Method for separating and purifying 226Ra from waste residues

Abstract

The invention discloses a method for separating and purifying 226Ra from waste residues. Comprising the following steps: pretreating the waste residue containing 226Ra to obtain a first sample of which the particle size meets the requirement; removing petroleum substances in the first sample to obtain a second sample; digesting the second sample, and filtering to obtain supernate of the second sample; adopting a sulfate coprecipitation method to obtain a radium coprecipitate in the supernate of the second sample, and removing impurities; purifying to obtain a radium coprecipitate mixed solution; separating Ra < 2 + > and Ba < 2 + > in the radium coprecipitate mixed solution; and purifying the separated Ra < 2 + > to obtain a final product. The method for separating and purifying the 226Ra from the waste residues, which is simple and can be industrialized, is provided by carrying out pretreatment and digestion on a pretreatment sample of the waste residues, carrying out coprecipitation Ra-Ba separation and Ra purification on Ra after forming a radium coprecipitate.

Description

Technical Field

[0001] The present invention relates to the technical field of radium element purification and separation, which is a method for separating and purifying radium from waste residue. 226 Ra method, especially for separating and purifying waste residues from oil and gas industry 226 Ra's method. Background Art

[0002] As a natural radioactive element, radium is widely distributed in the earth's crust. Its main isotope 226 Ra has a half-life of 1600 years. It is associated with U-Th and is a part of the U(4n+2) radioactive decay chain in nature. In 1898, Marie Curie separated natural radium from pitchblende. 226 Ra radioactive sources (mostly in the form of radium needles) were widely used in the treatment of bladder cancer, cervical cancer, head or neck tumors, etc. in the last century. 226 Photonuclear transmutation production of Ra 225 Ac has made a breakthrough in the method, with higher process efficiency and significantly shortened production cycle. It has begun to be industrialized on a global scale, making the once "waste" 226 Ra radioactive sources have become a hot commodity. However, the world's existing radium reserves are limited, only in kg, and cannot meet the demand. 225 Ac has a long-term production demand, and the existing waste radium sources in various countries are favored and competed for by major isotope manufacturers. It is crucial to find other ways to obtain radium. Although radium isotopes are widely present in the earth's environment, their content is extremely low, and they are difficult to extract and produce. They are commercially expensive and difficult to obtain. The current mature method of producing radium is to extract it from uranium ore. It is generally used as a by-product of uranium production and is mainly separated and extracted again from the slag after uranium extraction. The barium sulfate-radium method was used in the early days. This method is suitable for the crude separation of large amounts of radium salts, but the chemical purity of the resulting radium salts is not high, generally in the range of 60% to 80%, which cannot meet the production requirements of the electron accelerator photonuclear reaction method. 225 Ac pair 226 Ra target purity requirements. Therefore, it is urgent to develop a new radium extraction and preparation technology to meet 225 Ac production for high purity 226 Ra's needs. Summary of the invention

[0003] The invention provides a method for separating and purifying waste residue. 226 Ra method is used to solve the problem of electron accelerator photonuclear reaction production 225 Ac 226 Ra target material supply is extremely tight, and we provide high purity 226 Ra. The specific plan is:

[0004] A method for separating and purifying waste residue 226The method of Ra, the method comprising the following steps:

[0005] S1, pre-treat the waste residue containing 226 Ra to obtain a first sample with a particle size meeting the requirements;

[0006] S2, remove the petroleum substances in the first sample to obtain a second sample;

[0007] S3, after digesting and filtering the second sample, obtain the supernatant of the second sample;

[0008] S4, use the sulfate coprecipitation method to obtain the radium coprecipitate in the supernatant of the second sample and remove impurities;

[0009] S5, purify the radium coprecipitate after impurity removal to obtain a radium coprecipitate mixture;

[0010] S6, use SR resin to separate Ra 2+ and Ba 2+ ;

[0011] S7, purify the separated Ra 2+ , to obtain the final product.

[0012] Preferably, the removal of petroleum substances in S2 is carried out by extraction method, and the defatting extractant is a low-boiling organic solvent that can dissolve or extract petroleum substances.

[0013] Preferably, the digestion method in S3 includes any one of mixed acid dissolution, mixed acid leaching, and basic melting.

[0014] Preferably, the mixed acid digestion includes any one of HNO 3 +HF dissolution or HNO 3 +HCl dissolution.

[0015] Preferably, the mixed acid leaching includes any one of HNO 3 +HF leaching, HNO 3 +HCl leaching, HNO 3 leaching, and the concentration of the mixed acid used in the mixed acid leaching is 6mol / L - 10mol / L.

[0016] Preferably, the basic substances in the basic melting include any one of sodium hydroxide, potassium hydroxide, sodium borate, and potassium fluoride.

[0017] Preferably, the specific process of obtaining the radium coprecipitate in S4 is:

[0018] 1) Adjust the PH in the supernatant to <2;

[0019] 2) Add sulfates and acetic acid to the supernatant with pH < 2, and obtain a mixed product after sufficient reaction;

[0020] 3) After cooling the mixed product to 40 °C, dropwise add 0.5% barium chloride dihydrate solution until the radium lithium ions in the supernatant are completely formed into radium coprecipitates;

[0021] 4) Continue to cool the mixed solution of radium coprecipitates to room temperature, and centrifuge to collect the radium coprecipitates.

[0022] Preferably, the purification process of the radium coprecipitates after impurity removal in S5 is as follows:

[0023] 1) Add a carbonate solution to the radium coprecipitates after impurity removal to convert the sulfate precipitate in the radium coprecipitates into a carbonate precipitate, and obtain a mixture;

[0024] 2) Add an acidic solution to the mixture to completely dissolve the precipitate in the mixture, and obtain a pure mixed solution of radium coprecipitates;

[0025] The carbonate includes Na 2 CO 3 、K 2 CO 3 and any one of other inorganic or organic acid salts that achieve conversion by using the difference in solubility product.

