Explosion hazards and fire risk
Ammonium nitrate for vibration, shock or friction is not sensitive , not to spontaneous combustion performance . Therefore, the use and production of ammonium nitrate , just to comply with certain safety regulations , in general, is relatively safe .
Explosive ammonium nitrate is mainly caused by the following reasons :
( 1 ) thermal decomposition of pure ammonium nitrate ;
( 2 ) the intense enough fuze ;
( 3 ) thermal decomposition of organic substances when present ;
( 4 ) and some inorganic impurities Effect of metal powder.
Thermal decomposition of ammonium nitrate : heated continuously at 110 ℃, pure ammonium nitrate ,
the decomposition of the following formula : NH4NO3 = HNO3 + NH3-41300 Card belong to the thermal effect of the solid salt . Molten nitrate decomposition process endothermic 37.0 kcal. When at 185 ~ 200 ℃ decomposed, nitrous oxide and water : NH4NO3 = N2O +2 H2O +30300 card
or more from the start temperature of 230 ℃ , decomposition speed, while a weak flash to occur. At this point the following formula is decomposed into nitrogen and oxygen : 2NH4NO3 = 2N2 + O2 +4 H2O when ammonium nitrate ( gas ) +30700 card in a molten state here type decomposition heat release is 35 kcal. If at this time the decomposition is carried out in a fixed accommodate , then the temperature and pressure of up to 550 ℃ and 4500 kg / cm 2 . In the case of rapid heating , the reaction can also be carried out by the following formula : 2NH4NO3 = 2NO + N2 +4 H2O ammonium nitrate + 9200 cards in a molten state heat release is 13.0 kcal. 33.5 kcal exothermic when 4NH4NO3 = 3N2 +2 NO2 +8 H2O +29500 card ( 5 ) molten nitrate decomposition formula here : When the temperature is higher than 400 ℃, according to the following reaction formula decomposition and exploded . May also occur at this temperature the following reaction : 3NH4NO3 = N2O3 +2 N2 + 6H2O ( gas ) +23300 card ( 6 )
27.0 kcal molten nitrate exothermic decomposition . When there is the presence of platinum sponge -like reaction proceeds as follows : 5NH4NO3 = 2HNO3 +4 H2 +9 H2O +33400 card ( 7 ) molten ammonium nitrate reaction was exothermic 37.5 kcal. When the explosion, the overall reaction may be ammonium nitrate decomposition in the formula below : 8NH4NO3 = 2NO2 +4 NO +5 N2 +16 H2O (8) In general , all the above equation may occur when ammonium nitrate decomposition. But in fact the decomposition reaction is not also be in accordance with all of the equations . Due to the different conditions , the reaction may be the main one , but several other reactions proceeded fewer side effects. Ammonium nitrate does not contain impurities burning , the burning quickly stopped because the amount of heat required for the decomposition reaction of the exothermic heat of combustion ratio to be more ( at a temperature below 260 ℃, decomposition of ammonium nitrate overall process is endothermic ) , so that because of insufficient supply of heat . When packaged in a bag of ammonium nitrate melt and burn a part of the finished product will be burned . When the temperature is high enough , the fire caused by the organic combustible exacerbated by the presence of ammonium nitrate . It is noteworthy that the concept on the thermal decomposition of ammonium nitrate , ammonium nitrate, people often start with the concept of the generated gases start to decompose confuse this concept , which is inaccurate , because , strictly speaking , ammonium nitrate starts to generate gas at a temperature well below the the temperature , the speed corresponding to the dissociation , and the dissociation process is a decomposition process . As one , two stage evaporator ammonium nitrate solution in the production process , in which only the negative pressure 90 ~ 130 ℃, when the ammonium nitrate solution was evaporated until neutral , after heating evaporation, the ammonium nitrate solution Serve acidity. In the evaporation process , the prolonged heating temperature at a certain time or under certain heating time constant heating temperature , then heated by evaporation of the acidity of the ammonium nitrate solution to increase . This is due to the dissociation of the ammonium nitrate is greater than the diffusion rate of the ammonia vapor diffusion rate of