93results about How to "Control particle size distribution" patented technology

A circumferential seam type supersonic nozzle for metal gas atomization comprises a gas inlet pipe (4) connected with an external gas bottle. The gas inlet pipe is connected with an annular gas chamber (1) of the nozzle, the center of the nozzle is provided with a central hole (2), a supersonic gas spray pipe (3) of a circumferential seam structure is formed on the inner chamber wall and the outer chamber wall below the gas chamber and comprises stabilizing sections, contracting sections, throats and diffusion sections, a seam profile consists of symmetric curves, the profile of the whole spray pipe is the seam profile formed by the curves AB, BC and CD to take the axis of central hole (2) as the symmetry axis, the profile rotates by 360 degrees around the axis of the central hole (2) so that a curved surface is obtained, and an included angle alpha ranging from 0 degree to 6 degrees but not equal to 0 degree is formed by an extension line of a central line of each seam passage and the axis of the central hole of the nozzle in the profile of the gas spray pipe (3) passing through the axis of the central hole of the nozzle. The supersonic nozzle for gas atomization has the advantages that gas flow is uniform, turbulence level is low, and shock waves are absent in a flow field.

The invention discloses a preparation method of calcined kaolin with a low abrasion value. Coal-series kaolin rock or kaolin is screened, washed, smashed, ground, wet-ground and dried to obtain raw materials, the raw materials are depolymerized, scattered and calcined to generate mature materials, and finally the mature materials are depolymerized and scattered to generate finished products. The coal-series kaolin rock or kaolin is coal-permian concomitant coal-series kaolin rock or kaolin, and molar ratio of silicon to aluminum is SiO2 / Al2O3=1.9-2.1. Solid content of wet grinding mud is 42-50%, mud particle size (-2mu,%)>=93%, D50=0.3-0.8mu m. The particle size of the depolymerized and scattered raw materials is (-2mu,%)>=91.5%, D50=0.4-0.9mu m. By matching raw ore scientifically, optimizing raw material wet grinding process and controlling raw material scattering particle size distribution, a raw material abrasion value is controlled effectively, and the calcined kaolin with a low Einlehner abrasion value is obtained. Drug is not required in a preparation process, operation is convenient, cost is low, performance of product whiteness and covering power and the like can not be affected, and obtained products are easy to diffuse in a solution.

The invention relates to a battery-grade cobaltosic oxide preparation method, which comprises the following steps of: preparing solution of cobalt and solution of precipitator from a cobalt raw material and a precipitator by using de-ionized water respectively; preparing a precursor by using a homogeneous crystallization precipitation method, wherein the precipitate precursor is synthesized by adding the prepared solution of cobalt at a certain concentration and the solution of precipitator at a certain concentration into a reactor according to a certain molar ratio by using a cocurrent-flow feeding method, and effectively controlling chemical impurities, crystallinity of crystals, granularity, density and the like of the precursor by controlling parameters such as reaction temperature, feeding speed, PH value and stirring speed; directly filling a water-containing filter cake into a pot after washing and dewatering, and controlling grain size and crystal shape by using low-temperature dehydration phase-change calcination and high-temperature nodulizing sintering; crushing by using a machine and performing classified activation treatment; and finally, removing magnetic metal foreign bodies to obtain the battery-grade cobaltosic oxide similar to spheres. The battery-grade cobaltosic oxide has high density and high chemical purity, the grain size is easy to control, grain composition is uniform and narrow in distribution, and the magnetic metal foreign body content is low.