2009-3-31 11:51
jan4075
叠氮化钠本身是很稳定的,除非你把他和铅,铜银等金属盐混在一起,那就可要出问题了<br />请参考如下内容<br />Sodium azide is insensitive but highly toxic. Contact must be avoided with acid, from which the dangerous hydrazoic acid forms, and copper, lead, cadmium, silver, mercury, or their alloys, from which sensitive azides may be formed. Nucleating agents, such as poly(vinyl alcohol) (PVA), sodium carboxymethylcellulose (CMC), or dextrin, may be added during precipitation to produce free-flowing crystals or rounded agglomerates required for the large-scale, automatic loading of detonators. The presence of hydrophilic polymeric substances also tends to eliminate the small possibility of spontaneous explosions occurring during the precipitation process. Wetting agents may also be added.<br />All phases of the manufacturing process are conducted by remote control in stainless steel vessels using either distilled or demineralized water and filtered solutions. The overall precipitation time is about 60 minutes. In the manufacture of dextrinated lead azide, lead nitrate stock solution is prepared by dissolving lead nitrate, dextrin, and sodium hydroxide in water at pH 4.6-4.8. The solution is cooled, filtered, pumped to a storage tank, and allowed to settle for eight hours or longer. A sodium azide stock solution is similarly prepared. The precipitation vessel is a precisely made, open-topped, round-bottom, double-walled, polished stainless steel tilting pot equipped with an agitator, feed tubes, and a water spray ring. The lead nitrate solution at 60癈 is transferred to the precipitation vessel from a measuring tank, and the sodium azide solution is added at a rate of about 2 L/min while maintaining the 60癈 temperature. Lead azide precipitates as free-flowing, fine white agglomerates. After settling, the mother liquor is decanted through a filter, collected, and neutralized using 30% sodium nitrate and then 30% nitric acid, or using ceric ammonium nitrate to decompose the azide ion. Excess acid is neutralized using soda ash. Any soluble lead is precipitated as the insoluble carbonate. The lead azide precipitate is washed repeatedly with water, vacuum filtered, and dried. Lead azide made without dextrin (RD 1333) usually contains more than 99% azide. When made with dextrin it contains about 92% lead azide, 4-5% lead hydroxide, 3% dextrin, and other impurities. Lead azide must be free of needle-shaped crystals longer than 0.1 mm. Dextrinated lead azide is less sensitive but is somewhat more hygroscopic, less dense, and less efficient as an initiator than the 99% product.<br />A low incidence of explosions has been reported when precipitation is effected without a nucleating agent and during the screening process. Precautions must be taken during detonator loading to prevent dusting and to maintain a scrupulously clean operation.