草酸配位浸出二段焙砂中包裹金的赤铁矿

Oxalic Acid Coordination Leaching of Hematite Wrapped with Gold in Two-stage Calcine

草酸根(ox2-)对三价铁具有强的配位能力,可用草酸配位浸出二段焙砂中包裹金的赤铁矿,提高金的回收率。考察了草酸用量、液固比、浸出温度和时间对二段焙砂中铁浸出率的影响。结果表明,用1.17倍理论量的草酸在液固比为12 mL/g时于90℃浸出2 h,铁浸出率达到75.8%以上。除铁渣进一步氰化浸出,渣中金品位为8.8 g/t,低于直接氰化浸出渣12.3 g/t的金品位。草酸浸出液主要成分为具有光催化活性的Fe(ox)+和Fe(ox)2-,可采用光催化法回收铁、再生草酸,再生的草酸可返回浸铁过程。

Oxalate(ox2-)has the strong coordination ability to ferric iron,so gold wrapped by hematite in two-stage calcine can be leached with oxalic acid to improve the recovery rate of gold.The influence of oxalic acid dosage,solid to liquid ratio,leaching temperature and time on the leaching rate of iron were investigated.The results showed that the iron leaching rate was over 75.8%under the leaching condition of 1.17 times of the theoretical dosage of oxalic acid and a liquid to solid rate of 12 mL/g for 2 h at 90°C.After iron was removed,the residue was further leached by cyanide,and the content of gold was 8.8 g/t,which was lower than 12.3 g/t of the cyanide direct leaching calcine.The main components of the leaching solution are Fe(ox)+and Fe(ox)2-with photocatalytic activity,iron can be recovered by photocatalysis,and the regenerated H2ox can be return to the leaching process.