Method for the selective extraction of uranium from ores
(57) Abstract:The invention relates to the hydrometallurgical processing of orangutango raw materials, in particular to a method for the selective extraction of uranium from ores by leaching and sorption. The inventive ore is subjected to crushing, wet grinding with obtaining pulp and is carried out at a pH of 4.2-2.2 in the one or more devices leaching and forth without performing neutralization at pH 4.6-2.0 leaching process combined with countercurrent sorption of uranium, maintaining the pH in the head in the course of the slurry apparatus ionite processing pH 4.6 to 2.6, preferably 4.0 to 3.6 and at a pH in the tail apparatus ionite processing of 3.4 to 2.0, preferably of 3.2 and 2.4. The temperature of the acid and ionite processing pulp support 30-70oC, preferably 40-60oC. as an oxidant use of manganese compounds, desorption of uranium from a busy ion exchanger exercise sulfuric-nitric acid solutions. 3 C. p. F.-ly, 1 Il., 5 table. The invention relates to the hydrometallurgical processing of uraniastrasse raw materials and can be used in acid campaign showdown ores for extraction of uranium by ion exchangers.A method of refining uranopilite the NCA, neutralization with limestone slurry with subsequent separate sorption and desorption of uranium and molybdenum (Technical progress in the nuclear industry. ser. New industrial technology, vol. 5, S. 25, 1994).The disadvantages of this method are considerable consumption of sulfuric acid 120-140 kg/soHigh and also the neutralizing agent (20-25 kg/t CaO) used to adjust (raise) the pH before the sorption of uranium.There is also known a method of extracting uranium from ore comprising grinding and wet grinding of raw materials, acid leaching in the presence of MnO2or NaClO3neutralizing the pulp NH4OH to a pH of 1.8, the sorption and desorption of uranium (Staroverov D. I. and other Hydrometallurgical processing orangutango raw materials. M Atomizdat, 1979, S. 111-112).The disadvantages of this method relates primarily to the low selectivity of sorption of the significant content of the ion exchanger impurities at low saturation resins useful component and, as a consequence, high concentrations of uranium in the drawdown pulp.Currently in the acid processing methods involved silicate ore with higher compared to previously mined raw material concentrations inevitably leads to an increase in consumption of sulfuric acid in their leaching. A significant part of the H2SO4spent on the opening of the iron-bearing minerals, the intensity and completeness of the flow of this process depends on many factors, the main of which is the pH of the processing of the pulp. In certain conditions it is possible to provide a minimal degree of translation in the solution of iron and, consequently, reduce the consumption of sulphuric acid.Under other equal conditions for the saturation of the ion exchanger uranium is influenced by the pH of the process of ion exchange and the impurity concentration in the liquid phase of the pulp (Fe3+SO24-and others).In the known method leaching of uranium is carried out at low pH (0,8-1,5), this inevitably translates into solution a large amount of iron, there is an increased consumption of acid, high concentration of sulfate ions. Subsequent neutralization of the alkaline suspension of an alkaline agent to adjust the pH before sorption does not significantly reduce the content in the solution of sulfate ions. An increase in pH to 2.0-2.5 and above leads to the precipitation of iron from the liquid phase into the solid and the coprecipitation of uranium, and with increasing pH, the intensity of these processes is greatly increased.Thus, in the considered technology in the high pH an increase in its losses. In the first case, there is also a high concentration on the sorbent iron, follow-up which requires additional material costs.The technical result of the invention is to increase the selectivity of the process of acid-ionite extraction of uranium, i.e., to ensure complete saturation of the sorbent uranium and the minimum concentration therein of impurities, reduction of the consumption of sulfuric acid and in General, reducing the unit cost of extracting uranium from ore processing.This technical result is achieved that the opening of the useful component and removing the ion exchanger moved countercurrent to the pulp, leading to the conditions under which the iron-containing species is translated into a solution