Method for recovery of zinc by countercurrent leaching
AssigneeOutokumpu Oyj
InventorsAimo Jarvinen, Marko Lahtinen, Heikki Takala
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Abstract
The invention relates to method for leaching zinc-containing materials in connection with the electrolytic recovery of zinc. According to this method, the feed materials i.e. zinc calcine and zinc sulphide, are leached in three stages, in which he sulphuric acid content of the stages rises in accordance with the direction in which the solids are moving. The solids and solution formed in the leaching stages are routed throughout the process countercurrently in relation to each other.
Claims14
A method for recovering zinc from a zinc calcine and zinc sulphide concentrate in connection with an electrolytic precipitation of zinc, whereby a zinc sulphate solution obtained from a first leaching stage is directed via solution purification to zinc electrolysis and iron contained in raw materials is precipitated as jarosite, wherein the leaching of zinc calcine and zinc sulphide concentrate is performed in three stages in atmospheric conditions and at a temperature between 80° C. and the boiling point of the solution, whereby solids and solution move countercurrently in relation to each other and acid content of the leaching stages rises in the direction of the flow of the solids, wherein the concentrate leaching and iron precipitation take place in the second stage.
Dependencies are inferred from the claim text.