mineral processing technology and mineral processing equipment

In mineral processing plant ,As particles get finer the resistance against removing water increases. Gravity dewatering can no longer be used. We have to use pressure. By creating a differential pressure Δp across a cake of solids, liquid can be removed by Compression “Dewatering by compression means replacing the liquid in a cake with particles” Through blow Dewatering by through-blow means replacing the water in a cake with air” For vacuum filters air-through blow is used For vertical plate pressure filters either compression or a combination of compression and air through-blow is used For Tube Presses either compression or a combination of compression and airpurge is used. The Tube Press also enables cake washing. Drum Vacuum Filters Vacuum filtration is the simplest form of “through blow” dewatering. A pressure differential created by a vacuum applied to the inside of the filter drum causes air to flow through the filter cake thereby displacing the contain...

Mechanical dewatering means mechanical removal of liquids from a slurry to obtain the solids in a suitable form and/or recovery of a valueable liquid for: • Further processing • Transportation • Agglomeration • Disposal • Recovery of valuable liquids Gravimetric Dewatering When the particles in a slurry are too coarse for the capillary forces to “trap” the water, the use of gravity is enough to remove the water and give at least transportable solids. Spiral Dewaterer Spiral dewaterer for coarse solids (not deslimed). • Feed 1% solids by w. • 10 – 1 000 m3/h (44-44 000 USGPM) • Remaining moisture approx. 30% h2O • Large sedimentation-pool • Oil scimmer as option Sand spiral classifier (sand screw) This is a simpler version of the Spiral dewaterer mainly used for natural sand. These sands are normally classified (particles below 10-50 micron are removed) meaning that the sedimentation pool is very limited compared to the Spiral Dewater...

In mineralprocessing plant , With upgrading we understand, the further processing of the final products from the enrichment stages in a process. This is valid both concerning the valuable minerals (the concentrate) and the waste minerals (the tailings). In the first case upgrading means improving the product value by bringing the concentrate to transportability or into a completely dry form. Processing can also go further to calcining and sintering. On the tailing side upgrading means that waste material (wash water, process effluents etc.) is properly taken care of in order to protect the environment, to recover process water and to turn certain portions into valueables. Sedimentation Sedimentation is a continuous solid-liquid separation process with settling of solids by gravity. Clarification is the process for removal of solids from a dilute solid/liquid suspension. Thickening is the process for concentrating particles in a supension by gravity compression Flocculatio...

When mechanical methods of separation cannot secure optimal metal value of an ore,leaching is an alternative, either as a complement or as an overall process. Most of the leaching process is feed preparation by crushing, grinding and in some cases pre-concentration and roasting. The separation is normally done by creating retention time for the chemicals to penetrate the feed. The waste and heap leaching operations are typically low in investment but high in cost of chemicals. Recovery is normally low (below 60%). The agitation methods (con current or counter current) are high in investment but are paid back in higher recovery. Leaching by size In leaching there is always an optimum in the relation feed size versus recovery. This balance between cost for size reduction and value recovery is important to establish for high value ores, see below. Leachants Leaching of Metals Below find the flow sheets for classical leaching circuits, heap leaching for coarse...

In mineral processing plan t , By creating an environment comprimising a magnetic force (Fm), a gravitional force (Fg) and a drag force (Fd) magnetic particles can be separated from nonmagnetic particles by Magnetic Separation. Competing forces • Gravitational force (Fg) determined by particle size and particle density. • Hydraulic force (Fd) for wet magnetic separators, determined by particle diameter, shape, liquid viscosity and velocity (see wet LIMS and wet HGMS below.) • Centrifugal force (Fc) for rotating dry magnetic separators, determined by particle size, density and drum speed. (see dry LIMS below.) • Air drag force (Fa) for dry magnetic separators, determined by particle size, density and air velocity. (see dry HGMS below). Separator Types Wet LIMS = Low Intensity Magnetic Separator • Wet separation of ferromagnetic particles • Magnetic field in separation zone * = 1-3 kGauss * approx. 50 mm (2 inches) from drum surface Wet HGMS = High Gra...