清洁的炼铜工艺

本文简要介绍了世界上各种处理硫化铜矿的新型湿法炼铜工艺的发展现状及其日益看好的应用价值。     

Oxynitride glasses—An overview

The theory and practice of oxynitride glass synthesis and property evaluation came into effect since late 70’s. Its importance lies in the fact of its formation at the grain-boundary of synthesized silicon-nitride ceramics with additives. Earlier, heating an oxide glass with NH₃ and/or N₂ was the route to obtain oxynitride glass. Later on greater amount of nitrogen retention was made possible using AlN or Si₃N₄ as batch material. Silicate, borate and phosphate systems were studied in isolation or in conjugation. Melting temperature of such glasses varied from 1500–1800° C. Different technological developments regarding furnace atmosphere, temperature, compositions etc have been discussed towards a successful synthesis with a thermodynamic approach. Nitrogen content in glass as high as 36.8 eq% has been reported by the application of an overpressure of 30 atm N₂. Different physical and chemical properties have been discussed in relation to nitrogen content in glass. Structural aspects have been considered with respect to XPS and IR spectroscopic studies. Finally some points have been highlighted towards some potential applications     

某离子型稀土矿采矿活动对地下水的影响分析

离子型稀土原地浸矿工艺原理是用硫酸铵作为浸矿液,把呈吸附态的稀土离子交换浸出并回收稀土元素。该工艺对环境的影响主要是由于浸矿液的渗漏而造成地下水中氨氮浓度增加。针对该种工艺,如何采取有效措施保护地下水质量意义重大。以某稀土矿地下水环境影响评价为例,通过设置两种情景模式,应用数值法来证明地下水水力截获是原地浸矿区地下水质量保护的有效措施。     

多金属硫化矿综合回收进展

介绍了近年来多金属硫化矿浮选的进展、浮选工艺和浮选药剂的现状及发展,总结了国内多金属硫化矿混合精矿化学法处理工艺的研究进展。对各种工艺进行了简单介绍和评论,并对其发展趋势进行了展望。     

Recovery of Mo from Ni-Mo ore leach solution with carrier co-precipitation method

In this paper, “nascent” Fe(OH)₃ as carrier precipitation and NaHCO₃ as buffer agent were used to extract molybdenum from the complex Ni-Mo ore leach solution. The effects of different variables on the molybdenum extraction, such as the dosage of FeCl₃ and NaHCO₃ and the reaction temperature and time, were studied. The results showed that over 99% of molybdenum were extracted in 2 h at 25 ± 1 °C under the conditions of mole ratio of Fe³⁺/Mo 2.2-2.5 and mass ratio of NaHCO₃/Mo 0.7-1.5. About 92% of Mo in the Fe(OH)₃ precipitation can be leached by NH₃⋅H₂O to prepare the ammonium molybdate solution with about 100 g/L Mo. After treating with NH₃⋅H₂O, the Fe(OH)₃ precipitation was dissolved with HCl to obtain the FeCl₃ solution (FeCl₃ 500 g/L) which can be reused for the next round of experiments.     

Hydroceramics,a "new" cementitious waste form material for U.S. defense-type reprocessing waste

A "hydroceramic" (HC) is a concrete which possesses mineralogy similar to the zeolitized rock indigenous to the USA's current "basis" high level radioactive waste (HLW) repository site, Yucca Mountain (YM). It is made by curing a mixture of inorganic waste, calcined clay, vermiculite, Na₂S, NaOH, plus water under hydrothermal conditions. The product differs from conventional Portland cement and/or slag-based concretes ("grouts") in that it is primarily comprised of alkali aluminosilicate "cage minerals" (cancrinites, sodalites, and zeolites)rather than hydrated calcium silicates (C-S-H in cement-chemistry shorthand). Consequently it microencapsulates individual salt molecules thereby rendering them less leachable than they are from conventional grouts. A fundamental difference between the formulations of HCs and radwaste-type glasses is that the latter contain insufficient aluminum to form insoluble minerals with all of the alkali metals in them. This means that the imposition of worst-case "repository failure" (hydrothermal) conditions would cause a substantial fraction of such glasses to alter to water-soluble forms. Since the same conditions tend to reduce the solubility of HC concretes, they constitute a more rugged immobilization sub-system. This paper compares leach characteristics of HCs with those of radwaste-type glasses and points out why hydroceramic solidification makes more sense than vitrification for US defense-type reprocessing waste. Electronic Publication     

Melting characteristics during the vitrification of MSWI fly ash with a pilot-scale diesel oil furnace

Treatment of municipal solid waste incineration (MSWI) fly ash is becoming an important issue in China. A pilot-scale experiment was carried out to treat MSWI fly ash by using a diesel oil furnace (DOF) for more than 6 months. The effects of melting temperature on volume reduction, weight loss, compositional changes, and toxicity of leach water for molten slag have been investigated and reported. Results indicated that the volume reduction fraction of raw fly ash (RFA) and washed-fly ash (WFA) was 75–80% and the weight loss fraction was 23.8–30% at 1260–1350 °C. During the vitrification, CaO, A1₂O₃, and SiO₂ percentages in fly ash increased as the temperature increased, especially for SiO₂, which was caused by both the decomposition of carbonates or sulfates and the volatilization of metal chlorides because the main components in secondary fly ash collected from fabric filter bags were NaCl and KCl. The leaching concentrations of heavy metals in molten slag were lower than the standard values of TCLP. The releasing levels of dioxin and other pollutants (such as SO₂, HCl, CO, NO_x, etc.) in flue gas were all lower than the Chinese standard.     

攀枝花钛铁矿流态化盐酸浸出的动力学研究

本文探讨了攀枝花钛铁矿流态化盐酸漫出过程中金红石生成的机理和浸出动力学,揭示了表观选择浸出的本质,指出了产物层生成后的浸出速度仍然受未反应核界面化学反应控制。     

湿法炼锌超浸渣的浮选研究

某铅锌冶炼厂湿法炼锌超浸渣组成复杂、酸度高、粒度细,存在部分硅胶,是一种难选物料。采用一粗、一扫、一次空白精选流程,添加硫化钠—丁铵黑药组合剂混合浮选铅、银,可获良好指标。     

Selective Separation of Gallium from Acidic Leach Solutions by Emulsion Liquid Membranes

Abstract

The separation and concentration of gallium from acidic leach solutions, containing various other ions such as iron, cobalt, nickel, zinc, cadmium, lead, copper, and aluminium, by an emulsion liquid membrane (ELM) technique using tributyl phosphate (TBP) as carrier has been presented. Liquid membrane consists of a diluent, a surfactant (ECA 4360J), and an extractant (TBP), and 0.1 M HCl or 0.1 M H₂SO₄ were used as the stripping solution. The important variables governing the permeation of gallium and their effect on the separation process have been studied. These variables were membrane type and composition, mixing speed, diluent type, surfactant concentration, extractant concentration, HCl concentration in the feed, acid type of stripping phase, feed concentration, and treatment ratio. The optimum conditions were determined. It was possible to selectively extract 96.0% of gallium from the acidic leach solutions, containing Fe, Co, Ni, Zn, Cd, Pb, Cu, and Al, at the optimum conditions.