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 amotmt 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 ofNi, 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.mo1-1, 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.

Effects of additives on nickel electrowinning from sulfate system

In order to eliminate the pitting and improve the surface morphology of cathode nickel,the influence of additives of boric acid and dodecyl sodium sulfate(SDS)on the process of nickel electrowinning from sulfate system was studied by cathode polarization tests and nickel electrodeposition experiments.The experimental results show that the addition of boric acid can increase the cathode polarization while SDS can decrease the cathode polarization.Both boric acid and SDS are useful to eliminate the pitting on nickel deposits and improve the morphology of surface.Good deposit morphology with rare pitting and high current efficiency is favored by adding 10 g/L boric acid and 40 mg/L SDS in the electrolyte under the condition of nickel ion concentration of 80 g/L, sodium ion concentration of 10 g/L,pH of 3,current density of 220 A/m 2 and temperature of 70℃.

Separation and recovery of Ni from copper electrolyte by crystallization of nickel ammonium sulfate double salt

The separation and recovery of Ni from the copper electrolyte by crystallization of nickel ammonium sulfate double salt were studied.It is found that the solubility of copper sulfate at the same temperature is less than that of nickel sulfate,while the solubility of copper ammonium sulfate is greater than that of nickel ammonium sulfate.So,by adding(NH_(4))_(2)SO_(4),the Ni can be selectively crystallized from the copper electrolyte.By adding(NH_(4))_(2)SO_(4)at the molar ratio of(NH_(4))_(2)SO_(4)/NiSO_(4)≤0.8,and crystallizing at−15℃for 10 h,the Ni in the copper electrolyte can be crystallized in the form of Ni(NH_(4))_(2)(SO_(4))_(2)×6H_(2)O.The qualified product of NiSO_(4)×6H_(2)O can be obtained by pyrolyzing the crystals,dissolving the pyrolysis product in water,and then concentrating the dissolved solution for crystallization.The method of double salt crystallization is a clean,environmentally-friendly,cost-effective and efficient method for separating and recovering nickel from copper electrolyte.

Alteration of chemical behavior of L-ascorbic acid in combination with nickel sulfate at different pH solutions in vitro

Objective:To evaluate the alteration of chemical behavior of L-ascorbic acid(vitamin C) with metal ion(nickel) at different pH solutions in vitro.Methods:Spectra of pure aqueous solution of L-ascorbic acid(E mark) compound and NiSO_4(H_2O)(sigma USA) were evaluated by UV visible spectrophotometer.Spectral analysis of L-ascorbic acid and nickel at various pH(2.0, 7.0,7.4 and 8.6) at room temperature of 29℃ was recorded.In this special analysis,combined solution of L-ascorbic acid and nickel sulfate at different pH was also recorded.Results:The result revealed that λ_(max)(peak wavelength of spectra) of L-ascorbic acid at pH 2.0 was 289.0 run whereas at neutral pH 7.0,λ_(max) was 29S.4 run.In alkaline pH 8.6,λ_(max) was 295.4 nm and at pH 7.4 the λ_(max) of L-ascorbic acid remained the same as 295.4 nm.Nickel solution at acidic pH 2.0 was 394.5 nm,whereas at neutral pH 7.0 and pH 7.4 were the same as 394.5 nm.But at alkaline pH 8.6,λ_(max) value of nickel sulfate became 392.0 nm.The combined solution of L-ascorbic acid and nickel sulfate(6 mg/mL each) at pH 2.0 showed 292.5 nm and 392.5 nm,respectively whereas at pH 7.0,L-ascorbic acid showed 296.5 nm and nickel sulfate showed 391.5 nm.At pH 7.4,L-ascorbic acid showed 297.0 nm and nickel sulfate showed 394.0 nm in the combined solution whereas at pH 8.6(alkaline) L-ascorbic acid and nickel sulfate were showing 297.0 and 393.5 nm,respectively. Conclusions:Results clearly indicate an altered chemical behavior of L-ascorbic acid either alone or in combination with nickel sulfate in vitro at different pH.Perhaps oxidation of L-ascorbic acid to L-dehydro ascorbic acid via the free radical(HSc*) generation from the reaction of H,ASc + Ni(Ⅱ) is the cause of such alteration of λ_(max),value of L-ascorbic acid in the presence of metal nickel.

