Gravity preconcentration method

The gravity preconcentration method, which is used mainly for recovery of gold from placer deposits that contain coarse native gold. Gravity is often used in combination with flotation and/or cyanidation. 

There are three main methods used for beneficiation of tin ores (a) physical concentration including gravity concentration, magnetic separation and electrostatic separation (b) flotation and (c) a combination of gravity preconcentration and flotation. 

The principal method for beneficiation of Ta/Nb ores is gravity concentration. In principle, most of the Ta/Nb ores contain low-specific-gravity minerals of about 2.8-3.0 specific gravity (SG) (quartz, calcite, aluminosilicates, feldspar, etc.), whereas heavy minerals (Ta/Nb and other Ta/Nb mineral carriers) have SGs of 4-4.4, which is suitable for gravity preconcentration. 

A large portion of titanium minerals (ilmenite, rutile) are produced from heavy mineral sands using physical preconcentration methods including gravity, magnetic and electrostatic separation. Over the past 30 years, advances have been made using flotation, where ilmenite, mtile and perovskite can be effectively recovered from both heavy mineral sands and hard rock ores using flotation methods. 

In the past, most of the rutile was produced from heavy mineral sands using physical concentration, involving gravity, magnetic separation and electrostatic concentration. The physical preconcentration method cannot be applied to a fine heavy mineral sand or hard ore. In some cases, heavy mineral sand contains zircon, tantalum, niobium and other heavy minerals, where in most cases a flotation method is used. 

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