to a minor extent, and uranium in sufficient detail goes into the liquid phase and focuses on the sorbent. In the proposed method, the acid leaching of the ore pulp is carried out in the presence of an oxidant at a pH of 4.2 to 2.2, and countercurrent sorption of uranium at pH 4.6 to 2.0, the output is saturated resin from the pulp is carried out at pH 4.6 to 2.6, preferably of 4.0 and 3.6, the desorption of uranium from a busy ion exchanger (regeneration of the sorbent) are sernistokislogo solutions, the input (supply) aregenerative and sorption is carried out in apparatus of ionite processing. Ion-exchange extraction of uranium on the resin reduces the concentration of the useful component in the liquid phase and leads to additional translation useful component from the ore into solution. The operation of the leaching of raw materials should be carried out in two or three devices with the introduction of acid and steam, which allows to eliminate or significantly reduce their contact with the sorbent.Acid treatment is carried out at a pH of 2.2 to 4.2, so that in the first during the slurry apparatus ionite processing to maintain an optimal set parameters (pH of 2.6 to 4.6). The most preferred option proposed technology is conducting sorption at high pH in the head, in the course of the slurry, the apparatus to achieve the maximum saturation of the sorbent uranium and the subsequent decrease in pH to the tail unit, which allows for sufficient completeness opening of the useful component and eliminates the possibility of deposition of leached elements and coprecipitation with them uranium.Regulation of pH sorption in predetermined optimal range may be provided as the supply of reagents and commissioning pulp regenerated acidic ion exchanger, which is determined by the intensity of treatment of the resin in the system of sorption-desorption.
The following are examples of conduct processes for recovering uranium from ores on the proposed technology in comparison with the known method.For laboratory experiments was composed of the ore charge, in which silicate containing uranium breeds were represented trachydacite, felsite, conglomerate, andesite-basalts and granites; minerals of uranium pitchblende, coffinite, brannerite, uranium black, uranophane, urination and autunite, iron minerals magnetite, hematite, goethite and, to a minor extent, by jarosite and pyrite; carbonates consisted chiefly of calcite and magnesite, dolomite, siderite and ankerite. The content in the charge was, uranium 0,220; SiO266,7; Al2O314,1; Fetotal4,0; CO23-2.1, P2O50,3; Stotal0,2, etc.In the experiments used the crushed ore, particle size, solid 0,1 mm Oxidizer were dosed out in the original ore slurry, the density of which was 1.3 kg/m3. The process of extraction of uranium led PR is the major anion exchange resin brand AM-n-flow eightfold scheme, the residence time of the pulp and resin on each stage was one hour, the content of the sorbent supported 15% of the volume of the suspension. Desorption of uranium from a busy ion exchanger (regeneration of the resin) was carried out with a solution of H2SO4150-200 g/l and NO310-15 g/l, the output of the eluates was 2.0-2.5 volume on the volume of resin.In table. 1 shows the performance of hydrometallurgical processing of raw materials by known techniques. The ore slurry containing an oxidizing agent was videlacele for three hours at a pH of 1.2, then neutralized by ammonia water and the above scheme was simulated countercurrent process of sorption of uranium.Presented in table. 1 data shows that with increasing pH neutralization of from 1.8 to 4.6 extraction of uranium decreases with 94,1 to 76.8% of which is associated with the deposition of leached uranium in the solid phase of the pulp. When the most high extraction component 94,1% (experiment 1) observed the lowest saturation of the ion exchanger uranium 8.6%, and a significant concentration of its impurities (Fe 1.1 percent).Similar results were obtained when using as a neutralizing agent CaO.The process indicators that were proposed technology is shown in table. 2.Vyselki the wound with input regenerated acidic ion exchanger, output saturated resin was carried out at pH 4.6 to 2.0; desorption of uranium from a busy ion exchanger (regeneration of the sorbent) spent sulfuric-nitric acid solutions followed by submission of regenerated resin on the sorption of uranium. The residence time of the pulp and resin on stage, the parameters of desorption supported similarly to the simulation processing of the ore slurry by a known method.The obtained data (table. 