A filter press is a mechanical dewatering device widely used in mining and mineral processing to separate solids from liquid slurries by applying pressure across a series of filter plates and membranes. It is one of the most efficient and commonly used filtration technologies in bauxite, gold, iron ore, and diamond mining operations, capable of producing filter cakes with very low residual moisture content.
The fundamental operating principle of a filter press involves pumping the feed slurry under pressure into a series of recessed chambers formed between adjacent filter plates. Each plate is covered with a filter cloth or membrane through which the liquid phase (filtrate) passes while the solid particles are retained and build up as a filter cake within the chamber. As filtration progresses, the cake layer itself becomes the primary filtering medium, trapping progressively finer particles.
Filter presses are available in several configurations including plate-and-frame, recessed chamber, and membrane (diaphragm) designs. Membrane filter presses incorporate inflatable diaphragms that can squeeze the filter cake after the filtration cycle, achieving even lower moisture contents than conventional recessed plate designs. This makes membrane filter presses particularly valuable in iron ore pellet feed applications where moisture control is critical.
Plate sizes in mining applications can range from 800mm to 2,000mm or larger, with the number of plates determining the total filtration area and throughput capacity. Key performance parameters include cycle time, cake moisture content, filtrate clarity, plate washing efficiency, and cloth life. Automated cloth washing systems and hydraulic plate-shifting mechanisms are commonly incorporated to minimize manual labor and maximize throughput.