阅读说明：本技术 一种检测稀土废水中锕-227分离程度的方法 (Method for detecting separation degree of actinium-227 in rare earth wastewater ) 是由 张魁芳 刘志强 朱薇 曹洪杨 于 2021-08-19 设计创作，主要内容包括：本发明公开了一种检测稀土废水中锕-227分离程度的方法。该方法,包括如下步骤：取稀土废水加入氧化钙或氢氧化钙调整稀土废水溶液的pH为6.0,测量上清液钙离子浓度记为W-(1)；过滤分离滤渣后,再向调整pH值后的稀土废水溶液中加入可溶性碳酸盐,沉淀分离稀土废水溶液中钙离子和锕-227离子,调整稀土废水溶液的pH为7.0～10.0,测量上清液钙离子浓度记为W-(2),并计算稀土废水溶液中钙离子分离率为：W-(1)-W-(2)/W-(1)×100％,以钙离子分离率评价稀土废水溶液中锕-227的分离率。本发明通过利用钙离子与锕-227离子沉淀分离过程性能相似的特点,采用钙离子的分离率评价锕-227离子的分离率。(The invention discloses a method for detecting the separation degree of actinium-227 in rare earth wastewater. The method comprises the following steps: adding calcium oxide or calcium hydroxide into the rare earth wastewater to adjust the pH value of the rare earth wastewater solution to 6.0, and recording the concentration of calcium ions in the supernatant as W 1 (ii) a Filtering and separating filter residues, adding soluble carbonate into the rare earth wastewater solution with the adjusted pH value, precipitating and separating calcium ions and actinium-227 ions in the rare earth wastewater solution, adjusting the pH value of the rare earth wastewater solution to 7.0-10.0, and measuring the concentration of the calcium ions in the supernatant and recording as W 2 And calculating the calcium ion separation rate in the rare earth wastewater solution as follows: w 1 ‑W 2 /W 1 X 100%, and evaluating the separation rate of actinium-227 in the rare earth wastewater solution by using the separation rate of calcium ions. The invention utilizes the performance of the precipitation separation process of calcium ions and actinium-227 ionsSimilarly, the separation rate of the actinium-227 ions is evaluated by the separation rate of calcium ions.)

1. A method for detecting the separation degree of actinium-227 in rare earth wastewater is characterized by comprising the following steps: adding calcium oxide or calcium hydroxide into the rare earth wastewater for blendingThe pH value of the whole rare earth wastewater solution is 6.0, and the concentration of calcium ions in the supernatant fluid is recorded as W₁(ii) a Filtering and separating filter residues, adding soluble carbonate into the rare earth wastewater solution with the adjusted pH value, precipitating and separating calcium ions and actinium-227 ions in the rare earth wastewater solution, adjusting the pH value of the rare earth wastewater solution to 7.0-10.0, and measuring the concentration of the calcium ions in the supernatant and recording as W₂And calculating the calcium ion separation rate in the rare earth wastewater solution as follows: w₁-W₂/W₁X 100%, and evaluating the separation rate of actinium-227 in the rare earth wastewater solution by using the separation rate of calcium ions.

2. The method for detecting the separation degree of actinium-227 in the rare earth wastewater according to claim 1, wherein the rare earth wastewater is rare earth wastewater containing actinium-227, the total alpha concentration is 100-31000 Bq/L, and the total beta concentration is 100-6100 Bq/L.

3. The method for detecting the separation degree of actinium-227 in rare earth wastewater according to claim 1, wherein the soluble carbonate is sodium carbonate.

Technical Field

The invention relates to the technical field of hydrometallurgy, in particular to a method for detecting the separation degree of actinium-227 in rare earth wastewater.

Background

The south ionic rare earth contains a certain amount of actinium-227, the actinium-227 is a daughter of uranium-235, belongs to extremely toxic natural radionuclide, and the relative risk of inhaling an alpha radiator is far higher than that of inhaling the radium-226. Along with the separation and extraction of rare earth products by south ionic rare earth enterprises, a considerable part of actinium-227 enters rare earth wastewater, so that the pollution is serious and the separation is required.

