锌烟灰浸出液中铟、锗的提取

以锌烟灰硫酸化焙烧—浸出得到的浸出液为原料,采用P204萃铟、丹宁酸沉锗的方法实现了溶液中铟、锗的提取。以P204为萃取剂,盐酸溶液为反萃剂,铟的萃取率、反萃率均大于99%。铟萃余液用丹宁酸沉锗,最佳条件下的锗沉淀率大于99%。     

Nickel and cobalt precipitation from sulphate leach liquor using MgO pulp as neutralizing agent

The research work presented in this paper determined the conditions at which nickel and cobalt can be recovered, as easily filterable precipitates, from leach liquors, which are produced by sulphuric acid leaching of nickel oxide ores, at atmospheric pressure. More specifically, nickel and cobalt were precipitated as hydroxides at pH = 9, using MgO pulp as a neutralizing agent, by 99.9% and 99.0%, respectively. At this pH value, manganese, which was contained in the leach liquor, was precipitated having a concentration of about 3% in the final mixed precipitate. Statistical design and analysis of experiments were used in order to determine the main effects and interactions of the precipitation factors, which were the pH at equilibrium and the addition of seed material. The characterization of the produced mixed precipitate was carried out by X-ray diffraction, TG–DTA, scanning electron and optical microscopy and particle size distribution analyzer. The main mineralogical phases in the precipitate were theophrastite (Ni(OH)₂) and brucite (Mg(OH)₂). The microscopic observation revealed that the presence of brucite was, mainly, due to the un-reacted MgO pulp, during the precipitation process. This brucite content acted as seed material for nickel precipitation.     

泥矿和高品位精矿搅拌浸出工艺研究

对堆浸前矿石的破碎分级中的泥矿和高品位精矿进行了搅拌浸出工艺的实验室试验研究和现场验证试验。泥矿酸法搅拌浸出铀浸出率达到96%以上。高品位矿石碳酸盐含量高,酸法浸出铀浸出率可达99%以上,但是酸耗高;而碱法浸出高品位矿石时,在常温条件下浸出率不到70%,提高浸出温度可显著提高浸出率。使用压滤机进行固液分离是可行的,其矿石处理能力可达到155 kg/(m2.d),洗涤效率达99%以上。     

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%.     

新型抑制剂在稀土尾矿综合回收萤石重晶石中的应用

四川某稀土矿山选厂尾矿含泥量大,萤石、重晶石品位均很低,重晶石矿物粒度较细,难以综合回收利用。采用自主研发的抑制剂SDN作为重晶石抑制剂,经混合浮选-萤石重晶石分离工艺选别,可得到Ca F2品位为97.28%、回收率为80.33%的萤石精矿和Ba SO4品位为90.45%、回收率为75.98%的重晶石精矿。新型抑制剂SDN为离子型小分子药剂,不仅能有效抑制重晶石,实现萤石与重晶石高效分离,还能有效避免絮凝现象导致的回水黏度越来越大,有利于生产顺利进行。     

盐酸—三氯化铁选择性浸出含铋铜精矿分离铜铋

采用盐酸与六水合三氯化铁体系浸出含铋铜精矿分离铜铋,浸出液水解沉淀制备氯氧铋产品,水解后液可通过硫化沉淀回收其中的铜。结果表明,铜铋分离最佳浸出条件为HCl 2mol/L,每公斤矿所属FeCl_3·6H_2O量为320g,液固比3∶1,浸出温度70℃,浸出时间3h。此条件下,铋的浸出率大于95%,铜精矿含铋由2.97%降至0.2%,符合行业标准。浸出液经中和水解可得到含铋大于65%的氯氧铋产品。     

Extraction of cobalt(II) from an ammonium nitrate-containing leach liquor by an ammonium salt of di(2-ethylhexyl)phosphoric acid

A hydrometallurgical process that involves solvent extraction and selective precipitation has been used to selectively recover Co²⁺ from an aqueous filtrate containing mostly Co²⁺, NH₄⁺ and NO⁻₃ ions and trace amounts of Pt²⁺, Al³⁺ and Fe³⁺ ions. The effect of pH on the precipitation efficiencies of Al³⁺ and Fe³⁺ ions from the leach liquor was investigated. Solvent extraction exhibited good performance in terms of both Co²⁺ and Pt²⁺ ions extraction efficiency and phase separation when ammonium salt of di(2-ethylhexyl)phosphoric acid was used as an extractant in the presence of a tributylphosphate modifier. Cobalt was stripped from the organic phase with nitric acid to yield cobalt nitrate.     

Extraction of copper, nickel and cobalt from the leach liquor of manganese-bearing sea nodules using LIX 984N and ACORGA M5640

This paper describes a method, using sulfuric acid and activated charcoal for leaching Polymetallic sea nodules. Resulting leach solutions were examined for the extraction of copper, nickel and cobalt using LIX 984N and ACORGA M5640 in kerosene. After the removal of manganese and iron impurities from the leach liquor, copper and nickel were co-extracted leaving cobalt in the raffinate. The selective stripping of nickel and copper produces solutions rich in these metals, while regenerating the solvent for reuse.     

