扩散渗析法对镍电积阳极液酸盐分离应用研究

针对含酸电积阳极液需在生产过程中平衡中和的生产实际,采用扩散渗析膜法对电积阳极液中的硫酸和硫酸镍溶液进行了分离研究。结果表明,通过扩散渗析,硫酸回收率在80%以上,镍的截留率在90%以上。在接受液分别为自来水和碳酸镍上清液的情况下,扩散渗析法能有效回收硫酸同时对镍离子具有较好的拦截性能。     

氯气浸出-电积工艺从铜渣中提取镍

研究通过氯气浸出-净化-不溶阳极电积法生产电镍的工艺过程.结果表明,镍和铜的浸出率分别为99.3%和98.5%,经过净化的授出液用400 A·m-2的电流密度不溶阳极电积,所得电镍纯度可达99.935%,电积过程的阴极电流效率为98%.在电积过程中氯气可以处理回收并返回作为浸出剂,使生产成本及环境污染降低.     

水淬金属化高冰镍选择性浸出镍钴过程中的相转变

<正> 前言高冰镍湿法冶金自五十年代兴起后又有新发展,由高锍磨浮-硫化镍阳极电解-阳极液净化流程,进展为金属化高冰镍水淬常压或加压浸出-黑镍除钴-不溶阳极电积铜及镍的工艺流程。吸取国内外各流程的优点,我院采取了水淬金属化高冰镍用硫酸硫酸铜溶液     

扩散渗析法回收高砷污酸中的硫酸

在实验室条件下,考察分析了静态扩散渗析中砷(Ⅲ)和硫酸的扩散渗析现象及通量、砷(Ⅲ)与硫酸之间的相互影响关系。结果表明,在3%～15%硫酸和1～3g/L砷(Ⅲ)的浓度范围内,砷(Ⅲ)显示为定量扩散的特征,硫酸浓度对实验结果影响较k·CAs·V/S砷(Ⅲ)泄漏;硫酸渗析系数随砷(Ⅲ)浓度增加而减少约5%～25%。综合实验数据,在24h静态扩散渗析基本稳定时,硫酸的平均回收率约50%,砷(Ⅲ)的平均泄漏率低于15%,可为实际工业提供指导借鉴。     

膜法回收稀土冶金过程中废酸的可行性研究

对用减压膜蒸馏法及扩散渗析法回收稀土冶金过程中的废酸(盐酸及硫酸)的可行性进行了研究。结果表明, 减压膜蒸馏能回收稀土氯化物溶液中高达80%的游离盐酸, 且由于对稀土离子的截留率一般大于98%, 在减压侧能回收得到较纯的盐酸溶液; 扩散渗析法也能有效回收硫酸稀土溶液中的硫酸, 在实际操作时控制硫酸回收率为70%～80%, 水料流量比在1左右较为合适; 采用减压膜蒸馏与扩散渗析的集成膜法回收硫酸稀土溶液中的硫酸, 对稀土离子的截留率基本无影响, 但增大了回收液的硫酸浓度, 大大减少了扩散渗析的处理量, 而浓缩倍数越大效果越明显。     

扩散渗析法回收高砷污酸中硫酸的实验研究

扩散渗析法回收高砷污酸中硫酸具有良好的市场前景。本文主要考察实验室条件下静态扩散渗析中砷（Ⅲ）和硫酸的扩散渗析现象及通量、砷（Ⅲ）与硫酸之间的相互影响关系,该研究成果可为实际工业提供指导借鉴。结果表明：在3-15 %硫酸和1-3 g/L砷（Ⅲ）的浓度范围内,砷（Ⅲ）显示为定量扩散的特征,硫酸浓度对实验结果影响较小,砷（Ⅲ）通量增加幅度与初始砷（Ⅲ）浓度增加幅度基本一致,建立关联公式： （k≈7.0）,可以采用此参数预估砷（Ⅲ）泄漏;硫酸渗析系数随砷（Ⅲ）浓度增加而减少约5~25 %。综合本文实验数据,在24h静态扩散渗析基本稳定时硫酸的平均回收率约50 %,砷（Ⅲ）的平均泄漏率低于15 %。     

