Ejector jet mill with external pressure

Jet mills are used to produce fine products in many industries. Spiral jet mills and fluidized bed jet mills are widely used. They differ in that the destruction of particles occurs as a result of the abrasion process. The use of impact ejector jet mills is limited by a relatively low consumable concentration of material. When the consumable concentration of the material increases the acceleration speed of particles and the material grinding degree decrease. To eliminate this disadvantage a new method and design of an ejector jet mill for fine grinding of bulk materials has been developed (patent of Russian Federation No. 2711252). The technological process occurs at excessive external pressure of the ejected gas. It is shown that it is feasible to increase the pressure at the beginning of the acceleration tube when the pressures ratio of the working and secondary gas is higher than the critical one. It increases the consumption concentration of bulk material and the acceleration speed of crushed particles. This allows reducing the specific energy consumption and increasing the grinding degree. Experimental studies have confirmed an increase in the consumption concentration by 1.6–1.9 times and an increase in the grinding degree by 1.3–1.7 times compared to a typical ejector jet mill.