An unconventional approach for the efficient recovery of iron, cobalt, copper and silicon from copper slag.

High-grade heavy metal elements in copper slag (CS) are worth recovering. Unfortunately, the high viscosity of leaching solution, low leaching efficiency, difficult filtration and low separation efficiency of valuable components exist in the traditional sulfuric acid leaching process. In this study, the above problems are solved by sulfuric acid pretreatment + curing + water leaching. Moreover, iron, cobalt and copper ions in solution are separated by stepwise precipitation. The final iron, cobalt, copper and silicon recoveries are 99.01 %, 98.45 %, 93.13 % and 99.52 %, respectively. Thermodynamic calculations show that H4SiO4 can be converted to insoluble SiO2 to improve filtration properties under curing conditions of sulfur dioxide partial pressures of 10-20∼0 atm, oxygen partial pressures of 10-20∼0 atm and 400-600k. Simulation studies of the phase equilibria of the components of the leach solution by Visual MINTEQ showed that the oxidation of Fe2+ to Fe3+ is necessary for the removal of Fe2+ from the solution by precipitation. This study provides a new idea for the efficient utilization of CS.

A novel approach for recovery of iron from copper slag using calcium salts.

Copper slag is not only a waste but it has many valuable and recoverable metals present in it such as iron. Therefore, this study focuses on the utilization of waste materials i.e., copper slag and tire char for iron recovery. Four calcium salts, i.e., CaCO3, Ca(OH)2, CaCl2, and CaSO4, with different dosages, reduction temperature, reduction time, and atmospheric conditions were investigated in order to find best reaction mechanism for iron recovery. Among these salts, the optimum conditions were determined: using CaCO3 under 0.384 of CaO/SiO2 molar ratio in a 60-min reduction period at 1473.15K temperature, that gives 91.14% iron recovery. Both FESEM-EDS data and chemical titration showed more than 70% of the highest iron grade in the recovered product. The analysis results indicate that main impurity in the whole procedure was carbon from coal char that reduces the iron grade. This research not only provides a novel way to recover iron from copper slag, but also provides a future direction to handle copper slag and tire char waste materials.

Speciation Characterization and Environmental Stability of Arsenic in Arsenic-Containing Copper Slag Tailing.

The increasing presence of arsenic-containing impurities within Cu ores can adversely affect the smelting process and aggravate the environmental impact of slag tailing. This study investigates the geochemical, mineralogical, and chemical speciation characteristics to better understand the association and environmental stability of metal(loid)s in copper slag tailing. The results indicate that the predominant chemical compositions of the selected slag tailing are Fe2O3 (54.8%) and SiO2 (28.1%). These tailings exhibit potential for multi-elemental contamination due to elevated concentrations of environmentally sensitive elements. Mineral phases identified within the slag tailings include silicate (fayalite), oxides (magnetite and hematite), and sulfides (galena, sphalerite, arsenopyrite, and chalcopyrite). The consistent presence of silicate, iron, arsenic, and oxygen in the elemental distribution suggests the existence of arsenic within silicate minerals in the form of Si-Fe-As-O phases. Additionally, arsenic shows association with sulfide minerals and oxides. The percentages of arsenite (As(III)) and arsenate (As(V)) within the selected slag tailings are 59.4% and 40.6%, respectively. While the slag tailings are deemed non-hazardous due to the minimal amounts of toxic elements in leachates, proper disposal measures should be taken due to the elevated carbonate-bound levels of As and Cu present in these tailings.

Influence of industrial waste and mineral admixtures on durability and sustainability of high-performance concrete.

The present research explores the strength, durability, microstructure, embodied energy, and global warming potential investigations made toward cleaner production of high-performance concrete (HPC) using a new composition. For this, various mixes were considered by replacing cement with metakaolin (MK) and silica fumes (SF) while simultaneously altering fine aggregates with industrial waste, copper slag (CS) in 0%, 25%, 50%, 75%, and 100% at 0.23 w/b ratio. The observations on fresh properties show a decrease in the slump due to pozzolans MK and SF but get compensated by the inclusion of copper slag simultaneously. HPC mixes with 50% replacement of CS revealed the best outcomes in compressive and splitting tensile strengths. Upon testing the concrete mixes against resistance to sulfate exposure, chloride penetration, and water absorption, the durability performance results best for modified mixes having 50% CS substitution levels. Scanning electron microscopy and energy dispersive spectroscopy support a 25% substitution of CS, showing a thickset microstructure with an ample amount of C-S-H gel with negligible cracks and capillary channels resulting in having best-strengthening properties. Overall, decrement in embodied energies and global warming potential has resulted with a reduction in the usage of cement and river sand in modified concrete mixes, ultimately making the production sustainable as well as environment friendly.

