Method of processing silicon-containing chemical concentrate of natural uranium

FIELD: chemistry.

SUBSTANCE: method involves leaching a concentrate with aqueous nitric acid solution at high temperature to obtain a pulp which consists of a solid phase and an aqueous phase, filtering off the aqueous phase in form of uranyl nitrate solution, extraction refining uranium using tributyl phosphate in a hydrocarbon diluent. The filtered uranyl nitrate solution, which contains uranium in concentration of 200-400 g/l, dissolved silicon in concentration of 1.0-3.2 g/l and nitric acid in concentration of 1-2 mol/l, is held until stabilisation of viscosity before being fed for extraction.

EFFECT: preventing escape of the aqueous phase with the uranium extract, which improves efficiency of the extraction stage, lowers content of impurities in the uranium extract and enables to obtain a product which meets ASTM C 788-03 requirements.

1 dwg, 1 tbl

 

The invention relates to methods for processing chemical concentrates, natural uranium (NUC) and can be used in the technology of extraction processing NUC with a high content of silicon in order to obtain nuclear-friendly materials, suitable for the production of uranium hexafluoride for enrichment.

It is known that the threshold concentration of silicon in acidic solutions, which do not form the polymer compound is 0.1 g/l With increase in the content of silicon in acidic solution of silicic acid into a gel, stabilizing the extraction of the emulsion and reduce the purification of uranium from ballast impurities (dujshebaev BO, Alimbaev MS, Saykiev AGRICULTURAL and other study the behavior of silicon in the process of preparing uranium-containing raw materials. Purification of uranium-bearing solutions from silicon. Report on the 3rd International conference "Actual problems of uranium industry". - Almaty, Republic Of Kazakhstan, 2004).

There are several ways, warning of the negative impact gel of silicic acid on the extraction refining of uranium.

The known method, for preventing the gel of silicic acid by the introduction of coagulants - polymers in cationic form (Iler R. the Chemistry of silica. - M.: Mir, 1982, V.1, S).

However, this leads to the formation of precipitation, which slow the race is ivanie extraction of emulsions in the process of refining uranium.

The negative impact of silica gel can be avoided if the extraction is to apply a solution of uranyl nitrate, in which melirovanie silicic acid has only just begun. For example, known is a method of processing NUC (RF Patent No. 2444576, IPC SW 60/02, publ. 10.03.2012). This method of processing NUC with a high silicon content includes dissolving the concentrate in a solution of nitric acid and extraction of uranyl nitrate from fresh pulp, which is obtained flow interaction at a temperature of 20-65°C pre-prepared flow of a suspension concentrate in the water and flow solution of nitric acid at a ratio of expenditure flows, providing the concentration of nitric acid in the pulp 25-120 g/l, while from the beginning of the leaching prior to the extraction does not exceed 10 minutes.

The disadvantage of this method is that its implementation requires a special reactor for continuous dissolution of the concentrate and uniform distribution nerastvorim residues in the pulp supplied to the extraction.

If NUC uneven or contaminated mechanical inclusions, to prevent driving communications and valves of tanks refinery sludge coming from the dissolution of the NUC before extraction must be separated by filtration. zwesten method of chemical processing of natural uranium concentrate (Patent RF №2447168, IPC SW 60/02, publ. 10.04.2012). The method adopted for the prototype. This method process the concentrate with a high content of silicon. The method includes the following steps: leaching of the concentrate with an aqueous solution of nitric acid; separation by filtration of the aqueous phase in the form of a nitrate solution of uranium from solid phase (insoluble residue); the extraction of uranium from nitric acid solution of tributyl phosphate in a hydrocarbon diluent, washing of the extract and reextraction uranium. This leaching lead by adding nitric acid and water in an amount to provide a receipt in the aqueous phase of the pulp nitric acid solution containing the dissolved silicon concentration of 2.5-3.7 g/l Solid phase consisting of insoluble residues concentrate is separated by filtration from the solution containing the dissolved silicon, uranium concentrations 170-250 g/l and nitric acid in a concentration of 80-120 g/HP Filtering is carried out not later than 24 hours from the end of leaching, mainly no later than 5 hours after leaching.

This method allows you along with insoluble residues be removed from the solution part of the silica gel. However, this method does not protect the extraction refining of uranium from the negative influence of silica gel in the case, if the technical possibilities do not allow usamedsonline to carry out the extraction of the filtered solution of uranyl nitrate.

