Mill with balls

A crushing mill with balls also called with balls is an apparatus intended to grind very fine powder solids. It is used in particular in Peinture, Pyrotechnie, Céramique,…

Description

A mill with balls is composed of a horizontal Tambour put in rotation by an engine. One fills it partially of the product to be ground then one adds the elements of crushing (metal balls, Galet S of Silex,…). Once the Rotation launched, a phenomenon of Cascade crushes the substance to be ground in a fine powder. Naturally so that this phenomenon occurs, the number of revolutions should not be excessive: the bodies inside the drum should not be plated against the wall by the Centrifugal force.

The industrial mills can function uninterrupted: they charged at an end and are discharged with the other. The imposing models are motorized by their axis while the more modest drums are deposited on cylinders in rotation.

The mills of high-quality can be very expensive, but they make it possible to reduce solids in particles of 0,0001mm what increases external surface and improves the rates of reaction.

Elements of crushing

There exists a great number of different substances, each one having its advantages and its disadvantages. One finds regularly balls of Stainless steel: their effectiveness is due to the strong density of this metal and relative the " inertie" stainless which does not contaminate too the products to be crushed. However, certain applications require particular balls:
  • in Pyrotechny, the balls should never spark: one thus employs Cuivre, Bronze or a Alliage of Plomb and Antimoine;
  • in Ceramic, the Fer can deteriorate certain rough materials: one then uses ceramics or flint rollers;
  • in Chemistry, when one crushes a corrosive product : one also makes use of ceramics rollers.

Remarks

  • Certaines mineral techniques of Polissage of uses similar machines but the substance of crushing is replaced by a product Abrasif;
  • In pyrotechny, the mill with balls can be employed only for proyer of the powders nonsensitive to the Friction.

See too

Internal bonds

External bonds

  • Mill with ball on PyroGuide

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