Method for extraction of uranium from ores

FIELD: metallurgy.

SUBSTANCE: method involves leaching of uranium and iron using sulphuric acid solution and ferric iron contained in the ore as an oxidiser. After leaching is completed, uranium is extracted from the solution so that mother solution containing ferrous iron is obtained. Then, acidification of the mother solution is performed using sulphuric acid and recovery of ferric iron is performed by oxidation of ferrous iron so that a reusable solution is obtained, and recirculation of that solution for leaching of uranium is performed. Recovery of ferric iron is performed by action on the mother solution of high-voltage pulse electric discharges at high voltage pulse amplitude of not less than 10 kV and at pulse repetition cycle at the interval of 4001400 pulse/sec. At that, prior to action on mother solution with high-voltage pulse electric discharges, it is subject to dispersion.

EFFECT: reduction of power consumption and capital costs.

1 dwg, 2 tbl, 1 ex

 

The invention relates to hydrometallurgy uranium and can be used for acid percolation leaching of uranium from ore raw material for the regeneration of acidic solutions agitation leaching of uranium.

The method for extracting uranium from ore raw materials [patent RU No. 2393255, IPC SW 60/02, SW 3/08 (01.2006), publ. 27.06.2010. Bull. No. 18], which includes crushing, wet grinding of raw materials to receipt of the pulp, sulfuric acid leaching to produce pulp, and as a source of raw materials used ore containing brannerite, after wet grinding spend the thickening of the pulp, and after the acid leaching carry out the separation of the pulp, the upper drain after separation of direct countercurrent sorption of uranium, and the lower discharge containing brannerite fraction is acidified with sulfuric acid to 40-80 g/l with getting sour pulp and irradiate it with a stream of accelerated electrons with the power of the absorbed dose of 1.5 to 1.6 kGy/C for 4-8 min with subsequent leaching uranium and condensation of the resulting pulp with the formation of the upper discharge who served on the leaching of raw materials, and bottom drain, which is sent to the dump. In this case, the irradiation is subjected brannerite fraction in the form of acidic pulp with T:W<1:4, and irradiated slurry is leached under stirring at a temperature of 60-70C in t is the within 2-3 hours

The main disadvantages of this method include the high cost of the electron accelerator, providing the necessary power absorbed dose, and the need to ensure protection from radiation, which requires additional costs. Furthermore, the method is designed specifically for dissection resistant (refractory) brannerite ore raw material, which is provided by the irradiation of a suspension of solid particles of minerals in a liquid medium (slurry). In the proposed method, high-voltage pulsed discharges affect the mother liquor. The known method as considered similar only because in it, as in the implementation of the proposed method, the effect of electric current (an ordered movement of electric charges) directly on the material being processed.

A greater number of total essential features of the proposed invention has another similar method of uranium extraction from ores by means of heap or underground leaching [patent RU No. 2172792, IPC7SW 60/02, SW 3/08, publ. 27.08.2001], including the preparation of leach solutions containing sulfuric acid and nitrate ions, filtering them through the ore with the translation of hexavalent uranium, ferrous iron and other metals in production solutions, the extraction of uranium from the floor is rising uterine fluids and recycling of these solutions on the leaching of the ore. In the preparation of leach solutions of sulphuric and nitric acid is introduced into the part of the mother solutions, 0.05 to 0.15 from their original volume, taken from the conditions of establishment concentration of sulphuric acid equal to 100-250 g/l, and redox potential 750-850 mV. Then the resulting solution and the resulting nitrogen oxides in contact with another part of the uterine fluids equal to 0.25-0.35 of its original volume and is taken from the conditions for oxidation of Fe (II) Fe (III) with achievement of the redox potential 600-700 mV when the dispersion in a solution of oxygen or air. The resulting solution is mixed with the remaining part of the mother solutions with maintenance of the redox potential of the solution is equal to 420-500 mV, and before the introduction of sulfuric and nitric acids in the mother solutions produce the absorption of nitrogen oxides formed during the preparation of pls, by their contact with the source uterine solutions.