[0026] Preferably, the purification in S6 adopts the resin extraction chromatography method.

[0027] Compared with the prior art, the beneficial effects of the present application are as follows:

[0028] The present application provides a simple and industrializable method for separating and purifying 226 Ra from waste residues by pre-treating the waste residues, pre-treating the samples, digesting, forming radium coprecipitates, and then performing Ra coprecipitation, Ra-Ba separation, and Ra purification;

[0029] The present application pre-treats the samples to make their particle size less than 80 mesh to achieve the effect / function of rapid digestion;

[0030] Impurities are removed multiple times throughout the process to increase its purity to over 99%;

[0031] Efficient extraction of radium is achieved through digestion;

[0032] The method of separating Ra-Ba using SR resin has fewer steps, faster time, a simpler system during industrialization, and convenient waste transfer, recovery, and treatment compared with the traditional recrystallization separation method.

[0033] First dissolve the frit with HCl solution, evaporate to near dryness, and then dissolve with dilute nitric acid, which can accelerate the dissolution rate.

[0034] The method provided by this application can achieve a recovery rate of radium in the waste residue greater than 80% and a chemical purity of the radium product greater than 98% according to the radium-containing waste residues from different sources, meeting the requirements of industrial applications. Thus, it provides a new idea for extracting and separating radium from waste residues, which not only treats the radioactive waste generated in related industries but also obtains the currently scarce industrial raw materials at the same time. Specific Embodiments

[0035] A method for separating and purifying 226 Ra from waste residues, the method comprising the following steps:

[0036] S1, crushing and grinding the waste residue containing 226 Ra to a particle size less than 80 mesh, and drying it at 80°C to 150°C for 120 min to 240 min until completely dry, to obtain a first sample;

[0037] S2, using a Soxhlet extraction device to remove petroleum substances from the first sample, and drying it under vacuum at 150°C to 250°C for 60 min to 120 min until completely dry, to obtain a second sample;

[0038] S3, digesting the second sample to obtain a second sample solution;

[0039] S4, using the BaSO 4 coprecipitation method to coprecipitate radium, centrifuging to obtain the radium coprecipitate, and removing impurities;

[0040] S5, adding a weak base to the radium coprecipitate after impurity removal to convert the sulfate in the radium coprecipitate into carbonate that is easily soluble in acid, forming a first mixed solution; adding an acid solution to the first mixture to dissolve the carbonate therein, to obtain a second mixed solution, that is, obtaining a mixed solution of the purified radium coprecipitate;

[0041] S6, separating the second mixed solution using an SR resin to obtain a Ra 2+ effluent and a Ba 2+ effluent;

[0042] S7, evaporating the Ra 2+ effluent to dryness, and purifying to obtain pure Ra(NO 3 ) 2 powder.

[0043] Furthermore, the removal of petroleum substances in S2 adopts the extraction method, and the deoiling extractant is a low-boiling organic solvent that can dissolve or extract petroleum substances.

[0044] It should be noted that: in this application, the extraction solvent is a low-boiling organic solvent, and the extraction time is determined according to the selected organic solvent.

[0045] Further, the digestion method in S3 includes any one of mixed acid dissolution, mixed acid leaching, and basic melting.

[0046] Further, the mixed acid digestion includes any one of HNO 3 +HF dissolution or HNO 3 +HCl dissolution.

[0047] Further, the mixed acid leaching includes any one of HNO 3 +HF leaching, HNO 3 +HCl leaching, and HNO 3 leaching, wherein the concentration of the mixed acid used in the mixed acid leaching is 6 mol / L to 10 mol / L.

[0048] Further, the basic substance in the basic melting includes any one of sodium hydroxide, potassium hydroxide, sodium borate, and potassium fluoride.

[0049] It should be noted that: according to the different characteristics of the obtained second sample during the digestion process, the second sample can also be treated by using a single acid solvent or mixed acid leaching. In this application, acid digestion is achieved by using a mixed acid solvent and mixed acid leaching. The process of mixed acid dissolution is as follows:

[0050] 1) Dissolve the second sample in a mixed mixed acid solution (such as the above-mentioned HNO 3 +HF solution or HNO 3 +HCl solution);

[0051] 2) After complete dissolution, heat and evaporate to dryness, and repeat the above steps if necessary until the solid is completely dissolved and clarified;

[0052] 3) Dissolve with dilute nitric acid (HNO 3 );

[0053] 4) After filtering the dissolution solution, retain the supernatant containing radium and discard other solid matrices;

[0054] The process of basic melting digestion is specifically as follows:

[0055] 1) For the second sample with more insoluble organic matter, digest it by high-temperature melting with a strong base (such as strong basic substances like sodium hydroxide (NaOH), potassium hydroxide (KOH), sodium borate (NaBO3), potassium fluoride (KF), etc.);

[0056] 2) Dissolve the fused mass after cooling with HCl solution, evaporate to near dryness, and then dissolve with dilute nitric acid (HNO 3 );

[0057] 3) After complete dissolution, filter the dissolution solution, and retain the supernatant containing radium, discarding a small amount of impurity solids;

[0058] The process of acid leaching is specifically as follows: In the second sample, appropriate mixed inorganic acid is added according to a solid-liquid ratio of 1 g: 10 ml to 15 ml, and it is continuously stirred at 90 °C to 120 °C for 1 to 2 hours to leach out radium elements; after filtration, the residue is leached again with a general amount of mixed acid under the same conditions for 1 hour, and then filtered, and the supernatant is combined.

