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。     

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。     

燕麦秸秆还原浸出低品位软锰矿及其动力学

以燕麦秸秆为还原剂,在硫酸介质中直接浸出某低品位软锰矿,研究浸出过程的工艺条件和动力学。结果表明:在硫酸浓度为150 g/L、液固比为9 mL/g、麦秆与软锰矿质量比为0.3、浸出温度90℃、浸出60 min的条件下,锰浸出率可达96.1%,此时,铁浸出率为46.8%,浸出液化学需氧量(COD)值为6.2 g/L。动力学研究表明:锰的浸出过程在333~363 K内符合未反应核缩减模型,浸出过程主要受界面化学反应步骤控制,其浸出表观活化能为69.4 kJ/mol。     

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。     

铟的还原浸出动力学及分步沉淀选择性分离（英文）

开展硫化锌精矿还原浸出高铁锌浸出渣高效浸铟及浸出液中铟选择性分离的研究。结果表明：在固体物料粒度74～105μm、反应温度90℃、浸出时间300 min、硫酸浓度1.4 mol/L的条件下,铟的浸出率达95%以上。采用收缩核模型对还原浸出动力学进行分析,不同条件下的浸出实验结果表明反应受穿过固体产物层的扩散控制,活化能为17.96 k J/mol,相对于硫酸浓度的反应级数为2.41。铁粉置换沉铜过程铜和砷的沉淀率均达99%以上。98%以上的铟从含高亚铁离子浓度的硫酸锌溶液中选择性分离,获得铟含量约为2.4%的富铟渣,经酸浸-萃取-电积工艺流程进一步处理后可得到纯铟。     

含锌尘泥中锌的浸出行为及动力学

采用单因素浸出试验对含锌尘泥中锌的浸出动力学进行研究,并探讨硫酸浓度、液固比、搅拌速度、反应温度等因素对锌浸出率的影响。结果表明:在硫酸浓度为0.5 mol/L,液固比为6:1(mL:g),搅拌速度为300 r/min,反应时间40 min的条件下,锌的最终浸出率达到96.30%;含锌冶金尘泥在硫酸体系中锌的浸出过程符合n=0.16的Avrami动力学模型,浸出反应表观活化能为10 k J/mol,表明整个浸出过程受边界层扩散控制。采用SEM、XRD及EDS表征含锌尘泥原料以及浸出渣的结构和形貌,结果表明绝大部分锌被浸出,而铁、硅、碳等元素则被留在浸出渣中。     

含镉烟灰在酸性介质中的浸出行为及过程优化

对含镉烟灰的物相组成进行了系统分析,并提出针对性的工艺流程。针对硫酸浸出含镉烟灰的过程,采用响应曲面设计方法对操作条件进行了优化,考察了反应温度、液固比、硫酸浓度及其交互作用对Cd、As、Zn浸出率的影响关系,构建了二阶数学模型和三维响应曲面图,确定了Cd、Zn、As的浸出率分别大于92%、95%和50%的优化浸出条件区域,即反应温度25~60℃,液固比6~8 mL/g,硫酸浓度0.3~0.4 mol/L。结果表明:该模型能够准确预测含镉烟灰在硫酸中的浸出效果;在最优区域内,As的浸出率较低,其主要原因是原料中的砷酸锌在低酸条件未分解。     

采用碱浸预脱硅-氰化工艺从氰化尾渣中回收金

采用高浓度碱浸对氰化尾渣进行预脱硅处理,考察搅拌速度、固液比、Na OH浓度及温度对硅浸出速率的影响,研究脱硅过程的反应动力学,得到相应的动力学方程。结果表明:当搅拌速度为400 r/min、固液比为1:5、Na OH浓度为80%、反应温度为280℃时,二氧化硅的浸出率为91.8%;碱浸过程受产物层内扩散控制,表观反应活化能为37.375 k J/mol。通过正交实验对氰化浸金的条件进行了优化,在Si O2浸出率为91.8%,Na CN浓度为1.5 g/L,固液比为1:3,浸出时间为48 h的条件下,金的浸出率为87.83%。     

氨浸出混合铜矿石的表征及动力学(英文)

研究了含8.8%Cu和36.1%Fe的混合铜矿石的氨浸出动力学。矿物学表征表明,该矿石的含铁成分以菱铁矿为主,硫化矿以黄铜矿为主。研究了工艺参数,如搅拌速度、反应温度、氨浓度、矿石粒径、氧分压对氨浸出过程的影响。在标准的浸出条件下,即粒径125~212μm、反应温度120°C、NH3浓度1.29 mol/L、氧分压202 kPa,在2.5 h内Cu的浸出率达到83%。在使用较高浓度的氨和较小粒径的矿石时,Cu的浸出率能够达到95%。动力学研究结果表明,浸出过程为表面反应控制,估算出的活化能为(37.6±1.9)kJ/mol,氧分压与氨浓度的反应级数分别为0.2和1。     

钒钛磁铁矿提钒尾渣浸取钒

采用硫酸氢氟酸次氯酸钠组合浸出体系浸取钒钛磁铁矿提钒尾渣中的钒,研究浸出过程中试剂浓度、浸出液固比、浸出温度、浸出时间、物料粒度对钒浸出率的影响。结果表明:钒的浸出率随试剂浓度、液固比、温度和时间的升高而增大;当矿物粒度小于0.20 mm时,钒浸出率有随矿物粒度变小而减小的趋势。在物料粒度0.15~0.25 mm、初始硫酸浓度150 g/L、初始氢氟酸浓度30 g/L、次氯酸钠加入量为矿量1.5%、矿浆液固比6:1、浸出温度90℃、浸出时间6 h、搅拌速度500 r/min的条件下,钒的浸出率可达85%以上。     

