Contact ignition

Sodium chlorite in contact with sulfuric acid does not generate heat if the quantity is small. However, it can ignite from accumulated heat if the quantity is large. Table 4.7 shows contact reactions of oxidizers with combustibles other than ethylene glycol. 

Sodium peroxide Chromium trioxide Potassium permanganate Bleaching powder 

Cesium nitrate Strontium nitrate Sodium nitrite Smoke Smoke Smoke Sodium bromate Potassium bromate Sodium iodate Smoke Smoke Smoke 

Bleaching powder Sodium chlorite Sodium chlorate Potassium chlorate Barium chlorate Silver chlorate Ignition Ignition Ignition Ignition Ignition Ignition Sodium chromate Potassium chromate Ammonium dichromate Sodium dichromate Potassium dichromate Barium peroxide Smoke Smoke Smoke Smoke Smoke Smoke to 

Bleaching powder (effective Cl 30%) Sodium chloride Sodium chlorate Silver chlorate Sodium nitrite Sodium nitrate Ammonium nitrate Mercury (Il)nitrate 

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Contact ignition by a block 212-242 14 Figure 3 curve 4 jq22-38 47.7... 

Contact ignition by a block in which smoothfaced samples are rapidly brought into contact with a massive hot A1 block and induction times are determined at different block temps Ignition by a flow of gas (sic) in which sample cylinders of various diameters are introduced into a hot gas stream with the cylinder axis normal to the gas flow. Induction times are measured for varying gas compns and temps Results obtained.in Refs 14 15 are summarized in Table 4. Here the columns labelled Equation No and Figure No refer to Merz-hanov s article (Ref 14)... 

Table 4.5 Instances of Contact Ignition between Oxidizers and Ethylene Glycol at Normal Temperature by Improved Steel Dish Test(l)...

Table 4.6 Instances of Contact Ignition/Smoking between Mixtures of Oxidizer, Ethylene Glycol and Sulfuric Acid, According to Improved Steel Dish Test(3)... 

Electrical contacts for high-frequency switching (W). Tungsten is an ideal contact material for switches with high operation frequency, such as car horn contacts, ignition... 

It is a liquid, b,p. 363 K, but if heated it decomposes and hence must be distilled under reduced pressure decomposition may occur with explosive violence and this can occur even at room temperature if impurities are present. Combustible material, for example paper and wood, ignite spontaneously with explosive violence on contact with the acid, and it can produce painful blisters on the skin,... 

Acetone can be handled safely if common sense precautions are taken. It should be used in a weU-ventilated area, and because of its low flash point, ignition sources should be absent. Flame will travel from an ignition source along vapor flows on floors or bench tops to the point of use. Sinks should be rinsed with water while acetone is being used to clean glassware, to prevent the accumulation of vapors. If prolonged or repeated skin contact with acetone could occur, impermeable protective equipment such as gloves and aprons should be worn. 

When dispersed as a dust, adipic acid is subject to normal dust explosion hazards. See Table 3 for ignition properties of such dust—air mixtures. The material is an irritant, especially upon contact with the mucous membranes. Thus protective goggles or face shields should be worn when handling the material. Prolonged contact with the skin should also be avoided. Eye wash fountains, showers, and washing faciUties should be provided in work areas. However, MSDS Sheet400 (5) reports that no acute or chronic effects have been observed. 

Consequendy, convective heat transfer determines the intensity of warming up and ignition. In addition, convective heat transfer also plays an important part in the overall dame-to-surface transmission. The reaction of gases is greatiy accelerated by contact with hot surfaces and, whereas the reaction away from the walls may proceed slowly, reaction at the surface proceeds much more rapidly. 

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