Pub Date : 2026-02-01DOI: 10.1016/j.mineng.2026.110122
Yuhua Zhu , Cheng Liu , Hongyang Wang , Wei Xu , Siyuan Yang
Flotation separation of apatite from dolomite is still a challenge due to their similar surface characteristics. To address this issue, polyamino polyether methylene phosphonic acid (PAPEMP) was employed to separate apatite and dolomite. The single-mineral flotation results showed that PAPEMP selectively depressed the floatability of dolomite using the sodium oleate (NaOl) collector. The artificial mixed mineral and real flotation tests confirmed that separation between apatite and dolomite could be realized in the reagent scheme of PAPEMP/NaOl. The adsorption tests indicated that the adsorption of PAPEMP on the dolomite surface was much greater than that on the apatite surface. The zeta potential and Fourier Transform Infrared Spectroscopy (FTIR) experiments verified that the interaction between dolomite and PAPEMP was stronger than that between apatite and PAPEMP, then selectively hindered the interaction of NaOl with the dolomite surface. The XPS results indicated that phosphate groups in the PAPEMP molecule interact with calcium/magnesium ions on the dolomite surface, while no effective chemical interaction occurred between PAPEMP and the apatite surface. MS calculation results further confirmed that the interaction between PAPEMP and the dolomite surface was stronger than that between PAPEMP and the apatite surface. Therefore, PAPEMP could be used as an appropriate depressant to separate apatite and dolomite.
{"title":"Evaluation of polyamino polyether methylene phosphonic acid as an eco-friendly depressant in the separation of apatite and dolomite","authors":"Yuhua Zhu , Cheng Liu , Hongyang Wang , Wei Xu , Siyuan Yang","doi":"10.1016/j.mineng.2026.110122","DOIUrl":"10.1016/j.mineng.2026.110122","url":null,"abstract":"<div><div>Flotation separation of apatite from dolomite is still a challenge due to their similar surface characteristics. To address this issue, polyamino polyether methylene phosphonic acid (PAPEMP) was employed to separate apatite and dolomite. The single-mineral flotation results showed that PAPEMP selectively depressed the floatability of dolomite using the sodium oleate (NaOl) collector. The artificial mixed mineral and real flotation tests confirmed that separation between apatite and dolomite could be realized in the reagent scheme of PAPEMP/NaOl. The adsorption tests indicated that the adsorption of PAPEMP on the dolomite surface was much greater than that on the apatite surface. The zeta potential and Fourier Transform Infrared Spectroscopy (FTIR) experiments verified that the interaction between dolomite and PAPEMP was stronger than that between apatite and PAPEMP, then selectively hindered the interaction of NaOl with the dolomite surface. The XPS results indicated that phosphate groups in the PAPEMP molecule interact with calcium/magnesium ions on the dolomite surface, while no effective chemical interaction occurred between PAPEMP and the apatite surface. MS calculation results further confirmed that the interaction between PAPEMP and the dolomite surface was stronger than that between PAPEMP and the apatite surface. Therefore, PAPEMP could be used as an appropriate depressant to separate apatite and dolomite.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":"239 ","pages":"Article 110122"},"PeriodicalIF":5.0,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146110838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-31DOI: 10.1016/j.mineng.2026.110127
Yuanxing Yue , Yongsheng Sun , Peng Gao , Yuexin Han , Zhidong Tang
The comprehensive utilization of Bayan Obo tailings is hindered by the coexistence of iron and rare earth element (REE) minerals, which require distinct beneficiation conditions. To enhance process compatibility and overall resource recovery, a synergistic separation strategy based on early-stage physical decoupling of iron- and REE-bearing streams is proposed. Magnetic pre-enrichment was first applied to partition the tailings into an iron-rich concentrate and a REE-enriched tailings stream. The iron-rich fraction underwent hydrogen-based mineral phase transformation (HMPT), followed by grinding and magnetic separation, producing a high-grade iron concentrate with 66.16% TFe at a recovery of 76.44%. Concurrently, the REE-enriched tailings were directly processed by flotation without thermal treatment, yielding a rare earth concentrate with 50.38% REO at a recovery of 58.62%. This decoupled flowsheet allows iron and REEs to be processed under conditions tailored to their respective separation requirements, thereby reducing cross-process interactions. Mechanism studies using XRD confirmed hematite-to-magnetite transformation; XPS revealed Fe3+/Fe2+ reduction and strong chemical interaction between BHA and Ce ions; SEM-EDS illustrated microcrack-enhanced gas–solid reactions. Overall, the proposed H2-based integrated route provides a practical, low-carbon strategy for coordinated iron and REE recovery from complex tailings, improving both process efficiency and resource utilization.
