Method of processing natural-origin uranium-bearing ore

FIELD: metallurgy.

SUBSTANCE: proposed method comprises leaching the stock nitric acid solution to obtain suspension, introducing coprecipitator therein at 30-50°C and mixing. Then, clarified solution is separated from insoluble residue and directed for extraction. Said coprecipitator represents fresh solution of copolymer of acrylamide and chloride trimethyl ammonium ethyl acrylate of molecular weight of 3-15 millions with low charge density. Copolymer is introduced to concentration of 5.95-11.9 mg/l of insoluble residue. Prior to separation of clarified solution from insoluble residue settling is performed for 30-40 minutes.

EFFECT: lower processing costs.

3 cl, 1 dwg, 1 tbl

 

The invention relates to the processing of uranium-containing raw materials of natural origin, which includes impurities of various substances (mainly metals).

At dissolution (leaching) of uranium-containing materials, which comprises the admixture of various substances in solutions of nitric acid insoluble residue. In the process of extraction refining insoluble residues contribute to the formation of nerasseivayushchee emulsions (jellyfish) of the aqueous phase with the extractant - 30%TBP in a hydrocarbon diluent, which leads to disruption of the extraction process. Therefore, if the extraction production is focused on the processing of solutions that do not contain a solid phase, insoluble residues should be removed from solutions. It uses a variety of techniques, most often, sedimentation, filtration and/or centrifugation.

For example, in the method of chemical processing of natural uranium concentrate (NUC) [RF Patent №2398036, IPC SW 60/02, publ. 27.08.2010] source uranyl nitrate solution was prepared by dissolving NUC in nitric acid solution and separated from the resulting insoluble residue by decantation.

The method of processing of concentrated natural uranium oxides [RF Patent №2323883, IPC C01G 43/01, publ. 10.05.2008] includes leaching of uranium kontsentrirovano the th nitric acid at elevated temperature and separating the aqueous phase from the insoluble residue by filtration through a polyester cloth, PE-100 after settling for several hours or by centrifugation.

Closest to the claimed method is the processing of uranium raw materials, including leaching of uranium-containing raw material with a solution of nitric acid and separating the resulting slurry into solid and liquid components [Kozyrev, A.S., Ciceron YEAR, Ryabov A.S., Shamin, V., Mikhailova N.A., Skuratov MV intensification of the processes of separation of highly concentrated solutions of uranyl and fine suspended solids. Bulletin of the Tomsk Polytechnic University. - 2007. - 311 so. No. 3. - Page 16-19]. In this way in the nitric acid solution of uranyl nitrate, obtained by leaching (dissolution) of the concentrate in the form U3O8(the impurities are 12% by weight of the sample) with the concentration of uranium 300-450 g/l of nitric acid 0.7 to 3.0 mol/l, enter the primary coagulant cationic type FLOQULAT™ FL 45 in the amount of 100-200 mg/l for the destabilization of the colloidal system. Then, the suspension is injected secondary cationic flocculant FO 4140 PWG in the amount of 5-10 mg/l for the formation of macrolophus. The process is carried out at a temperature of 30-50°C. After injection of coagulant and flocculant insoluble residue (mass which does not exceed 0.6% by weight of the sample) was separated from solution by filtration, to obtain a transparent solution of uranyl nitrate, suitable for the extraction process. This method is chosen for the prototype.

The disadvantages of this method to the convicts who are stated in the process of separating the insoluble residue from the suspension time-consuming because it requires the use of several types of coosawatee and additional costs for instrumentation process.

Object of the invention is the intensification of the process of separation obtained in the leaching of uranium feedstock suspensions clarified water and the insoluble residue, namely, an increase in the speed of lightening suspension and reducing the amount of insoluble residue.

