Method of uranium recovery from ores

FIELD: metallurgy.

SUBSTANCE: said utility invention relates to hydrometallurgical methods of crude ore processing and may be used for sulphuric-acid agitation, heap, and underground leaching of uranium during uranium recovery from ores. The method involves uranium and iron leaching with sulphuric acid solution using ferric iron contained in the ore as the oxidiser; after that, uranium is recovered from the solution to prepare a solution containing ferrous iron, the ferrous iron is regenerated to ferric iron by oxidising to prepare bypass solution, and it is recirculated to the ore leaching. The uranium recovery from the solution is performed by sorption on an anion-exchange substance; after sorption, the solution containing ferric iron is acidified with sulphuric acid before the ferric iron regeneration to ferrous iron in the solution, and regeneration is performed by irradiating it with an accelerated electron flow at an absorbed dose rate of 2.3-3.5kGy/s during 1- 6 minutes.

EFFECT: increase in cost effectiveness, efficiency, and environmental safety of process.

4 cl, 3 dwg, 3 tbl, 2 ex

 

The invention relates to the hydrometallurgical processing methods of ore and can be used, in particular, sulphuric acid campaign (AB), heap (KB) and underground (PV) leaching of uranium.

Known methods sulphuric acid leaching using as oxidant uranium sulfate ferric /see, for example, Ring R.J. Hydrometallurgia, 1980, 6, 89-101/. Production practice shows that leaching is the most costly redistribution in the overall scheme of processing of uranium ores, therefore, the efficiency of this operation determines the cost of the final product.

According to modern ideas about the electrochemical mechanism of dissolution of uranium dioxide (uraninite, pitchblende and so on) under the action of ferric sulfate to leaching medium was the most effective, all of the iron must be present in the solution in the trivalent form. In the real solution, the presence of other ions in the first ion Fe2+causes a decrease of the speed of the process as a result of competitive adsorption of these ions on the active centers of the surface of the uranium mineral. With a large number of ions of Fe2+in the solution is required to maintain an excess of ions of Fe3+to ensure a satisfactory reaction rate.

On practically oxidation of the bivalent iron ions in sulfuric acid solutions of various known methods, in particular:

- the use of strong oxidizing agents (pyrolusite, chlorates, nitric acid and the like),

molecular oxygen or oxygen:

at elevated temperature and pressure in an autoclave,

at atmospheric pressure, sometimes with catalytic additives (nitrous acid, and others).

All these methods either due to the cost of chemical reagents, which leads to contamination of the solution by impurities (ions), or require the introduction of additional operations, or lack the necessary performance, which ultimately leads to a significant increase in the cost of redistribution.

The known method sulphuric acid agitation leaching of uranium using as oxidant iron compounds contained in the ore. The method consists in splitting the flow of the original slurry into two streams. In the first pre-leached iron with sulfuric acid to neutralize the excess acid pulp of the second stream and oxidize iron oxygen at atmospheric pressure, then again serves acid (if required with the addition of manganese dioxide or ferric). These operations are carried out in a battery of several Pachuca at a temperature of 60-80°for more than 12 h /Larin VK, Litvinenko VG, Sheludchenko VG improving the technology guy is remetalling processing of uranium ores. Mining magazine. 1999, No. 12, 59/. However, due to slow oxidation of iron by oxygen in an acidic environment, this method does not have high efficiency and requires significant energy (compressed air, steam) costs.

The known method sulphuric acid leaching of uranium from ores using ferric iron as an oxidant, including its chemical regeneration. This method involves 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 the final solutions, the extraction of uranium with obtaining uterine fluids and recycling of these solutions on the leaching of ore.

Intensification of the process of leaching of uranium from ores methods KB or PV is achieved through the use of circulating solutions in which ions Fe (II) oxidized to Fe (III), and the latter is already fulfill the role of a direct oxidant of uranium (IV) to uranium (VI). The oxidation of Fe (II) Fe (III) is carried out mainly by oxygen, Bartiromo through the recirculating solution, when the catalytic participation of nitrous acid and nitrogen oxides resulting from the decomposition of nitric acid, which is the source of nitrogen-containing reagent /patent RF №2172792 C1, application 2000106961/02, AVL. 21.03.00, publ. bull. No. 24, 27.08.01. - prototype/.

