A process for the recovery of flue ash with a high concentration of metals or metallic compounds

摘要

527,863. Returning fuel residues to furnaces. NAAMLOOZE VENNOOTSCHAP DE BATAAFSCHE PETROLEUM MAATSCHAPPIJ. April 21, 1939, No. 12087. Convention date, May 14, 1938. [Class 51 (i)] [Also in Group II] Flue ash deposited from gases formed in the combustion of fuels containing metals or metal compounds, such as vanadium or vanadium compounds, is treated to obtain a product with a high concentration of metals or compounds by separating into coarser and finer portions; the values are concentrated in the finer portion, and the coarser portion is recirculated to a combustion space. Preferably 90-95 per cent. of the ash is separated as the coarser portion. The whole of the ash may be separated from the gases and then divided into coarser and finer portions, or preferably the coarser and finer portions are collected from the gases separately. The coarser ash may be ground before returning it for further combustion. Preferably, all the ash is separated at least once as coarse ash, and the fuel may be atomized or ground to such an extent that ash particles of a uniform size are obtained. Separation may be effected by cyclones, filters, or electric separators, or the coarse ash may be separated by means of an oil filter or coke bed, or the gases may be passed through a bunker to deposit the coarse ash directly on the fuel.