Attrition is a physical process that involves the reduction of particle size due to friction and rubbing between them, generally in a wet or dry environment. This mechanism is used in mining and metallurgy mainly for the cleaning or release of finely adhered minerals or for the controlled reduction of softer and more fragile particles.
Main characteristics of attrition
- Mechanism: It is based on surface wear caused by the interaction between particles or between particles and solid surfaces of equipment.
- Common applications:
- Cleaning of mineral particles to remove clays or surface contaminants.
- Release of fine gangue particles adhered to valuable minerals.
- Reduction of particle size without completely fracturing them.
- Working media: Normally, water slurries with suspended particles are used in drums or attrition cells.
Equipment used for attrition
1. Attrition drums:
- They consist of rotating cylinders where the particles are agitated and worn.
- Effective for coarser materials and where intensive cleaning is required.
2. Attrition cells:
- Specialized equipment with propellers or agitators that generate the necessary friction.
- Suitable for finer particles and for flotation cleaning operations.
Advantages of attrition
- Improved quality: Cleans particles, improving their response in stages such as flotation or magnetic separation.
- Selective reduction: Abrades soft materials, leaving valuable minerals intact.
- Operational efficiency: Promotes the overall performance of downstream processes by removing impurities.
Examples of uses for attrition
1. Sand and gravel mining:
- Removes clay coatings on sand grains to produce purer material.
2. Phosphate processing:
- Cleans phosphate particles to increase their quality before flotation.
3. Beneficiation of metallic minerals:
- Prepares valuable minerals (gold, copper, etc.) by liberating fine gangue particles.
