Arsenic-containing desulfurization gypsum (ADG) is a typical solid waste in the metallurgical industry, and its resource utilization is restricted by the high toxicity and difficulty in removal of arsenic. In this work, using ADG as the raw material, the effects of pressurized hydrothermal conditions on the conversion of alpha-hemihydrate gypsum (alpha-HH) and simultaneous arsenic removal were systematically investigated. The results showed that hydrothermal temperature, reaction time, sulfuric acid concentration, and liquid-solid ratio (L/S) all had significant impacts on the crystal form of the product and arsenic removal efficiency. Under the conditions of 140 degrees C, 5 % H2SO4, reaction duration of 120 min, and L/S of 7:1, gypsum could be completely converted into dense columnar alpha-HH, and the arsenic removal rate reached 95.7 %. H+ could directionally destroy the lattice of Ca-As compounds, enabling arsenic to migrate to the liquid phase in a dissolved state; meanwhile, the phase transformation from calcium sulfate dihydrate (DH) to alpha-HH was completed simultaneously during the dissolutionrecrystallization process. The arsenic removal process was controlled by chemical reaction in the initial stage and then turned into diffusion control. The arsenic removal process conformed to the Avrami model ( - ln(1 c) = 8.47exp( - 21080/RT)t0.47), with an activation energy of 21.1 kJ/mol. Aluminum sulfate crystal modifier could effectively regulate the crystal form of alpha-HH and improve arsenic removal efficiency. This study reveals the action law of pressurized hydrothermal conditions on alpha-HH conversion and simultaneous arsenic removal as well as the characteristics of mass transfer control, providing a theoretical basis for the synergistic high-value and harmless utilization of ADG.

Flotation is an effective route for recovering fine cassiterite, yet its selective separation from calcite remains challenging because both minerals show similar responses in fatty-acid collector systems. In this work, a synergistic depressant system combining Cu2+ and CMC was developed to selectively separate cassiterite from calcite. To evaluate this reagent scheme and clarify its surface-modification mechanism, a suite of analytical techniques was employed, including micro-flotation experiments, kinetic modeling, solution-speciation calculations, contact-angle and zeta-potential measurements, FTIR, XPS, AFM, and DFT simulations. The Cu2+-CMC system markedly increased the flotation selectivity between the two minerals. Under the optimal reagent conditions, an SnO2 concentrate grade of 83.42% with a corresponding recovery of 86.21% was achieved, whereas the recovery of CaCO3 was limited to only 14.94%. Surface analyses revealed that the Cu2+-CMC system preferentially adsorbed on calcite, reducing its NaOL-induced contact angle from 81.4 degrees to 43.2 degrees and forming a stable hydrophilic overlayer with increased surface roughness. Mechanistically, CMC complexed with pre-adsorbed hydrolyzed Cu species on calcite through carboxyl groups, thereby enhancing adsorption stability, strengthening calcite depression, and preserving cassiterite floatability. This study provides an effective approach for the selective flotation recovery of cassiterite from calcite-rich systems.

Inspired by the initial mineralization process with bone matrix vesicles (MVs), this study innovatively developed a delivery system to mediate mineralization during bone regeneration. The system comprises nanofibrous chitosan microspheres (NCM) and poly (allylamine hydrochloride)-stabilized amorphous calcium phosphate (PAH-ACP), which is thereafter referred to as NCMP. NCM is synthesized through the thermal induction of chitosan molecular chains, serving as the carrier, while PAH-ACP functions as the mineralization precursor. Additionally, the nanofibrous network of NCMP mimics the architecture of natural extracellular matrix (ECM), creating an optimal niche for the active adhesion of stem cells to its surface, exhibiting good biocompatibility, immunoregulation, and osteogenic performance. In vivo, NCMP effectively recruits cells and mineralizes collagen, modulates cell behavior and differentiation, and promotes in situ biomineralization in rat calvarial defects. These results underscore the dual efficacy of NCMP not only as an effective delivery system for mineralization precursors but also as ECM-mimicking bio-blocks, offering a promising avenue for enhancing the repair and regeneration of bone defects.

