Hydraulic classifiers are provided for sorting material using injected water. Some embodiments include upper and lower housings having different cross-sectional shapes. In some embodiments, certain improvements are provided for cleanout and/or removal or replacement of teeter bars.

An apparatus for a spiral separator, for provision operatively intermediate upstream and downstream spiral trough parts of the spiral separator, including a slurry receiving region for receiving a mineral slurry flow from said upstream spiral trough part of the spiral separator; a splitter for splitting the mineral slurry flow into a concentrate part, a semi-concentrate part and a remainder part; a mixing region for mixing a more fluid radially more outward part of the remainder part with a less fluid radially more inward part of the remainder part, to provide a mixed remainder part for feeding onto the downstream spiral trough part; and a semi-concentrate bypass channel for conveying the semi-concentrate part towards the downstream spiral trough part, such that the semi-concentrate component bypasses and is segregated from the mixing region.

Described is a process for the refinement of a quartz powder, comprising the step of separating microparticles of refractory minerals, in particular minerals containing rare earth metal compounds, from the quartz powder by an elutriation step.

A method of separating a plurality of particles (14) from a portion of fluid, comprising directing the plurality of particles (14) into a microchannel (12). A first portion (16) of particles (14) is focused into an equilibrium position in the microchannel (12). The focused first portion (16) is directed into a first outlet (18) aligned with the equilibrium position. A portion of the fluid is directed into one or more outlets (20, 22). A microfluidic device (10) for separating a plurality of particles (14) from a portion of fluid, comprising a microchannel (12) having a first aspect ratio and a length L, thereby focusing the particles (14) directed therein into an equilibrium position in the microchannel, wherein at least a first portion (16) of the particles (14) focuses at distance X from a beginning of the microchannel (12). A first outlet (18) disposed after distance X and aligned with the equilibrium position to receive at least the first portion (16) of the particles (14) after the first portion (16) focuses into an equilibrium position in the microchannel (12). At least a second outlet (20) for receiving a second portion of the particles (14) before the second portion focuses into an equilibrium position.

A method of separating a plurality of particles (14) from a portion of fluid, comprising directing the plurality of particles (14) into a microchannel (12). A first portion (16) of particles (14) is focused into an equilibrium position in the microchannel (12). The focused first portion (16) is directed into a first outlet (18) aligned with the equilibrium position. A portion of the fluid is directed into one or more outlets (20, 22). A microfluidic device (10) for separating a plurality of particles (14) from a portion of fluid, comprising a microchannel (12) having a first aspect ratio and a length L, thereby focusing the particles (14) directed therein into an equilibrium position in the microchannel, wherein at least a first portion (16) of the particles (14) focuses at distance X from a beginning of the microchannel (12). A first outlet (18) disposed after distance X and aligned with the equilibrium position to receive at least the first portion (16) of the particles (14) after the first portion (16) focuses into an equilibrium position in the microchannel (12). At least a second outlet (20) for receiving a second portion of the particles (14) before the second portion focuses into an equilibrium position.

Provided is a gravity separation device wherein occurrences of shelving, flashing, and the like inside the device can be suppressed, variations in the flow rate of underflow obtained by gravity separation can be minimized and underflow can be stably extracted. This gravity separation device, which separates overflow and underflow using differences in specific gravity from mixed material, is provided with a separation section that has a supply pipe for supplying a slurry of the mixed material at the top and separates that slurry into overflow and underflow, and a deposition section that is positioned below the separation section and wherein the underflow that has been separated by precipitation is deposited. An extraction pipe for extracting the underflow is connected to the deposition section, and a valve for extracting the underflow and a metering pump for quantitatively extracting the underflow are provided in the extraction pipe.

This invention relates to an inverted up-flow separator, its use in a method of recovering target mineral particles from tailings and a process for the recovery of target mineral particles from tailings using the inverted up-flow separator of the invention.

An apparatus for processing aggregate material includes a chassis, a trough mounted on the chassis at an inclined angle, and at least one shaft rotatably mounted within the trough and extending from a lower to an upper end of the trough. The at least one shaft has blades mounted thereon, the blades being angled so that they carry material within the trough towards the upper end of the trough when the at least one shaft is in a normal direction of rotation. A discharge opening is formed in a base of the trough adjacent the upper end of the trough, a weir being provided in the trough upstream of the discharge opening over which processed material must pass to reach the discharge opening.

A method for producing a low iron silica sand product suitable for glass production has an SiO.sub.2 content of at least 99.8% by weight, an Fe.sub.2O.sub.3 content of less than 0.008% by weight, an Al.sub.2O.sub.3 content of less than 0.1% by weight, and a CaO content of less than 0.05% by weight includes preparing a slurry of crude ore, wherein the crude ore has a sand content of about 75% to 80% by weight, a kaolin/mica content of about 15% to 25% by weight, a dark, heavy mineral content of about 1% by weight, and an Fe.sub.2O.sub.3 content of about 0.5% to 1.0% by weight. Particles having a size of less than about one hundred forty mesh are removed, and contaminant material is removed. The sand is then separated from the slurry, dried, and passed through a rare earth magnetic separator.

A method for producing a low iron silica sand product suitable for glass production has an SiO.sub.2 content of at least 99.8% by weight, an Fe.sub.2O.sub.3 content of less than 0.008% by weight, an Al.sub.2O.sub.3 content of less than 0.1% by weight, and a CaO content of less than 0.05% by weight includes preparing a slurry of crude ore, wherein the crude ore has a sand content of about 75% to 80% by weight, a kaolin/mica content of about 15% to 25% by weight, a dark, heavy mineral content of about 1% by weight, and an Fe.sub.2O.sub.3 content of about 0.5% to 1.0% by weight. Particles having a size of less than about one hundred forty mesh are removed, and contaminant material is removed. The sand is then separated from the slurry, dried, and passed through a rare earth magnetic separator.