浸矿剂浓度对稀土浸取效果的影响

混合岩离子型稀土矿床在赣南分布广泛,其结构构造及稀土配分与花岗岩存在差异性。就浸取效果对赣南某混合岩型离子型稀土矿的浸取浓度做了柱浸试验,并且对不同浓度浸矿剂所需的浸矿时间及所浸出的母液浓度等浸取效果进行对比分析,以期给该矿山的稀土回收提供技术参考。     

Accelerating leaching of copper ore with surfactant and the analysis of reaction kinetics

To solve the problem of low permeability and lower extraction rates of high-mud ores, a surfactant was added as a penetrant to the pregnant leaching solution during column leaching tests. On the basis of the theories of physical chemistry and seepage flow mechanics, the mechanism by which seepage is enhanced under the effects of the surfactant was analyzed. The results show that the action modes of the surfactant were divided into four aspects: changing the wettability of the ore, reducing the viscosity of the leaching solution, adsorbing onto the surface of ore, and enhancing the permeability effect. The findings of column leaching tests demonstrated that permeability was substantially improved by the surfactant. In the later period of leaching, the permeability coefficient was two times higher than that of the control group. Meanwhile, the ore extraction rate increased by approximately 10%. During the leaching process, the surface tension of the solution did not substantially change, and that of the solution with surfactant increased slightly. The kinetics analysis of ore column leaching illustrated that the leaching processes were controlled by both internal diffusion(principal factor) and chemical reaction.     

Unsaturated flow and solute transport in a porous column using spherical ore particles

This paper dealt with the development of a two-dimensional (2D) mathematical model for column leaching and confirmed the important simulation parameters through experiment. The unsaturated state of the variably saturated flow column and the solute transport of copper ions were studied during leaching. The fluid flow problem was handled using the Richards equation on the premise of an ambient pressure column air, where the van Genuchten formulas were applied to define the nonlinear relationships of pressure head with the retention and permeability properties. The ore column permeability test gave a varied hydraulic conductivity, which was analyzed in the model. In the solute transport problem, the copper ion concentration was solved using the advection-diffusion-reaction equation whose reaction term was determined by the joint analysis of experimental copper leaching rate and the shrinking core model. Particle- and column-scale leaching tests were carried out to illustrate the difference and connection of copper extraction in both processes. This fluid flow and solute transport coupled model was determined through the finite element method using the numerical simulation software, COMSOL Multiphysics.     

不同孔隙比下风化壳淋积型稀土矿强度特性

风化壳淋积型稀土开采过程中,孔隙比为影响浸矿效果和矿体稳定性的关键因素.为探索不同孔隙比下风化壳淋积型稀土矿强度特性变化,选取6组重配比的稀土矿样,对不同孔隙比矿样进行了直接剪切实验,探讨孔隙演化对矿体抗剪强度的作用规律,揭示孔隙比对黏聚力和内摩擦角的影响机制.研究表明:不同孔隙比非饱和稀土矿对应着不同的剪切强度,基于试验数据发现剪应力与剪位移呈"类抛物线"变化,并建立了孔隙比与抗剪强度指标的关系模型.机制分析认为,随着孔隙比的增大,结合水膜效应逐渐弱化,粒间接触点数目也随之减少,使矿体抗剪强度减小.     

Recovery of valuable metals from a low-grade nickel ore using an ammonium sulfate roasting-leaching process

Metal leaching from a low-grade nickel ore was investigated using an ammonium sulfate roasting-water leaching process. The nickel ore was mixed with ammonium sulfate, followed by roasting and finally leaching with water. During the process the effects of the amount of ammonium sulfate, roasting temperature, and roasting time on the leaching recovery of metal elements were analyzed. The optimum technological parameters were determined as follows:ammonium sulfate/ore ratio, 0.8 g/g; roasting temperature, 400℃; and roasting time, 2 h. Under the optimum condition the leaching recoveries of Ni, Cu, Fe, and Mg were 83.48%, 76.24%, 56.43%, and 62.15%, respectively. Furthermore, the dissolution kinetics of Ni and Mg from the nickel ore was studied. The apparent activation energies for the leaching reaction of Ni and Mg were 18.782 and 10.038 kJ·mol-1, which were consistent with the values of diffusion control reactions. Therefore, the results demonstrated that the leaching recoveries of Ni and Mg were controlled by diffusion.     

