Abstract:

Aiming at the problems of selective iron removal from sulfuric acid cinder and cyanide tailings, the technology of iron removal and the valuable metals enrichment such as gold and silver by oxalic acid and ammonium oxalate was proposed. The species distribution diagrams of Fe(Ⅲ) and C₂O{}_{\mathrm{4}}^{\mathrm{2}-} in Fe³⁺-C₂O{}_{\mathrm{4}}^{\mathrm{2}-}-H₂O solution were drawn. The relationships between Fe(Ⅲ) species distribution and the pH, the molar concentration ratio of [C₂O{}_{\mathrm{4}}^{\mathrm{2}-}]_TOT to [Fe³⁺]_TOT and the liquid to solid ratio were analyzed. The relationship between the leaching effect of hematite and the species distribution of Fe(Ⅲ) in the leaching solution was revealed and the technologies of resource utilization of the leaching solution were also discussed. Results showed that the pH and the molar concentration ratio of [C₂O{}_{\mathrm{4}}^{\mathrm{2}-}]_TOT to [Fe³⁺]_TOT were the main factors affecting the species distribution of Fe(Ⅲ), and its species distribution in the leaching solution determined the leaching effect and the leaching time of hematite. In order to shorten the iron removal time and improve leaching effect, the molar ratio of [C₂O{}_{\mathrm{4}}^{\mathrm{2}-}]_TOT to [Fe³⁺]_TOT should be higher than 3, and the pH should be controlled near the minimum pH when the Fe(C₂O₄){}_{\mathrm{3}}^{\mathrm{3}-} distribution fraction reached 1. The iron removal technology of oxalate and ammonium oxalate had a short time and a good iron removal effect, and it was beneficial to concentrate gold, silver and metal sulfide as well as the resource utilization of the leaching solution. The research results would provide the theoretical and technical support for efficient, clean and resource utilization of these industrial solid wastes containing gold and hematite, which were produced in gold smelting industry and synthetic sulfuric acid industry.

Key words: sulphuric acid cinder, cyanide tailings, selectivity, leach, solubility, species distribution

摘要：

针对硫酸烧渣和氰化尾渣选择性除铁过程中存在的问题，提出草酸-草酸铵除铁富集金银等有价金属的技术。计算绘制了Fe³⁺-C₂O{}_{\mathrm{4}}^{\mathrm{2}-}-H₂O溶液中Fe(Ⅲ)及C₂O{}_{\mathrm{4}}^{\mathrm{2}-}的形态分布图，分析了其形态分布与pH、[C₂O{}_{\mathrm{4}}^{\mathrm{2}-}]_TOT/[Fe³⁺]_TOT物质的量浓度比以及液固比的关系，揭示赤铁矿浸出效果与浸出液中Fe(Ⅲ)形态分布的关系，并探讨了浸出液资源化利用工艺。结果表明：pH和[C₂O{}_{\mathrm{4}}^{\mathrm{2}-}]_TOT/[Fe³⁺]_TOT物质的量浓度比是影响Fe³⁺形态分布的主要因素，而浸出液中Fe(Ⅲ)的形态分布决定赤铁矿的浸出效果与浸出时间。要缩短除铁时间，提高赤铁矿浸出效果，则[C₂O{}_{\mathrm{4}}^{\mathrm{2}-}]_TOT/[Fe³⁺]_TOT物质的量浓度比要大于3，且pH宜控制在Fe(C₂O₄){}_{\mathrm{3}}^{\mathrm{3}-}分配分数达到1时的最小pH附近。草酸-草酸铵除铁时间短，除铁效果好，且有利于金、银及金属硫化物的富集以及浸出液的资源化利用。研究结果以期为高效、清洁、资源化利用黄金冶炼工业和合成硫酸工业产出的大宗固废提供理论与技术支持。

关键词: 硫酸烧渣, 氰化尾渣, 选择性, 浸出, 溶解性, 形态分布