刚果(金)加丹加铜钴氧化矿石中铁的赋存状态对钴酸浸效果的影响

Influencing of Occurrence State of Iron on Co Acid Leaching in Cu-Co Oxide Ores from Katanga Copper-Cobalt Belt at Congo(DRC)

刚果(金)加丹加铜钴矿带上A和B两个矿区矿样的铜、钴赋存状态及铜、钴矿物组成相同,采用硫酸浸出工艺回收铜、钴,当浸出条件相同时,两矿样中铜的浸出率都达到90%以上,而钴的浸出率相差很大,A样达到85%,而B样仅为30%。通过工艺矿物学系统研究及浸出试验,查明铁的赋存状态不同是引起两矿样中钴浸出率存在差异的主要因素,即A样中80%的铁以铁白云石等碳酸铁形式存在,在酸性介质中容易释放出还原性Fe2+,有利于钴的浸出,而B样中80%铁以绿泥石形式存在,在酸性介质中不易释放出还原性Fe2+,导致其中钴浸出率偏低。根据研究结果提出将两矿样按比例混合浸出,可在提高钴浸出率的同时减少还原剂的使用。

The occurrence states of copper, cobalt and their mineral composition of ore sample from a mine area of Katanga copper-cobalt belt in Congo （DRC） is relatively equal to the B mine area＇ s. Using sulfuric acid leaching process recycling of copper and cobalt, under the same leaching conditions, the copper leaching rate is more than 90%, while it has a big difference in cobalt leaching rate, with the leaching rate of 85% in sample A and 30% in sample B respectively. Through the process mineralogy studies and leaching tests, it is identified the occurrence state of iron is the internal factors resulting in the difference of the cobalt leaching rate in the two samples. Namely, 80% of iron exists in the form of ankerite （iron carbonate） in sample A, and it is easy to be released in the form of the reducing ion of Fe2＋in acidic media, and is conducive to the leaching of cobalt, while 80% iron exists in the form of chlorite in sample B, it is difficult to be released in the form of the reducing ion of Fe2＋ in acidic medium, resulting in the low cobalt leaching rate. It is proposed that mixing the two samples in proper proportion can improve cobalt leaching rate and save reagent consumption.