2) show that in all cases, equal in comparison with the known method the extraction of uranium 94,1% of the proposed technology achieved a higher degree of concentration of the useful component of the sorbent 11,2-12,6% against 8.6-11.2% in the conventional method (table. 1), the iron content did not exceed 0.2% vs. 1.1% at the same time the technology has reduced the consumption of sulfuric acid from 110 kg/t up to 74 kg/soJustification the boundary of the parameter values of the proposed method for the selective extraction of uranium shown in the drawing and table. 3, 4 and 5. The graph shows the dependence of the content of iron in the solid phase from pH treatment of the pulp. The obtained curve shows that in the region of pH 4.6-2.6 degree of transfer of iron in the solution is minimal, while lowering the pH of acid DoD it in the liquid phase of the slurry, that, in turn, causes a significant increase in the consumption of solvent is sulfuric acid, increasing the concentration in solution of sulfate ions and iron and, thus, reduce the completeness of the saturation of the sorbent uranium.Accordingly, the graphical dependence shows that the minimum boundary value of the pH of the raw materials is of 2.0, which is confirmed by the indicators table. 3, obtained by simulation of the circuit eight-speed countercurrent acid-ionite processing of the pulp.The presented data (table. 3) show that when pH decreases from 2.0 to 1.6 and then to 1.0 acid consumption increases accordingly with 74 kg/t to 98 kg/t and 125 kg/t, the cost increase from 7.2 $ /t to respectively 8,2 $ /t and 8.8 $ /soArea pH input of the reactivated sorbent (final stage ionite processing of raw materials) is 2,0-3,4, with costs not exceeding 7,3 $ /t, the preferred area boundary values of pH with minimal cost to 7.0-7.1 $ /t defined 3,2-2,4.From the data table. 4 area boundary values pH o saturated resin is determined in the pH range of 4.6-2.6 iron content in the sorbent does not exceed 0.2% and its saturation with uranium compiled by the increased concentration of uranium on the sorbent to 10.5-9.9% and in the latter case, the increase of iron content on the ion exchanger. The maximum saturation of the sorbent is observed at pH values of 3.6 to 4.0.Similar patterns were obtained using for acid-ionite processing of the raw material resins EAP-AP and AMP.Thus, it is shown that the area in which the process of sorption of uranium, combined with the additional extraction of it from the solid phase of the ore pulp is in the range of pH values of 4.6-2,0; its lower boundary is determined by the minimum value of pH (2,0), when the reduction begins intensive transition of iron in solution, respectively, increasing the flow rate of the solvent and increasing the concentration of sulfate ions in the solution; the upper boundary is determined by the optimal saturation of the sorbent with the lowest amount of iron on it, above pH 4.6 concentration of uranium on the resin is significantly reduced.For the leaching of uranium without the presence of the resin region pH of the processing of the pulp is determined within the range of 4.2 to 2.2; the upper boundary value provides an extremely high pH of the sorption process 4,6, minimum value pH leaching is included in the above optimal region of the opening of iron-containing minerals (pH of 2.0).The limits of the pH of the pulp at the conclusion of the saturated sorbent and the input handle is 4,6-2,6 and 3,4-2.0 and preferred values respectively 4.0 and 3.6 and 3.2 to 2.4.In table. 5 presents the performance management process on the proposed technology in the field of optimal pH values (leaching 3.6V; output saturated sorbent 4,0; enter regenerated ion exchanger 2,8) at different temperatures of the processing of the pulp.Unit costs on the selective extraction of uranium from ore slurries, given its technological losses, amounted to $ 7.1 $ /t at a temperature of 40-60oC and 7.2 $ /t at a temperature of 30-70oC. Raising the temperature to 80oC, as well as its reduction to the 20oC, leads to increased costs to 7.4 $ /tons At identical temperatures processing unit costs by a known method was 9.6-9.9 $ /soIn General, the presented data show that the proposed method is compared with the known allows to reduce costs for hydrometallurgical processing uraniastrasse raw materials and to increase the selectivity of the extraction of uranium.