The direct actinium-227 measuring method includes radiochemical analysis method, alpha energy spectrum and HPGe-gamma spectrum, etc. these methods are expensive in apparatus and equipment and high in professional property, and the rare earth enterprise has no such equipment and operation condition. At present, rare earth enterprises mainly determine the total alpha and total beta sum of the rare earth enterprises by simply adopting low-background alpha and beta measuring instruments to indirectly judge the concentration of actinium-227. However, studies have found that the actinium-227 radioactivity just entering the wastewater can be very low as the parent uranium-235 is isolated and removed during the extraction process, but increases significantly after a period of standing, reaching a 99.2% equilibrium only after about 140 days (actinium 7 half-lives), and can increase by hundreds of times. For this reason, only the total alpha and total beta data measured after resting for equilibrium (around 140 days) can reflect the true level of actinium-227 concentration.

Based on the characteristics, in the actual production of rare earth enterprises, the real separation degree of actinium-227 in the precipitation separation process in wastewater cannot be quickly and accurately reflected, so that the radioactivity of the wastewater is difficult to control and exceeds the standard seriously, and huge pressure is brought to the environment. Therefore, a method for rapidly detecting the separation degree of actinium-227 in the rare earth wastewater is urgently needed.

Disclosure of Invention

The invention solves the problems in the prior art, and aims to provide a method for detecting the separation degree of actinium-227 in rare earth wastewater, so that the problem of overlong detection period of the separation degree of actinium-227 in the rare earth wastewater is solved.

In order to achieve the purpose, the invention adopts the technical scheme that: a method for detecting the separation degree of actinium-227 in rare earth wastewater comprises the following steps: adding calcium oxide or calcium hydroxide into rare earth wastewater to adjust the solubility of the rare earth wastewaterThe pH of the solution was 6.0, and the calcium ion concentration of the supernatant was measured and recorded as W₁(ii) a Filtering and separating filter residues, adding soluble carbonate into the rare earth wastewater solution with the adjusted pH value, precipitating and separating calcium ions and actinium-227 ions in the rare earth wastewater solution, adjusting the pH value of the rare earth wastewater solution to 7.0-10.0, and measuring the concentration of the calcium ions in the supernatant and recording as W₂And calculating the calcium ion separation rate in the rare earth wastewater solution as follows: w₁-W₂/W₁X 100%, and evaluating the separation rate of actinium-227 in the rare earth wastewater solution by using the separation rate of calcium ions.

Preferably, the rare earth wastewater is rare earth wastewater containing actine-227, the total alpha concentration is 100-31000 Bq/L, and the total beta concentration is 100-6100 Bq/L.

Preferably, the soluble carbonate is sodium carbonate.

Compared with the prior art, the invention has the beneficial effects that:

1. the method utilizes the characteristic that the performance of the precipitation separation process of calcium ions and actinium-227 ions is similar, adopts the calcium ions as reference elements, and evaluates the separation rate of the actinium-227 ions by the separation rate of calcium.

2. The method can calculate the actinium-227 separation degree immediately after the separation operation is finished, greatly shortens the detection time and can quickly judge the actinium-227 removal effect of the rare earth wastewater subjected to precipitation treatment compared with the conventional method of measuring the actinium-227 separation degree after the solution is placed for 140 days.

3. The method provided by the invention does not need expensive equipment, and has simple and convenient experiment and analysis processes and strong practicability.

Detailed Description

The following examples are further illustrative of the present invention and are not intended to be limiting thereof. The equipment and reagents used in the present invention are, unless otherwise specified, conventional commercial products in the art.