Collectors serve as critical components in froth flotation processes. This study synthesized and evaluated three hydroxamic acid collectors for cassiterite separation through rational molecular design incorporating functional group enhancement, carbon chain extension, and isomerism principles. Density functional theory (DFT) simulations and quantum chemical analyses, including spatial configuration optimization, Mulliken charge distribution, electrostatic potential mapping, Fukui function analysis, and frontier molecular orbital calculations, were systematically employed to investigate collector-mineral interactions. Surface adsorption energy computations identified three optimized collectors, with subsequent adsorption modeling elucidating mineral surface interaction mechanisms. Flotation tests demonstrated that 2-BPA, PTPA, and PMBA showed greater affinity for cassiterite than BHA under neutral conditions, while all had a low calcite recovery rate of less than 15 % in neutral to alkaline conditions. Quantum chemical analyses revealed that both O and Sn atoms on the cassiterite surface act as potential active sites, while O atoms on the calcite surface exhibit high activity with electron deficient groups. Electrostatic potential and Fukui function analysis suggesting that O atom connected to N atom in the oxime group is more inclined to adsorb with the active sites on cassiterite surface. Theoretical calculations confirm these designed collectors enable effective cassiterite-calcite separation under optimized conditions. This work establishes fundamental design principles for flotation reagent development and provides theoretical frameworks for combined reagent systems in tin ore beneficiation.

In coal slime water treatment, traditional anionic polyacrylamide (APAM) faces challenges including difficulties in balancing charge density with hydrolysis degree and inadequate hydrophilicity. This study developed a plasma-modified APAM (P-APAM) and systematically investigated its enhancement mechanism for kaolinite particle flocculation and sedimentation. Experiments were performed with 5-20 s plasma treatments on APAM solutions, analyzing P-APAM properties such as viscosity, pH, conductivity, molecular chain structure, and functional group configuration. Parallel flocculation-sedimentation tests evaluated kaolinite treatment performance through settling velocity, supernatant turbidity, floc size, and Zeta potential measurements. Results revealed that 5 s plasma treatment strengthened hydrogen bonding while altering oxygen-containing functional group composition and arrangement in P-APAM molecules. The treatment promoted oxidative degradation of hydrophobic groups (-CH3/-CH2-), boosting hydration capacity and hydrophilicity while optimizing molecular chain flexibility and surface adaptability. The modified P-APAM formed compact floc structures (SK value = 0.612), achieving superior sedimentation rates, larger floc sizes, and enhanced flocculation efficiency at reduced dosages. Comprehensive experimental analysis confirmed that plasma-modified P-APAM substantially improved kaolinite flocculation and sedimentation performance. This research presents an innovative plasma-modified flocculant approach for clay mineral treatment in slime water, establishing an effective technical pathway for developing high-performance green flocculant systems with significant reference value for sustainable mineral processing.

In this paper, a new amidoxime compound, p-methylphenylethyl amidoxime (PEBH), was synthesized, and its flotation mechanism for separating azurite from quartz and calcite was studied. The results of flotation experiments showed that when the pH was 11 and the dosage of PEBH was 2.5 x 10-4-4 mol/L, the recovery and grade of azurite reached 94.32 % and 37.45 %, respectively. In contrast, the recovery of quartz is 11.97%, and the grade is only 18.83 %. The recovery rate of calcite is 19.10%, and the grade is only 2.54 %. Zeta test results show that the surface potential shift of azurite after PEBH treatment is much larger than that of quartz and calcite. It also proves that PEBH has a strong adsorption effect on the surface of azurite, while the adsorption effect on the surface of quartz and calcite is weak. XPS analysis results show that Cu2+ 2+ is the active site of PEBH adsorbed on the surface of azurite, and a stable five- membered chelating ring structure is formed after interaction. However, this obvious interaction did not occur on the surface of quartz and calcite. At the same time, the SEM-EDS test results also confirmed this view. Therefore, PEBH has the characteristics of high selectivity as a collector for azurite, making it a promising collector in the field of azurite flotation, providing a new choice for copper oxide recovery. (c) 2024 The Society of Powder Technology Japan. Published by Elsevier BV and The Society of Powder Technology Japan. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