If the filtered original solution of uranyl nitrate to apply for extraction immediately, but after exposure (for example, after the accumulation of the initial solution in collection for several days), the conditions of extraction refining of uranium nitrate worse: on the extraction of uranyl nitrate reduced speed separation of emulsions (in this case, to increase the duration of the process of emulsion breaking degrade the performance of the extraction redistribution or accumulation occurs at the phase boundary interface units (jellyfish), the transfer of which to extract reduces the purification of uranium from ballast substances. The reason for this is melirovanie silicic acid, which at the time of filtering did not zaselyalas and moved to a filtered solution of uranyl nitrate.

The objective of the invention is to prevent performance degradation extraction process and reduction purification of uranium from ballast impurities in the negative impact of gels of silicic acid on the extraction refining of uranyl nitrate in the processing of aged solutions obtained from dissolution NUC with a high silicon content.

The set task is solved by the fact that in the method of processing silicon-containing chemical concentrate of natural uranium with a high content of credit the Deposit, includes leaching the concentrate with an aqueous solution of nitric acid at elevated temperature to obtain slurry consisting of solid and aqueous phases, the separation by filtration of the aqueous phase in the form of a nitric acid solution of uranyl nitrate from the solid phase extraction refining of uranium using tributyl phosphate in a hydrocarbon diluent, filtered nitric acid solution of uranyl nitrate containing uranium at a concentration of 200-400 g/l, dissolved silicon concentrations of 1.0-3.2 g/l and nitric acid in concentrations of 1-2 mol/l, prior to the extraction of the stand to stabilize the viscosity of the solution. The method is as follows.

Dissolved several parties NUC which contains silicon in a solution of nitric acid at a temperature of 80-90°C. the resulting slurry was cooled to room temperature and no later than one day after the dissolution was separated by filtration. The filtered solution was kept for several days, periodically measuring the viscosity of solutions and speed separation extraction of the emulsion and the amount of jellyfish in the test, simulating the extraction process.

Fig.1 shows the results of viscosity measurements and testing of the filtered solution composition [U]=to 216.2 g/l, [HNO3]=2.2 mol/l, [Si]=1.8 g/l

The figure shows that in the process of aging hotfil trojanova solution of uranyl nitrate is its viscosity increases during the first eight days relatively slowly from 1,307 to 1,693 mm 2/s, and then during the day there is a sharp increase up to 2.684 mm2/sec. And from then on the tenth day of the viscosity remains constant, equal 2,952 mm2/s

Also the figure shows that the increase in the viscosity of the filtered solution is accompanied by a change of speed of separation of the extraction of the emulsion with the filtered aqueous solution and change the size of the jellyfish. In the first few days the speed of separation of the emulsion is reduced, and the height of jellyfish increases, and after eight days of exposure, the orientation process is followed: speed separation of the emulsion began to grow, and the height of jellyfish to decrease, until its complete disappearance.

Therefore, melirovanie silicic acid in the filtered solution, accompanied by an increase in the viscosity of the filtered solution, leads to the acceleration of emulsion breaking and reducing the size of jellyfish during extraction.

Also was measured viscosity and tests the filtered solution obtained by dissolving NUC with different silicon content. The results of determining the continuing increase in the viscosity of solutions with different silicon content are shown in table 1.

Table 1
the duration of growth of the viscosity of solutions with different silicon content depending on the concentration of nitric acid and uranium
no experienceThe composition of the initial solutionThe duration of the growth solution viscosity, the day
[Si], g/l[HNO3], mol/l[U], g/l
10,91,020328
30,92,020717
20,91,039811
40,92,04039
51,81,019920
61,82,021610
7 1,81,04067
81,82,04095
93,21,02057
103,22,02095
113,21,04012
123,22,04031

The table shows that the cessation of growth of the viscosity of the filtered solutions of uranyl nitrate depends on the content of the uranium concentrations of silicon and nitric acid: with increasing concentrations of uranium (ceteris paribus), with increasing concentrations of dissolved silicon and an increase in the concentration of nitric acid, the observed decrease in the duration of growth of viscosity solutions. In this case, as in the previous experience is, stopping the increase of viscosity solutions was also accompanied by acceleration of emulsion breaking and reducing the size of jellyfish during extraction.

