ANS:C - Screw conveyor

The most suitable conveyor for transporting sticky materials is an apron conveyor.

Explanation:

• Apron Conveyor: Apron conveyors feature metal plates or pans attached to a chain that runs beneath them. They are ideal for handling sticky, wet, or abrasive materials because the material adheres to the pans rather than accumulating on the conveyor belt or screws. Apron conveyors are commonly used in industries such as mining, cement, and chemical processing where sticky materials need to be transported reliably.
• Belt Conveyor: Belt conveyors are versatile and widely used for transporting bulk materials, but they may not be suitable for sticky materials as these can adhere to the belt surface, causing operational issues and material spillage.
• Screw Conveyor: Screw conveyors use a rotating helical screw blade to move materials along a tube or trough. While effective for many materials, sticky materials can adhere to the screw and trough, potentially causing blockages or inefficiencies.
• Pneumatic Conveyor: Pneumatic conveyors use air pressure to transport materials through pipes or ducts. They are suitable for certain types of materials but may not be the best choice for very sticky materials due to potential adherence and flow issues.

Advantages of Apron Conveyors for Sticky Materials:

• Prevents Material Buildup: The design of apron conveyors with metal pans or plates prevents sticky materials from adhering to the conveyor surface, reducing maintenance and operational issues.
• Reliable Operation: Apron conveyors can handle large capacities and are robust enough to withstand the demands of transporting sticky or abrasive materials over long distances.