insights into the comprehensive utilization of fly ash and sintering red mud.

This is an article in the field of ceramics and composites. Influence of the mixed mineral powder content and proportion on the performance of concrete were studied. The results show that with the continuous increase of the proportion of mixed slag powder, the strength of the mixed slag powder concrete shows a change rule that first increases and then decreases. And the maximum value is achieved when the ratio of compound ore powder is 1∶2. Under the effect of the same number of freeze-thaw cycles, the mass loss rate of concrete shows a trend of first decreasing and then increasing with the increase of the proportion of mixed mineral powder. However the relative dynamic elastic modulus of concrete shows a trend of first increasing and then decreasing. At the same measuring position, as the proportion of compound slag powder increases, the chloride ion content in the compound slag powder concrete shows a continuous decrease. And when the ratio is 1∶2, the chloride ion content of the mixed slag powder concrete decreases faster. The comprehensive test results show that the strength characteristics of limestone tailings concrete are the best when the content of limestone tailings is 20%. The strength and durability of concrete reach the best when the ratio of mixed mineral powder is 1∶2.

This is an article in the field of ceramics and composites. Vanadium extraction tailing from stone coal is a dangerous industrial waste. Comprehensive utilization of vanadium extraction tailings from stone coal has important environmental and economic significance. The fired bricks for building were prepared from the vanadium extraction tailings of stone coal. The effects of firing temperature on microstructure and properties were studied, and the leaching activity passivation mechanism of Cu, V, and Zn heavy metal was explored. The results showed that sintering temperature significantly affected the phase composition, microstructure and performances of sintered bricks. Properly increasing the firing temperature was not only in favour of silicon-rich liquid phase generation to increase the density of samples by the reaction between quartz and alkaline element in raw materials, but also contributed to anorthite transformation from melilite and the mullite formation. These crystalline phases bond with glass, endowing the product with high density and compressive strength. In addition, an increase in firing temperature improved the Cu, V, and Zn residual content in the product, reduced the pore size and volume, thus achieving the solidification of Cu, V, and Zn. With the 1 150 ℃ firing temperature and 3 h holding time, the properties of the sintered building bricks can meet the requirements of standard Mu25 in 《fired common bricks》(GB/T5101-2003). Cu, V, and Zn leaching concentrations in the product were below the standard values. This study provides a new insight for the efficient utilization of vanadium tailings from stone coal.

This is an article in the field of ceramics and composites. The mix proportion of limestone powder cement is designed based on the mixture design principle, and the effects of limestone powder content and particle size on the mechanical properties of limestone powder Portland cement system are studied. The hydrate phase and microporous structure of portland cement paste mixed with 0.44 mm and 0.025 mm limestone powder were analyzed by X-ray diffraction (XRD) and low field nuclear magnetic resonance (NMR). The results show that the two limestone powders have a negative effect on the early compressive strength. However, with the progress of hydration, limestone powder within a certain dosage range can enhance the later strength of cement. When the dosage exceeds this range, the compressive strength decreases gradually with the increase of dosage. Although the addition of limestone powder produces hydrated calcium carboaluminate in the hydration products which is conducive to the mechanical properties of cement stone, its coarsening of microporous structure greatly reduces the compressive strength of limestone powder cement specimens when the content of limestone powder exceeds a certain value.

This is an article in the field of ceramics and composites.The high-temperature sintering method was used to prepare foamed ceramics by using fly ash and blast furnace slag as the main raw materials, adding silicon carbide (SiC) as a high temperature foaming agent and sodium borate (Na2B2O7) as a flux. The effects of raw material ratio, SiC addition and Na2B2O7 addition on the bubble structure, bulk density, water absorption, compressive strength and thermal conductivity of foamed ceramics were mainly studied. The experimental results showed that when the fly ash was 70%, the blast furnace slag was 30%, 0.3% SiC powder and 5% Na2B2O7 were added additionally, and the sintering temperature was 1 100℃ for 40 min, the foamed ceramic had the best comprehensive properties, and its bulk density was 0.516 g/cm3, with water absorption rate of 3.82%, compressive strength of 3.62 MPa, thermal conductivity of 0.094 W/(m·K). The main phases of the sample under this condition included quartz phase (SiO2), anorthite (CaAl2Si2O8) and pyroxene phase (Ca(Mg,Al,Fe)Si2O6), the massive precipitation of crystals enhanced the strength of the material. This research provided a new method for converting industrial solid wastes such as fly ash and blast furnace slag into high value-added building insulation materials.