The main disadvantages of this method are the counterpart mandatory use of nitric acid, which leads to contamination of the solution of nitrate-ions, which reduces the sorption capacity of the ion-exchange resins for uranium, as well as the need for special equipment to capture the resulting toxic oxides of nitrogen.

Most blinkink proposed method on essential features and achieved a positive effect is selected for the prototype of the method of extraction of uranium from ores [patent RU No. 2326177, IPC SW 60/02, SW 3/08 (2006.01), publ. 10.06.2008. Bull. No. 16], including the leaching of uranium and iron sulfuric acid solution using as oxidant ferric iron contained in the ore, extraction of uranium from the solution to obtain a solution containing divalent iron, regeneration of divalent iron to trivalent oxidation with obtaining a working solution and its recycling to the leaching of the ore. The extraction of uranium from a solution of lead adsorption on the anion exchange resin obtained after adsorption solution containing divalent iron, before regeneration it divalent iron to trivalent acidified with sulfuric acid and the regeneration of lead exposure to a stream of accelerated electrons with the absorbed dose rate is 2.3-3.5 kGy/C for 1-6 minutes At this leaching methods are underground, heap or agitation leaching. Circulating the solution in heap or in-situ leaching, containing 0.5-5 g/l ferrous iron, before irradiation is acidified with sulfuric acid to a concentration of 5-10 g/l, and the working solution with agitation leaching, containing 5-15 g/l ferrous iron, before irradiation is acidified with sulfuric acid to a concentration of 10-20 g/L.

The main disadvantages of the method of the prototype the following:

- high energy consumption for processing solutions: 46,13 kWh 1 is 3solution when the degree of iron oxidation 86,6%;

- the need for biological protection;

significant capital costs due to the use of electron accelerator, the source of his power, and to provide protection from radiation.

The main technical result of the proposed solutions is that the energy consumption for processing solutions below 1.8 times (to 26.04 kWh 1 m3solution when the degree of iron oxidation 86,9%), And there is no need for biological protection and several times less capital expenditures; for example, the cost of the source of high voltage pulses applied in the proposed method, an order of magnitude less than the cost of the electron accelerator.

This technical result is achieved by the fact that in the proposed method to extract uranium from ore comprising leaching of uranium and iron sulfuric acid solution using as oxidant ferric iron contained in the ore, extracting uranium from a solution by obtaining a mother liquor containing ferrous iron, the acidification of the mother liquor with sulfuric acid, the regeneration of the ferric oxidation with obtaining a working solution and recycling of this solution in the leaching of uranium, the regeneration of ferric lead exposure in the mother liquor stand tname impulse discharges when the amplitude of the high-voltage pulses of at least 10 kV and pulse repetition rate in the range of 4004400 CPS, and before exposure to the mother liquor of high-voltage pulsed discharges it is subjected to dispersing.

A specific example of the proposed method (example based on factory testing method).

Figure 1 shows the installation for implementing the method, which consists of a series set of vessel source solution H2SO41, the vessel irrigation 2, column leaching 3, the receiving vessel 4, the sorption column 5, acidification vessel 6, block electrical discharge machining 7, the output of which is connected to the vessel irrigation 2, a source of high voltage pulses 8, electrically connected with the electric discharge block processing 7.

Crushed uranium ore, weighing 10 kg load in the column leaching 3. In the bowl of an initial solution H2SO41 prepared 8 liters of an aqueous solution of sulfuric acid at a rate of 5 g acid in 1 l of water and the solution is poured into a vessel irrigation 2. From it the sulfuric acid solution by gravity in a column leaching 3, in which there is a transition ions of uranium and iron from the ore into solution. This solution is collected in the receiving vessel 4. From the vessel 4 solution serves on the sorption in the sorption column 5, filled with ion exchange resins. In column 5 is the extraction of uranium from solution by ion exchange. Received the first in the sorption mother liquor, containing ions of Fe2+served in the acidification vessel 6, where concentrated sulfuric acid is exercised by the acidification of this solution to the initial concentration: 5 g H2SO4on 1 l of water. The acidified mother liquor from the vessel acidification 6 serves to block electrical discharge machining 7, in which this solution was dispersed and exposed to high voltage pulse discharges by filing in block 7 of the high voltage pulses from a source of pulses 8. Obtained working solution from a block of electro-discharge machining 7 served in the vessel irrigation 2. Thus the leaching of lead up until coming out in column 3 leaching solution, the uranium content is below 10 mg/L.