[0059] Further, the specific process of obtaining the radium coprecipitate in the second sample solution by the sulfate coprecipitation method is as follows:

[0060] 1) Adjust the pH of the supernatant to < 2;

[0061] 2) Add sulfate and acetic acid to the supernatant with pH < 2, and keep stirring at 80 °C to 100 °C for 5 min to 20 min. After sufficient reaction, a mixed product is obtained.

[0062] 3) After cooling the mixed product to 40 °C, slowly add 0.5 ml to 1 ml of 0.5% barium chloride dihydrate solution drop by drop to observe the formation of the radium coprecipitate. Ensure that the SO 4 2+ ions are in excess during the whole process;

[0063] 4) Continue to cool for 10 min to 20 min, and centrifuge to collect the radium coprecipitate;

[0064] 5) Wash the radium coprecipitate with deionized water multiple times to remove impurities and unreacted reagents, thus obtaining the radium coprecipitate after impurity removal.

[0065] Further, the purification process of the radium coprecipitate after impurity removal in S5 is as follows:

[0066] 1) Add a carbonate solution to the radium coprecipitate after impurity removal to convert the sulfate precipitate in the radium coprecipitate into a carbonate precipitate, obtaining a mixture;

[0067] 2) Add an acidic solution to the mixture to completely dissolve the precipitate in the mixture, obtaining a pure radium coprecipitate mixture solution;

[0068] The carbonate includes Na 2 CO 3 、K 2 CO 3 and any one of other inorganic or organic acid salts that achieve conversion by using the difference in solubility product.

[0069] Further, the purification in S6 adopts the resin extraction chromatography method.

[0070] It should be noted that: in this application, Ra 2+ The purification of 2+ includes but is not limited to any one of DGA resin extraction chromatography, LN resin extraction chromatography, or resin extraction chromatography with similar extractants.

[0071] This application is also applicable to the utilization of radium-containing waste in other industries involving geological resources other than uranium industrial slag (which has a high radium content and is relatively easy to extract), including but not limited to petroleum, natural gas, phosphate industry, rare earth mining and metallurgy, etc.

[0072] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0073] Due to the high concentration of radium in the internal scale layers of pipelines and equipment such as oil and gas fields, it is generally treated as radioactive waste. Due to the high temperature and high pressure conditions underground, the radionuclide radium is in a dissolved state in the formation. Generally speaking, the higher the salt concentration in the formation water, the higher the concentration of natural radioactive substances including radium. When water is produced from underground together with oil, due to the decrease in temperature and pressure, the solubility of various substances also decreases accordingly, thus forming scale layers of calcium, barium, and strontium carbonates and sulfates in pipelines and equipment, and radium also exists in the scale layers, with the highest concentration up to 100000 Bq / g. Such radium-containing polluted sites include crude oil / natural gas transmission pipelines, natural gas condensate storage tanks, sludge pits, filtration equipment (separator inlet device), fractionators, condensers, brine disposal / injection wells, etc. The following examples respectively use the residues of production tubing, uranium mine tailings, phosphate ore slag, and gas field waste residue as waste residue samples, and use the method of this application to separate and purify them to obtain radium ( 226 Ra) therein.

[0074] Example 1

[0075] This example provides a waste residue raw material using the residue of production tubing as the raw material for extracting radium ( 226 Ra), and obtains a scarce raw material for the production of medical isotopes therefrom. The specific process is as follows:

[0076] S1, pulverize and grind the waste residue sample (4.6 g) containing 226 Ra to a particle size less than 80 mesh, and dry it at 80°C to 150°C for 120 min to 240 min. After complete drying, a first sample meeting the particle size requirements is obtained;

[0077] S2, Use a Soxhlet extraction device to remove petroleum substances from the first sample at 70°C to 90°C to obtain a second sample. The extraction solvent used in the Soxhlet extraction device is 20 ml to 40 ml of turpentine, and the extraction time is 10 min to 30 min;

[0078] S3, Vacuum dry the petroleum-removed sample (i.e., the second sample) at 150°C to 250°C for 60 min to 120 min to obtain a completely dry second sample;

[0079] S4, Digest the completely dry second sample by acid dissolution with HNO 3 +HF to obtain a second sample solution;

[0080] S5, After filtering the second sample solution, obtain the supernatant of the second sample solution. Adjust the acidity of the supernatant to make the pH of the supernatant < 2. Use the BaSO 4 coprecipitation method to coprecipitate radium to obtain a radium coprecipitate. The specific process is as follows:

[0081] 1) Add 5 ml of 20% sodium sulfate solution, add acetic acid to 0.4 mol / L, and stir at 80°C to 100°C for 5 min to 20 min until the reaction is complete;

[0082] 2) After the reaction is complete, cool to below 40°C, and gradually add 0.5 ml to 1 ml of 0.5% barium chloride dihydrate solution to observe the formation of the radium coprecipitate until the radium lithium ions in the supernatant are completely formed into the radium coprecipitate. Ensure that the SO 4 2+ ions are in excess during this process;

[0083] 3) Continue to cool for 10 min to 20 min until the mixed solution of the radium coprecipitate reaches room temperature, and centrifuge to collect the radium coprecipitate.

