Method for decomposition of ammonium nitrate in radiochemical production process solutions

FIELD: chemistry.

SUBSTANCE: invention relates to radiochemical technology and can be used in processing of ammonia-containing process solutions and liquid radioactive wastes (LRW) formed during operation radiochemical production. Method for decomposition of ammonium nitrate in radiochemical production process solutions involves heating and correction of solution in nitric acid. Process of decomposition of ammonium nitrate is carried out in a system of nitric and oxalic acids in presence of solid-phase platinum-containing catalyst in dynamic mode in a temperature-controlled column-type apparatus of continuous action.

EFFECT: invention enables quantitative decomposition of ammonium nitrate in process solutions in a wide range of concentrations.

16 cl, 1 dwg, 2 tbl, 2 ex

 



 

Same patents:

FIELD: chemistry.

SUBSTANCE: method of removing 60Co from process solutions of radiochemical plants, relating to medium- and low-activity wastes, is carried out via preliminary heterogeneous catalytic decomposition of organic components contained in the process solutions (liquid radioactive wastes) of radiochemical plants, on a solid-phase catalyst followed by extraction of 60Co from the solutions via coprecipitation thereof with residues of complex cyanides and hydroxides of transition metals (Co, Ni, Zn) and final ion-exchange purification of the filtrate on a cationic-exchange resin (Lewatit MonoPlus TP 207 type).

EFFECT: low residual specific activity of solutions of medium- and low-activity wastes, which enables to change the category of the wastes into non-radioactive wastes.

14 cl, 1 dwg, 6 tbl, 3 ex

FIELD: process engineering.

SUBSTANCE: invention relates to storing of radioactive wastes. Proposed method comprises excavation of pit, arranging of protective barrier in its sides and at its bottom, layer-by-layer laying of wastes with compaction and covering every layer by separating isolating layer. Note here that said protective barrier is made of mortar and polymer film. Note also that said separating and isolating layers are also made of said mortar. Said used mortars contain zeolite, a natural mineral sorbent, as the filler. After laying the top separating isolating layer, surface soil of excavated pit is reclaimed.

EFFECT: ruled out migration of radio nuclides toxic agents in soil, subsurface water and atmosphere.

1 dwg

FIELD: physics, atomic power.

SUBSTANCE: invention relates to atomic power engineering and methods of handling radioactive wastes, particularly methods of fixing pulp in open radioactive waste storage ponds by filling with soil. The method involves dividing the pond with separating dikes which reach the bottom of the pond into regions, dividing the regions between the separating dikes with additional transverse dikes into cells which are filled with soil. A transverse dike is built by pouring soil on ice until the ice sags by a depth which provides a gap between the dike and the bottom of the pond through which the cell is linked through the decantate with the unfilled part of the pond. The decantate is forced under the ice from the cell into the water area of the pond through the gap between the transverse dike and the bottom of the pond by pouring part of the soil intended for filling the cell onto the ice of the cell until the ice sags. After forcing the decantate out of the cell, the cell is insulated from the water area of the pond by building a transverse dike until sagging thereof to the bottom of the pond and the insulated cell is filled with the remaining soil, and the decantate forced out during filling is pumped out.

EFFECT: improved method.

3 cl

FIELD: nuclear energy.

SUBSTANCE: method consists in mixing oil with absorbent, the absorbent being magnesium oxide, finely dispersed carbon, nanoporous carbon material. Then pre-mixed diane epoxy and amine-type solidifier are introduced into the oil- absorbent mix at the ratio of 4:10 and stirred until an even consistency is obtained. The mixture solidifies in a few hours. The solidification over, a layer of absorbent is added to cover the compound and the polymer compound is poured above.

EFFECT: enhanced compound hardness and reduced solidification costs.

1 dwg, 1 tbl, 3 ex

FIELD: power industry.

SUBSTANCE: cementing method of used oils consists in obtaining of cement compound by mixing the oil-containing wastes with cement material. Used oil in quantity of about 20% of the weight of the end compound is pre-bound by means of absorbing material. As absorbing material there used is fly ash of TPP or magnesium oxide, which are taken in "oil:absorbent" weight ratio of 0.5 to 0.7 and 1 to 4. There separately prepared is cement grout by adding the water or low-salt liquid radioactive wastes at cement grout ratio of 0.3 to 0.6 cm3/g of dry mixture containing Portland cement, sorption and plastisising additives, and grout is exposed for some time. Then, oil mixed with absorbent is introduced to it.

