GROUPNEWS
Industrial Production of High-Quality Quartz Sand: A Comprehensive Guide to Crushing, Grinding, and Grading Processes
1. Raw Material Preparation
Quartz stone, primarily composed of SiO₂ (>99% purity), undergoes rigorous preprocessing to ensure optimal processing efficiency. Key steps include:
Impurity Removal: Initial screening removes visible contaminants (e.g., clay, organic matter) using vibrating screens and air classifiers.
Size Reduction: Large quartz blocks are pre-crushed into 20–50 mm fragments using jaw crusher, facilitating subsequent grinding.
2. Core Processing Stages
2.1 Crushing: Achieving Monomer Dissociation
The primary goal is to liberate quartz from associated minerals (e.g., feldspar, mica) and expose embedded impurities.
Jaw Crushers & Cone Crushers: Reduce raw quartz to 5–20 mm particles, ensuring uniform feed for grinding.
Impact Crushing: Secondary crushing refines particles to 1–5 mm, enhancing impurity exposure efficiency.
Critical Parameter: Target particle size of −0.425 +0.074 mm (−40 to +200 mesh), achieving ~52% qualified yield.
2.2 Grinding: Precision Particle Size Control
Advanced grinding technologies ensure micron-level consistency while minimizing contamination.
Ball Mills: Wet grinding with alumina balls reduces particles to 0.1–0.5 mm, minimizing iron contamination.
Raymond Mills & Vertical Roller Mills: Dry grinding achieves 325–2500 mesh (5–45 μm) for specialized applications (e.g., semiconductor-grade sand).
2.3 Grading: Multi-Stage Sieving for Precision
Particle classification ensures compliance with industry standards (e.g., ISO 3262-14:2025).
Vibrating Screens: Separate coarse (>0.425 mm) and fine (<0.074 mm) particles via multi-layer nylon sieves.
Air Classifiers: Achieve ultra-fine grading (D50 <10 μm) for high-purity applications (e.g., optical glass).
Key Data:
Coarse particle yield: ~40% (reprocessed via rod milling)
Fine particle yield: ~8% (used in ceramics or recycled).
3. Post-Processing: Purification & Quality Enhancement
3.1 Ultrasonic Desliming
Removes surface-adhered impurities (e.g., Fe, Al oxides) using ultrasonic baths (40–60°C, pH 2–4).
Reduces Fe content by 50–70% within 20 minutes.
3.2 Magnetic Separation
High-Gradient Magnetic Separators (20,000 Gauss): Remove paramagnetic impurities (e.g., hematite, ilmenite).
3.3 Acid Leaching (Optional)
For semiconductor-grade quartz (6N purity), HF/HCl mixtures dissolve residual lattice-bound Al and Ti.
4. Automation & Quality Control
AI-Driven Particle Analysis: Real-time monitoring via SEM-EDS and XRF ensures SiO₂ purity >99.995%.
Automated Calibration Systems: Multi-head thickness calibrators (e.g., KINGSUN KSYD 1650) achieve ±0.02 mm precision.
5. Environmental & Economic Considerations
Waste Recycling: 90% of grinding slurry is recycled via membrane filtration.
Energy Optimization: Heat recovery from grinding reduces total energy consumption by 25–30%.