Nickel sulfate solution fluoride separation with hydrous zirconium oxide

Fluoride is an impurity in nickel sulfate production,which is required for electric vehicle batteries.Hydrous zirconium oxide(HZO)was evaluated for removing fl uoride from nickel sulfate solution.Maximum fluoride removal occurred at pH value 4 and optimal pH value is 4–5,considering Zr solubility.Fluoride availability decreases with pH due to hydrogen fluoride and zirconium fluoride aqueous species.Fluoride removal is initially rapid,with 50 wt.%removal in 7 min,followed by slow removal up to 68 wt.%after 72 h and follows second order rate kinetics.Fluoride removal was dominated by an ion exchange mechanism and resulting Zr–F bonds were observed using Fourier-transform infrared spectroscopy.The presence of nickel sulfate decreased loading capacity compared to a salt-free solution.HZO maintained adsorption capacity through five cycles of loading and regeneration.

Application of response surface methodology in optimizaing thesulfation-roasting-leaching process of nickel laterite

Nickel was recovered from nickel laterite using a sulfation-roasting-leaching process and the effects of operation parameters in- cluding acid addition, roasting temperature, and roasting time on nickel extraction and iron dissolution were investigated using response sur- face methodology （RSM）. Two second-order polynomial models of high significance were presented to show the relationship between the responses and the variables. The analysis of variance （ANOVA） showed high coefficients of determination （R2） of 0.894 and 0.980 for the two models, respectively. Optimum areas of 〉-80% Ni extraction and 〈5% Fe dissolution were obtained by the overlaid contours. Verification experiments in the optimum areas were conducted and the results indicate a close agreement with the predicted values obtained from the models.

Response surface design for nickel recovery from laterite by sulfation-roasting-leaching process

The present study deals with the nickel extraction and iron dissolution from nickeliferous laterite by a process of sulfation-roasting-leaching.To optimize the roasting process,response surface methodology(RSM)was utilized which employed two-level and two-factor full factorial central composite design(CCD).The factors of roasting temperature and time were studied. Experiments were carried out for fitting two non-linear regression models of nickel extraction and iron dissolution.Predicted values obtained were close to experimental values,indicating the suitability of the models.Three-dimensional surface plots and contour plot were helpful to predicting the results by performing only limited set of experiments.An area of nickel extraction from 75%to 78% and iron dissolution from 5%to 10%is obtained by an overlaid contour plot.The samples roasted at different temperatures and for different durations were characterized by XRD,which show a good agreement to iron dissolution analysis.

Synthesis and Characterizaion of a New Inorganic-organic Sulfate Compound——Crystal Structure of [Ni(H_2O)_6][H_2N(C_2H_4)_2NH_2](SO_4)_2

Ni(H_2O)_6][H_2N(C_2H_4)_2NH_2](SO_4)_2 is an inorganic-organic compound with a new open framework synthesized by hydrothermal method, and characterized by means of single-crystal diffraction and spectroscopic data. The compound crystallized in a monoclinic space group P2_1/n with a=1.29089(2) nm, b=1.06301(3) nm, c=1.33202(4) nm, β=114.0870(10)°, V=1.67127(8) nm 3, Z=4, and was solved by using the direct method and the least-squares refinement converged at R=0.0214[I>2σ(I)]. The structure consists of isolated Ni(H_2O)_6 octahedra and SO_4 tetrahedra, with both of them hydrogen-bonded to piperazine cations.

Crystallization of battery-grade lithium carbonate with high recovery rate via solid-liquid reaction

Lithium carbonate(Li_(2)CO_(3))stands as a pivotal raw material within the lithium-ion battery industry.Hereby,we propose a solid-liquid reaction crystallization method,employing powdered sodium carbonate instead of its solution,which minimizes the water introduction and markedly elevates one-step lithium recovery rate.Through kinetic calculations,the Li_(2)CO_(3)solid-liquid reaction crystallization process conforms by the Avrami equation rather than shrinking core model,which means the dissolution rate of Na_(2)CO_(3)is the most important factor affecting the reaction process.The effects of reaction conditions such as temperature and stirring speed on the Li_(2)CO_(3)precipitation behavior were evaluated.The results indicated that temperature is a most essential parameter than other reaction conditions or stirring speed.The exceptional 93%recovery of Li_(2)CO_(3)at 90℃with a remarkable purity of 99.5%was achieved by using 1.2 M ratio of Na_(2)CO_(3)/Li_(2)SO_(4).This method provides a new idea for the efficient preparation of battery-grade Li_(2)CO_(3).

