Microwave assisted atmospheric acid leaching of nickel from laterite ore

The recovery of nickel from laterite ore with sulphuric acid under the effect of microwave irradiation was studied.The experimental results indicated that the extraction rate of nickel was influenced by reaction time,sulphuric acid concentration,and temperature,especially by microwave power.The results obtained from the experiments of orthogonal arrays showed that the optimum conditions of sulphuric acid concentration,reaction time,microwave power,and temperature were 25 vol.%,1.5 h,600 W,and 90°C,respectively.Under the optimal conditions,the nickel recovery could reach approximately 90.8%,which was higher than that obtained by conventional water bath heating.Kinetic experiments showed that the leaching of nickel in a sulphuric acid medium was controlled by chemical reaction occurring on the surface of laterite ore.The apparent activation energy was 38.9 kJ/mol.Microwave heating technology is efficient,clean,and easy to control and facilitate continuous processing of materials.

Leaching behavior of metals from limonitic laterite ore by high pressure acid leaching

The leaching behavior of metals from a nickeliferous limonitic laterite ore was investigated by high pressure acid leaching process for the extraction of nickel and cobalt.The effects of sulfuric acid added,leaching temperature,leaching time and liquid/solid（L/S） ratio on metals extraction were examined.More than 97% Ni,96% Co,93% Mn,95% Mg and less than 1% Fe are extracted under optimum conditions.Analysis of the high pressure acid leaching residue by chemical and XRD analysis indicates that the residual iron and sulfur are mainly present in phases of hematite and alunite,respectively.The high pressure leaching process provides a simple and efficient way for the high recovery of nickel and cobalt from laterite ore,leaving residue as a suitable iron resource.

Kinetic study on leaching of nickel from Turkish lateritic ore in nitric acid solution

Dissolution kinetics of nickel from lateritic ore in nitric acid solution was investigated. Experimental parameters used were stirring speed(100-600 r/min), temperature(40-96 °C), nitric acid concentration(0.1-2 mol/L) and particle size(<106 μm). The shrinking core model was applied to the results of experiments investigating the effects of leaching temperature in the range of 40-90 °C and nitric acid concentration in range of 0.1-2 mol/L on nickel dissolution rate. The kinetic analysis shows that the nickel dissolution from lateritic ore could be described by diffusion model. The activation energy(E_a) for the dissolution reaction is calculated as 79.52 kJ/mol.

Synthesis and characterization of Co_3O_4 prepared from atmospheric pressure acid leach liquors of nickel laterite ores

A chemical precipitation-thermal decomposition method was developed to synthesize Co3O4 nanoparticles using cobalt liquor obtained from the atmospheric pressure acid leaching process of nickel laterite ores. The effects of the precursor reaction temperature, the concentration of Co2＋, and the calcination temperature on the specific surface area, morphology, and the electrochemical behavior of the ob- tained Co304 particles were investigated. The precursor basic cobaltous carbonate and cobaltosic oxide products were characterized and ana- lyzed by Fourier transform infrared spectroscopy, thermogravimetric differential thermal analysis, X-ray diffraction, field-emission scanning electron microscopy, specific surface area analysis, and electrochemical analysis. The results indicate that the specific surface area of the Co3O4particles with a diameter of 30 rim, which were obtained under the optimum conditions of a precursor reaction temperature of 30℃, 0.25 mol/L Co2＋, and a calcination temperature of 350℃, was 48.89 m2/g. Electrodes fabricated using Co3O4 nanoparticles exhibited good electrochemical properties, with a specific capacitance of 216.3 F/g at a scan rate of 100 mV/s.

