Study On Recovering Copper From Electroplating Sludge

The electroplating sludge with a large amount of Cu, Ni, Zn, Cr, Fe, and other heavy metals is engendered in electroplating industry, as electroplating production process and the different vary, the ingredients are very complicated.The electroplating sludge cause harm to the environment and human health, which is one of recognized hazards at home and abroad. The electroplating sludge containing a variety of metal components, often higher than their metal-grade ore is a cheap secondary renewable resource. To recycle resources from electroplating sludge, this paper studyed how to receive copper sulfate with some process, as acid leaching,impurity removal,extraction,crystallization and dry products and copper sulfate by the process of exploration.At first, this paper researched the basic nature of electroplating sludge, including the moisture content, leaching toxic, pH and heavy metal content determination. It indicates:①Water content is 1.17%; Leaching toxic of copper was 58.76mg/L; pH of sludge is 6.2.②10g dry sludge contains copper 1.3275g, iron 3.3281g. After the basic nature of research, and for the sludge leaching products lay the foundation for the recovery.In the recovery process of electroplating sludge, it researched on acid leaching process, N902—sulfonated kerosene extraction of copper, and copper sulfate stripping and the recovery.①in acid leaching process , the addition of sulfuric acid, the ratio of liquid to solid, leaching time, leaching temperature, feeding on the fineness were studyed. The results showe that: When acid dosage being 8 ml,liquid/solid ratio being 5, leaching time being 1h, leaching temperature being normal temperature, feeding fineness being 100 heads, copper leaching rate is 98.73% and iron leaching rate is 97.91%.②kerosene in the N902 - sulfonated copper extraction in the process of studying the extraction equilibrium time, pH of water, extraction agent concentration, compared to the impact on the extraction of copper. The results show that: When the extraction equilibrium time of 2 min, water pH being 1.5 to 1.7, extractant concentration of 30%, O/A is 1, copper extraction rate is 98.7%, which the copper is essential separated from the liquid.③With sulfuric acid stripping, when the concentration of sulfuric acid to 4 mol/L, copper stripping rate is 94.6%. The concentration of copper is 4.86 g/L.④crystallization method of recovery being concentrated copper sulfate products, product content is as high as 99.14%.After recoverying copper, the solution contains large amounts of iron. the main products is sodium sulfate and iron oxide.This paper also studied the curing residue test. Cement and gravel could cure residue. Toxic leaching of copper leaching concentration is 3.21 mg/L which realizes the sound of sludge.