{"title":"A synergistic H2-Based process for co-recovery of iron and rare earth elements from complex Tailings: Toward a Zero-Waste strategy","authors":"Yuanxing Yue , Yongsheng Sun , Peng Gao , Yuexin Han , Zhidong Tang","doi":"10.1016/j.mineng.2026.110127","DOIUrl":"10.1016/j.mineng.2026.110127","url":null,"abstract":"<div><div>The comprehensive utilization of Bayan Obo tailings is hindered by the coexistence of iron and rare earth element (REE) minerals, which require distinct beneficiation conditions. To enhance process compatibility and overall resource recovery, a synergistic separation strategy based on early-stage physical decoupling of iron- and REE-bearing streams is proposed. Magnetic pre-enrichment was first applied to partition the tailings into an iron-rich concentrate and a REE-enriched tailings stream. The iron-rich fraction underwent hydrogen-based mineral phase transformation (HMPT), followed by grinding and magnetic separation, producing a high-grade iron concentrate with 66.16% TFe at a recovery of 76.44%. Concurrently, the REE-enriched tailings were directly processed by flotation without thermal treatment, yielding a rare earth concentrate with 50.38% REO at a recovery of 58.62%. This decoupled flowsheet allows iron and REEs to be processed under conditions tailored to their respective separation requirements, thereby reducing cross-process interactions. Mechanism studies using XRD confirmed hematite-to-magnetite transformation; XPS revealed Fe<sup>3+</sup>/Fe<sup>2+</sup> reduction and strong chemical interaction between BHA and Ce ions; SEM-EDS illustrated microcrack-enhanced gas–solid reactions. Overall, the proposed H<sub>2</sub>-based integrated route provides a practical, low-carbon strategy for coordinated iron and REE recovery from complex tailings, improving both process efficiency and resource utilization.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":"239 ","pages":"Article 110127"},"PeriodicalIF":5.0,"publicationDate":"2026-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146095829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-30DOI: 10.1016/j.mineng.2026.110110
Yunzhen Hu , Kangjing Wu , Shuai Wang , Zhanfang Cao , Xin Ma , Hong Zhong
The flotation separation of chalcopyrite and galena remains challenging due to their similar surface properties. Here, we demonstrate that H2O2 pretreatment passivates Cu sites (forming Cu–O) while activating Pb sites (forming Pb–O) on mineral surfaces, which transforms sodium 2-(dithiocarboxylato)ethyl acetate (DTCA) from non-selective into a galena-selective depressant. Micro-flotation experiments indicate that with H2O2 oxidation duration of 30 min, pH of 10, and DTCA dosage of 100 mg/g, galena recovery can be reduced to below 5% while maintaining chalcopyrite recovery above 90%. Following oxidation, the adsorption amount of chalcopyrite decreased from 96.54 to 7 mg/g, while that of galena increased from 101.32 to 102.45 mg/g. Multiscale characterizations (FTIR, XPS, ToF-SIMS) indicate that DTCA adsorbs onto the surfaces of chalcopyrite and galena, respectively, via chelation between S–Cu–S and S–Pb–S bonds. Density functional theory (DFT) calculations confirm that oxidation enhanced the adsorption strength of DTCA on the surface of galena, with the adsorption energy shifting from −2.571 to −2.645 eV. Conversely, adsorption strength decreased significantly after oxidation of chalcopyrite, with the adsorption energy shifting from −2.470 to −1.588 eV. Closed-circuit tests on industrial concentrates yielded copper recovery and grade reached 93.13% and 27.43%, respectively, while lead achieved 96.33% recovery and 43.21% grade, with a separation index (SI) of 2.55, surpassing that achieved by the toxic potassium dichromate(K2Cr2O7) method. This study proposes a Cr (VI)-free flotation strategy for efficient Cu–Pb separation, offering a promising alternative to conventional environmentally hazardous methods.
