DFT research on activation of sphalerite

Activation of sphalerite ZnS, (Zn, Fe)S, (Zn, Cu)S were carried out using the density functional theory (DFT) method. The electronic structures and related properties of three kind of zinc sulfide compounds were investigated. In addition, the relation between electronic structure and flotation behavior was discussed. The results show that, ZnS has a broader band gap than (Zn,Cu)S and (Zn,Fe)S do, and it has low electrochemistry activity to react with flotation collectors to render the surface hydrophobic. When the Zn atom in ZnS is replaced by Cu atom,the band gap will be reduced, and the top valence band will be occupied by Cu 3d orbit, thus it is beneficial to the interaction between mineral surface and collector.     

闪锌矿(110)表面离子吸附的动力学模拟

为了查清高碱电位环境对闪锌矿表面性质抑制作用的根本原因 ,采用C2 Soterware分子力场中的万能力场方法 ,对闪锌矿 (110 )表面CaOH 和OH-两种离子的吸附进行了动力学模拟 ,并对吸附能和吸附质量云图进行了分析。模拟结果表明 ,相对于OH-来说 ,CaOH 在闪锌矿 (110 )表面的吸附能更负 ,吸附量更大。由此可知 ,这些吸附在表面的离子又与OH-和硫化矿氧化产物产生的SO2 -4等离子作用形成不溶性亲水表面产物 ,从而导致矿物受到抑制 ,这也正是高碱电位调控成功的原因之一。     

高铁闪锌矿高压酸浸过程中ZnS-FeS-H2O系的电位-pH图

对高铁闪锌矿高压酸浸的热力学过程进行了研究,并绘制了150℃、氧气压力为1 MPa时,浸出体系中ZnS-H2O系、FeS-H2O系、ZnS-FeS-H2O系的电位-pH图。     

Impact of gypsum supersaturated process water on the interactions between silica and zinc sulphide minerals

Flotation recovery and selectivity problems have been reported in the flotation of fine sulphide minerals in gypsum supersaturated process water. In this study, the effect of gypsum supersaturated solution on the interactions between silica and sphalerite (ZnS) minerals was examined by observing deposition behaviour of silica nanoparticles on sphalerite surface using a quartz crystal microbalance with dissipation (QCM-D). Significant deposition of silica nanoparticles on ZnS coated sensor surface was observed in the gypsum supersaturated solution, indicating consequential slime coating of silica fines on sphalerite mineral surface. Substantial deposition of silica nanoparticles on SiO₂ coated surface was also observed suggesting strong homo-aggregation of silica fines in the gypsum supersaturated solution. The interaction behaviour between silica–sphalerite and silica–silica is mainly attributed to the high calcium concentration of the gypsum supersaturated solution. Similar deposition behaviour of silica nanoparticles onto ZnS or SiO₂ coated sensor surface was observed in 800 ppm calcium solution, which is similar to the calcium concentration of the gypsum supersaturated solution. Colloidal force measurement between a silica particle and a fractured sphalerite surface or a silica wafer surface by an atomic force microscopy (AFM) revealed attractive van der Waals force between the mineral particles in both gypsum supersaturated solution and 800 ppm calcium solution. The high calcium concentration of the gypsum supersaturated solution induced the hetero-aggregation between silica and sphalerite, accounting for the observed decrease in flotation selectivity.     

Selective recovery of valuable metals from partial silicated sphalerite at elevated temperature with sulfuric acid solution

The purpose of this work was to study the feasibility at laboratory-scale of a hydrometallurgical process for the selective recovery of valuable metals from partial silicated sphalerite in an oxygen pressure acid leaching system. The factors influencing dissolution efficiency of the ore were investigated and optimized. Under optimum conditions (i.e., temperature of 433 K, sulfuric acid concentration of 41.2 g/L, leaching time of 2.5 h, liquid/solid ratio of 6 mL/g, and pressure of 1.6 MPa) over 97% Zn was extracted into the leach liquor together with 0.3% SiO₂ and 2.9% Pb. The leaching slurry had good solid–liquid separation characteristics, and the filtration rate could be as high as 716 L/m² h. About 96% oxidation of sulfide sulfur to sulfate was achieved under these conditions. Analysis of the content of elemental sulfur in the leaching residues indicated that the fraction of sulfide sulfur determined as elemental sulfur was about 10% at 393 K, and that it decreased with temperature down to 0.5% at 453 K. Ultimate solid residues, which have been concentrated in silica and lead, can be oriented toward the lead smelter after alkali roasting-water washing pretreatment for metal recovery.     

