摘要 |
<p>An improved method of milling a particulate material in a jet mill is described. The material is fed from a holding vessel (1) to be entrained by a gas, the holding vessel (1) having an ullage which is maintained at a pressure of at least 0.05 MPa but less than the pressure at which gas is introduced to the jet mill. The method is particularly usefully employed in an impact jet mill in which the entrained particles impinge upon a surface (12), are reflected into another jet (13) and passed into a cylindrical separation chamber (17). The method enables such an impact mill to be operated under more energy-efficient conditions. <IMAGE></p> |