{"title":"H2O2-mediated surface chemistry converts a non-selective depressant to galena-selective for efficient Cu–Pb flotation separation","authors":"Yunzhen Hu , Kangjing Wu , Shuai Wang , Zhanfang Cao , Xin Ma , Hong Zhong","doi":"10.1016/j.mineng.2026.110110","DOIUrl":"10.1016/j.mineng.2026.110110","url":null,"abstract":"<div><div>The flotation separation of chalcopyrite and galena remains challenging due to their similar surface properties. Here, we demonstrate that H<sub>2</sub>O<sub>2</sub> pretreatment passivates Cu sites (forming Cu–O) while activating Pb sites (forming Pb–O) on mineral surfaces, which transforms sodium 2-(dithiocarboxylato)ethyl acetate (DTCA) from non-selective into a galena-selective depressant. Micro-flotation experiments indicate that with H<sub>2</sub>O<sub>2</sub> oxidation duration of 30 min, pH of 10, and DTCA dosage of 100 mg/g, galena recovery can be reduced to below 5% while maintaining chalcopyrite recovery above 90%. Following oxidation, the adsorption amount of chalcopyrite decreased from 96.54 to 7 mg/g, while that of galena increased from 101.32 to 102.45 mg/g. Multiscale characterizations (FTIR, XPS, ToF-SIMS) indicate that DTCA adsorbs onto the surfaces of chalcopyrite and galena, respectively, via chelation between S–Cu–S and S–Pb–S bonds. Density functional theory (DFT) calculations confirm that oxidation enhanced the adsorption strength of DTCA on the surface of galena, with the adsorption energy shifting from −2.571 to −2.645 eV. Conversely, adsorption strength decreased significantly after oxidation of chalcopyrite, with the adsorption energy shifting from −2.470 to −1.588 eV. Closed-circuit tests on industrial concentrates yielded copper recovery and grade reached 93.13% and 27.43%, respectively, while lead achieved 96.33% recovery and 43.21% grade, with a separation index (SI) of 2.55, surpassing that achieved by the toxic potassium dichromate(K<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>) method. This study proposes a Cr (VI)-free flotation strategy for efficient Cu–Pb separation, offering a promising alternative to conventional environmentally hazardous methods.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":"239 ","pages":"Article 110110"},"PeriodicalIF":5.0,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146079658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-30DOI: 10.1016/j.mineng.2026.110114
Yuntao Zhu , Zhong Luo , Haobin Wang , Qirun Zhou , Zhen Zhang
Particle behavior directly influences the classification performance of vertical roller mills (VRMs), but limited understanding hinders structural optimization. This study employs the CFD–DEM method to investigate the flow characteristics and segregation behavior of particles with different densities under air induction, and innovatively proposes “VRM bend pipe model” hypothesis to explain particle retention and roping phenomena. Results show that dual-inlet confluence generates a dual-spiral flow field, creating strong and weak airflow zones and subsequent cyclic, periodically segregated particle flows. High-density particles exhibit time lag and larger turning radius. The segregation index along the stationary blades shows a “digit-3” axial distribution, with a DI = 0 fixed point that tends to rise. Local analysis reveals that deflector in the air ring promotes outer-side particle accumulation, forming stagnant “dead zone”, while high-density particles form an annular distribution at the millstone center, and a transport mechanism exists wherein particles migrate downward along the millstone wall against the airflow. In the stationary blade zone, low-density particles form continuous streams, whereas high-density ones exhibit intermittent flow with more severe local segregation. In the upper shell zone, particles undergo coupled segregation governed by both density differences and flow-field induction. This study deepens the understanding of gas–solid flow and particle separation mechanisms in VRMs, providing theoretical support for design optimization.