Kinetics of zinc sulfide concentrate direct leaching in pilot plant scale and development of semi-empirical model

The direct leaching kinetics of an iron-poor zinc sulfide concentrate in the tubular reactor was examined. All tests were carried out in the pilot plant. To allow the execution of hydrostatic pressure condition, the slurry with ferrous sulfate and sulfuric acid solution was filled into a vertical tube (9 m in height) and air was blown from the bottom of the reactor. The effects of initial acid concentration, temperature, particle size, initial zinc sulfate concentration, pulp density and the concentration of Fe on the leaching kinetics were investigated. Results of the kinetic analysis indicate that direct leaching of zinc sulfide concentrate follows shrinking core model (SCM). This process was controlled by a chemical reaction with the apparent activation energy of 49.7 kJ/mol. Furthermore, a semi-empirical equation is obtained, showing that the order of the iron, sulfuric acid and zinc sulfate concentrations and particle radius are 0.982, 0.189, ?0.097 and ?0.992, respectively. Analysis of the unreacted and reacted sulfide particles by SEM–EDS shows that insensitive agitation in the reactor causes detachment of the sulfur layer from the particles surface in lower than 60% Zn conversion and lixiviant in the face with sphalerite particles.     

氟碳铈矿盐酸浸出过程的动力学

考察盐酸浓度、浸出温度、液固比和矿物粒度对浸出速度的影响.结果表明:在盐酸浓度6 mol/L、浸出温度90C、液固比15:1、矿物粒度25 μm的条件下浸出90 min后,氟碳铈矿中稀土碳酸盐的浸出率达到89.6％,而稀土氟化物的浸出率仪为1.5％.氟碳铈矿浸出过程符合产物层扩散模型,稀土碳酸盐和氟化物浸出过程的表观活...     

Kinetics of iron removal from metallurgical grade silicon with pressure leaching

In this paper, the kinetics of pressure leaching for purification of metallurgical grade silicon with hydrochloric acid was investigated. The effects of particle size, temperature, total pressure, and concentration of hydrochloric acid on the kinetics and mechanism of iron removal were studied. It was found that the reaction kinetic model followed the shrinking core model, and the apparent activation energy of the leaching reaction was 46.908 kJ/mol. And the apparent reaction order of iron removal with pres...     

Effect of mechanical activation on dissolution kinetics of neutral leach residue of zinc calcine in sulphuric acid

Neutral leach residue of zinc calcine (NLRZC) was mechanically activated by a stirring ball mill. Subsequently, the changes in physicochemical properties and dissolution kinetics in sulphuric acid were studied. The crystalline structure, morphology, particle size and specific surface area of the non-activated and mechanically activated NLRZC were characterized by X-ray diffraction, scanning electron microscope, particle size analyzer and volumetric adsorption analyzer, respectively. The characterization results indicate that mechanical activation (MA) induced remarkable changes in the physicochemical properties of NLRZC. The leaching experiments show that MA significantly enhances the leaching reactivity of NLRZC using the zinc extraction as evaluating index. After NLRZC is mechanically activated for 30 min and 60 min, the activation energy decreases from 56.6 kJ/mol of non-activated NLRZC to 36.1 kJ/mol and 29.9 kJ/mol, respectively. The reaction orders of the non-activated, 30 and 60 min activated NLRZC dissolution with respect to H₂SO₄ concentration were found to be 0.34, 0.30, and 0.29, respectively.     

Reductive acid leaching of valuable metals from spent lithium-ion batteries using hydrazine sulfate as reductant

Hydrazine sulfate was used as a reducing agent for the leaching of Li, Ni, Co and Mn from spent lithium-ion batteries. The effects of the reaction conditions on the leaching mechanism and kinetics were characterized and examined. 97% of the available Li, 96% of the available Ni, 95% of the available Co, and 86% of the available Mn are extracted under the following optimized conditions: sulfuric acid concentration of 2.0 mol/L, hydrazine sulfate dosage of 30 g/L, solid-to-liquid ratio of 50 g/L, temperature of 80 °C, and leaching time of 60 min. The activation energies of the leaching are determined to be 44.32, 59.37 and 55.62 kJ/mol for Li, Ni and Co, respectively. By performing X-ray diffraction and scanning electron microscopy in conjunction with energy dispersive X-ray spectroscopy, it is confirmed that the main phase in the leaching residue is MnO₂. The results show that hydrazine sulfate is an effective reducing agent in the acid leaching process for spent lithium-ion batteries.     

湿法炼锌废渣中硫脲浸出银的动力学

探讨了从湿法炼锌废渣中用硫脲浸出回收银的浸出反应动力学,从这种难浸的含银炼锌废渣中用硫脲浸出回收银,浸出反应是一种典型的氧化还原反应并可充分进行,同时,通过动力学推导得出,从湿法炼锌废渣中用硫脲浸出银的反应动力学模型为收缩核动力学模型,同时计算出浸出活化能为13．26kJ/mol。该模型反映了浸出过程中控制整个反应速率的决定步骤是固膜扩散速率,并较好地说明了浸出机理。     

氯盐浸出硫化银之研究

用电位—log[Cl~-]图分析高铁氯盐体系浸出硫化银的热力学可能性。用试剂硫化银进行的动力学实验考察了粒度、浸出剂初始pH值、氯离子浓度、高铁离子浓度和温度等对银浸出率的影响。结果表明,浸出过程很好地符合“未反应芯”动力学模型,求得的表观活化能为56.24千焦/摩尔,得到动力学方程式为:1-2/3R-(1-R)2/3=1.02×10_(-4)r_0~(-2)[H~+]~(0.36)[Cl~-]~3[Fe(Ⅲ)]exp(-56240/RT)t,过程受固膜扩散控制。