Reclamation of iron and copper from BCL slag in Botswana.

High-grade copper ores have been depleted over the years, making it a challenge in the mining industry. This investigation focused on a methodology to recover iron (Fe) and copper (Cu) from a copper/nickel slag obtained from the Bamangwato Concession Limited (BCL) mine in Botswana. In this modified flotation approach, the Response Surface Methodology (RSM) was used in conjunction with the Central Composite Design (CCD) and Analysis of Variance (ANOVA) to obtain the best optimal flotation conditions for the recovery of iron and copper. Using the RSM - CCD methodology, the optimal predicted responses were illustrated by a coefficient of determination R2 = 0. 9839 for recovery for Fe and 0.9655 for recovery for Cu. The recovery of copper increased with the increasing dosage of Na2S and collector dosage, while the increase of pH, had a decrease in recovery of copper due to the decline in the stability of the froth, which led to the resistance to form stable bubbles for efficient recovery of copper. Selective flotation of copper and iron was achieved by varying the Na2S dosage to achieve maximum recovery. Under these flotation conditions of PAX (800 g/t), pH (8), -75 µm, sulfurizing agent (Na2S, 1000 g/t), flotation time of 8 min, pH regulator of NaOH and H2SO4 and Methyl Isobutyl Carbinol (MIBC) from the experimental runs merited a grade upgrade of Cu in froth concentrate from 0.581 mass% to 0.884 mass%. An enrichment ratio of 2 was realised, with the recovery of Cu being 62%, whereas Fe in the froth concentrate increased from 69.8 mass% to 71.8 mass%. The main aim was to upgrade the grade and recovery of copper and iron to enhance the recovery for copper and iron in the next experimental stage of leaching.

An efficient eco-friendly adsorbent material based on waste copper slag-biomass ash geopolymer: dye sorption capacity and sustainable properties.

The primary intent of the research is to comprehensively assess the environmental benefits and cost dynamics associated with the adsorption process of CS-RHA (Copper Slag and Rice Husk Ash) to produce a novel geopolymer adsorbent material for application in wastewater treatment. The geopolymer forms a polyiron sialate network under alkali activation by dissolving fayalite, and aluminium silicate to ferro-ferri silicate hydrate gel. The mechanical strength, leaching characteristics, and microstructure of the geopolymer were determined using XRD and FTIR, and magnetic properties by VSM as well surface properties were derived from BET surface area and zeta potential. Recognizing the critical role of sodium iron silicate hydrate (NFS) in the sorption of methylene blue (MB) dyestuff, batch experiments were carried out using different adsorbents. The results indicated that the dye removal efficiency increased from 60% in control samples (FS) to 98% for the blend (FS1) under different pH values. The data was found to fit with the nonlinear form of Freundlich isotherm and follow pseudo-second-order kinetics. The active adsorption sites were deduced as -O-Fe-O-Si-O-Na and Si-OH groups. The addition of RHA increases the adsorption capacity of the geopolymer in a short time through chemical adsorption. The significant negative surface charge promotes MB adsorption via improved electrostatic attraction. The spent adsorbents were recovered through magnetic separation with a retrieval rate of 80-85% and active sites were rejuvenated by calcination. Consequently, waste copper slag emerges as a promising adsorbent with minimum potential ecological risk and high effective recycling capacity.

Investigation study data to develop sustainable concrete mix using waste materials as constituents.

Sustainable construction materials are those which contributes towards the carbon- negative process of manufacturing. Cement produced by raw materials from industrial wastes and non-fossil fuel sources is considered as green cement which has high potential in constructions due to high tensile strength and resistance to corrosion. Exploring replacement materials for conventional cement is an active area of research. This data investigation focused on development of novel concrete mix with various proportions of sustainable supplementary materials with cement, fine and coarse aggregate substances. Alccofine, Metakaolin, GGBFS, Foundry sand, Copper slag, Recycled aggregate and Sintered fly ash aggregate are suitable supplementary materials of the concrete mix. Data projected replacement of cement by 15 % Alccofine, 10% Metakaolin and 30% GGBFS substitution and Fine aggregates (50% Copper slag, 30% Foundry sand) and replacement of Coarse aggregate (20% Recycled and 30% Sintered Fly Ash aggregate) will produce sustainable concrete mixture. Compressive and split tensile strength examined at 7th, 14th and 28th day and compared with conventional concrete. This data shows that the concrete mixture CFACA 1234567 was outperformed among the five mixture studied.

