Amax Incorporated

USA As Represented by Secretary of the Navy

Qual-chem Limited

William A May

William A Ferrando

Amarnath P Divecha

Subhash D Karmarkar

James M Kerr

Scott M Hoover

John M Laferty, Jr

Roger F Sebenik

Pablo P LaValle

Mahesh C Jha

The present invention provides a method for fluidized bed roasting of molybdenite to molybdenum trioxide. A fluid bed reactor separated into separate zones is used to provide plug flow conditions. A cooling tube is submerged in the fluid bed to control temperature. A vibrator is used to enhance fluidization.

Fluidized-bed roasting of molybdenite concentrates

A predetermined quantity of a metal-matrix composite material is injected to a heating crucible along an angular infeed direction toward a location therein at which a vortex is formed by the blade of an agitator through which the material is stirred while being superheated above the melting temperature to a pouring temperature under which the melted material is transferred to a casting mold after surface skimming thereof to form a product having improved wear resistance properties.

Fabrication of metal-matrix compositions

Flowable molybdenum metal powder of controlled particle size distribution is produced by stage-wise reduction wherein, in a first stage, molybdenum trioxide feed is preferably introduced at depth in a fluid bed of molybdenum dioxide and is reduced in an atmosphere containing at least 50% hydrogen, by volume, at a temperature between 560.degree. and 620.degree. C. and the product molybdenum dioxide is then reduced to molybdenum metal in a second stage fluid bed at a temperature between 1025.degree. C. and 1075.degree. C. in an atmosphere containing at least 50% hydrogen employed in amount of at least 2.75 times stoichiometric while controlling the off-gas dewpoint to be at least 21.degree. C. and controlling the off-gas hydrogen:water vapor ratio so as not to exceed 24:1 and removing the product spheroidal molybdenum metal particles from the bottom of the bed to prevent collapse of the bed.

Fluid bed reduction to produce flowable molybdenum metal

A process is provided for igniting a mixed powder material compact containing sufficient fuel to support an exothermic reaction between ingredients contained in the compact. The ignition is achieved in an inert atmosphere with an electric arc produced by an electrode without contacting the compact and thereby initiating the reaction.

Ignition of sustained high temperature synthesis reactions

A process is provided for recovering metal values from spent hydrodesulfurization catalyst, the process comprising forming in a pressure reactor an aqueous slurry of finely divided spent catalyst and sodium carbonate, the spent catalyst containing by weight about 2 to 10% Mo, up to about 12% V (e.g., about 2 to 10%), about 0.5 to 4% Co, up to about 10% Ni (e.g., about 0.5 to 5%), occluded oil, coke, sulfide sulfur and the balance essentially alumina. The amount of sodium carbonate employed is at least sufficient under oxidizing conditions to convert molybdenum and any vanadium present to soluble Na.sub.2 MoO.sub.4 and NaVO.sub.3 and to neutralize SO.sub.3 produced during oxidation, the amount of sodium carbonate being at least that required stoichiometrically. The slurry is heated to a temperature of about 200.degree. C. to 350.degree. C. (e.g., 275.degree. C. to 325.degree. C.) and a pressure of about 800 psig to 2500 psig (e.g., about 1500 psig to 2500 psig) for a time at least sufficient to solubilize the molybdenum and vanadium present, the amount of oxygen employed being over about 1.1 times the stoichiometric amount sufficient to oxidize the metal values and sulfur to the maximum oxidized state, and to oxidize the oil and free carbon to CO.sub.2 and H.sub.2 O. The solubilized Mo and V are thereafter separated from each other.

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Boulder, CO, United States of America

William A May