硫酸镍生产中液-液萃取分离铁、锌和镍试验研究

通过对某公司的硫酸镍溶液的试验研究,采用P204做萃取剂进行液-液萃取分离Fe^(3+)、Zn^(2+)和Ni^(2+)的试验,Fe^(3+)萃取率>85%,反萃率达到90%;Zn^(2+)萃取率93%,反萃率在90%以上;Ni^(2+)基本不被萃取,回收率可达98%以上。通过对硫酸和盐酸的反萃小试结果对比,用P204做萃取剂盐酸反萃的三级连续萃取试验Fe^(3+)和Zn^(2+)的反萃率均>98%。

能源转型背景下全球镍资源供需形势分析

全球16%、中国22%的镍用于新能源汽车动力电池领域,使得该领域成为仅次于不锈钢的第二大消费部门,面对全球能源转型背景下镍在电池领域新的消费增长点,保障动力电池生产所需的镍资源可靠及可持续供应至关重要。中国是全球最大的镍资源消费国和进口国,分析全球镍资源供需及产业最新变化趋势对国家制定相关紧缺矿产资源产业链供应链稳定政策具有重要现实意义。根据全球新能源汽车产业用镍情况,分析原生镍消费结构、消费变化数据,运用部门分析法预测了2030年全球镍需求量。以全球镍储量、勘探预算变化、主要资源国资源储量变化、镍矿及镍中间品和原生镍生产,以及全球镍贸易总量数据为基础,开展全球镍资源供需和产业变化研究。研究结果表明:未来全球镍产量能够满足镍在电池领域的消费需求增长;硫酸镍和含镍生铁成为重要的原生镍产品;镍湿法冶炼中间品氢氧化镍钴和高冰镍取代镍豆和镍粉成为硫酸镍最经济的生产原料。据此提出加强镍资源供需走势研判、开展镍产品国家储备研究及资源回收利用技术研发等建议。

含砷含镍高酸硫酸铜结晶母液的综合利用

针对硫酸铜结晶母液含砷、含镍、高酸的特点,根据正交试验法,采用pH调控法依次进行中和、沉铜、沉镍工业试验,探究了反应时间和终点pH对分离效果的影响。结果表明,采用液碱调控母液pH能有效回收铜、砷、镍元素。中和反应最佳参数为:终点pH=2.5~3.0、反应时间1.5 h、反应自然升温,能够以铜砷渣形式回收98%以上的砷,并与镍成功分离;沉铜反应终点pH=6.0~6.5、反应时间1.0 h、反应温度80~90℃,能实现铜沉淀率>93%;沉镍反应终点pH=10.0~10.5、反应时间2.0 h,在室温下压滤,镍沉淀率>98%。母液经处理后得到的沉镍后液含铜<50 mg/L,含砷<5 mg/L,含镍<100 mg/L,母液得到有效处理,实现铜回收率>96%,砷回收率>98%,镍回收率>84%。

粗硫酸镍高值化研究

铜电解生产中副产品粗硫酸镍的精制提纯已成为铜冶炼企业新的利润增长点,鉴于此,重点介绍了“焙烧脱氨—溶解造液—氧化中和预除铁—P204萃取—蒸发结晶”工艺试验,并分析了精制硫酸镍项目所产生的经济效益。

一种硫酸镍干燥新工艺浅析

基于硫酸镍及其水合物特性,介绍了一种集干燥、冷却于一体的固定流化床干燥工艺,并配合尾气再循环等粉尘处理工艺,达到节能环保的要求。该系统处理量可达16 t/h以上,尾气系统处理量最多可减少45%,干燥物料能节省热量7000 cal/t。

利用镍钴矿渣回收硫酸镍、硫酸钴研究

某有色冶炼企业5000 t/a电积铜生产线由于原料不足,目前处于闲置状态,为了充分利用厂房和设备,拟以含镍钴矿渣为原料,生产精制硫酸镍、硫酸钴产品。本项目以附加值较高的三元材料前驱体原料电池级硫酸镍、硫酸钴为产品,不但可获得较为丰厚的利润,而且可抢占国家产业政策鼓励的新能源材料市场,在回收镍、钴的同时还可以较低成本回收铜、锌等金属,而且实现固体废物综合利用,减少固体废物产生,产生一定环境效益。