Processing silicon solutions NUC, filtered from the suspension by filtration, under production conditions on extraction stage countercurrent extraction columns using as extractant 30%TBP in the hydrocarbon diluent showed that the extract before extraction solutions of uranyl nitrate (with composition similar to the composition of the above solutions) to stabilize the viscosity of the solutions was provided by the reduction of interfacial structures in the phase boundary extraction columns, the lower latency of the aqueous phase in a continuous organic phase and the termination of entrainment of the aqueous phase to extract uranium. It is possible to increase the extraction performance of the cascade, to reduce the content of impurities in reextract uranium and to obtain a product that meets the requirements of ASTM With 788-03.

Thus, the extract filtered solution to stabilize its viscosity helps to protect the extraction refining of uranyl nitrate from the negative impact of gels of silicic acid.

A method of processing silicon-containing chemical concentrate of natural uranium, including the leaching of the concentrate with an aqueous solution of nitric sour the s at elevated temperatures with obtaining pulp, consisting of solid and aqueous phases, the separation by filtration of the aqueous phase in the form of a nitric acid solution of uranyl nitrate from the solid phase, applying the solution on the extraction refining of uranium using tributyl phosphate in a hydrocarbon diluent, characterized in that the filtered nitric acid solution of uranyl nitrate containing uranium at a concentration of 200-400 g/l, dissolved silicon concentrations of 1.0-3.2 g/l and nitric acid in concentrations of 1-2 mol/l, prior to the extraction refining stand to stabilize the viscosity of the solution.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: invention relates to method of uranium extraction from mother liquors. Method includes obtaining resin, modified by aminophosphonic groups, and obtaining mother liquor, which contains from 25 to 278 g/l of sulphate and uranium. After that, mother liquor is passed through resin, modified by aminophosphonic groups, in acid form to separate uranium from mother liquor. Then, elution of uranium from resin is realised.

EFFECT: possibility of sorption extraction of uranium from solutions, which contain high concentrations of sulfate.

7 cl, 1 tbl, 3 ex

FIELD: metallurgy.

SUBSTANCE: proposed process comprises leaching of uranium by nitric acid and separation of water phase from undissolved precipitate. Then, undissolved precipitate is mixed with fluorine-bearing agent, dissolution of produced charge and/or charge as a suspension in nitric acid solution. Produced solution is returned to production process for extraction of uranium. Nitric acid concentration in solution makes at least 2 mol/l. Dilution is carried out at fluorine-ion concentration at, at least, 15 g/l. Dilution is performed at 60-100°C.

EFFECT: decreased losses of uranium, minimised wastes.

4 cl, 1 dwg, 1 tbl

FIELD: chemistry.

SUBSTANCE: method involves dissolving wastes in concentrated nitric acid, oxalate precipitation from the solution, drying and calcining the americium oxalate to americium dioxide. The solution obtained by dissolving wastes with high concentration of impurity cations, one of which is ferric iron, is mixed with a reducing agent for reducing ferric iron to ferrous iron. After reduction, the solution with acidity by nitric acid of 1-2.5 mol/l is taken for extraction of americium with a solid extractant based on different-radical phosphine oxide, followed by washing and re-extraction of americium. Oxalate precipitation is carried out from the re-extract with americium concentration of not less than 3 g/l and nitric acid concentration of not less than 3 mol/l, said precipitation being carried out in two steps: adding an oxalate ion to the americium-containing solution in weight ratio to americium of (2-7):1 and then adding water to the separated precipitate in volume ratio to the precipitate of (3-8):1 and the oxalate ion in weight ratio to americium of (1-4):1. The obtained reaction mixture is boiled and taken for separation of americium oxalate from the solution.

EFFECT: high output of the product and degree of purity thereof.

4 cl

FIELD: metallurgy.

SUBSTANCE: metallic uranium obtaining method involves electrolysis of uranium dioxide in the melt of lithium and potassium chlorides in an electrolysis unit with a graphite anode and a metal cathode and release of metallic uranium on the cathode and carbon dioxide on the anode. First, mixtures of uranium dioxide and carbon are prepared in molar ratio of 6:1 and 1:1 by crushing the corresponding powders; the obtained powders are briquetted into pellets. To the anode space of the electrolysis unit, which is formed with a vessel with porous walls, which is arranged in a ceramic melting pot, there loaded are pellets obtained from mixture of uranium dioxide and carbon, and melt of lithium and potassium chlorides. To the cathode space of the electrolysis unit, which is formed with the vessel walls with porous walls and the ceramic melting pot, there loaded is melt of lithium and potassium chlorides and uranium tetrachloride in the quantity of 5-15 wt % of lithium and potassium chlorides. Electrolysis is performed at the electrolyte temperature of 500-600°C, cathode density of current of 0.5-1.5 A/cm2, anode density of current of 0.05-1.5 A/cm2, in argon atmosphere with periodic loading to anode space of pellets of mixture of uranium dioxide and carbon.