This is an article in the field of ceramics and composites. Alkali-activated Slag-fly Ash-based Geopolymer (ASFG) has excellent properties such as high early strength, acid and alkali resistance, but its large brittleness and poor toughness affect its popularization and application. In order to improve the properties of ASFG and broaden the types of mineral admixtures that can be used for ASFG modification, six kinds of mineral admixtures, including metakaolin, zeolite powder, bentonite, wollastonite powder, light calcium carbonate and silica fume, are used as modified materials, and their modification effects on ASFG are studied. The optimum modified material is silica fume. In order to further explore the improvement effect of silica fume on the mechanical properties of ASFG, the effect of the content of silica fume on the mechanical properties of ASFG is studied, and the optimal content of silica fume is determined. Finally, Alkali-activated Slag-fly Ash-silica Fume-based Geopolymer Concrete (ASFSGC) is prepared, and its workability, quasi-static mechanical properties and impermeability are studied. The results show that bentonite, wollastonite powder, light calcium carbonate and silica fume can significantly improve the flexural strength of ASFG. Wollastonite powder and silica fume can significantly improve the compressive strength of ASFG. For ASFG, silica fume is a premium mineral admixture. With the increase of silica fume content, the mechanical properties of ASFG first increase and then decrease, and the optimal content of silica fume is 4%. ASFSGC has good workability and excellent impermeability, and the ductility of ASFSGC is 14.1% larger than that of ordinary Portland cement concrete.

This is an article in the field of ceramics and composites. To achieve the resource utilization of fly ash and accurately assess the compressive strength of fly ash concrete, three predictive models for compressive strength were constructed using machine learning modeling techniques, including traditional linear regression, decision tree, and support vector machine models. These models were utilized to model and analyze the compressive performance of the concrete. Firstly, a corresponding experimental database was established, with seven input parameters including cement, fly ash, water reducer, coarse aggregate, fine aggregate, water, and curing age, and the compressive strength as the output parameter. Based on 10-fold cross-validation, the performance of the three models on the training set was evaluated using root mean square error (RMSE), mean absolute error, and correlation coefficient, and their performance on the test set was compared. The results showed that curing age had a high correlation with compressive strength (0.60), and the correlation of fly ash with compressive strength was higher than that of cement. The traditional linear regression model exhibited an RMSE of 7.27 and 5.91 on the training and test sets, respectively. The decision tree model showcased an RMSE of 2.72 and 9.23 on the respective sets, while the support vector machine model yielded an RMSE of 5.34 and 4.09. Overall, the support vector machine model exhibited good accuracy and robust performance in predicting the compressive strength of fly ash concrete. This research can provide strength design guidance for concrete using fly ash and promote the resource utilization of fly ash.

This is an article in the field of ceramics and composites. In order to explore a new way for the application of phosphogypsum in road materials, phosphogypsum powder and asphalt mortar were mixed to prepare phosphogypsum modified asphalt. The effects of mixing temperature, powder-binder ratio and polyphosphoric acid content on the three major indicators of phosphogypsum modified asphalt were studied. The research results show that the softening point increases as the mixing temperature increases, and the ductility increased first and then kept constant. Considering energy efficiency and aging temperature, the processing temperature of asphalt should be in the range 135 °C and 145 °C. increasing the powder gum ratio can increase the softening point of the modified asphalt and decrease the ductility of the asphalt. Therefore, the ratio of filler bitumen should not be greater than 0.9 using phosphogypsum as the modifier. The addition of polyphosphoric acid greatly increases the softening point of modified asphalt, but reduces its ductility and penetration. The optimal amount of polyphosphoric acid should be around 1.5%. Infrared spectroscopy (FTIR) and thermogravimetric analysis (TG-DSC) showed that phosphogypsum physically functioned with Asphalt. When polyphosphoric acid was mixed into asphalt, it would react chemically with asphalt. The research results could provide references for the engineering application and theoretical research of phosphogypsum in road materials.