[0084] S6, Rinse the radium coprecipitate with deionized water multiple times to remove impurities and unreacted reagents;

[0085] S7, Use 50 ml to 80 ml of saturated Na 2 CO 3 solution to oscillate (stir) at 60°C to 90°C for 2 hours to 5 hours to convert the sulfate precipitate into a carbonate precipitate. The purpose is to convert the sulfate precipitate that is difficult to dissolve in acid into a carbonate that is easy to dissolve in acid;

[0086] S8, Completely dissolve the carbonate precipitate with dilute nitric acid (1 mol / L to 2 mol / L) to obtain a mixed solution of the radium coprecipitate;

[0087] S9, Use SR resin to separate Ra 2+ and Ba 2+ , and the specific process is as follows:

[0088] Adjust the acidity of dilute nitric acid to 8 mol / L HNO 3 ;

[0089] After equilibrating the resin column with 8 mol / L HNO 3 solution, load the above-obtained radium coprecipitate mixture onto the column, and elute with 4 to 6 column volumes of 8 mol / L HNO 3 solution, and combine the effluent. Desorb Ba with 0.01 mol / L HNO 3 solution and regenerate the resin; 2+ Evaporate the effluent of Ra

[0090] to dryness to obtain relatively pure Ra(NO 2+ ) 3 powder, and purify it with DGA resin, LN resin, etc. if necessary. 2 It should be noted that:

[0091] In S2 of this embodiment, the extraction solvent is turpentine, and its extraction time is 10 min to 30 min; among them, turpentine includes one of low-boiling organic solvents such as petroleum ether, diethyl ether, n-hexane, chloroform, gasoline, etc.

[0092] In S4 of this embodiment, the digestion process of the second sample is as follows: Add 100 ml of HNO

[0093] + HF (8 mol / L HNO 3 + 5% HF) appropriate mixed inorganic acid, stir continuously at 90°C to 120°C for 1 to 2 hours to leach out radium element; after filtration, leach the residue with 50 ml of mixed acid under the same conditions for another 1 hour, filter, and combine the supernatant. 3 In this embodiment, adjust the acidity of the filtered supernatant to pH < 2. This step creates a suitable chemical environment for the subsequent coprecipitation reaction. A lower value can inhibit some side reactions that may interfere with the precipitation reaction, and at the same time, it can also make the ionic form in the solution more conducive to the coprecipitation process of radium.

[0094] Example Two

[0095] This embodiment provides a waste residue raw material taking the scale of production tubing as the raw material for extracting radium(

[0096] Ra), and obtains a scarce raw material for producing medical isotopes from it. The specific process is as follows: 226 S1, containing

[0097] S1, containing 226The waste residue sample of Ra (5.3 g) is crushed and ground until the particle size is less than 80 mesh, dried at 80 °C to 150 °C for 120 min to 240 min, and after complete drying, the first sample meeting the particle size requirements is obtained;

[0098] S2, Using a Soxhlet extraction device to remove petroleum substances in the first sample at 70 °C to 90 °C to obtain a second sample. The extraction solvent used in the Soxhlet extraction device is 20 ml to 40 ml of turpentine, and the extraction time is 10 min to 30 min;

[0099] S3, The sample after removing petroleum (i.e., the second sample) is vacuum dried at 150 °C to 250 °C for 60 min to 120 min to obtain a completely dry second sample;

[0100] S4, The completely dry second sample is digested by the NaOH melting method and dissolved with 0.5 mol / L HNO 3 dissolve;

[0101] S5, Filter to remove insoluble impurities to obtain the supernatant of the second sample; adjust the acidity of the supernatant to make the pH of the supernatant < 2, and use the BaSO 4 coprecipitation method to coprecipitate radium to obtain a radium coprecipitate. The specific process is as follows:

[0102] 1) Add 5 ml of 20% sodium sulfate solution, add acetic acid to 0.4 mol / L, and keep stirring at 80 °C to 100 °C for 5 min to 20 min until the reaction is complete;

[0103] 2) After the reaction is complete and cooled to below 40 °C, gradually add 0.5 ml to 1 ml of 0.5% barium chloride dihydrate solution and observe the formation of the radium coprecipitate until the radium lithium ions in the supernatant are completely formed into the radium coprecipitate. During this process, ensure that the SO 4 2+ ions are in excess;

[0104] 3) Continue to cool for 10 min to 20 min until the mixed solution of the radium coprecipitate reaches room temperature, and centrifuge to collect the radium coprecipitate.

[0105] S6, Rinse the radium coprecipitate with deionized water multiple times to remove impurities and unreacted reagents in it;

[0106] S7, Use 50 ml to 80 ml of saturated Na 2 CO 3 solution to oscillate (stir) at 60 °C to 90 °C for 2 hours to 5 hours to convert the sulfate precipitate into a carbonate precipitate, with the aim of converting the sulfate precipitate that is difficult to dissolve in acid into a carbonate that is easy to dissolve in acid;

[0107] S8. Dissolve the carbonate precipitate completely with dilute nitric acid (1 mol / L - 2 mol / L) to obtain a mixed solution of radium coprecipitate;

[0108] S9. Separate Ra 2+ and Ba 2+ , and the specific process is as follows:

[0109] Adjust the acidity of the dilute nitric acid to 8 mol / L HNO 3 ;

[0110] After equilibrating the resin column with 8 mol / L HNO 3 solution, load the above-obtained mixed solution of radium coprecipitate onto the column, and elute with 4 - 6 times the column volume of 8 mol / L HNO 3 . Combine the effluent. Desorb Ba 3 with 0.01 mol / L HNO 2+ solution and regenerate the resin;

[0111] Evaporate the effluent of Ra 2+ to obtain relatively pure Ra(NO 3 ) 2 powder, and purify it with DGA resin, LN resin, etc. if necessary.

[0112] It should be noted that:

[0113] In S2 of this embodiment, the extraction solvent is turpentine, and its extraction time is 10 min - 30 min; among them, turpentine includes one of low-boiling organic solvents such as petroleum ether, ether, n-hexane, chloroform, gasoline, etc.

