Pub Date : 2024-10-15DOI: 10.1016/j.mineng.2024.109050
Acid surface pretreatment was employed to realize the selective hydrophobic agglomeration of micro-fine ilmenite in flotation. Microflotation and artificially mixed mineral experiments manifested that after acid surface pretreatment, the recovery of micro-fine ilmenite with the increase of NaOL concentration and the floatability difference of micro-fine ilmenite and titanaugite increased significantly. Zeta potential and contact angle analyses suggested that acid surface pretreatment intensified the adsorption of NaOL on ilmenite surfaces while reducing it on titanaugite surfaces. Turbidity, optical microscope, and EDLVO theory analyses attested that the hydrophobic attraction dominated in a short particle spacing in NaOL solution. Following acid surface pretreatment, the hydrophobic agglomeration between micro-fine ilmenite particles enhanced in NaOL solution due to increased hydrophobic attraction. In contrast, the hydrophobic attraction and agglomeration between micro-fine titanaugite particles as well as between micro-fine ilmenite and titanaugite particles weakened. Overall, acid surface pretreatment improved the selective adsorption of NaOL and the selective hydrophobic agglomeration of micro-fine ilmenite, resulting in enhanced separation efficiency and recovery of micro-fine ilmenite.
{"title":"Impact of acid surface pretreatment on the hydrophobic agglomeration of micro-fine ilmenite and titanaugite in flotation","authors":"","doi":"10.1016/j.mineng.2024.109050","DOIUrl":"10.1016/j.mineng.2024.109050","url":null,"abstract":"<div><div>Acid surface pretreatment was employed to realize the selective hydrophobic agglomeration of micro-fine ilmenite in flotation. Microflotation and artificially mixed mineral experiments manifested that after acid surface pretreatment, the recovery of micro-fine ilmenite with the increase of NaOL concentration and the floatability difference of micro-fine ilmenite and titanaugite increased significantly. Zeta potential and contact angle analyses suggested that acid surface pretreatment intensified the adsorption of NaOL on ilmenite surfaces while reducing it on titanaugite surfaces. Turbidity, optical microscope, and EDLVO theory analyses attested that the hydrophobic attraction dominated in a short particle spacing in NaOL solution. Following acid surface pretreatment, the hydrophobic agglomeration between micro-fine ilmenite particles enhanced in NaOL solution due to increased hydrophobic attraction. In contrast, the hydrophobic attraction and agglomeration between micro-fine titanaugite particles as well as between micro-fine ilmenite and titanaugite particles weakened. Overall, acid surface pretreatment improved the selective adsorption of NaOL and the selective hydrophobic agglomeration of micro-fine ilmenite, resulting in enhanced separation efficiency and recovery of micro-fine ilmenite.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441745","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 : 2024-10-14DOI: 10.1016/j.mineng.2024.109042
The global shift towards electrification has led to an unprecedented demand for lithium (Li) – a key element in Li-ion battery technology. Sedimentary claystones found in Nevada have recently emerged as a new resource for Li. However, these claystones pose challenges to process due to their intricate and complex mineral composition. One of the significant challenges is that the claystones contain significant amounts of carbonate minerals such as calcite, which results in excessive processing reagent consumption. This study investigates the application of centrifugation as a gravity separation method for removing calcite from one Nevada sedimentary claystone. By varying the centrifugation time and rotation speed (RPM), a maximum of 81 % Li recovery with 82 % calcium (Ca) rejection can be obtained in the clay fraction. The study also showed that the beneficiation can reduce acid consumption during the leaching process by approximately 14 %. This study not only validates centrifugation as an effective technique to upgrade the Li sedimentary claystones, but also encourages further research of advanced gravity separation technologies for the pre-treatment of Li-bearing sedimentary claystones.