This is an article in the field of ceramics and composites. In this article, the effects of IOT and polyvinyl alcohol (PVA) fiber (PF) on the compressive strength, four-point flexural strength, flexural toughness, pore structure of cement-based composites were studied and discussed in detail. The conversion relationship between compressive strength and four-point flexural strength was established. The results showed that the incorporation of IOT had an enhanced effect on the mechanical properties, and this enhanced effect showed a trend of first increasing and then decreasing with the increase in the substitution rate of IOT. However, when PF was added, the mechanical properties under the combined effect of PF and IOT were further improved and showed good toughness. In addition, the internal pores of the matrix with IOT substitution rate of 40% and PF were obviously reduced. Thus, it was concluded that the cement-based composite material had good mechanical properties when the 40% IOT was combined with PF.

This is an article in the field of ceramics and composites. The performance of asphalt mixtures with different iron tailings content was analyzed. The rutting resistance, water stability and crack resistance of the asphalt mixture were analyzed. This verified the feasibility of iron tailings applied to the middle surface of low-grade roads. The results showed that the flexural strength decreased the most when the dosage was from 20% to 40%. The increase rate of immersion residue stability began to decrease after the dosage was 20%. As the content of iron tailings continued to increase, the FT-IR spectrum of iron tailings asphalt concrete showed a small, new absorption peak locally and an enhancement to the original absorption peak. This showed that after the addition of iron tailings, the asphalt concrete chemically reacted with it, and the internal structure of the original asphalt was changed and new functional groups were generated. With the increasing content of iron tailings, the proportion of the area of cycloalkane and alkane C-H functional groups in the asphalt concrete of iron tailings asphalt concrete showed a trend of first increasing and then decreasing. And when the iron tailings content was 20%, the area ratio of asphalt naphthenic and alkane C-H functional groups reached the maximum.

This is an article in the field of ceramics and composites. Hydroxyapatite (HAP) has excellent ion exchange performance, shows good adsorption capacity for heavy metal ions, harmful anions, and organics in wastewater, and will not cause secondary pollution in the process of wastewater treatment. Thus, it is a promising green adsorbent. Due to its small size and large specific surface area, nano-hydroxyapatite (nHAP) exposes more adsorption sites, showing supreme adsorption capacity. It is a tendency to produce nHAP composites of strong adsorption capacity, easy for solid-liquid separation and regeneration, and low-cost. This article reviews the recent research progress of nano-HAP and its composites as adsorbents for wastewater treatment, and prospects the application of them as adsorbents.

This is an article in the field of ceramics and composites. In order to study the adsorption effect of modified bentonite on heavy metal ions in sewage, the effects of pH value, initial concentration, time, solid-liquid ratio, temperature and particle size on the adsorption effect of bentonite were analyzed. And microscopic means were used to study the changes of the internal mineral composition of the bentonite before and after the adsorption of heavy metal ions and the change law of the infrared spectra. The results showed that when the modified bentonite content was 0.2 g, the adsorption time was 1.5 h, the temperature was set to 40 ℃, the pH value was set to 6, the initial concentration was set to 200 mg/L and the solid-to-liquid ratio was set to 0.8 g/L, the adsorption effect was the best. After the modified bentonite had undergone an adsorption test, an obvious CuSO4 diffraction peak could be detected. However, other mineral components inside the modified bentonite remained unchanged, which also showed that the modified bentonite could effectively adsorb copper ions in sewage.

This is an article in the field of ceramics and composites. In order to effectively treat and resource utilize lateritic nickel slag, this study used lateritic nickel slags as raw materials and measured the pH value of leaching solution, metal leaching concentration, material unconfined compressive strength, dry shrinkage, elastic modulus, permeability coefficient and other indexes of the cementing material formed by cement solidification, and analyzed the feasibility of using it as backfill material for construction land or highway construction engineering materials. The results show that the cementitious material is made of waste slag (dry basis) 92%, PO42.5 cement 5%, bentonite 3%, PAC 0.5% and water, the pH value of leaching solution is about 8.45, the concentration of leaching metal ions is less than 0.1 mg/L, the unconfined compressive strength is 1.47 MPa, the modulus of elasticity is 1196 MPa, the permeability coefficient is 8.77×10-7 cm/s, and the dry shrinkage resistance is good. It can be used as backfill material for construction land or highway construction engineering. The raw soil cementitious material made of 92% raw soil (dry basis), 5% PO42.5 cement, 3% bentonite, 0.02% additional CHF and 5%～8% water has better dry shrinkage resistance. It can be used as the surface layer of large volume cementitious material to resist dry shrinkage cracks caused by long-term contact with dry air, protect the waste slag cementitious material in the lower layer and ensure the overall stability of cementitious materials. The above research provides a new way for the comprehensive utilization of laterite nickel slags, and lays a theoretical foundation for the research and engineering practice of waste slag as backfill materials or highway building materials.

