Recycling placer platinum
25 December 2012

Placer platinum is a heterogeneous mixture of grains of platinum, rock and rock and osmiridium. One of our services is the process of placer platinum to extract precious metals.

Placer platinum contains a high amount of platinum, with some non-ferrous metals and sulfur. Accordingly, processing this material is fairly simple. The following steps are following during the processing of placer platinum: dissolution, conditioning of the solution and sedimentation of platinum-group metals. The platinum solution is repeatedly treated in aqua regia, in order to convert it into chlorides.

The undissolved sediment and osmiridium is smelted with zinc in an electric furnace at a temperature of 700 to 800 °C. After the alloy has cooled, it is crushed and processed in order to recover the zinc. The remaining material, along with barium peroxide, is subjected to a temperature of 1000 °C, which causes platinum oxides to appear in the acid. After treatment with hydrochloric acid, all of the metals apart from osmium,will dissolve. The metal dissolves at temperatures ranging from 100 to 130° C, with constant stirring. Mixing is carried out by mechanical stirrers.

First, the placer platinum is extracted from the solution, using sulfur dioxide and gold. All undissolved residues remaining after the recovery of the placer platinum are sent for extraction of other metals, including osmium, rhodium, iridium and ruthenium. In order to recover these metals,the residue, together with the barium peroxide, is subjected to temperatures of 700 to 800 °C , after which the sintered material is crushed and treated with hydrochloric acid.

The amount of residue typically ranges from 4 to 6% of the total mass of the placer platinum. This residue will usually contain some ruthenium and palladium, 12% osmium, 3% rhodium and 10% platinum.