METHOD OF POWDER JET GRINDING IN SUPERSONIC GAS MEDIUM AND DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2024 - IPC B02C19/06 

FIELD: crushing or grinding of various materials.

SUBSTANCE: invention relates to jet grinding of powders with subsequent classification of crushed material due to implementation of processes of interaction of material with gas jet in flow of hydrocarbon fuel combustion products and can be used in various industries in production of powders for various purposes, including ultrafine powders. As a result, microparticles with sharp edges are obtained, which causes a strong increase in their specific surface area. Bulk density of such powders is also considerably reduced. Sizes of finished product particles are controlled in a wide range, besides, they have single-mode, narrow granulometric fractions, in contrast to grinding made in ball, planetary, vibration and similar mills. Small dimensions of jet mills save production space, allow using expensive high-quality materials with long service life for making grinding chambers and their lining. Intensive formation of a branched activated surface of the particles takes place in the process of grinding. And also in case of dissimilar powders grinding high degree of mixture homogeneity is achieved. These conditions are optimal for chemical modification. In the supersonic thermal shock mill STM based on the present invention, a number of examples of many effective grinding modes are realized, namely: 1. classical dry (cold) jet grinding in air; 2. "hot" grinding; 3. milling using a supersonic oxygen-free jet of hydrocarbon fuel combustion products with controlled temperature in grinding zones, organization of grinding in STM with very low oxygen content, wherein hydrocarbon fuel combustion products are a reducing medium; 4. thermal shock (cyclic pulsating) grinding by creation of thermal shock on the surface of the ground material due to abrupt change of surface temperature up to hundreds of degrees per second. Thermal shock is significantly intensified with cyclic addition of dry ice granules to the supersonic flow and a supersonic jet pulsing with a certain frequency; 5. grinding in liquid phase with implementation of Rehbinder effect; 6. arrangement of waterlogged materials grinding with accelerated process of moisture removal from ground material; 7. arrangement of STM operation in the mode of thermochemical and mechanochemical reactors, using powders and liquids of different chemical composition and chemical activity. Proposed method and device for its implementation provide increase in the specific surface area of powder particles, decrease in the bulk density of the powders, increase in the degree of homogenisation of the mixture, and optimization of conditions for chemical modification.

EFFECT: increased specific surface area of powder particles, reduced bulk density of powders, increased degree of mixture homogenisation, optimization of conditions for chemical modification; many materials partially retain their microstructure, for example, the layered structure retains in graphite, mica, molybdenum sulphide; thus, the present invention leads to obtaining materials with new physical properties.

8 cl, 2 dwg