Abstract: In order to obtain the process conditions for leaching hematite from roasted cyanide tailings with H2C2O4-NaC2O4,based on the results of the single factor experiments,the response surface method (RSM) was used to optimize the leaching process.The results show that the optimal conditions for iron removal with H2C2O4-Na2C2O4 are as follows:n(H2C2O4)/n(Na2C2O4) is 0.92,overdosing is 1.25 times the theoretical amount C2O2-4,leaching temperature is 95 ℃ and the liquid-solid ratio is 8∶1.The influence of each factor on iron removal effect is arranged in descending order as follows:temperature,liquid-solid ratio,n(H2C2O4)/n(Na2C2O4),and the overdosing times of C2O2-4,among which the interaction between leaching temperature and the liquid-solid ratio,the overdosing times of C2O2-4 and temperature are significant.Under the optimized conditions,the predicted and actual values are 98.65 % and 98.14 %,respectively,and the relative error is -0.52 %.When oxalic acid-sodium oxalate is used as iron removal agents,oxalic acid dissolves first,sodium oxalate dissolves later during the leaching process,and their molar ratio and the overdosing times of C2O2-4 affect the leaching pH,while leaching pH and c(C2O2-4) should satisfy Fe3＋ to form Fe(C2O4)33-.The research results have the important reference significance for iron removal and enrichment of valuable metals from gold roasted calcine,sulfuric acid cinder,and other minerals bearing hematite.