US 5,393,389 AGranted

Electrolytic process for obtaining high purity platinum from contaminated platinum

AssigneeSchott Glaswerke

InventorsSigrid Herrmann, Uwe Landau

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Abstract

The electrolytic process for obtaining platinum of high purity from a concentrated hydrochloric acid solution of contaminated platinum containing base and noble metal impurities includes electrolyzing the hydrochloric acid solution containing the contaminated platinum in an electrolysis cell subdivided by a cation exchanger membrane under potentiostatic or voltage-controlled conditions with a voltage of 2.5 V to 8 V applied across the anode and cathode under a current density of 0.3 to 12.5 A/dm.sup.2 so as to form a refined platinum-containing solution and a platinum alloy metal deposit. The concentrated hydrochloric acid solutions used in the process can have a contaminated platinum content of 50 to 700 g/l and total metal impurities of .ltoreq.5000 ppm. In contrast to the known prior art processes, the process according to the invention operates with minimal requirements in terms of safety technology and equipment, causes a minimal environmental burden and is far less time-consuming and more economical.

Claims16

Dependent claims

Electrolytic process for obtaining platinum having a high purity from a concentrated hydrochloric acid solution of contaminated platinum containing noble and base metal impurities, said process comprising the steps of:

a) providing an electrolysis cell comprising an anode compartment containing an anode and the concentrated hydrochloric acid solution of the contaminated platinum as anolyte and a cathode compartment containing a cathode and a 6 to 8N hydrochloric acid solution as catholyte, said anode compartment being divided from said cathode compartment in said electrolysis cell by a cation exchanger membrane;
b) electrolyzing said hydrochloric acid solution of said contaminated platinum in said electrolysis cell under voltage-controlled conditions by applying a voltage of from 2.5 V to 8 V across said anode and said cathode at a current density of from 0.3 to 12.5 A/dm.sup.2 to form a refined platinum-containing solution and a platinum alloy metal deposit;
c) recovering said platinum alloy metal deposit;
and
d) obtaining said platinum of high purity from said refined platinum-containing solution.

2 more elements

Dependencies are inferred from the claim text.