Platinum Group Metal Recycling

Recycling Platinum Group Metal Alloy Scrap
Platinum group metal (PGM) alloys come in many forms as scrap. Occasionally, factories collect scrap from a single source with a consistent composition. This material may only suffer from surface contamination or physical damage during use. Workers can often reprocess it into new parts after simple cleaning. For example, they remove oil and carbon deposits through high-temperature oxidation, dissolve base metals with boiling acids (hydrochloric, sulfuric, or nitric), and eliminate silicon using alkalis or hydrofluoric acid.

Most scrap, however, comes from mixed sources with varying compositions. Recyclers must first dissolve the material, separate impurities, isolate individual platinum metals, and refine them to achieve purity.

Recovering Pt-Pd-Rh Catalytic Nets
Ammonia oxidation towers rely on Pt-Pd-Rh alloy nets, typically containing Pt-4Rh-3.5Pd (ternary) or Pt-(5-10)Rh (binary). Chinese manufacturers often use a quaternary alloy (Pt-Pd-Rh-M) with extra palladium and another active metal (M). Factories draw these alloys into thin wires (0.06–0.09 mm) and weave them into nets.

Over time, high-temperature oxidation causes platinum and rhodium to vaporize, leaving behind weak, porous "cage structures" on the wire surfaces. Trace base metals also contaminate the nets, reducing their catalytic activity. When performance drops, recyclers recover the metals to produce fresh catalytic nets.