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources 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.)

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources 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.)

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources 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.)

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources 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.)

This is an article in the field of ceramics and composites. Montmorillonite organic gel is a thixotropic gel, which is usually produced by wet process. It needs to be spray drying to obtain gel products. However, the drying cost accounts for the major part of the production cost due to the low efficiency and high energy consumption of spray drying. Therefore, it is of great importance to reduce the energy consumption in the process of dehydration. A new type of pre dehydration process with low energy consumption is proposed in this paper. A non-metallic mineral material with high specific surface area and good water absorption is filled into the dehydrated tank. The montmorillonite organic gel is injected into the dehydrated tank and stirred well to achieve the purpose of pre dehydration. The high-quality organic gel product is then obtained by spray drying. The special process for the pre-dewatering process is designed and the energy consumption of the pre-drying process and the spray drying process without pre dehydration are compared by thermal calculation. The results show that the pre dehydration process can save about 58% energy compared with the existing process.

This is an article in the field of ceramics and composites. In order to study the early rheological properties of alkali-activated fly ash-slag cementitious system, the composite pastes with different mass ratios of fly ash (FA) to slag (GGBS) and alkaline activator content were prepared. The fluidity and rheological properties of the pastes were tested by mini-cone slump cone, Brookfield DV3T rheometer,respectively. Finally, the hydration exothermic rate of composite pastes with each ratio was tested by isothermal calorimeter. Results show that when FA/GGBS ratio is 3∶7, the fluidity of paste with 4% NaOH content is the lowest. With the increase of FA mass ratio and NaOH molar mass, the fluidity of alkali-activated FA-GGBS cementitious system increased, and the yield stress and plastic viscosity decreased. The growth of FA content decreases the early hydration rate significantly, while the increase of alkali activator content remarkably increases the peak rate of hydration heat release.

This is an article in the field of ceramics andcomposites. C30 concrete was prepared with steel slag powder with different particle size as admixture, and the effect of steel slag powder particle size on the durability of concrete was studied. The test results show that the internal pores of concrete are mainly concentrated in 100~1000 nm, and the number of pores decreases with the refinement of steel slag powder, and the pores of about 10~100 nm increase with the refinement of steel slag. The addition of steel slag can improve the workability of concrete; With the continuous refinement of steel slag, the 7, 28 and 56 d compressive strength of concrete decreases first and then increases. The 56 d compressive strength decreases from 50.4 MPa to 37.8 MPa and continues to increase to 40.32, 42.84, 45.36 and 48.4 MPa. With the fineness of steel slag from 23.1 MPa decreases to 16.8、12.2、10.1、4.2 μm. The activity of m steel slag increased from 75% to 96%. After 100 freeze-thaw cycles, the mass loss of concrete without steel slag group is 7.6%. When 30% steel slag is added, the frost resistance of concrete decreases. With the change of steel slag fineness, the frost resistance of concrete increases continuously, when the fineness is 10.1、4.2 μm, the mass loss is reduced to 7.4% and 6.1%. The addition of steel slag can promote the solidification and storage capacity of concrete to CO2 and enhance the pressure strength of concrete. The finer the steel slag is, the stronger the carbonization resistance of concrete is.