The world's annual production of phosphogypsum (PG) is up to 200 million tons at present. It was found that 15 % of PG produced worldwide is recycled. Therefore, it is imperative to seek a new pathway to recycle PG. This work provides an overview of the state-of-the-art scheme for high-value utilization of PG. Compared with previously published works, this review focuses on the utilization of oxygen (O) and calcium (Ca) resources. The state-of-the-art technology of utilizing O in PG consists of lignite's chemical looping gasification (CLG) with PG-based oxygen carrier. The state-of-the-art technology for utilizing Ca in PG is the low-temperature decomposition of PG for producing CaO and CaCO3 from the reductive decomposition of PG. The process and the reaction mechanism of state-of-the-art technology for application of O and Ca in PG are summarized. Based on current research status, it is suggested to apply two or more solid wastes in cement, bricks and other aspects of large-scale. When utilizing PG, the migration transformation of impurities in PG and their reaction mechanisms at the molecular level deserve to be focused on. The key to solving the problems caused by PG large consumption, high value-added utilization and the introduction of policies providing incentives to this end. This research provides guidance for new engineering techniques for PG to achieve high-value and efficient use of resources in the large-scale utilisation of PG.

This study aims to evaluate the feasibility and safety of using municipal solid waste incineration fly ash (MSW-IFA) in the development of geopolymer-based solidification/stabilization (S/S) treatments. Geopolymers have garnered attention as a sustainable alternative to traditional cement, owing to their high strength, stability, and minimal CO2 emissions. In this study, a combination of experimental and simulation calculations was used to investigate the setting time, mechanical properties, environmental risks, hydration mechanisms and processes of municipal solid waste incineration fly ash-based polymeric functional cementitious materials (GFCM). The results demonstrate that the mechanical properties of GFCM are related to the changes in the mineral phases and the degree of compactness. Quantum chemical calculations indicate that the hydration products may be [Si(OH)4], [Al(OH)3(OH2)] and [Al(OH)4]-. It is possible that the heavy metals are embedded in the hydrated silica-aluminate by electrostatic interaction or chemisorption. Heavy metals may be embedded in hydrated silica-aluminate by electrostatic action or chemisorption. This study provides a feasible method for resource utilization and heavy metal stabilization mechanism of MSW-IFA.

Ammonium sulfate [(NH4)2SO4] is an effective activator of malachite sulfidization flotation. In this work, we explored the effects of ammonium ion (NH4+) and copper ion (Cu2+) on malachite sulfidization flotation and investigated the underlying mechanism. Flotation experiments demonstrated that NH4+ can not only eliminate the negative effects of Cu2+, but also work together with Cu2+ to further promote malachite sulfidization flotation in a certain concentration range. Zeta potential, SEM-EDS, and X-ray photoelectron spectroscopy analysis results indicated that the single Cu2+ weakened the oxidation of S (II) species on the malachite surface and reduced the formation of sulfides. In the presence of NH4+, Cu2+ did not inhibit the formation of sulfides on malachite surface but worked with NH4+ to promote it. Aqueous speciation calculation and adsorption test revealed that NH4+ and Cu2+ interacted to form Cu (II)-NH3 complexes, which reacts with S (II) species to form a copper sulfide substance that is more easily adsorbed on the malachite surface than the copper sulfide colloid formed by the reaction between Cu2+ and S (II) species. This leads to the improvement of surface sulfidization.

Sulfidization xanthate flotation remains the most promising method for the beneficiation of malachite. In this study, L-arginine (LA) was first used to modify the malachite surface and improve the efficiency of sulfidization flotation. The performance of LA was evaluated by the flotation experiments. The mechanism of interaction between LA and the malachite surface was investigated by adsorption experiments, zeta potential measurements, scanning electron microscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS) analysis. Flotation experiments showed that LA had a significantly promoting effect on malachite sulfidization flotation. Adsorption experiments and SEM-EDS results indicated that LA improved the adsorption of S (II) species into the malachite surface and promoted the formation of sulfides. This finding was further confirmed by the XPS analysis. The XPS measurements results determined that S (II) species reacted with Cu (II) on the malachite surface and form polysulfides, adding LA promoted the reaction. The zeta potential measurements showed that LA increased the positive electrical properties of the mineral surface, which was conducive to S (II) species adsorption and the sulfidization reaction. This work sheds new light on the development of sulfidization activation.

