L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des

Bernard Jamonet

Pierre Karinthi

Alain Rigouard

Jean Duc

Jean-Pierre Bouchez

A solution of hydride in liquid nitrogen, the hydride being one that is in gaseous phase at atmospheric pressure and ambient temperature. The concentration of hydride in the liquid nitrogen is comprised between 0.05 and 10 mol %, preferably between 0.05 and 2 mol %, and more preferably between 0.1 and 0.3 mol %. The hydride is selected from the group consisting of arsine, germane, phosphine (PH.sub.3), diborane and silane (SiH.sub.4) and is preferably silane. Atmospheres prepared from these solutions are useful in the thermal treatment of metals, or for surface treatment, particularly of polymeric or metallic surfaces.

Dilute solution of a hydride in liquid nitrogen

In a sludge thickener, supernatant fluid is drawn off via peripheral ducts and oxygenated at a suitable location. The supernatant fluid is thereafter reintroduced into the thickener via diffusers distributed transversely of the thickener and intermediate the peripheral ducts. The generation of nauseating smells is thereby prevented, and an advantageous increase of the concentration of the sludges is attained.

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Bourg de Peage, France

Bernard Jamonet