The disadvantages of this method are:

- the use of several reagents, in particular nitric acid for the formation of an oxidant and as a result, contamination of the production of solutions of nitrate-ions, which reduces the sorption capacity of anion exchange resins for uranium

- the release of toxic nitrogen oxides formed during the preparation of pls, and the need for them to capture with the use of special equipment (vessels with dispersant),

- use as a reagent technical oxygen or less effective oxygen for oxidation of the formed nitrogen oxides and iron (II)

- lack of ecological purity due to the inability to complete the capture of toxic oxides of nitrogen,

the difficulty in the practical implementation and accuracy of maintenance of the set of process parameters.

The technical result of the proposed method is to improve the economy, efficiency and environmental friendliness of the process of leaching of uranium from ores with sulphuric acid is used as an oxidant iron ore.

This result is achieved in that in the method of extraction of uranium from ores underground methods or heap and agitation leaching with sulfuric acid using as the oxidant Fe (III), contained in the ore, including the leaching of uranium and iron, the extraction of uranium sorption on the resin, the receipt of the circulating solution, the regeneration of the oxidation of Fe2+to Fe3+in this solution and its recycling to the leaching of the ore, and circulating a solution containing divalent iron, after doreplace sulfuric acid is irradiated with a flux of high-energy electrons when the absorbed dose rate is 2.3-3.5 kGy/C for 1-6 minutes Working solution heap or underground leaching, containing 0.5-5 g/l Fe2+before irradiation is acidified with sulfuric acid, going to the leaching of uranium to a concentration of 5-10 g/L. Clarified working solution agitation leaching obtained by thickening or hydrocycloning discharged slurry containing 5-15 g/l Fe2+before irradiation acidified part of sulphuric acid required for leaching the ore to a concentration of 10-20 g/L.

We developed a "reagentless" radiation-chemical technology of regeneration of the oxidant. The transfer of ions of bivalent iron to trivalent form without the participation of chemicals and forced heating is achieved by irradiation of the solution with a stream of accelerated electrons. It is established that short-term (a few minutes) exposure model sulfate solutions of ferric sulfate which allows almost completely oxidize ferrous ions to the trivalent state in a wide range (1-10 g/l) concentrations of iron and sulfuric acid. Developed radiation-chemical technology "reagentless" regeneration effective oxidant for use in the processes KB and PV, and agitation leaching of uranium with sulfuric acid.

Radiation-chemical technology is currently one of the most progressive. The production of linear accelerators industrial type developed by the enterprise Agency for AE of the Russian Federation (St. Petersburg) and at the plant of the Institute of nuclear physics. Of nuclear physics, SB RAS in Novosibirsk. These units are widely used for work around the clock in environmental technologies for industrial wastewater treatment, effluent of textile production and cattle-breeding complexes, drinking water, toxic waste, etc. /XI International conference on application of accelerators in industry and medicine (ICAA'05)/ St Petersburg, October 2005/.

Thus, the efficiency, effectiveness and environmental friendliness of the process sulfuric acid extraction of uranium from ores methods of propaganda, heap and underground leaching using as oxidant ferric ions is achieved by circulation of the circulating solution after sorption of uranium extraction and regeneration of the oxidizing agent by the irradiation of these solutions stream of accelerated electrons and return the attachment regenerated oxidant in the leaching of uranium.

Example 1. The degree of oxidation of ferrous iron on the duration of exposure. Main technological parameters of the process at a given mode of exposure is the concentration of iron ions and sulfuric acid. The influence of these parameters on the degree of oxidation of the bivalent iron ions was studied in the range of concentrations of Fe2+1-5 and acid 2-5 g/l, i.e. with respect to the conditions of the processes of ROS and KB uranium from ores ( see table 1).

The degree of oxidation of ferrous iron was calculated as the change in the concentration of bivalent iron ions in irradiated and unirradiated solutions:

(Feneall-Feregion)/Feneall·100[%].

