| 摘要 |
1,217,003. Porous aggregates. JOHN G. STEIN & CO. Ltd. 10 Feb., 1969 [16 Feb., 1968], No. 7794/68. Headings C1A and C1H. Hard, strong, porous aggregates are formed by sintering clay, shale, slate or like watercontaining material and containing solid combustible matter by igniting the bed by a flame and drawing air through the bed so that sintering occurs in a zone that moves vertically downwards through the bed, the flame being applied to the bed at least until the sintering zone is about 5 inches below the surface, the ratio of air to fuel in the burning zone being increased but not decreased during this time, the sintering being continued by drawing air through the bed, no part of the bed being shock-cooled by contact with cold air. The charge may also include a material which acts as a flux at the sintering temperature, and carbonaceous fuel. Preferably the sintering is carried out downwardly on a stationary grate, the surface of the bed being raised as quickly as possible to the sintering temperature by igniting the bed by means of a burner hood fired by gas or oil. Alternatively a moving grate may be used with a succession of hoods of different temperatures. The charge may consist of pellets formed by moistening and rolling in a drum mixer, up to ¢ inch diameter made of - # inch particles. Alternatively, a plastic mass, made up of - # inch particles and water is broken up into strips up to 1 inch across and ¢ inch thick, and has carbonaceous fuel coated on each side. The amount of carbonaceous material added should be sufficient for the endothermic requirements of the sintering process. 1 part of cement is mixed with 2 parts of - <SP>3</SP>/ 16 and 2 parts of - # + <SP>3</SP>/ 16 of the above aggregate. |
