Pressure leaching of zinc silicate ore in sulfuric acid medium

Zinc silicate ore was characterized mineralogically and the results showed that zinc exists mainly as hemimorphite and smithsonite in the sample. Sulfuric acid pressure leaching of zinc silicate ore was carried out to assess the effect of particle size, sulfuric acid concentration, pressure, reaction time and temperature on the extraction of zinc and the dissolution of silica. Under the optimum conditions employed, up to 99.25% of zinc extraction and 0.20% silica dissolution are obtained. The main minerals in leaching residue are quartz and small amounts of undissolved oxide minerals of iron, lead and aluminum are associated with quartz.     

高压酸浸镍钼矿提取钼和镍

研究一项针对镍钼矿用高压酸浸的方法回收镍和钼的全湿法工艺。采用该工艺避免了传统上艺焙烧镍钼矿（15％～25％s）带来的人量S02和As2O3排放,减小了对环境的污染;与现有的湿法碱浸回收钼工艺相比,本工艺存酸浸过程中回收了儿乎全部的镍和人部分的钼。在氧压环境下,几乎全部的镍和大部分的钼都进入溶液,少部分的钼留在酸浸渣中,睃浸渣进一步用碱（NaOH）浸出。在最佳的实验条件下,97％的镍和96％的钼分别被浸出。     

以废茶叶为还原剂在硫酸溶液中还原浸出氧化锰矿（英文）

采用废茶叶在硫酸溶液中还原浸出加蓬和湘西氧化锰矿石,探索废茶叶用量、硫酸浓度、固液比、浸出温度和反应时间对浸出过程的影响。对加蓬氧化锰矿,优化的浸出条件为:氧化锰矿与废茶叶的质量比10:4、硫酸浓度2.5 mol/L、固液比7.5:1、浸出温度368 K、浸出时间8 h;在此条件下,加蓬氧化锰矿的浸出率几乎达100%。对于湘西氧化锰矿,优化浸出条件为:氧化锰矿与废茶叶的质量比10:1、硫酸浓度1.7 mol/L、液固比7.5:1、温度368 K、浸出时间8 h;在此条件下,锰的浸出率达到99.8%。氧化锰矿的还原浸出过程符合内扩散控制模型,加蓬和湘西氧化锰矿石的还原浸出反应表观活化能分别为38.2 kJ/mol和20.4 kJ/mol。采用X-射线衍射(XRD)和扫描电子显微镜(SEM)对浸出前、后的锰渣进行表征。     

Recovery of valuable metals from zinc leaching residue by sulfate roasting and water leaching

Zinc leaching residue (ZLR), produced from traditional zinc hydrometallurgy process, is not only a hazardous waste but also a potential valuable solid. The combination of sulfate roasting and water leaching was employed to recover the valuable metals from ZLR. The ZLR was initially roasted with ferric sulfate at 640 °C for 1 h with ferric sulfate/zinc ferrite mole ratio of 1.2. In this process, the valuable metals were efficiently transformed into water soluble sulfate, while iron remains as ferric oxide. Thereafter, water leaching was conducted to extract the valuable metals sulfate for recovery. The recovery rates of zinc, manganese, copper, cadmium and iron were 92.4%, 93.3%, 99.3%, 91.4% and 1.1%, respectively. A leaching toxicity test for ZLR was performed after water leaching. The results indicated that the final residue was effectively detoxified and all of the heavy metal leaching concentrations were under the allowable limit.     

锰铁合金渣浸出液制备电子级硫酸锰(英文)

以锰铁合金渣为原料,经研磨、硫酸浸出后,采用中和-水解、氟化沉淀、硫化沉淀和重结晶法去除浸出液中的铁、铝、钙、镁和重金属以及钠、钾等离子以制备电子级硫酸锰。研究反应pH、反应温度和不同添加剂的用量对硫酸锰产品中杂质含量的影响,并得到了较优的温度、pH、沉淀剂的用量等工艺条件。结果表明:在较优工艺条件下,所制备的碳酸锰中,Ca2+、Mg2+、Na+、K+杂质离子的含量小于0.005%,Fe3+、Al3+和重金属离子的含量小于0.001%,Mn2+的含量大于32%,硫酸锰产品的质量满足锂离子电池正极材料的要求。     

焙烧氟碳铈矿硫酸浸出稀土的动力学(英文)

研究了硫酸浸出德昌稀土与天青石共伴生矿的焙烧矿过程。考查粒度、搅拌速度、硫酸浓度和温度对稀土浸出率的影响,并对稀土的浸出动力学进行分析。在选定的浸出条件下:粒径0.074～0.100mm、硫酸浓度1.5mol/L、液固比8:1、搅拌速度500r/min,稀土浸出反应受内扩散控制,表观活化能为9.977kJ/mol。     

Technological mineralogy and environmental activity of zinc leaching residue from zinc hydrometallurgical process

Chemical, physical, structural and morphological properties of zinc leaching residue were examined by the combination of various detection means such as AAS, XRF, XRD, Mössbauer spectrometry, SEM-EDS, TG-DSC, XPS and FTIR. The toxicity characteristic leaching procedure (TCLP) was used to investigate the environmental activity of zinc leaching residue for a short contact time. The phase composition analysis indicated that the zinc leaching residue mainly consists of super refined flocculent particles including zinc ferrite, sulfate and silicate. The physical structural analysis showed that it has a thermal instability and strong water absorption properties. The results of TCLP indicated that the amounts of Zn and Cd in the leaching solution exceed 40 and 90 times of limit, respectively, which demonstrate that this residue is unstable in weak acidic environment for a short contact time.     