[0114] For samples with more insoluble organic matter, use alkaline substances such as sodium hydroxide (NaOH), potassium hydroxide (KOH), sodium borate (NaBO 3 )), potassium fluoride (KF), etc. to digest by high-temperature melting; dissolve the cooled melt block with 1 mol / L - 2 mol / L HCl solution, evaporate to near dryness, and then dissolve with dilute nitric acid (0.5 mol / L - 1 mol / L HNO 3 ). In S4 of this embodiment, sodium hydroxide (NaOH) is used for the digestion of the second sample.

[0115] Example Three

[0116] This embodiment provides a waste residue raw material using uranium ore tailings as the raw material for extracting radium ( 226 Ra), and obtains a scarce raw material for the production of medical isotopes from it. The specific process is as follows:

[0117] S1. Containing 226The waste residue sample of Ra (4.8 g) is crushed and ground to a particle size less than 80 mesh, dried at 80 °C to 150 °C for 120 to 240 min, and after complete drying, the first sample meeting the particle size requirements is obtained;

[0118] S2, Using a Soxhlet extraction device to remove petroleum substances in the first sample at 70 °C to 90 °C to obtain a second sample. The extraction solvent used in the Soxhlet extraction device is 20 ml to 40 ml of turpentine, and the extraction time is 10 min to 30 min;

[0119] S3, The sample after removing petroleum (i.e., the second sample) is vacuum dried at 150 °C to 250 °C for 60 min to 120 min to obtain a completely dry second sample;

[0120] S4, The completely dry second sample is digested by the HNO 3 +HF leaching method, evaporated to dryness after complete dissolution, and dissolved with 0.5 mol / L to 1 mol / L of HNO 3 solution;

[0121] S5, Filter to obtain the supernatant of the second sample solution, adjust the acidity of the supernatant to make the pH of the supernatant < 2, and use the BaSO 4 coprecipitation method to coprecipitate radium to obtain a radium coprecipitate. The specific process is as follows:

[0122] 1) Add 5 ml of 20% sodium sulfate solution, add acetic acid to 0.4 mol / L, and stir at 80 °C to 100 °C for 5 min to 20 min until the reaction is complete;

[0123] 2) After the reaction is complete, cool to below 40 °C, and gradually add 0.5 ml to 1 ml of 0.5% barium chloride dihydrate solution to observe the formation of the radium coprecipitate until the radium lithium ions in the supernatant are completely formed into the radium coprecipitate. During this process, ensure that the SO 4 2+ ions are in excess;

[0124] 3) Continue to cool for 10 min to 20 min until the mixture of the radium coprecipitate reaches room temperature, and centrifuge to collect the radium coprecipitate.

[0125] S6, Rinse the radium coprecipitate with deionized water multiple times to remove impurities and unreacted reagents;

[0126] S7, Use 50 ml to 80 ml of saturated Na 2 CO 3 solution to oscillate (stir) at 60 °C to 90 °C for 2 hours to 5 hours to convert the sulfate precipitate into a carbonate precipitate, with the aim of converting the sulfate precipitate that is difficult to dissolve in acid into a carbonate that is easy to dissolve in acid;

[0127] S8. Completely dissolve the carbonate precipitate with dilute nitric acid (1 mol / L - 2 mol / L) to obtain a mixed solution of radium coprecipitate;

[0128] S9. Separate Ra 2+ and Ba 2+ , specifically the process is as follows:

[0129] Adjust the acidity of the dilute nitric acid to 8 mol / L HNO 3 ;

[0130] After equilibrating the resin column with 8 mol / L HNO 3 solution, load the above-obtained mixed solution of radium coprecipitate onto the column, and elute with 4 to 6 times the column volume of 8 mol / L HNO 3 . Combine the effluent. Desorb Ba 3 with 0.01 mol / L HNO 2+ solution and regenerate the resin;

[0131] Evaporate to dryness the effluent of Ra 2+ to obtain relatively pure Ra(NO 3 ) 2 powder, and purify it with DGA resin, LN resin, etc. if necessary.

[0132] It should be noted that:

[0133] In S2 of this embodiment, the extraction solvent is turpentine, and the extraction time is 10 min - 30 min; among them, turpentine includes one of low-boiling organic solvents such as petroleum ether, ether, n-hexane, chloroform, gasoline, etc.

[0134] Example 4

[0135] This embodiment provides a waste residue raw material using phosphate ore slag as the extraction of radium ( 226 Ra), and obtains a scarce raw material for the production of medical isotopes from it. The specific process is as follows:

[0136] S1. Crush and grind the waste residue sample (5.8 g) containing 226 Ra to a particle size less than 80 mesh, and dry it at 80 °C - 150 °C for 120 - 240 min. After complete drying, obtain the first sample that meets the particle size requirements;

[0137] S2. Use a Soxhlet extraction device to remove petroleum substances in the first sample at 70 °C - 90 °C to obtain the second sample, where the extraction solvent used in the Soxhlet extraction device is 20 ml - 40 ml of turpentine, and the extraction time is 10 min - 30 min;

[0138] S3. Vacuum dry the sample without petroleum (i.e., the second sample) at 150 °C to 250 °C for 60 min to 120 min to obtain a completely dry second sample;

[0139] S4. Digest the completely dry second sample by NaOH melting. After the melt cools, completely dissolve it with 1 mol / L to 2 mol / L HCl solution, evaporate again until nearly dry, and dissolve it with 0.5 mol / L to 1 mol / L HNO 3 solution;

[0140] S5. Filter to obtain the supernatant of the second sample solution, adjust the acidity of the supernatant to make the pH of the supernatant < 2, and use the BaSO 4 coprecipitation method to coprecipitate radium to obtain a radium coprecipitate. The specific process is as follows:

[0141] 1) Add 5 mL of 20% sodium sulfate solution, add acetic acid to 0.4 mol / L, and keep stirring at 80 °C to 100 °C for 5 min to 20 min until the reaction is complete;

[0142] 2) After the reaction is complete, cool to below 40 °C, and gradually add 0.5 mL to 1 mL of 0.5% barium chloride dihydrate solution to observe the formation of the radium coprecipitate until the radium and lithium ions in the supernatant are completely formed into the radium coprecipitate. Ensure that the SO 4 2+ ions are in excess during this process;

[0143] 3) Continue to cool for 10 min to 20 min until the mixture of the radium coprecipitate reaches room temperature, and centrifuge to collect the radium coprecipitate.