The sulfuric acid concentration was determined by potentiometric titration, the concentration of iron trigonometricas (sulfosalicylic acid) before and after irradiation.

Researched solutions in open plastic jars with a capacity of 100 ml were placed on a rotating table (10 rpm) of the working chamber, which are regulated relative to the beam so that the beam hit the center of the irradiated sample.

The experiments were carried out under the following energy parameters:

- kinetic energy 7 MeV,

- the average current of 25 μa,

the current density - 32 µa/cm2.

The power of the absorbed dose was determined from the known is tion ratio

Dm=ηIE/m

where η - coefficient taking into account the proportion of absorbed in the sample beam of electrons to the water solution of 0.95, I is the average current of accelerated electrons, E is the kinetic energy of the electrons, m is the mass of the solution.

Solutions after irradiation remained transparent. Exposure to acidified (2.4 g/l, pH 1,6) sulfate solution ferrous iron concentration ˜0.8 g/l when the absorbed dose rate of 3.46 kGy/s in less than a minute provides a high degree of oxidation (˜87%). The almost complete oxidation of iron is achieved in just 1.5-3 min (see table 1). By increasing the concentration of ions of bivalent iron to 5.2 g/l high degree of iron oxidation (at 92%) is achieved for 6 min at lower absorbed dose rate to 2.3 kGy/s, i.e. almost in half.

Example 2. The degree of oxidation of ferrous iron concentration of iron ions and sulfuric acid in the irradiated solution.

The influence of these parameters on the degree of oxidation of the bivalent iron ions in the irradiated solutions was studied at concentrations of Fe2+1-11 and acid in the range of 2-16 g/l (see table 2).

As can be seen from table 2, the degree of iron oxidation strongly depends on the initial concentration of ferrous iron and sulfuric acid in the solution. But when the concentration of iron (II) 1 g/l degree ocil the deposits reaches 100%, regardless of the acidity of a solution.

With increasing concentration of ferrous iron in the original solution from 1 to ˜11 g/l (see table 2) found a significant effect of the concentration of sulphuric acid on the oxidation of ferrous iron in the exposure.

With the increase of iron concentration in the source solution to 2.5 g/l (see No. 5-8 table 2) and the acid concentration of 10-15 g/l oxidation of ferrous iron is 100%. At lower acid concentrations (up to 2-5 g/l) oxidation state of iron is somewhat reduced (up to 80-88 %).

Table 1

The degree of oxidation of the bivalent iron ions on the duration of irradiation (τ) at different absorbed dose rate (DM)
No. op. PCTτ, minDM, kGy/sThe characteristic solutionThe oxidation state of Fe %
Concentration, g/lO-RR, mV
Fe3+Fe2+H2SO4
Ex.0-0,440,822,43900
10,8of 3.461,15 1,948086,6
21,51,210,051,950093,9
33,01,27N.D*)2,0500100
46,01,272,5590100
Ex.0-0,905,20the 5.73650
51,02,302,63,54,044542,9
62,03,52,7the 3.846048,6
73,04,22,02,947561,5
84,0the 4.71,42,948073,1
96,0the 5.70,42,550092,0
*) the concentration is not detected.

To obtain the same result by increasing the iron concentration to the ˜5 g/l concentration sour the s should be above 10 g/L. When the iron concentration in the initial solution, more than 10 g/l and high acid concentration (˜16 g/l) oxidation is ˜54 %. The increased duration of exposure to 6 min at a dose rate of 3.5 kGy/s increases the degree of iron oxidation up to 70-80%.