In tables 1 and 2 list the materials which substantiate the claimed digital mode parameters, which are included in the formula of the proposed invention. The results obtained at different amplitudes of voltage pulses, are shown in table 1, which shows that if the amplitude of the voltage pulses of less than 10 kV ignition discharge does not occur, so the amplitude must be at least 10 kV or higher. Table 2 presents experimental results of oxidation of iron at various frequencies-distance high-voltage pulses: 100 pulses/s up to 2000 pulses/s From these data it follows that an increase in the frequency of more than 1400 and the p/s is impractical as the degree of ocalenie (column 3) remains practically unchanged, and the energy consumption (columns 4 and 5) significantly increase. The lower frequency limit is chosen equal to 400 CPS, since the degree of oxidation at this frequency is, 53.1%, it is well known [Gromov BV "Introduction to chemical technology of uranium". Atomizdat. 1978, s]that for keeping up of process of oxidation of uranium (U4+) you must ensure that the ratio of the concentration of ions of Fe3+/Fe2+more units, that is, the oxidation must be more than 50%, which is not observed at frequencies less than 400 pulses/sec

The method of extraction of uranium from ores, including leaching of uranium and iron sulfuric acid solution using as oxidant ferric iron contained in the ore, extracting uranium from a solution by obtaining a mother liquor containing ferrous iron, the acidification of the mother liquor with sulfuric acid, the regeneration of the ferric oxidation of ferrous iron in the mother solution with the receipt of the circulating solution and recycling of this solution in the leaching of uranium, characterized in that the regeneration of ferric lead exposure in the mother liquor of high-voltage pulsed discharges when the amplitude of the pulse is at a high voltage of at least 10 kV and pulse repetition rate in the range of 4001400 imp./with, and before exposure to the mother liquor of high-voltage pulsed discharges it is subjected to the dispersion.



 

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FIELD: metallurgy.

SUBSTANCE: proposed process comprises crushing and grinding the ore, sulfuric acid leaching with addition of nitrogen acid as an oxidiser. Then, uranium is extracted and cleaned of impurities with the help of extractive agents mix to wash saturated extractive agent with the solution of sulfuric acid. After extraction, uranium is re-extracted to obtain uranium concentrate by means of 8-10%-solution of sodium carbonate. Uranium is deposited from re-extracted product by hydrogen peroxide with 50-100%-surplus from stoichiometry at equilibrium pH 3.6-4.2, mixing interval of 1- 1.5 h and sedimentation time of, at least, 1 h.

EFFECT: high quality finished uranium protoxide-oxide product.

4 tbl, 4 ex

FIELD: chemistry.

SUBSTANCE: invention relates to methods of extracting americium in form of americium dioxide from solutions. The invention can be used in the technology of extracting americium from production and radioactive wastes. The method involves concentrating nitric acid solution containing americium and impurities to americium content of not less than 100 mg/l by multi-step deposition of a precipitate containing americium, followed by dissolution thereof each time in a new portion of the starting solution. The precipitate containing americium is obtained from each portion of the solution by adding to 3.8-6.0 M nitric acid solution, which contains americium and impurities, ammonium hydroxide or an alkali metal hydroxide until achieving residual acidity of 0.1-0.2 M, oxalic acid to concentration of 10-50 g/l and adjusting acidity of the obtained reaction mixture to pH 0.6-2.3 if there are hydrolysable impurities in the starting solution and to pH 0.6-3.5 if not. The precipitate obtained by deposition from the americium-concentrated solution is then calcined and the calcined precipitate is then dissolved in nitric acid solution. Americium is then extracted from the obtained solution by a tributyl phosphate-based solid extractant, re-extracted, americium oxalate is deposited from the re-extract and then calcined to americium dioxide.