The set task is solved by the fact that in the method for processing of uranium-containing raw materials of natural origin, including leaching solution of nitric acid to obtain a suspension, an introduction to the suspension of shoesadidas at a temperature of 30-50°C, stirring, separating the clarified solution from the insoluble residue and the extraction solution, the suspension is injected freshly prepared solution of a copolymer of acrylamide and trimethylammoniumchloride chloride with a molecular mass of from 3 to 15 million, with a low charge density. Copolymer of acrylamide and trimethylammoniumchloride chloride is introduced into the suspension to its concentration 5,95 is 11.9 mg/g of insoluble residue. The Department clarified solution from the insoluble residue is carried out after sludge within 30-40 minutes.

Figure 1 shows graphs of the time full oswell is of the slurry from the concentration of coosawatee, used in the claimed method and the prototype.

In order to intensify the process of separation obtained in the leaching of uranium feedstock suspensions clarified water and the insoluble residue studies have been conducted on the selection of coosawatee suitable for separating the insoluble residue from the suspensions obtained by the leaching of uranium-bearing materials, and optimal conditions of separation.

As source material used peroxide uranium UO4·2H2O (piroxicamnova acid (H2UO5·H2O). The chemical composition of this raw material is characterized by a significant content of the following impurities: iron, aluminum, calcium, sulfur, molybdenum (number of impurities 30% by weight of the sample).

Suspension of uranyl nitrate was obtained by dissolution of the feedstock in the solution of nitric acid. The dissolution process was carried out at a temperature of 60-95°C with constant stirring system with a mechanical stirrer at 1000 rpm the resulting suspension had a characteristic brown-orange color of ferric hydroxide on the background of yellow-green highly concentrated solution of uranyl nitrate. The uranium concentration in the aqueous phase of the resulting suspension was in the range of 200-450 g/l, the concentration of free nitric acid of 0.1-1 mol/l Insoluble residue was 1,53% of mA the son of a sample.

The resulting suspension was divided into three parts: one control, the rest is added freshly prepared solutions:

1. In the first series of experiments the polymer complex (high charge density) on the basis of diallyldimethylammonium chloride in the form of vinylpyridine (activation of the polymer shown by formula 1), then the cationic flocculant (low charge density), which is a chlorinated polymer of an organic Quaternary ammonium bases, in the amount of 5-10 mg/l In the experiments of this series are similar to the prototype used a solution of coagulant VPK-402 and flocculant FO 4140 PWG, possessing the above characteristics.

where R is a hydrocarbon skeleton and an inactive functional group

2. In the second series of experiments the solution of a copolymer of acrylamide and trimethylammoniumchloride chloride [(C3H5NO)x-(C8H15NO2Cl)y], where x=57000 11000..., y=57000 11000...with a molecular mass of from 3 to 15 million, with a low charge density (activation is represented by formula 2). In the experiments in this series were used flocculant solution FO 4190, possessing the above characteristics.

To determine the speed of achieving a complete clarification of the suspension was measured optical density of solutions. For full clarification of the suspension took the time what I when the optical density of the solution became constant.

Experiments were performed as follows. Immediately after the dissolution of the original uranium-containing raw materials each piece resulting suspension was mixed and divided into 13 equal portions of 50 ml each.

From the first portions of each part of the resulting suspension immediately after separation (i.e., without exposure of suspension) were selected from the top 25 ml of suspension, the sample was mixed and measured the optical density of the sample fotoelektrokalorimetry. Then at set intervals of time(5, 10, 15, 20, 30, 40, 60, 90, 120, 150, 180 minutes in a day) conducted similar measurements with the other portions.

During the experiments it was noted that in the control part of the suspension is approximately 1/3 of the volume of the insoluble residue during the day, defended and represented very mobile, easy vspuchivanie sediment, 2/3 of the volume of the insoluble residue formed by solution sedimentation-sustainable system that 3-4 days Svetlanas 25-30%.

It was also noted that with the introduction of coosawatee all insoluble residue in the system almost immediately becomes flaky. The combined use of coagulant VPK-402 and flocculant FO 4140 reduces the time of the full clarification to 2.5 hours. The introduction of the flocculant FO 4190 allows you to reduce the time of the full clarification of the solution to 30 minutes.

