Boratas spiral classifier is a machine that is mainly used to separate slimes from sand and sandy-sized materials. The resulting products are the underflow which is a partly dry fraction containing the rough material and the overflow which is a fine fraction along with what's left of the liquid medium portion. This machine is usually placed at the end of the crushing and screening plant.

This machine is composed of an inclined trough and one or two spirals rotating slowly and not touching either the sides or the bottom of the tank. This tank contains a pool of fluid pulps and is designed to permit coarse solids to separate from the water and impurities, whereafter they are taken out by gravity, mechanical ways, or pressure. The solids which aren't separated are called overflow as stated above.

The spiral classifiers are very robust, versatile, and easily maintained resulting in low operating and maintenance costs.

Characteristics of the Spiral Classifier:

• Low initial cost
• Low operating and maintenance cost
• Simple flexible lifting device
• Replaceable wearing shoe
• Sectionalized steel flights