{"title":"Air-induced segregation of micron-scale particles in a vertical roller mill","authors":"Yuntao Zhu , Zhong Luo , Haobin Wang , Qirun Zhou , Zhen Zhang","doi":"10.1016/j.mineng.2026.110114","DOIUrl":"10.1016/j.mineng.2026.110114","url":null,"abstract":"<div><div>Particle behavior directly influences the classification performance of vertical roller mills (VRMs), but limited understanding hinders structural optimization. This study employs the CFD–DEM method to investigate the flow characteristics and segregation behavior of particles with different densities under air induction, and innovatively proposes “VRM bend pipe model” hypothesis to explain particle retention and roping phenomena. Results show that dual-inlet confluence generates a dual-spiral flow field, creating strong and weak airflow zones and subsequent cyclic, periodically segregated particle flows. High-density particles exhibit time lag and larger turning radius. The segregation index along the stationary blades shows a “digit-3” axial distribution, with a <em>DI</em> = 0 fixed point that tends to rise. Local analysis reveals that deflector in the air ring promotes outer-side particle accumulation, forming stagnant “dead zone”, while high-density particles form an annular distribution at the millstone center, and a transport mechanism exists wherein particles migrate downward along the millstone wall against the airflow. In the stationary blade zone, low-density particles form continuous streams, whereas high-density ones exhibit intermittent flow with more severe local segregation. In the upper shell zone, particles undergo coupled segregation governed by both density differences and flow-field induction. This study deepens the understanding of gas–solid flow and particle separation mechanisms in VRMs, providing theoretical support for design optimization.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":"239 ","pages":"Article 110114"},"PeriodicalIF":5.0,"publicationDate":"2026-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146072485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1016/j.mineng.2026.110120
Liuyang Dong , Yanru Cui , Shengzong Lan , Tianfu Zhang , Yuqiang Mao , Peilun Shen , Dianwen Liu
Apatite, a vital calcium-bearing mineral, presents significant challenges in separation due to its complex mineralogy and frequent intergrowth with gangue minerals such as calcite and dolomite. Given that the physical and chemical properties of these associated calcium-bearing mineral impurities are highly similar to those of apatite, the flotation behaviors of the two also exhibit significant convergence. Therefore, traditional separation techniques are difficult to achieve efficient separation of apatite from the calcium-bearing impurities. The difficulties are further compounded by several factors: the analogous surface characteristics between apatite and common gangue minerals lead to poor selectivity of conventional reagents, adversely affecting concentrate quality; the finely disseminated nature of the minerals often results in either inadequate liberation or overgrinding during milling, increasing separation complexity and reducing efficiency; and the mineral’s high chemical reactivity in aqueous environments—where dissolution, hydrolysis, and varying surface composition occur—along with interference from dissolved ions, complicates reagent adsorption and process control. This review paper examines the resource characteristics, physicochemical properties, beneficiation methods, and flotation reagents of phosphate ores, supported by representative case studies. With a focus on elucidating the mechanisms of selective depressants in apatite flotation. This work aims to provide a scientific basis for the efficient and sustainable utilization of phosphate resources, offering insights for future development and enhanced flotation performance to achieve cleaner and more effective phosphate beneficiation.
