5. Contamination due to grinding

Traditionally, contamination during fragmentation operations results from tool wear. Wear products can be troublesome in several ways. They may be colored, abrasive or contain agents prohibited in the end use. They can also poison surfaces by precipitating on them (iron hydroxides).

Contamination can be limited:

• by adjusting line parameters such as speed, flow rate, fill rate, and quantitative ratios of solid/solid + water and solid + water/grinding bodies;

• by adapting the nature of the grinding bodies, linings and stirring elements to each case. They can be chosen from the same material as the substance to be ground, or from a material which, in the subsequent process, will produce the same results as the substance to be ground (e.g. iron bodies for grinding ferrites intended for...