GB575053A - Improvements relating to the agglomeration of iron-bearing materials - Google Patents

Abstract

575,053. Rotary furnaces. SMIDTH & CO., Ltd., F. L. Feb. 23, 1944, No. 3409. Convention date, Feb. 8, 1943. [Class 51 (ii)] [Also in Group II] A method of converting finely divided ironbearing materials into the form of nodules suitable for treatment in furnaces in which an agglomerating-agent in the form of a mixture of ferric oxide and lime in such proportions that the mixture will pass directly from the solid to the liquid state on heating is caused, while molten, to coat the iron bearing materials and so agglomerate them into nodules. The agglomerating-agent may contain from 15-32 per cent. of lime. Preferably the amount of the agent used is from 10-25 per cent. of the weight of the iron bearing materials. In one method of carrying out the invention, a mixture of materials which will provide ferric oxide and lime is added to the iron-bearing materials and the resulting mixture is agitated and heated. This operation may be performed in a rotary kiln from which the nodulised material is discharged. Alternatively the agglomerating-agent may be separately prepared and added in a molten state to the iron-bearing materials. In the apparatus shown, the mixture of lime and ferric oxidebearing materials is fed by a hopper 14 to a rotary kiln 10 heated by a burner 16 projecting into a hood 15. In the kiln the material is calcined and melted and collects in molten form in the bottom of the hood 15. Iron-bearing materials are fed by a screw conveyor 27 to the rotary nodulising drum 22. This drum is heated by burner 23, into the blast from which the molten agglomerating-agent drops from a nozzle 20 and is sprayed over the iron-bearing materials. The mixture hardens rapidly in the form of nodules on leaving the hot zone. These fall into a hopper 21 and pass through a cooler 29 where they are cooled in an air blast, which provides pre-heated air for combustion at burners 23 and 16.