{"title":"Advances in phosphate ores flotation: Cleaning reagents, green practices and perspectives","authors":"Liuyang Dong , Yanru Cui , Shengzong Lan , Tianfu Zhang , Yuqiang Mao , Peilun Shen , Dianwen Liu","doi":"10.1016/j.mineng.2026.110120","DOIUrl":"10.1016/j.mineng.2026.110120","url":null,"abstract":"<div><div>Apatite, a vital calcium-bearing mineral, presents significant challenges in separation due to its complex mineralogy and frequent intergrowth with gangue minerals such as calcite and dolomite. Given that the physical and chemical properties of these associated calcium-bearing mineral impurities are highly similar to those of apatite, the flotation behaviors of the two also exhibit significant convergence. Therefore, traditional separation techniques are difficult to achieve efficient separation of apatite from the calcium-bearing impurities. The difficulties are further compounded by several factors: the analogous surface characteristics between apatite and common gangue minerals lead to poor selectivity of conventional reagents, adversely affecting concentrate quality; the finely disseminated nature of the minerals often results in either inadequate liberation or overgrinding during milling, increasing separation complexity and reducing efficiency; and the mineral’s high chemical reactivity in aqueous environments—where dissolution, hydrolysis, and varying surface composition occur—along with interference from dissolved ions, complicates reagent adsorption and process control. This review paper examines the resource characteristics, physicochemical properties, beneficiation methods, and flotation reagents of phosphate ores, supported by representative case studies. With a focus on elucidating the mechanisms of selective depressants in apatite flotation. This work aims to provide a scientific basis for the efficient and sustainable utilization of phosphate resources, offering insights for future development and enhanced flotation performance to achieve cleaner and more effective phosphate beneficiation.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":"239 ","pages":"Article 110120"},"PeriodicalIF":5.0,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146072445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1016/j.mineng.2026.110115
Heewon Kang, Jeongwoo Kim, Jaehoon Lee, Dagyeong Lee, Daniel Ko, Hyunjung Kim
This study investigates the early-stage leaching behavior and temperature-dependent kinetics of saprolitic laterite (SL) and limonitic laterite (LL) ores under atmospheric acid leaching conditions at various temperatures to capture early-stage dissolution of nickel, magnesium, and iron. Both ores exhibited temperature-dependent increases in metal extraction, with highest extractions observed at 45 °C for saprolitic laterite ore and 65 °C for limonitic laterite ore. Structural analysis of leach residues revealed that the highest extractions corresponded to progressive collapse of key minerals—lizardite in saprolitic laterite ore and goethite and clinochlore in limonitic laterite ore. Kinetic analysis using a shrinking core model showed that solid product layer diffusion was the dominant rate-limiting step for all metals in both ores. Activation energies exceeding 56 kJ/mol for all metals suggested diffusion resistances, likely due to the formation of silica-rich product layers. This study clarifies the mineral leach mechanisms governing early-stage leaching in saprolitic laterite and limonitic laterite ores and provide a basis for optimizing selective nickel leaching.
{"title":"Early-stage temperature-dependent leaching kinetics and mechanisms of saprolitic and limonitic nickel laterite ores under atmospheric conditions","authors":"Heewon Kang, Jeongwoo Kim, Jaehoon Lee, Dagyeong Lee, Daniel Ko, Hyunjung Kim","doi":"10.1016/j.mineng.2026.110115","DOIUrl":"10.1016/j.mineng.2026.110115","url":null,"abstract":"<div><div>This study investigates the early-stage leaching behavior and temperature-dependent kinetics of saprolitic laterite (SL) and limonitic laterite (LL) ores under atmospheric acid leaching conditions at various temperatures to capture early-stage dissolution of nickel, magnesium, and iron. Both ores exhibited temperature-dependent increases in metal extraction, with highest extractions observed at 45 °C for saprolitic laterite ore and 65 °C for limonitic laterite ore. Structural analysis of leach residues revealed that the highest extractions corresponded to progressive collapse of key minerals—lizardite in saprolitic laterite ore and goethite and clinochlore in limonitic laterite ore. Kinetic analysis using a shrinking core model showed that solid product layer diffusion was the dominant rate-limiting step for all metals in both ores. Activation energies exceeding 56 kJ/mol for all metals suggested diffusion resistances, likely due to the formation of silica-rich product layers. This study clarifies the mineral leach mechanisms governing early-stage leaching in saprolitic laterite and limonitic laterite ores and provide a basis for optimizing selective nickel leaching.