Method of monazite recycling

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

 

The present invention relates to technology of rare and radioactive elements. The mineral monazite is a phosphate of thorium and rare earth elements (REE), is one of the main sources of REE. The presence of thorium allows us to consider the monazite as a potential source of thorium raw material of nuclear power. Over the last decade, published a large number of works in the field of technology monazite. Typically, the main task, which the researchers decide in technology monazite is strong enough destruction of the crystal lattice phosphate REE and thorium. Existing methods involve mainly two solutions: processing of monazite aqueous solutions of mineral acids or alkalis [1-7] or sintering with carbonate-alkaline compounds of metals of the first group [8-13].

The closest technical solution and the achieved result is a method of processing monazite processing finely crushed ore with a concentrated solution of sodium hydroxide at a temperature of 140 C. [14]. Monazite concentrate is ground to a fineness of grain - 0,048 mm, treated with 45%NaOH solution at 140°and With stirring for 3 hours. The consumption of alkali is 150% of the weight of monazite. Subsequent treatment with water to separate phosphorus from hydrates and hydroxides dissolve REE in hydrochloric acid. KEK is the ass opening is subjected to processing with the subsequent extraction of uranium and thorium. Due to low profitability REE processing in this way, phosphate minerals, such as Krasnoufimsky monazite, became unprofitable. In addition, there is a large amount of wastewater containing illiquid product is sodium nitrate. To simplify the process and reduce the cost of processing products, the authors propose the following technical solution. Monazite is crushed to a particle size of 0.05-0.1 mm, is mixed with a solution of potassium hydroxide concentration of 450-500 g/l with a ratio of monazite : potassium hydroxide = 1:1.0 to 1.5 and heated in the reactor under stirring for 2-4 hours. The temperature of the support is equal 110-140°C. Then the pulp is diluted with water 2-3 times and filtered to separate the precipitate of hydroxides of thorium, rare earth elements and uranium. The filtrate is evaporated in 3-4 times, cooled to 20-25°and separating the crystals tribalista. The mother liquor is sent to the head of the process for preparation of a solution of potassium hydroxide. The precipitate hydroxides of thorium, uranium, REE, unopened monazite and waste rock is treated with a solution of nitric acid at pH 3.5-4.5. Nitrates REE pass into the aqueous phase which is separated by filtration. From the solution obtained after decontamination, which is carried out by known methods, secrete carbonate, precipitating REE potassium carbonate. Royal solutions containing Nitra is potassium, direct the production of fertilizers. The remaining cake is treated with potassium carbonate solution, and the uranium is dissolved into the solution in the form of tricarbonate complex. Uranium from solution is isolated by acidification and subsequent deposition of dihydroxide dioxolane. Cake containing thorium, unopened monazite and waste rock is treated with nitric acid with 40-50% of the excess when heated for a full translation of thorium residues and metal hydroxides in solution. Thorium solution is separated by filtration and extracted thorium precipitation with potassium carbonate. Carbonate thorium processed by known methods. The remaining cake contains unopened monazite and waste rock. It is sent for shredding and separation of waste rock, and monazite return to the head of the process. Royal solutions containing nitrate and potassium phosphate, processed with the production of fertilizers. For this mother solution containing potassium nitrate, evaporated and cooled vykristallizovyvalas potassium nitrate. The part of the mother solutions combine with crystals of potassium phosphate, add phosphoric acid and receive complex nitrogen-phosphorus-potassium fertilizer. The positive effect is to make it easier and more effective use of all components of monazite.

Example 1.

A portion of monazite weighing 100 g to grind in a mortar to a particle size of 0.05-0.1 mm and repulpable in 300 ml of a solution of potassium hydroxide. Weight of potassium hydroxide and 150 g, concentration of 450 g/L. the Slurry was heated to boiling point for 4 hours. The filter cake was washed with 300 ml of hot water. The volume of filtrate and wash water 550 ml (solution 1). The content in solution 1: potassium phosphate 166 g/l, potassium hydroxide 181 g/L. Precipitate hydroxides of thorium, uranium, REE, unopened monazite and waste treated under stirring with a solution of nitric acid at pH 4.0 to 4.5. Separated by filtering a solution of the nitrates of rare-earth elements. The precipitate was washed with hot water.

