Melting, potassium perchlorate

The heat peUet used for activation in these batteries is usually a mixture of a reactive metal such as iron or zirconium [7440-67-7] and an oxidant such as potassium perchlorate [7778-74-7]. An electrical or mechanical signal ignites a primer which then ignites the heat peUet which melts the electrolyte. Sufficient heat is given off by the high current to sustain the necessary temperature during the lifetime of the appHcation. Many millions of these batteries have been manufactured for military ordnance as they have been employed in rockets, bombs, missiles, etc. 

The iron/potassium perchlorate mixtures react violently with each other. The exothermicity of the reaction is sufficient to melt part of the iron. This reaction is used to weld metal parts. 

Potassium perchlorate is prepared from potassium chlorate. Potassium chlorate, on heating, melts first and then resohdifies to potassium perchlorate ... 

This reaction is quite vigorous, and becomes violent at temperatures above 500°C [2]. The actual decomposition mechanism may be more complex than equation 3.1 suggests. Intermediate formation of potassium perchlorate has been reported at temperatures just above the melting point, with the perchlorate then decomposing to yield potassium chloride and oxygen [5]. 

Because of its higher melting point and less-exothermic decomposition, potassium perchlorate produces mixtures that are less sensitive to heat, friction, and impact than those made withKClO] [2]. Potassium perchlorate can be used to produce colored flames (such as red when combined with strontium nitrate), noise (with aluminum, in "flash and sound" mixtures), and light (in photoflash mixtures with magnesium). 

Potassium perchlorate is a white, non-hygroscopic crystalline material with a melting point of 6101C, considerably higher than the 356°C melting point of KCIO 3 It undergoes decomposition at high temperature... 

This material is rarely used as the only oxidizer in a composition, but is commonly combined with potassium perchlorate in red flame mixtures. It is a white crystalline solid with a melting point of approximately 570°C. It is somewhat hygroscopic, so moisture should be avoided when using this material. 

Several metallic sulfide compounds have been used as fuels in pyrotechnic compositions. Antimony trisulfide, Sb 2S3, is a reasonably low-melting material (m.p. 548°C) with a heat of combustion of approximately 1 kcal/gram. It is easily ignited and can be used to aid in the ignition of more difficult fuels, serving as a "tinder" in the same way that elemental sulfur does. It has been used in the fireworks industry for white fire compositions and has been used in place of sulfur in "flash and sound" mixtures with potassium perchlorate and aluminum. 

The apparatus constant shall be determined as follows. First prepare the melting curves for pure tin, indium, potassium nitrate, and potassium perchlorate. Next using the value of heat of fusion found in the literature, determine the relationship between the temperature and the apparatus constant Calculate the apparatus constant at the extrapolated decomposition temperature, and, in the abovementioned equation, use the value so obtained. 

Example 4. When potassium chlorate, KClOg, is carefully heated (at a temperature just above its melting point, and lower than that at which oxygen is evolved rapidly in the absence of a catalyst), potassium perchlorate, KCIO, is formed, together with potassium chloride, KCl. 1 low much potassium chloride must be taken to produce 500 g of potassium perchlorate ... 

Uranyl Perchlorate, UOjlCIO lj.hHgO, is prepared by adding perchloric acid to a solution of potassium uranate, filtering off the precipitated potassium perchlorate, and evaporating the filtrate over phosphorus pentoxide. It forms yellow prismatic ciy stals, which melt at 90° C, and at 100° C. lose water, yielding the tetrahydrate, V0, C10,) AB. 0. 

Molecular weight 211 63f colourless tesseral crystals, specific gravity 2 986 which is 1. times larger than that of potassium nitrate, and 1.2 times larger than that of potassium perchlorate. Thus the large density is one of the remarkable nature of strontium nitrate. It melts at... 

Potassium perchlorate, KCIO4, is made by heating potassium chlorate just to its melting point ... 

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