WATER PURIFICATION BY ETTRINGITE PRECIPITATION

摘要

In the invention is provided a method for removal of sulfate from water contaminated by metal ions and sulfate, comprising: 1) a coagulation step, wherein water contaminated by metal ions and sulfate is treated in an electrocoagulation (EC)-unit, whereby metal ion contaminants are precipitated as a metal ion fraction; 2) a first fractionation step; 3) a gypsum precipitation step, wherein a calcium source is added to the metal depleted water of step 2), whereby gypsum is precipitated; 4) a second fractionation step; 5) an ettringite precipitation step, wherein a calcium and aluminum source, such as calcium aluminate, is added to the sulfate and metal depleted water to promote ettringite precipitation; and 6) a third fractionation step. Also provided is a system for the method of the invention.