Nickel extraction from low grade laterite by agitation leaching at atmospheric pressure

This research work deals with the extraction of nickel from a low grade nickel laterite ore, taken from a deposit located in southwestern of Iran, through agitation leaching at atmospheric pressure. The assaying and mineralogical studies carried out on the nickel laterite sample, showed the 0.88% Ni, and principally consisted of oxide and silicate crystalline phases i.e. dolomite, quartz, magnetite, and goethite. Among numerous factors affecting such process, four major parameters i.e. temperature, agitator speed(r/min), leaching agents and their concentration were considered in a two-level full factorial experimental design. The agitation leach tests showed that the ore could be leached at atmospheric pressure with sulfuric acid while citric acid was almost unpromising. Analysis of variance(ANOVA) using DX7 software was employed to identify effective parameters. Sulfuric acid concentration and temperature were the most effective parameters on Ni extraction. Furthermore, the factorial models for experiment responses were developed. The results showed 83% Ni extraction after 4 h leaching, under optimized conditions i.e.temperature at 95 ℃, acid concentration at 5 N and agitator speed at 1000 r/min. This study revealed that factorial experimental design can be implemented to identify effective parameters on the agitation leaching process of nickel laterite.

A new route of ferric ions rejection in a synthetic nickel leach solution

A new route of impurity rejection to remove ferric iron from a synthetic nickel leach solution was introduced, which simulated the chemical composition of a typical acid leach solution of nickel laterites under atmospheric pressure. The synthetic solution underwent a stepwise neutralization process, with each step adopting different pH value-temperature combinations. In a conventional nickel atmospheric leach （AL） process, the nickel loss could be as high as 10wt%, which was a longstanding issue and prevented this process from commercialization. The new impurity rejection route is the first step towards resolving this issue. The results show that, the best neutralization performance is achieved at the nickel loss of 3.4wt% in the neutralization scheme that employs ethylenediaminetetraacetic acid as a nickel stabilizer （pH： 1.3-3.5; temperature： 95-70℃）

红土镍矿酸浸渣综合利用进展

近年来随着不锈钢及新能源用镍需求的增长,红土镍矿湿法提镍工艺得到更多应用,相应的红土镍矿酸浸渣堆存量也迅速增加,对此类固废进行科学消纳和资源综合利用迫在眉睫。针对红土镍矿酸浸渣有害元素硫、有价金属铁含量高的特点进行综合利用新技术、新装备研究对红土镍矿湿法冶金工业的持续发展具有重要的理论和现实意义。主要介绍红土镍矿酸浸渣的湿法冶金形成过程及其成分组成和物理化学性质,较为系统地梳理了红土镍矿酸浸渣在尾矿坝堆积、地下压滤回填和深海填埋等直接处理方法,提取利用铁、铬、铝、稀土等有价金属资源,消纳制备硅藻土、陶粒、矿物纤维等建筑材料、制备锂电池电极、沸石等高附加值材料综合利用技术上的研究进展,展望了红土镍矿酸浸渣流态化提铁降硫技术及装备的发展前景。

褐铁矿型红土镍矿中有价金属的酸浸工艺

镍是一种战略性稀有金属,从低品位红土镍矿中生产单质镍或镍的合金是解决镍铁合金需求的主要途径。采用盐酸选择性浸出印尼褐铁矿型红土镍矿中的有价金属,结果表明:当盐酸浓度10 mol/L,原料粒度74μm,浸出温度353 K,固液体积比1∶4,浸出时间120 min时,镍、钴、锰、铁和镁的浸出率分别为34.3%、90.67%、64.23%、76.46%和48.12%,且盐酸作为常见的工业副产品,易回收再生。镍、钴、锰的浸出动力学研究可知,其浸出过程不符合广泛采用的收缩核模型,而用Avrami方程进行拟合具有很好的线性,根据Arrhenius公式求得浸出过程中镍、钴和锰的表观活化能分别为7.96、4.00kJ/mol和4.98 kJ/mol,三者浸出的活化能值均介于4~12 kJ/mol范围内,且浸出温度对反应速率常数的影响并不明显,判断出镍、钴和锰的浸出过程受扩散条件控制。本研究结果可为褐铁矿型红土镍矿的高效开发利用提供理论参考。