{"title":"Beneficiation of Li-bearing sedimentary claystone by centrifugation","authors":"","doi":"10.1016/j.mineng.2024.109042","DOIUrl":"10.1016/j.mineng.2024.109042","url":null,"abstract":"<div><div>The global shift towards electrification has led to an unprecedented demand for lithium (Li) – a key element in Li-ion battery technology. Sedimentary claystones found in Nevada have recently emerged as a new resource for Li. However, these claystones pose challenges to process due to their intricate and complex mineral composition. One of the significant challenges is that the claystones contain significant amounts of carbonate minerals such as calcite, which results in excessive processing reagent consumption. This study investigates the application of centrifugation as a gravity separation method for removing calcite from one Nevada sedimentary claystone. By varying the centrifugation time and rotation speed (RPM), a maximum of 81 % Li recovery with 82 % calcium (Ca) rejection can be obtained in the clay fraction. The study also showed that the beneficiation can reduce acid consumption during the leaching process by approximately 14 %. This study not only validates centrifugation as an effective technique to upgrade the Li sedimentary claystones, but also encourages further research of advanced gravity separation technologies for the pre-treatment of Li-bearing sedimentary claystones.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434125","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 : 2024-10-10DOI: 10.1016/j.mineng.2024.109022
Nickel sulfide concentrate was an important raw material for battery-grade nickel sulfate. To efficiently separate nickel from saprolitic laterite to product nickel sulfide concentrate, a novel and clean sulfidation-flotation process aimed to enhance selective sulfidation and particle growth through sodium carbonate was proposed herein. The effects of temperature, time, sulfur dosage, Na salts, and carbon additions on the selective sulfidation of nickel are systematically studied. Experimental results show that sodium carbonate can destroy the silicate structure, release nickel in the silicate, and form a low-melting point phase, promoting the aggregation of nickel sulfide, thereby achieving the purpose of promoting the sulfidation of nickel and the growth of synthetic nickel matte particles. Under the optimal conditions, 85.7% Ni and 27.1% Fe could be sulfated.
{"title":"Intensifying the selective sulfidation of nickel in saprolitic laterites by sodium salts","authors":"","doi":"10.1016/j.mineng.2024.109022","DOIUrl":"10.1016/j.mineng.2024.109022","url":null,"abstract":"<div><div>Nickel sulfide concentrate was an important raw material for battery-grade nickel sulfate. To efficiently separate nickel from saprolitic laterite to product nickel sulfide concentrate, a novel and clean sulfidation-flotation process aimed to enhance selective sulfidation and particle growth through sodium carbonate was proposed herein. The effects of temperature, time, sulfur dosage, Na salts, and carbon additions on the selective sulfidation of nickel are systematically studied. Experimental results show that sodium carbonate can destroy the silicate structure, release nickel in the silicate, and form a low-melting point phase, promoting the aggregation of nickel sulfide, thereby achieving the purpose of promoting the sulfidation of nickel and the growth of synthetic nickel matte particles. Under the optimal conditions, 85.7% Ni and 27.1% Fe could be sulfated.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422007","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 : 2024-10-10DOI: 10.1016/j.mineng.2024.109016
The recovery of valuable minerals in froth flotation industry relies on finding inexpensive and environmentally friendly reagents that selectively adsorb upon surfaces and interfaces. Computer simulations, especially when extended, provide access to detailed mechanistic information on solvent configurations and may ascertain crucial dynamical events over the adsorption process. Further, in silico throughput screening can prevent both the high cost of experiments and the related risks to the environment. Yet, a better compromise between accuracy and computational cost must be met. Machine learning (ML) simulations may ease the latter and suggest solidophilic reagents able to improve the flotation efficiency, shedding new light on discerning descriptors able to accurately capture the nature of the molecule-surface interaction. In this work, our recent advancements in modeling of new accurate mineral-water interfaces based on active learning of ab initio molecular dynamics trajectories have been introduced. The case of some habitual oxides and minerals liberated in mining industry will be taken as examples.