[0144] S6. Rinse the radium coprecipitate with deionized water multiple times to remove impurities and unreacted reagents;

[0145] S7. Use 50 mL to 80 mL of saturated Na 2 CO 3 solution to oscillate (stir) at 60 °C to 90 °C for 2 hours to 5 hours to convert the sulfate precipitate into a carbonate precipitate, aiming to convert the sulfate precipitate that is difficult to dissolve in acid into a carbonate that is easy to dissolve in acid;

[0146] S8. Completely dissolve the carbonate precipitate with dilute nitric acid (1 mol / L to 2 mol / L) to obtain a mixture of the radium coprecipitate;

[0147] S9. Separate Ra 2+ and Ba 2+ using SR resin. The specific process is as follows:

[0148] Adjust the acidity of the dilute nitric acid to 8 mol / L HNO 3 ;

[0149] After equilibrizing the resin column with 8 mol / L HNO 3 solution, the above-obtained radium coprecipitate mixture was loaded onto the column, and eluted with 8 mol / L HNO 3 with a volume of 4 to 6 times the column volume, and the effluents were combined. Ba was desorbed with 0.01 mol / L HNO 3 solution and the resin was regenerated; 2+ The effluent of Ra was evaporated to dryness to obtain relatively pure Ra(NO

[0150] powder, and purified with DGA resin, LN resin, etc. if necessary. 2+ ) 3 ) 2 It should be noted that:

[0151] In S2 of this embodiment, the extraction solvent is turpentine, and the extraction time is 10 min to 30 min; among them, turpentine includes one of low-boiling organic solvents such as petroleum ether, diethyl ether, n-hexane, chloroform, gasoline, etc.

[0152] Example Five

[0153] This embodiment provides a waste residue raw material taking gas field waste residue as the extraction radium (

[0154] Ra), and obtaining the scarce raw materials for producing medical isotopes therefrom. The specific process is as follows: 226 S1, crushing and grinding the waste residue sample (4.2 g) containing

[0155] Ra to a particle size less than 80 mesh, drying at 80 °C to 150 °C for 120 to 240 min, and obtaining the first sample meeting the particle size requirements after complete drying; 226 Ra to a particle size less than 80 mesh, drying at 80 °C to 150 °C for 120 to 240 min, and obtaining the first sample meeting the particle size requirements after complete drying;

[0156] S2, removing petroleum substances in the first sample at 70 °C to 90 °C by using a Soxhlet extraction device to obtain the second sample, wherein the extraction solvent used in the Soxhlet extraction device is 20 ml to 40 ml of turpentine, and the extraction time is 10 min to 30 min;

[0157] S3, vacuum drying the sample after removing petroleum (i.e., the second sample) at 150 °C to 250 °C for 60 min to 120 min to obtain the completely dry second sample;

[0158] S4, digesting the completely dry second sample by the HNO 3 +HCl leaching method: slowly adding 100 ml of a mixed acid of concentrated HNO 3 with a volume ratio of 1:3 and concentrated HCl to the second sample, continuously stirring at 80 °C to 90 °C for 1 to 2 hours, and filtering the solid residue with 50 ml of 8 mol / L HNO 3The solution is continuously stirred at 80 °C to 90 °C for two - stage leaching for 1 hour. After filtration, the two supernatant liquids are combined. The supernatant liquid is evaporated to dryness, and the residue is dissolved with 0.5 mol / L to 1 mol / L HNO 3 solution;

[0159] S5. After filtration, the supernatant liquid of the second sample solution is obtained. The acidity of the supernatant liquid is adjusted to make the pH of the supernatant liquid < 2. The radium is coprecipitated by the BaSO 4 coprecipitation method to obtain radium coprecipitate. The specific process is as follows:

[0160] 1) Add 5 mL of 20% sodium sulfate solution, add acetic acid to 0.4 mol / L, and keep stirring at 80 °C to 100 °C for 5 min to 20 min until the reaction is complete;

[0161] 2) After the reaction is complete and cooled to below 40 °C, 0.5 mL to 1 mL of 0.5% barium chloride dihydrate solution is added dropwise while observing the formation of radium coprecipitate until the radium and lithium ions in the supernatant liquid are completely formed into radium coprecipitate. During this process, ensure that the SO 4 2+ ions are in excess;

[0162] 3) Continue to cool for 10 min to 20 min until the mixture of radium coprecipitate reaches room temperature, and centrifuge to collect the radium coprecipitate.

[0163] S6. The radium coprecipitate is rinsed with deionized water multiple times to remove impurities and unreacted reagents;

[0164] S7. Use 50 mL to 80 mL of saturated Na 2 CO 3 solution to oscillate (stir) at 60 °C to 90 °C for 2 hours to 5 hours to convert the sulfate precipitate into a carbonate precipitate. The purpose is to convert the sulfate precipitate that is difficult to dissolve in acid into a carbonate that is easy to dissolve in acid;

[0165] S8. The carbonate precipitate is completely dissolved with dilute nitric acid (1 mol / L to 2 mol / L) to obtain a mixture of radium coprecipitate;

[0166] S9. The SR resin is used to separate Ra 2+ and Ba 2+ , and the specific process is as follows:

[0167] Adjust the acidity of the dilute nitric acid to 8 mol / L HNO 3 ;

[0168] After the resin column is equilibrated with 8 mol / L HNO 3 solution, the above - obtained mixture of radium coprecipitate is loaded onto the column, and 4 to 6 times the column volume of 8 mol / L HNO 3Elute and combine the effluent. Desorb Ba with 0.01mol / L HNO 3 solution and regenerate the resin; 2+

[0169] Evaporate the effluent of Ra 2+ to obtain relatively pure Ra(NO 3 ) 2 powder, and purify it with DGA resin, LN resin, etc. if necessary.

