Patent ID: 6270738
Filing Date: 2001-08-07
Classification: C01G,C02F

Abstract:
A process for preparing a usable product containing ferric iron from an impure ferric sulfate solution, the process comprising:providing a first sulfate solution comprising ferric sulfate and at least one metal impurity, the first sulfate solution having an initial pH;adding a first base to the first sulfate solution in an amount sufficient to raise the initial pH to a second, higher pH of from about 2 to about 5, thereby precipitating ferric hydroxide in a first precipitation step, and forming a ferric hydroxide precipitate and a second sulfate solution;adding an oxidant and a second base to the second sulfate solution formed in the first precipitation step in an amount sufficient to raise the second pH to a third, higher pH of from about 6 to about 10, thereby precipitating at least one metal impurity in a second precipitating step, and forming a third sulfate solution and a metal impurity precipitate; andseparating the precipitated ferric hydroxide from at least one of the second sulfate solution or the third sulfate solution.