The amount of leaching and the mother liquor 620 ml (solution 2).The content of thorium in solution of 0.1 g/l, REE-101,3 g/L. the Solution was subjected to standard cleansing nitrates of rare-earth elements from thorium pH precipitation. To the obtained solution of nitrates was added 700 ml of potassium carbonate solution, the concentration of 142 g/l Residue on the filter is washed with 400 ml of hot water. To the combined filtrate and the wash water added nitric acid to pH 5-6. The final solution volume of 1500 ml (solution 3). The content in solution 3 potassium nitrate - 185,3 g/l wet Sediment REE carbonates contained 57 g REE in the calculation of the oxides. The precipitate hydroxides of thorium, uranium, non-monazite and waste processed 25 ml of potassium carbonate solution, a concentration of 100 g/L. the Slurry was filtered. The precipitate was washed with 50 ml of hot water. The volume of filtrate and washing solution 75 ml (solution 4). Content from the Ana in a solution of 13.3 g/l, thorium 0.2 g/l In the solution introduced nitric acid to pH 5-6. The residue of dihydroxide dioxolane separated by filtration. The remaining cake containing thorium, undecomposed monazite and barren rock, treated with nitric acid (12 g) when heated to a temperature of 90-95°C for 2 hours. The slurry was filtered, the filter cake thoroughly washed with water. The volume of filtrate and washing solution 96 ml. Content of thorium in solution (solution 5) and 70.8 g/l, uranium 0.15 g/l Of the resulting solution were allocated concentrate thorium precipitation with potassium carbonate and subsequent filtering. Cake containing unopened monazite and waste rock mass 16 g, was subjected to grinding and milling with the Department of waste rock. The monazite concentrate was added to a new portion monazite feedstock. Solution 1 was evaporated to 170 ml and cooled. After filtration and washing of the crystals obtained 62 g tribalista and 200 ml of a solution containing 500 g/l of potassium hydroxide and 150 g/l of tribalista. The solution was sent to the head of the process for opening a new portion of the concentrate. Tribalistic combined with solution 3 and solution 6 was addedphosphoric acid to pH 3.5. Subsequentoparka and granulation results in a complex nitrogen-phosphorus-potassium fertilizers known methods.

Recommended parameters selected based on the optimal conditions of opening and the Department is of valuable products. With decreasing temperature the opening or the ratio of monazite and potassium hydroxide decreases the degree of opening, excessive introduction of hydroxide potassium is not economically justified.

The advantage of the proposed method in comparison with the prototype is as follows:

1. The use of potassium ion at all stages of the processing of monazite allows you to save valuable potassium and implement it in the form of liquid and quite expensive factorylink fertilizer, which largely reduce the manufacturing cost. Pre-feasibility calculations show that ceteris paribus, sales of products in the processing of 1 tonne of monazite obtained by the proposed method, two times more than the method described in the prototype.

Whplesale purification of potassium hydroxide from tribalista, as accumulated in the course of a few autopsies circulating potassium hydroxide containing impurities, is withdrawn from the system for the operation of obtaining fertilizer.

Literature

1. Geelan, Touzinsky, Wijerama, Evercom. Thorium, its raw materials, chemistry and technology. M: Atomizdat, 1960, 224 S.

2. F.L.Cuthbert. Thorium production technology. Addison-Wisley, USA, 1958.

3. D.W.Pearce, R.A.Hanson, J.C.Butler. In: Inorganic syntheses. II. Conrad Fernelius (Editor-in-chif) at al., New Yorc, McGraw-Hill Book Co., 1946, p.38-43. The extraction of rare earth minerals. I.Monazite and xenotim.

4. E.S.Pilkington, W.Wylie. Rare earth and torium compounds from monazite. J.Soc.Chem. Ind.(London) 1947, v.66, p.387-394.

