Colour of fire dust

As described in 8.2, the colour of fire dust depends upon the temperature and the kind of material. Aluminium can produce orange, yellow or gold, white-yellow, silver. Black powder-type compositions produce dark red to a kind of bright orange. These colours are adjusted practically by the selection of the types of oxidizers and fuels and the regulation of F/0 (s.l5). 

The colour of flames described earlier is very clear and gives us a somev/hat sharp feeling, but the colour of fire dust is gentle and elegant. 

The colour of fire dust 10.3 The division of fire dust particles... 

The fire dust or sparks which are produced by iron or carbon create the colour which resembles that of the black body. The colour of the sparks of Senko-Hanabiwhich is caused not only by carbon but also other materials, also resembles the colour of the black body. We feel that the. colour of the aluminium fire dust is a little different from the black body. The colour changes from red-orange to yellow, white yellow and silver as the temperature increases, and the locus may be written as the line... 

Fig.33) Anyhow we can produce various colours of the fire dust or sparks except blue and green by adjusting the temperature and selecting substances which make up the component material in firework compositions according to the principle of the colour temperature. 

It is thought that fireworks began with the history of potassium nitrate. It has. been used for compositions which produce fire dust or sparks as well as a white smoke which has been called "Wabi (Japanese fire). It could not produce coloured flames, but before the appearance of potassium chlorate, fireworkers made various efforts to create colour with it as far as possible. 

This is mentioned also in 7 2. This produces a pretty silver fire dust. When we change the weight ratio x/, the fire dust is obtained in various forms with slight changes of colour. If the proportion is 5O/50 there is a large silver fire dust flame of short duration where the proportion... 

The boric acid prevents the potassium nitrate and aluminium from reacting v ith each other(R.Lancaster Fireworks, p.31(1972)). No.l and No.2 produce a pretty golden fire dust. No.3 produces a somewhat reddish gold effect, and looks more elegant than Nol and No.2. When we use antimony trisulphide, sulphur and realgar, as components in one composition with various ratios between them, various colour tones of gold can be obtained. 

Ground-hog Kiln. US term for an art-potters kiln (usually fired with solid fuel) partly buried in a convenient hillside to support the roof and conserve heat. Ground Laying. A process for the application of a uniform coating of colour to pottery-ware by painting with oil the area to be coloured and then dusting powdered colour over the ware the colour sticks only where oil has been first applied. The process is now used only for the decoration of some expensive types of china and porcelain. Ground Mass. See matrix. 

A paste with mixture of the clay and saw dust (of about 20 micron size) with different proportions (depending on the plasticity of clay used) is given the needed shape and fired to make it hard porous solid ready for filtration. This very simple type filter can only filter out the particles and colour out of water but is unable to remove bacteria. 

This material occurs as vanadium ore but is also found in petroleum oil. It is also used to make alloy steels and as a catalyst in many chemical reactions. Exposure to the metal occurs when oil-fired boilers are cleaned and manifests itself in eye irritation, shortness of breath, chest pain and cough. The tongue becomes greenish-black in colour. Severe cases may develop broncho-pneumonia. Removal from contact with the dust usually leads to rapid recovery. 

---