[0170] It should be noted that:

[0171] In S2 of this embodiment, the extraction solvent is turpentine, and the extraction time is 10 min to 30 min; among them, turpentine includes one of low-boiling organic solvents such as petroleum ether, diethyl ether, n-hexane, chloroform, gasoline, etc.

[0172] Example VI

[0173] This embodiment provides a waste residue raw material using saline-alkali soil as the raw material for extracting radium ( 226 Ra), and obtains a scarce raw material for producing medical isotopes from it. The specific process is as follows:

[0174] S1, pulverize and grind a gas field waste residue sample (4.9 g) containing 226 Ra to a particle size less than 80 mesh, dry it at 80°C to 150°C for 120 min to 240 min, and obtain a first sample that meets the particle size requirements after complete drying;

[0175] S2, use a Soxhlet extraction device to remove petroleum substances in the first sample at 70°C to 90°C to obtain a second sample, where the extraction solvent used in the Soxhlet extraction device is 20 ml to 40 ml of turpentine, and the extraction time is 10 min to 30 min;

[0176] S3, vacuum dry the sample without petroleum (i.e., the second sample) at 150°C to 250°C for 60 min to 120 min to obtain a completely dry second sample;

[0177] S4, digest the completely dry second sample by NaBO 3 fusion method, and dissolve the melt block with 0.5mol / L to 1mol / L HNO 3 solution after cooling;

[0178] S5, filter the second sample solution to obtain the supernatant of the second sample solution, adjust the acidity of the supernatant to make the pH of the supernatant < 2, and use the BaSO 4 coprecipitation method to coprecipitate radium to obtain a radium coprecipitate. The specific process is as follows:

[0179] ​1) Add 5 mL of 20% sodium sulfate solution, add acetic acid until it reaches 0.4 mol / L, and stir at 80 °C to 100 °C for 5 min to 20 min until the reaction is complete;

[0180] 2) After the reaction is complete, cool it to below 40 °C, and gradually add 0.5 mL to 1 mL of 0.5% barium chloride dihydrate solution while observing the formation of radium coprecipitate until the radium and lithium ions in the supernatant are completely formed into radium coprecipitate. Ensure an excess of SO 4 2+ ions during this process;

[0181] 3) Continue to cool for 10 min to 20 min until the mixed solution of radium coprecipitate reaches room temperature, and centrifuge to collect the radium coprecipitate.

[0182] S6. Rinse the radium coprecipitate with deionized water multiple times to remove impurities and unreacted reagents;

[0183] S7. Oscillate (stir) with 50 mL to 80 mL of saturated Na 2 CO 3 solution at 60 °C to 90 °C for 2 hours to 5 hours to convert the sulfate precipitate into a carbonate precipitate, aiming to convert the sulfate precipitate that is difficult to dissolve in acid into a carbonate that is easily soluble in acid;

[0184] S8. Completely dissolve the carbonate precipitate with dilute nitric acid (1 mol / L to 2 mol / L) to obtain a mixed solution of radium coprecipitate;

[0185] S9. Separate Ra 2+ and Ba 2+ , and the specific process is as follows:

[0186] Adjust the acidity of the dilute nitric acid to 8 mol / L HNO 3 ;

[0187] After equilibrating the resin column with 8 mol / L HNO 3 solution, load the above-obtained mixed solution of radium coprecipitate onto the column, and elute with 4 to 6 column volumes of 8 mol / L HNO 3 . Combine the effluent. Desorb Ba 3 with 0.01 mol / L HNO 2+ solution and regenerate the resin;

[0188] Evaporate to dryness the effluent of Ra 2+ to obtain relatively pure Ra(NO 3 ) 2 powder, and purify it with DGA resin, LN resin, etc. if necessary.

[0189] It should be noted that:

[0190] In S2 of this embodiment, the extraction solvent is turpentine, and the extraction time is 10 min to 30 min; among them, turpentine includes one of low-boiling organic solvents such as petroleum ether, diethyl ether, n-hexane, chloroform, gasoline, etc.

[0191] In the above Examples 1 to 6, the acidity of the filtered supernatant was adjusted to pH < 2, which was to create a suitable chemical environment for the subsequent coprecipitation reaction. A lower value could inhibit some side reactions that might interfere with the precipitation reaction, and at the same time, it could also make the ionic form in the solution more conducive to the coprecipitation process with radium.

[0192] In S5, 5 mL of 20% sodium sulfate solution was added, which was a key step to provide ions. Ions are an important part of forming the precipitate, and they combine with the ions added subsequently to form, and radium ions will be coprecipitated during the formation of the precipitate.

[0193] Acetic acid was added to 0.4 mol / L. The main function of acetic acid was to adjust and maintain the acidity and ionic strength of the solution. It could make the chemical environment of the solution more stable, help control the rate of the precipitation reaction and the morphology of the precipitate, and ensure the smooth progress of the coprecipitation process.

[0194] Stir at 80 °C to 100 °C for 5 min to 20 min. Heating and stirring could accelerate the movement and reaction rate of ions, make ions fully mixed and react with other ions in the solution, promote the formation of the precipitate, and at the same time, it was also beneficial for radium ions to better enter the precipitate lattice to achieve coprecipitation.

