How do spiral concentrators separate heavy mineral particles from lighter ones?

Spiral concentrators are used in mineral processing to separate fine-grained particles, typically ranging from 1 millimeter to 50 micrometers in size. These devices consist of a vertical spiral channel with an oval cross section.

As the ore pulp flows from the top to the bottom of the channel, the system utilizes centrifugal force to assist in the separation process. Due to the differences in density, the heavier mineral particles are directed toward the inner side of the stream. Once concentrated in this inner area, the heavy particles are removed through specially designed openings in the channel. This method is particularly effective for concentrating gold ores and heavy mineral sands because of its simplicity and low energy requirements.1