A method for detecting the separation degree of actinium-227 in rare earth wastewater comprises the following steps: adding calcium oxide or calcium hydroxide into the rare earth wastewater to adjust the pH value of the rare earth wastewater solution to 6.0, and recording the concentration of calcium ions in the supernatant as W₁(ii) a Filtering and separating filter residue, and adding the rare earth wastewater solution with the pH value adjustedAdding sodium carbonate, precipitating and separating calcium ions and actinium-227 ions in the rare earth wastewater solution, adjusting the pH value of the rare earth wastewater solution to 7.0-10.0, and measuring the concentration of the calcium ions in the supernatant and recording as W₂And calculating the calcium ion separation rate in the rare earth wastewater solution as follows: w₁-W₂/W₁X 100%, and evaluating the separation rate of actinium-227 in the rare earth wastewater solution by using the separation rate of calcium ions.

After the rare earth wastewater containing actinium-227 used in the following examples 1 to 4 and comparative examples 1 to 3 was left for 140 days, the total alpha concentration was 258Bq/L and the total beta concentration was 172 Bq/L.

Example 1

Adding calcium oxide into the rare earth wastewater to adjust the pH to 6.0, stirring for 30min, standing, and measuring the Ca ion concentration of the supernatant to be 3201 mg/L; after filtering and separating filter residues, adding calcium ions and actinium-227 ions in a sodium carbonate precipitation separation solution, adjusting the pH to 7.0, stirring for 30min, standing, measuring the concentration of Ca ions in a supernatant to be 316mg/L, calculating the separation rate of the Ca ions to be 90.13%, and according to the separation rate of the calcium ions, knowing that the separation rate of actinium-227 in the wastewater is about 90% and most of actinium-227 is separated.

Example 2

Adding calcium oxide into the rare earth wastewater to adjust the pH to 6.0, stirring for 30min, standing, and measuring the Ca ion concentration of the supernatant to be 3201 mg/L; after filtering and separating filter residues, adding sodium carbonate to precipitate calcium ions and actinium-227 ions in the separated solution, adjusting the pH to 8.0, stirring for 30min, standing, measuring the concentration of Ca ions in the supernatant to be 14.5mg/L, calculating the Ca ion separation rate to be 99.55%, and according to the calcium ion separation rate, knowing that the actinium-227 separation rate in the wastewater is close to 100%, almost completely separating.

Example 3

Adding calcium oxide into the rare earth wastewater to adjust the pH to 6.0, stirring for 30min, standing, and measuring the Ca ion concentration of the supernatant to be 3201 mg/L; after filtering and separating filter residues, adding sodium carbonate to precipitate calcium ions and actinium-227 ions in the separated solution, adjusting the pH to 9.0, stirring for 30min, standing, measuring the concentration of Ca ions in the supernatant to be 3.6mg/L, calculating the Ca ion separation rate to be 99.89%, and according to the calcium ion separation rate, knowing that the actinium-227 separation rate in the wastewater is close to 100%, almost completely separating.

Example 4

Adding calcium oxide into the rare earth wastewater to adjust the pH to 6.0, stirring for 30min, standing, and measuring the Ca ion concentration of the supernatant to be 3201 mg/L; after filtering and separating filter residues, adding sodium carbonate to precipitate calcium ions and actinium-227 ions in the separated solution, adjusting the pH to 10.0, stirring for 30min, standing, measuring the concentration of Ca ions in the supernatant to be 2.2mg/L, calculating the Ca ion separation rate to be 99.93%, and according to the calcium ion separation rate, knowing that the actinium-227 separation rate in the wastewater is close to 100%, almost completely separating.

The final supernatants obtained in examples 1-4 were left for 140 days, the total alpha concentration and the total beta concentration in the solution were measured and the actual actinide-227 separation rate was indirectly reflected as the actual (total alpha + total beta) separation rate, the resulting actinide-227 separation rate was compared with the calcium ion separation rate and the results were recorded in table 1. It can be seen that the actual actinide 227 separation rate is close to the Ca ion separation rate, and the actinide 227 separation rate can be rapidly evaluated by using the Ca ion separation rate.

