Common Mineral Processing Methods
1. Gravity Separation
Principle: Utilizes differences in mineral density and settling velocity; employs water flow or airflow to separate lighter minerals from heavier ones.
Applicable Ores: Gold, tungsten, tin, manganese, lead-zinc, placer deposits, and rare metal ores.
Common Equipment: Jigs, shaking tables, spiral chutes, centrifugal concentrators, and heavy media separators.
Advantages: Low cost, non-polluting, requires no chemical reagents, and features simple operation.
Disadvantages: Poor separation efficiency for fine-grained particles; best suited for coarse-to-medium-grained ores.
2. Flotation Separation
Principle: Relies on differences in the hydrophobic and hydrophilic properties of mineral surfaces; chemical reagents are added to modify surface characteristics, and upon aeration, valuable minerals attach to air bubbles and float to the surface for separation.
Applicable Ores: Copper, lead-zinc, gold, silver, molybdenum, and polymetallic associated ores.
Common Equipment: Mechanically agitated flotation cells and aerated flotation cells.
Associated Reagents: Collectors, frothers, modifiers, and depressants.
Advantages: High separation precision, excellent results for fine-grained minerals, and the widest range of applicability.
Disadvantages: Requires the use of chemical reagents, necessitates wastewater treatment, and entails relatively higher production costs.
3. Magnetic Separation
Principle: Exploits differences in the magnetic susceptibility (strength) of minerals to separate magnetic minerals from non-magnetic ones within a magnetic field.
Applicable Ores: Magnetite, hematite, limonite, ilmenite, and for iron removal/impurity removal applications.
Classification: Weak magnetic separation, strong magnetic separation, dry magnetic separation, and wet magnetic separation.
Common Equipment: Drum-type magnetic separators, wet magnetic separators, and dry iron removers.
Advantages: Simple equipment design, low power consumption, environmentally friendly (non-polluting), and high degree of automation.
Disadvantages: Applicable only to magnetic minerals; cannot be used for non-magnetic ores.
4. Washing and Screening
Principle: Utilizes the scouring action of water flow and mechanical agitation to wash away soil, clay, silt, and other impurities adhering to the surface of the ore. Applicable Ores: Clay-rich ores, weathered ores, and various raw ores with high mud content.
Common Equipment: Rotary drum washers, trough washers.
Function: Removes mud in advance to prevent equipment clogging and enhance the precision of subsequent beneficiation processes.
5. Electrostatic Separation
Principle: Achieves separation within a high-voltage electric field by exploiting differences in the electrical conductivity of minerals.
Applicable Ores: Titanium ores, zircon, diamonds, and non-metallic minerals.
Features: Primarily used for fine beneficiation and dry separation; frequently employed for the purification of rare minerals.
6. Chemical Beneficiation
Principle: Extracts valuable metals through chemical reactions such as leaching, extraction, and displacement.
Applicability: Low-grade gold ores, oxidized ores, and complex, refractory ores.
Mainstream Processes: Cyanide leaching (for gold), heap leaching, hydrometallurgical gold recovery.
Advantages: Capable of processing refractory ores that cannot be separated using conventional methods.
Disadvantages: Complex processes; imposes extremely stringent environmental protection requirements.
7. Manual Sorting (Hand Picking)
Principle: Relies on visual inspection—distinguishing by color and shape—to manually separate waste rock from valuable ore.
Applicability: Large-lump ores and coarse-grained materials requiring pre-treatment.
Features: The simplest and most primitive method; primarily used in the preliminary stages to remove coarse waste rock.