The refinery receives the 98%+ silver doré bars from the cupel, and utilises a number of moebius cells to convert the doré to 99.99% silver.
The cells contain titanium mesh baskets, which act as the anode, into which the bars are placed. The baskets are submersed in an acidified silver nitrate electrolyte. A dc current is applied which causes the silver ions to migrate and deposit as crystals of silver on the cathodes.
The crystals are detached from the cathode by periodic automatic mechanical scraping, removed from the cells and are then washed in de-ionised water and dried.
Gold and platinum group metals in the form of anode slimes, are collected in fabric bags, and these are dried, milled and sampled and subsequently refined in a separate process.
The silver crystals are melted and cast into 1000 troy ounce 99.9% silver 'Good Delivery' bars.
See Schematic Process Flow Chart