ANS:C - impact wheels

Mixing of light fine powders such as insecticides is typically done using a kneader. Here’s why:

1. Kneader:
   • A kneader, also known as a sigma mixer, is a type of batch mixer commonly used for mixing stiff pastes and dough-like materials.
   • It consists of two sigma-shaped blades that rotate within a mixing chamber.
   • Kneaders are particularly effective for mixing cohesive powders and sticky materials that tend to clump together.
   • The design allows for thorough mixing and kneading action, ensuring uniform distribution of additives or ingredients throughout the mixture.
2. Suitability for Fine Powders:
   • Light, fine powders such as insecticides require gentle handling during mixing to prevent agglomeration or degradation of the active ingredients.
   • Kneaders provide controlled mixing with low shear, making them suitable for blending fragile particles without causing excessive particle size reduction or damage.
3. Other Equipment Mentioned:
   • Banbury Mixer: Primarily used for rubber and plastics compounding, it involves intensive shearing and mixing, which may not be suitable for delicate powders like insecticides.
   • Pug Mill: Typically used for mixing and extruding ceramics, clay, and other materials, it may not provide the gentle mixing required for fine powders.
   • Impact Wheels: These are used for size reduction and grinding rather than gentle mixing, making them unsuitable for handling light, fine powders without degradation.