5. A.E.Bearse, G.D.Calkins, J.W.Clegg, R.B.Filbert. Thorium and rare earth from monazite. Chem. Eng. Progr., 1954, v.50, p.235-239.

6. Geelan, Touzinsky, Kwilu, Mvidoumou. Metallurgy of thorium. Reports of the Soviet delegation at the International conference on peaceful uses of atomic energy, Geneva, 1955. Studies in Geology, chemistry and metallurgy. M: From the USSR, 1955, s.

7. Reginald W.Blundell. United Kingdom Atomic Energy Authority. Recovery of Thorium from monazite. Brit. pat. 783628, Sept. 25, 1957.

8. A.Audsley, W.D.Jamrack, A.E.OIdbury, R.A.Wells. Resently developed processes for extraction and purification of thorium. Proc. UN Intern. Conf. Peaceful Uses At. Energy, 2nd, Geneva, 1958, v.3, p.216-228.

9. N.N.Kurup, S.S.Moosath. Travancore monazite. VI. Investigation on the solid-solid reaction between monazite and sodium carbonate by differential-thermal analysis and by x-ray diffraction. Indian Acad. Sci., 1958, 48A, p.76-83.

10. Gasperson, Touzinsky. The improvement of the alkaline decomposition of monazite. Atomic energy, 1957, V. 3, 9, s.

11. C. de Ronden, M.F.Peltier. FP No. 995112, 1949/5.

12. C.R.Bohm Chem. Ind., 1906, v.29, p.450-462.

13. Hisaichi Arakawa. The separation and purification of rare-earth elements from monazite. Bull. Chem. Soc. Japan, 1948, v.21, p.43-48.

14. A.E.Bearse, G.D.Calkins, J.W.Clegg, R.B.Filbert. Thorium and rare earth from monazite. Chem. Eng. Progr., 1954, v.50, p.235-239.

1. The method of processing of monazite, including grinding, processing, when heated with a solution of alkali metal hydroxide, the allocation of salts of phosphoric acid, dissolution of the oxide in the mineral acid, followed by extraction of rare earth elements (REE), thorium iorana, characterized in that the treatment is carried out with a solution of potassium hydroxide at a ratio (wt.): monazite: potassium hydroxide = 1:1,0-1,5 obtaining solution tribalista, potassium hydroxide and the precipitate containing hydroxides of thorium, uranium, REE, unopened monazite and waste, which is treated with nitric acid, removing nitrates REE in solution, are precipitated from solution REE carbonates potassium carbonate, the remaining cake is treated with a solution of potassium carbonate with the transfer of uranium in solution and subsequent precipitation as dihydroxide dioxolane and final processing of the cake with a solution of nitric acid extraction of thorium in solution, precipitation of the thorium solution of potassium carbonate, and uterine fluids from the deposition of rare-earth elements, thorium, uranium and tribalistic is directed to the production of fertilizers.

2. The method according to claim 1, characterized in that the processing maintain the temperature of 110-140°C.

3. The method according to claim 1, characterized in that the solution tribalista and potassium hydroxide evaporated, separated crystalline tribalistic, and potassium hydroxide sent to the head of the process.

4. The method according to claim 1, characterized in that unopened monazite sent to the head of the process.

5. The method according to claim 1, wherein the mother solution containing potassium nitrate, evaporated and cooled vykristallizovyvalas potassium nitrate.

6. The method according to claim 1, trichosis fact, what uterine solutions from deposition of rare-earth elements, thorium, uranium and tribalistic combine, add phosphoric acid and the resulting solution was evaporated to obtain the nitrogen-phosphorus-potassium fertilizers.



 

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FIELD: mining industry.

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EFFECT: the invention ensures a decrease in two-two and a half times of the volume of the used cleansing solutions at provision of a high degree of extraction of compounds of titanium and other target products and a decreased amount of impurities of calcium and strontium in the sodium fluorotitanate.

