1. A method of identifying a favorable temperature range for enriching uranium for pH change, the method comprising the steps of:

collecting a granite type uranium ore sample, and pretreating the sample;

step (2), preparing a uranium-containing medium, and analyzing the uranium content of a uranium-containing solution;

step (3), carrying out experiments of pH value change and uranium enrichment precipitation under different temperature conditions;

and (4) determining that the dissolving capacity of uranium in the uranium-containing geological fluid is influenced by the change of the pH value at different temperatures, and determining the change range of the pH value which is beneficial to enriching uranium in the alkaline fluid under different temperature conditions.

2. The method for confirming the favorable temperature range of the uranium enriched with the pH change according to claim 1, wherein the pretreatment of the sample in the step (1) is specifically as follows: and crushing the sample to 40-60 meshes, ultrasonically cleaning for 10min, and drying for 6h in a 50 ℃ forced air drying oven.

3. A method of identifying a favorable temperature range for uranium enrichment by pH change according to claim 1, wherein step (2) comprises:

step (2.1), preparing a sample leaching solution;

step (2.2), leaching the sample by using a sample leaching solution to prepare a uranium-containing medium;

and (2.3) analyzing the uranium content of the uranium-containing solution by adopting a plasma mass spectrometer.

4. A method according to claim 3, wherein the leachate used in step (2.1) is deionized water and NaHCO₃Prepared NaHCO with mass fraction of 0.5%₃。

5. A method of identifying a favorable temperature range for uranium enrichment by pH change according to claim 3, wherein the step (2.2) is specifically: 0.5% NaHCO in normal temperature flow reaction device₃Leaching the experimental sample obtained in the step (1), setting the flow rate to be 0.2ml/min and the pressure to be 1atm, and carrying out 1-month experiment to obtain the uranium-containing medium.

6. A method of identifying a favorable temperature range for uranium enrichment by pH change according to claim 1, wherein step (3) comprises:

step (3.1), preparing a pH adjusting reagent;

adding pH adjusting reagents with different volumes into the uranium-containing medium to obtain uranium-containing media with different pH values;

step (3.3), carrying out different temperature experiments on uranium-containing media with different pH values;

and (3.4) analyzing the uranium content of the uranium-containing solution after the experiment, and determining the pH value of the uranium-containing medium after the experiment.

7. A method according to claim 6, wherein the pH adjusting reagent in step (3.1) is a hydrochloric acid solution prepared with a volume ratio of concentrated hydrochloric acid to deionized water of 1: 10.

8. A method of determining a favorable temperature range for uranium enrichment for pH changes according to claim 6, wherein step (3.2) uses a microsyringe to add the pH adjusting reagent.

9. A method of validating a favorable temperature range for enriching uranium with a change in pH according to claim 8, wherein the volumes of pH adjusting reagent added in step (3.2) are: to 20mL of the uranium-containing medium were added 0.9mL, 0.95mL, 1mL, 1.05mL, 1.1mL, 1.15mL, and 1.2mL of a pH adjusting reagent.

10. A method of validating a favorable temperature range for enriching uranium with pH value changes according to claim 6, wherein the experimental temperatures in step (3.3) are respectively: 80 deg.C, 100 deg.C, 120 deg.C, 140 deg.C, 150 deg.C.

11. A method of validating a favorable temperature range for enriching uranium with a change in pH according to claim 6, wherein the step (3.4) is specifically: and (4) carrying out centrifugal separation on the experimental medium obtained in the step (3.3), and taking the supernatant to carry out uranium content analysis and pH value determination.

12. A method of identifying a favorable temperature range for uranium enrichment by pH shift according to claim 11, wherein in step (3.4) the centrifugation rate is 10000r/min and the centrifugation time is 3 min.

Background

The reducing environment formed by Eh change is a key condition for ore formation of sandstone-type uranium ores, but the physical and chemical conditions are not changed independently, and the change of Eh is often accompanied by the change of pH value. Previous researches show that the change of the pH value is also an influence factor of uranium enrichment precipitation, but no relevant data exists on how the pH value changes and which interval changes at different temperatures to be beneficial to uranium enrichment precipitation.

Therefore, it is necessary to develop a quantitative simulation experiment method to determine the relationship between the pH value change at different temperatures and uranium enrichment precipitation in the geological fluid, so as to provide experimental data support for developing uranium mineralization theory.

Disclosure of Invention

The invention aims to provide a method for confirming a favorable temperature range of enriched uranium with pH value change, which determines the relationship between the pH value change at different temperatures and uranium enrichment precipitation in geological fluid through sample pretreatment, uranium-containing medium preparation, experiments on pH value change and uranium enrichment precipitation under different temperature conditions, medium analysis after the experiments and analysis data arrangement and interpretation.