铜冶炼副产品粗硫酸镍提纯实验研究

通过采用“焙烧脱氨-溶解造液-氧化除铁-P204萃取除杂-蒸发结晶”工艺对铜电解副产品粗硫酸镍进行精制提纯。实验结果表明,经过40 min焙烧脱氨后,粗硫酸镍中几乎不存在铵根离子,以H_(2)O_(2)为氧化剂,Ni(OH)_(2)为中和剂,在反应时间为60 min,反应温度60~70℃,不调整酸度的条件下,铁、砷的脱除率分别为98.8%、94.3%;以P204为萃取剂,镍的萃取率仅为0.72%,杂质钙、铜、铁、锰、锌的萃取率都大于99%,萃余液中钙、铜、铁、锰、锌的浓度都低于10 mg/L;最终通过蒸发结晶得到的硫酸镍的主品位大于22%,达到行标HG/T 2824—2022的精制硫酸镍产品要求。

3种镍基合金晶间腐蚀敏感性对比

镍基合金具有较高的强度和良好的氧化性、抗腐蚀能力,但在特定环境下,易发生晶间腐蚀。由于晶间腐蚀是一种危害性很大的局部腐蚀现象,会导致设备的突然破坏,因此选择Inconel625、Inconel825、Inconel690共3种镍基合金,在硫酸铁-硫酸溶液中试验120h,计算腐蚀速率,并对3种耐蚀合金腐蚀速率进行对比。试验结果表明:镍基合金具有良好的耐晶间腐蚀性能,3种材料的抗硫酸铁-硫酸晶间腐蚀性能由高到低依次为Inconel690、Inconel825、Inconel625。

Generation process of FeS and its inhibition mechanism on iron mineral reduction in selective direct reduction of laterite nickel ore

Numerous studies have demonstrated that Na2SO4 can significantly inhibit the reduction of iron oxide in the selective reduction process of laterite nickel ore. FeS generated in the process plays an important role in selective reduction, but the generation process of FeS and its inhibition mechanism on iron reduction are not clear. To figure this out, X-ray diffraction and scanning electron microscopy analyses were conducted to study the roasted ore. The results show that when Na2SO4 is added in the roasting, the FeO content in the roasted ore increases accompanied by the emergence of FeS phase. Further analysis indicates that NaeS formed by the reaction of Na2SO4 with CO reacts with SiO2 at the FeO surface to generate FeS and Na2Si2Os. As a result, a thin film forms on the surface of FeO, hindering the contact between reducing gas and FeO. Therefore, the reduction of iron is depressed, and the FeO content in the roasted ore increases.

Influence of a-tocopherol on nickel induced alteration of serum lipid profile in male albino rats

We studied the effect of the simultaneous treatment withα-tocopherol(100 mg / kg;im) and nickel sulfate (20 mg/kg,ip) on nickel-induced changes in serum lipid profiles.Nickel-treated rats showed a significant increase in serum LDL cholesterol,total cholesterol,triglycerides,and a significant decrease in serum HDL cholesterol. Simultaneous administration ofα-tocopherol with nickel sulfate improved LDL-cholesterol and HDLcholesterol level when compared with rats receiving nickel sulfate alone.The results indicate thatα-tocopherol is beneficial in preventing nickel-induced lipid profile alterations.

NiSO_(4)/OMMT复配体系协同膨胀阻燃环氧树脂的阻燃和抑烟性能

为降低环氧树脂的火灾危险性,以NiSO_(4)和有机蒙脱土(OMMT)复配体系作为协效剂用于增强膨胀阻燃环氧树脂的火安全性,通过氧指数测试仪、垂直燃烧测试仪、烟密度仪和锥形量热仪系统分析膨胀阻燃环氧树脂的阻燃和生烟性能。研究结果表明:单独添加NiSO_(4)或OMMT均能提高膨胀阻燃环氧树脂的阻燃、抑烟、热稳定性和成炭性能,将二者复配使用则表现出更优异的协效作用;当NiSO_(4)和OMMT以1∶1的质量比复配使用时,膨胀阻燃环氧树脂的极限氧指数(LOI)达到31.1%并通过UL94 V-0级测试,800℃时的残余质量达到22.6%,总释放热和总生烟量相比于纯环氧树脂分别降低56.0%,65.8%;炭层分析表明,NiSO_(4)和OMMT复配体系能提高试样燃烧后炭层的交联密度,增强炭层的致密性和隔热性,达到协效阻燃和抑烟的效果。研究结果可为提高环氧树脂基产品的阻燃和抑烟性能提供参考与借鉴。