渗析法从铀溶液中分离硫酸的初探

采用硫酸淋洗载铀树脂时,淋洗合格液中的硫酸浓度很高,扩散渗析可以用来分离回收其中大部分的硫酸,从而降低溶液的酸度,减少了沉淀产品的碱耗。通过初步试验,探讨了用离子交换扩散渗析膜有选择性地回收酸分离铀的机理及影响因素。     

基于响应面法优化同槽电积锰和二氧化锰工艺研究

针对目前生产锰和电解二氧化锰行业能耗大、污染严重的问题,设计了一种同槽电沉积锰和二氧化锰工艺,在提高阴阳极电流效率的同时使得能耗最低,达到节能降耗的目的。结合响应面法对阴极硫酸铵浓度、阳极硫酸浓度、中隔室硫酸浓度、温度四个因素与阴阳极电沉积效率之间的交互作用进行分析,得到二次回归拟合模型,确定同槽电积的最佳条件为：阴极硫酸铵浓度为107.11 g/L,阳极硫酸浓度投加量为2.8 mol/L,中隔室硫酸浓度为0.516%,温度为40.2℃。阴极电流效率可达到84.79%、阳极电流效率可达到68.43%。分析表明,硫酸铵和温度对阴极电流效率交互影响最大、硫酸浓度和温度对阳极电流效率交互影响最大。电沉积得到的金属锰沉积紧密。电解二氧化锰粒径均一,形貌良好。     

渗析法从铀溶液中分离硫酸的进一步探索

用硫酸淋洗载铀树脂所得的合格液，来考察在不同渗析条件下聚醚型阴离子交换膜的静态和动态行为，及影响渗析传质的有关因素。初步试验表明，扩散渗析可以用来分离回收其中大部分的硫酸，从而降低溶液的酸度，减少沉淀产品的碱耗。     

黑镍除钴工艺的研究

黑镍是镍的高价氢氧化物,具有强氧化剂特性,在除钴过程还能深度净化铜、铁、锰、砷等杂质,是镍钴分离的一种好方法。本文研究了黑镍用量、温度、ｐＨ、溶液中钴浓度及黑镍中Ｎｉ￣（３＋）含量对除钴速度的影响。半工业试验和新疆阜康镍冶炼厂的工业实践表明,黑镍除钴工艺应用在硫酸盐体系中是可行的,除钴后溶液作为不溶阳极电积镍的阴极液,生产出的电镍完全符合１号电镍标准。     

The effect of sodium sulphate on the hydrogen reduction process of nickel laterite ore

A series of nickel laterite ores with different calculated amounts of anhydrous sodium sulphate were prepared by physical blending or sodium sulphate solution impregnation. The reduction of the prepared nickel laterite ore by H₂ was carried out in a fluidised-bed reactor with provisions for temperature and agitation control, and the magnetic separation of the reduced ore was performed using a Davis tube magnetic separator. The mineralogical properties of the raw laterite ore, reduced ore and magnetic concentrate were characterised using ICP, TG–DSC, N₂ adsorption, X-ray diffraction and optical microscopy. The catalytic activity of sodium sulphate was also studied by using Hydrogen temperature-programed reduction. The experimental results indicate that Na₂SO₄ could overcome the kinetic problems faced by the laterite ore and that it exhibited noticeable catalytic activity only if the temperature reached at least 750 °C. This high temperature accelerated the crystal phase transition of the silicate minerals and increased the utilisation of H₂. In comparing the results from the two different methods for adding Na₂SO₄, the nickel content and recovery of the magnetic concentrate were increased by using the impregnation method rather than the physical blending method and the increasing amount of sodium sulphate assisted in the further beneficiation of nickel. The partial pressure of H₂ and the reducing time also affected the reduction process of the iron oxides. The results of the microscopic study indicated that the formation of a Fe–S solid solution, which was derived from the SO₂ sulphide reduction of FeO, was conducive to mass transfer and accelerated the coalescence of metallic ferronickel particles. For the nickel laterite ore, under the synergistic effect of sodium sulphate and hydrogen, a nickel content and nickel recovery of 6.38% and 91.07% were obtained, respectively, with high product selectivity.     