高炉尘泥化学除锌

为了降低经物理分选后的高炉精泥中锌的含量,对高炉精泥进行化学浸出除锌研究,考察浸出剂、浸出时间、温度、液固比和搅拌速度等对浸出的影响,并进行理论分析。结果表明：硫酸对锌的浸出率最高,氯化铁次之,氨水最低;在合适的浸出条件下：液固比8-1,温度20℃,硫酸浓度125 g/L,浸出时间35 min和搅拌速度150 r/min,锌浸出率为73.9%,高炉精泥中的锌含量从1.46%降低到0.38%。对硫酸浸出脱锌的动力学和反应机制的研究表明,浸出过程遵从1-2α/3-（1-α）2/3=kt,浸出反应的活化能为8.89 kJ/mol,属于扩散控制过程。     

锌浸渣还原焙烧-磁选回收铁

在查明锌浸渣工艺矿物学的基础上,采用还原焙烧将铁酸锌分解为氧化锌和磁性氧化铁,再通过磁选的方法回收铁,达到锌、铁分离的目的。实验考查了焙烧温度、焙烧时间、还原剂用量对铁酸锌分解率、铁回收率和铁品位的影响。结果表明:在焙烧温度为950℃、焙烧时间为1 h及还原剂添加量为10%和5%的条件下,铁酸锌分解率达到72.05%,铁回收率可达到91.79%,精矿中铁的品位为50%左右。焙烧及磁选过程中颗粒的团聚包裹是铁精矿品位不高的主要原因。     

Transformation and leaching kinetics of silicon from low-grade nickel laterite ore by pre-roasting and alkaline leaching process

The mineralogical phase transformation of a low-grade nickel laterite ore during pre-roasting process and the extraction of silicon during alkaline leaching process were investigated. The results indicate that the reaction activity of nickel ores is effectively improved by pre-roasting at 650 °C for 2 h, because of the transformation of lizardite into magnesium olivine and protoenstatite. When finely ground ore samples (44–61 μm) pre-roasted firstly react with sodium hydroxide solution (60 g/L) with a solid/liquid ratio of 1:5 at 140 °C for 120 min, the extraction of silicon can reach 89.89%, and the other valuable elements of magnesium, iron and nickel are accumulated in the solid residues. The leaching kinetics of nickel laterite ore can be described successfully by the diffusion through the product layer control model. The activation energy is calculated to be 11.63 kJ/mol and the kinetics equation can be expressed as 1–3(1–x)^2/3+2(1–x)=13.53×10^?2exp[–11.63/(RT)]t.     

镍红土矿高压酸浸过程的金属元素浸出行为

以镍、钴的提取为目的,研究褐铁矿型镍红土矿高压酸浸过程中各金属元素的浸出行为,探讨硫酸加入量、浸出温度、浸出时间及液固比对各金属元素浸出率的影响.实验结果表明,在优化条件下Ni、Co、Mn和Mg的浸出率分别达到97%、96%、93%和95%以上,则Fe的浸出率小于1%.对高压浸出渣的分析表明,渣中的铁和硫主要分别以赤铁...     

Increasing silver leaching rate from leaching-resistant zinc residues by thiourea leaching method with pressurized preoxidation process

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Co-intensification of cyanide leaching gold by mercury ions and oxidant

The effects of mercury ions on gold cyanidation were studied. The results show that under low cyanide concentration, gold cyanide process is controlled by CN^? transfer, while at higher cyanide concentration, there forms passivation on gold surface. Therefore, chemical oxidation of gold in cyanide solution of higher concentration is controlled by surface reaction. Small quantity of additions of mercury ions bring about great increases in anodic gold dissolution rate, decreases the passivation and reduces the equilibrium activated energy. In addition, they also markedly change the effect pattern of cyanide concentration. Mercury ions show positive effects on cathodic reduction of oxygen and raise the rate of electrochemical step of the cathodic reduction of oxygen. Addition of a certain amount of hydrogen peroxide is confirmed to be an effective way for intensification of cathodic process on gold electrode. Active potential range and current peak on anodic dissolution are enlarged when being co-intensified with Hg²⁺ and hydrogen peroxide. Co-intensifying effect may be obtained and gold leaching rate is considerably increased on cyanide leaching of gold from gold concentrates.     

