Ore Dressing Equipment Spiral Chute Gravity Separation

Ore Dressing Equipment Gravity Spiral Chute Separator

The beneficiation equipment produced by our company includes filter press, floatation equipment, floatation equipment and spiral chute separator, etc. This chapter takes us to quickly understand a mineral processing equipment - spiral chute separator. Spiral chute separator is used to achieve separation on the basis of differences in specific gravity between the various minerals, usually a wet process, although examples of dry gravity separators exist. Gravity separation works best when the minerals are separated by large differences in specific gravity, the particles are of similar size, not overly fine, and are round in shape. 

Spiral chutes are typically used to separate sand-sized particles, with a gravity differential of 75 microns in the -2mm range, and can separate reasonably efficiently down to 38um. Below this size range the efficiency falls off rapidly, raising the general requirements for fine ore gravity separators. The smooth surface of the spiral chute is made of polyurethane molded over fiberglass that forms a spiral trough. Helix type, groove profile and pitch as well as height and diameter and number of turns can vary according to function. The feed slurry is at the top and is subjected to a combination of gravitational and centrifugal forces imparted by the spiral motion below it. This will cause the high gravity minerals to flow towards the trough, the water and the low gravity mineral center towards the outside world. The isolated slurry is thus discharged from the screw at the bottom and high gravity (concentrated) and low gravity (tailings) can be separated together with intermediate gravity (medium).

The choice of screw depends on: coarse/cleanness; feed grade: low/medium/high, and particle size: sand/fine powder. Usually the feeding type of the spiral chute is coarse, which is easy to separate and has a large total throughput, and the design of triple or quadruple reduces the area and high capacity. Clean and fine spiral chutes have less overall throughput and separation difficulties and are usually operated at lower feed rates. A cleaning spiral chute is also available with wash water.

Operating variables include:

Feed rate (1 to 6 tons per hour)

Feed density (25% and 50% solids)

separator location