This is an article in the field of ceramics and composites. Mechanical properties and durability of sodium sulfate solution corrosion of iron tailings concrete are developed. The effects of different iron tailings content, the number of dry and wet cycles, and the concentration of sodium sulfate solution on its mechanical properties and durability are analyzed. The results show that when the iron tailings content is 30%, the number of dry and wet cycles is 60 times, and the sodium sulfate concentration is 5%, the performance indicators of the concrete reach the best state. With the increasing amount of iron tailings, the better the corrosion resistance and frost resistance of concrete will be. The heat of hydration reaction is constantly decreasing. The porosity of concrete and the change of total mercury volume show a trend of first decreasing and then increasing. Under the same condition of iron tailings content, the change law of the main peak amplitude of concrete after corrosion shows an increasing trend. However, under the same sodium sulfate solution concentration, the main peak amplitude of concrete showed a trend of first decreasing and then increasing after corrosion.

This is an article in the field of ceramics and composites. Natural porous minerals have many environmental attributes, such as pore structure, surface effect, environmental hydration effect, ion exchange characteristics and good adsorption capacity. The natural porous minerals have good harmony with the earth's ecological environment and can be applied to agricultural fertilizers, soil reclamation, feed breeding and other aspects of agricultural production. Based on the environmental attributes of natural porous minerals and their mineral materials, researchers should pay attention to exploiting their special functions in agricultural production and agricultural ecological environment. The self-purification function of natural porous minerals is a potential function endowed by nature for the survival and development of the earth's environment. Its resource characteristics and environmental attributes are very suitable for the application conditions of soil remediation and green agricultural production in China. The research on using natural porous minerals in agricultural production has an important economic influence on society.

This is an article in the field of ceramics and composites. In order to explore the resistance of basalt fiber to acid and alkali corrosion, basalt fiber with or without wetting agent was soaked in 3 mol/L sulfuric acid solution and sodium hydroxide solution, respectively, and the mass loss rate, fracture force retention rate and SEM image of fiber surface were tested. The results showed that with the increase of soaking time, the mass loss rate of basalt fiber with infiltrating agent increased from 1.42% to 7.33%, the fracture force retention rate decreased from 95.34% to 66.49%, the mass loss rate of basalt fiber without infiltrating agent increased from 3.69% to 9.40% and the fracture force retention rate decreased from 88.39% to 53.64%. After soaking in sodium hydroxide solution, the mass loss rate of basalt fiber with wetting-agent increased from 0.40% to 5.41%, the fracture force retention rate decreased from 97.37% to 79.82%, the mass loss rate of basalt fiber without wetting-agent increased from 1.50% to 7.08%, and the fracture force retention rate decreased from 93.42% to 69.85%. Both acid-alkaline corrosion cause fiber quality loss, increase fiber surface defects and reduce fiber breaking force.Sulfuric acid solution with the same concentration corrodes basalt fiber more seriously than sodium hydroxide solution. The soaking agent has a protective effect on the fiber and can slow down the corrosion of acid and alkali on the fiber.

This is an article in the field of ceramics and composites. In order to improve the impermeability and microstructure of the impermeable wall materials, four kinds of calcium-based bentonite modified and filling material with different dosages were prepared under the action of alkali excitation reaction. The modified and filling material samples in the curing process were tested by flexible wall penetration (FWPT), nuclear magnetic resonance (NMR) scanning and electron microscope scanning (SEM). The results show that the permeability coefficient of filling material samples decreases first and then increases with the increase of bentonite content, and reaches a minimum value when the content of bentonite is 4%. The relaxation time (T2) distribution curves of the filled material specimens after curing from 1 to 28 d were all bimodal, with more than 80% of the peaks representing small pores, and the percentage of the peaks representing large pores decreasing with the increase of curing time. According to SEM images, it can be seen that a certain amount of calcium bentonite can promote the occurrence of hydration reaction, and the porosity of the material is significantly reduced. At 4% phosphate slag, the cementitious filler has the best compactness and better impermeability and strength. Accordingly, it can be determined that the better dosage of phosphate slag modified cementitious filler is 4%.

