| 摘要 |
<p>A heat producing agent comprises a mixture of a reducing agent, such as aluminium or ferro-silicon or mixtures thereof, an amount of oxidizing well below the amount needed to react with the reducing agent to oxidize it completely and above 5 per cent and up to 10 per cent by weight of fluoride selected from alkali metal fluorides and sodium and potassium cryolite to facilitate burning of the reducing agent and lowering of the temperature at which the reaction starts. The oxidizing agent may be selected from potassium, sodium, strontium and barium nitrates, iron oxide in the form of ore or pure synthesised material or by-product such as hammer or rolling mill scale, manganese dioxide or nickel oxide. 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. Specification 774,490 is referred to.</p> |
