Na_2SO_3从硒碲富集物中浸出硒动力学(英文)

研究用Na2SO3溶液从硒碲富集物中浸出硒的动力学。该硒碲富集物的微观形貌主要为球状体和柱状体,其粒径范围为17.77～56.58μm,且其主要成分为41.73%Se和40.96%Te。研究Na2SO3浓度(126～315 g/L)、搅拌速度(100～400 r/min)、反应温度(23～95°C)、液固比(7:1～14:1)及硒碲富集物平均粒径(17.77～56.58μm)对Se浸出率的影响。结果表明:增加Na2SO3浓度、提高搅拌速度、升高反应温度和增加液固比均可以提高Se浸出率,而增大硒碲富集物的粒径会导致Se的浸出率降低;反应温度对Se浸出率影响较大,当反应温度从23°C升高至95°C时,Se浸出率从21%增至67%;该浸出过程符合Avrami模型,其模型特征参数和表观活化能分别为0.235和20.847kJ/mol。     

Na2SO3浸出法提纯粗硒工艺研究

采用Na2SO3浸出法提纯粗硒,研究浸硒过程Na2SO3溶液浓度、浸出温度、浸出时间、搅拌速度和净化过程Na2S溶液浓度对提纯粗硒的影响,采用XRD、SEM对所得样品进行表征.结果表明,Na2SO3溶液浓度为300 g/L、浸出温度为98℃、浸出时间为2 h,搅拌速度为150 r/min、Na2S溶液浓度为2 g/L时...     

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%。     

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。     

盐酸溶液中双氧水浸出黄铜矿（英文）

本文旨在研究以双氧水为强氧化剂的黄铜矿精矿的盐酸浸出过程。研究搅拌速度、固液比、温度、HCl和H_2O_2浓度等浸出参数对金属浸出率的影响。室温下,用3.0 mol/L H_2O_2和0.5 mol/L HCl溶液与黄铜矿反应180 min后,获得33%的最大铜浸出率。结果表明,在反应的前60 min,铜的浸出率增大;此后,由于双氧水的快速催化分解,铜浸出率基本上保持不变。此外,固液比对铜的浸出率影响显著,而且在最稀的悬浮液中(即固液比1:100)铜的浸出率最高。溶出过程可用一级动力学方程描述,表观活化能为19.6 kJ/mol,表明溶出过程受扩散控制,对于HCl和H_2O_2的反应级数分别为0.30和0.53。浸出渣的XRD和SEM/EDS分析结果表明,矿物表面生成单质硫,抑制浸出率的提高。     

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。     

煤粉炉高铝粉煤灰碱溶脱硅反应动力学

以内蒙古中西部地区某电厂煤粉炉高铝粉煤灰为对象,研究NaOH溶液脱除粉煤灰非晶态SiO2过程中搅拌速度、反应温度、NaOH溶液初始浓度对粉煤灰非晶态SiO2浸出率的影响,通过实验数据与液固多相反应缩芯模型拟合的方法确定动力学规律及动力学方程。结果表明:SiO2的浸出过程分为2个阶段,反应前期为表面反应控制,表观活化能为80.15 kJ/mol;反应后期为固膜扩散控制,表观活化能为29.93 kJ/mol。结合动力学实验结果及扫描电镜(SEM)、能谱(EDS)分析可知,随着反应的进行,固相产物逐渐附着于粉煤灰表面形成固膜导致控制步骤转变。     

混合铜渣的微波浸出（英文）

在微波炉中采用双氧水和乙酸溶液浸出由转炉和闪速炉渣组成的混合铜渣。该混合铜渣含51%Fe_2O_3、3.8%CuO、3.2%Zn。研究表明,对混合渣浸出率影响较大的因素有:浸出时间,液固比,双氧水浓度和乙酸浓度。在最优的浸出条件下:乙酸浓度4 mol/L,双氧水浓度4 mol/L,微波功率900 W,浸出时间30 min,液固比25 mg/L,浸出温度100°C,铜、铁、锌的浸出率分别可达到95%、1.6%和30%。与传统的浸出工艺相比较,微波浸出可缩短浸出时间,同时,可选择性浸出渣中的金属元素。动力学研究表明,渣中金属元素的浸出可用一收缩未反应核模型来描述,浸出反应的表观活化能为16.64 kJ/mol,反应级数为1.09.     

包头稀土精矿的配合浸出及动力学

采用氯化铝盐酸体系配合浸出包头混合稀土精矿,并对浸出过程动力学进行研究,浸出过程主要考察盐酸和氯化铝的浓度、液固比、搅拌速度、温度及反应时间对精矿浸出的影响。结果表明,随着盐酸和氯化铝的浓度和液固比的增大、反应时间的延长和反应温度的升高,精矿的浸出率逐渐增大,得到的优化浸出工艺条件如下:HCl和AlCl3浓度分别为4.0 mol/L和1.5 mol/L,液固比为20 mL/g,搅拌速度为300 r/min,温度为85℃,时间为90 min。SEM-EDS及动力学分析结果表明,精矿浸出过程符合一种受固体颗粒表面的界面交换和固膜扩散混合控制的新缩小核模型,表观活化能为35.3 kJ/mol,阿伦尼乌斯常数k0=419.95,反应级数a,b和c分别为1.265,1.208和1.22,通过计算推导出反应动力学方程。     

NaCl-HCl体系浸出铅渣中铅的动力学分析

以浸出温度、NaCl浓度、颗粒粒度和液固比对铅浸出率影响的实验条件和数据为基础,建立NaCl-HCl体系,采用液-固多相反应的收缩核模型,系统分析了铅渣中铅的浸出动力学过程。结果表明:根据实验数据求出浸出反应的宏观动力学方程,计算得到表观活化能为45.239 k J/mol,说明该体系浸出过程受表面化学反应控制;在实验选取的参数范围内,增大NaCl浓度、浸出温度和液固比以及减小颗粒粒度均有利于提高铅的浸出率。     

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.     

