Abstract: Influence of additive dosage,leaching time and temperature,acid/ore ratio on Chromium ion leaching rate was investigated with 8-hydroxquinoline,potassium ethyl xanthate,hexadecyltrimethyl ammonium bromide,tributyl phosphate and lemon acid as additive.The results showed that leaching rate of Cr6+ reaches 38.11% when addition 0.8% potassium ethyl xanthate in temperature is 60 ℃,acid/ore ratio is 0.3∶1,liquid/solid ratio is　1∶4,and leaching time is 90　min;the leaching rate is 1.5 times of that obtained by heating leaching.

Key words: additive, manganese residue, chromium ion, heating leaching