石煤钒矿硫酸活化常压浸出提钒工艺

研究石煤钒矿的硫酸活化提钒方法。分别考察矿石粒度、硫酸浓度、活化剂用量、催化剂用量、反应温度、反应时间和浸出液固比等因素对钒浸出率的影响。结果表明:石煤提钒的优化条件为矿石粒度小于74μm的占80%、硫酸浓度150 g/L、活化剂CaF2用量(相对于矿石)60 kg/t、催化剂R用量20 g/L、反应温度90℃、反应时间6 h、液固比(体积/质量,mL/g)2:1,在此优化条件下,钒浸出率可达94%以上;在优化条件下,采用两段逆流浸出,可有效减少活化剂CaF2以及浸出剂硫酸的消耗量;经过两段逆流浸出萃取反萃氧化水解工艺,全流程钒资源总回收率可达86.9%;V2O5产品纯度高于99.5%。     

碳含量对盐助燃烧合成法制备的超细WC粉体形貌、尺寸和相的影响

在WO3-Mg-C-Na2CO3体系中,引入NaCl做稀释剂,通过盐助燃烧合成法制备了超细碳化钨（WC）粉体。利用扫描电镜（SEM）、能谱仪（EDS）和X射线衍射（XRD）对产物进行分析,研究了碳（C）含量对制备的WC粉体的形貌、尺寸和相的影响。结果表明：在m=0.125（Na2CO3的摩尔数）基础上,将原料中碳的摩尔数从l=2增加到2.25和2.5,浸出前产物由少量大尺寸颗粒及大量小尺寸颗粒组成;浸出后产物是由亚微米小颗粒团聚而成,颗粒之间熔化烧结现象很弱,呈弱团聚状态;浸出产物的粒度分布基本符合正态分布,尺寸在200～350nm的范围内;在l=2.25条件下,合成的产物主要为目标产物WC,副产物W2C含量极少。即k=2.0（NaCl的摩尔数）,m=0.125,l=2.25为制备单相WC的工艺条件。     

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 indium dissolution from marmatite with high indium content in pressure acid leaching

The kinetics of oxygen pressure acid leaching marmatite with high indium content was studied. The effects of particle size, agitation rate, temperature, H_2SO_4 concentration, and oxygen partial pressure on leaching rate of indium were investigated. The results show that when the agitation rate is above 600 r-min~(-1), its influence on indium leaching rate is insignificant. It is determined that the leaching rates increase with the increase in sulfuric acid concentration, temperature, partial oxygen pressure, and the decrease in particle size. Moreover, the results demonstrate that the process of indium leaching is controlled by interface chemical reaction, with apparent activation energy of 65.7 k J-mol~(-1). The apparent reaction orders of sulfuric acid and oxygen partial pressure are determined to be 0.749 and 1.260, respectively. The leaching reaction process follows shrinking unreacted core model. And finally, the kinetics model equation is established for indium.     

Kinetics of acid-oxygen leaching of low-sulfur Ni-Cu matte at atmospheric pressure

The leaching of low-sulfur Ni-Cu matte in acid-oxygen (CuSO4-H2SO4-O2) solution at atmospheric pressure was researched. This matte was obtained from high grade Ni-Cu matte by magnetic separation, which mainly contained Ni-Cu alloy and a small quantity of sulfides. The effects of temperature, agitation speed, oxygen flow rate, particle size, acid concentration and concentration of copper ion were studied. It is found that the matte particles are leached by shrinking core mechanism and the leaching process is electrochemically controlled. In a temperature range of 30-60 ℃, the surface reaction is rate-limiting step, with an apparent activation energy of 41.9 kJ/mol. But at higher temperature (70-85℃), the rate process is controlled by diffusion through the product layer, with an apparent activation energy of 7.3 kJ/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...     

STUDY OF PREPARATION PROCESS OF TUNGSTEN POWDER BY SHS WITH A MAGNESIUM THERMIT STAGE

Tungsten powder was fabricated from the system CaWOrMg by self-propagating high-temperature synthesis (SHS) with a magnesium thermit stage. The physic-chemical change during heating and the effects of pressure of sample and diluents (W powder) on product have been studied. The experimental results show that the porosity of combustion product and the particle size of final tungsten powder decrease with increasing pressure of sample. Addition of diluents could increase the particle size of final tungsten powder. The purity of tungsten is improved by leaching in NaOH solution. The results of spectral analysis and particle size distribution of final tungsten powder show that the final Tungsten powder has a median diameter of 0.87μm, specific surface area of 1.09m^2/g and purity of above 99.0%.     