Atmospheric leaching characteristics of nickel and iron in limonitic laterite with sulfuric acid in the presence of sodium sulfite

Atmospheric leaching of nickel from limonitic laterite ores is regarded as a promising approach for nickel production, despite its low nickel recovery and slower leaching rate than high pressure acid leaching. Sulfur dioxide can enhance the sulfuric acid leaching of laterite, but its behavior for enhancing atmospheric sulfuric acid leaching was uncertain due to SO₂ losses and emission. In this study, sodium sulfite was used as a substitute for SO₂ gas in the leaching and the sulfuric acid leaching characteristics of Ni and Fe from a limonitic laterite in the presence of sodium sulfite were investigated. A linear correlation exists between the extraction of Ni and Fe, indicating the difficulty in selective leaching of Ni over Fe. Most nickel is isomorphically substituted within the goethite and it is difficult to dissolve in a high oxidation–reduction potential solution environment, resulting in a low nickel recovery. SO₂(aq) generated from the reaction of sodium sulfite in sulfuric acid solution, lowers the potential for the reducing reaction of FeOOH to give Fe²⁺, accelerating the iron extraction and nickel liberation from goethite.     

Development of a clean bioelectrochemical process for leaching of ocean manganese nodules

Through the application of negative reduction potential significant reduction of manganic and iron oxides in the ocean manganese nodules can be achieved, liberating the occluded copper, nickel and cobalt for easy dissolution in an acid medium. Electroleaching and electrobioleaching of ocean manganese nodules in the presence of Thiobacillus ferrooxidans and Thiobacillus thiooxidans at the above negative applied dc potentials resulted in significant dissolution of copper, nickel and cobalt in 1 M H₂SO₄. The role of galvanic interactions in the bioleaching of ocean manganese nodules in the presence of T. thiooxidans is also discussed.     

Purification of rare earth elements from monazite sulphuric acid leach liquor and the production of high-purity ceric oxide

The present work describes the development of an efficient and relatively simple process to obtain high grade CeO₂ from sulphuric acid leach liquor. The liquor was obtained through acid digestion of monazite. The steps investigated in the process for obtaining ceric oxide were: (i) purification of the RE elements through their precipitation as rare earth and sodium double sulphate (NaRE(SO₄)₂·xH₂O), (ii) NaRE(SO₄)₂·xH₂O conversion into RE-hydroxide (RE(OH)₃) through metathetic reaction and (iii) recovery of cerium and (iv) purification of cerium from the mixture of ceric hydroxide and manganese dioxide precipitate through dissolution of the solid with HCl and precipitation of the cerium through the addition of oxalic acid (H₂C₂O₄) or ammonium hydroxide (NH₄OH) solution. The X-ray diffraction spectra of the double sulphate obtained indicated the presence of monohydrated double sulphate. X-ray diffraction and chemical analysis indicated that the precipitation should be carried out at 70 °C and at 1.1 times the stoichiometric ratio of NaOH. An excess of 30% of KMnO₄ was necessary to separate cerium from the other RE elements. Both oxalic acid and ammonium hydroxide proved efficient in the precipitation of cerium from the mixture of Ce/Mn obtained in the cerium separation. Following purification, calcinated products were obtained, assaying between 99% and 99.5% CeO₂. The cerium recovery yield was greater than 98%.     

