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Spiral separator

technology Maturity 11-13 Next article →

A spiral separator is a clever tool used for sorting. It can sort things by weight or by shape.

Sluice
Sluice

Some tools use water to do this work. These are called wet spiral separators. They are also known as spiral concentrators. They help sort solid bits in a liquid mix called a slurry. This process is very important for cleaning materials. It helps separate valuable things from waste.

Sluice
Sluice

Wet separators work using a tower and a winding path. This path is called a sluice. It winds around the tower like a spiral staircase.

Sluice
Sluice

The slurry flows down this winding path. Heavy particles sink to the bottom of the sluice. They move slowly toward the center of the spiral. Light particles stay on the outside with the water. They move quickly to the bottom. At the bottom, adjustable bars make a cut. This cut separates the heavy parts from the light parts.

Sluice
Sluice

These tools work best under certain conditions. They often use a slurry that is 20% to 40% solids. The particles are usually between 0.75 and 1.5mm in size.

Sluice
Sluice

This size is also called 17 to 340 mesh. The machine is less efficient with very tiny particles. These are between 0.1 and 0.074mm. For the best results, the heavy minerals must be much denser. The density difference should be at least 1 g/cm3. The particles also work best if they have a uniform shape.

Sluice
Sluice

People can do many things to make these machines work better. They can change how much material they feed in. They can also change the grain size of the material. Some people add washwater along the path to help. Others add ridges to the sluice at an angle. These ridges help the separation happen. A single machine can process a couple tons of ore per hour.

Sluice
Sluice

You can even stack multiple flights to increase capacity.

There is also another kind called a dry spiral separator. This type sorts things by their shape instead of weight.

Sluice
Sluice

It has a tower with an inward path. A funnel sits around this path to catch things. Round particles roll much faster than other shapes. They fly off the path and into the collection funnel. Other shapes are not round enough to fly off. They stay on the path and go to the bottom. This helps remove weed seeds from a harvest. It can also remove deformed lead shot.

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