HYDROMETALLURGICAL METHOD FOR RECOVERING ZINC IN A SULPHURIC MEDIUM FROM ZINC SULPHIDE CONCENTRATES HAVING A HIGH IRON CONTENT

摘要

This method is based in the recirculation of an iron free solution or a solution with low iron content in such a manner that the final acidity conditions obtained are ideal for iron to efficiently precipitate as jarosite. In a variation of the invention the zinc concentrate is subjected to the following stages:
a. Roasting of at least part of the zinc concentrate.
b. Neutral leaching where zinc oxide is dissolved.
c. Acid leaching where zinc ferrites are leached.
d. Reduction of the Fe +++ contained in the solution to Fe ++ by adding zinc concentrate and diluting it with a zinc sulphate solution resulting from stage (f) to lower the concentration of Fe ++ .
e. Neutralizing the acidity in the solution with calcine.
h. Iron oxidation and jarosite precipitation, free of contaminating solids, by means of the injection of oxygen or oxygen-enriched air and the addition of an alkali or a Na + o NH4 + salt.