Abstract:Zijinshan low-grade secondary sulfide copper mine adopts green, high efficiency and low carbon biological copper extraction process, with an annual output of 20 kt of cathode copper. The high sulfur copper ratio in the ore allows the bioleaching process to occur spontaneously without the need for acid supplement and any additives other than water. The net acid production per ton of ore is about 3 kg, resulting in excess acid iron in bioleaching process, need to open circuit, and the spray cycle is economically restricted, generally not more than 200 days. After the end of the spray cycle, the old dump is not removed and been sealed in situ for greening. However, ecological restoration is difficult and costly in acidic environment. The leaching behavior of excess iron and acid solution on the old dump after copper leaching cycle was studied, and the resource utilization direction of the waste was preliminarily studied.