南方重稀土矿浸取动力学分析

探讨了浸取反应温度、浸取剂初始浓度，矿石粒度及搅拌强度对浸取速率的影响，并进行了浸取动力学分析。结果显示，其浸取过程可用收缩未反应芯模型表达，属内扩散控制，求出了表观活化能，导出了动力学方程，为高效，低耗合理地开采南方重稀土提供了科学的途径和理论依据。     

次生硫化铜矿微生物浸出实验

微生物浸矿是提取低品位,难选次生硫化铜矿中有价元素的最有效方法之一.本研究利用嗜酸氧化亚铁硫杆菌(Acidthiobacillus ferrooxidans)浸取福建某难选次生硫化铜矿,依次开展浸矿菌富集培养实验、驯化转代实验和不同粒径配比下柱浸试验,获得了不同阶段的细菌浓度、pH值、铜浸出率等演变规律;并结合电子计算机断层扫描技术实现了柱内矿堆塌落、截面孔隙演化和浸矿机理研究.研究表明:细菌浓度和pH值均呈现缓慢增加后趋降低的趋势,浸柱中细菌增殖较慢,浸矿480 h后,细菌浓度仅为每毫升5×107个.浸矿过程中,细颗粒趋于向柱底迁移,矿堆出现塌落;柱顶孔隙率变大,增幅为6.65%,柱底孔隙率变小,降幅为8.29%;塌落程度与细粒含量成正比,最小塌落为1.7 mm,最大塌落为6.15 mm.入堆矿石粒径极大影响着柱浸体系的浸出效果.实验中柱浸B组(粒径r<1 mm占28.41%)浸矿效果最佳,浸矿480 h后铜浸出率达47.23%.     

Reductive leaching of manganese from low-grade pyrolusite ore in sulfuric acid using pyrolysis-pretreated sawdust as a reductant

Manganese (Mn) leaching and recovery from low-grade pyrolusite ore were studied using sulfuric acid (H₂SO₄) as a leachant and pyrolysis-pretreated sawdust as a reductant. The effects of the dosage of pyrolysis-pretreated sawdust to pyrolusite ore, the concentration of sulfuric acid, the liquid/solid ratio, the leaching temperature, and the leaching time on manganese and iron leaching efficiencies were investigated. Analysis of manganese and iron leaching efficiencies revealed that a high manganese leaching efficiency was achieved with low iron extraction. The optimal leaching efficiency was determined to be 20wt% pyrolysis-pretreated sawdust and 3.0 mol/L H₂SO₄ using a liquid/ solid ratio of 6.0 mL/g for 90 min at 90℃. Other low-grade pyrolusite ores were tested, and the results showed that they responded well with manganese leaching efficiencies greater than 98%.     

(NH4)2SO4-NH3-H2O体系浸出高碱性脉石低品位氧化铜矿

以高碱性脉石低品位氧化铜矿为研究对象,针对该矿样钙镁含量高的特点,采用氨水-硫酸铵浸出体系进行了常温常压浸出实验.针对该矿样的主要含铜矿物孔雀石(Cu₂(OH)₂CO₃),基于质量和电荷的双守恒的条件下构建的浸出体系中建立Cu₂(OH)₂CO₃-(NH₄)₂SO₄-NH₃-H₂O的热力学模型,采用Matlab的拟合功能与diff和solve函数算出不同硫酸铵浓度时氨浸出孔雀石的最佳氨浓度和总铜离子浓度.实验考察了浸出氨水浓度、氨铵比、液固比对铜浸出率的影响.实验结果表明,高碱性脉石氧化铜矿石适宜浸出条件为氨水浓度1.2mol/L,氨铵比2∶1,液固比3∶1,该条件下铜浸出率较高,达到约70%.实验结果与热力学计算结果基本吻合.     

用复合浸出剂浸取风化壳淋积型稀土矿中的稀土研究

研究了采用新型复合浸出剂来浸取风化壳淋积型稀土矿中的稀土,结果表明：新型复合浸出剂浸取稀土浸出率高于单一浸取剂,能减少某些非稀土杂质元素的浸出,浸取后的浸出剂经提纯后能反复使用,而且这种新的稀土浸出剂具有来源广、价格便宜、不污染环境等优点,有推广应用价值。     

Computer modeling of high-pressure leaching process of nickel laterite by design of experiments and neural networks

