Abstract: Disclosed is a process for separating gold from acidic solutions having a pH below about 3 which comprises the steps of:(a) adding a sufficient amount of the sodium salt of 2-mercaptopyridine-N-oxide to cause at least a portion of the gold in the aqueous acidic solution precipitate from the solution; and(b) separating the precipitated gold from the acidic solution.Also disclosed is that gold is selectively precipitated from acidic solutions containing other metals [e.g., Fe, Cu, Zn, Sn] when the molar ratio of added sodium 2-mercaptopyridine-N-oxide to gold in the acidic solution is less than about 1.5:1.

Abstract: Disclosed is a process for separating precious metals such as gold or platinum from acidic solutions having a pH below about 3, which comprises the steps of:(a) adding a sufficient amount of a heavy metal chelate (e.g., zinc or iron) of 2-mercaptopyridine-N-oxide to the acidic solution to cause at least a portion of the precious metals in the solution to transchelate with the heavy metal chelate of 2-mercaptopyridine-N-oxide and then to form precipitates in the solution; and(b) separating the precipitated precious metal chelates of 2-mercaptopyridine from the acidic solution.