EFFECT: current yield of metallic uranium is 80-90% of theoretical.

1 ex

FIELD: chemistry.

SUBSTANCE: method involves dissolving a chemical concentrate of natural uranium in nitric acid solution, extracting and re-extracting uranium. The dissolved concentrate contains 1.2-3.7 wt % iron to uranium, 1.4-4.0 wt % sulphur to uranuim and 0-0.7 wt % phosphorus to uranium in nitric acid solution. Nitric acid and water are taken in an amount which provides the following concentration in the solution fed for extraction: uranium 450-480 g/l, iron (III) ions 0.1-0.3 mol/l, sulphate ions 0.2-0.6 mol/l, phosphate ions 0-0.10 mol/l, and free nitric acid 0.8-2.4 mol/l, and saturation of extractant with uranium during extraction is maintained in accordance with the ratio: Y ≤90.691-34.316·[SO4]+7.611·([Fe]-[PO4])+5.887·[HNO3]-9.921·[SO4]·[HNO3]+19.841·[SO4]2+7.481·([Fe]-[PO4])·[HNO3]-64.728·([Fe]-[PO4])·[SO4]+92.701·[SO4]·[HNO3]·([Fe]-[PO4])-185.402·[SO4]2·([Fe]-[PO4]), where Y is saturation of the extractant with uranium, %, and concentration in the solution fed for extraction, mol/l: [SO4] - sulphate ions, [PO4] - phosphate ions, [HNO3] - nitric acid, [Fe] - iron (III) ions.

EFFECT: obtaining raffinates with low uranium content.

1 tbl

FIELD: metallurgy.

SUBSTANCE: method includes sorption of rich components from production solutions by ion-exchange material counterflow under controlled pH of environment and oxidation-reduction potential Eh. Sorption is performed by ion-exchange materials in stages from production solutions containing uranium, molybdenum, vanadium and rare earth elements. At the first stage uranium and molybdenum are extracted by anion-exchange material sorption. At the second stage vanadium is extracted by anion-exchange material sorption with hydrogen dioxide available at Eh of 750-800 mV, pH of 1.8-2.0 and temperature of 60°C, at that vanadium sorption is performed till complete destruction of hydrogen dioxide and till Eh is below 400 mV. Then barren solutions are transferred to cationite at pH of 2.0-2.5 and Eh of 300-350 mV for extraction of rare earth elements.

EFFECT: sorption concentration and selective separation of uranium and molybdenum from vanadium, and vanadium from rare earth elements, and rare earth elements from iron and aluminium, intensification of sorption process, reduction of flow diagram and possibility of environmentally sound oxidants use.

1 dwg, 4 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: processing method of black-shale ores includes crushing, counterflow two-stage leaching by sulfuric acid solution upon heating, separation of pulps formed after leaching at both stages by filtration. Then valuable soluble materials are washed from deposit at the second stage with strengthened and washing solutions being produced, marketable filtrate is clarified at the first stage for its further processing. Ore is crushed till the size of 0.2 mm, leaching at the first stage is performed by cycling acid solution with vanadium under atmospheric pressure, temperature of 65-95°C during 2-3 hours, till residual content of free sulphuric acid is equal to 5-15 g/l. Leaching at the second stage is performed at sulphuric acid rate of 9-12% from the quantity of initial hard material under pressure of 10-15 atm and temperature of 140-160°C during 2-3 hours. Cake filtered after the first stage is unpulped by part of strengthened solution which content is specified within 35-45% of total quantity.

EFFECT: high-efficiency extraction of rich components, possibility of pulps separation by filtration after leaching with high properties thus reducing costs for separation processes.

3 cl, 1 dwg, 1 tbl

FIELD: metallurgy.

