Please Note: Blog posts are not selected, edited or screened by Seeking Alpha editors.

Purification of Platinium, Gold Refining Emakmakina.com

Purification of Platinium
 
 
Waste or scrap is solved in aqua regia, just like we treat gold.
It is filtered to separate silver chloride.
It is precipitated using gold sulfite or iron sulphate. It is filtered and taken out.
Metallic zinc powder is added to the remaining solution and palladium and all other metals, including copper, are precipitated. They are filtered and washed thoroughly.
Hydrogene peroxide is added slowly to the sulphuric acid dilluted 50-50 with water, and is mixed until the reaction is completed. Zinc and copper go into the solution. What remains at the bottom are palladium, platinium and other platinium group elements. They are washed thoroughly.
In order to separate palladium, it is boiled in nitric acid. Palladium goes into the solution. Platinium, rhodium and iridium remain at the bottom. It is washed and taken away.
The solution containing palladium is once again precipitated using zinc, washed, the excessive zinc is taken away using sulpruric acid, and it is melted.
In order to separate platinium (if there are rhodium and iridium), it is boiled in aqua regia and filtered. What remains at the bottom are rhodium and iridium. Platinium is once again precipitated using zinc, and the excessive zinc is taken away using sulphuric acid, washed and melted using oxygen flame.

Reference: Emak Gold Refining Machines
                   Purification of Platinium Gold Refining Forum