Kinetics of simultaneous leaching of Ag and Pb from hydrometallurgical zinc residues by chloride

The leaching kinetics of silver and lead simultaneously from zinc residue by chloride was investigated.The effects of stirring speed,temperature,sodium chloride concentration,particle size and liquid/solid ratio on Ag and Pb dissolution in sodium chloride were studied.It was determined that the dissolution rates increased with increasing sodium chloride concentration,temperature and decreasing particle size.The dissolution kinetics followed a shrinking core model,with inter-diffusion through gangue layer as the rate determining step.This finding is in accordance with the apparent activation energy(Ea)of 26.8 kJ.mol-1(Ag)and 26.5 kJ.mo1-1(Pb),and a linear relationship between the rate constant and the reciprocal of squared particle size.The orders of reaction with respect to sodium chloride concentration,temperature and particle size were also achieved.The rate of reaction based on diffusion-controlled process can be expressed by semi-empirical equations.     

从镍钼矿中提取镍钼的工艺

针对现行镍钼矿处理工艺存在的钼镍需要分别提取的缺陷,提出镍钼矿加钙氧化焙烧-低温硫酸化焙烧-水浸提取镍钼的新工艺。以贵州遵义镍钼矿为原料,对CaO加入量、氧化焙烧温度、氧化焙烧时间、硫酸加入量、硫酸化焙烧温度、硫酸化焙烧时间以及焙砂水浸工艺参数对镍钼浸出率的影响进行研究。结果表明:在最佳工艺条件下,钼的浸出率为97.33%,镍的浸出率为93.16%,且最佳工艺参数为100 g镍钼矿加入35 g CaO,700℃氧化焙烧2 h,得到的焙砂加入70 mL浓硫酸,再经250℃硫酸化焙烧2 h;硫酸化焙烧得到的焙砂按液固比2:1加水搅拌,经98℃浸出2 h。加入CaO不仅能有效减少镍钼矿氧化焙烧烟气对环境造成的污染,而且能显著提高镍的浸出率。     

氧化锌贫矿提锌渣中铅和银的氯盐一步浸出

运用X射线衍射、扫描电镜和X射线能谱等分析手段,对山东某地深度氧化锌贫矿提锌后渣进行工艺矿物学特征分析可知,矿物中金属赋存状态复杂,属难选矿物。开发出氯盐一步法浸出铅和银的新工艺,考察反应温度、NaCl浓度、添加剂用量、液固比、HCl加入量和浸出时间对浸出过程的影响。结果表明:加入添加剂对铅的浸出率没有影响,但可以显著提高银的浸出率。条件试验研究得出最佳工艺条件如下:浸出温度90℃、NaCl浓度390 g/L、添加剂用量15 mL、液固比(质量比)7?1、HCl加入量3 mL、浸出时间3 h。在此最佳工艺条件下,铅的浸出率达到95%左右,银的浸出率达到90%左右。     

铁酸锌选择性还原及其在锌浸出渣处理中的应用

传统湿法炼锌过程产生大量富含有价金属资源的铁酸锌废渣,铁的分离是实现铁酸锌废渣中有价金属资源回收的关键。提出含大量铁酸锌的锌浸出渣选择性还原焙烧?浸出分离铁和锌的新方法。通过热力学分析确定铁酸锌分解过程中Fe3O4和ZnO产物的优势区域,并发现V(CO)/V(CO+CO2)比是控制铁酸锌还原焙烧产物物相的关键因素,在V(CO)/V(CO+CO2)比在2.68%?36.18%范围内,铁酸锌优先分解生成在Fe3O4和ZnO。通过TG分析,确定铁酸锌还原焙烧的最佳条件为焙烧温度700?750°C,CO体积分数6%,V(CO)/V(CO+CO2)30%。基于上述研究结果,对富含铁酸锌的锌浸渣进行还原焙烧处理,焙烧产物经酸浸后,锌的浸出率达70%,铁的浸出率仅为18.4%,实现锌浸渣中锌和铁的有效分离。     

还原酸浸法从低品位水钴矿中提取铜和钴

以Na2SO3为还原剂从水钴矿还原酸浸液中提取铜和钴,研究了还原剂种类及用量、浸出温度、硫酸浓度等因素对水钴矿还原酸浸过程中有价金属铜和钴浸出率的影响。结果表明,Na2SO3是较适宜的还原剂;在还原剂用量为水钴矿原矿质量的10%、硫酸浓度为3 mol/L、浸出温度为60℃、液固比为2-1、浸出时间为60 min的条件下,铜和钴的浸出率分别达99.06%和98.87%。并提出了"M5640萃铜→黄钠铁矾法除铁→碳酸钠除铝→氟化钠除钙、镁→蒸发结晶得钴产品"的后续分离净化流程,能有望应用于水钴矿及类似物料中有价金属的提取与分离的工业生产。