铜电解精炼液净化脱砷新工艺

New process for purifying and removing arsenic from copper refining electrolyte liquid

电解精炼铜过程中,粗铜中的砷不可避免地溶解到电解液中,进而影响精炼铜效率。由于铜精炼电解液是酸性体系,常用的萃取法和化学沉淀法很难在该环境中取得理想效果。现有电解精炼厂大多选用电沉积法,以牺牲电耗的方式降低电解液中的砷浓度,然而这种方式能耗大、沉积效率低。通过模拟现有电沉积脱砷工艺,发现当铜电解精炼液中铜浓度降至10 g/L时,砷才会较快沉积。结合现有铜电解精炼厂工艺特点对脱砷工艺进行改造,实现高效砷脱除,且产物以铜砷合金形式赋存,可以外售以平衡成本。改进后的工艺相较于现有工艺仅增设不同区段之间的电解液调节储存罐,通过平衡各区段中电解液铜离子浓度,实现砷的快速电沉积脱除。改进后的工艺不仅降低了砷脱除所需的电耗,同时减少了脱砷所需的时间,大大降低脱砷成本。此外,沉积脱砷后的产物中含铜可高达60%左右,是质量较高的粗铜,足以平衡脱砷过程的电耗,且可带来一定收益。

Arsenic in crude copper is inevitably dissolved in the electrolyte during the process of electrolytic refining copper,which will affect the efficiency of refining copper.Common methods,such as extraction and chemical precipitation,were difficult to achieve ideal results in acid copper refining system.Electrodeposition was used mostly in the existing electrolytic refineries.In this process,the concentration of arsenic was reduced by the power consumption.However,the high energy comsumption and low efficiency limit its application.In this work,it is found that the deposit of arsenic was fast in 10 g/L copper electrolyte by simulating the existing electrodeposition dearsenic process.Combining the characteristics of the existing electrolytic copper refinery,the arsenic removal process is modified to achieve efficient arsenic removal.More importantly,the product is in the form of copper-arsenic alloy which can be sold to balance the cost.Compared with the existing process,the modified process only adds electrolyte adjustment storage tanks between different sections.The rapid electrodeposition removal of arsenic was achieved by balancing the concentration of copper ions in each section electrolyte.Furthermore,the modified process reduces the power consumption and time for arsenic removal.In addition,the content of copper in the electrodeposit product can be as high as about 60%,which is high-quality blister copper.