Table 2

The degree of oxidation of iron (II) concentration of iron and sulfuric acid when absorbed dose rate of 2.3 kGy/s and duration of exposure 3 min
No. op. PCTThe original solutionThe irradiated solutionThe oxidation state of Fe %
Concentration, g/lO-RR, mVConcentration, g/lO-RR, mV
Fe3+Fe2+H2SO4Fe3+Fe2+H2SO4
10,21,02,53601,2the concentration is2,3600100
25,1365the 4.7660
310,6 3609,1675
414,736513,5675
53,52,52,23455,50,5pH 1.846080,0
65,3350the 5.70,3

the concentration is
1,847088,0
710,03556,07,3500100
815,035511,4510
90,9of 5.42,23553,7*2,4pH 2.043551,9
105,2the 5.74,22,03,447061,5
115,310,75,11,17,249079,2
125,315,85,80,412,251592,4
132,010,3 2,43705,56,9pH 2.042533,0
141,710,65,03755,56,93,743034,9
151,610,69,83756,56,06,344543,4
161,610,815,83757,55,09,146053,7
17**1,610,69,83759,03,25,547069,8
18**1,610,815,837510,22,28,649079,6
* - fell precipitate of iron hydroxide (III)

** the exposure time of 6 min with DM=a 3.5 kGy/s

The oxidation of bivalent iron ions is accompanied by a corresponding increase in the magnitude of About-EAP, reaching values 500-675 mV at 100%oxidation. At pH˜2 due to the lack of free acid in the solution p is oshodi termogidrodinamicheskoe decomposition minor part of the ions of ferric sulfate and education Zola hydroxide. Results the dependence of the oxidation rate (N, %) iron (II) concentration of sulfuric acid (g/l) and iron (II) is illustrated by figure 1, where the concentration of iron (II) in the original solution: the series 1-1 g/l, the range of 2-2,5 g/l, range 3-5,3 g/l, range 4-10,6 g/l

These dependencies allow us to determine the completeness of the oxidation of bivalent iron ions in relation to current solutions process sulphuric acid leaching of uranium.

In table 3 are examples of compositions of the solutions obtained after leaching of uranium and iron in various ways (productive solution and working solution after regeneration of the oxidant by acidification with sulfuric acid and irradiation stream of accelerated electrons.

Table 3
Method of leachingProductive solutionWorking solution
concentration, g/lO-RR, mVconcentration, g/lO-RR, mV
UH2SO4Fe+3Fe+2UH2SO4Fe+3Fe+2
Underground0,05 1,00,20,83600,0150,90,1600
Heap0,45,00,95,33550,02105,11,1500
Agitation0,8101,610,83750,022010,22,2500

The maximum degree of extraction of uranium in solution at this pH occurs when the value Of-EAP solution at the level of 500-600 mV, i.e. when the minimum concentration of ions of bivalent iron.

Based on the data available process flow diagram of the extraction of uranium from ore with sulfuric acid at underground, heap (figure 2) and agitation (figure 3) leaching.

Productive solutions after KB or ISL uranium sulfuric acid using as oxidant iron contained in the ore, proceed on the sorption of uranium. The mother liquor, in which the iron is predominantly in the reduced form, i.e. in the form of divalent ions is working and after the addition of acid required for the leaching of uranium, and the regeneration of the oxidant returns what is in the leaching operation. The operation of regeneration, i.e. radiation-chemical oxidation of the bivalent iron ions to the trivalent state radiolysis products, is carried out by irradiation of the solution with a stream of high-energy electrons produced by the linear accelerator.

When the agitation leaching scheme (figure 3) is characterized by the fact that on the sorption of uranium enters the pulp, and the allocation of working solution (top discharge) is carried out by condensation or gidrotsiklonirovaniya (or filtering) the acidic pulp. The thickened slurry of (floor drain) goes to dump. In this case, the regeneration is carried out at pH<2, which in operation serves a small portion of the acid from entering the leaching of uranium.

1. 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, 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, characterized in that 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 same is ESA to trivalent acidified with sulfuric acid and the regeneration of lead exposure to a stream of accelerated electrons with the power absorbed dose of 2.3 to 3.5 kGy/C for 1-6 minutes

2. The method according to claim 1 characterized in that the leaching methods are underground, heap or agitation leaching.

3. The method according to claim 2, characterized in that the circulating solution at a compact or underground leaching, containing 0.5-5 g/l ferrous iron, before irradiation is acidified with sulfuric acid to a concentration of 5-10 g/L.

4. The method according to claim 2, characterized in that the circulating 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.



