Amax Incorporated

Other

Malcolm T Hepworth

Bruce J Sabacky

Dale K Huggins

Mahesh C Jha

John M Laferty, Jr

Gordon R Wicker

John M Laferty

Antonio E Blandon

Rachid Ben-Slimane

Lorin D Reddin

Lawrence F McHugh

Glenn D Welch

Methods of recovering manganese in the form of manganese carbonate from ores containing manganese and iron while also removing substantially all of the iron contained in the sulfurous acid leach solution are disclosed.

Recovery of manganese from leach solutions

Durable, porous sulfur sorbents useful in removing hydrogen sulfide from hot coal gas are prepared by water pelletizing a mixture of fine zinc oxide and fine iron oxide with inorganic and organic binders and small amounts of activators such as sodium carbonate and molybdenite; the pellets are dried and then indurated at a high temperature, e.g., 1800.degree. C., for a time sufficient to produce crush-resistant pellets.

Durable zinc ferrite sorbent pellets for hot coal gas desulfurization

Sulfur-containing coal is combusted in a cyclone furnace under strongly reducing conditions with a sulfur fixing agent such as lime to produce a basic slag containing the ash and sulfur content of the coal and a product gas of high combustible content which may be burned as a fuel gas in a steam generator or otherwise to yield an exhaust gas which does not require scrubbing.

Coal slagging burner for producing clean low-sulfur fuel gas

A process is provided for combusting sulfur-containing coal in a combustion stage to which is provided at least 60% of the oxygen stoichiometrically required for substantially complete combustion of the coal and combustion is conducted under highly turbulent conditions in a furnace burner cavity to which finely divided iron oxide and/or iron powder is provided and in which a high heat release rate is maintained to form a liquid iron oxysulfide phase which acts to scrub sulfur-containing gaseous species from the combustion atmosphere and is separated from the combustion atmosphere with substantially the sulfur originally contained in the coal. Following separation, the hot fuel gas resulting is burned to completion in a heat exchanging furnace, gas turbine or other energy extracting device.

Coal combustion to produce clean low-sulfur exhaust gas

A process is provided for combusting sulfur-containing coal in a single step while producing an off-gas low in sulfur. The process comprises combusting finely divided coal in a furnace burner cavity in the presence of a finely divided iron oxide or iron powder and at least about 60% of the oxygen stoichiometrically required for substantially complete combustion of the coal to form a liquid iron oxysulfide phase and a turbulent atmosphere of combustion-product gases, liquid iron oxysulfide acting to scrub sulfur-containing gaseous species from the atmosphere to yield an essentially sulfur-free flue gas and a liquid iron oxysulfide slag containing substantially the sulfur originally contained in the coal.

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 is provided for converting MoS.sub.2 to MoO.sub.2 wherein, MoS.sub.2 in particulate form is fed into a reactor while flowing MoO.sub.3 vapor therein to effect reaction thereof with MoS.sub.2 to form MoO.sub.2. The temperature in the reactor is maintained at a level sufficient to cause the reaction to go forward. A portion of the MoO.sub.2 is removed from the reactor as a product and the remainder is selectively oxidized at a temperature sufficient to generate gaseous MoO.sub.3 which is recycled to the reactor relative to the flow of MoS.sub.2 therein to convert the MoS.sub.2 to MoO.sub.2.

Process for the production of molybdenum dioxide

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.

Molybdenum dioxide-molybdenite roasting

An aqueous solution of at least one valuable oxyanion containing molybdenum, tungsten, vanadium, or uranium is refined to lower the content of contaminant anions such as PO.sub.4.sup.-3, SO.sub.4.sup.-2, NO.sub.3.sup.-, Cl.sup.-, ClO.sub.3.sup.-, and ClO.sub.4.sup.-, by subjecting the solution to electrolysis at a pH of from 0.5 to 4.0 between a cation-permselective membrane and an anion-permselective membrane having tertiary amine or quaternary ammonium anion exchange groups, to cause contaminant anions to pass from the solution into the anolyte. Ammonium molybdates, tungstates, vanadates, and uranates are formed from the thus-refined solution by subjecting it to a second stage of electrolysis at a pH of at least 7 between a cation-permselective membrane and an anion-permselective membrane to cause valuable oxyanions to pass from the solution into an anolyte which comprises an aqueous solution of ammonia and to form the desired ammonium compound.

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Golden, CO, United States of America

Malcolm T Hepworth