1. Method for the selective extraction of uranium from ores comprising grinding and wet grinding with obtaining pulp, acid leaching with the introduction of the oxidant, countercurrent sorption of uranium from the pulp when combined with leaching with the introduction of the resin, the saturated output of the ion exchanger, is that acid leaching is carried out at a pH of 4.2 to 2.2.2. The method according to p. 1, characterized in that when the output of the saturated ion exchanger support pH 4.6 to 2.6, preferably 4,0 3,5, and when entering the regenerated ion exchanger 3,4 2,0, preferably 2,4 3,2.3. The method according to p. 1, characterized in that the temperature acid leaching and sorption of pulp support 30 70oWith, preferably 40 to 60oC.4. The method according to p. 1, characterized in that the desorption of uranium from a busy ion exchanger exercise sulfuric-nitric acid solutions.
FIELD: rare, dispersed and radioactive metal metallurgy, in particular hydrometallurgy.
SUBSTANCE: invention relates to method for reprocessing of polymetal, multicomponent, thorium-containing radwastes, formed when reprocessing of various mineral, containing rare-earth elements, Nb, Ta, To, V, Zr, Hf, W, U, etc. Method includes treatment of solution and/or slurry with alkaline agent; introducing of sulfate-containing inorganic compound solution and barium chloride; treatment of obtained hydrate-sulfate slurry with iron chloride-containing solution, and separation of radioactive precipitate from solution by filtration. As alkali agent magnesia milk containing 50-200 g/dm2 of MgO is used; treatment is carried out up to pH 8-10; sodium sulfate in amount of 6-9 g Na2SO4/dm2 is introduced as solution of sulfate-containing inorganic compound; barium chloride solution is introduced in slurry in amount of 1.5-3 g BaCl2/dm2. Hydrate-sulfate slurry is treated with solution and/or slurry containing 0.8-16 Fe3+/dm2 (as referred to startingsolution) of iron chloride, followed by treatment with high molecular flocculating agent and holding without agitation for 0.5-2 h. Radioactive precipitate is separated from mother liquor, washed with water in volume ratio of 0.5-2:1; then washed with sodium chloride-containing solution and/or slurry in volume ratio of 0.5-2:1; radioactive precipitate is removed from filter and mixed with mineral oxides in amount of 0.5-0.8 kg MgO to 1 kg of precipitate. Formed pasty composition is fed in forms and/or lingots and presses with simultaneous heating up to 80-1200C.
EFFECT: filtrate with reduced radioactivity due to increased codeposition coefficient of natural Th-232-group radioactive nuclide, in particular Ra-224 and Ra-228, with radioactive precipitates.
10 cl, 1 ex
FIELD: chemical technology; recovery of deactivated and decontaminated radioactive industrial wastes.
