Abstract: An elongate flexible fuse is provided, preferably by an extrusion process, which consists of an oxidizing agent and a fuel present in quantities which will permit a rate of burning of from 10 seconds/meter to 250 seconds/meter. The oxidizing agent is preferably in finely divided form contained in a combustible matrix of fuel or is admixed with finely divided fuel and both contained in a matrix of different material. The ratio of oxidizing agent to fuel is at least 1:1 by weight.

Abstract: A process for preparing a solution of high aluminum content from the combustion residue of a solid carbon-containing fuel having a carbon content of 2% or less by weight and an iron content calculated as Fe.sub.2 O.sub.3 of 4% or less by weight is described. The process consists of (a) pretreating said residue with nitric acid at a temperature lower than the next extraction stage which follows and removing the nitric acid solution from the residue and then (b) extracting said treated residue with nitric acid of strength about 30% to 65% by weight strength at about 100.degree. to 225.degree. C., the amount of nitric acid employed in said pretreatment step and in said extraction step being in excess of the cationic equivalent actually dissolved in each step.