Dry Material Separations

How is fluidizing air and controlled vibration used to separate a dry mixture? Using tuned airflow to strategy the material?
The lighter materials are lifted from the deck surface and allowed to float down the inclination of the deck. Heavier particles are in closer contact with an inclined vibrating surface. This vibration actually moved particles on the surface up the incline, opposite the lighter material not in contact with the vibration.

What is the most efficient way to accomplish separation?
First, you will want to screen the particles into manageable size ranges prior to separation. Where significant variations in shape are found to be detrimental to separation efficiency, size reduction or other process steps to change the shape may be added to reduce the range of variation. Moisture reduction may also be key to effective separation. Some materials absorb moisture and weight, others are complicated by the ‘sticky factor.’

What is the difference between the different models?
In general, there are two different model classifications, rectangular two-way separations and triangular offering a gradient of density out. The rectangular shape is commonly called a stoner. The triangular shape is commonly referred to as a gravity separator or air table.

When should I use a gravity separator?
The triangular shape, or trapezoidal, produces a fan or range of density output allowing one or more intermediate density fractions or “middlings.” In some processes, the middling fraction allows further separation efficiency by allowing other processes. This can be recycled intro further density separation.

When should I use a stoner?
It is used when separation of a smaller amount of dense material from a lighter product. The name is derived from separations of contaminants from agricultural products, but density separations cross into mineral, chemical and many other areas. A stoner may have a higher capacity and lower operator attention requirements, but offer less flexibility and precision.