Kernforschungsanlage Julich Gesellschaft MIT Beschrankter Haftung

Kernforschungsanlage Julich

Vereinigte Aluminum-werke Aktiengesellschaft

Erich Zimmer

Helmut Ringel

Eike Barnert

Hans Langen

Nabil Abdelmonem

Wolfgang Frommelt

Ahmad Nafissi

Paul Morschl

Octave Coenegracht

Peter Proplesch

Kurt Scharf

Gunther Winkhaus

A process for the embedding or containment of waste materials, especially of radioactive waste materials, by embedding in a ceramic matrix through the intermediary of the chemical precipitation of a hydrosol of the matrix, which is formed through the reaction of a nitrate with ammonia or ammonium hydroxide. In this process, the hydrosol is trickled in a pouring column into a precipitation bath, subsequent to the introduction of the material which is to be embedded, in which the hydrosol particles which are formed during the trickling gelatinize into gel particles. The gel particles are removed from the precipitation bath, washed, dried and finally sintered.

Process for the containment of materials in a ceramic matrix through the

An apparatus charges weakly acidic cationic ion exchange resin particles with uranyl ions by contacting the particles stepwise with aqueous uranyl nitrate solution at higher uranium concentrations from stage to stage. An alkaline medium is added to the uranyl nitrate solution in each stage to increase the successive pH values of the uranyl nitrate solution contacting the particles in dependance upon the uranium concentration effective for maximum charging of the particles with uranyl ions.

Apparatus for producing ion exchange particles charged with uranyl ions

The reaction gas throughout of the supply duct feeding gas to the bottom of a fluidized bed reactor of the kind shown in U.S. Pat. No. 4,153,004, issued May 8, 1979, is increased by providing the reaction gas supply tube in the form of a bundle of tubes of small cross-section of about 2 mm diameter. Subdivision of the supply tube into hexagonal ducts in honeycomb arrangement maximizes the useful cross-sectional area of the supply tube. With the smaller elemental tube diameters, a higher rate of flow is maintainable without loss of laminar flow behavior, which behavior is maintained in the jet issuing from the subdivided reaction gas supply duct as it flows towards the constricted entrance into the fluidized bed container while being surrounded by a sheath of inert carrier gas supplied by an annular duct surrounding the reaction gas tube. It is thus possible to increase the input of reaction gas without increasing the diameter of the jet or loss of the laminar flow characteristics necessary to prevent the reaction gas from making deposits that would interfere with the introduction of gas into the bottom of the bed.

Fluidized bed reactor with open reaction gas input and method of

Weakly acidic cationic ion exchange resin particles are charged with uranyl ions by contacting the particles step wise with aqueous uranyl nitrate solution at higher uranium concentrations from stage to stage. An alkaline medium is added to the uranyl nitrate solution in each stage to increase the successive pH values of the uranyl nitrate solution contacting the particles in dependence upon the uranium concentration effective for maximum charging of the particles with uranyl ions.

Method of producing weakly acidic cation exchange resin particles

In a fluidized bed reactor total gas feed is through a constricted opening at the bottom of the reactor. A carrier gas supply duct communicates with said bottom. A reaction gas supply tube, disposed within said duct, has an outlet spaced from said bottom and is comprised of a bundle of tubes arranged to dispense an annular stream.

Fluidized bed reactor

A hydrosol containing, in nitrate form, a fuel or fuel-and-breeder material which is projected horizontally in the form of droplets into a gas phase containing gaseous ammonia and allowed to fall in a drip-casting column into a precipitation bath containing ammonium hydroxide. In the gas phase, the droplets are hardened just enough to prevent their deformation upon penetrating into the precipitation bath where the hardening is completed. A falling height of 5 cm is suitable. The granules are washed free of ammonium nitrate, then dried, and then sintered. The heavy metal content in the hydrosol is between 1.5 and 3 moles per liter, and the pH value of the precipitation bath is between 8 and 9. The hydrosol contains the heavy metal in oxide form and the process can be used with a thorium oxide hydrosol or a hydrosol that, in addition to thorium oxide, contains the oxide of hexavalent uranium, in the latter case the hexavalent uranium being present in a proportion up to 25% by weight of the total heavy metal. The process is also applicable to producing kernels of mixed thorium and plutonium oxides. In the case of uranium-containing granules, the sintering step is carried out in a reducing atmosphere to convert the uranium to the tetravalent state.

