Which of the following is not classified as an ultrafine grinder or colloid mill ?
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Answer: C. Toothed roll crusher
Explanation
Toothed roll crushers are designed for primary or secondary size reduction of soft rocks. They operate by compression and tearing rather than ultrafine grinding or colloid milling. Therefore, toothed roll crushers are not classified as ultrafine grinders. Ultrafine grinders produce sub-micron particles through intense impact, shear, and attrition. Fluid energy mills and micronizers achieve extreme size reduction using high speed gas jets. Colloid mills use high speed rotor stator designs to disperse fine particles in liquids.
Toothed roll crushers are commonly used for crushing coal, salt, and soft minerals. Ultrafine grinders are reserved for specialized pigments, pharmaceuticals, and ceramic powders. Mixing up primary crushers with ultrafine mills leads to catastrophic equipment failure. Micronizers are specialized ultrafine fluid energy grinders used for high purity powders. Agitated mills and fluid energy mills achieve extreme particle size reduction efficiently. Hammer mills with internal classification are capable of producing very fine ground products.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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