Fine coal is cleaned of its mineral matter impurities and dewatered by mixing the aqueous slurry containing both with a hydrophobic liquid, subjecting the mixture to a phase separation. The resulting hydrophobic liquid phase contains coal particles free of surface moisture and droplets of water stabilized by coal particles, while the aqueous phase contains the mineral matter. By separating the entrained water droplets from the coal particles mechanically, a clean coal product of substantially reduced mineral matter and moisture contents is obtained. The spent hydrophobic liquid is separated from the clean coal product and recycled. The process can also be used to separate one type of hydrophilic particles from another by selectively hydrophobizing one.

A minerals processing system (200, 300) comprising a flotation circuit (109) is characterized in that a dry grinding circuit precedes the flotation circuit (109). The dry grinding circuit may use a vertical roller mill (32) or roller grinder (302), and at least one dry air particle separation device (201, 304, 307) positioned between said vertical roller mill (32) or roller grinder (302) and the flotation circuit (109). The at least one dry air particle separation device (201, 304, 307) produces a dry fines stream (38) and a dry coarse stream (202). The coarse stream (202) is provided to the flotation circuit (109) to recover metal values, whereas the dry fines stream (38) circumvents the flotation circuit (109) and is combined with dewatered tailings (116) derived from material (110, 111) leaving the flotation circuit (109).

A minerals processing system (200, 300) comprising a flotation circuit (109) is characterized in that a dry grinding circuit precedes the flotation circuit (109). The dry grinding circuit may use a vertical roller mill (32) or roller grinder (302), and at least one dry air particle separation device (201, 304, 307) positioned between said vertical roller mill (32) or roller grinder (302) and the flotation circuit (109). The at least one dry air particle separation device (201, 304, 307) produces a dry fines stream (38) and a dry coarse stream (202). The coarse stream (202) is provided to the flotation circuit (109) to recover metal values, whereas the dry fines stream (38) circumvents the flotation circuit (109) and is combined with dewatered tailings (116) derived from material (110, 111) leaving the flotation circuit (109).

A method of improving grinding, grading and capacity of ores by reducing a fineness content ratio θ.sub.0 in settled ores includes providing a two-stage ore grinding and grading system including a first fully closed circuit including a grinder and a hydrocyclone, or a two-stage ore grinding and grading system including a first-stage open circuit, and controlling parameters for ore grinding and grading as follows: controlling a dc an value of a point B on a separation cone of a second-stage Φ500 mm hydrocyclone; controlling a fineness content ratio θ.sub.0 in settled ores; controlling a second-stage ore grinding and grading load Q.sub.2; and acquiring a first-stage grinding, grading and capacity Q of ores.

A method of improving grinding, grading and capacity of ores by reducing a fineness content ratio θ.sub.0 in settled ores includes providing a two-stage ore grinding and grading system including a first fully closed circuit including a grinder and a hydrocyclone, or a two-stage ore grinding and grading system including a first-stage open circuit, and controlling parameters for ore grinding and grading as follows: controlling a dc an value of a point B on a separation cone of a second-stage Φ500 mm hydrocyclone; controlling a fineness content ratio θ.sub.0 in settled ores; controlling a second-stage ore grinding and grading load Q.sub.2; and acquiring a first-stage grinding, grading and capacity Q of ores.

The present invention proposes a coal and gangue separation device, including a first supporting seat, a guide part and multiple material bins. The guide part is hinged with the first supporting seat; the guide part rotates in a vertical direction; and inlets of the plurality of material bins are sequentially distributed on a rotation track of a movable end of the guide part. In the coal and gangue separation device of the present invention, the high-pressure airflow of a high-pressure nozzle does not directly act on the materials, but on grate bar driving mechanisms; and cantilever grate bars are driven to rotate by the grate bar driving mechanisms so as to directionally discharge the mineral aggregate. Therefore, the gangue can accurately enter a gangue collection bin; and the clean coal can accurately enter a clean coal collection bin.

This invention relates to a process of comminution of iron ore or iron ore products (pellet feed, sinter feed, etc.) at natural moisture without the need to add water or to include a drying step in the process, that is technically and economically feasible. The comminution process of this invention uses at least one piece of equipment selected from the group consisting of roller press (HPGR), vertical roller mill (VRM), roller crusher (RC) and high acceleration screen of at least 10G.

An apparatus for washing and grading sand includes a first vibrating screen having a deck arranged to receive a feed material. Oversize material passes over the deck of the first vibrating screen for collection as a first product, and undersize material and water are collected in a sump of the first vibrating screen before being pumped to a hydrocyclone. A second vibrating screen receives an underflow from the hydrocyclone upon a deck thereof, with oversize material passing over the deck of the second vibrating screen for collection as a second product. An overflow from the hydrocyclone passes into a settling tank, and a water storage reservoir receives water overflowing from the settling tank while sludge is collected and removed from a lower end of the settling tank. Water is passed from the water storage reservoir to the first and second vibrating screens to wash and fluidise material thereon.

An apparatus for washing and grading sand includes a first vibrating screen having a deck arranged to receive a feed material. Oversize material passes over the deck of the first vibrating screen for collection as a first product, and undersize material and water are collected in a sump of the first vibrating screen before being pumped to a hydrocyclone. A second vibrating screen receives an underflow from the hydrocyclone upon a deck thereof, with oversize material passing over the deck of the second vibrating screen for collection as a second product. An overflow from the hydrocyclone passes into a settling tank, and a water storage reservoir receives water overflowing from the settling tank while sludge is collected and removed from a lower end of the settling tank. Water is passed from the water storage reservoir to the first and second vibrating screens to wash and fluidise material thereon.

A washing apparatus comprises a screening apparatus having a first screening deck located below a second screening deck, wherein the first screening deck passes material that is larger than the material passed by the second screening deck. A liquid delivery system delivers liquid onto the first screening deck to wash material on the first deck. Material that passes through the first deck is conveyed upwards and delivered onto the second deck for dewatering. The apparatus is able to wash and dewater aggregate material in a single unit with a relatively small footprint and relatively high throughput.