Chlorate Of Potash

Chlorate of potash (KOCIO5) is an anhy-drous salt, which crystallizes in the form of small spangles. They are larger when the crystallization is effected slowly. It is much more soluble in hot than in cold water.

Alcohol does not appreciably dissolve it. Chlorate of potash fuses at 750°; at a higher temperature it parts with its oxygen, and is ultimately reduced to chloride of potassium. On ignited coals it deflagrates vividly. It is one of the most active oxidizing agents, and forms explosive mixtures with the majority of combustible substances. Thus, an intimate mixture of it with sulphur, produces a violent detonation when placed on an anvil, and struck with a hammer. Those mixtures should be made with great care, and in small quantities to avoid accidents.

The detonating mixtures, formed of chlorate of potash, are much more powerful than the corresponding mixtures made with nitre. Gunpowder, much superior to that in ordinary use, has been made with chlorate of potash, but it was excessively explosive, and burst the fire-arms in which it was used. Its preparation and preservation being very dangerous, its manufacture has been abandoned.

A mixture of chlorate of potash and sulphur has also been used in the fabrication of percussion caps for guns, but fulminating mercury is now preferred.

If a drop of concentrated sulphuric acid be thrown on a mixture of sulphur and chlorate of potash, the sulphur takes fire. Advantage was taken of that property for producing fire, and the process was generally followed until it was superseded by the phosphoric matches.

Commercial chlorate of potash is sufficiently pure; but, before using it, the manufacturer must dry it completely.