Types of Silica Ore & Primary Uses
Silica ores are categorized into:
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Vein Quartz
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Quartzite
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Quartz Sandstone
Key Applications:
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Metallurgy: Acidic refractory bricks, industrial silicon smelting (SiO₂ >98.5%, 8–100mm granules).
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Chemical Industry: Silicate compounds, sulfuric acid tower fillers.
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Construction: Glass, ceramics, cement.
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High-Tech: Quartz glass, monocrystalline silicon (requires ultra-high purity).
Quartz Sand Classification & Processing
Industrial quartz sand is divided into:
1. Standard Quartz Sand
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SiO₂: 90–99% | Fe₂O₃: 0.02–0.06%
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Process: Crushing → Screening → Washing → Drying
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Uses: Glass, ceramics, metallurgy, silicon carbide.
2. Refined Quartz Sand (Acid-Washed)
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SiO₂: 99–99.5% | Fe₂O₃ ≤0.005%
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Uses: High-grade glass, refractories, acid-resistant concrete.
3. High-Purity Quartz Sand (HPQS)
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SiO₂ ≥99.95% | Fe₂O₃ ≤0.001% | Al₂O₃ ≤0.01%
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Process: Magnetic separation → Flotation → Acid leaching → Baking
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Uses: PV crucibles, semiconductors, fiber optics, aerospace.
4. Silica Powder
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Production: Grinding → Floatation → High-purity water treatment
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Properties: High thermal resistance, insulation, low expansion.
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Uses: Electronics, coatings, advanced ceramics.
Industry-Specific Quartz Sand Applications
A. Panel-Grade Sand
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Source: Vein quartz/quartzite
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Process: Crushing → Color sorting → Screening → Magnetic separation
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Specs:
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Coarse sand (320–2500 mesh) for filler
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Fine sand (5–100 mesh, SiO₂ ≥98%) for aggregates
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B. Glass-Grade Sand
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SiO₂ ≥99–99.5% | Fe₂O₃ ≤0.015%
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Sorting: Washing → Scrubbing → Magnetic separation → Acid leaching
C. PV-Grade High-Purity Sand
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Source: Grade I/II natural quartz
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Price: Inner-layer sand: ¥190K–220K/ton | Imported: ¥600K/ton
D. Foundry Sand
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Types: Washed, scrubbed, dried, resin-coated
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Specs: SiO₂ 97.5–99.6% | Moisture <6%
E. Other Specialty Sands
| Type | SiO₂ | Fe₂O₃ | Grain Size | Uses |
|---|---|---|---|---|
| Refractory | ≥97.5% | 0.1–0.4% | 5.1–0.021mm | Furnace linings |
| Ceramic | >90% | 0.02–0.06% | 1–0.005mm | Glazes, bodies |
| Abrasive | >98% | <0.18% | 0.8–1.5mm | Grinding wheels |
| Blasting | >99.6% | <0.02% | 50–70 mesh | Rust removal |
Sorting & Purification Technologies
1. Scrubbing
Removes surface iron films and clay via mechanical friction.
2. Magnetic Separation
Eliminates magnetic impurities (hematite, biotite).
3. Flotation
Separates feldspar/mica from quartz.
4. Acid Leaching (HF/HCl)
Boosts SiO₂ purity to >99.99% by dissolving residual metals.
5. Photoelectric Sorting
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Technology: AI + visual imaging for pre-sorting lump ore.
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Supplier Example: Mind Photoelectric’s intelligent sorters for glass/PV/foundry sand.
Role of Square Swing Screeners in Silica Processing
For high-precision size classification, square swing screeners deliver:
✔ Uniform particle distribution (critical for PV/ceramic grades)
✔ Dust-free operation (meets HPQS standards)
✔ Energy efficiency vs. rotary/vibratory screens