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":"239 ","pages":"Article 110115"},"PeriodicalIF":5.0,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146072443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sulfidized nano zero-valent iron (S-nZVI) is an exceptional wastewater treatment material, but its excessively high preparation costs severely restrict its industrial applications. In this study, a carbothermal reduction method was developed to prepare quartz-supported S-nZVI (SiO2@S-nZVI) from limonite ore and pyrite. The preparation conditions, characteristics, preparation mechanism of SiO2@S-nZVI, and its performance in removing organic contaminants were investigated. Batch experiments revealed that SiO2@S-nZVI prepared under the conditions of an FeS2 dosage of 6% and a roasting temperature of 1000 ℃ with a S/Fe molar ratio of 0.125 and an iron metallization rate of 91.76% exhibited the best performance for removing methyl orange. Core-shell structure S-nZVI was successfully synthesized on SiO2 surfaces in the SiO2@S-nZVI, where ZVI derived from iron mineral reduction reacted with S2 released by pyrite decomposition during carbothermal reduction process. The incorporation of S into both the surface and the bulk of ZVI accelerates electron transfer, while the carrier SiO2 inhibits the aggregation of S-nZVI, thereby significantly enhancing the material’s pollutant removal performance. The degradation kinetics of organic contaminants were studied under various conditions, and the results showed that SiO2@S-nZVI can degrade methyl orange, acid orange G, methylene blue, and p-nitrophenol efficiently. The degradation mechanism analysis reveals that a redox reaction occurs between SiO2@S-nZVI and methyl orange, leading to the cleavage of the azo double bond in methyl orange and its subsequent degradation and mineralization. These findings offer a cost-effective method for the preparation of highly reactive S-nZVI.
{"title":"Carbothermal synthesis of quartz-supported S-nZVI from limonite and pyrite for enhanced organic pollutant degradation","authors":"Jiangan Chen , Ting Liao , Meian Wang , Mingxing Cheng , Danliang Zeng , Zuocheng Yuan , Wen Yu , Ying Ye , Wenjie Zhang , Qiongyao Tang , Chengdu Qi","doi":"10.1016/j.mineng.2026.110111","DOIUrl":"10.1016/j.mineng.2026.110111","url":null,"abstract":"<div><div>Sulfidized nano zero-valent iron (S-nZVI) is an exceptional wastewater treatment material, but its excessively high preparation costs severely restrict its industrial applications. In this study, a carbothermal reduction method was developed to prepare quartz-supported S-nZVI (SiO<sub>2</sub>@S-nZVI) from limonite ore and pyrite. The preparation conditions, characteristics, preparation mechanism of SiO<sub>2</sub>@S-nZVI, and its performance in removing organic contaminants were investigated. Batch experiments revealed that SiO<sub>2</sub>@S-nZVI prepared under the conditions of an FeS<sub>2</sub> dosage of 6% and a roasting temperature of 1000 ℃ with a S/Fe molar ratio of 0.125 and an iron metallization rate of 91.76% exhibited the best performance for removing methyl orange. Core-shell structure S-nZVI was successfully synthesized on SiO<sub>2</sub> surfaces in the SiO<sub>2</sub>@S-nZVI, where ZVI derived from iron mineral reduction reacted with S<sub>2</sub> released by pyrite decomposition during carbothermal reduction process. The incorporation of S into both the surface and the bulk of ZVI accelerates electron transfer, while the carrier SiO<sub>2</sub> inhibits the aggregation of S-nZVI, thereby significantly enhancing the material’s pollutant removal performance. The degradation kinetics of organic contaminants were studied under various conditions, and the results showed that SiO<sub>2</sub>@S-nZVI can degrade methyl orange, acid orange G, methylene blue, and p-nitrophenol efficiently. The degradation mechanism analysis reveals that a redox reaction occurs between SiO<sub>2</sub>@S-nZVI and methyl orange, leading to the cleavage of the azo double bond in methyl orange and its subsequent degradation and mineralization. These findings offer a cost-effective method for the preparation of highly reactive S-nZVI.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":"239 ","pages":"Article 110111"},"PeriodicalIF":5.0,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146072444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1016/j.mineng.2026.110075
