The scrubbing & attrition

Scrubbing aims to suspend all solid elements present in the material to be treated, often clay or not hardened, using constituent dispersion phenomena through deconsolidation and disintegration. It also involves the more or less comprehensive surface washing of elements, or the dissolution of salts and any compounds present.

The equipment used are scrubbing drums made up of a cylindrical body turning around a horizontal axis fitted with lifters. They usually include an output trommel screen enabling the coarse particle to be separated directly from the output.

Attrition is intended to comprehensively clean the surface of particles in the event that particles are covered with harmful foreign bodies: encrusted oxides, hydrocarbon film, surface roughness trapping very fine carbon or metallic particles, presence of very crumbly foreign constituent parts, etc. This operation is carried out by rubbing particles together in attrition cells.

These cells are made up of a tank and a rotor with opposing directional helix rotor blades, whose rotation creates very intense swirling cells within which the particles to be treated crash into one another and rub against one another.

The material to be treated is 65-75% pulp solids to maximise particle-particle contact. Attrition can only be performed on a range of particle sizes from 50…100 µm to 6…7 mm.

SCRUBBING
Type	Diam./Length	Trommel screen	Particle size In (d100)	Capacity
Proceptis DSF	800/1500 mm	30 mm	60 mm	0.5-1 t/h
Improve	1200/3700 mm	4 mm	80 mm	1.2 t/h
ATTRITION
Type	Diam./Length	Trommel screen	Particle size In (d100)	Capacity
Wemco (lab)	1	1010 rpm	100 µm to 7 mm	1.5 litres
Wemco (pilot)	2	445 rpm	100 µm to 7 mm	2 x 30 litres
Denver Sala 16 x 16	2	575 rpm	100 µm to 7 mm	2 x 85 litres