Strontium combustion

Fine powdered strontium combusts spontaneously in air. It reacts more violently with water than calcium and produces hydrogen and strontium hydroxide. 

Health and Safety Factors. The strontium ion has a low order of toxicity, and strontium compounds are remarkably free of toxic hazards. Chemically, strontium is similar to calcium, and strontium salts, like calcium salts, are not easily absorbed by the intestinal tract. Strontium carbonate has no commonly recognized hazardous properties. Strontium nitrate is regulated as an oxidizer that promotes rapid burning of combustible materials, and it should not be stored in areas of potential fire hazards. 

Molten lithium reacts violently with strontium and the mixture can combust. 

Lead peroxide is even more active than the oxide. It reacts violently with sulphur and sulphides. When it is ground up with sulphur, the mixture combusts. With hydrogen sulphide, the reaction is very exothermic and causes peroxide to incandesce and hydrogen sulphide to combust. Finally, it reacts violently with calcium, strontium and barium sulphides on heating. 

Marinho EP, Souza AG, de Melo DS, Santos IMG, Melo DMA, and da Silva WJ. Lanthanum chromites partially substituted by calcium strontium and barium synthesized by urea combustion—Thermogravimetric study. J. Thermal Analysis Calorimetry 2007 87 801-804. 

Deshpande K, Mukasyan A, and Varma A. Aqueous combustion synthesis of strontium-doped lanthanum chromite ceramics. J. Am. Ceram. Soc. 2003 86 1149-1154. 

During combustion, strontium nitrate and strontium carbonate decompose to give strontium oxide whose spectrum is seen as a pinkish flame due to the positions of the emission bands and to the difficulty in obtaining a high concentration of strontium oxide vapour in the flame. This difficulty is due to the high sublimation temperature of the oxide which is in excess of 2500 °C. 

Strontium peroxide is a strong oxidizer and can cause fire when in contact with combustible materials. It is a powerful irritant to skin, eyes, and mucous membranes,... 

C = Potassium chlorate base composition(6 /o potassium chlorate, lk% combustion agent, 13 strontium carbonate, G% binding agent). 

Fig.56 Content of glutinous rice starch and the characteristics of a chlorate composition(67 parts potassium chlorate, Ik parts BL combustion agent, 13 parts strontium carbonate and X parts starch by weight).

Pulverized barium or strontium nitrate consolidates into a hard mass over a period of time. These substances are dried above 100°C and stored in a moistureproof container,e.g. a steel drum. Nitrates are sometimes placed in a iron pan and heated over a direct heat with constant stirring. It is not dangerous unless a combustible material is added... 

These comprise, on the one hand, easily combustible substances such as charcoal, sulphur, antimony sulphide, resins, and tar and on the other hand, they include substances which readily give up oxygen and support combustion, such as saltpetre (potassium nitrate), and potassium chlorate or other chlorates. A third category includes those substances used for the various colour effects (barium strontium, copper, and other salts), and also finely divided metals, and coarse particles of charcoal to cause sparks and showers of fire ( golden rain and the like). Other substances are sometimes used to decrease the rate of burning and to increase brilliance (r.g. mercurous chloride and mercuric thiocyanate). 

Potassium chlorate base compos it ion(67% potassium chlorate, 14% combustion agent, 13% strontium carbonate, 6% binding agent). 

Strontium discharged into the atmosphere from the operation of coal fired power plants depends on the strontium concentration in coal, the amount of coal burned, and the efficiency of fly ash recovery. Approximately 90% of coal mass is consumed during the combustion process, leaving 10% as a residual nonvolatile material (fly ash) containing 100-4,000 ppm Strontium (or mg/kg) (Furr et al. 1977). Atmospheric concentrations of strontium emitted from coal fired power plants have been found to range from 17 to 2,718 mg/m3 in the western United States and are approximately 9,786 mg/m3 in the eastern United States (Ondov et al. 1989 Que Hee et al. 1982). Phosphate fertilizers are known to contain between 20 and 4,000 pg strontium/g solid by weight (Lee and von Lehmden 1973 Raven and Loeppert 1997). Strontium can be released into the atmosphere in windblown soil to which phosphate fertilizers have been applied. Pyrotechnic displays release low levels of strontium on the order of 5 mg/m3 in the immediate environment of the display (Perry 1999). 

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