Abstract: Elemental phosphorus contained in waste ponds can be appropriately passivated to render them substantially less pyrophoric by bringing the elemental phosphorus-containing wastes into contact with an oxygen-containing gas. Substantially pure oxygen can be used to appropriately sparge the elemental phosphorus-containing wastes submerged in the waste pond. If desired, phosphorus values can be recovered in the form of an aqueous phosphate solution.

Abstract: A process for treating a pyrophoric P.sub.4 -containing material to convert it to a substantially non-pyrophoric P.sub.2 O.sub.5 material is described. The process comprises supplying streams of fluid P.sub.4 -containing material and an oxygen-containing gas to a reactor filled with water. The P.sub.4 -containing material and the oxygen and the oxygen-containing gas react with one another after both have entered the aqueous medium within the reactor to thereby form the desired P.sub.2 O.sub.5 material.

Abstract: A method of decontaminating a location containing pyrophoric P.sub.4 -contamination is described. It comprises bringing to the location a portable vehicle which comprises at least one of the necessary items needed to accomplish the contacting of the P.sub.4 -contaminated material, while it is under a protective blanket of a nonflammable fluid, with an oxygen-containing gas, such as air, pure oxygen, or mixtures thereof. The portable vehicle may contain, for example, a scrubber, a source of oxygen, a pump, means to convey the oxygen-containing gas to the P.sub.4 -contaminated material, and means to convey any effluent resulting from the treatment to suitable recovery or treatment apparatus.

Abstract: Pyrophoric elemental phosphorus-containing material, e.g., solid waste containing high levels of elemental phosphorus (P.sub.4), is treated by contact with an oxygen-containing gas, such as air, to reduce the amount of elemental phosphorus contained therein while it is otherwise protected from contact with oxygen in the air by being blanketed by a non-flammable fluid (e.g., while under an aqueous protective layer). This renders the material less pyrophoric and also enables the recovery of phosphorus values therefrom, e.g., in the form of a weak phosphoric acid solution. This treatment, for example, mobilizes highly pyrophoric solid waste into a more flowable sludge or mud form while rendering it substantially more non-pyrophoric.