This is an article in the field of ceramics and composites. The changes of resistivity, compressive strength and chloride ion migration coefficient of concrete under different dosages are used to evaluate the durability of concrete. The impermeability, mechanical properties, and chloride ion corrosion resistance of concrete under the action of different iron tailings content and different fly ash content are studied. The effect of adding different proportions of iron tailings and fly ash on the performance of concrete is analyzed.The results show that the compressive strength of concrete reaches the maximum when the content of iron tailings and fly ash is 30%. However, the larger the proportion of fly ash and the smaller the proportion of iron tailings, the worse the compressive strength, impermeability and resistance to chloride ion corrosion of concrete. Therefore, in the actual preparation of concrete, a mixing ratio of a large amount of iron tailing sand and a small amount of fly ash should be used. With the increase in the content of iron tailings and fly ash, the hydration heat release rate and total heat release of iron tailings also show a decreasing trend under the same hydration time. This shows that the addition of iron tailings and fly ash greatly reduces the hydration heat release rate and total heat release of concrete. With the increase in the amount of iron tailings and fly ash, the pore size value corresponding to the peak point of the concrete pore size distribution curve is also increasing, but the increasing amplitude is getting smaller and smaller.

This is an article in the field of ceramics and composites. In order to improve the mechanical properties of concrete, basalt fiber is used to prepare torsional members of gangue concrete. The empirical formula is used to predict the elastic modulus of concrete with four kinds of basalt fiber content. Then, the finite element software is applied to carry out torsion numerical simulation of gangue concrete members and the empirical formula of ultimate bearing capacity is proposed. The results show that the error between the predicted elastic modulus and the measured one is relatively small. The torsion curves of the basalt fiber modified concrete members obtained by numerical calculation accord with the measured results of related tests. Adding basalt fiber into gangue concrete can significantly improve the bonding performance of concrete mortar, which thus strengthens the torsional resistance of concrete members.

This is an article in the field of ceramics and composites. Methylene blue is a typical pollutant industrial wastewater.It will bring great harm to the water body if it is discharged arbitrarily without treatment. We prepared a kind of attapulgite/nano iron composite (DDBAC/ATP/nZVI), that the attapulgite was roasted, organic modified and then loaded with nano iron (nZVI) by liquid-phase reduction. The optimum preparation process is obtained: attapulgite raw soil is calcined at 300 ℃ for 1.5 h, 20 mmol/100 g benzalkonium chloride(DDBAC)is added, then ultrasonic is used for 20 min, and then nano iron is loaded by liquid-phase reduction method. The ratio of iron to soil is 1:3, KBH4 concentration is 0.25 mol/L and reaction time is 3 h. The XRD, FTRI, SEM, XPS, BET confirm that DDBAC and nano iron are successfully loaded on the surface of attapulgite. The maximum removal of methylene blue by DDBAC/ATP/nZVI is 114.94 mg/g, and the application performance of the DDBAC/ATP/nZVI remains stable within 60 days.

This is an article in the field of ceramics and composites. In order to improve the performance of fly ash-based porous ceramic materials, the samples were surface-treated using Al2O3 modifying liquid, and physical and mechanical properties, adsorption effects and microscopic experiments were carried out on them. The results showed that the higher the sintering temperature, the smaller the porosity and water absorption of the porous ceramics, and the greater the strength and apparent density. Optimal sintering and molding of porous structures at a temperature of 1100 °C. When the concentration of Al2O3 modifying liquid was increased from 0 to 50 mol/L, the saturated adsorption rate of the porous ceramics increased about 6 times, and at the same time, the densities and strengths were also significantly increased. The surface modification effect of the Al2O3 modifying liquid promotes the formation of the caliche feldspar crystals, which results in a significant increase in the strength and adsorption properties of the porous ceramics. strength and adsorption performance were significantly improved.

This is an article in the field of ceramics and composites. In order to study the mechanical properties and durability of iron tailings concrete after being subjected to the dry-wet cycle of sodium sulfate solution, the compressive test, chloride ion corrosion test, frost resistance test and hydration characteristics test of the concrete eroded by sodium sulfate solution are carried out. The effects of different iron tailings content, number of dry and wet cycles, and solution concentration on the mechanical properties and durability of concrete are analyzed. The results show that when the iron tailings content is 30%, the number of dry and wet cycles is 60 times, and the sodium sulfate concentration is 5%, the mass loss rate of concrete is the smallest and the compressive strength and corrosion resistance coefficient is the largest. As the content of iron tailings continues to increase, the better the corrosion resistance and frost resistance of concrete will be and the heat of hydration reaction decreases.