A combination depressant SHI was composed of sodium sulfite (Na2SO3) and sulfonated lignin (SL) in a 5:1 M ratio. In this study, SHI and sodium silicate (Na2SiO3) were employed to inhibit the floatability of galena, and the synergies between agents was explored. Micro-flotation results shown that after 2.4 x 10(-4) mol/L SHI was added, the recovery of galena and fine-galena declined by 53% and 36%, respectively. SHI exhibited excellent depressing efficiency toward galena. In the presence of Na2SiO3, the inhibitory effect of SHI was more obvious. Zeta potential measurements indicates that SHI and Na2SiO3 altered the potential of galena surface through chemical reaction or adsorption action. The X-ray photoelectron spectroscopy results demonstrate that Na2SiO3 in the SHI were reacted with Pb ions on the galena surface and formed PbSO3, the SL was adsorbed by the galena surface through hydrogen bonding. In parallel, Na2SiO3 interacted with the mineral surface by generating PbSiO3. The addition of inhibitors increased the oxidation rate of the galena surface, thereby reducing the adsorption of collectors. Density functional theory simulations shown that Na2SiO3 reduced the bonding energy between the galena surfaces and Na2SiO3, and improved the stability of adsorption.

针对孔雀石矿物亲水性强,常规硫化剂硫化作用后表面硫化膜不稳定的现状,开发出铜铵络合物作为强化硫化钠硫化作用的活化剂.试验结果表明:铜铵络合物在碱性条件下的主要作用成分为Cu(NH3)42+,该成分可起到与硫酸铵相似的活化效果,促使孔雀石表面覆盖的硫化物更均匀更致密,进而达到促进孔雀石表面疏水的效果.铜铵络合物应用于西藏玉龙氧化铜矿浮选过程时,在原矿含Cu 4.47％ 的条件下,经2粗2精2扫闭路浮选试验获得了氧化铜浮选精矿含铜24.14％、铜回收率82.15％的较好指标.

Ammonium sulfate ((NH4)(2)SO4) exhibits promoting effects in malachite sulfidization flotation. However, the promotion mechanism remains poorly understood. In this study, micro flotation tests, zeta-potential measurements, scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and materials studio simulation (DFT) were used to investigated the promotion mechanism of (NH4)(2)SO4. Micro-flotation test demonstrates that the recovery of malachite from 73% increased to 83%, when the (NH4)(2)SO4 was added. Contact angle and zeta potential test results indicate that addition of Na2S center dot 9H(2)O changes the surface properties of malachite and provide the conditions for adsorption of butyl xanthate (BX). After promoting the sulfidization by (NH4)(2)SO4, BX is more effective in improving the hydrophobicity. SEM-EDS and AFM results show that (NH4)(2)SO4 can improve performance and stability of sulfidization. X-ray photoelectron spectroscopy indicates that after sulfidization, polysulfides and cuprous were appeared in malachite surface, infers that a redox reaction occurs between sulfur and copper on the surface of malachite. After addition of (NH4)(2)SO4, the percentage of polysulfides and cuprous were increased, it implies (NH4)(2)SO4 can accelerate the redox reaction. Computational results show that after adding (NH4)(2)SO4, the adsorption energy of HS- on the malachite surface is reduced, implies that (NH4)(2)SO4 can improve the stability of HS-adsorption on the surface of malachite.

