Gray powder; [MSDSonline]
Average phosphorus content is 20-27%; Produced as a by-product of yellow phosphorus manufacturing; Used in foundries (improve flow properties) and steel industry (improve machinability); [Ullmann]
May release phosphine gas when reacts with acid or heated to decomposition; [MSDSonline] Irritating vapors containing phosphorus oxides or phosphoric acid may be released in a fire. [CAMEO] See "PHOSPHIDES."
Industrial Processes with risk of exposure: