Aluminum extraction from aluminum industrial wastes

Aluminum dross tailings, an industrial waste from the Egyptian Aluminum Company (Egyptalum), was used to produce two types of alums: aluminum sulfate alum (Al₂(SO₄)₃·12H₂O) and ammonium aluminum alum {(NH₄)₂SO₄AL₂ (SO₄)₃·24H₂O}. This was carried out in two processes. The first involves leaching the impurities using diluted H₂SO₄ with different solid/liquid ratios at different temperatures to dissolve the impurities present in the starting material in the form of aluminum sulfates. The second process is the extraction of aluminum (as aluminum sulfate) from the purified aluminum dross tailings thus produced. This was carried out in an autoclave. The effects of temperature, time of reaction, and acid concentration on pressure leaching and extraction processes were studied in order to specify the optimum conditions to be applied in the bench scale production as well as the kinetics of leaching process.     

The hydrometallurgical extraction of lithium from egyptian montmorillonite-type clay

The processing of El-Fayoum montmorillonite-type clay deposits is attained through leaching with commercial sulfuric acid using a ball-mill-type autoclave. This process yields lithium sulfate, which can be used either for the production of lithium carbonate or to produce lithium metal. The effects of temperature, grain size, and sulfuric acid concentration and leaching on lithium recovery as well as the kinetics of the leaching process have been studied.     

Hydrometallurgically treating antimony-bearing industrial wastes

In many instances, by-products or wastes containing antimony are generated during metallurgical processes. Although these materials pose environmental, recycling, and marketing challenges worldwide, the use of antimony hydrometallurgical leaching principles and technologies may provide a remedy. This paper outlines techniques for treating antimony-containing wastes and offers examples of applications for those wastes and by-products. For more information, contact C.G. Anderson, Montana Tech of the University of Montana, the Center for Advanced Mineral and Metallurgical Processing, Room 221 ELC Building, Butte, Montana 59701; telephone/fax (406) 496-4794; e-mail: CAnderson@mtech.edu.     

Recovering metals from hydrometallurgical residues

Experimental results and a method for recovering Cu, Zn, Cd, and Co from a solid hydrometallurgical residue are presented. A series of leaching, oxidation, and solvent extraction stages are the keys to the process.     

从铜冶炼烟气酸洗液中分离富集铼

铜冶炼烟气酸洗液经D296阴离子交换树脂吸附后,再依次采用氨水解吸Sb,NaOH和酒石酸混合溶液解吸Bi,NH₄SCN溶液解吸Re,实现Re/Sb/Bi的分步解吸并获得铼富集液。结果表明：酸洗液电位对Re、Sb、Bi吸附率没有明显影响,适宜的酸洗液H₂SO₄浓度为43.81 g·L^-1,Re、Sb、Bi吸附率分别为100%、6.55%和89.05%;D296树脂吸附Re的穿透容量和饱和容量分别为1.308和1.773 g·L^-1,且树脂利用率为73.77%;先采用12.5%氨水解吸Sb,16%NaOH+140 g·L^-1酒石酸混合溶液解吸Bi,通过添加酒石酸可有效抑制Bi水解,再采用10%NH₄SCN溶液解吸Re,得到铼富集液,其Cu、As、Sb、Bi浓度均降至1 mg·L^-1以下,且使酸洗液中Re富集了4倍。     

The cuprex metal extraction process: Recovering copper from sulfide ores

The Cuprex? metal extraction process produces cathode-grade copper using a hydrometallurgical process based on chloride leaching of sulfide ore concentrates. The process incorporates several novel steps to overcome the major problems associated with earlier chloride-based processes, including mild leaching conditions using ferric chloride as leachant and solvent extraction of copper usinga novel reagent. This produces a highly concentrated cupric chloride electrolyte from which cathode-grade copper is electrowon in the Metclor cell. The technical viability and robustness of the core technology have been proven in a series of large-scale pilot trials. More recent work has concentrated on supplementary processes to convert the copper powder product to an article of commerce and to recover valuable by-products. A fully integrated scheme is now being developed with updated cost estimates.     

Recovery of rhenium from molybdenum and copper concentrates during the Looping Sulfide Oxidation process

Rhenium is recovered during pyrometallurgical processing of molybdenum sulfide and copper sulfide ores; the traditional technology involves removing rhenium(VII) oxide, Re₂O₇, from the sulfurous gas phase generated during multiple hearth roasting (in molybdenum processing) and smelting (in copper processing). A new technology platform called Looping Sulfide Oxidation (LSO) has been proposed to produce molybdenum and copper using alternative process chemistries. A detailed thermodynamic study of the reaction conditions used in LSO process indicates that rhenium recovery is possible at higher rates than currently realized in the industry. Conditions at which Re₂O₇ is reduced to rhenium metal by S₂ have been identified and key process conditions are outlined to maximize performance of the LSO scheme and rhenium recovery.     

The industrial separation of copper and arsenic as sulfides

At the Kennecott Utah copper smelter in Magna, Utah, bleed streams from the refinery tankhouse and precious-metals plant are combined with smelter weak acid and electrostatic precipitator dust to produce leach solutions containing copper and impurities. Copper and arsenic are precipitated from the solutions as sulfides in a two-stage continuous process that enables excess arsenic to be removed from the circuit and routed to hazardous waste disposal as a highly concentrated material. For more information, contact P.J. Gabb, Rio Tinto Technical Services, P.O. Box 50, Castlemead, Lower Castle Street, Bristol BS99 7YR, United Kingdom; telephone 44-117-927-6407; fax 44-117-927-3317; e-mail phil.gabb@riotinto.com.     

