Abstract: Provided is a gas-solid fluidized bed dry beneficiation process using a beneficiation density gradient, including: in a dry beneficiation system of a gas-solid fluidized bed, selecting coarse particles and fine particles; placing the coarse particles at a bottom of the dry beneficiation system, and placing the fine particles above the coarse particles, wherein the coarse particles and the fine particles are separated under an initial condition; under an effect of a gas flow, the coarse particles and the fine particles being fluidized to form a high-density beneficiation region and a low-density beneficiation region, respectively, and the coarse particles and the fine particles being mixed at a contact interface to form an intermediate-density beneficiation region; and feeding minerals to be beneficiated from an upper portion of the dry beneficiation system to pass through the low-density beneficiation region, the intermediate-density beneficiation region, and the high-density beneficiation region in sequence.

Abstract: Provided is a gas-solid fluidized bed dry beneficiation process using a beneficiation density gradient, including: in a dry beneficiation system of a gas-solid fluidized bed, selecting coarse particles and fine particles; placing the coarse particles at a bottom of the dry beneficiation system, and placing the fine particles above the coarse particles, wherein the coarse particles and the fine particles are separated under an initial condition; under an effect of a gas flow, the coarse particles and the fine particles being fluidized to form a high-density beneficiation region and a low-density beneficiation region, respectively, and the coarse particles and the fine particles being mixed at a contact interface to form an intermediate-density beneficiation region; and feeding minerals to be beneficiated from an upper portion of the dry beneficiation system to pass through the low-density beneficiation region, the intermediate-density beneficiation region, and the high-density beneficiation region in sequence.

Abstract: A corona charge spray gun for dispensing powders for powder coatings. The spray gun includes a housing defining a chamber terminating in an outlet passageway. A high voltage electrode is mounted in the chamber spaced upstream of the outlet passageway and a ground electrode is mounted in the chamber spaced upstream from the high voltage electrode. The ground electrode is selected to have a surface area sufficiently larger than the surface area of the high voltage electrode in order to allow high voltages to be applied to the high voltage electrode without arch discharging occurring in the chamber. An inlet opens into the chamber for conducting a powder-gas mixture into the chamber and the electrodes receive cleaning gases for avoiding powder deposits on the electrodes.

Abstract: A corona charge spray gun for dispensing powders for powder coatings. The spray gun includes a housing defining a chamber terminating in an outlet passageway. A high voltage electrode is mounted in the chamber spaced upstream of the outlet passageway and a ground electrode is mounted in the chamber spaced upstream from the high voltage electrode. The ground electrode is selected to have a surface area sufficiently larger than the surface area of the high voltage electrode in order to allow high voltages to be applied to the high voltage electrode without arch discharging occurring in the chamber. An inlet opens into the chamber for conducting a powder-gas mixture into the chamber and the electrodes receive cleaning gases for avoiding powder deposits on the electrodes.

Abstract: The present invention provides powder fluidization additives for increasing flowability of fine powders. The powder fluidization additives have both a smaller size than the fine powder and a mean apparent particle density less than the mean apparent particle density of the fine powder. The particles of the additive act to separate the fine powder particles and reduce interparticle forces allowing the flowability of the fine powder to be increased.

Abstract: The present invention provides a fluidized bed for dispensing small quantities of powders. The fluidized bed is made using a porous housing to permit injection and removal of fluid through the surrounding walls to improve the operation of the bed particularly for small particles of the group C size, including significantly reducing powder adhesion to the walls. In one aspect of the invention the fluidized bed housing is rotated about its longitudinal axis, which may be oriented at any suitable angle. A system for changing the volume of the bed is described as is a system for incorporating injection nozzles within the bed for constant agitation and prevention of powder adhering to the walls of the housing.

Abstract: The present invention provides powder fluidization additives for increasing flowability of fine powders. The powder fluidization additives have both a smaller size than the fine powder and a mean apparent particle density less than the mean apparent particle density of the fine powder. The particles of the additive act to separate the fine powder particles and reduce interparticle forces allowing the flowability of the fine powder to be increased.

Abstract: The present invention provides a fluidized bed for dispensing small quantities of powders. The fluidized bed is made using a porous housing to permit injection and removal of fluid through the surrounding walls to improve the operation of the bed particularly for small particles of the group C size, including significantly reducing powder adhesion to the walls. In one aspect of the invention the fluidized bed housing is rotated about its longitudinal axis, which may be oriented at any suitable angle. A system for changing the volume of the bed is described as is a system for incorporating injection nozzles within the bed for constant agitation and prevention of powder adhering to the walls of the housing.