湿法炼锌提高银、铜等有价金属的生产实践

Production practice of Zinc hydrometallurgy for increasing silver, copper and other valuable metals

湿法炼锌常规浸出工艺被广为采用。内蒙古某锌冶炼厂产锌20万t/年,采用一套10万t/年的高温高酸低污染沉矾除铁工艺和一套10万t/年的“常规浸出-浮选回收银-浸出渣回转窑处理”工艺。其中在常规浸出工艺条件下,锌精矿中的银主要以硫化物形态富集于焙砂酸浸出渣中,经浮选得到银精矿,浮选尾矿进入回转窑处理得到氧化锌,再经中浸、酸浸两段浸出、浓密、过滤,回收锌、铜,铅、银等浸出富集于氧化锌酸浸渣中。原设计浮选后的银精矿直接外售,但浮选过程中大量的锌、铜等有价金属被硫化后进入银精矿,造成锌、铜等有价金属的损失,以及银、铅等金属在浮选银精矿中被稀释从而导致品位下降;本文通过实验论证使浮选后的银精矿在高温、高酸及添加氧化剂的浸出工艺,达到了锌、铜等有价金属的进一步回收,以及银精矿中银、铅品位进一步富集的双重目的,使资源达到了综合利用的目的;并在工况化生产改造过程中,充分利用原有闲置的槽罐、管道、压滤机等设备,减少了改造投资,并在工况化生产中起到了良好效果。

The conventional leaching process of zinc hydrometallurgy is widely used.A zinc smelter in Inner Mongolia produces 200000t/a of zinc.A set of 100000t/a high temperature,high acid and low pollution alum precipitation and iron removal process and a set of 100000t/a"conventional leaching flotation recovery of silver leaching residue rotary kiln treatment"process are adopted.Under the conditions of conventional leaching process,the silver in zinc concentrate is mainly enriched in the calcine acid leaching residue in the form of sulfide,and the silver concentrate is obtained by flotation.The flotation tailings are treated in the rotary kiln to obtain zinc oxide,which is then leached,thickened and filtered by intermediate leaching and acid leaching to recover zinc,copper,lead and silver,which are leached and enriched in the zinc oxide acid leaching residue.The originally designed silver concentrate after flotation is sold directly,but a large number of valuable metals such as zinc and copper enter the silver concentrate after being vulcanized in the flotation process,resulting in the loss of valuable metals such as zinc and copper,and the dilution of metals such as silver and lead in the flotation silver concentrate,resulting in the decline of grade;Through experimental demonstration,the leaching process of flotation silver concentrate at high temperature,high acid and adding oxidant has achieved the dual purpose of further recovery of valuable metals such as zinc and copper and further enrichment of silver and lead grades in silver concentrate,so as to achieve the purpose of comprehensive utilization of resources;In the process of working condition production transformation,the original idle tanks,pipelines,filter presses and other equipment are fully utilized,the transformation investment is reduced,and good results are achieved in working condition production.