The kinetics of indium leaching from hard zinc residue in hydrochloric acid solution is studied after mechanically activated by stirring mill and planetary mill.After mechanical activation, the partical size of hard zinc residue decreases, especially for the one activated by stirring mill (See Figure 1 a).In addition, the peak value of DSC curve moves forword after mechanical activation.For example, the peak value moves from 420 centigrade to 367 centigrade and 415 centigrade for the hard zinc residue activated by stirring mill and planetary mill respectively (See Figure lb).