Molten salt hazardous waste disposal process utilizing gas/liquid contact for salt recovery

Claim 2

A process for concentrating a plutonium-containing waste material which comprises: combusting said plutonium-containing waste material in a molten salt comprising an alkali metal carbonate; recovering from said combustion a gaseous product having a temperature in the range of about 700°-1000° C. and a melt containing spent alkali metal carbonate and plutonium oxide; dissolving said melt to form a slurry containing a mixture of ash and plutonium oxide in an alkali metal carbonate solution; separating said mixture of ash and plutonium oxide from said slurry; recovering plutonium values from said mixture; introducing the solution from which said mixture of ash and plutonium oxide have been separated into spray contact with said gaseous product in a spray drying zone; separating from said spray drying zone a cooled gaseous product having a temperature in the range of about 50°-250° C., and a solid, flowable product containing alkali metal carbonate; separating said solid, flowable product from said cooled gaseous product; and recycling said solid, flowable product to said molten salt.

Claim 3

A process according to claim 1 wherein said plutonium values are recovered by means of a process which comprises: leaching said mixture of ash and plutonium oxide with a mineral acid; separating the resulting soluble plutonium salt from said ash; purifying said soluble plutonium salt by means of an ion exchange treatment; and calcining the purified soluble plutonium salt to recover dry plutonium dioxide product.

Claim 4

A process according to claim 1 wherein said plutonium values are recovered by means of a process which comprises: leaching said mixture of ash and plutonium oxide with a mineral acid; separating the resulting soluble plutonium salt from said ash; purifying said soluble plutonium salt by means of an ion exchange treatment; converting the purified soluble plutonium salt to an insoluble plutonium oxalate; and calcining said plutonium oxalate to recover dry plutonium dioxide product.

Claim 5

A process according to claim 1 wherein said solid, flowable product is separated from said cooled gaseous product by means of filtration.

Claim 6

A process for minimizing the volume of disposable waste resulting from the combustion of a hazardous waste in a molten salt comprising an alkali metal carbonate which comprises: withdrawing at least a portion of a spent melt produced in the combustion of a hazardous waste in a molten salt; mixing the withdrawn spent melt with an aqueous quenching medium to produce a slurry containing insoluble inorganic compounds of metals present in said hazardous waste in an aqueous solution comprising an alkali metal carbonate; separating said insoluble inorganic compounds from said slurry; spray drying the resulting alkali metal carbonate solution in a spray drying zone containing a hot gas produced in the combustion of said hazardous waste; recovering from said spray drying zone a mixture of a cooled gas and a dry, flowable solid comprising an alkali metal carbonate; separating said dry, flowable solid from said cooled gas; and recycling said dry, flowable solid to said molten salt.

Claim 7

A process for minimizing the volume of disposable waste resulting from the combustion of a hazardous waste in a molten salt comprising an alkali metal carbonate which comprises: withdrawing at least a portion of a spent melt produced in the combustion of a hazardous waste in a molten salt; mixing the withdrawn spent melt with an aqueous quenching medium to produce a slurry containing insoluble inorganic compounds of metals present in said hazardous waste in an aqueous solution comprising an alkali metal carbonate; separating said insoluble inorganic compounds from said slurry; spray drying the resulting alkali metal carbonate solution in a spray drying zone containing a hot gas produced in the combustion of said hazardous waste; recovering from said spray drying zone a mixture of a cooled gas and a dry, flowable solid comprising an alkali metal carbonate; separating said dry, flowable solid from said cooled gas; and recycling said dry, flowable solid to said molten salt.

Claim 8

A process for disposing of a hazardous waste which comprises: introducing a hazardous waste and a source of gaseous oxygen into a molten salt comprising an alkali metal carbonate; maintaining said molten salt at a temperature in the range of about 700°-1000° C. and a pressure within the range of about 0.5 to 10 atmospheres to thereby produce a hot gaseous product comprising carbon dioxide and water vapor and a spent melt containing metallic compounds and inorganic ash; withdrawing at least a portion of said spent melt; quenching the withdrawn spent melt with an aqueous solution to produce a slurry containing insoluble metallic compounds and inorganic ash in an aqueous solution comprising an alkali metal carbonate; separating said insoluble metallic compounds and said inorganic ash from said slurry; disposing of said insoluble metallic compounds and said inorganic ash; contacting the resulting alkali metal carbonate solution in the form of a spray with said hot gaseous product to cool said hot gaseous product to a temperature in the range of about 50°-250° C. and to form from said alkali metal carbonate solution a dry, flowable solid; filtering said dry, flowable solid from the cooled gaseous product; and recycling said dry flowable solid to said molten salt.

Claim 9

A process for disposing of a hazardous waste which comprises: introducing a hazardous waste and a source of gaseous oxygen into a molten salt comprising an alkali metal carbonate; maintaining said molten salt at a temperature in the range of about 700°-1000° C. and a pressure within the range of about 0.5 to 10 atmospheres to thereby produce a hot gaseous product comprising carbon dioxide and water vapor and a spent melt containing metallic compounds and inorganic ash; withdrawing at least a portion of said spent melt; quenching the withdrawn spent melt with an aqueous solution to produce a slurry containing insoluble metallic compounds and inorganic ash in an aqueous solution comprising an alkali metal carbonate; separating said insoluble metallic compounds and said inorganic ash from said slurry; disposing of said insoluble metallic compounds and said inorganic ash; contacting the resulting alkali metal carbonate solution in the form of a spray with said hot gaseous product to cool said hot gaseous product to a temperature in the range of about 50°-250° C. and to form from said alkali metal carbonate solution a dry, flowable solid; filtering said dry, flowable solid from the cooled gaseous product; and recycling said dry flowable solid to said molten salt.