褐铁型红土镍矿硫酸高压浸出矿物结构变化

菲律宾某矿区典型褐铁型红土镍矿的工艺矿物学分析表明,矿样中主要的矿物为针铁矿、铬尖晶石、石英及其他黏土质矿物,镍、钴主要赋存在铁矿物中。基于矿物特性,选择采用硫酸高压浸出工艺对该矿物进行处理,在100 g矿酸用量29 g、温度250℃、液固比3 mL/g、反应时间30 min的条件下,镍、钴浸出率均超过95%,铁浸出率低于1%,实现了镍、钴的选择性浸出。浸出渣的工艺矿物学分析表明,浸出过程中,原矿中的针铁矿矿相被破坏,赋存在其中的镍、钴被浸出进入溶液,未被浸出的镍、钴赋存于铬尖晶石中,这是镍、钴浸出不完全的主要原因。浸出渣中主要的含硫物相是铝水解生成的明矾石和铁水解夹带的部分硫酸镁等硫酸盐,二者均与铁矿物结合较紧密。

红土镍矿硝酸加压浸出渣制备电池级磷酸铁

近年来,在我国“碳达峰”和“碳中和”目标的引领下,新能源行业发展迅速,新能源汽车的推广与使用促进了锂离子电池行业的蓬勃发展。作为三元锂电池的关键原材料,镍的需求量不断增加。但由于硫化镍矿日益枯竭,红土镍矿逐渐成为了主要的提镍原料,在镍产量中占比超过70%。褐铁型红土镍矿在红土镍矿中占比超过60%,经硝酸加压浸出(NAPL)提取镍钴后产生的浸出渣中含有丰富的有价金属资源(铁含量>60%),浸出渣的综合利用对资源回收和环境保护具有重要意义。以褐铁型红土镍矿硝酸加压浸出渣为原料,在磷酸单一介质中制备电池级磷酸铁材料。以磷酸为介质,通过预浸、溶解实现浸出渣中铁的高效提取。预浸时磷酸溶液浓度较低,可以使含铁相初步转型为FePO_(4)·2H_(2)O,同时除去浸出渣中Cr、Mg、Al等杂质元素。然后采用高浓度磷酸溶液溶解处理预浸渣,实现Fe的完全溶解。最后稀释调节pH值直接沉淀制备磷酸铁,得到FePO_(4)·2H_(2)O产品,该产品不含杂质元素Mg、Si,Cr、Al的含量为0.019%、0.016%。通过XRD、SEM、EDS等技术手段对预浸渣和磷酸铁产品的物相组成和微观形貌进行了研究,明确了预浸过程可实现铁由Fe_(2)O_(3)向FePO_(4)·2H_(2)O的转变,最终产品的晶体结构与标准磷酸铁相匹配。由磷酸铁合成的磷酸铁锂材料也表现出优异的电化学性能。该研究有望实现对褐铁型红土镍矿硝酸加压浸出渣中宏量组元铁的高值化利用,从而优化磷酸铁制备工艺。

某红土型镍矿中镍钴的赋存状态对其回收的影响

褐铁矿型红土镍矿是一种富含镍、钴、铁的重要资源,综合利用价值巨大。探究红土型镍矿中镍和钴的赋存状态,以深入了解赋存状态对镍和钴回收利用的影响。通过详细的工艺矿物学研究,明确镍和钴主要赋存于褐铁矿、锰的水合氧化物和锰镍矿中,根据该红土型镍矿特征判断最佳冶炼回收方法为高压酸浸工艺。研究为红土型镍矿的资源高效利用提供了重要参考,为相关工业应用和环境保护提供了有益启示。

