As we all know, purification is the key process for producing high purity zinc sulfate, and the aim of purify is to get rid off the impurities such as Fe2+,Mn2+,Cd2+,Ni2+and so on.
Using hydrogen peroxide for deironing, and nearly 90% Fe2+can be gotten rid off from zinc sulfate solutions, and then using a little bleaching powder to remove the remaining Fe2+ and remove some Mn2+,and then add potassium permanganate to remove the remaining Mn2+.
The advantages of using this craft are as follows:
1. The content of Cl can be controlled between 2.0-2.5 g/l, while if you use the craft with no hydrogen peroxide, the content of Cl will be above 3.0 g/l.
2. Using too much of bleaching powder will make huge amount of bleaching powder dross, while if you use hydrogen peroxide, few dross and higher Zn recovery.
Thus, it is important to control the purification craft well to produce high purity zinc sulfate. The best way is to use hydrogen peroxide instead of huge amount of bleaching powder.
