High Capacity Disc Filters

The primary application for FLSmidth Minerals High Capacity Disc Filters is liquid/solid separation of Seed Hydrate in the precipitation circuit of the Bayer flowsheet. These large diameter Disc Filters are made of several parallel discs with a diameter of up to 6.0m, providing maximum filtration area with minimum cost and operating space. Each disc is rotating in its own narrow trough. There are no additional agitators required in the bottom of the troughs as circumferential disc rims are provided.

Operating Principle
Slurry is fed into the trough and kept in suspension by an efficient agitation effect of the disc paddles which maintain homogenous slurry providing uniform cake thickness, resulting in lower moisture and higher production. As the large diameter shaft rotates, the filter discs travel through the slurry. Vacuum is applied to the sectors as they enter the slurry and cake forms on the surface of the filter media. After the sector leaves the slurry, the continuous vacuum pulls air and filtrate through the inside of the sector into and along the trapezoidal channel of the main shaft and out through the large diameter valve to the vacuum receivers. Vacuum cut-off occurs just before the dewatered cake-laden sector approaches the discharge point. Pressurized air the loosens the cake from the filter media and guided deflector blades direct the cake as it falls through the wide discharge chutes for removal. The slurry level in each trough can be adjusted to allow for higher filtration capacity or lower cake moisture.