TABLE 1 results of actinium-227 separation in examples 1-4 compared with results of calcium ion separation

Examples	1	2	3	4
					Total alpha concentration (Bq/L)	20.1	4.7	0.81	0.5
Total beta concentration (Bq/L)	12.6	1.68	1.02	0.68
					Actinium-227 separation (%)	92.39	98.52	99.57	99.73
Ca ion isolation (%)	90.13	99.55	99.89	99.93

Comparative example 1

Adding calcium oxide into the rare earth wastewater to adjust pH to 6.0, stirring for 30min, standing, and measuring the Ca ion concentration W of the supernatant₁3201 mg/L; filtering to separate residue, adding calcium oxide precipitate to separate calcium ion and actinium-227 ion, adjusting pH to 7.0, stirring for 30min, standing, and measuring supernatant Ca concentration W₂Is 3210 mg/L. Reference ion concentration W of calcium in the process₁、W₂Basically has no change, the actual separation rate of the actinium-227 is close to 80 percent, and the separation rate of calcium ions can not evaluate the separation rate of the actinium-227 in the rare earth wastewater solution.

Comparative example 2

Adding sodium carbonate into the rare earth wastewater to adjust the pH to 6.0, stirring for 30min, standing, and measuring the Ca ion concentration W of the supernatant₁(ii) a Filtering to separate residue, adding sodium carbonate to precipitate calcium ion and actinium-227 ion, adjusting pH to 7.0, stirring for 30min, standingStanding, measuring the concentration of Ca ion in the supernatant to W₂. No calcium reference ion W is introduced in the process₁、W₂The separation rate of the actual actinium-227 is more than 90 percent, and the separation rate of calcium ions can not evaluate the separation rate of actinium-227 in the rare earth wastewater solution.

Comparative example 3

Adding sodium carbonate into the rare earth wastewater to adjust the pH to 6.0, stirring for 30min, standing, and measuring the Ca ion concentration W of the supernatant₁(ii) a Filtering to separate residue, adding calcium ion and actinium-227 ion in calcium oxide precipitate separation solution, adjusting pH to 10.0, stirring for 30min, standing, and measuring supernatant Ca ion concentration W₂The concentration was 3258 mg/L. In the process of adding sodium carbonate, no calcium reference ion W is introduced₁Very low, W₂Much greater than W₁And the actual separation rate of actinium-227 is more than 80%, and the separation rate of calcium ions can not evaluate the separation rate of actinium-227 in the rare earth wastewater solution.

After the rare earth wastewater containing actinium-227 used in the following examples 5 to 8 and comparative examples 4 to 6 was left for 140 days, the total alpha concentration was 30514Bq/L and the total beta concentration was 6041 Bq/L.

Example 5

Adding calcium oxide into the rare earth wastewater to adjust the pH to 6.0, stirring for 30min, standing, and measuring the Ca ion concentration of the supernatant to be 3282 mg/L; after filtering and separating filter residues, adding calcium ions and actinium-227 ions in a sodium carbonate precipitation separation solution, adjusting the pH to 7.0, stirring for 30min, standing, measuring the concentration of Ca ions in a supernatant to be 408mg/L, calculating the separation rate of the Ca ions to be 87.57%, and according to the separation rate of the calcium ions, knowing that the separation rate of actinium-227 in the wastewater is about 90% and most of actinium-227 is separated.

Example 6

Adding calcium oxide into the rare earth wastewater to adjust the pH to 6.0, stirring for 30min, standing, and measuring the Ca ion concentration of the supernatant to be 3282 mg/L; after filtering and separating filter residues, adding sodium carbonate to precipitate calcium ions and actinium-227 ions in the separated solution, adjusting the pH to 8.0, stirring for 30min, standing, measuring the concentration of Ca ions in the supernatant fluid to be 38.1mg/L, calculating the Ca ion separation rate to be 98.84%, and according to the calcium ion separation rate, knowing that the actinium-227 separation rate in the wastewater is close to 100%, almost completely separating.

Example 7

Adding calcium oxide into the rare earth wastewater to adjust the pH to 6.0, stirring for 30min, standing, and measuring the Ca ion concentration of the supernatant to be 3282 mg/L; after filtering and separating filter residues, adding sodium carbonate to precipitate calcium ions and actinium-227 ions in the separated solution, adjusting the pH to 9.0, stirring for 30min, standing, measuring the concentration of Ca ions in the supernatant to be 9.5mg/L, calculating the Ca ion separation rate to be 99.71%, and according to the calcium ion separation rate, knowing that the actinium-227 separation rate in the wastewater is close to 100%, almost completely separating.

