High-grade heavy metal elements in copper slag (CS) are worth recovering. Unfortunately, the high viscosity of leaching solution, low leaching efficiency, difficult filtration and low separation efficiency of valuable components exist in the traditional sulfuric acid leaching process. In this study, the above problems are solved by sulfuric acid pretreatment + curing + water leaching. Moreover, iron, cobalt and copper ions in solution are separated by stepwise precipitation. The final iron, cobalt, copper and silicon recoveries are 99.01 %, 98.45 %, 93.13 % and 99.52 %, respectively. Thermodynamic calculations show that H4SiO4 can be converted to insoluble SiO2 to improve filtration properties under curing conditions of sulfur dioxide partial pressures of 10−20∼0 atm, oxygen partial pressures of 10−20∼0 atm and 400–600k. Simulation studies of the phase equilibria of the components of the leach solution by Visual MINTEQ showed that the oxidation of Fe2+ to Fe3+ is necessary for the removal of Fe2+ from the solution by precipitation. This study provides a new idea for the efficient utilization of CS.

中文翻译：

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从铜渣中高效回收铁、钴、铜和硅的非常规方法


铜渣（CS）中的高品位重金属元素值得回收。传统的硫酸浸出工艺存在浸出液粘度高、浸出效率低、过滤困难、有价成分分离效率低等问题。本研究通过硫酸预处理+养护+水浸解决了上述问题。此外，通过逐步沉淀分离溶液中的铁、钴和铜离子。最终铁、钴、铜和硅的回收率分别为99.01%、98.45%、93.13%和99.52%。热力学计算表明，在二氧化硫分压10−20∼0 atm、氧分压10−20∼0 atm、400~600k的固化条件下，H4SiO4可以转化为不溶性SiO2，以改善过滤性能。通过 Visual MINTEQ 对浸出溶液组分的相平衡进行的模拟研究表明，Fe2+ 氧化为 Fe3+ 对于通过沉淀从溶液中去除 Fe2+ 是必要的。该研究为CS的高效利用提供了新思路。