SUBSTANCE: processing method of black-shale ores with rare metals extracting includes leaching of ore by sulphuric acid solution with dilution of rare metals. Leaching is performed in autoclave by sulphuric acid solution consisting of free and combined sulphuric acid with ratio of H2SO4(free):H2SO4(comb)=2:1, and containing 25-45 g/l of iron sulphate, 70-90 g/l of aluminium sulphate and 0.5 g/l of nitric acid. At that the process is performed under pressure in autoclave equal to 10-15 atm with mixing at temperature of 140-160°C in concentration range of general H2SO4(gen) equal to 350-450 g/l under pulp density S: L=1:0.7-0.9, preferably 1:0.8, under constant oxidation-reduction potential Eh in the system equal to 350-450 mV during 2-3 hours till residual concentration of free H2SO4(free) is within 45-75 g/l.

EFFECT: increasing break-down of ore and extraction of rare metals: vanadium, uranium, molybdenum and rare-earth elements, reducing consumption of acid and improving efficiency of autoclave volume usage.

1 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to the technology of processing chemical concentrates of natural uranium, involving leaching (dissolving) the concentrate and extracting uranium using tributyl phosphate in a hydrocarbon diluent. The method involves dissolving the concentrate using aqueous nitric acid solution, feeding the obtained aqueous uranyl nitrate solution to the extract outputting step of a stepped extraction unit and extracting uranium with tributyl phosphate in a hydrocarbon diluent. Extraction is carried out by counterflow interaction of the aqueous and organic phases. Concentrate containing thorium impurities in ratio of 1 wt % to uranium is used. During extraction at the extract outputting step, the step for saturating the extractant with uranium is kept at least 87% of the maximum saturation of the extractant with uranium, and a portion of the aqueous phase, which is not more than 60 vol. % of the uranyl nitrate solution fed to the extract outputting step, after one of the extraction steps is removed from the extraction process and fed for dissolving the uranium concentrate.

EFFECT: high extraction of uranium and nitric acid from the raffinate.

1 tbl

FIELD: metallurgy.

SUBSTANCE: method involves use of an unbalanced solution consisting of a solution from the washing process of anionite from the acid and filtrate from the filter press, and their removal from the process together with a mother solution from deposition of natural uranium concentrate through an additional saturation operation together with a marketable reclaimed product. For that purpose, the plant includes a local solution recirculation circuit in the form of a collector for solutions of unbalanced and mother concentrate from deposition, which is connected to pipelines of the above solutions and equipped with solution supply pipelines attaching the collector through a gravity tank to an additional saturation column from the marketable reclaimed product and to a solution return pipeline attaching the gravity tank to the solution collector of the local solution recirculation circuit.

EFFECT: reduction of nitrate ions emissions; reduction of prime cost of end product and compliance with strict environmental requirements.

2 cl, 2 dwg, 1 tbl, 2 ex

FIELD: metallurgy.

SUBSTANCE: proposed process comprises leaching of uranium by nitric acid and separation of water phase from undissolved precipitate. Then, undissolved precipitate is mixed with fluorine-bearing agent, dissolution of produced charge and/or charge as a suspension in nitric acid solution. Produced solution is returned to production process for extraction of uranium. Nitric acid concentration in solution makes at least 2 mol/l. Dilution is carried out at fluorine-ion concentration at, at least, 15 g/l. Dilution is performed at 60-100°C.

EFFECT: decreased losses of uranium, minimised wastes.

4 cl, 1 dwg, 1 tbl

FIELD: chemistry.

SUBSTANCE: method involves dissolving a chemical concentrate of natural uranium in nitric acid solution, extracting and re-extracting uranium. The dissolved concentrate contains 1.2-3.7 wt % iron to uranium, 1.4-4.0 wt % sulphur to uranuim and 0-0.7 wt % phosphorus to uranium in nitric acid solution. Nitric acid and water are taken in an amount which provides the following concentration in the solution fed for extraction: uranium 450-480 g/l, iron (III) ions 0.1-0.3 mol/l, sulphate ions 0.2-0.6 mol/l, phosphate ions 0-0.10 mol/l, and free nitric acid 0.8-2.4 mol/l, and saturation of extractant with uranium during extraction is maintained in accordance with the ratio: Y ≤90.691-34.316·[SO4]+7.611·([Fe]-[PO4])+5.887·[HNO3]-9.921·[SO4]·[HNO3]+19.841·[SO4]2+7.481·([Fe]-[PO4])·[HNO3]-64.728·([Fe]-[PO4])·[SO4]+92.701·[SO4]·[HNO3]·([Fe]-[PO4])-185.402·[SO4]2·([Fe]-[PO4]), where Y is saturation of the extractant with uranium, %, and concentration in the solution fed for extraction, mol/l: [SO4] - sulphate ions, [PO4] - phosphate ions, [HNO3] - nitric acid, [Fe] - iron (III) ions.