Selective leaching of arsenic and antimony from a tetrahedrite rich complex sulphide concentrate using alkaline sulphide solution

Removal of impurity elements in copper metallurgy is one of the major problems encountered today since pure copper ore reserves are becoming exhausted and the resources of unexploited ores often contain relatively high amounts of impurity elements like antimony, arsenic, mercury and bismuth, which need to be eliminated. The present work is aimed at pre-treating a tetrahedrite rich complex sulphide concentrate by selective dissolution of the impurities, therefore, upgrading it for pyrometallurgical processing. To accomplish this, dissolution of antimony and arsenic by an alkaline sulphide lixiviant from the concentrate were investigated. The lixiviant proved selective and effective to dissolve these impurity elements from the concentrate with good recoveries. Further investigations on the factors influencing the leaching efficiency of the lixiviant were studied. The parameters considered were sulphide ion and hydroxide ion concentrations, mineral particle size, reaction temperature and leaching time. Analysis of the leach residue indicates that copper content of tetrahedrite has transformed into copper sulphides with the average chemical formula Cu_1.64S. The grade and economic value of the concentrate were improved greatly after sulphide treatment, and therefore, suitable as a feedstock for smelting. The impurities have been reduced to low levels which are tolerable in the smelting furnace and consequently reduce both the treatment and environmental problem encountered when such concentrate is processed pyrometallurgically.     

Recovery of dissolved platinum group metals from copper sulphate leach solutions by precipitation

The pregnant leach solution produced in the final leaching stage of base metal refineries (BMRs) operated by platinum producers contains impurities such as selenium and tellurium as well as other precious metals (OPMs, which include Rh, Ru and Ir). The aim of this project was to propose operating conditions for a thio-urea precipitation process that would allow maximum OPM recovery and impurity precipitation from the leach solution with minimal copper and nickel co-precipitation. Experimental results illustrating the effects that operating temperature (80 °C and 160 °C), pressure (atmospheric pressure and seven bar), stirring rate (250 rpm and 500 rpm) and thio-urea quantity (200% and 320% excess) have on the precipitation behaviour are presented.Virtually all of the Rh contained in the solution was precipitated irrespective of the values of the process variables studied. The maximum percentage Ru and Ir precipitation achieved were 87% and 60%, respectively. Complete Se precipitation was observed at all process conditions, while Te precipitation increased as the operating temperature was increased. Increasing the reagent quantity and temperature did, however, also result in increased copper and nickel co-precipitation.Regression models were used to perform numerical analyses to determine suitable operating conditions. Predictions with this numerical approach suggested that precipitation with 200% excess thio-urea at a temperature of 80 °C and a pressure of 7 bar would yield 98% Rh, 75% Ru, and 48% Ir precipitation with less than 5% Cu and Ni co-precipitation; these results could be experimentally validated.     

电磁感应辊强磁选机分选锆英砂粗精矿运行参数分析与优化

电磁感应辊强磁选机具有磁场强度高(2.2 T)和磁场梯度大的特点,广泛应用于细粒非金属矿除铁及弱磁性金属矿的干法分选作业。电磁感应辊强磁选机的运行参数对分选效果有重要影响,对电磁感应辊强磁选机分选锆英砂粗精矿运行参数进行试验研究。在单因素试验基础之上确定磁场强度、分选辊转速和分矿板位置三个影响因素的取值范围并进行多因素试验。采用响应面法进行影响因素和分选效果的的多元回归拟合分析,建立目标函数精砂ZrHfO₂含量(Y₁)、铁含量(Y₂)和产率(Y₃)分别与磁场强度(A)、分选辊转速(B)、分矿板位置(C)三个影响因素的二次多项式回归模型,分析了模型的有效性,确定影响因素单项(A、B、C)及交叉项(AB、AC、BC)对分选效果影响权重顺序。针对优选值附近区域,确定了回归模型的最优运行参数条件,进行了分选试验验证。     

Recovery of zinc from an industrial zinc leach residue by solvent extraction using D2EHPA

A hydrometallurgical treatment involving solvent extraction of zinc using di-2-ethylhexyl phosphoric acid (D2EHPA) has been investigated to recover zinc from an industrial leach residue. The residue was leached with sulfuric acid producing leach liquor which was subjected to solvent extraction for enrichment of zinc and removal of impurities. Operating variables, such as pH, D2EHPA concentration, temperature, aqueous/organic (A/O) phase ratio, tri-butyl phosphate (TBP) concentration and sodium sulfate (Na₂SO₄) concentration in aqueous phase were studied. Practically, all zinc was extracted from the aqueous solution at pH 2.5 with 20% w/w D2EHPA in kerosene. Increasing either TBP concentration up to 5%, or Na₂SO₄ concentration up to 0.2 M, increased the zinc extraction. Zinc could be extracted at one theoretical stage at A/O of 1/1, as calculated by McCabe–Thiele method.     

