1.Ore Pretreatment
The newly mined gold ore has a large particle size. It needs to go through primary, secondary and tertiary crushing in sequence by jaw crushers and cone crushers, reducing the ore particle size to 10-15mm gradually, which lays a foundation for the subsequent grinding process.
2.Grinding Stage
The crushed ore is fed into a ball mill and ground by collision with steel balls to -0.074mm (accounting for 60%-90% of the particle size fraction), achieving full monomer dissociation of gold minerals and facilitating the contact between flotation reagents and the surface of gold minerals. The ground ore slurry is then fed into a spiral classifier to form a closed circuit. The spiral classifier classifies the ground ore slurry by particle size: the qualified ore slurry is sent to the subsequent process, while the coarse-grained ore slurry is returned to the ball mill for regrinding to ensure the grinding particle size meets the standard.
Ball mill 900×1800
Spiral classifier 600×7000
3.Slurry Conditioning and Reagent Dosing
Slurry Conditioning
The ground ore slurry is fed into a conditioning machine, which is used for slurry stirring and reagent mixing before the flotation operation. The slurry concentration is adjusted to 25%-45% to achieve full mixing and uniform conditioning of the ore slurry and flotation reagents, ensuring the uniform dispersion of flotation reagents and effective contact between air bubbles and mineral particles, and creating favorable conditions for the subsequent flotation process.
Conditioning machine 750×750
Reagent Dosing
Modifier: Reagents are added according to ore properties (eg., lime for sulfide gold ore), adjusting the slurry pH value to 8-11 to inhibit gangue minerals and enhance the interaction between gold minerals and collectors.
Collector: It is selectively adsorbed on the surface of gold minerals to make them hydrophobic (e.g., xanthate for sulfide gold ore, which forms a hydrophobic film through reaction with metal ions).
Frother: It reduces the surface tension of water, generating a large number of stable small air bubbles in the ore slurry to serve as carriers for the adhesion of gold minerals.
4.Flotation Separation
The ore slurry with added reagents is fed into a flotation machine for separation. The roughing, scavenging and cleaning operation processes of the flotation machine are flexibly determined according to the actual properties of the ore to achieve efficient separation and enrichment of gold minerals, which is specifically divided into three steps.
Roughing: The ore slurry is stirred and aerated, and gold minerals adhere to air bubbles to form a froth layer. The froth layer is scraped out to obtain rough concentrate (the gold content is initially enriched but contains more impurities).
Cleaning: The rough concentrate undergoes 2-5 stages of cleaning, with a small amount of collector and frother added to enhance the floatation of gold minerals and inhibit impurities, ultimately increasing the grade of gold concentrate to a high level.
Scavenging: The tailings from roughing are fed into a scavenging tank, with reagents added and aeration-stirring conducted to recover residual gold minerals. The scavenging froth is returned to the roughing/cleaning process to further improve the gold recovery rate.
Flotation machine 0.37 m³ per tank with froth launder
5.Concentrate Dewatering
The gold concentrate obtained from flotation is in the form of ore slurry and needs to go through concentration and filtration dewatering in sequence by equipment such as thickeners and filters to reduce the moisture content of the concentrate. Dry gold concentrate is thus obtained, facilitating subsequent transportation, storage and further gold extraction processing.
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