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FIELD: non-ferrous metallurgy; methods of production of scandium-containing ligatures.

SUBSTANCE: the invention is pertaining to the field of non-ferrous metallurgy. The method of production of scandium-containing addition alloys includes a metallothermic restoration in halogenide melts. According to the invention the halogenide melt containing 1.0-1.4 mass % of scandium oxide is added with 1.4-1.7 mass % of zirconium oxide and conduct restoration by an alloy of aluminum with magnesium at the ratio of the halogenide melt to the aluminum-magnesium alloy from 1.2 up to 1.6. The technical result of the invention is production of a synthesized addition alloy containing scandium and zirconium with the maximal strengthening effect, decreased value of the produced addition alloy (by 30-40 %) due to decrease of consumption of the cost intensive scandium oxide by 50 %.

EFFECT: the invention ensures production of a synthesized scandium and zirconium ligature with maximal strength, allows to decrease significantly its production cost and consumption of expensive scandium oxide.

1 tbl, 1 ex

FIELD: metallurgy; hydrochemical methods of a complex processing of a multicomponent, polymetallic scrap.

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EFFECT: the invention allows to concentrate radioactive metals in the "head" of the process, to transfer the process secondary wastes in the ecologically secure deficient and expensive black thermo-resistant inorganic pigments.

5 cl, 1 ex

FIELD: non-iron metallurgy, in particular scandium oxide recovery from industrial waste.

SUBSTANCE: method for preparation of scandium oxide from red mud being waste of alumina production includes: multiple subsequent leaching of red mud with mixture of sodium carbonate and hydrocarbonate solutions; washing and precipitate separation; addition into obtained solution zinc oxide, dissolved in sodium hydroxide; solution holding at elevated temperature under agitation; precipitate separation and treatment with sodium hydroxide solution at boiling temperature; separation, washing, and drying of obtained product followed by scandium oxide recovery using known methods. Leaching is carried out by passing through mixture of sodium carbonate and hydrocarbonate solutions gas-air mixture containing 10-17 vol.% of carbon dioxide, and repeated up to scandium oxide concentration not less than 50 g/m3; solid sodium hydroxide is introduced into solution to adjust concentration up to 2-3.5 g/m3 as calculated to Na2O (caustic); and mixture is hold at >=800C followed by flocculating agent addition, holding, and separation of precipitate being a titanium concentrate. Obtained mixture is electrolyzed with solid electrode, cathode current density of 2-4 A/dm3, at 50-750C for 1-2 h to purify from impurities. Zinc oxide solution in sodium hydroxide is added into purified after electrolysis solution up to ratio ZnO/Sc2O3 = (10-25):1, and flocculating agent is introduced. Solution is hold at 100-1020C for 4-8 h. Separated precipitate is treated with 5-12 % sodium hydroxide solution, flocculating agent is introduced again in amount of 2-3 g/m3, mixture is hold, and precipitate is separated. Method of present invention is useful in bauxite reprocessing to obtain alumina.

EFFECT: improved recovery ratio of finished product into concentrate; decreased impurity concentration in concentrate, reduced sodium hydrocarbonate consumption, as well as reduced process time due to decreased time of fine-dispersed precipitate.

2 cl, 2 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: chemistry.

SUBSTANCE: method implies uranium hot leaching with strong nitric acid and separation of aqueous phase from non-soluble residue prior to extraction processing. Leaching is carried out, weight ratio of nitric acid to uranium being (0.75-0.84): 1, at 85-100°ะก, which results in aqueous phase uranium concentration of 700-800 g/l. Hot pulp is diluted with dilute nitric acid solutions to uranium concentration of 350-500 g/l in pulp aqueous phase and nitric acid concentration of ca. 1.0 mol/l, which is suitable for extraction processing aqueous phase. Then aqueous phase is separated from the solid residue.

EFFECT: resulting nitric-acid uranium solutions can be easily separated from solid phase and are suspension-free; solutions are suitable for extraction processing.

1 tbl, 1 ex

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