EFFECT: invention allows obtaining the compound meeting the normative requirements as to compressive strength, cold resistance, water resistance, which are characterised by absence of oil separation and acceptable setting periods, and high fire- and heat resistance.

1 tbl, 2 ex

FIELD: environment protection; antiseepage barriers preventing natural water pollution with radioactive and toxic materials for waste storage locations.

SUBSTANCE: antiseepage barrier is constructed in aeration zones or in porous water-saturated horizons by forcing gel-forming solution through boreholes. Solution of acid decomposition of ijolite-urtite rock incorporating ions of aluminum, alkali-earth elements, and orthosilicic acid is used as gel-forming solution. 10-15% nitric acid is used for urtite decomposition, rock proportion being as follows: acid, 1 : 10 - 1 : 20; decomposition time, 2-2.5 h; temperature, 40 °C. Antiseepage barrier is obtained due to formation of Si-Ai-Ca-Mg-Fe containing polymer that forms gel directly in vapor space of rock.

EFFECT: facilitated construction of antiseepage barrier.

2 cl, 1 dwg

FIELD: recovery of liquid radioactive waste.

SUBSTANCE: proposed method for recovering liquid radioactive waste of low level of activity from 137C radionuclides by extracting 137C radionuclide and alpha-ray nuclides involves introduction of magnetite slurry into solution being decontaminated, settling down of ferrocyanide magnetite particles selective to metal cesium extraction due to introduction of potassium ferrocyanide and soluble salt of respective metal into solution, and correction of solution pH to 9 by means of alkali. Sorbent is removed by settling it down followed by additional decontamination of cleared solution using magnetic separation method.

EFFECT: ability of decontaminating low-activity liquid radioactive waste from cesium radionuclides and alpha-ray nuclides.

1 cl

FIELD: nuclear engineering and technology, recovery of liquid radioactive wastes and their transfer to solid state.

SUBSTANCE: proposed method for immobilizing liquid radioactive wastes containing petroleum products involves introduction of natural sorbents into them. Used as sorbent is active water-repelling absorber. This absorber is used as filler and water, as tempering water.

EFFECT: ability of immobilizing liquid radioactive wastes containing petroleum products.

9 cl, 1 dwg

FIELD: recovering and degreasing liquid radioactive wastes.

SUBSTANCE: proposed method for decontaminating waste water from radioactive components incorporating in their composition dissolved and/or emulsified mineral oil, dissolved and solid particles of uranium radioactive components, and products of its decay by concentration of radioactive components and mineral oil. Prior to recovery waste water is acidified to pH = 2.5-3.0. Then iron salt based coagulant (III) and modified polyacrylamide based flocculant are introduced. After that waste water is neutralized with alkali to pH > 7 followed by centrifuging purified water and concentrate containing radioactive components and mineral oil. For final procedure concentrate is solidified and buried.

EFFECT: reduced energy requirement, enhanced speed of process.

1 cl, 5 tbl, 5 ex

FIELD: nuclear power engineering; recovery of liquid radioactive waste still bottoms at nuclear installations such as nuclear power stations.

SUBSTANCE: liquid radioactive still bottoms are recovered by passing them through cesium-selective inorganic sorbent for removing cesium-137 radionuclides from them. Used as cesium-selective inorganic sorbent are ferrocyanide sorbents. Then they are oxidized, and this is followed by separation of radioactive slime incorporating cobalt-60 hydroxide. For oxidation use is made of oxygenated oxidants free from ozone at temperature below boiling point of still bottoms and at pressure higher than that of saturated steam specified for this temperature.

EFFECT: facilitated procedure, reduced cost, enhanced safety, reduced recovery time due to reduced oxidation time.

3 cl, 1 dwg, 1 tbl

FIELD: immobilization of heterogeneous radioactive wastes.

SUBSTANCE: proposed method includes production of dehydrated radioactive sediment and filtrate on filtering centrifuge; heating of dehydrated radioactive sediment at 500 - 600 °C; crushing of products of heating into fragments measuring maximum 30 mm; case-hardening of crushed fragments with high-penetration cement solution which is, essentially, mixture of cement having specific surfaced area of minimum 8000 cm2/g and liquid phase at liquid phase-to-cement mass proportion of 0.6 - 1.4; for the final procedure mixture obtained is cooled down.

EFFECT: reduced amount of radioactive wastes, enhanced radiation safety, and reduced power requirement.