This is an article in the field of ceramics and composites. In order to study the influence of diatomite content on the physical properties, rheological properties and road performance of asphalt mixtures, the basic physical tests, rheological tests, high temperature stability and low temperature crack resistance tests were carried out on asphalt mixtures under different diatomite content.The results show that when the diatomite content is 30%, the softening point, cone penetration and ductility of the asphalt mixture reach the maximum. When the diatomite content is 40%, the penetration of the asphalt mixture reaches the maximum. The law of change in ductility shows an increasing trend. The temperature is 170 ℃ as the preparation temperature of the asphalt mixture. The 30% diatomite content can be selected as the optimal value of low temperature crack resistance of asphalt mixture. At the same time, adding diatomite can effectively improve the high temperature performance of the asphalt mixture, but excessive incorporation of diatomaceous earth will weaken its high temperature performance. As the content of diatomite continues to increase, the variation of some characteristic peaks in the infrared spectrum of asphalt concrete shows a decreasing trend. During the aging process of asphalt concrete, its internal light components are affected by high temperature, and volatilization occurs. However, as the content of diatomite continues to increase, the characteristic peak-to-peak value of the light component of asphalt concrete after aging has not changed much.

This is an article in the field of ceramics and composites. Phosphogypsum has a large discharge and low utilization rate,and resource utilization is imminent. The heat treatment of phosphogypsum under different temperatures was studied. The influence of heat treatment temperature on the physical phase and microstructure of phosphogypsum, and the compressive strength, phase and microstructure of non burningsample of building materials by the treated phosphogypsum were studied. The results show that with the increase of heat treatment temperature, the crystallinity of gypsum increases and the crystal form changes. After heat treatment at 80 ℃, the crystal of gypsum is dense, and part of it is converted into hemihydrate gypsum. The Gypsum dihydrate formed by hydration recrystallization of hemihydrate gypsum fills the void, forming the internal microstructure of dense and mutual bonding of crystals, so the compressive strength of no burning building materials is greatly improved. After curing for 7 days and 28 days, the compressive strength of non burningsample (the mass ratio of phosphogypsum to cement is 4∶1) reaches 36.45 MPa and 38.12 MPa. The compressive strength of the sample soaked in water for 24 hours is still 21.03 MPa.

This is an article in the field of ceramics and composites.To explore the feasibility of using coal waste to replace cement for concrete preparation, the activated coal slag powder and coal gangue powder were used to replace cement at a ratio of 0%, 10%, 20%, 30%, and 40% to prepare concrete samples and prepare concrete samples. The slump, compressive strength, flexural strength and high-temperature performance were tested, and the results show that: as the substitution ratio increases, the slump, compressive strength and flexural strength all increase first and then decrease; The optimal substitution ratio is 20%～30%. The early strength growth rate of the activated coal slag powder sample is large; while the long-term strength growth rate of the activated coal gangue powder sample is large. When the water-cement ratio=0.45, the compressive strength of the sample increases first and then decreases with the increase of temperature, and reaches the maximum at 100 ℃; when the water-cement ratio=0.5, the compressive strength of the concrete sample increases with the temperature; the hydration cement structure in the interface area of the activated coal slag powder sample is the most, followed by the control group, and the activated coal gangue powder sample is the least. With the increase in temperature, the pores and cracks on the surface of the sample increased significantly and the degree of fracture of the damaged surface gradually increased.

This is an article in the field of ceramics and composites. Rheology and microstructure properties of iron-doped tailings 3D printing cementitious materials were studied in this paper. The results show that the particle size of tailings is small and can be used as aggregates for 3D printing materials. In the 3D printing process, it can smoothly pass through the pipeline for conveying the cementitious material. As the content of iron tailings continues to increase, the shear viscosity of 3D printing cementitious materials shows a trend that first decreases and then stabilizes in the region. However, the changing law of shear stress shows an increasing trend as the interval between layers increases. The compressive strength and flexural strength of 3D printing cementitious materials both show a decreasing trend. When the interval between layers is in between 20～30 min, the compressive strength and flexural strength decrease more slowly. As the interval between layers continues to increase, the interlayer bonding strength of 3D printing cementitious materials shows a decreasing trend. The 3D printing cementitious material with 30% iron tailings content is hydrated for 90 days after XRD diffraction test. The main material components of the cementitious material are quartz, ettringite, calcite, albite, perovskite, Ca2SiO4 and seven substances such as calcium silicate hydrate.

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Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources 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.)