摘要 |
The invention concerns a method for preparing a blend consisting of power station ashes and/or slugs, and/or coal wastes in a quantity of 60-95% by weight, as well as an agglomeration promoting binder, including sewage after-fermentation sludge in a quantity of 5-40% in the dry state, said blend being so prepared that its total moisture contents is below 21%, and while maintaining features of a pourable material it can be homogenized in mixers provided with high speed rotary homogenizing means. After agglomerating said blend is fired in a rotary furnace. A firing method is characterized by that the rotary furnace operates with charge and gas phase moving in the co-current arrangement, what enables almost autothermal process with firing in the same time harmful volatile substances released from a binder. Said autothermal process is also promoted by the double-diameter structure of the furnace (a wider part 1A and a narrow par 1B), by its substantial slope, precise insulated heads 2 and 7, as well as gas ducts 3 and 14, and by dividing thee air stream, one part of which is directly supplied through the layer of the material being fired and sintered. |