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Heavy metal sewage always comes from electroplating, electronics and metallurgy industry. Especially, the ingredients of sewage from electroplating and electronic industry are very complex. Besides Cyanide (CN -) wastewater, heavy metal elements in heavy metal sludge can be divided into chrome, nickel, cadmium, zinc, copper, gold, silver and etc. heavy metal sewage holds serious harmful to natural environment. Therefore, it is paid much attention both at home and abroad. There are several disposal methods figured out. Through proper disposal methods, harmful sludge can be converted into harmless sludge. Precious heavy metal in sludge can be recycled. After purification, sewage can be recycled. Correspondingly, heavy metal emission can be reduced or eliminated.
With the rapid development of electroplating industry and electronic industry, environmental protection request is also more and more strict. At present, these industries gradually adopt clean production process, quantity control and circular economy mode. Resource recycling and closed cycle are mainstream for heavy metal sludge disposa