EFFECT: wider range of methods of extracting americium.

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FIELD: metallurgy.

SUBSTANCE: invention refers to complex processing method of carbon-silicic black-shale ores, which contain vanadium, uranium, molybdenum and rare-earth elements. The above method involves ore crushing to the particle size of not more than 0.2 mm and two leaching stages. Oxidation sulphuric-acid leaching is performed at atmospheric pressure. Autoclave oxidation sulphuric-acid leaching is performed at the temperature of 130-150C in presence of oxygen-containing gas and addition of a substance forming nitrogen oxide, as a catalyst of oxygen oxidation. Ion-exchange sorption of uranium, molybdenum, vanadium and rare-earth elements is performed from the obtained product solution.

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EFFECT: decrease of sulphuric acid content in desorbing solution and rich eluate and reduction of sulphuric acid consumption, decrease of desorbing solution flow and anion exchange resin ratio at de-sorption, increase of uranium content in rich eluate at decrease of rich eluate volume and decrease of uranium residual content by 1-2 levels in anion exchange resin after de-sorption.

1 tbl, 3 ex, 2 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to chemical engineering of inorganic substances and can be used to produce uranium tetrafluoride. The method of producing uranium tetrafluoride involves reduction and fluorination of triuranium octoxide with vapour from decomposition of ammonium fluoride taken in excess of 100-130 mol. % of the stoichiometric amount at temperature in the range of 260-700C.

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FIELD: process engineering.

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3 cl, 2 tbl

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2 tbl, 2 ex

FIELD: chemistry.

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2 tbl, 1 ex

FIELD: chemistry.

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1 tbl

FIELD: metallurgy.

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1 dwg, 7 tbl

FIELD: metallurgy.

SUBSTANCE: proposed process comprises crushing and grinding the ore, sulfuric acid leaching with addition of nitrogen acid as an oxidiser. Then, uranium is extracted and cleaned of impurities with the help of extractive agents mix to wash saturated extractive agent with the solution of sulfuric acid. After extraction, uranium is re-extracted to obtain uranium concentrate by means of 8-10%-solution of sodium carbonate. Uranium is deposited from re-extracted product by hydrogen peroxide with 50-100%-surplus from stoichiometry at equilibrium pH 3.6-4.2, mixing interval of 1- 1.5 h and sedimentation time of, at least, 1 h.

EFFECT: high quality finished uranium protoxide-oxide product.

4 tbl, 4 ex

FIELD: metallurgy.

SUBSTANCE: proposed method comprises ore pretreatment by crushing, classification and grading, biological degradation of ore silicate minerals by multiple ore interaction with silicate bacteria cultural medium without mixing with replacement of said cultural medium at pH, at least, 0.4. Then, metals are leached from biological degradation cakes by cultural solutions after extraction of silicon therefrom and additions of sulfuric acid to concentration of 50-450 g/l. After leaching, metals are extracted form cake leaching solution. Note here that cultural medium is replaced on reaching redox potential in solution of minus 250 mV. After biological degradation and before leaching, cakes are flushed with water.

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10 cl, 2 ex

FIELD: metallurgy.

SUBSTANCE: invention refers to complex processing method of carbon-silicic black-shale ores, which contain vanadium, uranium, molybdenum and rare-earth elements. The above method involves ore crushing to the particle size of not more than 0.2 mm and two leaching stages. Oxidation sulphuric-acid leaching is performed at atmospheric pressure. Autoclave oxidation sulphuric-acid leaching is performed at the temperature of 130-150C in presence of oxygen-containing gas and addition of a substance forming nitrogen oxide, as a catalyst of oxygen oxidation. Ion-exchange sorption of uranium, molybdenum, vanadium and rare-earth elements is performed from the obtained product solution.

EFFECT: increasing extraction degree of vanadium, uranium, molybdenum; improving the complexity of ore use owing to associated extraction of rare-earth elements.

18 cl, 1 dwg

FIELD: chemistry.