[0195] After cooling to 40 °C, 0.5 mL to 1 mL of 0.5% barium chloride dihydrate solution was added dropwise to observe the formation of the precipitate. Cooling the solution could reduce the reaction rate, make the precipitation process slower and more orderly, be beneficial to form precipitates with larger particles and more complete structures, and facilitate subsequent separation and collection. Adding the barium chloride solution dropwise was to precisely control the amount of ions added, and at the same time observe the formation of the precipitate, and ensure that SO 4 2+ ions were in excess, make the ions react completely, increase the yield and purity of the precipitate, and thus improve the coprecipitation effect of radium.

[0196] Continue to cool and centrifuge to collect the precipitate: continue to cool for 10 min to 20 min to further grow and stabilize the precipitate particles, and then separate the precipitate from the solution by centrifugation. The centrifugal force could make the precipitate quickly settle to the bottom of the centrifuge tube, thus achieving effective separation of the precipitate and the supernatant to obtain the precipitate containing radium.

[0197] The radium recovery rate and radium purity obtained by separating and extracting from the waste residue using the method described in this application are described below through the following comparative examples.

[0198] The results of the radium recovery rate and radium purity finally obtained in the comparative example and the above-mentioned examples are shown in the following table:

[0199] Table of radium recovery rate and radium purity finally obtained in the comparative example and the above-mentioned examples

[0200] Number Sample type Sample mass / g Digestion method Radium recovery rate Radium purity Example 1 Residual scale of production tubing 4.6 <![CDATA[HNO 3 + HF acid dissolution]]> 95％ 99％ Example 2 Residual scale of production tubing 5.3 NaOH fusion 95％ 98.5％ Example 3 Uranium mine tailings 4.8 <![CDATA[HNO 3 + HF leaching]]> 88％ 98.8％ Example 4 Phosphate ore slag 5.8 NaOH fusion 91％ 98.1％ Example 5 Gas field waste residue 4.2 <![CDATA[HNO 3 +HCl leaching]]> 87％ 97.8％ Example 6 Gas field waste residue 4.9 <![CDATA[NaBO 3 molten]]> 94％ 99.1％

[0201] It can be seen from the above results that by using the method described in the present application, the recovery rate of the obtained radium is between 87% and 95%, and its purity is greater than 97.5%; and the above results show that the method described in the present application can extract and separate radium in different samples, and this method covers a wide range of sample types.

Claims

1. A method for separating and purifying waste residue 226 Ra method, characterized in that The method comprises the following steps: S1, for 226 The waste residue of Ra is pretreated to obtain a first sample with a particle size meeting the requirements; S2, removing petroleum substances from the first sample to obtain a second sample; S3, digesting and filtering the second sample to obtain a supernatant of the second sample; S4, obtaining a radium co-precipitate in the supernatant of the second sample by a sulfate co-precipitation method, and removing impurities; S5, purifying the radium co-precipitate after impurities are removed to obtain a radium co-precipitate mixed solution; S6, using SR resin to separate Ra from the radium co-precipitate mixture 2+ and Ba 2+ ; S7, Ra after purification and separation 2+ , and the final product is obtained.

2. A method for separating and purifying waste residue according to claim 1 226 Ra method, characterized in that The petroleum substances in S2 are removed by extraction, wherein the oil removal extractant is a low boiling point organic solvent that can dissolve or extract the petroleum substances.

3. A method for separating and purifying waste residue according to claim 1 226 Ra method, characterized in that The digestion method in S3 includes any one of mixed acid dissolution, mixed acid leaching and alkaline melting.

4. A method for separating and purifying waste residue according to claim 3 226 Ra method, characterized in that The mixed acid digestion includes any one of HNO3+HF dissolution or HNO3+HCl dissolution.

5. A method for separating and purifying waste residue according to claim 3 226 Ra method, characterized in that The mixed acid leaching includes any one of HNO3+HF leaching, HNO3+HCl leaching, and HNO3 leaching, wherein the mixed acid concentration used in the mixed acid leaching is 6 mol / L to 10 mol / L.

6. A method for separating and purifying waste residue according to claim 3 226 Ra method, characterized in that The alkaline substance in the alkaline melting includes any one of sodium hydroxide, potassium hydroxide, sodium borate and potassium fluoride.

7. A method for separating and purifying waste residue according to claim 1 226 Ra method, characterized in that The specific process of obtaining radium co-precipitate in S4 is: 1) Adjust the pH of the supernatant to <2; 2) Add sulfate and acetic acid to the supernatant with pH < 2, and obtain a mixed product after sufficient reaction. 3) After the mixed product is cooled to 40° C., 0.5% barium chloride dihydrate solution is added dropwise until the radium and lithium ions in the supernatant completely form a radium coprecipitate; 4) Continue cooling the mixed solution of the radium co-precipitate to room temperature and collect the radium co-precipitate by centrifugation.

8. A method for separating and purifying waste residue according to claim 1 226 Ra method, characterized in that The purification process of the radium coprecipitate after impurity removal in S5 is: 1) adding a carbonate solution to the radium co-precipitate after impurities are removed to convert the sulfate precipitate in the radium co-precipitate into a carbonate precipitate to obtain a mixture; 2) adding an acidic solution to the mixture to completely dissolve the precipitate in the mixture to obtain a pure solution; The carbonate includes any one of Na2CO3, K2CO3 and other inorganic or organic acid salts that achieve conversion using solubility product differences.

9. A method for separating and purifying waste residue according to claim 1 226 Ra method, characterized in that The purification in S6 was performed by resin extraction chromatography.