锌精矿浸出尾渣中有价金属回收闭环工艺探索

Exploration on closed-loop process for recovery of valuable metals from zinc concentrate leaching residue

青海某锌冶炼厂有大量硫浮选尾渣堆存,该尾渣中含锌2%~3%,含铅达10%以上,含铁高达30%左右,针对此情况,该厂配套建设了"火法+湿法"尾渣无害化处理工艺。尾矿渣和热滤渣混合制粒后经富氧侧吹炉冶炼,熔炼炉渣再进入烟化炉进行挥发,次氧化锌被富集进入烟尘;产出的次氧化锌经过两段浸出+萃取工艺可以回收锌及其他有价金属。该工艺中,烟尘中锌的回收率约为80%,铟的回收率约为75%;侧吹炉产生的烟尘可以回收处理,烟化炉产生的冶炼渣可用于制作水泥或是环保砖;湿法工艺的浸出液返回湿法炼锌系统,富集的金属及浸出渣外售。整个工艺不产生废弃物,实现了绿色冶金的目标。

There is a large stockpile of sulfur flotation tailings in a refinery in Qinghai, which contain 2%~3% of Zn, more than 10% of Pb and about 30% of Fe. To address this issue, this plant has adopted, as supporting measure, the pyrometallurgical + hydrometallurgical process to harmlessly treat the tailings. The tailings and hot filtration residue are mixed, pelletized, and smelted in an oxygen-enriched side-blowing furnace, the smelting slag is then fed into a fuming furnace to be volatilized, and the Zn hypoxide is enriched to enter off-gas dust;the produced Zn hypoxide is subject to two stages of leaching plus extraction process to recover Zn and other valuable metals. Inthis process, the recovery of zinc in off-gas dust is about 80%, that of indium about 75%;the off-gas dust from side-blowing furnace can be recovered and treated;the smelting slag from the fuming furnace can be used to make cement or eco-friendly bricks;the leaching liquid from hydrometallurgical process is returned to the hydrometallurgical system for zinc;the enriched metals and leaching residue can be sold, in this way, the objective of green metallurgy can be realized.