Comprehensive Guide to Crushing and Sand-Making Production Lines in the Aggregates Industry
The global construction boom drives relentless demand for high-quality aggregates, including crushed stone, sand, and gravel. As urbanization accelerates, the crushing and sand-making sector has become pivotal in supplying raw materials for infrastructure, concrete, and asphalt. Modern production lines prioritize efficiency, environmental compliance, and product gradation to meet stringent industry standards.
1. Primary Crushing:
– Jaw Crushers: Ideal for hard rock (granite, basalt), reducing large blocks to 150–300 mm.
– Gyratory Crushers: Suited for high-capacity primary crushing in mining applications.
2. Secondary/Tertiary Crushing:
– Cone Crushers: Produce finely shaped aggregates (20–50 mm) with low flakiness.
– Impact Crushers: Versatile for softer limestone or recycled concrete, yielding cubical particles.
3. Sand-Making Stage:
– Vertical Shaft Impactors (VSI): Key for manufactured sand (0–5 mm), enhancing particle roundness and gradation.
– Sand Washers: Remove impurities (clay, dust) to meet ASTM/C33 standards.
4. Screening & Classification:
– Vibrating screens segregate aggregates into precise fractions (e.g., 0–5mm, 5–10mm). Multi-deck screens optimize productivity.
For mineral processing like kaolin, screening ensures purity before crushing:
1. Raw Material Pre-Screening: Removes oversized debris via bar screens or trommels.
2. Crushed Kaolin Screening: Fine-mesh screens (0.1–0.5 mm) separate kaolin from silica impurities post-crushing.
3. Dewatering Screens: Reduce moisture content for downstream drying/packaging.
Q1: How to minimize dust in crushing plants?
A: Enclose transfer points, install bag filters/spray systems, and opt for wet crushing where feasible.
Q2: What’s the ideal VSI rotor speed for granite sand?
A: 50–70 m/s tip speed balances particle shape (~15% <75µm) without excessive wear.
Q3: Can limestone and granite be processed in the same line?
A: Yes, but adjust crusher settings (e.g., CSS) and screen meshes to accommodate hardness differences.
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