An efficient approach to utilize copper smelting slag: Separating nonferrous metals and reducing iron oxide at high temperature.

Over 50 million tons of copper slag are produced worldwide annually. Stacking is currently the primary method used to treat copper slag, resulting in resource wastage and environmental issues. Using slag as a raw material in the steel industry is areasonablesolution. However, the presence of nonferrous metals degrades steel performance and corrodes smelting equipment, and the remaining slag poses environmental and sustainable challenges. Thus, this study focused on removal of nonferrous metals from copper slag and subsequent reduction of iron oxide. The experimental results showed that increasing the percentage of the chlorinating agent (calcium chloride), temperature, and duration, the removal percentage of copper initially increased linearly, then plateaued. The acidity coefficient had a marginal effect on copper removal percentage. The optimum chlorination roasting conditions were 13 % calcium chloride, 1373 K, and 0.5 h, resulting in removal percentages of 90.3 %, 81.9 %, and 82.7 % for copper, zinc, and lead, respectively. The appropriate oxygen partial pressure for chlorination roasting was 10-5-0.7 atm. The reduction percentage of iron oxide was approximately 82 % under roasting conditions of 1.5 h at 1373 K. Based on these results, a novel scheme for copper slag utilization is proposed that involves chlorination roasting for nonferrous metal removal, reduction roasting for iron oxide reduction, and melting to obtain molten iron and separate molten slag. The iron and slag are used for steel manufacturing and rock wool preparation, respectively. This scheme provides apromisingway to efficiently use copper slag, which will reduce primary resource consumption and pollution.

Co-recovery of Mn and Fe from pyrolusite and copper slag with hydrometallurgy process: Kinetics and leaching mechanisms.

With the shortage of high-quality raw materials and increasingly strict environmental regulations, the recovery of metals from copper slag and pyrolusite has become a research hotspot. A novel method for simultaneously extracting Mn and Fe from pyrolusite and copper slag has been proposed. Under the optimal conditions (Copper slag / Pyrolusite = 2, H2SO4 = 2 M, liquid-solid ratio = 10, T = 90 ℃, holding time = 60 min), the leaching efficiencies of Mn and Fe can reach 98.28% and 99.04%, respectively. In addition, the treated residue containing 60.04 wt% SiO2 can be used as a raw building material. Through chemical kinetics and mineralogical transformation analyses, Fe2SiO4 in copper slag decomposes to release Fe2+, which can reduce and leach Mn from pyrolusite. The unreacted shrinkage nuclear reaction model under the control of the surface chemical reaction is the most suitable model to describe the process, and when the apparent activation energy is 35.50 kJ/mol, the apparent rate equation is: [Formula: see text].

Exploring the Potential of Alternative Materials in Concrete Mixtures: Effect of Copper Slag on Mechanical Properties and Carbonation Resistance.

In this study, the effect on the flowability, compressive strength, absorption, sorptivity, and carbonation resistance of concrete with different copper slag (CS) replacement ratios was investigated. For this research, four concrete mixes with different percentages of CS were made (0%, 10%, 20%, and 30% of CS as replacement of cement by volume). In addition, the microstructure was analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), and thermogravimetric analysis (TG-DTG). The results shows that the incorporation of CS reduces the workability and compressive strength of the mixtures, being more significant in concrete with 30% CS. The carbonation depth of concrete with CS increases monotonically with increasing CS. In addition, the compressive strength of the carbonated (20% and 30% CS) concretes show a loss of compressive strength at 90 days of exposure when compared to their water-cured counterparts. The use of low percentages of CS does not generate a decrease in workability and its mechanical effect is not significant at prolonged ages, so the use of this waste as SCM in percentages close to 10% is a viable alternative to the sustainability of concrete and the management of this residue.

Mineralogical Characterization of Historic Copper Slag to Guide the Recovery of Valuable Metals: A Namibian Case Study.