高铁低品位红土镍矿酸浸工艺研究

研究了用硫酸从印尼某高铁低品位红土镍矿中加压酸浸镍、钴、铁,并探讨了浸出渣中铁品位变化及常压、加压下的浸出动力学。结果表明:在酸矿比260 kg/t、温度250℃(对应水蒸气压力4.0 MPa)、液固体积质量比3/1、搅拌速度300 r/min、粒度100目、反应时间1 h条件下,镍、钴、铁浸出率分别为98.1%、98.3%、4.7%,铁品位可达51.3%;加压和常压下,镍、钴浸出过程均符合界面化学反应控制的收缩核模型,加压下反应活化能分别为116、91 kJ/mol,常压下反应活化能分别为41、53 kJ/mol;常压下主要是针铁矿的浸出,高压下主要是铬铁矿、磁铁矿等矿相的浸出。

红土镍矿高压酸浸技术优化研究

近年来,印度尼西亚掀起高压酸浸项目投资热潮,多个项目已投产或处于规划中。项目一般由中方背景主导,技术成熟,装备可靠,单位投资较低,建设速度较快,运营经验丰富,爬坡期较短,单线产能大,装备国产化趋势明显。高压酸浸(High Pressure Acid Leach,HPAL)技术优化涉及4个重点,一是提高原矿浆浓密底流浓度,二是预热方式优化,三是一段沉镍钴流程优化,四是沉镍钴沉淀剂优化。高压酸浸技术主要有5个发展方向,即尾渣综合利用、关键设备国产化替代、增加高压釜长度、配矿和锰综合回收利用。本文结合近年来红土镍矿高压酸浸技术的发展特点,分析高压酸浸技术优化重点,指出高压酸浸技术发展方向,为新建项目的规划和运营提供有效指导。

红土矿火法产镍铁粉处理新工艺研究

本文提出了一种利用红土矿生产氢氧化镍钴的新工艺,即直接采用火法还原红土矿产出粗镍铁粉,粗镍铁再经过硝酸选择性浸出镍钴、深度除铁铬铝和镍钴沉淀等湿法工序,产出氢氧化镍钴产品;在回收镍钴的同时,铁以铁精矿形式开路,镍回收率可达99%,直收率达97%,钴直收率达98%,铁直收率达95%。整个湿法工艺用水、浸出剂和沉淀剂可循环利用,全流程只有火法渣外排,无废水和湿法渣外排,是一条清洁环保的红土矿强化冶金新工艺。

红土镍矿两段加压提镍新工艺

采用两段加压新工艺联合处理褐铁矿型红土镍矿和蛇纹石型红土镍矿。推荐一段高压酸浸工艺条件为:酸矿比330 kg/t、温度250℃、矿浆浓度30%、反应时间1 h;推荐二段加压浸出工艺条件为:温度230℃、时间1 h、矿浆浓度35%。一段高压酸浸镍浸出率97.58%,二段蛇纹石镍浸出率83.96%,镍总浸出率93.81%,极大提高了镍资源的利用率;二段加压浸出液铁、铝可降至1 g/L以下,可以减少后续中和工序的用碱量。

褐铁矿型和蛇纹石型红土镍矿提取镍钴的工艺研究

红土镍矿成分复杂,镍与钴的含量较低,主要类型有褐铁矿型和蛇纹石型。试验采用不同工艺对两种红土镍矿进行浸出,从而提取镍和钴。褐铁矿型红土镍矿采用拌酸熟化-水浸工艺进行处理。试验结果表明,当硫酸和红土镍矿的质量比为1.84时,镍与钴的浸出率均超过97%,酸度越高,镍与钴的浸出率也越高;不管是先拌酸熟化再浸出,还是直接浆化加酸浸出,对镍与钴的浸出率影响不明显;在浸出过程中,添加还原剂,可使钴浸出率超过96%,还原剂的加入有利于钴的浸出,但对镍的浸出影响不大。蛇纹石型红土镍矿则采用常压预浸-加压浸出工艺进行处理。试验结果表明,当总酸矿比为0.53~0.58 t/t矿时,镍与钴的浸出率均超过74%,加压浸出液的铁含量约为5 g/L,残酸含量为15~21 g/L。

