SandTec is designed to recover fines and ultra-fines present in the slurry coming from aggregates washing plants. Compactness is one of the key feature of SandTec, which has been conceived for uses in which the feeding material oversize is minimum. It guarantees the recovery of about 90% of fines over 75 microns, the almost total elimination of clay and lime impurities, the recovery of materials with a residual moisture below 15% and the reduction of the solids presenting the discharge water with reduction of materials to be treated in the water treatment plants.
Ultra-fines are microscopic particles present in slurry that are typically less than 10 micrometers (µm) in diameter. They can be even smaller, sometimes ranging down to 1 µm or less. Due to their small size, ultra-fines have a large surface area relative to their volume, which makes them highly reactive.
The specific composition of ultra-fines in a slurry depends on the source of the slurry.
- Mining slurries: In mining operations, ultra-fines can be composed of crushed rock, minerals, and clays. Their presence can make it difficult to process and transport the slurry, as they can clog filters and pipelines.
The presence of ultra-fines in slurry can create several challenges, including:
- Reduced flowability: Ultra-fines can increase the viscosity of the slurry, making it more difficult to pump and transport.
- Settlement problems: Ultra-fines can prevent solids from settling out of the slurry, which can make it difficult to separate the liquid from the solids.
- Filtration problems: Ultra-fines can clog filters, making it difficult to remove liquids from the slurry.
- Equipment wear: Ultra-fine particles can be abrasive and can wear down pumps, pipes, and other equipment.
There are a number of techniques that can be used to manage ultra-fines in slurries, including:
- Flocculation: Flocculants are chemicals that can cause ultra-fine particles to clump together, making them easier to settle out of the slurry.
- Coagulation: Coagulants are chemicals that can neutralize the electrical charges on ultra-fine particles, making them more likely to collide and clump together.
- Thickeners: Thickeners are large tanks that allow solids to settle out of the slurry.
- Filtration: Filtration can be used to remove liquids from the slurry. However, ultra-fines can clog filters, so it is important to choose the right type of filter for the application. This is where SandTec comes into play.
