A method for concentrating radionuclides radium from the water

 

The invention relates to analytical chemistry of radioactive elements, and in particular to methods of radionuclides concentration with simultaneous separation of them. The method can be used for separation of radionuclides from large volumes of water in the natural environment. The technical result consists in developing a method of concentration of radionuclides radium-226 and radium-228 in the form of chromates and highlight them with subsequent translation into a soluble state. The method of concentration of radionuclides is that of a large volume of water containing radium-226 and radium-228, Coosada chromates of barium and radium by adding saturated solutions BaCl2To2Cr2About7and CH3The Na. The precipitate chromium, radium and barium filtered, washed, dried, calcined. To the resulting precipitate add anhydrous Na2CO3and K2CO3and melted in a muffle furnace until the mixture is homogenous. For transfer of radionuclides in solution alloy is leached, filtered, washed. The washed precipitate is dissolved in hot 5% Hcl, resulting radium-226 and radium-228 into solution. table 1.

The invention relates to analytical chemistry radioactive Alamosa can be used for isolation of radium-226 and radium-228 from large volumes of water in the natural environment.

A known method of separation of radium from water [C. M. Vdovenko, Y. C. Dubasov. Analytical chemistry of radium. - L.: Publishing House "Nauka", Leningrad. div., 1973 - S. 160-161]. The method consists in the measurement of the alpha-activity of radium, soosazhdenie with sulfate. From the water radium concentrated by coprecipitation with a mixture of two media - sulphates of barium and lead. Lead and barium is added to the alkaline solution containing citric acid, which prevents the formation of sludge even in the presence of sulfa-ions, which are often found in different waters. Quantitative precipitation of radium with native produce sulfuric acid. For the purification of radium from alpha-emitting natural isotopes spend pereosazhdeniya barium sulfate from a solution of EDTA. From EDTA barium sulfate periostat by adding acetic acid, the resulting precipitate almost captures uranium, thorium and lead.

There is a method of quantitative precipitation of radium with calcium carbonate [C. M. Vdovenko, Y. C. Dubasov. Analytical chemistry of radium. - L.: Publishing House "Nauka", Leningrad. div., 1973. - S. 160-161]. Analyzed water acidified to destruction of hydrocarbons that may contribute to partial dissolution of radium. In the sample add a saturated solution of chloride to the solution add 0.2 g of activated charcoal. The precipitate is filtered off after 3 hours, followed by the dissolution and determination of radium emanating method.

Closest to the claimed method is the determination of radium-226 in natural waters, which includes the concentration of radium-226 by coprecipitation of radium-226 with barium sulphate by heating [C. M. Vdovenko, Y. C. Dubasov. Analytical chemistry of radium. - L.: Publishing House "Nauka", Leningrad. div., 1973. - S. 160-161] . The method consists in the preliminary evaporation source acidified solution to 300-400 ml, deposition of radium-226 with barium sulphate by adding to a hot solution of 0.1 g of barium chloride and sulfuric acid (1: 5) followed by boiling and keeping warm for 3 hours Then the solution with the precipitate left for another night. Next, the precipitate is filtered off, washed, calcined and melted with a 6-7-fold amount of sodium carbonate (soda). The resulting alloy is dissolved and radium-226 define emanating method.

However, this method has several disadvantages. The method allows you to concentrate only radium-226 and chemical output is about 83%, requires a lot of time for analysis, because it includes a preliminary evaporation source solution. All stages of the method can retrogradely.

The present invention is to develop a fast enough method the concentration of radium-226 and radium-228 from large volumes of water with the main stages of the method in natural conditions with simultaneous separation of radionuclides and subsequent transfer them in a soluble state.

The technical result of the present invention is to increase the release of radionuclides.

The technical result is achieved by the method of concentration of radionuclides radium from the water, including coprecipitation of radionuclides in the presence of barium chloride, filtration, washing, calcining the precipitate and fusion with sodium carbonate, characterized in that the coprecipitation of radionuclides is carried out in the form of chromates by successive addition to 8-10 liters of water saturated solutions of barium chloride in 2 ml of potassium bichromate in 20 ml and sodium acetate in a quantity of 30 ml, and the injection of the sludge is carried out with 4 g of sodium carbonate with the addition of 2 g of potassium carbonate.

In the basis of the method based on the reaction of the simultaneous precipitation of radium with barium chromate (BaCrO4): BaCl2+ C2CR2About7+ H2O --> BaCrO4+ H2SGAs4+ 2KCl. Chromate is shoesadidas.

The method is as follows. In a large volume of water (8-10 l) sequentially add saturated solution of barium chloride (l2) in an amount of 2 ml, of bichromate of potassium (K2CR2About7) in 20 ml of acetic acid sodium (CH3The N) in an amount of 30 ml of the Latter to decrease the solubility of chromium, radium. The solution was incubated for 10-12 hours. The precipitate chromium, radium and barium filtered, washed, dried and calcined. To the resulting precipitate add sodium carbonate (Na2CO3) in an amount of 4 g, potassium carbonate (K2CO3) in an amount of 2 g and alloys. For the further transfer of radium-226 and radium-228 in the solution alloy is leached, filtered, washed. The washed precipitate is dissolved in hot 5% HCl, the radium-226 and radium-228 into solution.

Example. In the capacity of 8-10 l (plastic bucket) with water containing radionuclides (radium-226 and radium-228), with vigorous stirring successively added 2 ml of saturated solution l220 ml of a saturated solution of K2CR2About7and 30 ml of a saturated solution of CH3The ON. After keeping for 10-12 hours the precipitate chromium, radium and barium filtered through FSA distilled water. Plastic bucket that was settling, wiped with filter paper, which added to the precipitate of chromates. The precipitate is dried in air, placed in the tracing paper and transported to the laboratory. Then the precipitate together with a filter paper placed in a platinum crucible and calcined in a muffle furnace at a temperature of 800oC for 1 h Calcined residue triturated in a mortar with a glass pestle, add 4 g of anhydrous PA2CO3and 2 g2CO3and melted in a muffle furnace until a homogeneous composition at the same temperature. The residue from the crucible leached with hot distilled water, filtered through a filter of "blue ribbon" diameter 12.5 cm, 3 times washed with a hot solution of 5% Na2CO3then with distilled water. The washed precipitate is dissolved on the filter with hot 5% HCl, the radium-226 and radium-228 into solution. Analysis of samples with known concentrations of radionuclides showed that the chemical output when the level of confidence (P) 95% 93.866.48% (table).

The method is convenient for the concentration of radionuclides in the form of chromates with simultaneous separation of them from large volumes of water out of the laboratory (p the condition and analytical determination of radium-226 and radium-228 (I. E. The old man. Fundamentals of radiochemistry. L., 1969. - 247 S.; Methodological recommendations on sanitary control over the content of radioactive substances in the external environment. M., 1980. -336 C.) are carried out in laboratory conditions.

Claims

A method for concentrating radionuclides from water, including coprecipitation of radionuclides in the presence of barium chloride, filtration, washing, calcining the precipitate and fusion with sodium carbonate, characterized in that the deposition of radionuclides in the form of chromates perform sequential addition of 8-10 liters of water saturated solutions of barium chloride (l2) in an amount of 2 ml, of bichromate of potassium (K2CR2About7) in 20 ml of acetic acid sodium (CH3COONa) in an amount of 30 ml, the fusion of the resulting sludge is carried out with 4 g of sodium carbonate (PA2CO3) and 2 g of potassium carbonate (K2CO3).

 

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