Antimony (Sb) is an important strategic metal, widely used in flame retardants, alloys, semiconductors, and other fields.
There are several main types of antimony ores:
- Stibnite: This is the main ore of antimony, with a chemical composition of Sb₂S₃. Stibnite is usually silver-gray with a metallic luster and is common in hydrothermal deposits.
- Jamesonite:This ore contains antimony and other elements, with a chemical composition of Pb₄FeSb₆S₁₂. Its content in the ore is relatively low.
- Other antimony ores:It also includes some antimony-containing ores, such as antimony-lead ore.
Antimony extraction is usually separated and extracted from antimony ore through processes such as ore dressing and smelting. In terms of environment and safety, antimony and its compounds may be toxic to a certain extent, so safety measures need to be taken when handling and using them.
Antimony sulfide ore (stibnite, Sb₂S₃) is the most important antimony mineral, and its beneficiation methods mainly include flotation and gravity separation. However, some beneficiation plants are limited by the nature of the ore, environmental protection requirements, or economic costs, and cannot use flotation technology. In this case, gravity separation technology has become a key technology for the efficient recovery of antimony concentrate.
Antimony Sulfide Ore Gravity Separation
Antimony sulfide ores (stibnite) are usually recovered by flotation. Still, in some cases (such as fine-grained, highly muddy ores, environmental restrictions, or cost considerations), gravity separation becomes the preferred choice. Compared with flotation, gravity separation has the following advantages:
- No flotation reagent is required.
- Applicable to coarse-grained antimony ore, and can efficiently recover high-grade antimony concentrate.
- Strong adaptability, can process antimony ore with high mud content or low oxidation rate.
Antimony Sulfide Ore Gravity Separation Process
1. Crushing stage
Coarse crushing: Use a jaw crusher to crush the raw ore to 50~100mm.
Medium and fine crushing: Use a cone crusher or impact crusher to further crush the ore to 10~20mm to provide a suitable particle size for grinding.
2. Ball mill closed-circuit grinding
Grinding equipment: Use a ball mill to form a closed-circuit grinding system with a spiral classifier or hydrocyclone.
Grinding fineness control: The target particle size -0.074mm (200 mesh) accounts for 60%~70%, ensuring that the antimony ore is fully dissociated.
Closed-circuit circulation: The coarse particles that do not meet the standard are returned to the ball mill for re-grinding to improve the grinding efficiency.
3. Spiral chute roughing
Equipment selection: Use a glass fiber reinforced plastic spiral chute, with a processing capacity of 2~4t/h·unit.
Separation principle: Utilize the difference in mineral density. Under the action of spiral water flow, high-density antimony minerals are concentrated on the inner edge, and low-density gangue is discharged to the outer edge.
Roughing effect: A rough concentrate with an antimony grade of 20%~30% can be obtained, and most of the tailings can be discarded.
4. Shaking table separation
Equipment selection: Use a 6-S shaking table, with a processing capacity of 0.5~1t/h·unit.
Separation principle: Combine bed vibration and lateral water flow to further separate antimony minerals (density 4.6~4.7g/cm³) from gangue.
Separation effect: Finally, high-quality antimony concentrate with an antimony grade of ≥45% is obtained, and the recovery rate can reach 70%~80%.
Optimization of key process parameters
| Process | Key Parameters | Optimization Suggestions |
| Crushing | Final particle size | Control at 10~20mm to avoid over-crushing |
| Grinding | Fineness | (-200 mesh ratio) 60%~70% to ensure the dissociation of antimony minerals |
| Spiral chute | Feed concentration | 25%~35% to improve sorting efficiency |
| Shaking table | Stroke and stroke times | Adjust to the best mineral stratification state |
Guide to Optimization of Gravity Separation Process for Antimony Sulfide Ore
Key points of gravity separation for antimony sulfide ore
1. Analysis of ore properties and gravity separation adaptability
- Density characteristics: Sb₂S₃ density (4.64 g/cm³) is higher than gangue (quartz 2.65 g/cm³, calcite 2.7 g/cm³), which has a good basis for gravity separation.
- Particle size influence:
+0.074mm particle size: high-efficiency recovery by jigging and spiral separation
-0.074mm particle size: centrifugal separation or shaking table fine recovery is required - Embedding characteristics: coarse dissociated ore (>0.2mm) is suitable for direct re-selection; fine embedded ore needs to be pre-ground to a suitable degree of dissociation.
2. Gravity separation process design
The typical gravity process includes four stages: pre-selection - roughing - concentrating - scavenging. It is recommended to use the combination of "jigging + shaking table" or "spiral separation + centrifugal separation".
| Stage | Recommended equipment
|
Process parameters | Effect indicators |
| Pre-selection | X-ray sorter / photoelectric concentrator | Waste rate 20-30% | Reduce subsequent processing volume |
| Roughing | Sawtooth wave jig | Stroke 8-12mm, stroke 300-350 times/min | Recovery rate>85% |
| Cleaning | 6-S shaking table | Bed slope 2°-5°, stroke 12-16mm | Concentrate grade ≥55% Sb |
| Scavenging | Centrifugal concentrator | Speed 800-1200rpm, backwash water pressure 0.1MPa | Tailings Sb<0.3% |
Optimization suggestions:
- Jig-shaker combined process: suitable for medium-coarse antimony ore, with a concentrate grade of more than 60%.
- Spiral-centrifugal combined process: suitable for fine-grained ore (<0.074mm), reducing metal loss.
3. Key influencing factors and optimization measures
- Feed particle size control: crushing to -2mm accounts for >80%to ensure effective dissociation of minerals.
- Slurry concentration adjustment:25-35% solid concentration, too high affects stratification, too low reduces recovery rate.
- Equipment parameter matching:
Jig separator: Adjust stroke and stroke times to control the looseness of the ore bed.
Shaker: Optimize the lateral slope and flushing water volume to increase the concentrate enrichment ratio.
4. Gravity separation vs flotation comparison
| Indicators | Gravity separation process | Flotation process |
| Recovery rate | 70-90% (depending on the nature of the ore) | 85-95% |
| Concentrate grade | 50-60% Sb | 55-65% Sb |
| Environmental protection | No reagents, zero pollution | Yellow medicine/black medicine required |
| Investment cost | Reduced by 30-40% | High |
| Applicability | Coarse-grained easy-to-separate ore | Fine-grained or complex ore |
Conclusion
The gravity separation process is suitable for antimony sulfide ores that cannot be floated, and can stably produce antimony concentrates above 45 degrees. The gravity separation process is particularly suitable for antimony ore dressing plants with coarse grains, environmental sensitivity, and low investment requirements. The combination of spiral chute + shaking table can efficiently enrich antimony ore, with a recovery rate of 70%~80%. Reasonable optimization of parameters such as grinding fineness and feed concentration can further improve the separation index, with a recovery rate of more than 85% and a concentrate grade of >55% Sb. The future development direction can be combined with the "gravity separation + flotation" joint process to improve resource utilization further.