Sifting apparatuses for stratifying raw material including a material feed-in device, a material support unit, a gas plenum, a discharge control mechanism, and a reservoir are described. The material support unit receives material from the material feed-in device and has a surface with a plurality of openings for a gaseous medium introduced from underneath the material support unit, thereby effecting loosening and stratification of the material into a layer of relatively heavier material, and a layer of relatively lighter material atop the relatively heavier material. The introduced gaseous medium originates in a pump, is collected in a pressurized reservoir, and is controlled by a metered valve prior to introduction to the material support unit.

Fine particulate material is separated from a mixture of coarse particulate material and fine particulate material by passing sweep gas through the chamber of a rotating tumbler drum that contains an introduced material that is a mixture of coarse particulate material and fine particulate material. In particular, polysilicon powder may be separated from granular polysilicon. Seals are present, at locations where gas-conveying parts of the apparatus move relative to one another, to block the escape of sweep gas to the atmosphere surrounding the apparatus. A downstream seal extends between a stationary exhaust duct and an exhaust tube that rotates with the tumbler drum. The seal is protected by a flow of clean flush gas that is delivered to a gap between the exhaust duct and the exhaust tube.

Fine particulate material is separated from a mixture of coarse particulate material and fine particulate material by passing sweep gas through the chamber of a rotating tumbler drum that contains an introduced material that is a mixture of coarse particulate material and fine particulate material. In particular, polysilicon powder may be separated from granular polysilicon. Seals are present, at locations where gas-conveying parts of the apparatus move relative to one another, to block the escape of sweep gas to the atmosphere surrounding the apparatus. A downstream seal extends between a stationary exhaust duct and an exhaust tube that rotates with the tumbler drum. The seal is protected by a flow of clean flush gas that is delivered to a gap between the exhaust duct and the exhaust tube.

Provided is a classifier capable of classifying smaller microparticles and obtaining a narrower particle size distribution. The classifier includes a classification rotor constituted of a cylindrical body having a plurality of classification blades in an outer circumference portion thereof and having also an opening portion that opens in one lateral face thereof along an axis of the cylindrical body, a device body that accommodates the classification rotor and holds the classification rotator rotatably about the axis and that introduces classification-target powder from the outside and feeds the powder to the outer circumference portion of the classification rotor, and a discharging portion for drawing the powder classified by the classification rotor and removing the power to the outside of the device body, wherein a rotational shaft portion extending from an open face of the constriction portion to the other lateral face of the classification rotor has a diameter that increases progressively toward the other lateral face.

Fiberboard or chipboard is made by first comminuting vegetable starting material in a first comminutor into a stream of loose plant particles with silicate particles. Then, in a first classifier silicate particles of a diameter of less than 50 m are separated from the plant particles of the stream. The plant particles remaining in the stream are then glue-coated, and the stream is pressed into fiberboard or chipboard.

Sifting apparatuses for stratifying raw material including a material feed-in device, a material support unit, a gas plenum, a discharge control mechanism, and a reservoir are described. The material support unit receives material from the material feed-in device and has a surface with a plurality of openings for a gaseous medium introduced from underneath the material support unit, thereby effecting loosening and stratification of the material into a layer of relatively heavier material, and a layer of relatively lighter material atop the relatively heavier material. The introduced gaseous medium originates in a pump, is collected in a pressurized reservoir, and is controlled by a metered valve prior to introduction to the material support unit.

A sifting apparatus for stratifying raw material includes a material feed-in device, a material support unit, a gas plenum, and a discharge control device. The material support unit receives material from the material feed-in device and has a surface having a plurality of openings for a gaseous medium introduced from underneath the material support unit, thereby effecting loosening and stratification of the material into a layer of relatively heavier material, and a layer of relatively lighter material atop the heavier material. The introduced gaseous medium originates in a pump, is collected in a pressurized reservoir and is controlled by a metered valve prior to introduction to the material support unit.

A rotating suction chamber apparatus for sorting a mixture of materials comprises a cylindrical drum with its upper end is at a higher elevation than its lower end. An upper housing connected to the upper end has a material intake for receiving the mixture of materials for introduction to the upper end. The mixture of materials includes a light fraction and a heavy fraction, and the upper housing has an outlet for the light fraction. A suction hood connected to the light fraction outlet includes a light separator shaft with a substantially vertical portion, and an air blower is adapted to create an airflow from the lower end, to the upper end, through the light fraction outlet and through the suction hood. A rotator rotates the drum about its longitudinal axis so that the heavy fraction is moved through the drum and falls out of the lower end.

A rotating suction chamber apparatus for sorting a mixture of materials comprises a cylindrical drum with its upper end is at a higher elevation than its lower end. An upper housing connected to the upper end has a material intake for receiving the mixture of materials for introduction to the upper end. The mixture of materials includes a light fraction and a heavy fraction, and the upper housing has an outlet for the light fraction. A suction hood connected to the light fraction outlet includes a light separator shaft with a substantially vertical portion, and an air blower is adapted to create an airflow from the lower end, to the upper end, through the light fraction outlet and through the suction hood. A rotator rotates the drum about its longitudinal axis so that the heavy fraction is moved through the drum and falls out of the lower end.

Both a hydraulic (wet) separation process and a dry separation process are used in combination to recover sand, bentonite clay and organics from foundry waste created during operation of a green sand foundry. These recovered ingredients are then recycled for reuse in making additional green sand molds.