A mining operation located in the mountains of Chile required an equipment method to handle and convey ammonium nitrate (NH4NO3) without degradation, 50 feet vertically, into a silo. Their current method of air conveying was damaging the prill of the material, resulting in an oxidizing agent which was proving less than expected reaction performance.
The solution was installing a Hapman tubular drag conveyor. This enclosed system is designed to handle a wide range of flowable materials and provides a high degree of protection, isolation and cleanliness. Degradation is limited due to gentle handling of the product in the tube and the use of a special Hapman chain which helps prevent wear and abrasion of the material being conveyed. This 6-inch diameter conveyor was constructed from a schedule 40 pipe for durability. A specially designed sprocket, with hardened teeth, drives the internal chain. The chain is connected to a heavy-duty gear reducer which is in turn driven by an energy-efficient 2 HP motor.
The prill degradation was eliminated, reaction performance when used as the oxidizing agent in detonations was excellent.