FINE-DISPERSED CHALK PRODUCTION METHOD Russian patent published in 1996 - IPC

FIELD: chemical, rubber, electrotechnical, medicine industries and other, in particular heat pipelines insulation chalk production process, paints, polyvinyl chloride pieces and cable insulation production. SUBSTANCE: open pit produced chalk with humidity of 20 -30 % is used to prepare slime, that has 60 % water and 40 % chalk, that is averaged and elutriated. Then it is fed by hydraulic transport into rotational pulsation apparatus, in which chalk pulp particles are comminuted. After rotational pulsation apparatus, pulp is fed in vacuum-filter. Produced chalk cake with humidity of no less than 25 % is directed for drying in HF field with tension of 1000 - 1500 V/cm, formed by oscillator of meter wavelength range. Material after drying humidity is 0.5 %. Then material is fed in jet mill, in which under action of cold air pressure of 0.6 MPa chalk lumps are crushed to average size of 1.6 mcm. In the case fineness of milling is 10460 cm²/g . Granulometric composition: fraction of 7 - 13 mcm size - 30 %, fraction of 1 - 3 mcm size - 70 %. EFFECT: method allows to expand area of ready product usage due to increase of comminution fineness and uniformity of granulometric composition. 1 tbl