在泡沫浮选工业中回收有价值的矿物有赖于找到能选择性吸附表面和界面的廉价环保试剂。计算机模拟，尤其是扩展模拟，可提供有关溶剂配置的详细机理信息，并可确定吸附过程中的关键动态事件。此外，硅学高通量筛选可以避免高昂的实验成本和相关的环境风险。然而，必须在准确性和计算成本之间取得更好的平衡。机器学习（ML）模拟可以缓解后者的问题，并提出能够提高浮选效率的亲固试剂，为辨别能够准确捕捉分子与表面相互作用性质的描述符提供新的思路。在这项工作中，介绍了我们最近在基于主动学习 ab initio 分子动力学轨迹的新型精确矿物-水界面建模方面取得的进展。我们将以采矿业中释放的一些常见氧化物和矿物为例。
{"title":"Enhanced Machine Learning Molecular Simulations for optimization of flotation selectivity: A perspective paper","authors":"","doi":"10.1016/j.mineng.2024.109016","DOIUrl":"10.1016/j.mineng.2024.109016","url":null,"abstract":"<div><div>The recovery of valuable minerals in froth flotation industry relies on finding inexpensive and environmentally friendly reagents that selectively adsorb upon surfaces and interfaces. Computer simulations, especially when extended, provide access to detailed mechanistic information on solvent configurations and may ascertain crucial dynamical events over the adsorption process. Further, in silico throughput screening can prevent both the high cost of experiments and the related risks to the environment. Yet, a better compromise between accuracy and computational cost must be met. Machine learning (ML) simulations may ease the latter and suggest solidophilic reagents able to improve the flotation efficiency, shedding new light on discerning descriptors able to accurately capture the nature of the molecule-surface interaction. In this work, our recent advancements in modeling of new accurate mineral-water interfaces based on active learning of ab initio molecular dynamics trajectories have been introduced. The case of some habitual oxides and minerals liberated in mining industry will be taken as examples.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-08DOI: 10.1016/j.mineng.2024.109024
Base metals are among the key drivers propelling the economy’s expansion due to their widespread uses and applications. They are used as input factors in the construction of houses, transportation, plants, machinery, pipes, electrical cables, etc. As high-grade base metal sulphide deposits continue to diminish rapidly, the focus is shifting towards recovering these metals from lower grade oxidised and mixed ore deposits. This article critically discusses several research attempts made on the pretreatment of oxidised and mixed ores to increase base metal recoveries by froth flotation, as well as their benefits and drawbacks. Finally, the paper proposes further research and suggest steps forward to pretreatment of oxidised base metals. It is strongly believed that with proper pretreatment of oxidised base metals prior to flotation, when established as a viable technology recognised by industry, will contribute to the sustainability of base metal industry.
{"title":"Pretreatment and recovery of base metals from oxidised ores by froth flotation technology – A review","authors":"","doi":"10.1016/j.mineng.2024.109024","DOIUrl":"10.1016/j.mineng.2024.109024","url":null,"abstract":"<div><div>Base metals are among the key drivers propelling the economy’s expansion due to their widespread uses and applications. They are used as input factors in the construction of houses, transportation, plants, machinery, pipes, electrical cables, etc. As high-grade base metal sulphide deposits continue to diminish rapidly, the focus is shifting towards recovering these metals from lower grade oxidised and mixed ore deposits. This article critically discusses several research attempts made on the pretreatment of oxidised and mixed ores to increase base metal recoveries by froth flotation, as well as their benefits and drawbacks. Finally, the paper proposes further research and suggest steps forward to pretreatment of oxidised base metals. It is strongly believed that with proper pretreatment of oxidised base metals prior to flotation, when established as a viable technology recognised by industry, will contribute to the sustainability of base metal industry.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-08DOI: 10.1016/j.mineng.2024.109034
A sulfidic secondary raw material rich in Ni (millerite) and Zn (sphalerite) as well as mixed Ni-Fe-S sulfides was characterized and investigated for its leaching behavior under atmospheric direct acid leaching system utilizing air or oxygen, H2SO4, temperature ranges, and gas flow rates. The goal was to investigate extractability of the main elements (Ni, 15 wt% and Zn, 16 wt%) in the raw material whether both Ni and Zn could be extract simultaneously, or whether the material is more amenable to selective leaching, impacting the subsequent process options. Batch leaching experiments were performed in a 1 L and 0.5 L systems in two complementary leaching series. Ni was not appreciably extracted apart from the Ni sulfates present in the raw material apart from the experiments utilizing O2(g). The Ni dissolution did not readily occur until Zn extraction was finished and solution oxidation–reduction potential (ORP) increased to ca. 450 mV (vs. Ag/AgCl), and only reached ca. 50 % extraction at t = 24 h in T=90 °C and pH=1. The leach residue Zn content closely followed the ORP, achieving a minimum (0.1 wt% Zn) at E=471 mV (vs. Ag/AgCl). The most rapid leaching kinetics for ZnS was with excess acid, followed by experiments with O2(g). Decent kinetics were observed in response surface design of experiments (T=30, 50, 70 °C; m(H2SO4)/m(Raw material) = 0.6, 0.9, 1.2 g/g), allowing Zn extraction in < 6h. as it was possible to produce upgraded NiS (20 wt%) while extracting most of the Zn (99 %) under several experimental conditions, ranging from high T (90 °C) and limited constant acidity (pH 1) to low temperature (T=50 °C) and high excess acidity. It was shown that it is possible in an atmospheric process to selectively extract Zn while keeping majority of Ni in the leach residue. Selective extraction of Zn allows separation of Ni and Zn into separate materials feeds to be subsequently processed: Zn stream in a Zn process, and Ni-containing residue in a Ni smelter.
