In a calcium carbonate (CaCO₃) plant, grinding and crushing are essential processes that transform raw limestone or other calcium carbonate sources into fine powders used in various industries. Here’s a breakdown of each process:
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1. Crushing (Coarse Size Reduction)
– Purpose: To break down large chunks of raw limestone or marble into smaller, manageable pieces (typically 5–50 mm).
– Equipment Used:
– Jaw crushers (primary crushing)
– Impact crushers or hammer crushers (secondary crushing)
– Process:
– Large rocks are fed into the crusher and compressed/impacted until they reach a smaller size.
– Crushed material is then screened to separate fines and oversized particles.
2. Grinding (Fine Size Reduction)
– Purpose: To further reduce crushed calcium carbonate into fine or ultra-fine powders (ranging from coarse 100-mesh to ultrafine 2,500-mesh).
– Equipment Used:
– Ball mills (for coarse to medium grinding)
– Raymond mills (for fine powder)
– Ultrafine grinding mills (e.g., vertical roller mills, stirred media mills, or jet mills for submicron particles)
– Process:
– Crushed CaCO₃ is fed into grinding mills along with grinding media (balls, rollers, or air jets).
– The material is ground until the desired fineness is achieved.
lassifiers (air separators) may be used to ensure uniform particle size distribution.
Key Differences:
| Feature | Crushing | Grinding |
|————–|———-|———-|
| Input Size | Large rocks (>50 mm) | Smaller particles (<50 mm) |
| Output Size | Coarse (5–50 mm) | Fine powder (<0.1 mm to microns) |
| Energy Use | Lower energy per ton | Higher energy per ton |
| Applications | Pre-processing before grinding | Final product for paints, plastics, paper, etc. |
Why Both Processes Are Needed?
– Crushing prepares the raw material for efficient grinding.
– Grinding achieves the precise fineness required for industrial applications like:
– Paints & coatings
– Plastics & rubber
– Paper manufacturing
– Pharmaceuticals & food
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