Hydrosol droplet casting process for production of nuclear fuel and

Radiation-contaminated ammonium nitrate is heated in solution to about 100.degree. C. in the presence of finely powdered calcium oxide or lithium hydroxide. Ammonia and water vapor are given off leaving an alkaline or alkaline earth nitrate which can then be safely decomposed by calcination into a metal oxide and oxides of nitrogen. The metal oxide can be recycled in a continuation of the process. The oxides of nitrogen can be passed through water to produce nitric acid useable in dissolving oxides of fissionable materials and the ammonia may be used in aqueous solution to react with nitrates of nuclear fuel or breeder metals in the very process that produces the by-product ammonium nitrate. Thus, all by-products and reagents can be reconverted and recycled.

Process for recovering useable products from by-product ammonium nitrate

A method of making metallic oxide or carbide particles of uranium, which prises fuels or breeder materials for nuclear reactors. An aqueous solution of uranyl nitrate or chloride and, if necessary, colloidal carbon is added dropwise into an organic ketone or ketone mixture phase which is located above an aqueous ammonia solution. The thereupon formed particles are sintered.

Method of making metallic oxide or carbide particles

The red mud by-product of the Bayer process by which aluminum oxide is reed from bauxite as an aluminate, is digested with concentrated sulfuric acid or with sulfur trioxide gas to produce sulfates that can be leached out to the resulting mass with water. The solution is then heated at a pH of 1 to precipitate titanium oxide hydrate by hydrolysis. The remaining sulfates of the solution are then obtained in solid form by evaporation, or by precipitation with acetone, and the solid is then roasted to convert the aluminum and iron to the oxide. After leaching out the sodium sulfate with water, the aluminum and iron oxide are separated by the Bayer process, which works in this case even though x-ray diffusion patterns show that the aluminum oxide is mainly .alpha.Al.sub.2 O.sub.3.

Reclamation treatment of red mud

After separating brine from the slime and drying the same with solids therein, dried solids are subjected to roasting in an oxydizing temperature of 350.degree. to 400.degree. C, and then leaching the roasted material with predetermined acid and withdrawing sulfur oxides from waste gases generated during the roasting step.

Method for recovering non-ferrous metals from hydro-thermal slime

A method of regenerating fuel and/or breeder elements with thorium as brer material for nuclear reactors. The fuel and/or breeder material is dissolved in an acid such as nitric acid, sulfuric acid or the like and the thus obtained solution is subjected to a liquid-liquid reaction with an extraction substance such as tributyl phosphate dissolved in an organic solvent. The fuel material and breeder material are enriched in the organic phase and the fission products remain in the aqueous phase, whereafter the fuel material and/or breeder material are converted into oxides, carbides etc. Prior to the above mentioned liquid-liquid extraction, the acid solution containing the fuel material and/or breeder material is passed over a sorption column in such a way that the number of mols of adsorbed .sup.233 Pa per time unit equals the number of mols of .sup.233 Pa disintegrating per time unit in the sorption column to form .sup.233 U.

Method of reprocessing fuel and/or breeder material containing thorium

A method of making spherical metallic oxide and metallic carbide particles, especially particles consisting of fuel or breeder material for nuclear reactors such as oxide or carbide compounds of uranium, plutonium, thorium and the like with a diameter of from 0.1 to 1.5 millimeters, according to which an aqueous solution of a metallic nitrate or a metallic chloride or a mixture of metallic nitrates or metallic chlorides in which the metallic ions and anions are in a stoichiometric ratio to each other, is added dropwise to an organic phase. The method according to the invention is characterized primarily in that the drops formed from said aqueous solution after congealing, are washed in an aqueous solution containing ammonia and from 0.001% to 0.1% of a non-ionic surface active agent, especially an ethylene oxide condensate, enveloping said particles and preventing them from clumping during the following drying step, drying the thus hardened particles in an air current having a temperature of from 150.degree. to 300.degree.C and an atmospheric moisture content corresponding to the degree of saturation of the air at a temperature of about from 20.degree. to 50.degree.C, and sintering the thus dried particles at about 1300.degree.C.

Growing community of inventors

Julich, Germany

Erich Zimmer