pH值对臭氧氧化深度去除湿法炼锌溶液中铁的影响

The Effect of pH Value on Deep Removal of Iron in Zinc Hydrometallurgy Solution by Ozonation

铁是湿法炼锌过程中的有害杂质成分,必须在锌电积前深度去除。研究了在臭氧氧化条件下,pH值对ZnSO4溶液中除铁性能的影响。结果表明,铁的去除率和锌的损失率随pH值的升高而增大,在pH值为4.5时,铁去除率达到99.98%,渣中Zn和Fe含量分别为1.52%和34.61%,沉淀渣主要是由FeOOH和ZnSO_(4)·xH_(2)O组成。随着pH值的增加,铁沉淀物颗粒趋于团聚,粒径显著增大,沉淀的可过滤性提高。锌通过包裹在沉淀物的晶格中或被沉淀物所吸附而损失在铁沉淀物中。臭氧氧化过程中,Fe^(3+)/Fe^(2+)值及臭氧消耗量随pH值的增加而增加,从而导致ZnSO4溶液的电位值减小。

Iron is an undesirable constituent in zinc sulfate leachate and must be deeply removed before zinc electrowinning process.This paper has dealt with experimental investigations related to effect of pH value on removal of iron via ozonation.Results show that the iron removal ratio and the zinc loss increase with increasing of pH value.Controlling the pH value at 4.5,the iron removal ratio reaches 99.98%,and Zn and Fe contents in residue are 1.52%and 34.61%,respectively.The precipitates are mainly composed of FeOOH and ZnSO_(4)·xH_(2)O.As the pH value increases,the iron precipitate particles tend to agglomerate,and the particle size increases significantly,finally the filterability of the precipitate improves.Zinc is lost in iron precipitates by wrapping into the lattices and adsorption on the surface of the precipitate particles.In the process of ozonation,the ratio of Fe^(3+)/Fe^(2+)and ozone consumption increase with the increase of pH value,which lead to the decrease of potential value of ZnSO_(4) solution.