Uranium recovery from strong acidic solutions by solvent extraction with Cyanex 923 and a modifier

Uranium stripping with strong acid solution is always highly desired due to its simple operation and less pollution. However, intensive acid neutralisation for uranium precipitation in the subsequent step limited its application. A new solvent extraction process has been developed to transfer uranium from strong to weak sulphuric acid solutions suitable for uranium precipitation without intensive neutralisation. An organic system consisting of 10% Cyanex 923 and 10% isodecanol as the modifier in ShellSol D70 was optimised for the process. It was found that uranium was extracted efficiently from 4 to 6 M H₂SO₄ solutions with the organic system, and it could be efficiently stripped with 0.2–0.5 M H₂SO₄ solutions. Both extraction and stripping kinetics of uranium were very fast, reaching the equilibrium within 0.5 min. Temperature between 30 and 60 °C has slight effect on uranium extraction and stripping. Four theoretical stages could effectively extract more than 98% uranium from a solution containing 17.5 g/L U and 6.0 M H₂SO₄ at an A/O ratio of 1:1.5, and it could generate a loaded organic solution containing about 12 g/L U. More than 99% U could be stripped from the loaded organic solution containing 14.6 g/L U with 0.5 M H₂SO₄ using five stages at an A/O ratio of 1:3. As a result, the loaded strip liquor containing more than 40 g/L U would be obtained which is suitable for uranium recovery by precipitation using hydrogen peroxide. A conceptual process has been proposed for uranium transfer from strong to weak sulphuric acid solutions for its recovery.     

Oxidation of Fe(II) in a synthetic nickel laterite leach liquor with SO2/air

Under specific controlled conditions, the addition of SO₂ to oxygen or air produces the peroxy-monosulphate free radical in solution, which is a stronger oxidant than oxygen alone. In this study, the practical strategies required to optimise the oxidation of Fe(II) with SO₂/air was investigated at 75 °C as part of a process to remove iron as Fe(III) oxides from a synthetic nickel laterite high pressure acid leach solution containing 5 g/L Fe(II), 1 g/L Fe(III), 8 g/L Ni, 30 g/L Mg in sea water at pH about 2. The rate of Fe(II) oxidation was optimised in the pH range of 1.2–2.0 with respect to SO₂/air ratio and gas flow rates for minimum production of H₂SO₄ and maximum utilisation of SO₂. In order to minimise the air flow rates into the reactor vessel, the maximum rate of SO₂ addition that could be employed with air was established whilst maintaining oxidising conditions. The results provide strategies for commercial applications of the SO₂/air oxidising system and indicate important factors for reactor design.     

鄂西某高磷鲕状赤铁矿磁化焙烧及浸出除磷试验

针对鄂西某高磷鲕状赤铁矿(铁品位43.50%),在实验室条件下采用磁化焙烧—磁选工艺获取铁精矿,并对该铁精矿进行酸浸、生物浸出除磷试验。研究结果表明,在焙烧温度850℃,焙烧时间25min,还原剂用量为矿石质量的5%,磨矿时间4min,磁场强度120kA/m条件下,得到铁精矿铁品位为54.92%,铁回收率为86.78%,P含量为0.83%;酸浸试验中矿浆浓度2%,分别用0.1mol/L的H2SO4,HNO3,HCl,草酸(C2H2O4),柠檬酸(C6H8O7)除磷,其中H2SO4除磷提铁效果最佳,铁精矿品位为57.98%,回收率为96.47%,除磷率为95.30%;生物浸出试验中矿浆浓度2%,用嗜酸氧化亚铁硫杆菌(At.f菌)对铁精矿作用后,磷含量为0.23%,用黑曲霉菌滤液对铁精矿作用后,磷含量为0.20%。     

Recovery of copper,nickel and cobalt from acidic pressure leaching solutions of low-grade sulfide flotation concentrates

Recovery of copper, nickel and cobalt from the acidic pressure leaching solutions of Jinbaoshan (YN Province, PRC) low-grade sulfide flotation concentrates was investigated. The proposed technique includes four major steps: (1) the acidity adjustment of the acidic pressure leaching solutions; (2) solvent extraction (SX) separation of copper by organic reagent XD5640, and then stripped from the loaded organic phase by H₂SO₄ solution for copper recovery; then (3) iron in raffinates after copper extracting is selectively removed by high-temperature hydrolysis precipitation in an autoclave; and lastly (4) nickel and cobalt are selectively precipitated by Na₂S from the final solutions after removing iron. The experimental results for treating 1 L acidic leaching solutions per batch by this new technique were reported, and some evaluation and further comparisons with previous investigations were also carried out. It was reported that the total percent recovery of Cu could reach 95% or more, and that of Ni and Co were all more than 99%. In the processing, the percent removal of impurities, such as Fe, Mg and Ca, were all also near to 99%.     