Due to the complex chemical composition of nickel ores, the requests for the decrease of production costs, and the increase of nickel extraction in the existing depletion of high-grade sulfide ores around the world, computer modeling of nickel ore leaching process became a need and a challenge. In this paper, the design of experiments (DOE) theory was used to determine the optimal experimental design plan matrix based on the D optimality criterion. In the high-pressure sulfuric acid leaching (HPSAL) process for nickel laterite in "Rudjinci" ore in Serbia, the temperature, the sulfuric acid to ore ratio, the stirring speed, and the leaching time as the predictor variables, and the degree of nickel extraction as the response have been considered. To model the process, the multiple linear regression (MLR) and response surface method (RSM), together with the two-level and four-factor full factorial central composite design (CCD) plan, were used. The proposed regression models have not been proven adequate. Therefore, the artificial neural network (ANN) approach with the same experimental plan was used in order to reduce operational costs, give a better modeling accuracy, and provide a more successful process optimization. The model is based on the multi-layer neural networks with the back-propagation (BP) learning algorithm and the bipolar sigmoid activation function.     

Preparation of manganese sulfate from low-grade manganese carbonate ores by sulfuric acid leaching

In this study, a method for preparing pure manganese sulfate from low-grade ores with a granule mean size of 0.47 mm by direct acid leaching was developed. The effects of the types of leaching agents, sulfuric acid concentration, reaction temperature, and agitation rate on the leaching efficiency of manganese were investigated. We observed that sulfuric acid used as a leaching agent provides a similar leaching efficiency of manganese and superior selectivity against calcium compared to hydrochloric acid. The optimal leaching conditions in sulfuric acid media were determined; under the optimal conditions, the leaching efficiencies of Mn and Ca were 92.42% and 9.61%, respectively. Moreover, the kinetics of manganese leaching indicated that the leaching follows the diffusion-controlled model with an apparent activation energy of 12.28 kJ·mol-1. The purification conditions of the leaching solution were also discussed. The results show that manganese dioxide is a suitable oxidant of ferrous ions and sodium dimethyldithiocarbamate is an effective precipitant of heavy metals. Finally, through chemical analysis and X-ray diffraction analysis, the obtained product was determined to contain 98% of MnSO₄·H₂O.     

类砂岩型矿石浸出液质量浓度混沌时序重构与浸矿周期预测

以河砂、水泥和盐为原料制作类砂岩型矿石试件,采用水浸的方式对不同品位矿石进行浸矿试验,对浸出液质量浓度进行监测. 考察了浸出液质量浓度和浸出率随浸矿时间演变规律;将浸出液质量浓度时间序列进行相空间重构,用混沌理论揭示了不同品位矿石浸出液质量浓度在相空间中相点距演化规律;利用灰色理论,建立了浸出液质量浓度相点距演化预测模型,确定合理的浸矿周期. 研究发现:浸出液质量浓度表现出混沌特性,对其进行相空间重构处理后,细微变化特征得以放大,内部规律得以充分展现;不同品位矿石表现出不同的非线性动力学行为;利用基于相空间重构的残差修正灰色模型预测了浸矿周期,为溶浸采矿理论与技术提供了一种新的研究和探讨方法.     

微波辅助双水相提取苦荞麦粉中黄酮类化合物

采用微波辅助乙醇-硫酸铵双水相体系,从苦荞麦粉中提取黄酮类化合物.确定乙醇-硫酸铵双水相提取黄酮类化合物的较优乙醇体积分数以及硫酸铵添加量;通过单因素实验确定苦荞麦粉黄酮类化合物的较优萃取条件.结果表明:微波辅助双水相的方法适合用于苦荞麦粉中黄酮类化合物的提取;响应面法优化微波辅助双水相提取苦荞麦粉黄酮的提取条件,较优提取条件为萃取剂含乙醇的体积分数30%,微波功率550 W,提取时间70 s,苦荞麦粉在提取溶剂中的质量浓度0.02 g/m L,苦荞麦粉中提取得到的黄酮类化合物占苦荞麦粉的质量分数为1.38%.     

