Patent ID: 8900535

Claim:
A method, comprising: contacting an acidic zinc- and sulphate-bearing solution comprising dissolved zinc with a calcium oxide and/or hydroxide to adjust a pH of the acidic zinc- and sulphate-bearing solution to a pH ranging from about pH 5 to about pH 14 at a temperature of the acidic zinc- and sulphate-bearing solution of greater than about 30° C. but no more than about 95° C. to precipitate at least most of the zinc as zinc sulphate and at least most of the calcium oxide and/or hydroxide as gypsum, wherein the precipitated zinc sulphate has at least one of a mean, median, and P 90 particle size less than about 50 microns and the gypsum has at least one of a mean, median, and P 90 particle size of more than about 50 microns; and size separating the precipitated zinc sulphate from the gypsum to form a zinc sulphate-rich product and a gypsum-rich product, wherein at least about 35% of the dissolved zinc is in the zinc sulphate-rich product and at least about 50% of the gypsum is in the gypsum-rich product.