A method of refining and recycling iridium

A method of refining/recycling iridium, the method comprising:

• adding, in a first precipitation vessel, ammonium chloride to an iridium containing refining/recycling solution comprising iridium dissolved in hydrochloric acid to precipitate ammonium hexachloroiridate;
• filtering the precipitated ammonium hexachloroiridate;
• washing the filtered ammonium hexachloroiridate with a wash mixture of ammonium chloride and water;
• and
• recycling the wash mixture of ammonium chloride and water back into a second precipitation vessel, which may be the same vessel as the first precipitation vessel or a different precipitation vessel, to recover any iridium dissolved in the wash mixture during washing of the ammonia hexachloroiridate,
• wherein the recycled wash mixture is mixed with another portion of the iridium containing refining/recycling solution in the second precipitation vessel to precipitate ammonium hexachloroiridate, wherein the ammonium chloride is added to the iridium containing refining/recycling solution in an amount sufficient to provide ammonium ions in excess of iridium, the recycled wash mixture providing at least a proportion of the ammonium ions thus reducing or eliminating the requirement for addition of fresh ammonium chloride to achieve excess ammonium ions.