Filter Type Options

As discussed in the Dewatering of Tailings section, there are a number of filter types that can and are used in tailings dewatering. Click on the icons below to go to the relevant explanations pages, including specific information on test work to obtain useful parameters for scale-up of that filter type.

Filter Presses

Filtration machines that utilise high pressure (pumping of slurry into the filter) and produce filter cake in batches. Some very large tailings dewatering plants that use filter presses are operating currently.

Filter Presses incorporate a series of vertical plates arranged horizontally within a steel structure. Each plate is covered with a filter cloth, and when the plates are held together (usually by a hydraulic system) they form a set of sealed chambers, usually with cloth on each side. Slurry is pumped into these chambers, and water passes through the cloth while the solids are retained inside, forming a filter cake. This may be followed by a cake press (using rubber membranes) and/ or an air blow to remove water held within the cake. At a certain point (triggered by time or pressure), the system releases the plates, which then separate and filter cake drops out.

Disc Filters

Filtration machines that produce filter cake continuously, with a small plant footprint. Disc Filters incorporate a number of discs, each with a number of sectors, located on a rotating shaft. As the shaft rotates, each sector passes through a slurry trough and cake forms on its outer surface. After leaving the through, further dewatering occurs during the remainder of the rotation, until the filter cake is dislodged, passing through a chute. Disc filters can have cloth or ceramic media and operate under vacuum or pressure within a hyperbaric vessel.

Belt Filters

Filtration machines that utilise vacuum and produce filter cake continuously. Slurry is fed onto a moving porous belt, where water drains by a combination of gravity and vacuum to form a filter cake. At the end of the belt, the cake is discharged (often assisted by scrapers). Operators can easily see that process and make adjustments and these machines can be used for efficient filter cake washing.

Tower Presses

Filtration machines that operated in a similar way to filter presses. While they have a limited size, and therefore processing capacity, when compared to filter presses, these units may offer some compelling benefits for a smaller plant throughput.

Other methods

There are other methods of dewatering/ filtration equipment that have been used for tailings dewatering and water recovery from tailings. These include centrifugation, screw-presses & forms of in-situ drainage. These are not included in the calculator because i) they are less common, to date, than the forms above and ii) we have not yet implemented robust scale-up rules from simple tests for them.