Selective adsorption of precious metals from hydrochloric acid solutions using porous carbon prepared from barley straw and rice husk

Porous carbon was prepared by carbonization from agro-waste such as rice husk and barley straw to evaluate the adsorption of precious and base metals from metal solutions. The effects of hydrochloric acid concentration, metal ion concentration, and contact time on adsorption were examined. Rice husk carbon was found to be highly selective for Au(III) and inert to Pt(IV), Pd(II) and other base metals. Barley straw carbon adsorbed these three precious metal ions, but was inert to base metal ions such as Cu(II), Fe(III) and Ni(II). The maximum adsorption capacity of rice husk carbon for Au(III) was 0.76 mol/kg and the maximum adsorption capacity of barley straw carbon for Au(III), Pt(IV) and Pd(II) was 1.47, 0.39 and 0.64 mol/kg, respectively. The effectiveness of recovery of precious metals from industrial solution was also tested and barley straw carbon was found to be highly efficient and selective for the targeted metal ions in the presence of excess of other metal ions. Rice husk and barley straw carbon are thus potential alternatives to commercially available activated carbon as they have high selectivity and are efficient with low production costs.     

Removal of arsenic and sulfur from a refractory gold concentrate by microwave heating

In this study the removal of sulfur and arsenic from a refractory flotation gold concentrate by microwave heating was investigated. The results showed that cooling pattern of the heated products, heating time, temperature and atmosphere had significant effect on the removal of sulfur and arsenic.     

Preparation of high-purity and low-sulphur graphite from Woxna fine graphite concentrate by alkali roasting

An alkali roasting process, which consists of roasting with caustic soda, water washing and sulphuric acid leaching, has been found to be an effective method for graphite purification even at low roasting temperature. With this process, a flotation fine concentrate containing 87–88% carbon could be purified to about 99.4% carbon when roasted with 25% NaOH at 250 °C and leached by 10% H₂SO₄ solution at room temperature. In addition to the successful removal of silicate impurities, the process was also found to be effective to eliminate sulphide impurities. For instance, the sulphur content in the end product could be reduced to below 0.05% from 0.6% by the process. Furthermore, the consumption of NaOH can be lowered by using high-grade feed. When using a feed of 95.9% carbon (upgraded by flotation), the NaOH concentration could be reduced to 10% from 25% while the product purity could reach the same purity level of over 99%.     

Microfluidic solvent extraction of platinum and palladium from a chloride leach solution using Alamine 336

Microfluidic solvent extraction (μSX) of platinum and palladium from chloride leach solution using Alamine 336 had been conducted. The leach solution was produced by leaching of spent automotive catalysts. A microfluidic Y–Y channel embedded in a Pyrex™ microchip was used as the extraction system. Platinum and palladium extractions (>99%) occurred at μSX contact time as fast as 1 s with subsequent marginal extraction efficiency increases for longer contact times with comparable extraction performance to that of bulk SX. Findings from this preliminary study are useful in initiating a new metallurgical technique in the field of recovering precious (high-value) metals present in low concentrations which are otherwise not technically amenable (or economically viable) to extraction using current conventional methods.     

脆硫锑铅矿与磁黄铁矿在石灰介质中的浮选分离研究

研究了磁黄铁矿和脆硫锑铅矿在捕收剂存在时的浮选行为, 发现二者在pH=2 ～ 12 的范围内均有良好的可浮性。选用工业常用调整剂石灰进行了选择性分离浮选试验。结果表明, 石灰不能很好地分离脆硫锑铅矿和磁黄铁矿。通过红外光谱分析测定了矿物表面与药剂的吸附产物, 进行了机理探讨。     

Recovery of nickel and cobalt from laterite leach tailings through resin-in-pulp scavenging and selective ammoniacal elution

In the hydrometallurgical processing of nickel laterite ore, a significant amount of dissolved nickel and cobalt can be lost to neutralized tailings slurry during counter current decantation. Resin-in-pulp (RIP) scavenging using ion exchange resin functionalized with iminodiacetic acid (IDA) has been proposed as an effective way to recover lost metal value. However, the tendency of this resin to co-load impurities makes integration of metal value back into the plant challenging. In this paper, the application of bis-picolylamine functionalized resin to RIP scavenging is explored. Both types of resin load the valuable metals effectively but bis-picolylamine functionalized resin has a much lower affinity for unwanted impurities. After loading, selective elution of nickel and cobalt from the new resin was carried out using an ammonia based eluent. The resultant eluate was high in nickel and cobalt with ppm levels of impurities, making it appropriate for downstream integration in existing nickel/cobalt refineries.     

煅烧酸浸铁矿石制备硫酸铁的研究

利用铁矿石为主要原料,通过煅烧酸浸法制备出硫酸铁,确定了合理的生产工艺和操作条件.结果表明,当煅烧温度为800℃,煅烧时间为2h,硫酸浓度为5mol/L,酸浸时间为3h以及液固比(硫酸与铁矿石质量比)为6∶1时,铁的浸出率最高.此方法为硫酸铁的生产提供了一条原料廉价的工艺路线,达到了以废治废的目的,取得了良好的经济效益、社会效益和环境效益.