TREATMENT OF METAL PICKLING EFFLUENT AND RECOVERY OF THE METAL

Metal pickling is a type of surface treatment, where the surface of the ferrous metals, copper, and aluminium alloys are treated with acidic media to get rid of inorganic contaminants, rust or scale formed. Hydrochloric acid and sulphuric acid are popularly used for this purpose. This causes the industry to produce highly acidic metal pickling effluent which cannot be disposed directly without treatment as it is hazardous. Hence, to treat this metal pickling effluent, three methods are used which are by using hydrating lime, soda ash and the distillation method. These three methods are discussed in detail in this paper to prove which is the most cost effective and efficient method for large scale as well as small scale industries.