硫酸铵腐蚀环境下的混凝土碳化深度试验研究与应用

硫酸盐腐蚀是影响混凝土结构耐久性能的重要化学劣化因子之一。以赣南离子型稀土开采残留硫酸铵的环境问题为背景,通过实验室快速碳化试验研究硫酸铵溶液浓度对混凝土碳化深度的影响规律。结果表明:硫酸铵溶液浓度越大,相同强度等级的混凝土在相同碳化龄期的碳化深度与碳化速率越大。根据试验结果建立了硫酸铵腐蚀环境下混凝土碳化深度预测模型,对该环境下混凝土最小保护层厚度取值提出了建议。     

离子型稀土矿原地溶浸溶浸液渗流规律的影响因素

根据离子型稀土矿具有黏土矿物性质,矿物颗粒表面结合水对溶浸液具有粘滞和吸收作用,并能缩小孔隙体积的特点,探讨了矿物颗粒表面结合水的形成机理及其对溶浸液渗流规律的影响.研究结果表明:离子型稀土矿具有B型颗粒结构特征,松散矿物颗粒在满足起动临界水力梯度和颗粒几何尺寸的条件下阻塞孔隙;表面结合水和松散颗粒是影响原地溶浸离子型稀土矿溶漫液渗流规律的2个主要因素.     

从风化壳淋积型稀土矿浸取液提取稀土技术与发展

详细评述了从风化壳淋积型稀土矿浸取液提取稀土方法,包括草酸沉淀法、碳酸氢铵沉淀法、沉淀浮选法、溶剂萃取法、离子交换法、液膜分离法及微生物吸附法等。草酸沉淀法因沉淀剂有毒、成本高,已被淘汰。碳酸盐沉淀法因沉淀剂无毒、成本低,成为目前生产实际中的应用方法,但仍存在氨氮污染,面临新挑战。对于溶剂萃取法和微生物吸附法等非沉淀提取法,已成为研究热点,符合绿色化学发展趋势,有良好应用前景。     

一株硫酸铵耐性菌株的分离鉴定及其特征研究

本研究以赣州稀土矿区尾矿土壤微生物为研究对象,利用限制性片段长度多态性(restriction fragment length polymorphism, RFLP)技术,获得一株硫酸铵耐性菌株。通过16 S rDNA序列测定,鉴定该菌株属于短波单胞菌属(Brevundimonas sp.),命名为Brevundimonas sp. LNa,该菌株对硫酸铵的最高耐受浓度可达0.9 mol/L。进一步研究了环境因素对菌株LNa生长的影响,并表征其生理生化特性。结果表明:菌株LNa对硫酸链霉素不敏感,在低于1 mol/L硫酸铵处理,pH在6-7.5之间,菌株均能正常生长。菌株LNa能不同程度地降低培养基中氨氮和硫酸盐浓度,在0.7 mol/L硫酸铵胁迫下降解效果最好,氨氮浓度能降低约29%,硫酸盐浓度降低约36.7%;随着硫酸铵胁迫浓度的升高,菌株LNa的FDA水解酶(Fluorescein diacetate, FDA)、蛋白酶、脱氢酶和过氧化氢酶的活性都有不同程度的降低,当浓度上高到0.6 mol/L后,菌株的过氧化氢酶活性将不再发生变化。LNa菌株对氨氮和硫酸盐的降解能力,可能与细菌FDA水解酶和蛋白酶活性的分泌有关。     

基于不同粒级硫化铜矿石生物浸出的动力学

西藏甲玛地区的硫化铜矿石中含铜矿物以次生硫化铜矿物为主,且含量较低.采用氧化亚铁硫杆菌柱浸的方法对该矿石进行了生物浸出并研究了浸出动力学.基于不同粒级矿石,考察了粒级对铜浸出速率和浸出率的影响,并对浸出率与收缩核模型中的控制方程进行了拟合,确定了浸出过程的控速环节.试验结果表明,铜的浸出速率和浸出率随粒级的减小而增加.矿石表面形貌的SEM表明,浸出过程中矿石表面形成了包含黄钾铁矾的产物层,阻碍了浸出反应的进行.浸出动力学表明,该矿石的浸出过程符合收缩核模型,且浸出应主要受固体产物层内扩散控制.     

低品位原生金矿的生物柱浸

采用粘结剂S-11将某低品位原生金矿的精矿粘结包裹在其原矿矿石上进行生物柱浸与原矿生物柱浸的对比研究.主要研究了生物柱浸过程中Fe2+浓度,pH,Eh,矿石表面吸附的细菌及菌液中游离细菌数量的变化、矿石的脱砷率、脱硫率,生物柱浸后矿石金的氰化浸出率.结果表明:金精矿包裹后的矿石表面因含硫化矿物较多,更适合细菌的吸附与繁殖;包裹生物柱浸120 d后矿石的脱砷率为70.14%,脱硫率为41.26%,金的氰化浸出率为81.21%,比传统生物柱浸矿石的脱砷率、脱硫率和浸金率分别高24.01%,19.11%和21.48%.包裹生物柱浸对矿石的氧化效果明显.