{"title":"Characterization and leaching options of a Zn and Ni-containing secondary sulfide","authors":"","doi":"10.1016/j.mineng.2024.109034","DOIUrl":"10.1016/j.mineng.2024.109034","url":null,"abstract":"<div><div>A sulfidic secondary raw material rich in Ni (millerite) and Zn (sphalerite) as well as mixed Ni-Fe-S sulfides was characterized and investigated for its leaching behavior under atmospheric direct acid leaching system utilizing air or oxygen, H<sub>2</sub>SO<sub>4</sub>, temperature ranges, and gas flow rates. The goal was to investigate extractability of the main elements (Ni, 15 wt% and Zn, 16 wt%) in the raw material whether both Ni and Zn could be extract simultaneously, or whether the material is more amenable to selective leaching, impacting the subsequent process options. Batch leaching experiments were performed in a 1 L and 0.5 L systems in two complementary leaching series. Ni was not appreciably extracted apart from the Ni sulfates present in the raw material apart from the experiments utilizing O<sub>2</sub>(g). The Ni dissolution did not readily occur until Zn extraction was finished and solution oxidation–reduction potential (ORP) increased to <em>ca.</em> 450 mV (vs. Ag/AgCl), and only reached <em>ca.</em> 50 % extraction at t = 24 h in <em>T</em>=90 °C and pH=1. The leach residue Zn content closely followed the ORP, achieving a minimum (0.1 wt% Zn) at E=471 mV (vs. Ag/AgCl). The most rapid leaching kinetics for ZnS was with excess acid, followed by experiments with O<sub>2</sub>(g). Decent kinetics were observed in response surface design of experiments (<em>T=</em>30, 50, 70 °C; m<sub>(H2SO4)</sub>/m<sub>(Raw material)</sub> = 0.6, 0.9, 1.2 g/g), allowing Zn extraction in < 6h. as it was possible to produce upgraded NiS (20 wt%) while extracting most of the Zn (99 %) under several experimental conditions, ranging from high T (90 °C) and limited constant acidity (pH 1) to low temperature (T=50 °C) and high excess acidity. It was shown that it is possible in an atmospheric process to selectively extract Zn while keeping majority of Ni in the leach residue. Selective extraction of Zn allows separation of Ni and Zn into separate materials feeds to be subsequently processed: Zn stream in a Zn process, and Ni-containing residue in a Ni smelter.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07DOI: 10.1016/j.mineng.2024.109039
High-pressure grinding rolls (HPGR) is an energy-efficient size reduction equipment widely used in the mining industry. Simulating and analyzing its performance is of significant importance. This paper focuses on the comminution process of HPGR and simulates it using the discrete element method (DEM) and particle replacement model (PRM). Furthermore, the combination of DEM simulation and Box-Behnken designs (BBD) is employed. The effects of roll diameter, roll width, operating gap, and roll speed on HPGR performance are investigated using analysis of variance (ANOVA) and response surface methodology (RSM). A performance prediction model is established through regression analysis, and numerical optimization of performance indicators under different weight ratios is conducted. The results indicate that rolls with a high aspect ratio generally achieve better performance. In addition, the effect of feed particle size on throughput and power is negatively correlated, while the effect on product fineness is not obvious. Based on this, dynamic adjustments of the operating gap, roll speed and feed particle size can be made to meet the optimal design of HPGR performance.
