Modelling of calcium sulphate solubility in concentrated multi-component sulphate solutions

The chemistry of several calcium sulphate systems was successfully modelled in multi-component acid-containing sulphate solutions using the mixed solvent electrolyte (MSE) model for calculating the mean activity coefficients of the electrolyte species. The modelling involved the fitting of binary mean activity, heat capacity and solubility data, as well as ternary solubility data. The developed model was shown to accurately predict the solubility of calcium sulphate from 25 to 95 °C in simulated zinc sulphate processing solutions containing MgSO₄, MnSO₄, Fe₂(SO₄)₃, Na₂SO₄, (NH₄)₂SO₄ and H₂SO₄. The addition of H₂SO₄ results in a significant increase in the calcium sulphate solubility compared to that in water. By increasing the acid concentration, gypsum, which is a metastable phase above 40 °C, dehydrates to anhydrite, and the conversion results in a decrease in the solubility of calcium sulphate. In ZnSO₄–H₂SO₄ solutions, it was found that increasing MgSO₄, Na₂SO₄, Fe₂(SO₄)₃ and (NH₄)₂SO₄ concentrations do not have a pronounced effect on the solubility of calcium sulphate. From a practical perspective, the model is valuable tool for assessing calcium sulphate solubilities over abroad temperature range and for dilute to concentrated multi-component solutions.     

Electrolytic production of copper from chalcopyrite

The transition to renewable energy infrastructure necessitates rapid growth in copper production, averaging at least 3.5% annually to 2050. The current smelting–converting–electrorefining route must be revisited considering these future prospects as ore grades deplete and the costs to mitigate emissions to the environment increase. Here, we investigate electrolytic alternatives, reviewing the background and recent developments for four classes of electrolytes to directly decompose the most important industrial copper mineral, chalcopyrite: aqueous solutions, ionic liquids, molten salts, and molten sulfides. These electrolytes are discussed in the framework of electrochemical engineering, as applied to the electrolytic decomposition of chalcopyrite. A vision is proposed in which an electrolytic technique, integrated with low cost and sustainable power, enables the production of unprecedented annual tonnages of copper from low-grade chalcopyrite, with valuable by-products and enhanced selectivity for impurities.     

废弃电路板的化学处理方法

随着电子产业的迅速发展,印刷电路板的废弃量也在逐年增加。大量的废弃印刷电路板可能对环境造成严重的污染。废弃印刷电路板具有极高回收价值,如果采用适当的方法对其进行回收,不但可以节省我国日益紧缺的矿产资源,而且对环境保护有着极大的意义。本文阐述了废弃电路板资源回收的经济意义和环境意义,并详细介绍了湿法处理、热解法处理和超临...     

回收废锂离子电池中贵金属元素的研究进展

随着电力储能需求的激增,大量投入市场的锂离子电池在废弃时面临回收率低下的问题。废弃锂电池中锂、钴等贵金属作为战略性资源,存在短缺风险,对其提取并回收在减少环境污染的同时具有显著经济意义。湿法冶金工艺因其低能耗污染等优势,在回收锂电池贵金属的研究中应用广泛。本文在阐述锂电池结构的基础上,从浸出液、预处理等方面对工艺与机制进行深入分析,并简述以生物浸出液为主的生物湿法冶金作用机制与影响因素。此外,火法冶金技术在锂电池回收方面发展势头迅猛,文章归纳近期新兴工艺与回收机理。最后,总结现阶段工艺回收废锂离子电池中贵金属的局限,对未来技术升级进行展望,旨在促进贵金属回收进程,助力实现国家“双碳”目标。     

湿法电解含金萃取有机相制备金的研究

提出了一种在湿法冶金同时电解载金属有机相制备金属的新方法.并通过电解磷酸三丁酯(TBP)萃取Au(CN)₂^--R₄N⁺的载金有机相制金.考察了电解技术条件、Au浓度、电解质浓度及还原剂等因素对Au回收率的影响.结果表明,此方法不仅可省去冗长的反萃和还原等步骤,而且可以直接以高回收率制备高纯度的金箔;在电解液中加入少量还原剂可明显提高金的回收率.该法也适用于制备银和铜,制备银时所用体系与金相似,但制备铜则在D₂EHPA-正庚烷为载铜有机相及电解质的酸性溶液为水相的体系中进行.     

Solvent extraction in hydrometallurgy: the role of organophosphorus extractants

Solvent extraction (SX) has come to be one of the most important separation processes in hydrometallurgy. Phosphorus-based extractants have proved to be of particular importance, especially for the separation of cobalt from nickel. However it was not until the dialkyl phosphinic acid reagent, CYANEX 272, and its dithio analogue CYANEX 301, became available that liquors containing very low Co:Ni ratios of at least 1:40 to even >1:100 could be treated. This has opened the way to the direct application of SX for the separation of Co from Ni in liquors derived from the leaching of nickel mattes from the smelting of nickel sulphide ores and from the pressure acid leaching of nickel laterite ores. This paper describes the development of the range of Cytec extractants and, in particular, discusses the development of their application for the separation of cobalt from nickel. Examples of actual industrial operating plants will also be given and individual flowsheets discussed.