Example 8

Adding calcium oxide into the rare earth wastewater to adjust the pH to 6.0, stirring for 30min, standing, and measuring the Ca ion concentration of the supernatant to be 3282 mg/L; after filtering and separating filter residues, adding sodium carbonate to precipitate calcium ions and actinium-227 ions in the separated solution, adjusting the pH to 10.0, stirring for 30min, standing, measuring the concentration of Ca ions in the supernatant to be 12.8mg/L, calculating the Ca ion separation rate to be 99.61%, and according to the calcium ion separation rate, knowing that the actinium-227 separation rate in the wastewater is close to 100%, almost completely separating.

The final supernatants obtained in examples 5-8 were left for 140 days, the total alpha and beta concentrations in the solution were measured and the actual actinide 227 separation rate was reflected indirectly as the actual (total alpha + total beta) separation rate, the resulting actinide 227 separation rate was compared with the calcium ion separation rate and the results were recorded in table 2. It can be seen that the actual actinide 227 separation rate is close to the Ca ion separation rate, and the actinide 227 separation rate can be rapidly evaluated by using the Ca ion separation rate.

TABLE 2 results of actinide-227 separations compared with calcium ion separations in examples 5-8

Examples	5	6	7	8
					Total alpha concentration (Bq/L)	2245	651	210	159
Total beta concentration (Bq/L)	339	84.1	17.5	32.6
					Actinium-227 separation (%)	92.93	97.99	99.38	99.48
Ca ion isolation (%)	87.57	98.84	99.71	99.61

Comparative example 4

Adding calcium oxide into the rare earth wastewater to adjust pH to 6.0, stirring for 30min, standing, and measuring the Ca ion concentration W of the supernatant₁3282 mg/L; filtering to separate residue, adding calcium oxide precipitate to separate calcium ion and actinium-227 ion, adjusting pH to 7.0, stirring for 30min, standing, and measuring supernatant Ca ion concentration W₂Is 3285 mg/L. Reference ion concentration W of calcium in the process₁、W₂Basically has no change, the actual separation rate of the actinium-227 is close to 80 percent, and the separation rate of calcium ions can not evaluate the separation rate of the actinium-227 in the rare earth wastewater solution.

Comparative example 5

Adding sodium carbonate into the rare earth wastewater to adjust the pH to 6.0, stirring for 30min, standing, and measuring the Ca ion concentration W of the supernatant₁(ii) a Filtering to separate residue, adding sodium carbonate precipitate to separate calcium ion and actinium-227 ion, adjusting pH to 7.0, stirring for 30min, standing, and measuring Ca ion concentration W of supernatant₂. No calcium reference ion W is introduced in the process₁、W₂The separation rate of the actual actinium-227 is close to 90%, and the separation rate of calcium ions can not evaluate the separation rate of actinium-227 in the rare earth wastewater solution.

Comparative example 6

Adding sodium carbonate into the rare earth wastewater to adjust the pH to 6.0, stirring for 30min, standing, and measuring the Ca ion concentration W of the supernatant₁(ii) a Filtering to separate residue, adding calcium ion and actinium-227 ion in calcium oxide precipitate separation solution, adjusting pH to 10.0, stirring for 30min, standing, and measuring supernatant Ca ion concentration W₂The concentration was 3276 mg/L. In the process of adding sodium carbonate, no calcium reference ion W is introduced₁Very low, W₂Much greater than W₁And the actual separation rate of actinium-227 is more than 80%, and the separation rate of calcium ions can not evaluate the separation rate of actinium-227 in the rare earth wastewater solution.

The above is only a preferred embodiment of the present invention, and it should be noted that the above preferred embodiment should not be considered as limiting the present invention, and the protection scope of the present invention should be subject to the scope defined by the claims. It will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the spirit and scope of the invention, and these modifications and adaptations should be considered within the scope of the invention.