Abstract: A pilot test was made on the production of zinc oxide from a waste solution of the indium smelting of a smeltery-the residual solution of indium extraction. The residual solution was treated first to neutralize its residual acid and to remove preliminarily the iron by air jetting method, and then purified in four stages using potassium permanganate and zinc power to remove the impurities such as residual iron, manganese, arsenic, antimony, copper, cadmium, etc. Then, sodium carbonate was added to precipitate the zinc and the resultant basic zinc carbonate was rinsed for three times and then dried, roasted and crushed to get a zinc oxide product. The testing indicates that the product reaches the standards for 1st grade industrial active zinc oxide product.

Key words: Residual solution of indium extraction, Iron removal by air jetting, Purification, Zinc precipitation, Zinc oxide