Amax Incorporated

Bandgap Technology Corporation

Bandgap Chemical Corporation

Bruce J Sabacky

Malcolm T Hepworth

Robert E Doane

Semiconductor grade tungsten hexafluoride (WF.sub.6) is produced by reacting tungsten metal with a recirculating flow of gaseous WF.sub.6 containing a small concentration of fluorine in a heated reactor. The high purity WF.sub.6 produced is useful for deposition of tungsten metallization in fabricating VLSI integrated circuitry.

Synthesis of semiconductor grade tungsten hexafluoride

A process and system are provided for flash-roasting molybdenum sulfide containing slag-forming constituents. The process comprises feeding a pneumatically suspended stream of particulate molybdenum sulfide and a mixture of fuel and oxidizing gases through a nozzle into a confined furnace chamber, the fuel gas-oxidizing gas mixture exiting from the nozzle being ignited to provide a flame thereof, the flame being maintained at a condition to provide a temperature in the furnace chamber sufficient to oxidize the molybdenum sulfide and form a volatile gas comprising molybdenum trioxide. The temperature is at least sufficient to melt the slag-forming constituents such that the slag formed is sufficiently liquid to separate from the gaseous mixture and collect at a selected portion of said chamber for removal therefrom. The resulting gases in the volatile molybdenum trioxide are caused to flow from the furnace chamber to and through a condensing chamber, the temperature of the condensing chamber being controlled to condense the volatilized molybdenum trioxide and separate it from the off-gases.

Flash roasting of molybdenum sulfide concentrates in a slagging reactor

A process and system are provided for flash-sublimation of molybdic oxide containing slag-forming constituents. The process comprises feeding a pneumatically suspended stream of particulate molybdic oxide and a mixture of fuel and oxidizing gases through a nozzle into a confined furnace chamber, the fuel gas-oxidizing gas mixture exiting from the nozzle being ignited to provide a flame thereof, the flame being maintained at a condition to provide a temperature in the furnace chamber in excess of that required to sublime molybdic oxide. The temperature is preferably at least sufficient to melt slag-forming constituents contained in said molybdic oxide such that the slag formed is sufficiently liquid to separate from the gaseous mixture and collect at a selected portion of the chamber for removal therefrom. The resulting gases and suspended solids including sublimed molybdenum trioxide are caused to flow from said furnace chamber to and through a condensing chamber, the temperature of the condensing chamber being controlled to above the condensing temperature of the sublimed molybdenum trioxide but below the volatilization temperature of the impurities present and thereby effect a separation of the molybdenum trioxide from the impurities. The separated molybdenum trioxide vapors are then passed to a condenser to condense and recover the molybdenum trioxide as solids and separate it from off-gases.

Flash sublimation and purification of molybdenum oxide

A process is disclosed for roasting molybdenite concentrates directly to molybdenum dioxide. The process comprises establishing a roasting zone having a temperature of about 700.degree. C. to about 800.degree. C., introducing into the roasting zone particulate molybdenum dioxide and molybdenite in a weight ratio of at least about 2:1 along with an oxygen-containing gas in amount sufficient to oxidize the sulfur content of the molybdenite to molybdenum dioxide.

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Westminster, CO, United States of America

Bruce J Sabacky