GB1324770A - Method for the grinding of coarse materials - Google Patents

Abstract

1324770 Reducing cement; tube mills FRIED KRUPP GmbH 1 July 1971 [2 July 1970] 30960/71 Heading B2A In a method of grinding e.g. cement raw materials, the raw material is ground in a first mill 5, the ground product 5a being then fed to a separator/sifter 7, a proportion of the course output 8 of the separator/sifter 7 being fed to a second mill 11, and the remainder of the coarse output being returned to the the mill 5. Proportioning is effected at 9, 10 by optimize the finished product. As described, materials e.g. cement clinker and gypsum are fed from bunkers 1, 2 by weigh-belts 3, 4 to the mill 5. Proportioning is effected at 9, 10 by the use of a microphone 14 which controls the filling level of mill 11. A sample from the product line 16 is analyzed by an apparatus 18 and signals therefrom also control the device 10. The weight-belts 3, 4 are controlled in response to product output weight sensed at 20. In a second embodiment discharge material from the first mill 5 is fed directly to the second mill 11. A variable quantity of material may be fed from the first mill directly to the second mill by a flap valve arrangement Fig. 2 (not shown). In both embodiments a more easily grindable material, e.g. gypsum, may be fed directly to the pulverizer 11 from the appropriate storage hopper.