Yellow flame compositions

A yeUow-orange flame color is easily achieved by atomic emission from sodium. The anission intensity at 589 nanometers increases as the reaction temperature is raised there is no molecular emitting species here to decompose. Ionization of sodium atoms to sodium ions will occur at very high temperatures, however, so even here there is an upper limit of tanperature that must be avoided for maximum color quality. 

A purer canary yeUow can be achieved pyrotechnically by blending green and orange. Pyrotechnic compositions that contain a barium compound (for green emission) and a calcium or sodium compound for yellow/orange color, can achieve some beautiful color effects in the yeUow region. Trial and error is probably the best method to use in finding the perfect mix for a desired hue. 

TABLE 8.15 Yellow Flame Compositions Composition % by Weight 

It must be ranembered that a little bit of sodium goes a long way in affecting flame color, due to the fact that sodium is an atomic, rather than a molecule emitter. A molecular emitter must form in the flame via a reaction between two chemical species. An atomic emitter requires no such flame chemistry to vaporize the atomic material, and it is ready to emit its atomic spectrum immediately upon vaporization in the pyrotechnic flame. A low percentage of a sodium impurity in a chemical can cause that chemical to affect flame color efforts to a significant extent, so quality control of raw materials is important when the production of a pure color is the goal. 

A set of U.S. Navy flare compositions, containing magnesium metal, is given in Table 8.16, showing formulas for bright red, green, and yellow flares.  

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Yellow flames for lances may be derived from compositions based on sodium nitrate or sodium oxalate, together with magnesium as fuel and a binder such as linseed oil. 

Colorless gas pungent suffocating odor human odor perception 0.5 mg/m hquefies by compression at 9.8 atm at 25°C, or without compression at -33.35°C (at 1 atm) sohdifies at -77.7°C critical temperature and pressure, 133°C and 112.5 atm, respectively vapor density 0.59 (air l) density of liquid ammonia 0.677 g/mL at —34°C dielectric constant at —34°C is about 22 extremely soluble in water solution alkaline pKa 9.25 in dilute aqueous solution at 25°C the gas does not support ordinary combustion, but bums with a yellow flame when mixed in air at 16— 27% composition. 

Flame color depends on fuel composition. Gas often burns blue, but heavy fuel oil burns yellow. A yellow flame is caused by thermal cracking of the fuel. There is nothing wrong with a yellow flame it is the general shape of the flame which is important. If in doubt as to the right flame shape for a particular furnace, contact the burner manufacturer for details. 

Illuminating Gas is formed by the destructive distillation of coal. It is a mixture of many gases, and its composition varies with the coal employed. The constituents are divided into three classes, viz. illuminants, diluents, and impurities. The first class contains, among other gases, ethylene and acetylene. Marsh gas, hydrogen, and carbon monoxide, all of which burn with a feeble — non-yellow — flame, are the most common diluents. The common impurities are carbon dioxide, hydrogen sulphide, and ammonia some of these, however, are entirely removed from the purified gas. Illuminating gas prepared as above is often called coal gas. 

Pine charcoal burns in combination with ammonium perchlorate at F/O = 2 10 producing a yellow flame, but no sparks or fire dust. A mixture of pine charcoal, sulphur and potassium nitrate in the weight ratio 30 10 60 burns producing pretty. orange red fire dust. This characteristic is generally seen with other charcoals but pine charcoal produces the most pretty fire dust of all. On the other hand, the phenomenon shows that pine charcoal does not complete the reaction and produces less gas in black powder-type compositions. Therefore pine charcoal is used to produce fire dust and not to obtain force. 

As Lancaster wrote (Fireworks, Principles and Practice, p.35(l9 2)), there are very few ingredients which produce yellow flames without any storage problem. Ultramarine is, however, one of them and it is suitable for ammonium perchlorate based compositions especially when they contain magnesiura(s. p.219). An experiment showed that there was no degeneration when the composition was stored for two years without raoistureproof containers. Under the same condition NallOa, NazSO/, NaaCaO or cryolite etc. caused degeneration by moisture. The only defect of ultramarine is that the yellow of the flame is rather weak and when it is used for chlorate or perchlorate based compositions, it produces much ash. 

However, the effect of hydrocarbon type composition is greater with wick-fed yellow flame burners than with wick-fed blue flame burners. With the former, kerosenes that are mainly paraffinic burn well in lamps with a poor draft, whereas under the same conditions kerosenes containing high proportions of aromatics and naphthenes burn with a reddish or even smoky flame. 

Na-D lines appear in almost all cases because every inorganic substance in firework composition contains sodium compounds as an impurity. The Na-D lines disturb any flame colour except a yellow flame. It may be difficult to obtain perfectly Na-free ingredients, but we must endeavour to get materials with a minimum sodium content. 

Ammonium nitrate [6484-52-2] NH NO, formula wt 80.04, is the most commercially important ammonium compound both in terms of production volume and usage. It is the principal component of most industrial explosives and nonmilitary blasting compositions however, it is used primarily as a nitrogen fertilizer. Ammonium nitrate does not occur in nature because it is very soluble. It was first described in 1659 by the German scientist Glauber, who prepared it by reaction of ammonium carbonate and nitric acid. He called it nittium flammans because its yellow flame (from traces of sodium) was... 

The yellow flame is caused by thermal cracking of the fuel. Anyone who has fired a residual oil burner knows that a yellow burner flame can be normal, depending on the fuel composition. 

Whereas there is no universally accepted specification for marketed natural gas, standards addressed in the United States are Hsted in Table 6 (8). In addition to these specifications, the combustion behavior of natural gases is frequently characteri2ed by several parameters that aid in assessing the influence of compositional variations on the performance of a gas burner or burner configuration. The parameters of flash-back and blow-off limits help to define the operational limits of a burner with respect to flow rates. The yeUow-tip index helps to define the conditions under which components of the natural gas do not undergo complete combustion, and the characteristic blue flame of natural gas burners begins to show yellow at the flame tip. These... 

The data in Table 7. 7 show that potassium nitrate, with its highly endothermic heat of decomposition, produces significantly lower flame temperatures with shellac than the other three oxidizers. The yellow light intensity will be substantially less for the nitrate compositions. 

Many other dyestuffs may be used. Paranitraniline Yellow gives a canary yellow smoke, and Flaming Red B gives a crimson-colored smoke by comparison with which the smoke from Para-nitranilinc Red appears to be scarlet. None of the colored smoke compositions are adapted to indoor use. All the smokes are unpleasant and unwholesome. 

Copper-I-chloride forms a white crystalline powder, which is stable in dry air, but tends to turn yellow, green, blue, or brown on exposure to moisture, air, and light. Store dry in airtight amber glass bottles. The dry crystals have a melting point of 430 Celsius. The crystals are relatively insoluble in water, with partial decomposition, but are soluble in concentrated hydrochloric acid, and ammonia solutions. Copper-I-chloride can be used in pyrotechnic compositions, for imparting cool effects to the flames. Copper-I-chloride is a very useful catalyst for use in chemistiy. 

If a spiral of platinum wire is heated in a bottle of hydrogen sulphide gas, a yellow powder and an invisible gas are formed the powder burns with a pale blue flame, producing a choking vapor, and the invisible gas burns with a colorless, hot flame. What evidence do these facts present about the composition of hydrogen sulphide ... 

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