Method and apparatus for recovery of molybdenum from spent catalysts

Abstract

This invention relates to an apparatus and process that utilizes high-temperature oxidation and sublimation for recovery of molybdenum from spent catalysts or other feedstocks that contain molybdenum. One embodiment uses a counter-rotating vortex reactor and a cyclonic entrained-flow reactor to rapidly heat and oxidize the spent catalyst feedstock, such as carbon, sulfur, and molybdenum compounds, at temperatures in the range of about 2100 DEG F to 2900 DEG F, resulting in a gas-solid stream containing molybdenum trioxide vapor. A high-temperature cyclone separator is utilized to separate the residue from this stream before this stream is rapidly quenched to a temperature sufficient to effect condensation of solid molybdenum trioxide without condensing arsenic or phosphoric oxides. The condensed molybdenum trioxide material is separated from this stream by passing through a high-temperature filtration system. The remaining gaseous stream is ducted to operations for possible further material reclamation and entailed pollution control prior to discharge to the atmosphere.

Description

technical field [0001] The present invention relates to the recovery of molybdenum from spent catalyst material, and more particularly to the recovery of molybdenum as molybdenum trioxide. Background technique [0002] Spent catalyst material is typically virgin catalyst material (commonly including molybdenum, tungsten, aluminum, cobalt, nickel, and sulfur) that has impaired catalytic activity due to contamination by materials (such as carbon, iron, vanadium, arsenic, compound) constitutes. [0003] The value of molybdenum contained within spent catalyst materials has made the recovery of molybdenum from these materials an important source of molybdenum, leading to the development of processes to recover this valuable commodity. [0004] Many of these recovery methods, such as those described in US Pat. ,in: [0005] The spent catalyst is calcined or partially gasified (to remove coke and carbon; typically in a humid atmosphere of 850°F to 1650°F), typically with an alka...

AI Technical Summary

Problems solved by technology

Although this is possible, this low temperature places a significant limit on the maximum volume fraction of this molybdenum trioxide in the gas phase, since the vapor pressure of molybdenum trioxide at 1350°F is only about 0.001 atmospheres

Maintaining such a low concentration of molybdenum trioxide in this vapor stream seriously affects the operational efficiency and strength of the process

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