{"title":"Simulation and analysis of high-pressure grinding rolls performance based on DEM-PRM","authors":"","doi":"10.1016/j.mineng.2024.109039","DOIUrl":"10.1016/j.mineng.2024.109039","url":null,"abstract":"<div><div>High-pressure grinding rolls (HPGR) is an energy-efficient size reduction equipment widely used in the mining industry. Simulating and analyzing its performance is of significant importance. This paper focuses on the comminution process of HPGR and simulates it using the discrete element method (DEM) and particle replacement model (PRM). Furthermore, the combination of DEM simulation and Box-Behnken designs (BBD) is employed. The effects of roll diameter, roll width, operating gap, and roll speed on HPGR performance are investigated using analysis of variance (ANOVA) and response surface methodology (RSM). A performance prediction model is established through regression analysis, and numerical optimization of performance indicators under different weight ratios is conducted. The results indicate that rolls with a high aspect ratio generally achieve better performance. In addition, the effect of feed particle size on throughput and power is negatively correlated, while the effect on product fineness is not obvious. Based on this, dynamic adjustments of the operating gap, roll speed and feed particle size can be made to meet the optimal design of HPGR performance.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422005","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 : 2024-10-05DOI: 10.1016/j.mineng.2024.109040
The workability of alkali-activated coal gasification slag (CGS) based backfill materials is critical parameter in transportation processes, while the high water demand of CGS hinders its application due to its high specific surface area. This study utilizes acetic acid (AA) as a preconditioner to modify the surface characteristics of CGS, aiming to optimize the rheology of alkali-activated CGS backfill pastes (AAC). The shear stress, viscosity, thixotropic property, and zeta potential of AAC, and mineral composition and surface morphology of AA-modified CGS at various AA dosages were systematically investigated. It is found that the yield stress, plastic viscosity, and hysteresis loop area of AAC reaches the lowest value at 4 wt% AA dosage on the basis of the CGS, owing to AA reacts with the minerals on the surface of CGS particles, and then the AA is adsorbed on the CGS particles and acts as a surfactant, which increases the static electricity between CGS particles. However, the yield stress of AAC increases significantly when the AA dosage exceeds 4 wt%, attributing to the smaller particle size resulting from AA modification, which raises water demand. This investigation proposes a novel approach for optimizing the rheology of CGS based AAC and provides theoretical guidance for employing modified CGS as backfill materials.
基于碱活化煤气化炉渣（CGS）的回填材料的可操作性是运输过程中的关键参数，而 CGS 的高比表面积使其高需水量阻碍了其应用。本研究利用醋酸（AA）作为前处理剂来改变 CGS 的表面特性，旨在优化碱激活 CGS 回填浆料（AAC）的流变性。系统研究了不同 AA 用量下 AAC 的剪切应力、粘度、触变性和 Zeta 电位，以及 AA 改性 CGS 的矿物组成和表面形态。研究发现，在 CGS 的基础上，当 AA 用量为 4 wt% 时，AAC 的屈服应力、塑性粘度和滞后环面积达到最低值，这是由于 AA 与 CGS 颗粒表面的矿物发生反应，然后 AA 被吸附在 CGS 颗粒上，起到表面活性剂的作用，从而增加了 CGS 颗粒间的静电。然而，当 AA 用量超过 4 wt% 时，AAC 的屈服应力会显著增加，原因是 AA 改性后粒径变小，从而提高了需水量。这项研究提出了一种优化基于 CGS 的 AAC 流变性能的新方法，并为将改性 CGS 用作回填材料提供了理论指导。
{"title":"Using acetic acid as a preconditioner to optimize rheology of alkali-activated coal gasification slag based backfill pastes","authors":"","doi":"10.1016/j.mineng.2024.109040","DOIUrl":"10.1016/j.mineng.2024.109040","url":null,"abstract":"<div><div>The workability of alkali-activated coal gasification slag (CGS) based backfill materials is critical parameter in transportation processes, while the high water demand of CGS hinders its application due to its high specific surface area. This study utilizes acetic acid (AA) as a preconditioner to modify the surface characteristics of CGS, aiming to optimize the rheology of alkali-activated CGS backfill pastes (AAC). The shear stress, viscosity, thixotropic property, and zeta potential of AAC, and mineral composition and