SUBSTANCE: invention relates to the technology of producing compounds of rare-earth elements during complex processing of apatites, particularly extraction of rare-earth elements from phosphogypsum. The method involves preparation of pulp from phosphogypsum and sorption of rare-earth elements on a sorbent. The pulp is prepared from ground phosphogypsum and sulphuric acid solution with pH=0.5-2.5 until achieving liquid:solid ratio of 4-7. Sorption is carried out directly from the phosphogypsum pulp on a sorbent with sulphuric acid functional groups for 5-7 hours with solid:sorbent ratio of 4-7.

EFFECT: high efficiency of the method owing to higher extraction of rare-earth elements without a filtration step.

6 tbl, 6 ex

FIELD: metallurgy.

SUBSTANCE: method includes leaching of ground raw materials in a solution of sulphuric acid with concentration of more than 2.0 g/l, containing ions of trivalent iron of more than 10-12 g/l, while mixing, at the temperature up to 100C, solid phase content to 60%, at least in two serially connected reservoirs. The pulp discharged from the last reservoir is separated into solid and liquid phases. At the same time the solid phase is returned for leaching into the first reservoir. Iron oxidation in the liquid phase is carried out with iron-oxidising bacteria adsorbed on a neutral carrier at the pH 1.4-2.2 and 90C with aeration by gas containing oxygen and carbonic acid. Then the liquid phase is returned after iron oxidation into leaching reservoirs, and metals are extracted from the produced phases. Besides, leaching is carried out with aeration by oxygen-containing gas. The pulp discharged from each reservoir is separated into solid and liquid phases. The solid phase is sent for leaching to the next reservoir, and the liquid phase is prepared prior to oxidation with bacteria. Duration of leaching is increased in each subsequent reservoir.

EFFECT: higher speed of bacterial iron oxidation and efficiency of sulphides dissolution, reduced dimensions of devices for bacterial oxidation of iron.

13 cl, 3 ex

FIELD: metallurgy.

SUBSTANCE: invention relates to the method for extraction of metals from metal-containing sulphide mineral raw materials. The method includes leaching with mixing of a sulphuric acid solution in presence of trivalent iron ions in at least two serially connected tubs, separation of leaching products into liquid and solid phases, iron oxidation in a liquid phase, return of the liquid phase after iron oxidation into leaching reservoirs, intermediate extraction of metals from liquid phases. At the same time the initial raw materials prior to leaching are exposed to preliminary acid treatment at PH=0.8-1.4, S:L=1:1. Leaching is carried out in two stages at the temperature of 75-95, PH=1.0-1.2 and S:L=1:(3-6), concentration of trivalent iron ions of 30-45 g/l at each stage with separation of leaching products after each stage into liquid and solid phases and iron oxidation in a liquid phase after each stage and with extraction of metals at each stage from liquid phases after iron oxidation. To the first stage raw materials exposed to preliminary acid treatment are sent, and to the second stage - a solid phase is sent, produced after separation of leaching products at the first stage. The liquid phase, which was produced after oxidation of iron at the second stage, is returned to the last leaching reservoir of the same stage.

EFFECT: higher extent of extraction of all precious metals into a solution and reduction of process duration by 1,2-1,5 times.

4 ex, 1 dwg

FIELD: hydrometallurgy of non-iron, rare and noble metals.

SUBSTANCE: invention relates to reprocessing of metal sulfide-containing ores, products and waste of ore concentrating and metallurgy industry. Method includes leaching in sulfuric acid solution with concentration of 1.8-35 g/dm3 at 0-1500C in presence of iron(III) ions with concentration more than 1 g/dm3 and iron regeneration using element compounds having built-in voltage when transition from highest valence to lowest one higher the same of iron. Compounds are added into solution when increasing iron(II) ion concentration. Method is useful in leaching by bawl, percolation, heap, and underground processes, as well as in metal recovering into solution, development of rare and noble metals, impregnated in metal sulfides. Invention affords the ability to reduce power requirement, increase effectiveness of equipment utilization, and decrease reagent consumption.

EFFECT: high degree sulfide decomposition with increased metal recovery and reduced leaching time.

8 cl, 3 ex

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