The Trunnion Magnet System bolts directly to the ball mill discharge flange to provide continuous magnetic collection of the grinding ball fragments. A permanent magnetic circuit collects the grinding ball fragments and discharges them to a collection hopper.
Grinding ball fragments discharging from ball mills cause extreme wear to downstream processing equipment. These ball fragments, circulating in a milling circuit, will cause excessive wear to sumps, pumps, hydrocyclones and interconnecting piping. Grinding ball fragments contribute very little to the grinding process while consuming power.
The Trunnion Magnet system consists of the blind trommel, magnet sector, support structure and the discharge hopper. The blind trommel is a short extension that bolts directly to the discharge flange of the ball mill. The function of the blind trommel is to transport the mill discharge material through the magnetic field. The blind trommel is fabricated from stainless steel and has an abrasion resistant wear liner. The magnet sector is comprised of permanent magnets and has an approximate 200-degree arc. This magnetic arc is mounted on a steel support pedestal and is positioned around the blind trommel. The permanent magnets are enclosed in stainless steel canisters and incorporate a steel back-bar for support and projection of the magnetic field. The discharge hopper and support structure is positioned just inside the blind trommel to collect the grinding ball fragments. The hopper collects the grinding ball fragments as they rotate past the end of the magnetic sector at the top of the blind trommel.
Features & Benefits
The removal of grinding media from the ball mill discharge has resulted in several benefits in the milling circuit. Benefits reported from independent sources are:
- Extended the pump life and the hydrocyclone life of approximately 250 percent.
- An increase in mill throughput of a nominal 5 percent.
- A nominal 7 percent reduction in mill power consumption.
- More efficient grinding
Other features and benefits include:
- Permanent magnetic circuit designed to provide maximum performance.
- No energy consumption.
- Rugged construction ensures long service life.
- Minimum maintenance.
- Continuous “Operator Free” process.