熔炼低品位电子废料中铜的湿法冶金选择性回收

比较从低品位电工电子废料中选择性回收铜的3种湿法冶金方法。首先将废料熔炼成Cu?Zn?Sn?Ag合金,并采用SEM?EDS和XRD进行表征。对合金进行阳极溶解,首先采用氨溶液和硫酸溶液对合金进行电沉积或在氨?硫酸铵溶液中浸出,然后进行电沉积铜。实现了各种金属分离,Pb、Ag 和Sn等沉积在阳极泥中,而铜则转移至电解液中并在阴极上还原析出。最佳的处理条件为在硫酸溶液中浸出,获得的最终产品为高纯Cu(99%),电流效率为90%。采用氨浸出可使Cu离子富集在电解液中,利于后续的电沉积,但是自发溶解的速率较低。在氨?硫酸铵溶液中进行阳极溶解不利于各种金属在阳极泥、电解液和阴极沉积物进行分离。     

Optimization of brine leaching of metals from hydrometallurgical residue

An orthogonal array,L16(45),was used to examine the effects of four parameters,including NaCl concentration,H2SO4 concentration,temperature and pulp density,on the recovery of Cu,In,Pb and Zn from a hydrometallurgical residue via brine leaching.The results show that temperature of leaching solution has a significant effect on the recovery of Cu,In and Zn,while H2SO4 concentration has an obvious influence on these metals extraction.Both pulp density and NaCl concentration significantly affect Pb extraction.Based on the orthogonal array experiments,the optimum conditions for the extraction of Cu,In,Pb and Zn from hydrometallurgical residue are NaCl concentration of 250 g/L,H2SO4 concentration of 1.00 mol/L,temperature of 85℃,and pulp density of 100 g/L.After 1 h of treatment at these optimum conditions,over 91% of the metals are extracted from the residue.Brine leaching is therefore suitable for the recovery of metals from hydrometallurgical residues.     

Processing industrial wastes with the liquid-phase reduction romelt process

The Romelt technology for liquid-phase reduction has been developed for processing metallurgical wastes containing nonferrousmetal components. Thermodynamic calculations were made to investigate the behavior of silver, copper, zinc, manganese, vanadium, chrome, and silicon when reduced from the slag melt into the metallic solution containing iron. The process can be applied to all types of iron-bearing wastes, including electric arc furnace dust. The distribution of elements between the phases can be controlled by adjusting the slag bath temperature. Experiments at a pilot Romelt plant proved the possibility of recovering the metallurgical wastes and obtaining iron. For more information, contact Y. Pokhvisnev, Moscow State Institute of Steel and Alloys, Leninsky pr. 4, Moscow 117936, Russia; fax 095955-0019; e-mail pokh@aha.ru.     

The outocompact SX approach to copper solvent extraction

Since 1977, Outokumpu has been developing a wide variety of solvent extraction applications focusing on both equipment and process development. The work, a response to an increasing demand for lower operational costs as well as higher investment cost savings, is reviewed in this article. For more information, contact R. Kuusisto, Outokumpu Technology, Riihitontuntie 7 E, Espoo 02200, Finland; +358-9-4211; fax +358-9-421-2434; e-mail raimo.kuusisto@outokumpu.com.     

The pyro- and hydrometallurgical processing of uranium-containing waste

As large amounts of uranium-containing (both high and low-level) waste are generated from activities such as fuel fabrication, fuel reprocessing, and R&D, concern is growing over the safe disposal of these radioactive materials. Over the past few decades, numerous disposal options have been investigated, including pyrometallurgical high-temperature fusion/vitrification, hydrometallurgical processing, biological remediation, polymerization, clay back-filling, and zeolite adsorption. This paper reviews the techniques, thermodynamics, and kinetic aspects of processing uranium-containing waste. In particular, the removal of uranium waste by zeolite adsorption and mechanisms are discussed. In addition, the pyro- and hydrometallurgical conceptual flow sheet is proposed for the disposal of uranium-containing waste. For more information, contact R.G. Reddy, The University of Alabama, A-129 Bevill, Tuscaloosa, Alabama 35487-0202; phone: (205) 348-4246; fax: (205) 348-2164; e-mail: rreddy@coe.eng.ua.edu.     

水钴矿中选择性提取铜和钴的新工艺

针对某水钴矿的特点,采取还原酸浸旋流电积新工艺选择性提取其中的铜和钴。系统考察初始硫酸浓度、温度、时间、Na2SO3用量、液固比等因素的影响,确定浸出最佳条件如下:初始硫酸浓度为75g/L,Na2SO3用量为7%,液固比L/S=4 mg/L,温度为70℃,时间为0.5 h。对浸出液进行了旋流电积提取铜和钴的探索实验研究,得到纯度分别为99.95%、99.97%的电积铜、钴产品,铜、钴的直收率分别达到98.23%和94.54%。     

Removing as from converter dust by a hydrometallurgical method

Research has been conducted at the Faculty of Metallurgy, Technical University, Kosice, to develop a hydrometallurgical method for removing arsenic from copper converter dust. The process consists of a selective leaching of the flue dust in which arsenic is dissolved in sodium-sulfide solution and then removed by precipitation methods using various agents: copper sulfate, a mixture of phosphoric acid with calcium hydroxide, calcium oxide, and ferrous or ferric sulfate. In principle, arsenic can be removed as a marketable product (copper arsenate for wood preservation) or as stable precipitate compounds suitable for safe landfill disposal under existing U.S. Environmental Protection Agency regulations. For more information, eontact E. Vircikova, Technical University, Faculty of Metallurgy, Letna 9, 04000 Kosice Slovakia; telephone 421-95-602-2703; fax 421-95-633-7048; e-mail vircik@hfnov.tuke.sk.