草酸-草酸钠浸出焙烧氰化尾渣中赤铁矿工艺的优化研究

Process optimization of leaching hematite from the roasted cyanide tailings by oxalic acid-sodium oxalate

为了获得H_(2)C_(2)O_(4)-Na_(2)C_(2)O_(4)浸出焙烧氰化尾渣中赤铁矿的工艺条件,在单因素试验结果的基础上,采用响应面法(RSM)优化其浸出工艺。结果表明:H_(2)C_(2)O_(4)-Na_(2)C_(2)O_(4)除铁优化条件为n(H_(2)C_(2)O_(4))/n(Na_(2)C_(2)O_(4))0.92、C 2O 2-4过量倍数1.25、浸出温度95℃、液固比8∶1。各因素对除铁效果影响大小排序为浸出温度、液固比、n(H_(2)C_(2)O_(4))/n(Na_(2)C_(2)O_(4))、C_(2)O_(4)^(2-)过量倍数,其中,浸出温度与液固比的交互作用、C_(2)O_(4)^(2-)过量倍数与浸出温度的交互作用较为显著。在优化条件下,铁浸出率预测值和实测值分别为98.65%和98.14%,相对误差为-0.52%。草酸-草酸钠作为除铁剂,浸出过程草酸先溶解,草酸钠后溶解,且二者的摩尔比、C_(2)O_(4)^(2-)过量倍数影响浸出体系pH,而浸出pH和c(C_(2)O_(4)^(2-))应满足Fe^(3+)转化成[Fe(C_(2)O_(4))_(3)]^(3-)。研究结果对金焙砂、硫酸烧渣及其他含赤铁矿矿物降铁富集金银等有价金属具有重要借鉴意义。

In order to obtain the process conditions for leaching hematite from roasted cyanide tailings with H 2C 2O 4-NaC 2O 4,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 H 2C 2O 4-Na 2C 2O 4 are as follows:n(H 2C 2O 4)/n(Na 2C 2O 4)is 0.92,overdosing is 1.25 times the theoretical amount C 2O 2-4,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(H 2C 2O 4)/n(Na 2C 2O 4),and the overdosing times of C 2O 2-4,among which the interaction between leaching temperature and the liquid-solid ratio,the overdosing times of C 2O 2-4 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 C 2O 2-4 affect the leaching pH,while leaching pH and c(C 2O 2-4)should satisfy Fe 3+to form[Fe(C 2O 4)3]3-.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.