surface morphology of AA-modified CGS at various AA dosages were systematically investigated. It is found that the yield stress, plastic viscosity, and hysteresis loop area of AAC reaches the lowest value at 4 wt% AA dosage on the basis of the CGS, owing to AA reacts with the minerals on the surface of CGS particles, and then the AA is adsorbed on the CGS particles and acts as a surfactant, which increases the static electricity between CGS particles. However, the yield stress of AAC increases significantly when the AA dosage exceeds 4 wt%, attributing to the smaller particle size resulting from AA modification, which raises water demand. This investigation proposes a novel approach for optimizing the rheology of CGS based AAC and provides theoretical guidance for employing modified CGS as backfill materials.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422004","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 : 2024-10-04DOI: 10.1016/j.mineng.2024.109018
Froth flotation uses air bubbles to separate mineral particles based on the difference in mineral surface hydrophobicity. Collectors are needed to selectively hydrophobize the surface of targeted minerals to augment the difference in surface hydrophobicity between wanted minerals and unwanted ones. Here, we showed that this classical (well-established) principle fails to describe the flotation of water-soluble minerals. Our systematic micro-flotation tests using soluble minerals (NaCl and KCl crystals) in brines and three popular collectors (dodecylamine hydrochloride, sodium dodecylsulfate, and sodium laurate) showed a substantial flotation recovery of the salt minerals without detected collector adsorption at the mineral surfaces by X-ray photoelectron spectroscopy (XPS). Complementary particle size distribution measurement indicated the occurrence of sub-micron collector colloids in saturated brines. Moreover, the flotation recovery agreed well with the measured contact angle, suggesting the attraction between bubble-bound collector colloids and salt crystal surfaces. These paradoxical results signify a new principle underlying the flotation of soluble minerals, i.e., the selective colloidal attraction between bubble-bound collector colloids and salt particles enables the flotation separation of soluble minerals.
浮选利用气泡根据矿物表面疏水性的差异来分离矿物颗粒。需要捕收剂来选择性地疏水目标矿物的表面，以增加想要的矿物和不想要的矿物之间的表面疏水性差异。在这里，我们证明了这一经典（已确立的）原理无法描述水溶性矿物的浮选。我们使用盐水中的可溶性矿物（氯化钠和氯化钾晶体）和三种常用的捕收剂（十二烷基胺盐酸盐、十二烷基硫酸钠和月桂酸钠）进行了系统的微浮选试验，结果表明盐类矿物的浮选回收率很高，而且用 X 射线光电子能谱（XPS）检测矿物表面没有捕收剂吸附。粒度分布测量结果表明，饱和盐水中存在亚微米级的捕收剂胶体。此外，浮选回收率与测量的接触角非常吻合，这表明气泡结合的捕收胶体与盐晶体表面之间存在吸引力。这些自相矛盾的结果表明了可溶性矿物浮选的一个新原理，即气泡结合的捕收胶体与盐颗粒之间的选择性胶体吸引力使可溶性矿物得以浮选分离。
{"title":"Soluble mineral flotation paradox: Improved recovery with no sign of collector adsorption on minerals signifies colloidal attraction between bubble-bound collector colloids and mineral particles","authors":"","doi":"10.1016/j.mineng.2024.109018","DOIUrl":"10.1016/j.mineng.2024.109018","url":null,"abstract":"<div><div>Froth flotation uses air bubbles to separate mineral particles based on the difference in mineral surface hydrophobicity. Collectors are needed to selectively hydrophobize the surface of targeted minerals to augment the difference in surface hydrophobicity between wanted minerals and unwanted ones. Here, we showed that this classical (well-established) principle fails to describe the flotation of water-soluble minerals. Our systematic micro-flotation tests using soluble minerals (NaCl and KCl crystals) in brines and three popular collectors (dodecylamine hydrochloride, sodium dodecylsulfate, and sodium laurate) showed a substantial flotation recovery of the salt minerals without detected collector adsorption at the mineral surfaces by X-ray photoelectron spectroscopy (XPS). Complementary particle size distribution measurement indicated the occurrence of sub-micron collector colloids in saturated brines. Moreover, the flotation recovery agreed well with the measured contact angle, suggesting the attraction between bubble-bound collector colloids and salt crystal surfaces. These paradoxical results signify a new principle underlying the flotation of soluble minerals, i.e., the selective colloidal attraction between bubble-bound collector colloids and salt particles enables the flotation separation of soluble minerals.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-04DOI: 10.1016/j.mineng.2024.109023