The depletion of the ore reserves in the world necessitates the search for secondary sources such as waste products (tailings and slag). The treatment and cleaning up of such secondary sources also has a positive impact on the environment. A smelter in Namibia we examined had historic slag which accumulated over decades of its operating life, thus posing the challenge of how best to collect representative samples to evaluate and propose viable methods of recovering contained metals. In this study, analytical and mineralogical characterization of the slag was performed using X-ray fluorescence (XRF) analysis, atomic absorption spectrometer (AAS), ICP-OES, scanning electron microscopy energy dispersive spectroscopy (SEM-EDS) analysis, and optical microscopy analysis. The chemical analyses showed that the metal values contained in the slag were mainly copper, lead, and zinc whose average contents were approximately 0.35% Cu, 3% Pb, and 5.5% Zn. About 10.5% Fe was also contained in the slag. Germanium was detected by scanning electron microscopy, but was however below detection limits of the chemical analysis equipment used. Based on the results, approximate conditions under which the different slag phases were formed were estimated and the recovery routes for the various metals were proposed. Analysis by both optical and scanning electron microscopy revealed that Zn and Fe occurred mainly in association with O as oxides, while Cu and Pb were mainly associated with S as sulphides. The slag consisted of three different phases, namely the silicate phase (slag), metallic phase and the sulphide phases. The phases in the slag were mainly silicate phases as well as metallic and sulphide phases. It was observed that the metallic and sulphide phases were dominant in the finer size fractions (-75 µm) whereas the sulphide phase was also present in the coarser size fractions (+300 µm). An important finding from the microscopy examination was that the sulphide phases were interstitial and could be liberated from the slag. This finding meant that liberation and subsequent concentration of the sulphide phases was feasible using conventional processing techniques.

The Influence of the Thermal Treatment of Copper Slag on the Microstructure and Performance of Phosphate Cements.

In general, phosphate cements have a very rapid setting reaction at room temperature. The same holds for copper slag-based phosphate cements. This means that using them as a binder, for instance as mortar, is always possible on a small scale, but very difficult on a large scale. In this paper, the heat treatment of the copper slag was shown to be an effective way to increase the setting time and keep the mix workable for an adequate period. The main objective of this research was to examine the changes in the phase composition of quenched copper slag after exposure to 500 °C and to evaluate the impact of these changes on the reactivity of the material in an acidic environment, as well as on the mechanical properties, microstructure, and structure of the produced phosphate cement materials. Various experimental methods were utilized to characterize the raw materials and the obtained phosphate cementitious materials, including isothermal microcalorimetry (TAM Air), thermogravimetric analysis (TGA), infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), as well as the determination of the chemical composition using X-ray fluorescence (XRF) and the particle size distribution. Furthermore, compressive strength tests were conducted to gauge the mechanical resistance of the materials. The main findings of this work revealed that subjecting the copper slag to a thermal treatment of 500 °C induced a partial transformation in its structure. The high temperature caused the oxidation of some of the divalent iron oxide in the slag, leading to the formation of hematite. This treatment increased the setting time and reduced the reactivity of the copper slag with phosphoric acid, ultimately enabling the production of a dense phosphate-based cementitious material with outstanding mechanical properties. The compressive strength of the newly developed cement was recorded to be greater than 78.9 MPa after 7 days, and this strength continued to increase, reaching 82.5 MPa after 28 days.

Contaminant release from massive copper metallurgical slags: Insights from long-term monolithic leaching tests.

Compared to compliance leaching tests performed on granular materials, leaching experiments on monolithic slags are more suitable for predicting the contaminant release when large boulders or poured slag layers are submerged in water, a specific environmental scenario typical for many smelting sites. We conducted EN 15863 dynamic monolithic leaching tests on massive copper slags over a prolonged period of 168 d. The patterns of the major contaminant (Cu, Co) fluxes indicated an initial diffusion process followed by the dissolution of primary sulfides with the maximum cumulative releases attaining 75.6 mg/m2 Cu and 4.20 mg/m2 Co. A multi-method mineralogical investigation showed that lepidocrocite (γ-FeOOH) and goethite (α-FeOOH) started to form on the slag surface already after 9 d of leaching and partly immobilized Cu (but not Co). Vanadium and other trace elements (Zn, Pb, Cd) were leached to a much lower extent, initially controlled by diffusion followed by depletion and/or sorption to Fe oxyhydroxides. The results of the long-term leaching of the monolithic slag provide new information about the key processes affecting the release of metal (loid) contaminants under specific submerged conditions and have implications for the environmental management of slag disposal sites and/or potential reuse of slags in civil engineering.