SUBSTANCE: proposed method that can be used for deactivating and decontaminating industrial radioactive wastes incorporating Tb-232 and their daughter decay products (Ra-228, Ra-224), as well as rare-earth elements, Fe, Cr, Mn, Sl, Ti, Zr, Nb, Ta, Ca, Mg, Na, K, and the like includes dissolution of wastes, treatment of solutions or pulps with barium chloride, sulfuric acid, and lime milk, and separation of sediment from solution. Lime milk treatment is conducted to pH = 9 - 10 in the amount of 120-150% of total content of metal oxyhydrates stoichiometrically required for precipitation, pulp is filtered, and barium chloride in the amount of 0.4 - 1.8 kg of BaCl2 per 1 kg of CaCl2 contained in source solution or in pulp, as well as pre-diluted sulfuric acid spent 5 - 20 times in chlorine compressors in the amount of 0.5 - 2.5 kg of H2SO4 per 1 kg of BaCl2 are introduced in filtrate. Alternately introduced in sulfate pulp formed in the process are lime milk to pH = 11 - 12, then acid chloride wash effluents from equipment and industrial flats at pulp-to-effluents ratio of 1 : (2 - 3) to pH = 6.5 - 8.5, and pulp obtained is filtered. Decontaminated solution is discharged to sewerage system and sediment of barium and calcium sulfates and iron oxysulfate are mixed up with oxyhydrate sediment formed in source pulp neutralization process; then 35 - 45 mass percent of inert filler, 10 - 20 mass percent of magnesium oxide, and 15 -m 25 mass percent of magnesium chloride are introduced in pasty mixture formed in the process while continuously stirring ingredients. Compound obtained is subjected to heat treatment at temperature of 80 - 120 oC and compressed by applying pressure of 60 to 80 at.
EFFECT: reduced radioactivity of filtrates upon separation of radioactive cakes due to enhanced coprecipitation of natural radionuclides.
7 c, 1 ex
FIELD: chemical technology; deactivation and decontamination of radioactive industrial products and/or wastes.
SUBSTANCE: proposed method designed for deactivation and decontamination of radioactive industrial products and/or production wastes incorporating Th-232 and its daughter decay products (Ra-228, Ra-224), as well as rare-earth elements, Fe, Cr, Mn, Al, Ti, Zr, Nb, Ta, Ca, Mg, Na, K, and the like and that ensures high degree of coprecipitation of natural radionuclides of filtrates, confining of radioactive metals, and their conversion to environmentally safe form (non-dusting water-insoluble solid state) includes dissolution of wastes, their treatment with barium chloride, sulfuric acid, and lime milk, and separation of sediment from solution. Lime milk treatment is conducted to pH = 9-10 in the amount of 120-150% of that stoichiometrically required for precipitation of total content of metal oxyhydrate; then pulp is filtered and barium chloride is injected in filtrate in the amount of 0.4 - 1.8 kg of BaCl2 per 1 kg of CaCl2 contained in source solution or in pulp and pre-dissolved in sulfuric acid of chlorine compressors spent 5-20 times in the amount of 0.5 - 2.5 kg of H2SO4 per 1 kg of BaCl2. Then lime milk is added up to pH = 11 - 12 and acid chloride wash effluents of equipment and production floors are alternately introduced in sulfate pulp formed in the process at pulp-to-effluents ratio of 1 : (2-3) to pH = 6.5 - 8.5. Filtrate pulp produced in this way is filtered, decontaminated solution is discharged to sewerage system, sediment of barium and calcium sulfates and iron oxysulfate are mixed up with oxyhydrate sediment formed in source pulp neutralization, inert filler and 0.5 - 2 parts by weight of calcium sulfate are introduced in pasty mixture while continuously stirring them. Compound obtained in the process is placed in molds, held therein at temperature of 20 - 50 oC for 12 - 36 h, and compacted in blocks whose surfaces are treated with water-repelling material.
EFFECT: reduced radioactivity of filtrates upon separation of radioactive cakes.
8 cl, 1 dwg, 1 ex
FIELD: uranium technologies.
SUBSTANCE: method comprises sorption of uranium on low-basicity anionites, desorption of uranium, and recovery of finished product. In particular, uranium-saturated low-basicity anionite is converted into OH- form and uranium into soluble stable complex [UO2(CO3)3]-4 by treating sorbents with alkali metal and ammonium carbonate solutions.
EFFECT: achieved complete desorption of uranium and simultaneously sorbent is freed from poisons and other sorption components.