EFFECT: obtaining raffinates with low uranium content.

1 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to technology of rare metals, in particular to hydrometallurgy of zirconium and hafnium. Method of zirconium and hafnium separation includes obtaining zirconium and hafnium hydroxides at temperature, not higher than 30-35°C, dehydration of obtained zirconium and hafnium hydroxides, their dissolution in nitric acid and following extraction of zirconium by tributylphosphate extraction from obtained solution in backflow, water phase is removed from cell in the middle of cascade, nitric acid is added to it, and obtained solution is introduced into the following stage downstream water phase movement.

EFFECT: invention ensures increase of zirconium separation, increase of cascade work stability and reduction of nitric acid consumption.

4 cl, 5 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: invention relates to the technology of processing chemical concentrates of natural uranium, involving leaching (dissolving) the concentrate and extracting uranium using tributyl phosphate in a hydrocarbon diluent. The method involves dissolving the concentrate using aqueous nitric acid solution, feeding the obtained aqueous uranyl nitrate solution to the extract outputting step of a stepped extraction unit and extracting uranium with tributyl phosphate in a hydrocarbon diluent. Extraction is carried out by counterflow interaction of the aqueous and organic phases. Concentrate containing thorium impurities in ratio of 1 wt % to uranium is used. During extraction at the extract outputting step, the step for saturating the extractant with uranium is kept at least 87% of the maximum saturation of the extractant with uranium, and a portion of the aqueous phase, which is not more than 60 vol. % of the uranyl nitrate solution fed to the extract outputting step, after one of the extraction steps is removed from the extraction process and fed for dissolving the uranium concentrate.

EFFECT: high extraction of uranium and nitric acid from the raffinate.

1 tbl

FIELD: chemistry.

SUBSTANCE: method involves leaching the concentrate with aqueous nitric acid solution at high temperature to obtain a pulp consisting a solid and an aqueous phase. The aqueous phase is then separated by filtration from the solid phase in form of uranium nitrate solution. Uranium is then extracted from the nitrate solution using tributyl phosphate in a hydrocarbon solvent. The extract is washed and uranium is re-extracted. Leaching is carried out by adding nitric acid and water in an amount which enables to obtain a nitrate solution in the aqueous phase of the pulp, said nitrate solution containing dissolved silicon in concentration of 2.5-3.7 g/l. The solid phase, which consists of insoluble concentrate residues, is separated by filtration from the solution which contains dissolved silicon, uranium in concentration of 170-250 g/l and nitric acid in concentration of 80-120 g/l. Filtration is carried out not more than 24 hours after leaching, preferably not more than 5 hours after leaching.

EFFECT: obtaining clean nuclear materials, suitable for producing uranium hexafluoride for enrichment.

2 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: method involves leaching in order to dissolve uranium when the concentrate reacts with nitric acid solution to obtain pulp from the concentrate. Uranium is then extracted from the pulp using tributyl phosphate in a hydrocarbon solvent. The extract is washed and uranium is re-extracted. Extraction is carried out from freshly prepared pulp which is obtained through direct-flow reaction at temperature 20-65°C of a stream of a suspension of the concentrate in water which is prepared beforehand and a stream of nitric acid solution with flow rate ratio which ensures nitric acid concentration in the pulp of 25-120 g/l. The period from the beginning of leaching to the beginning of extraction is not more than 10 minutes.

EFFECT: protection of extraction from formation of non-demixing emulsions, providing given purity of uranium from ballast impurities and obtaining raffinates which can be removed into underground collector sand layers.