Potential of major by-products from non-ferrous metal industries for CO2 emission reduction by mineral carbonation: a review.

By-products from the non-ferrous industry are an environmental problem; however, their economic value is high if utilized elsewhere. For example, by-products that contain alkaline compounds can potentially sequestrate CO2 through the mineral carbonation process. This review discusses the potential of these by-products for CO2 reduction through mineral carbonation. The main by-products that are discussed are red mud from the alumina/aluminum industry and metallurgical slag from the copper, zinc, lead, and ferronickel industries. This review summarizes the CO2 equivalent emissions generated by non-ferrous industries and various data about by-products from non-ferrous industries, such as their production quantities, mineralogy, and chemical composition. In terms of production quantities, by-products of non-ferrous industries are often more abundant than the main products (metals). In terms of mineralogy, by-products from the non-ferrous industry are silicate minerals. Nevertheless, non-ferrous industrial by-products have a relatively high content of alkaline compounds, which makes them potential feedstock for mineral carbonation. Theoretically, considering their maximum sequestration capacities (based on their oxide compositions and estimated masses), these by-products could be used in mineral carbonation to reduce CO2 emissions. In addition, this review attempts to identify the difficulties encountered during the use of by-products from non-ferrous industries for mineral carbonation. This review estimated that the total CO2 emissions from the non-ferrous industries could be reduced by up to 9-25%. This study will serve as an important reference, guiding future studies related to the mineral carbonation of by-products from non-ferrous industries.

Simultaneously Cationic and Anionic Dyes Elimination via Magnetic Hydrochar Prepared from Copper Slag and Pinewood Sawdust.

In practical wastewater, cationic and anionic dyes usually coexist, while synergistic removal of these pollutants is difficult due to their relatively opposite properties. In this work, copper slag (CS) modified hydrochar (CSHC) was designed as functional material by the one-pot method. Based on characterizations, the Fe species in CS can be converted to zero-valent iron and loaded onto a hydrochar substrate. The CSHC exhibited efficient removal rates for both cationic dyes (methylene blue, MB) and anionic dyes (methyl orange, MO), with a maximum capacity of 278.21 and 357.02 mg·g-1, respectively, which was significantly higher than that of unmodified ones. The surface interactions of MB and MO between CSHC were mimicked by the Langmuir model and the pseudo-second-order model. In addition, the magnetic properties of CSHC were also observed, and the good magnetic properties enabled the adsorbent to be quickly separated from the solution with the help of magnets. The adsorption mechanisms include pore filling, complexation, precipitation, and electrostatic attraction. Moreover, the recycling experiments demonstrated the potential regenerative performance of CSHC. All these results shed light on the co-removal of cationic and anionic contaminates via these industrial by-products derived from environmental remediation materials.

Ultrasound effects on restricted silica gelation during silica extraction from Pyro-Metallurgical copper slag under acidifying conditions.

Pyro-metallurgical copper slag (CS) waste was used as the source material for ultrasound (US) silica extraction under acidification processes with 26 kHz with HCl, HNO3, and H2SO4 at different concentrations at 100, 300, and 600 W. During acidifying extraction processes, US irradiation inhibited silica gel formation under acidic conditions, especially at lower acid concentrations of less than 6 M, whereas a lack of US irradiation led to enhanced gelation. When US stopped, gelation occurred to a considerable degree, suggesting that the gel particle size distribution was aggregated in the 3-400 µm size range. However, with US, the size was mainly in the 1-10 µm range. Results of elemental analysis indicated that US treatment decreased the co-precipitation of other metal ions such as Fe, Cu, and Al sourced from CS for lower acidic medium, whereas the higher concentration medium accelerated silica gelation and the co-precipitation of other metals. With acids of HCl and HNO3, and H2SO4, the gelations were less likely to occur at 6 M and 3 M during US irradiation, but acidic extraction without US was efficient for silica gelation and co-precipitation of other metals in the purified silica. The silica extraction yield with H2SO4 concentration of 3 M was 80% with 0.04% of Fe, whereas the silica product from HCl 6 M had a 90% extraction yield with only 0.08% of Fe impurity. In contrast, even though the non-US system of HCl 6 M had a higher yield at 96%, the final product had 0.5% Fe impurity, which was much higher than the US system. Consequently, the US extraction process was quite noticeable for silica recovery from CS waste.

Strength, durability, and microstructure of self-compacting geopolymer concrete produced with copper slag aggregates.

