Most of the chrome ores around the world are beneficiated by gravity concentration techniques. A conventional chromite ore beneficiation process plant (as following Figure) consist of two sections:
1.Communition (for preparing the material for the subsequent unit operations)
2.Concentration (classification and beneficiation).
The beneficiation process flow sheet varies from location to location according to the ore characteristics. For example, the chrome ore plant in Inner Mongolia comprises three stages: crushing (jaw and cone crushers) followed by two-stage grinding (rod mill and ball mill), followed by a combination of drum, cone, and highgradient magnetic separation. In Sichuan province, chromite concentrators consist of gravity separation (spiral chutes and shaking tables) for coarse chromite fractions and a combination of gravity separation and flotation for fines.
Performance of gravity concentrators
A typical chromite ore gravity concentration circuit comprises various configurations of hydrocyclones and spirals or floatex density separators combined with two or more stages of spiral circuit (typically roughing, cleaning, and recleaning) to overcome the inefficiencies created by the random misplacement and/ or bypass of particles. The selection of gravity concentration units is based on the particle size to be treated and the capacity, which is inversely proportional to particle size.