刚果(金)加丹加矿区硫氧混合型铜钴矿石含Cu 2.21％和Co 0.16％,铜钴元素均达到了工业回收标准,为确定合理高效的选矿工艺,进行了矿石性质分析及选矿试验研究.结果表明:该硫氧混合型铜钴矿石中的目的矿物种类复杂,目的元素铜除硫化铜和氧化铜形态赋存外,还有部分铜以铜锰铝硅氧化结合物中的铜形态赋存.钴主要以含钴黄铁矿及水钴矿形式赋存,脉石矿物主要以易泥化的碳酸盐类脉石为主.结合矿石性质分析和探索条件试验的结果确定了硫化矿物浮选—氧化矿物硫化钠硫化、组合捕收剂协同捕收浮选氧化铜矿物—氧化矿尾矿高梯度强磁选的选矿工艺,该工艺根据不同类型的目的矿物可浮性和磁性的差异性,分段产出硫化铜精矿、氧化铜精矿和磁选精矿三个产品,三个产品总铜回收率达到了91.54％,总钴回收率达到了56.48％,实现了对该硫氧混合型铜钴矿石主要元素的综合回收.

The interactions between water and oxide surfaces play an important role in many fields. In this work, the adsorption mechanism of water molecules on hematite (1 04) surface and the hydration microstructures were systematically investigated by means of FT-IR spectroscopy, X-ray photoelectron spectroscopy, and DFT calculations. The XPS measurements confirmed that water molecules can be chemically adsorbed on hematite surface, and the peak position of Fe3+ in the Fe 2p3/2 splitting peak is shifted to a high binding energy after hydration, which was confirmed by the computational results of partial density of state (PDOS) that the adsorption of water molecules can improve the energy of Fe 3d state in the surface approaching to that in the bulk. FT-IR analysis showed that the peak of O?H bending vibration was almost disappeared and the intensity of the O?H stretching vibration peak was significantly weakened after dehydration. The DFT calculations further indicated that about 30 water molecules can be well adsorbed on the hematite surface per unit nm2 area, resulting in hydroxyl hydration layer, the primary hydration layer, and the secondary hydration layer. This work sheds some new lights on the interface hydration of oxidized mineral.

•XPS and FT-IR measurements confirmed that water molecules could be chemically adsorbed on hematite surface.•The dissociative adsorption of water molecules on the hematite (104) surface is more advantageous.•A multilayer interface hydration model was proposed, including the hydroxyl hydration layer, the primary hydration layer, and the secondary hydration layer.

Sulfuration flotation is the most widely used technology in malachite beneficiation. However, the inhomogeneity of malachite surfaces usually results in a non-uniform sulfuration surface. The motivation of this work is attempt to adopt different functional combination collectors to enhance the sulfuration flotation of malachite. Accordingly, the flotation behaviors and adsorption mechanisms of benzohydroxamic acid (BHA) and sodium butyl-xanthate (SBX) on the surface of malachite were systematically investigated using flotation tests, zeta-potential measurements, Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, and first-principle calculations. The test results of vulcanization flotation showed that the combined collectors of SBX with BHA possessed a higher recovery than only using SBH by 20%, indicating that there may be a synergistic effect between BHA and SBX. The IR and Raman spectroscopy demonstrated that both BHA and SBX could chemically adsorb onto the malachite surface. The density functional theory (DFT) calculation results further indicated that the combined adsorption energy of BHA and SBX was much lower than that of only BHA or SBX, which confirmed the synergistic effects of BHA and SBX on the malachite surface. This work may shed new light on the design and development of more efficient combined flotation reagents.

In this study, the inhibitory effect of a composite depressant consisting of sodium sulfite and sodium lignosulfonate mixed at a molar ratio of 5:1 on Cu-Pb flotation separation was analyzed. The results of the mineral flotation tests show that both chalcopyrite and galena are floatable in a pH range of 6-12 and the composite depressant has a stronger inhibitory effect on galena than that of single inhibitors. The particle-size analyses of the concentrates and tailings show that it is difficult to inhibit the floatability of fine-grained galena using a single depressant, but the composite depressant can effectively deteriorate its floatability. The results obtained from zeta potential measurements and SEM reveal that the zeta potential of galena becomes more negative after a composite depressant is added because of the greater adsorption of sulfite and lignosulfonate ions on the surface of the galena. The XPS results show that sodium sulfite chemically reacts with the surface of galena and that hydrogen bonds are the main driving force of the adsorption of sodium lignosulfonate onto the surface of galena. The use of a combination of sodium sulfite and sodium lignosulfonate increases their adsorption onto the surface of fine-grained galena.