The technical scheme for realizing the purpose of the invention is as follows: a method of identifying a favorable temperature range for enriching uranium for pH change, the method comprising the steps of:

collecting a granite type uranium ore sample, and pretreating the sample;

step (2), preparing a uranium-containing medium, and analyzing the uranium content of a uranium-containing solution;

step (3), carrying out experiments of pH value change and uranium enrichment precipitation under different temperature conditions;

and (4) determining that the dissolving capacity of uranium in the uranium-containing geological fluid is influenced by the change of the pH value at different temperatures, and determining the change range of the pH value which is beneficial to enriching uranium in the alkaline fluid under different temperature conditions.

Further, the pretreatment of the sample in the step (1) specifically comprises: and crushing the sample to 40-60 meshes, ultrasonically cleaning for 10min, and drying for 6h in a 50 ℃ forced air drying oven.

Further, the step (2) includes:

step (2.1), preparing a sample leaching solution;

step (2.2), leaching the sample by using a sample leaching solution to prepare a uranium-containing medium;

and (2.3) analyzing the uranium content of the uranium-containing solution by adopting a plasma mass spectrometer.

Further, the leaching solution in the step (2.1) adopts deionized water and NaHCO₃Prepared NaHCO with mass fraction of 0.5%₃。

Further, the step (2.2) is specifically: 0.5% NaHCO in normal temperature flow reaction device₃Leaching the experimental sample obtained in the step (1), setting the flow rate to be 0.2ml/min and the pressure to be 1atm, and carrying out 1-month experiment to obtain the uranium-containing medium.

Further, the step (3) includes:

step (3.1), preparing a pH adjusting reagent;

adding pH adjusting reagents with different volumes into the uranium-containing medium to obtain uranium-containing media with different pH values;

step (3.3), carrying out different temperature experiments on uranium-containing media with different pH values;

and (3.4) analyzing the uranium content of the uranium-containing solution after the experiment, and determining the pH value of the uranium-containing medium after the experiment.

Further, in the step (3.1), the pH adjusting reagent is a hydrochloric acid solution prepared by a volume ratio of concentrated hydrochloric acid to deionized water of 1: 10.

Further, in the step (3.2), a pH adjusting reagent is added by using a microsyringe.

Further, the volumes of the pH adjusting reagent added in the step (3.2) are respectively as follows: to 20mL of the uranium-containing medium were added 0.9mL, 0.95mL, 1mL, 1.05mL, 1.1mL, 1.15mL, and 1.2mL of a pH adjusting reagent.

Further, the experimental temperatures in the step (3.3) are respectively as follows: 80 deg.C, 100 deg.C, 120 deg.C, 140 deg.C, 150 deg.C.

Further, the step (3.4) is specifically: and (4) carrying out centrifugal separation on the experimental medium obtained in the step (3.3), and taking the supernatant to carry out uranium content analysis and pH value determination.

Further, in the step (3.4), the centrifugation speed is 10000r/min, and the centrifugation time is 3 min.

The invention has the beneficial technical effects that:

1. the method for confirming the favorable temperature range of the enriched uranium with the change of the pH value is simple and convenient to operate and high in operability;

2. according to the method for confirming the favorable temperature range of the enriched uranium with the pH value changing, the trace sample injector is adopted to control the amount of the pH adjusting reagent, so that the method has higher precision;

3. according to the method for confirming the favorable temperature range of the uranium enriched by changing the pH value, the pH value interval of the uranium-containing solution with the drastic change of the uranium concentration under different temperature conditions is obtained through a simulation experiment, the pH value range favorable for uranium enrichment precipitation under different temperatures is determined, so that the influence of the pH value on the uranium enrichment precipitation is changed from qualitative to quantitative, and one-hand experimental data support is provided for the deepening sandstone-type uranium ore formation theory.

Drawings

FIG. 1 is a graphical representation of uranium enrichment-pH-temperature relationship in accordance with the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

The invention provides a method for confirming a favorable temperature range for enriching uranium with pH value change, which comprises the following steps:

collecting a granite type uranium ore sample, and pretreating the sample

Collecting Guangxi Miao mountain sand river deposit granite type uranium ore samples, crushing to 40-60 meshes, ultrasonically cleaning for 10min, removing dust and burrs, improving sample uniformity, and drying in a 50 ℃ blast drying oven for 6h to serve as experimental samples for later use.

