选冶联合流程回收铜银金的工艺

A united technique for recovering Au, Ag, Cu from mixed flotation concentrate

采用ＤＸ 低碱度抑制剂， 用ＮａＯＨ 调节ｐＨ， 在ｐＨ＝ ９ ～１０ 的范围内浮铜抑硫， 使混合精矿中的有价金属与黄铁矿分离， 再选精矿产率２０ ％ ～３０ ％ ， 尾矿含金低于３ ．０ ｇ／ｔ。在较低的压力下（ 氧压０ ．４ ～０ ．６ ＭＰａ） 对所得精矿进行氧压氨浸， 使硫转化为硫酸铵， 铜进入溶液， 金银留在浸渣中。分选中金、银、铜回收率分别为９５ ％ ，９０ ％ 和８５ ％ ； 分选条件为ｐＨ＝ ９ ．５ ， 捕收剂用量２００ ｇ／ｔ， ＤＸ 抑制剂３ｋｇ／ｔ。低压氨浸铜浸出率为９５ ％ ， 浸出压力０ ．５ ＭＰａ， 温度１２０ ℃， 时间３ ｈ ， 氨浓度４５ ｇ／Ｌ。氰化浸出金、银浸出率为９７ ％ 和９５ ％ ， 置换率９９ ％ 和９８ ％ 。金、银、铜总回收率分别为９４ ％ ，８４ ％ 和８１ ％ 。

A weak alkaline processing technique was used to treat the flotation concentrate to separate Cu, Ag, Au from pyrite, by using sodium hydroxide as pH adjusting reagent and DX as depressant. The recovery of product was 20%～30% and the gold content in the tailings was below 3.0 g/t. As a result, lots of useless minerals were discarded, the grade of useful minerals was increased and the later metallurgical volume was restricted. Then under lower leaching pressure (0.4～0.6 MPa), the product was leached by ammonia to extract copper, the chemical byproduct is (NH 4) 2SO 4 and Au/Ag residue. So many problems such as elemental sulfur and higher demands of equipment confronted frequently in the traditional process were avoided. The leaching residue was cyanided to recover gold and silver in the presence of rich oxygen. The separation recovery of gold, silver and copper were 95%, 90% and 85% respectively, under the condition of pH=9.5, DX consumption 3 kg/t and collector dosage 200 g/t. The recovery of copper in ammonia leaching was 95%, under the condition of oxygen pressure 0. 5 MPa, temperature 120 ℃, leaching time 3 h and NH 3 45 g/L. The total recovery index for Au, Ag, Cu were 94%, 84% and 81%, respectively.