2 cl, 1 tbl, 2 ex

FIELD: treatment of heterogeneous liquid radioactive wastes.

SUBSTANCE: proposed method includes extraction of radium from radioactive oil slimes by means of hot water, acid or alkali solutions. Before doing so radioactive oil slime is subjected to recovery annealing with lack of hydrogen in atmosphere of incomplete combustion of carbon and hydrocarbons produced by using oil products. Recovery annealing temperature is maintained between 700 and 900 °C for 1 to 3 h. Annealed oil slime is treated with hot steam and once more with heat steam and sulfuric acid at concentration of the latter between 5 and 10% relative to mass of extracting solution.

EFFECT: enhanced quality of radioactive waste treatment.

4 cl, 1 dwg, 1 tbl, 1 ex

FIELD: recovery of liquid radioactive wastes.

SUBSTANCE: proposed method is used for localizing spent granular, powdered, or milled ion-exchange resins in Na- or H-form in dry or wet condition by including them in solid matrix. Matrix base is made of blast-furnace slag milled to fractions below 0.075 mm and tempered with sodium hydroxide solution of 100 - 150 g/l concentration.

EFFECT: enhanced degree of filling compound with wastes and extended range of its application.

1 cl, 1 dwg, 8 ex

FIELD: decontaminating natural water reservoirs from radionuclides.

SUBSTANCE: proposed method includes introduction of sorbent in contaminated water body. Used as sorbent is zeolite powder or man-produced substance, such as red slime or slime production waste. Mirabilite is used as precipitant and in addition water is decontaminated by using water-plant, such as reed and pondweed planted out in water reservoir in advance.

EFFECT: enhanced efficiency of water reservoir decontamination from radionuclides.

1 cl, 1 ex

FIELD: recovery of liquid radioactive wastes.

SUBSTANCE: proposed method for recovering alpha-active nitric acid solution containing trivalent iron includes pre-concentration of solution being recovered by its evaporation to produce regenerated nitric acid in still bottoms, whereupon still bottoms are neutralized to pH of 1 - 2 and trivalent iron is partially recovered by sodium sulfate until valence forms ratio Fe3+ : Fe2 = 2 : 1 is attained. This is followed by next neutralization with alkali to pH = 10 - 11. Magnetite sediment obtained after settling down is conveyed for curing. Then solution is decanted, clarified solution is magnetically separated and additionally cleaned.

EFFECT: reduced volume of secondary wastes, reduced consumption of chemical agents used for the purpose.

2 cl, 1 tbl, 1 ex

FIELD: radioactive waste processing by the burning method.

SUBSTANCE: the proposed furnace for radioactive waste burning has a case, within of which non less three burning chambers are coaxially located. The chambers have a general chamber for ash reburning. The general chamber is equipped with a fire grate. Each of burning chambers is autonomous, has the device for supply of fuel and oxidizer and is equipped with a fire grate and gate. The chamber for reburning the waste gases is coaxially located in the central part of the furnace. This chamber consists of external and internal cases, forming a labyrinth gas duct. The burning chambers are connected with the chamber for reburning the waste gases by means of gas-escape channels, having unequally-height and unequally-directional levels of location in each two neighboring burning chambers. A pressure-tight lock chamber of cylindrical shape is located over the burning chambers and chamber for waste gas reburning. The lock chamber is general for all burning chambers and is equipped with a cover, charging branch, pipe of exhaust ventilation, heat exchanger, transport system and control unit. The unit for control of the drives of transport system, fire grates, gates and strips is located on the lock chamber cover. The transport system consists of drive and container with a tray and limit switch. The container is fulfilled in the form of horizontally located cylinder. It is foreseen the circular motion of the cylinder. The drive of the transport system is connected with the container by means of an open gearing and is equipped with a gear, located on the output shaft. The output and input pipes for acceptance and unloading of wastes are located with good alignment one under other on the cylindrical surface of the container. The bushings are located on the side end surfaces of the container. The tray has possibility of rotation and has the shape of a bed, repeating the curvature of the internal surface of container case. Besides, the semi-axes are located on the semicircular side end surfaces of the container. These semi-axes together with the container bushings form a movable joint of the type of axis-bushing.

EFFECT: increased economical efficiency, processing efficiency, operation reliability and environment safety.

1 cl, 7 dwg

FIELD: methods of liquid radioactive wastes processing.