Kinetic study on pressure leaching of high iron sphalerite concentrate

The kinetics of pressure leaching high iron sphalerite concentrate was studied.The effects of agitation rate,temperature, oxygen partial pressure,initial acid concentration,particle size,iron content in the concentrate and concentration of Fe2 added into the solution on the leaching rate of zinc were examined.The experiment results indicate that if the agitation rate is greater than 600 r/min,its influence on Zn leaching rate is not substantial.A suitable rise in temperature can facilitate the leaching reaction,and the temperature should be controlled at 140-150℃.The increase trend of Zn leaching rate becomes slow when pressure is greater than 1.2 MPa,so the pressure is controlled at 1.2-1.4 MPa.Under the conditions of this study,Zn leaching rate decreases with a rise in the initial sulfuric acid concentration;and Zn leaching rate increases with a rise of iron content in the concentrate and Fe 2 concentration in the solution.Moreover,the experiment demonstrates that the leaching process follows the surface chemical reaction control kinetic law of“shrinking of unreacted core”.The activation energy for pressure leaching high iron sphalerite concentrate is calculated,and a mathematical model for this pressure leaching is obtained.The model is promising to guide the practical operation of pressure leaching high iron sphalerite concentrate.     

Parameters affecting reaction rate and conversion of TiO2 chlorination in a fluidized bed reactor: Experimental and modeling approach

Pilot scale chlorination of TiO₂ was carried out with CO as reducing agent. The experimental analysis and modeling of chlorination process of TiO₂ in the presence of CO and Cl₂ in a semi-continuous fluidized bed reactor were aimed. Chlorination process was continuously monitored by measuring the amount of produced TiCl₄ with time. The effects of different operating parameters including chlorination temperature, feedstock particle size and size distribution, amount of feedstock and Cl₂ and CO flow rates on the conversion were systematically investigated. A gradual increase in chlorination temperature led to monotonous increase of conversion rate. Conversion decreased with increased particle size of feedstock. An increase in loaded feedstock led to a decrease in reaction conversion. A model was proposed to predict conversion, particle size distribution and mole fraction of components in gas phase as reaction proceeds. A good agreement between conversions predicted by the model and experimental data under various operating conditions was observed.     

Leaching kinetics of antimony-bearing complex sulfides ore in hydrochloric acid solution with ozone

The leaching kinetics of Sb and Fe from antimony-bearing complex sulfides ore was investigated in HCl solution by oxidation–leaching with ozone. The effects of temperature, HCl concentration, stirring speed and particle size on the process were explored. It is found that the recoveries of Sb and Fe reach 86.1% and 28.8%, respectively, when the reaction conditions are 4.0 mol/L HCl, 900 r/min stirring speed at 85 °C with <0.074 mm particle size after 50 min leaching. XRD analysis indicates that no new solid product forms in the leaching residue and the leaching process can be described by shrinking core model. The leaching of Sb corresponds to diffusion-controlled model at low temperature (15–45 °C) and mixed-controlled model at high temperature (45–85 °C), and the apparent activation energies are 6.91 and 17.93 kJ/mol, respectively. The leaching of Fe corresponds to diffusion-controlled model, and the apparent activation energy is 1.99 kJ/mol. Three semi-empirical rate equations are obtained to describe the leaching process.     

从钯银合金废料中回收钯的实验研究

以钯银合金废料为原料,采用硝酸溶解-盐酸沉银-二氯二氨络亚钯法提纯-水合肼还原工艺回收钯。结果表明,当浓盐酸用量为2 m L/200 m L混合酸液,反应时间1 h时,银沉淀率为99.98%;当氨络合和盐酸酸化沉淀过程溶液最佳p H分别为8和1.5,并经温水洗涤3次,二氯二氨络亚钯纯度达到99.99%以上;该工艺钯回收率大于90%,并制得纯度大于99.99%的海绵钯,其平均粒径不大于0.5μm。     

化学法浸出废旧铝电解槽内衬回收冰晶石和碳粉(英文)

采用两步浸出法对铝电解槽废旧阴极炭块进行处理,以分离出冰晶石并提纯炭粉。研究不同温度、浸出时间和液固比对浸出率的影响。结果表明,在NaOH浸出阶段,可溶性化合物Na3AlF6和Al2O3溶解于NaOH溶液中,浸出率达到65.0%,所得炭粉纯度为72.7%;第二步采用HCl浸出得到炭粉,可溶性化合物CaF2和NaAl11O17溶解到盐酸溶液中,浸出率达到96.2%,炭粉纯度达到96.4%。将上述碱浸和酸浸得到的浸出液进行混合以析出冰晶石,在pH=9、温度为70°C下沉积2h,其析出率达到95.6%,所得冰晶石纯度为96.4%。     