Extraction of titanium (IV) from acidic media by tri-n-butyl phosphate in kerosene

The extraction of titanium (IV) from sulfate, and nitrate solutions has been studied using tri-n-butyl phosphate (TBP) in kerosene. Extraction of titanium was affected by acid concentration over the range of 0.5–4 mol L^?1. The titanium distribution coefficient reached a minimum between 1 and 2 mol L^?1 acid for both sulfate and nitrate solutions. Third phase formation was observed in the extraction of titanium from acidic media at all condition tested. At the next stage, the stripping of titanium was studied using H₂SO₄, H₂SO₄ + H₂O₂ and Na₂CO₃. The kinetics of the stripping were very slow for H₂SO₄. The use of complex forming stripping agents (H₂SO₄ + H₂O₂) and Na₂CO₃ significantly improved the kinetics of stripping. About 98% recovery was achieved by extracting titanium from an aqueous nitrate solution using TBP and stripping with sodium carbonate.     

Acid leaching of metals from deep-sea manganese nodules – A critical review of fundamentals and applications

The mass% metal composition of deep sea nodules ranges from 10–28% Mn, 4–16% Fe, 0.3–1.6% Ni, 0.02–0.4% Co, and 0.1–1.8% Cu in mixed oxide matrices with alumina and silica. The concentrations of base metal ions in sea water of pH ∼ 8 of the order 10⁻³–10² nmol/kg are shown to be dependent on the solubility products (K_SP) of carbonate sediments. Cations of higher softness have higher pK_SP and lower solubility. Previously reported leach results of nodules in H₂SO₄ and HCl under atmospheric pressure and temperatures in the range 30–90 °C and in the absence or presence of SO₂, Na₂SO₃, NaCl and CaCl₂ are used in the present study to compare, contrast and rationalise the leaching behaviour of metal values. Leach efficiency of metals increases with increasing acid concentration, and Cu(II) and Zn(II) follow the same trend in HCl. Potential–pH diagrams of base metal oxides show a higher stability of mixed metal oxides such as ferrites, magnetite and manganite, which causes partial dissolution of high-valent oxides in the absence of reducing agents. Application of a shrinking core kinetic model in both H₂SO₄ and HCl media predicts a proton diffusivity of ∼ 10⁻¹¹ cm² s⁻¹ for the dissolution of Ni from nodules. This value is of the same order as D_H⁺ for the high pressure acid leaching of Ni from limonitic laterite. A linear correlation between leaching efficiencies of Fe and Ni appears to be a result of co-dissolution of these metals from NiO·Fe₂O₃ or NiFeOOH. The first order dependence of initial dissolution rates of Cu(II) with respect to H⁺ concentration in H₂SO₄, and the beneficial effect of background chloride ions, suggests a dissolution mechanism: CuO → Cu(OH)Cl_ads/aq → CuSO₄. The Cu(II) ions in solution can also affect Ni(II) dissolution from oxide by cation exchange mechanism. The presence of SO₂ or Na₂SO₃ as reducing agents facilitates the acid leaching of high-valent oxides of Mn and Co and other metals incorporated in the mixed oxide matrix. Whilst Fe(II) ions formed during the reductive leaching of Fe(III)-oxides accelerate the dissolution of Mn(III)/(IV) oxides, the resultant Mn(II) ions accelerate the dissolution of high-valent Co-oxides. Leaching efficiency in HCl increases with temperature. As for the SO₂/H₂O system thermodynamic calculations predict a decrease in concentration of H⁺ and at high temperatures, which retards leaching efficiency. The SO₂/H₂O/air leach system enhances metal dissolution due to the production of H₂SO₄ via the transition metal catalysed oxidation of SO₂ to H₂SO₄.