The graphs presented in figure 1 show that with the introduction of the flocculant FO 4190 (claimed invention) the speed of lightening suspension is higher than with the introduction of the coagulant VPK-402 (prototype)at any concentration of shoesadidas and despite the fact that in the method according to the prototype to improve process efficiency and reduce the dosage of coagulant to the minimum number required for destabilization of the suspension system further added flocculant FO 4140.

During experiments it was found that the smallest time clarification of the suspension corresponds to the concentration in the system flocculant FO 4190 equal 95-110 mg/l, which is 5,95 is 11.9 mg/g of insoluble residue.

Obtaining a minimum amount of insoluble residue leads to an increase in yield of purified solution and contributes to the intensification of the process of separation obtained in the leaching of uranium feedstock suspensions clarified water and the insoluble residue. In the process of conducting experiments have been marked changes in volume of the thick part of the suspension depending on shoesadidas and exposure time. The measurement results are shown in table 1.

Table 1
The volume change novellen the second part of the suspension depending on shoesadidas
The concentration of nitric acid, mol/lThe volume of the thick part of the suspension, % vol.
10 min30 min
Without the use of coosawateeConcentration VPK - 402 in the system of 100 mg/l and FO 4140 PWG 5 mg/lThe concentration FO 4190 PWG in the system of 100mg/lWithout the use of coosawateeConcentration VPK - 402 in the system of 100 mg/l and FO 4140 PWG 5 mg/lThe concentration FO 4190 PWG in the system of 100 mg/l
0,1997250943527
0,2986845903426
0,4976230922714
0,8 945929842918
1945928862816

The data presented in table 1 allow us to draw the following conclusions. The introduction of a copolymer of acrylamide and trimethylammoniumchloride chloride allows you to receive less than the introduction of polymer complex on the basis of diallyldimethylammonium chloride and optionally chlorinated polymeric organic Quaternary ammonium bases, the volume is not clarified part of the suspension. And for achieving this result requires nitric acid of lower concentration.

After separation of the suspension into clarified water and the insoluble residue, the insoluble residue was separated from the solution by filtration. The measurement of the velocities of the filter showed that the combined use of coagulant VPK-402 and flocculant FO 4140 allows you to increase the filtration rate from 20 to 75 ml/min, and added to a suspension of flocculant FO 4190 increases the speed to 110 ml/min

After separation of the suspension, the resulting solution was sent to extract the Y. During the process of education nerasseivayushchee emulsions were observed.

The experiments prove that the use as shoesadidas separating suspensions solution (low charge density) [- (C3H5NO)x-(C8H15NO2Cl)y], where x=57000 11000..., y=57000 11000...with a molecular mass of from 3 to 15 million resulting from the copolymerization of acrylamide and trimethylammoniumchloride chloride, reduces the amount of time the bleaching solutions and ensures the formation of a smaller amount.

Implementation of the proposed method of separation of insoluble residues from suspensions of uranyl nitrate will significantly reduce the time of settling and filtration, which in turn will have a positive impact on cost of capital and, consequently, will reduce the cost of processing the entire circuit as a whole.

1. Method for processing of uranium-containing raw materials of natural origin, comprising leaching the material with a solution of nitric acid to obtain a suspension, an introduction to the suspension of shoesadidas at a temperature of 30-50°C, stirring, separating the clarified solution from the insoluble residue and the direction of the solution on the extraction, characterized in that the suspension is as shoesadidas impose a freshly prepared solution of copolymer acrylamide of trimethylammoniumchloride chloride with a molecular mass of from 3 to 15 million and with a low charge density.

2. The method according to claim 1, characterized in that the copolymer of acrylamide and trimethylammoniumchloride chloride is introduced into the suspension to its concentration 5,95 is 11.9 mg/g of insoluble residue.

3. The method according to claim 1, characterized in that before separating the clarified solution from the insoluble residue conduct advocacy for 30-40 minutes



 

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