柠檬酸-草酸体系处理红土镍矿可行性探索研究

研究了红土镍矿低温、绿色化提取的新工艺。传统冶金工业面临的主要压力是能源和环保问题,本研究利用自然界中存在的柠檬酸和草酸两种有机酸为提取试剂,力求在低温下实现红土镍矿的有效提取。研究以低品位红土镍矿为原料,采用与柠檬酸混合焙烧-水浸-草酸沉淀工艺实现镍钴的有效富集。考察了焙烧条件和浸出条件对红土镍矿中多种金属浸出率的影响,也探究了利用草酸从浸出液中直接沉淀镍离子的可行性。结果表明,当焙烧温度为140℃时,镍、钴、铁的浸出率分别为97.70%,97.94%,95.94%,当焙烧温度为100℃时,镍和钴浸出率均可以保持在87%以上,而铁浸出率降低到42.83%,这表明较低温度的焙烧对于红土镍矿中有价金属的浸出具有一定的选择性;利用超声浸出可有效地提高浸出效率;控制浸出温度在较低温度,焙烧产物中的金属浸出依然具有选择性,即镍钴浸出不受影响,而铁浸出率降低显著;以草酸为沉淀剂,无需要调节pH值即可从柠檬酸浸出液体系中沉淀金属,所得草酸盐沉淀为草酸镍和草酸镁混合物,铁几乎不沉淀。

Pressure nitric acid leaching of alkali-pretreated low-grade limonitic laterite

The pressure nitric acid leaching of alkali-pre- treated low-grade limonitic laterite, as well as removing impurity AI（III） and preparing intermediate product of nickel/cobalt sulphide from leaching liquor were investi- gated. After pretreatment, iron exists in the form of amorphous iron oxides, while nickel is adsorbed on the surface of iron oxides in the form of nickel oxide. The preferable pressure leaching conditions are determined as follows： leaching temperature of 458 K, leaching duration of 60 min, initial acidity of nitric acid of 1.90 mol.L-~ and liquid to solid ratio of 3：1 （volume to mass ratio）. Under these conditions, the leaching efficiencies of Ni, Co and A1 are 95 %, 88 % and 55 %, respectively, and that of Fe is less than 1%. The loss rates of Ni and Co are 1.8 % and 1.5 %, respectively, during the step of removing impurity AI（III）. The sulphide precipitation process produces the interim production of nickel/cobalt sulphides, recovering greater than 99 % of Ni and Co in the purified solution. The iron-rich （〉60 %） pressure leaching residue with low Cr, S can be further reclaimed as the raw materials for iron making.

红土镍矿浸渣选铁试验研究

针对某含铁51.38%、含硫2.01%的红土镍矿浸渣进行了离心选矿、磁选、磁化焙烧等试验研究。结果表明,磁化焙烧-磁选工艺是该红土镍矿浸渣选铁的高效分选工艺。煤基还原-弱磁选获得了精矿TFe品位62.77%、回收率94.04%的指标;气基还原-弱磁选获得了精矿TFe品位68.77%、回收率95.15%、精矿中杂质硫含量0.12%的指标,可达到铁精矿质量要求;直接还原-弱磁选可获得精矿TFe品位90.89%、回收率88.90%的指标,但存在精矿中硫含量偏高的问题。

基于METSIM的红土镍矿高压酸浸平衡模拟计算

红土矿高压酸浸系统的平衡计算是整个系统的关键,本文利用METSIM软件对红土镍矿高压酸浸系统的平衡进行模拟计算,通过计算系统的物料平衡、热平衡,为高压酸浸系统的工程化提供数据支持,并利用该软件对实际生产过程的不同操作情况下的操作参数进行修正,得到的平衡数据可用于进一步指导实际生产的稳定。