GB774490A - Improvements in or relating to heat producing mixtures - Google Patents

Abstract

A heat producing agent comprises a mixture of reducing agents including carbon and aluminium, an amount of oxidizing agent well below the amount needed to oxidize the reducing agent completely and between 1 per cent and 10 per cent by weight of an alkali metal fluoride, sodium aluminium fluoride or potassium alumini fluoride to facilitate burning of the reducing agent and lowering of the temperature at which the reaction starts. The oxidizing agent may be potassium, sodium, strontium or barium nitrate, iron oxide in the form of ore, pure sythesized material or a by-product such as hammer or rolling mill scale, manganese dioxide or nickel oxide and the carbon may be used in the form of coke. An organic or inorganic bonding agent, e.g. gum arabic, and inert filler material such as sand may be added and the mixture formed as or embodied in a shaped article. An example contains graded aluminium powder 20 per cent, graded coke 30 per cent, cryolite 4 per cent, gum arabic 4 per cent, manganese dioxide 12 per cent, sodium nitrate 10 per cent, boric acid 1/2 per cent, tannic acid 1/4 per cent and sand 19 1/4 per cent. The Provisional Specification describes also mixtures in which the aluminium is wholly replaced by carbon or other reducing agents such as ferro-silicon. Specifications 627,678 and 774,491 are referred to.