Anthony Tapfuma , Paul Mutimutema , Olga Bazhko , Siyabonga Nkabinde , Mpho Ledwaba , John M Kabangu , Natsayi Chiwaye , Elmar Muller , Gebhu Ndlovu
The hydrometallurgy discipline is shifting towards circular processing, resulting in sustainable solutions for managing residual tailings generated during gold processing becoming increasingly important. Gold tailings, typically characterised by fine particle sizes, high silica content, low residual gold concentrations and many other valuable metals, including heavy and critical metals, present both environmental challenges (water, air and soil pollution) and opportunities for valorisation. This review paper examines the reprocessing of fresh and historic tailings, including those dating back to the early 19th century, to recover gold and other valuable metals such as copper, uranium, rare earth elements, and critical metals. Treatment methods including cyanidation, thiosulfate, thiourea, and halide leaching are discussed, with comparisons drawn between their use in value addition to tailings. Some novel methods, such as bioleaching, glycine leaching and deep eutectic solvents, show promising results due to lower operational costs and environmental benefits. Advantages of tailings reprocessing include reduced environmental liabilities as well as potential economic gains, but challenges such as reagent consumption and scalability limit the application. Additionally, this review examines the reuse of barren tailings in road construction, brick manufacturing, and mine backfill. High SiO2 content, fine particle distribution, and low impurity levels (such as arsenic, lead, etc.) enhance their suitability for these applications. Finally, the paper outlines key regulatory frameworks and policy considerations that influence tailings management and reuse, emphasising the need for supportive legislation to encourage sustainable practices. The findings presented in this review are based on a structured and systematic literature review methodology involving comprehensive database searches, rigorous screening, and thematic synthesis. While the literature surveyed extends as far back as 1985, the primary results and data incorporated in this review predominantly originate from studies published in the 2000 s through to 2025 due to the limited information accessible from earlier decades. Overall, reprocessing and repurposing gold tailings align with green mining goals, offering both economic and environmental benefits to the mining sector.
{"title":"Gold tailing metal extraction and sustainable end-use: a closed-loop review","authors":"Anthony Tapfuma , Paul Mutimutema , Olga Bazhko , Siyabonga Nkabinde , Mpho Ledwaba , John M Kabangu , Natsayi Chiwaye , Elmar Muller , Gebhu Ndlovu","doi":"10.1016/j.mineng.2026.110075","DOIUrl":"10.1016/j.mineng.2026.110075","url":null,"abstract":"<div><div>The hydrometallurgy discipline is shifting towards circular processing, resulting in sustainable solutions for managing residual tailings generated during gold processing becoming increasingly important. Gold tailings, typically characterised by fine particle sizes, high silica content, low residual gold concentrations and many other valuable metals, including heavy and critical metals, present both environmental challenges (water, air and soil pollution) and opportunities for valorisation. This review paper examines the reprocessing of fresh and historic tailings, including those dating back to the early 19th century, to recover gold and other valuable metals such as copper, uranium, rare earth elements, and critical metals. Treatment methods including cyanidation, thiosulfate, thiourea, and halide leaching are discussed, with comparisons drawn between their use in value addition to tailings. Some novel methods, such as bioleaching, glycine leaching and deep eutectic solvents, show promising results due to lower operational costs and environmental benefits. Advantages of tailings reprocessing include reduced environmental liabilities as well as potential economic gains, but challenges such as reagent consumption and scalability limit the application. Additionally, this review examines the reuse of barren tailings in road construction, brick manufacturing, and mine backfill. High SiO<sub>2</sub> content, fine particle distribution, and low impurity levels (such as arsenic, lead, etc.) enhance their suitability for these applications. Finally, the paper outlines key regulatory frameworks and policy considerations that influence tailings management and reuse, emphasising the need for supportive legislation to encourage sustainable practices. The findings presented in this review are based on a structured and systematic literature review methodology involving comprehensive database searches, rigorous screening, and thematic synthesis. While the literature surveyed extends as far back as 1985, the primary results and data incorporated in this review predominantly originate from studies published in the 2000 s through to 2025 due to the limited information accessible from earlier decades. Overall, reprocessing and repurposing gold tailings align with green mining goals, offering both economic and environmental benefits to the mining sector.