Asbestos

Asbestos

While asbestos has been found in several states of the Union, in Italy, South and Central America, China, Japan, Australia, South Africa, and elsewhere, these deposits of the mineral have proved either of no commercial value or else are so situated as to be inaccessible, as far as the practical working of them is concerned. The world’s supply comes principally from Canada and Russia. At present, owing to conditions in the latter country, about 90 per cent is supplied by the Canadian deposits. This, substance is one of the most marvelous of the mineral products of organic nature. Its name as applied by mineralogists, asbestos, in the Greek form, signifies unquenchable, inextinguishable, inconsumable. It has been described as a “mineralogical vegetable,” and three minerals are classified under its name, as follaws: 1—antophyllite, which is not used commercially; 2—amphibolc or horneblende asbestos. This includes various varieties, among which are actinolitc and Italian asbestos; 3—Serpentine asbestos, which has three fibrous forms, namely picrolite, soapstone or talc, and chrysotile. The latter is the variety found in the Canadian deposits. In appearance and mineralogical character these varieties are somewhat different, while in chemical composition they are similar, the amphibolc varieties being composed of silicate of lime, magnesia, and alumina, while serpentine is a hydrated silicate of magnesia. The following is about the average chemical composition of the Canadian chrysolite asbestos: Silica, 40 per cent; magnesia, 42 per cent; ferrous oxide, 3 per cent; alumina, t per cent; and water, it per cent. While asbestos is non-inflammable, it is a mistaken idea to suppose that it is an absolute fire preventative, as under certain circumstances, such a reliance might prove very deceptive and dangerous. For instance, the placing of a superheated article, such as a gas stove or plumber’s furnace, on a wooden table or other object, covered with an asbestos pad, with the idea that the pad will be an absolute protection will result disastrously. and, with neglect, a fire may result. The reason for this is that while the asbestos itself will not burn, it is an excellent conductor of heat and the result would eventually be the ignition of the wood through the process of charring. Asbestos is very useful, however, in many ways, notably in its use as fire curtains in theatres, and other public places of amusement.

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