Patented July 10, 1951 2,559,684

UNITED STATES PATENT OFFICE 2,559,684 STABILIZING RED Sol Skolnik, Inyokern, Calif., and Grover L. Bridger, Ames, Iowa, assignors to Tennessee Walley Authority, a corporation of the United States No Drawing. Application April 27, 1949, Serial No. 90,035 3 Claims. (C. 23-223) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 C. G. 75) 2 The invention herein described may be manu are ineffective for stabilizing red phosphorus factured and used by or for the Government for against accidental ignition due to impact and governmental purposes without the payment to friction. us of any royalty therefor. It is highly desirable that some method be pro This invention reiates to improved methods vided which will stabilize red phosphorus against for stabilizing red phosphorus against ignition accidental ignition under the influence of im caused by impact or friction, particularly effec pact and friction, and which will leave red phos tive in stabilizing freshly prepared red phos phorus powder in an apparently dry and free phorus against the hazards of impact or friction flowing. State. It is also desirable that any such ordinarily encountered in handling or shipping 10 method should leave no foreign substance in the the dry material. red phosphorus which is not easily removable by Although red phosphorus is a relatively stable simple Washing With water. It is also desirable material as compared with yellow phosphorus, that a method be provided which not only re the handling and shipping of red phosphorus are duces the danger of ignition of red phosphorus attended by a number of hazards. Red phoS 15 under impact or the influence of friction, but phorus does not ignite Spontaneously on expoSUlre which also retards oxidation of traces of yellow to air unless it contains appreciable traces of phosphorus which are frequently present. yellow phosphorus. Such traces of yellow phos. It is an object of this invention to provide a phorus are frequently present in freshly manu method for stabilizing finely divided red phos factured red phosphorus. Even Substantially 20 phorus against ignition under impact or the in pure red phosphorus can be easily ignited when fluence of friction and which will leave such red it is handled in Such manner that there is Sub phosphorus powder in an apparently dry and stantial impact on the mass of particles or con free-flowing state. - siderable friction is imposed upon them. Such Another object is to provide such method which conditions are frequently encountered in the 25 will not result in the incorporation of any mate packaging and shipping of red phosphorus SO rial in stabilized red phosphorus which is not that the danger of fire is always present. easily removable by simple washing with water. it has long been known that red phosphorus Another object is to provide an apparently dry, slowly oxidizes in the air, and in the presence of free-flowing red phosphorus powder stabilized moisture normally present in air, phosphoric acid 30 against ignition under impact or the influence of is formed. This is shown by A. W. Melor's friction. treatise on Inorganic and Theoretical Chemistry, Other objects and advantages will become ap vol. 8,772 (1928). Upon such exposure to air with parent as this disclosure proceeds. partial oxidation and formation of phosphoric We have now found that finely divided red acid, a mass of finely divided red phosphorus be phosphorus normally susceptible to ignition under comes moistened with hygroscopic acid and cakes the influence of impact and friction may be sta into a mass which is difficult to handle. bilized by depositing a small quantity of a mate So far as is known, there are no methods dis rial selected from the group consisting of phos closed in the prior art for reducing the danger phorus pentoxide, phosphorus trioxide, highly of ignition of red phosphorus under impact or concentrated phosphoric acid, highly concen friction. In fact, for most uses, it is desired