In the solvent extraction process phase, metal in the pregnant leach solution (PLS) is concentrated and purified into electrolytes. The pure electrolyte is then used in electrowinning to produce a chemically and physically high-quality product.
Outotec is the only technology provider that offers a highly predefined but still tailor-made total delivery package based on your needs. Our renowned SX knowledge is integrated in the innovative Outotec VSF® X mixer-settler modules. This environmentally friendly and sustainable product is available with fast-track delivery, predefined costs, state-of-the-art documentation and implementation, efficient logistics, and fast installation.
The modular system is flexible in terms of capacity, as more can be added while the plant is up and running by increasing additional lines of sections. Soil contamination of each mixer-settler is completely avoided and possible leaks are easy to detect and repair. Furthermore, the settlers have additional value since they are easy to disassemble and transport to a new site.
The SX equipment (Outotec DOP® units, Outotec SPIROK® mixers, settlers, loaded organic tanks, and after settlers) come together to enhance the stability of the process against organic phase oxidation and improve work safety by minimizing organic evaporation. Fire safety is also maximized due to the low oxygen presence and limited combustion space. There are no carbon steel parts inside the equipment, which also reduces fire risks during maintenance.
VSF® X DOP Unit
Pumping and mixing are separated in the solvent extraction technology. This ensures low entrainment losses even if flows have to be increased above the design values for operational reasons. The DOP unit consists of a suction tank with a conical overflow rim, a turbine, a flow stabilizer, and a baffled cylindrical outer tank.
VSF® X SPIROK Mixer Unit
The mixer unit is designed to ensure the gentle and uniform mixing needed for proper dispersion mixing. Even at low rotation speed a vertical flow is maintained throughout the whole mixer. The Outotec SPIROK mixer covers the entire volume of the mixer tank, which avoids local high shear forces and contributes to optimizing residual organic and aqueous entrainment levels.
VSF® X Settler
The settler design is very important for solvent extraction plant operation. The Outotec VSF® X Settler has a deep, dense, and packed dispersion layer at the feed side of the settler. The incoming dispersion flow is evenly distributed with a feed launder. Dispersion is then kept at a compressed state by means of Outotec DDG® separation fences. The dense dispersion layer filters small droplets and enhances coalescence. More flexibility to handle higher feed flows is achieved when the dispersion and the separated organic phase are not allowed to spread over the whole settling length. The separated organic and aqueous phases are finally collected into separate launders. The aqueous inner circulation is taken from the settler bulk without disturbing the flows inside the settler.
Health, safety, and environmental (HSE) aspects are an inseparable part of the plant concept. They are taken into consideration during the product definition phase, providing a safe and sustainable plant that is easy to operate and maintain. The plant concept offers:
- Possibility to use sea water as process water
- Waterlocks in the inspection/maintenance hatches
- Minimized VOC emissions
- Minimized energy consumption
- Reduced plant area with reduced excavation costs
- Minimized environmental impact and carbon footprint
- The safest available technology for operators
- Mixer-settlers with a high residual value