湿法炼锌净化渣酸浸的动力学

对湿法炼锌净化渣的浸出动力学进行了研究,并探讨了硫酸浓度、反应温度、粒度等对钴、锌浸出率的影响规律。从动力学的角度分析了整个浸出过程,得到优化条件：液固比50：1(mL/g),硫酸浓度100 g/L,反应温度70°C,粒度75~80μm,反应时间20 min。在此优化条件下钴的浸出率为99.8%,锌的浸出率为91.97%。结果表明：在硫酸体系中钴的浸出符合不生成固体产物层的“未反应收缩核”模型。通过 Arrhenius 经验公式求得钴和锌表观反应活化能分别为11.693 kJ/mol和6.6894 kJ/mol,这表明浸出过程受边界层扩散控制。     

Optimization of operating parameters and kinetics for chloride leaching of lead from melting furnace slag

The feasibility and kinetics of lead recovery from the slag of traditional lead melting furnace using chloride leaching were investigated. The effects of operating parameters such as leaching time, NaCl concentration, FeCl₃ concentration, liquid/solid ratio, stirring rate, temperature, and particle size on recovery of lead were studied and the optimization was done through the response surface methodology (RSM) based on central composite design (CCD) model. The optimum conditions were achieved as follows: leaching time 60 min, 80 °C, stirring rate 800 r/min, NaCl concentration 200 g/L, FeCl₃ concentration 80 g/L, liquid/solid ratio 16, and particle size less than 106 μm. More than 96% of lead was effectively recovered in optimum condition. Based on analysis of variance, the reaction temperature, liquid/solid ratio, and NaCl concentration were determined as the most effective parameters on leaching process, respectively. Kinetics study revealed that chloride leaching of galena is a first-order reaction and the diffusion through solid reaction product and chemical reaction control the mechanism. The activation energy of chloride leaching of galena was determined using Arrhenius model as 27.9 kJ/mol.     

Coupling leaching of sphalerite concentrate

Coupling process of sphalerite concentrate leaching in H2SO4-HNO3 and tetrachloroethylene extracting of sulfur was investigated. Effects of leaching temperature, leaching time, mass ratio of liquid to solid and tetrachloroethylene addition on zinc leaching processes were examined separately. SEM images of sphalerite concentrate and residues were performed by using JEM-6700F field emission scanning electron microscope. The relationship between the number of recycling and extraction ratio of zinc was studied. The results indicate that 99.6% zinc is obtained after leaching for 3 h at 85℃ and pressure of 0.1MPaO2, with 20g sphalerite concentrate in 200 mL leaching solution containing 2.0mol/L H2SO4 and 0.2mol/L HNO3, in the presence of 10 mL C2Cl4. The leaching time of zinc is 50% shorter than that in the common leaching. The coupling effect is distinct. The recycled C2Cl4 exerts little influence on extraction ratio of zinc.     

Leaching kinetics of selenium from copper anode slimes by nitric acid-sulfuric acid mixture

The leaching kinetics of selenium from copper anode slimes was studied in a nitric acid-sulfuric acid mixture. The effects of main parameters on selenium leaching showed that the leaching rate of selenium was practically independent of stirring speed, while dependent on temperature and the concentrations of HNO₃ and H₂SO₄. The leaching of selenium includes two stages. The activation energy in the first stage is 103.5 kJ/mol, and the chemical reaction is the rate controlling step. It was almost independent of H₂SO₄ concentration and dependent on HNO₃ concentration since the empirical reaction order with respect to HNO₃ concentration is 0.5613. In the second stage, the activation energy is 30.6 kJ/mol, and the process is controlled by a mixture of diffusion and chemical reaction. The leaching of selenium was almost independent of HNO₃ concentration.     

Dissolution kinetics and thermodynamic analysis of vanadium trioxide during pressure oxidation

The dissolution kinetics of vanadium trioxide in sulphuric acid-oxygen medium was examined. It was determined that the concentration of sulphuric acid and stirring speed above 800 r min 1 did not significantly affect vanadium extraction. The dissolution rate increased with increasing temperature and oxygen partial pressure, but decreased with increasing particle size. The dissolution kinetics was controlled by the chemical reaction at the surface with the estimated activation energy of 43.46 kJ·mol-1. The l...     

在H2SO4-HCl-H2O复合体系中氧化浸出镍钼矿冶炼烟尘中的硒

对在H2SO4-HCl-H2O复合体系中氧化浸出镍钼矿冶炼烟尘中的硒进行热力学分析,确定从镍钼矿冶炼烟尘中浸出硒的新工艺及其最优技术参数.采用XRD对镍钼矿冶炼烟尘及其浸出渣进行表征.结果表明:在最佳技术条件下,硒浸出率达到98%,浸出渣含硒0.16%(质量分数);冶炼烟尘中硒以单质形式存在,未见硒及其化合物出现,表明烟尘中的硒浸出较完全;浸出渣主要由SiO2、CaSO4、A12SiO5、As2O3和KAlSi3O8组成.