SUBSTANCE: extractant has bi-phosphorus acid and additionally has tri-phosphate with relation of said components (0,5-1,25):1. Method for producing extractant includes adding to 2-ethylhexanole of chlorine oxide of phosphorus with their relation (4,5-5,1):2,0, and with parameters determined by reaching fullness of passing of reaction, after that reaction mixture is exposed until full removal of formed chlorine hydrogen, then to received mixture 1 mole of water is added, mixture is exposed to full hydrolysis. Then mixture is washed ad water layer is separated from organic remainder, containing said bi-phosphoric acid and tri-phosphate.
EFFECT: higher efficiency.
2 cl, 1 dwg, 2 tbl, 4 ex
FIELD: hydraulic metallurgy.
SUBSTANCE: method comprises extracting saturated ionite from the pulp, washing it with water, desorbing uranium, washing desorbed ionite to decrease acidity, separating by wet screening into 1.0±0.2-mm size, extracting silicon from the under-screen product, and discharging it and above-screen product to the uranium sorption.
EFFECT: reduced ionite consumption.
1 cl, 1tbl
FIELD: processing uranium-containing products formed at extraction of uranium from solutions followed by re-extraction by means of ammonium carbonates; extraction of uranium and accompanying valid components from ores.
SUBSTANCE: proposed method includes thermal dissociation at sedimentation of uranium, entrapping of ammonia and carbon dioxide from waste gases. Thermal dissociation of uranium-containing ammonium carbonate solutions is performed at temperature of 70-85°C to pH= 6.5-5.9 at simultaneous blowing of gases by air; solutions obtained after thermal dissociation are separated from uranium-containing sediment and accompanying valid components, molybdenum for example are extracted from them.
EFFECT: enhanced efficiency of utilization of ammonia and carbon dioxide; high degree of separation of uranium and admixtures; extraction of accompanying valid components, molybdenum for example.
2 cl, 1 tbl, 2 ex
FIELD: technology of processing uranium-and fluorine-containing wastes.
SUBSTANCE: proposed method includes preparation of solutions from wastes, concentration of solutions by sedimentation of uranium followed by dissolving of sediments in nitric acid, extraction conversion of concentrated solutions with the use of tributyl phosphate in hydrocarbon thinner and sedimentation of ammonium polyuranates from re-extracts thus obtained. Sedimentation of uranium at stage of concentration is performed with the use of sodium hydroxide at pH= 9-10 and temperature of 60-90C. Proposed method enhances purification of uranium from fluorine due to enhanced sedimentation and filtration properties of sediments at concentration stage. Content of admixtures in triuranium octa-oxide powders obtained from re-extracts by sedimentation of ammonium polyuranates and subsequent calcination does not exceed specified norms.
EFFECT: enhanced efficiency.
1 dwg, 2 tbl, 1 ex
FIELD: production methods.
SUBSTANCE: method of monazite recycling includes the milling of the monazite, processing during the heating by substance of hydroxide of alkaline metal, generating of the salt of phosphor acid, dilution of the filter cake in the mineral acid with the following abstraction of rare earth elements (REE), thorium and uranium. Processing is done by substance of kalium hydroxide = 1:1.0-1.5 with obtaining the substance of triallyl phosphate kalium and precipitation, containing the hydroxide of thorium, uranium, REE, notopened monocyte and empty land, which is processing by azotic acid, extending the nitrate REE in the substance. It is importuned from the substance the carbonates of REE by kalium carbonate. The rest of cake is processing by the substance of kalium carbonate with translating uranium into the substance and following importuning as dihydroxide dioxuranium and the final processing of the cake by the substance of azotic acid with generating thorium into the substance by importuning of thorium by the substance of kalium carbonate. The mother water from the importuning of REE, thorium and uranium and three kalium phosphate is distained to the producing of manuring. The substance of three kalium phosphate and hydroxide kalium is vapored , and it is separated crystal three kalium phosphate, and hydroxide kalium is distained to the head of process. The rest after processing by azotic acid not opened monocyte is distained to the head of process.
EFFECT: simplifying of the process and more effective using of all components of monoyte.
6 cl, 1 ex
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