Lack of vibrations on fresh concrete negatively influences the compaction and thus the quality of concrete. This is particularly concerning with geopolymer concrete (GPC) containing sodium silicate (Na2SiO3), which is viscous in nature. In this study, self-compacting geopolymer concrete (SCGC) containing fly ash (FA) and ultrafine slag (UFS) with copper slag aggregates (CSA) was proposed and investigated. CSA were used as a substitute to sand (by weight) in SCGC at different percentages up to 60%. In the fresh state, slump, T500 slump flow, V-funnel, L-box, U-box, and sieve aggregation ratio tests were performed to investigate flowability, passing ability, and viscosity. At the hardened state, the compressive strength, water absorption, chloride ion resistance and sorptivity tests were examined. The flowability of SCGC improved when CSA were added, and the highest slump of 735 mm was achieved for the mix with 60% CSA. Substitution of up to 20% of CSA enhanced the properties of SCGC at all ages. Mix having 20% CSA (20CSA-SCGC) was superior to other mixes, exhibiting the highest compressive strength (47 MPa) at 365 days while possessing the lowest water absorption, sorptivity, and the highest chloride ion resistance. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) analyses also confirmed the improved microstructure of Mix 20CSA-SCGC. Meanwhile, X-ray diffraction (XRD) analysis confirmed the presence of quartz and calcium silicate hydrate (CSH) products, which were the main contributors to properties enhancement.

A Study on Chloride Corrosion Resistance of Reactive Powder Concrete (RPC) with Copper Slag Replacing Quartz Sand under Freeze-Thaw Conditions.

In order to study the influence of freeze-thaw cycles on chloride ion corrosion resistance of RPC with copper slag (CS) instead of quartz sand (QS), the 28d uniaxial compressive strength (UCS) of CSRPC with a different CS substitution rate was investigated by unconfined compression tests. The electric flux test method was used to study the chloride ion diffusion resistance of CSRPC after freeze-thaw cycles, and the pore size distribution was obtained through the nuclear magnetic resonance (NMR) method. Then, a mathematical relationship between the chloride ion diffusion coefficient and the pore fractal characteristic parameter T was established to study the effect of freeze-thaw cycles on chloride ion diffusion. Finally, SEM/EDS, XRD, and DTG methods were combined to study the influence of the distribution of Friedel's salts generated after freeze-thaw cycles on chloride ion diffusion in CSRPC. The results indicate that CS has a micro aggregate effect and pozzolanic activity, which can effectively improve the chloride ion diffusion resistance of CSRPC after freeze-thaw cycles. In addition, the electric flux of CSRPC decreases with the increase in freeze-thaw cycles, and the chloride diffusion coefficient is closely related to the pore fractal dimension.

Selenite elimination via zero-valent iron modified biochar synthesized from tobacco straw and copper slag: Mechanisms and agro-industrial practicality.

Cost-effectively improving the performance of biochar is essential for its large-scale practical application. In this work, the agro-industrial by-products copper slag and tobacco straw were employed for the preparation of modified biochar (CSBC). The obtained CSBC exhibited satisfactory capacity on Se(IV) immobilization of 190.53 mg/g, with surface interactions determined by the monolayer and mainly chemisorption. The removal mechanisms included chemical reduction, electrostatic attraction, co-precipitation, and formation of complexations. Interestingly, the existence of Cu2Se structure after adsorption indicated the involvement of Cu species within Se(IV) elimination. Moreover, the industrial agricultural practicality of CSBC was evaluated by regeneration tests, economic assessment, and pot experiments. The results demonstrate that iron species-modified biochar prepared from two agro-industrial by-products is a promising and feasible candidate for selenite removal from wastewater.

A Review of the Influence of Copper Slag on the Properties of Cement-Based Materials.

Global copper slag (CS) emissions reached 57.2 million tons in 2021. Despite the increasing reuse of CS, the treatment of CS is still dominated by landfill so far, which not only occupies land resources but also causes damage to the environment. The application of CS to cement-based materials (CBMs) is one of the main approaches to its comprehensive utilization and has important economic and social implications. This article reviews the physicochemical properties, activity excitation, and heavy metal leaching properties of CS and summarizes the effect of CS on the working properties, mechanical properties, and durability of CBMs. At the end of the article, the existing problems in the research are analyzed, and the development trend is proposed, which provides technical guidance and reference for further research and application of CS in CBMs in the future.