协同催化氧化体系中锌精矿的直接浸出

LEACHING OF ZINC SULPHIDE CONCENTRATES WITH SYNERGISTIC OXIDATION CATALYST

由铁离子、铜离子和氮氧物等电子传递媒介组成协同催化氧化剂。在硫酸介质中，在常压低温条件下直接浸出硫化锌精矿，硫化物中的硫部分转化为元素硫和部分转化为硫酸。浸取时，多种催化氧化剂同时在液固界面、气固界面参加反应，又同时在气相中、液相中、气液界面获得再生，从而极大地提高了浸出速率。在实验条件下，锌的回收率达９５％以上。在浸出初期，浸出过程由表面化学反应动力学控制。随着浸出过程的进行，产生的硫磺及不溶硫酸盐在矿粒周围形成的包裹层越来越厚，固－液相界面中的扩散过程逐渐变成浸出过程的限制步骤。温度、粒度、酸度、催化剂浓度等对浸出速度均有较大影响，本文提出的协同催化氧化浸出工艺对矿物品位和形态无严格要求，可以处理不宜焙烧的复杂矿和低品位矿。过程不排放灰尘、ＳＯ２，Ａｓ２Ｏ３、汞等有毒烟气。与现有的直接浸出技术比较，协同催化氧化浸出的优点为在常温、常压或微负压条件下操作；应用廉价的空气而不用纯氧；设备的腐蚀问题容易得到解决。

おy using iron ions, copper ions and nitrogen oxides as synergistic oxidation catalysts, the leaching of complex sulphide ore or concentrates of zinc was carried out in the sulphuric acid media at ambient pressure and low temperature Sulphur in sulphide partly converted to S0 and partly to SO_4~2- The chemical reactios between ore particles and catalysts took place at the liquidsolid interfaces and gassolid interfaces simultaneously The catalysts were quickly regenerated in gas phase, liquid phase and gasliquid interfaces Therefore it only took about 2 hours to finish the leaching process, and the recovery efficiency of zinc was over 95% In the beginning, the leaching is a surface reaction controlled process When the zinc sulphide concentrates dissolve, S0 and PbSO_4 formed on the surfaces of ore particles will hinder the contacting of leaching agents with ore particles The leaching process will be controlled by diffusion steps The synergistic catalyst technology can be applied to deal with complex lower grade ores It is a clean process with minimal emission of SO_2,As_2O_3,Hg and dusts Air instead of pure oxygen may be used The problems of equipment corrosion are easy to be solved