2 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: processing method of nitric-acid solution of regenerated uranium involves uranium (VI) extraction with tributyl phosphate in organic diluter; flushing of extract with nitric-acid solution and re-extraction of uranium. At that, removal of technetium from uranium is performed by shifting technetium (VII) to non-extracted quadrivalent state in flushing zone of extraction cascade with the use of flushing solution containing 0.1-0.2 mol/l of carbohydrazide and 0.05-0.15 mol/l of nitric acid. Extract is flushed at the ratio of flows of organic and water phases, which is equal to 10-15. Method can be implemented in two versions. As per the first version, used flushing solution is supplied to feed stage of extraction cascade and technetium is removed to raffinate. As per the second version, used flushing solution is a separate flow from which uranium is extracted by contact with flow of fresh extractant; organic phase is connected to initial uranium extract prior to supply to flushing zone, and technetium is removed to separate product the volume of which is 5 times less than the raffinate volume.

EFFECT: increasing separation efficiency of uranium and technetium.

9 cl, 2 dwg

FIELD: metallurgy.

SUBSTANCE: conversion method of non-ferrous metal salt involves counterflow extraction of metal from solution of its converted salt with the use as cation-exchange extractant in salt form of solution of organophosphorus acid in inert diluter and re-extraction of non-ferrous metal with converting acid so that re-extract containing converted salt of non-ferrous metal is obtained. As non-ferrous metal there used is cobalt or nickel; extraction is performed from solution of converted salt of cobalt or nickel at concentration of cobalt or nickel in solution 65-80 g/l and pH 4-7 with the use as cation-exchange extractant of 20-50% solution of organophosphorus acid in sodium, potassium or ammonia form. Re-extraction is performed with 0.5-2.0 M solution of converting acid. Number of non-ferrous metals to which the proposed method is applied can also include copper and zinc.

EFFECT: increasing conversion degree at minimum content of impurities and enlarging the range of obtained salts of non-ferrous metals.

5 cl, 8 ex

FIELD: metallurgy.

SUBSTANCE: invention refers to procedures for processing chemical concentrate of natural uranium. The procedure consists in dissolving natural uranium in solution of nitric acid, in directing solution to uranium extraction with tri-butyl-phosphate and hydrocarbon thinner, in washing extract with re-extract and in uranium re-extracting. There is dissolved chemical concentrate of natural uranium with increased content of phosphorus and sulphur. Uranium is extracted from solutions with increased concentration of phosphorus and sulphur and with concentration of nitric acid 30÷80 g/l to 60÷75% saturation of extractant with uranium. Also this level of extractant saturation with uranium in the said range in % is maintained not exceeding value equal to (0.3×[HNO3]+51), where [HNO3] is concentration of nitric acid in solution directed to extraction, in g/l.

EFFECT: purification of uranium at minimal uranium losses with raffinate.

2 tbl

FIELD: metallurgy.

SUBSTANCE: method includes leaching of uranium concentrate by solution of nitric acid, uranium extraction by tributyl phosphate in hydrocarbon solvent. Uranium extraction is implemented up to 85-92% saturation of extragent by uranium. Then it is implemented washing of extract by part of evapoarted reextract, containing 450-500 g/l of uranium, which is implemented in the mode of ultimate (up to 119-120 g/l of uranium) of saturation of extragent by uranium. After washing it is implemented uranium re-extraction. Washing solution, received after washing of uranium extraction is combined with uranium solution from concentrates leaching and after correction by content of nitric acid and uranium mixed solution is directed to extraction. Extract washing is implemented at correlation of flows O:B=(15-20):1. Content of nitric acid in uranium solutions directed to extraction is 0.5-0.8 mole/l.

EFFECT: increasing of uranium purification efficiency from molybdenum.

4 cl, 4 tbl, 1 ex

FIELD: nanotechnology.

SUBSTANCE: invention relates to the technology of production of gold nanoparticles. The method of production of gold nanoparticles from the raw material containing iron and non-ferrous metals comprises preparation of the chlorazotic acid solution of gold using chlorazotic acid. Then floatation extraction of gold precursors is carried out with cationic surfactants from the solution, separation and evaporation of the organic phase to concentrate the gold precursors. Then the concentrate reduction is carried out to obtain dispersion of gold nanoparticles. At that the starting material is first treated with hydrochloric acid to form the insoluble precipitate. Production of chlorazotic acid solution is carried out by dissolving in chlorazotic acid solution of insoluble precipitate. Before floatation extraction of precursors the nitric acid is removed from chlorazotic acid solution with methyl or ethyl alcohol or hydrochloric acid.

EFFECT: improvement of efficiency of the method of production of nanoparticles, namely the increase in the number of gold nanoparticles obtained or its hybrids with noble metals.

3 ex

Up!