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":"239 ","pages":"Article 110075"},"PeriodicalIF":5.0,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146072442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Silver, commonly associated with lead–zinc sulfide ores, varies greatly in its counting coefficient in lead and zinc concentrates, typically being 0.85 and 0.20, respectively. Therefore, targeted enrichment of silver into lead concentrates can offer fatter economic benefits. To achieve this objective, the design of silver-friendly collectors is required. Herein, a targeted reagent design strategy for the lead-silver simultaneous enrichment was presented based on the coordination chemistry principles. The principal finding is that monothiophosphate and dithiophosphate—identified through systematic screening of thiosulfate, thiosulfonate, monothiophosphate, and dithiophosphate as candidate mineralophilic functional groups—exhibit superior performance for the selective recovery of galena and silver. The hydrophobic alkyl chain design reveals that the solvation free energy increases with chain elongation, and branched chains exhibit stronger hydrophobicity than straight ones. The rationally designed reagents, di-isobutyl monothiophosphate (DIBMTP) and di-isobutyl dithiophosphate (DIBDTP), possess large HOMO-LUMO energy gaps, effectively preventing them from self-reacting to form dimers, in marked contrast to xanthates that readily form dixanthogens under similar conditions. Notably, DIBMTP and DIBDTP exhibit distinct interfacial coordination mechanisms with galena and silver minerals. Specifically, the coordination bonding with galena involves conventional orbital bonding, while that with argentite and elemental silver features orbital backbonding interactions, albeit differing in electron contributions between the Ag+ of argentite and Ag0 of elemental silver.
{"title":"Targeted enrichment of associated silver minerals in lead–zinc sulfide ores: Reagent design guided by coordination chemistry principles","authors":"Hongliang Zhang , Heng Yu , Xin Rao , Wei Sun , Chenyang Zhang","doi":"10.1016/j.mineng.2026.110101","DOIUrl":"10.1016/j.mineng.2026.110101","url":null,"abstract":"<div><div>Silver, commonly associated with lead–zinc sulfide ores, varies greatly in its counting coefficient in lead and zinc concentrates, typically being 0.85 and 0.20, respectively. Therefore, targeted enrichment of silver into lead concentrates can offer fatter economic benefits. To achieve this objective, the design of silver-friendly collectors is required. Herein, a targeted reagent design strategy for the lead-silver simultaneous enrichment was presented based on the coordination chemistry principles. The principal finding is that monothiophosphate and dithiophosphate—identified through systematic screening of thiosulfate, thiosulfonate, monothiophosphate, and dithiophosphate as candidate mineralophilic functional groups—exhibit superior performance for the selective recovery of galena and silver. The hydrophobic alkyl chain design reveals that the solvation free energy increases with chain elongation, and branched chains exhibit stronger hydrophobicity than straight ones. The rationally designed reagents, di-isobutyl monothiophosphate (DIBMTP) and di-isobutyl dithiophosphate (DIBDTP), possess large HOMO-LUMO energy gaps, effectively preventing them from self-reacting to form dimers, in marked contrast to xanthates that readily form dixanthogens under similar conditions. Notably, DIBMTP and DIBDTP exhibit distinct interfacial coordination mechanisms with galena and silver minerals. Specifically, the coordination bonding with galena involves conventional orbital bonding, while that with argentite and elemental silver features orbital backbonding interactions, albeit differing in electron contributions between the Ag<sup>+</sup> of argentite and Ag<sup>0</sup> of elemental silver.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":"239 ","pages":"Article 110101"},"PeriodicalIF":5.0,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146072447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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