Company Announcement - Modular process enables high direct recoveries with low inventory, has a low environmental impact, and can be adapted for a wide variety of applications. The result of decades of experience and continuous development in precious metals processing technology, the Outotec Hydrometallurgical Precious Metals Process was originally developed for the treatment of anode slime generated in copper electrorefining. Its cost-effective, modular approach can be adapted for a variety of different applications and can also be combined with other precious metals technologies such as the Outotec Selenium Roasting Furnace, Outotec TROF, or Kaldo Furnace.

The process ensures effective separation of impurities with high recovery. Impurities can be converted into saleable products such as selenium, copper telluride, and lead sulfate to improve operational profitability. The recovered silver and gold are of a high grade and are melted and cast into ingots or granules. Operation is straightforward, with the process comprising simple leaching, filtration, and precipitation steps that are either sulfuric or hydrochloric acid based. The chemicals used do not form highly toxic compounds and can be mostly recycled for reuse within the process. This reduces both waste water volumes and fresh water consumption.
Effective off-gas cleaning not only improves working conditions and reduces environmental impact, it also improves precious metals recovery by allowing any metal traces that remain as droplets in off-gases to be captured.

Key benefits
• High direct recovery and high end-product quality with low inventories
• Quick process with high level of automation to enable consistent end-product quality and smooth operation
• Flexible and cost-efficient modular process design
• Recovered impurities can be sold as by-products instead of being disposed of
• Low environmental impact with no flue dust or slag generation