Abstract: A method for producing copper sulfate from waste copper-containing liquid including the steps of recovery of acidic and basic copper-containing liquid, and neutralization of the liquid to form crystalline copper sulfate, wherein the ratio of acidic to basic copper-containing liquid, temperature, pH value and the concentration of copper ion in the resultant solution of each step is being controlled such that the solid copper sulfate is obtained in high yield and purity and will have a larger particle size, and at the same time, the filtrate will contain copper ion in a concentration below 0.3 ppm before being expelled to the surroundings.