SUBSTANCE: the invention is pertaining to the field of liquid radioactive wastes processing. The invention presents a method of neutralization of the low-mineralized and medium-mineralized low-active liquid wastes in the field conditions, which includes the liquid wastes purification by mechanical filters and ultrafilters. The subsequent desalination is conducted by reverse-osmotic filters and an after-purification - by ion-exchange filters with a reactant treatment of the spent ion-exchange resins using potassium ferrocyanide and cobalt salts. Then the treated resin is used as a sorption prefilter, in which they use purification of the wastes before their feeding to the ion-exchange filter. The formed secondary A-wastes are fixed in the stable medium. Advantages of the invention consist is an improved purification efficiency and reduction of the secondary wastes volume.

EFFECT: the invention ensures improved purification efficiency and reduction of the secondary wastes volume.

3 ex

FIELD: nuclear engineering; methods of processing of radioactive effluent.

SUBSTANCE: the invention is pertaining to the field of nuclear engineering, in particular, to the methods of processing of radioactive effluent. The method of processing of the radioactive effluent containing radionuclides in the ionic and colloid forms and ballast components of the mineral and organic nature in the soluted and suspended states provides, that the organic components of the radioactive effluent are oxidized up to a gaseous state, and the mineral ionic components and radionuclides are transformed in a suspended state in the form of hydroxides of metals by feeding of the ozone waste. A stream of the oxygenated waste is separated for a thickened slurry and a liquid phase, using the selective sorbents conduct an afterpurification of the liquid phase from the radionuclides, which have remained in the ionic form. The produced slime and the spent sorbents are transformed into the solid form and sent for a long -term storage. Before treatment with ozone the stream of the radioactive effluent is purified from the suspended particles using its percolation through a mesh filtering material, and before an afterpurification of the liquid phase with the help of the selective sorbents conduct a membrane microstraining with separation from the liquid phase of radionuclides in the colloid form, which are sent back in the stream of the radioactive effluent after injection in it of ozone. The technical effect of the invention consist in an improved purification of the radioactive effluent from radionuclides.

EFFECT: the invention ensures an improved purification of the radioactive effluent from radionuclides.

1 dwg, 1 ex

FIELD: recovery of liquid radioactive wastes.

SUBSTANCE: proposed method for treatment of sulfuric ammonium radioactive solutions includes electrotype coagulation treatment involving passage of radioactive solutions through vibroliquefied iron-coke galvanic pair. Radioactive solution pH is corrected and radionuclide-containing deposit separated. In the process pH of radioactive solutions is corrected in two stages with deposit being separated after each stage. First-stage deposit is mixed up with montmorillonite clay and granules are molded. Then they are dried out and agglomerated to produce glass-ceramics wherein radionuclide-containing deposits are immobilized. Filtrate is treated with foam layer to blow off ammonia and then passed through natural ion-exchanger. Method for immobilizing radionuclide-containing deposit in glass-ceramics includes molding of granules of radionuclide-containing deposit mixed up with montmorillonite clay. Granules are molded in two stages. Core of granule of radionuclide-containing deposit mixed up with montmorillonite clay is produced during first stage and covered with shell of glass-ceramics based on homogeneous mixture of montmorillonite clay and quartz sand, during second stage, quartz sand content of mixture being 10 - 30 mass percent.

EFFECT: enhanced reliability of radioactive waste immobilization.

6 cl, 2 dwg, 1 tbl, 3 ex

FIELD: recovering and decontaminating liquid radioactive wastes.

SUBSTANCE: proposed method includes settling down of source radioactive waste flow to form above-the-sediment liquid and mud. Above-the-sediment liquid is clarified in mechanical filter and filtrate is formed in the process. Filtrate is separated by ultra-filtration to form concentrate which is mixed up with source flow of liquid radioactive wastes and permeate. The latter is separated into brine and dialyzate; the former is concentrated by way of electroosmosis producing radioactive concentrate flow and dilute flow mixed up with permeate flow; the latter is subjected to deep desalting to form decontaminated solution. In the process filtrate coming from mechanical filter is subjected to ion-selective sorption prior to ultrafiltration , then associating dopes are introduced therein. Ultrafiltration is made under forced turbulent conditions and deep desalting of dialyzate is conducted in two stages; first stage includes reverse osmosis and second one, electric deionization of decontaminated solution.

EFFECT: enhanced decontamination degree of solution and ability of recovering highly mineralized wastes.

1 cl, 1 dwg, 1 ex

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