Influence of high concentration Zn2+ on floatability of sphalerite in acidic system

The influence of high concentration Zn²⁺ on the floatability of sphalerite in an acidic system was investigated via flotation experiments, zeta potential measurements, contact angle measurements, and X-ray photoelectron spectroscopy. The results indicated that Zn²⁺ was adsorbed on the sphalerite surface and a Zn-hydroxyl complex was formed at a pH of 4 and a Zn²⁺ concentration of 4×10⁻² mol/L. The zeta potential increased and the contact angle decreased from 84.80° to 36.48°, strongly inhibiting the floatability of sphalerite. When S²⁻ or Cu²⁺ activator was used alone, sphalerite was not activated after Zn²⁺ was adsorbed, and its contact angle did not change significantly. However, by using a combination of S²⁻ and Cu²⁺ activators, its floatability was realized after Zn²⁺ adsorption. This result was attributed to the removal of the Zn-hydroxyl complex on the surface of sphalerite by S²⁻. After this removal, Cu²⁺ was adsorbed on the sphalerite surface to form a Cu₂S·S⁰ hydrophobic film.     

湘南宝山铜铅锌多金属矿床闪锌矿元素地球化学特征及其对成矿的制约

位于钦杭成矿带和南岭成矿带叠合部位的湘南地区是我国重要的W、Sn、Cu、Pb、Zn、Ag多金属矿集区,宝山Cu、Pb、Zn、Ag多金属矿床是湘南地区代表性的矿床。相比中部矽卡岩型矿体,西部和北部脉状矿体研究程度较低。本文拟通过电子探针(EPMA)和激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)原位微区分析技术,对比研究矽卡岩型矿体和脉状矿体的微量元素赋存状态、成矿环境及矿床成因。分析结果显示,宝山矿区不同类型矿体中的闪锌矿均富含Fe、Mn和In,亏损Ga、Ge、Te和Tl等元素,Fe、Mn、Cd和In等元素主要以类质同象的形式赋存于闪锌矿中;矽卡岩型矿体形成于中—高温度环境,脉状矿体形成于中温环境。综合分析认为,宝山铜铅锌银矿床为形成于中—高温环境下的广义矽卡岩型矿床。值得注意的是,Cd含量达到了伴生工业品位的数百倍,具有很高的综合利用价值。     

磨矿对闪锌矿表面电化学性质及浮选的影响

对闪锌矿在不同磨矿介质、机械力以及捕收剂条件下的电化学行为进行了测试。结果表明, 闪锌矿表面适当氧化有利于闪锌矿浮选; 增大闪锌矿与磨矿介质的机械力, 体系的还原性增强, 同时削弱矿物表面的氧化反应, 对浮选不利。在适当的压力和磨矿时间条件下, 采用瓷磨矿介质能有效提高浮选的回收率, 而采用铁介质, 其浮选回收率低于前者。当pH=5时, 在浮选槽内加入药剂比在磨矿机内加入药剂效果要好。     

锌中浸渣-硫化锌精矿协同浸出锌、铟的研究

本文在硫酸体系下对锌中浸渣-硫化锌锌精矿协同浸出工艺与锌中浸渣直接热酸浸出工艺进行了对比。实验结果表面：添加锌精矿进行协同浸出能够有效提高锌中浸渣中有价金属锌、铟和铁的浸出率。在实验的基础上,对锌中浸渣-锌精矿协同浸出机理进行了探讨,为协同浸出提供了理论依据。     

湿法炼锌浸出渣与锌精矿联合浸出工艺研究

开展湿法炼锌浸出渣和锌精矿联合酸浸试验,利用硫酸浸出湿法炼锌常规浸出渣中以铁酸锌等方式存在的锌,同时采用高铁锌精矿将浸出液中的三价铁离子还原为二价铁离子,实现锌精矿中锌的同步浸出。探讨锌浸出渣和锌精矿投料比、初始硫酸浓度、反应时间、液固体积质量比和浸出温度对锌及伴生金属铜、铟和杂质金属铁浸出率的影响。结果表明,在浸出终点浸出液中硫酸浓度20～40g/L、锌浸出渣与锌精矿质量比1∶0.25、原料粒度-0.074mm、液固体积质量比6mL/g、反应温度90℃、反应时间3h的条件下,锌、铟、铜的浸出率都在96%以上,浸出液中95%以上的铁被还原为二价铁离子,满足后续工艺的要求。