 

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20 cl, 2 dwg, 9 tbl, 13 ex

FIELD: non-ferrous metallurgy; methods of extraction of vanadium out of the highly concentrated lime slag.

SUBSTANCE: the invention is pertaining to the field of non-ferrous metallurgy, in particular, to vanadium metallurgy, namely to the method of extraction of vanadium out of the highly concentrated lime slag providing for the wet milling of the highly concentrated lime slag with production of the pulp, treatment of the slag pulp with the sulfuric acid and its oxidizing burning, the sulfuric-acidic leaching of the burning product with the subsequent settling of vanadium from solution by hydrolysis. The technical result of the invention is the increased output of the extracted vanadium as the commercial product, and also improvement of the production process indices at reprocessing of the highly concentrated lime slag. For gaining the technical result the milled slag pulp is treated with the concentrated sulfuric acid taken in the amount of 30-35 % to the mass of the slag. The oxidizing burning is conducted at the temperature of 700-950°С. The product of the burning is subjected to leaching in the weak-acid solution of the sulfuric acid and conduct vanadium settling from the produced solution.

EFFECT: the invention ensures the increased output of the extracted vanadium as the commercial product, the improved production process indices at reprocessing of the highly concentrated lime slag.

1 tbl, 8 ex

FIELD: hydrometallurgy, chemical technology.

SUBSTANCE: invention relates to the leaching reaction of manganese from manganese-oxide ores. Solution used for leaching manganese-oxide ores contains the following components, wt.-%: sulfuric acid, 19.0-20.0; ethylene glycol, 30.0-80.0, and water, the balance. Using the proposed solution that is stable in strongly acid media and at high temperatures (200°C) provides enhancing the selective rate of dissolving manganese oxides from depleted manganese-oxide ores. Invention provides the complete dissolving manganese oxides based on surface reduction of manganese dioxide.

EFFECT: improved and valuable chemical properties of solution.

1 dwg, 2 ex

FIELD: rare-earth element technology.

SUBSTANCE: invention relates to technology of recovering rare-earth elements from phosphogypsum obtained from processing of apatite concentrate into mineral fertilizers. Phosphogypsum is treated with 22-30% sulfuric acid solution at liquids-to-solids ratio 1.8-2.2 to recover rare-earth elements and sodium into solution. Insoluble precipitate is separated and degree of oversaturation of solution regarding rare-earth elements is increased by means of providing sodium concentration 0.4-1.2 g/L, after which crystallization of rare-earth element concentrate is allowed to proceed and concentrate is then separated from mother liquor. Treatment duration is 20-30 min to prevent spontaneous crystallization of rare-earth element concentrate in solution before insoluble precipitate is separated. Content of sodium in solution is controlled by adding a sodium salt thereto, preferably sodium sulfate or sodium carbonate. Degree of recovery of rare-earth elements from phosphogypsum into concentrate achieves 71.4%.

EFFECT: increased degree of rare-earth element recovery and simplified procedure due to eliminated operation of dilution of recycle sulfuric acid solutions and shortened sulfuric acid treatment duration by a factor of 2-3.

2 cl, 1 tbl, 3 ex

FIELD: rare metal technology.

SUBSTANCE: method comprises leaching of initial material in sulfuric acid aqueous solution to produce solution and solid precipitate, said leaching conducted in presence of sulfate of metal having higher positive oxidation potential than that of aluminum. Solution obtained is treated with complexing ampholite with benzyliminodiacetate groups and thus recovered gallium is then concentrated.

EFFECT: increased degree of gallium recovery into solution and reduced consumption of sulfuric acid.

4 cl, 3 tbl, 3 ex

FIELD: metallurgy.

SUBSTANCE: invention relates to method for enrichment of slurries from nickel electrolysis and other products containing platinum metals, gold and silver as well as to method for reprocessing of products obtained by processing of sulfide copper-nickel ores. Claimed method includes slurry autoclave oxidative leaching followed by flotation. Leaching is carried out at 108-110°C and oxygen partial pressure of 0.4-1.0 MPa.

EFFECT: concentrate with low content of non-ferrous metals.

6 ex

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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