水钴矿中选择性提取铜和钴的新工艺

针对某水钴矿的特点,采取还原酸浸旋流电积新工艺选择性提取其中的铜和钴。系统考察初始硫酸浓度、温度、时间、Na2SO3用量、液固比等因素的影响,确定浸出最佳条件如下:初始硫酸浓度为75g/L,Na2SO3用量为7%,液固比L/S=4 mg/L,温度为70℃,时间为0.5 h。对浸出液进行了旋流电积提取铜和钴的探索实验研究,得到纯度分别为99.95%、99.97%的电积铜、钴产品,铜、钴的直收率分别达到98.23%和94.54%。     

Recovery prediction of copper oxide ore column leaching by hybrid neural genetic algorithm

The artificial neural network (ANN) and hybrid of artificial neural network and genetic algorithm (GANN) were applied to predict the optimized conditions of column leaching of copper oxide ore with relations of input and output data. The leaching experiments were performed in three columns with the heights of 2, 4 and 6 m and in particle size of <25.4 and <50.8 mm. The effects of different operating parameters such as column height, particle size, acid flow rate and leaching time were studied to optimize the conditions to achieve the maximum recovery of copper using column leaching in pilot scale. It was found that the recovery increased with increasing the acid flow rate and leaching time and decreasing particle size and column height. The efficiency of GANN and ANN algorithms was compared with each other. The results showed that GANN is more efficient than ANN in predicting copper recovery. The proposed model can be used to predict the Cu recovery with a reasonable error.     

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。     

从环氧乙烷用失效催化剂中回收银

采用流态化浸出技术研究了从环氧乙烷用失效银催化剂中银的工艺。考察了流化状态、硝酸用量、反应时间等参数对银浸出效果的影响,得到了最佳工艺条件。采用自制流化态溶解装置,使废催化剂处于流动翻滚状态,硝酸用量为理论用量的1.2倍,反应时间不低于1 h,银的浸出率可达到99.88%。浸出液氯化沉淀后采用传统方法精炼提纯,得到99.95%纯度的银。     

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。     

Preparation and characterization of amorphous boron powder with high activity

The amorphous boron powders with high activity were prepared by the high-energy ball milling–combustion synthesis method. The effects of the milling rate and milling time on the crystallinity, microscopic morphology and reactivity of amorphous boron powder were studied. The results show that the crystallinity of amorphous nano-boron powder is only 22.5%, and its purity reaches 92.86%. The high-energy ball milling can significantly refine boron powder particle sizes, whose average particle sizes are smaller than 50 nm, and specific surface areas are of up to 70.03 m²/g. When the transmission electron beam irradiates the samples, they rapidly melt. It can be seen that the monomer amorphous boron size is less than 30 nm from the specimen melting traces, which indicates that the samples have high reactivity.     

Bio-oxidation of arsenopyrite

Oxidation of arsenopyrite with Acidithiobacillus ferrooxidans was studied. The electrochemical results show that arsenopyrite is firstly oxidized to As2S2 at the potential of 0.2-0.3 V （vs SHE） and As2S2 covers the electrode and retards the process continuously. While at higher potential over 0.3 V （vs SHE）, AszS2 is oxidized to H3AsO3, and H3AsO3 is then oxidized to H3AsO4 at 0.8 V （vs SHE）. The leaching results show that the addition of FeS2 can promote the oxidation of As^3＋ to As^5＋ and increase the activity of the bacteria. The best bio-oxidation technical parameters are the initial pH of 1.8-2.0, particle sizes less than 0.074 mm, temperature in the range of 25-30℃ and rotating speed of the orbital incubator of 100-160 r/min. The results provide theoretical and technological supports of bio-oxidation arsenopyrite for pretreating refractory arsenic gold ores.     

Characterization and kinetic study on ammonia leaching of complex copper ore

Ammonia leaching kinetics of a complex Cu-ore assaying 8.8% Cu and 36.1% Fe was examined. Mineralogical characterization indicated that the major phase of the ore was siderite with chalcopyrite as the major sulfide mineral. The effects of parameters such as agitation, temperature, NH₃ concentration, particle size and oxygen partial pressure (p_O2) were investigated. Under the standard leaching conditions of 125–212 µm particle size, 120 °C, 1.29 mol/L NH₃ and 202 kPa of p_O2, about 83% Cu could be selectively extracted in 2.5 h. However, when using higher NH₃ concentration and lower particle size, more than 95% extraction was achieved. The leaching process was found to be surface reaction controlling. The estimated activation energy was (37.6±1.9) kJ/mol and empirical orders of reaction with respect to p_O2 and [NH₃] were about 0.2 and 1, respectively.