nitrate.Ammonium nitrate for vibration, shock or friction is not sensitive , not to spontaneous combustion performance . Therefore, the use and production of ammonium nitrate , just to comply with certain safety regulations , in general, is relatively safe . Explosive ammonium nitrate is mainly caused by the following reasons : ( 1 ) thermal decomposition of pure ammonium nitrate ; ( 2 ) the intense enough fuze ; ( 3 ) thermal decomposition of organic substances when present ; ( 4 ) and some inorganic impurities Effect of metal powder. Thermal decomposition of ammonium nitrate : heated continuously at 110 ℃, pure ammonium nitrate , the decomposition of the following formula : NH4NO3 = HNO3 + NH3-41300 Card ( 1 ) belong to the thermal effect of the solid salt . Molten nitrate decomposition process endothermic 37.0 kcal. When at 185 ~ 200 ℃ decomposed, nitrous oxide and water : NH4NO3 = N2O +2 H2O +30300 card ( 2 ) or more from the start temperature of 230 ℃ , decomposition speed, while a weak flash to occur. At this point the following formula is decomposed into nitrogen and oxygen : 2NH4NO3 = 2N2 + O2 +4 H2O when ammonium nitrate ( gas ) +30700 card ( 3 ) in a molten state here type decomposition heat release is 35 kcal. If at this time the decomposition is carried out in a fixed accommodate , then the temperature and pressure of up to 550 ℃ and 4500 kg / cm 2 . In the case of rapid heating , the reaction can also be carried out by the following formula : 2NH4NO3 = 2NO + N2 +4 H2O ammonium nitrate + 9200 cards ( 4 ) in a molten state heat release is 13.0 kcal. 33.5 kcal exothermic when 4NH4NO3 = 3N2 +2 NO2 +8 H2O +29500 card ( 5 ) molten nitrate decomposition formula here : When the temperature is higher than 400 ℃, according to the following reaction formula decomposition and exploded . May also occur at this temperature the following reaction : 3NH4NO3 = N2O3 +2 N2 + 6H2O ( gas ) +23300 card ( 6 )
27.0 kcal molten nitrate exothermic decomposition . When there is the presence of platinum sponge -like reaction proceeds as follows : 5NH4NO3 = 2HNO3 +4 H2 +9 H2O +33400 card ( 7 ) molten ammonium nitrate reaction was exothermic 37.5 kcal. When the explosion, the overall reaction may be ammonium nitrate decomposition in the formula below : 8NH4NO3 = 2NO2 +4 NO +5 N2 +16 H2O (8) In general , all the above equation may occur when ammonium nitrate decomposition. But in fact the decomposition reaction is not also be in accordance with all of the equations . Due to the different conditions , the reaction may be the main one , but several other reactions proceeded fewer side effects. Ammonium nitrate does not contain impurities burning , the burning quickly stopped because the amount of heat required for the decomposition reaction of the exothermic heat of combustion ratio to be more ( at a temperature below 260 ℃, decomposition of ammonium nitrate overall process is endothermic ) , so that because of insufficient supply of heat . When packaged in a bag of ammonium nitrate melt and burn a part of the finished product will be burned . When the temperature is high enough , the fire caused by the organic combustible exacerbated by the presence of ammonium nitrate . It is noteworthy that the concept on the thermal decomposition of ammonium nitrate , ammonium nitrate, people often start with the concept of the generated gases start to decompose confuse this concept , which is inaccurate , because , strictly speaking , ammonium nitrate starts to generate gas at a temperature well below the the temperature , the speed corresponding to the dissociation , and the dissociation process is a decomposition process . As one , two stage evaporator ammonium nitrate solution in the production process , in which only the negative pressure 90 ~ 130 ℃, when the ammonium nitrate solution was evaporated until neutral , after heating evaporation, the ammonium nitrate solution Serve acidity. In the evaporation process , the prolonged heating temperature at a certain time or under certain heating time constant heating temperature , then heated by evaporation of the acidity of the ammonium nitrate solution to increase . This is due to the dissociation of the ammonium nitrate is greater than the diffusion rate of the ammonia vapor diffusion rate of nitrate.
