In industries working with gold or other precious metals, after the parts have been cleaned, the wash water contains small particles of these materials. To recover them, a physico-chemical treatment is used: chemical agents are added to the wastewater to precipitate the precious metals in the form of solid compounds, which can then be filtered and recovered.
In addition, our equipment is designed with advanced mechanical precision to optimize and maximize precious metal recovery. Each component is specially designed to ensure maximum efficiency in the recovery process, minimizing losses and guaranteeing high yields. Thanks to this advanced engineering, our systems enable increased recovery of precious resources, meeting the high demands of industries that value quality, sustainability and profitability.
The stages involved in recovering gold and other precious metals
1. Decomplexation
Sometimes, gold and other precious metals in wash waters are in dissolved form, bound to other substances (known as metal complexes). Decomplexation involves adding chemicals to break down these complexes and release the metals in solid or particulate form. This makes them recoverable. The aim is to transform dissolved metals into solids.
2. Coagulation
Chemicals (coagulants) are added to the water to make the small metal particles stick together. This neutralizes their electrical charge, preventing them from repelling each other.
3. Flocculation
After coagulation, another product (flocculant) is added to make the particles swell to form flocs, large clumps that are easy to separate from the water. These flocs may contain particles of precious metals, such as gold.
4. Filter press
Once the flocs have formed, the water passes through a filter press. This system uses high pressure to force the water through filter plates, trapping solids, including precious metal flocs.
In the end, precious metal-rich sludge “cakes” are obtained, which are then processed to extract gold or other metals.
In summary, these steps maximize the recovery of precious metals in industrial wastewater treatment:
- Decomplexation: Releases dissolved metals.
- Coagulation & Flocculation: Coagulates small particles so that they separate more easily.
- Filter press: Effectively separates water from solids and recovers precious metals in the form of sludge.
If you are based in France or Switzerland and need a solution for the treatment of your industrial water, contact our NGL Water Technology teams