Re-mining unextracted metals from mine tailings can contribute to sustaining society’s high demand for metals. Electrodialysis (ED) is a promising, yet underdeveloped, extraction technology for mobilizing and transporting particle-bound elements in a suspension slurry. This study investigated ED for extraction of copper (Cu), lead (Pb) and zinc (Zn) from Cu mine tailings (concentration of Cu: 2039 mg/kg, feldspar-dominant) and Pb-Zn mine tailings (Pb: 4469 mg/kg, Zn: 19417 mg/kg, dolomite-dominant). A multivariate experimental design was used to examine the effect of varying current density (1–5 mA/cm2) and operation time (24–336 h) of 40 bench-scale experiments. The maximum extractions obtained were 70 % Cu from the Cu mine tailings and 97 % Pb and 88 % Zn from the Pb-Zn mine tailings. Depending on the tailing, the extraction was influenced differently by current density and operation time. In particular, carbonate minerals such as dolomite and calcite delayed acidification and thus the extraction due to their buffering capacity. However, as the carbonaceous tailings contained a larger proportion of soluble metals, likely to be bound in the carbonates themselves, overall higher metal extraction was obtained from these. Thresholds above, for which the increase of current densities did not increase extraction, were observed at 2 and 4 mA/cm2 for the Cu and Pb-Zn tailings, respectively. The solubility of the remaining metals in the treated tailings increased significantly due to acidification by the EDR process and utilization of the treated tailings in construction materials therefore needs further investigation.
{"title":"Electrodialytic extraction of copper, lead and zinc from sulfide mine tailings: Optimization of current density and operation time","authors":"","doi":"10.1016/j.mineng.2024.109023","DOIUrl":"10.1016/j.mineng.2024.109023","url":null,"abstract":"<div><div>Re-mining unextracted metals from mine tailings can contribute to sustaining society’s high demand for metals. Electrodialysis (ED) is a promising, yet underdeveloped, extraction technology for mobilizing and transporting particle-bound elements in a suspension slurry. This study investigated ED for extraction of copper (Cu), lead (Pb) and zinc (Zn) from Cu mine tailings (concentration of Cu: 2039 mg/kg, feldspar-dominant) and Pb-Zn mine tailings (Pb: 4469 mg/kg, Zn: 19417 mg/kg, dolomite-dominant). A multivariate experimental design was used to examine the effect of varying current density (1–5 mA/cm<sup>2</sup>) and operation time (24–336 h) of 40 bench-scale experiments. The maximum extractions obtained were 70 % Cu from the Cu mine tailings and 97 % Pb and 88 % Zn from the Pb-Zn mine tailings. Depending on the tailing, the extraction was influenced differently by current density and operation time. In particular, carbonate minerals such as dolomite and calcite delayed acidification and thus the extraction due to their buffering capacity. However, as the carbonaceous tailings contained a larger proportion of soluble metals, likely to be bound in the carbonates themselves, overall higher metal extraction was obtained from these. Thresholds above, for which the increase of current densities did not increase extraction, were observed at 2 and 4 mA/cm<sup>2</sup> for the Cu and Pb-Zn tailings, respectively. The solubility of the remaining metals in the treated tailings increased significantly due to acidification by the EDR process and utilization of the treated tailings in construction materials therefore needs further investigation.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":null,"pages":null},"PeriodicalIF":4.9,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142422002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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