Step (2), preparing a uranium-containing medium, and analyzing the uranium content of a uranium-containing solution

Step (2.1), preparing a sample leaching solution

By using deionized water and NaHCO₃(AR) preparation of 0.5% NaHCO₃As the leachate of the experimental sample.

Step (2.2), leaching the sample by adopting the sample leaching solution to prepare a uranium-containing medium

0.5% NaHCO in normal temperature flow reaction device₃Leaching the experimental sample obtained in the step (1), setting the flow rate to be 0.2mL/min and the pressure to be 1atm, and carrying out 1-month experiment to obtain 8640mL of uranium-containing medium.

Step (2.3), the uranium content of the uranium-containing solution is analyzed by adopting a plasma mass spectrometer

According to the silicate rock chemical analysis method, Element XR plasma mass spectrometer is adopted to analyze the uranium concentration of the uranium-containing solution, and the uranium concentration in the uranium-containing solution is 172.18 multiplied by 10^-6(mass fraction).

Step (3) developing experiments of pH value change and uranium enrichment precipitation under different temperature conditions

Step (3.1), preparing pH regulating reagent

Deionized water and concentrated hydrochloric Acid (AR) are used for preparing hydrochloric acid with the volume ratio of 1:10 of the concentrated hydrochloric acid to the deionized water as a pH value adjusting reagent of a uranium-containing medium.

Step (3.2) of adding different volumes of pH adjusting reagents into the uranium-containing medium to obtain uranium-containing media with different pH values

And (3) respectively taking 5 parts of the uranium-containing medium obtained in the step (2.2), wherein the volume of each part of the uranium-containing medium is 20mL, and respectively adding 0.9mL, 0.95mL, 1mL, 1.05mL, 1.1mL, 1.15mL and 1.2mL of 1:10 hydrochloric acid pH adjusting reagents by using a microsyringe to change the pH value of the medium.

Step (3.3), carrying out different temperature experiments on uranium-containing media with different pH values

The sandstone-type uranium ore is generally low-temperature ore-forming, so the experimental temperature is selected to be 80 ℃, 100 ℃, 120 ℃, 140 ℃ and 150 ℃. According to the saturated vapor pressure parameter of the experimental medium, the experimental device is selected to be a 50mL hydrothermal kettle, and the lining is made of polytetrafluoroethylene. The experimental time was selected as a minimum equilibration time of 14 days for pH change and uranium enrichment.

Namely, the uranium-containing media with different pH values obtained in the step (2.2) are respectively added into a 50mL hydrothermal kettle, heated by an air-blast drying oven, and five different experimental temperatures of 80 ℃, 100 ℃, 120 ℃, 140 ℃ and 150 ℃ are sequentially selected, and the experimental time is 14 days.

Step (3.4), analyzing the uranium content of the uranium-containing solution after the experiment, and determining the pH value of the uranium-containing medium after the experiment

After the experiment is finished, quenching with cold water to quickly reduce the temperature, taking out the experiment medium, centrifuging for 3min in a 10000r/min centrifuge, and taking 15mL of supernatant.

The medium after the experiment is subjected to uranium concentration analysis by an Element XR plasma mass spectrometer according to an analysis method of DZ/T0064.80-1993, and the pH value of the medium after the experiment is tested by a Mettler-Toledo multi-parameter tester S400-K. The results of pH and uranium concentration in the uranium containing solution at different temperatures are shown in table 1.

TABLE 1 results of pH values and uranium concentrations in uranium-containing solutions at different temperatures

Step (4), determining that the dissolving capacity of uranium in the uranium-containing geological fluid is influenced by the change of pH value at different temperatures, and determining the change range of the pH value which is beneficial to enriching uranium in the alkaline fluid under different temperature conditions

Through the experimental data obtained in the table 1, the experiment is simulated by the relationship between the change of the pH value and the precipitation of uranium, the original experimental medium is uranyl carbonate solution, the pH value is 9.213, and the experiment is similar to the properties of geological fluid of sandstone uranium mineralization.

A graphical representation of uranium enrichment versus pH versus temperature is plotted against the data in table 1, as shown in fig. 1.

It can be seen from table 1 and fig. 1 that along with the decrease of the pH value to 6.404-8.895 and the temperature within the range of 120-150 ℃, uranium in the uranium-containing medium is significantly enriched, uranium precipitates are more obvious, and the enrichment rate is more than 90%. Under a certain pH condition, the uranium enrichment rate is increased along with the temperature rise, the pH value is in the range of 7.738-8.895, the uranium at 80 ℃ is relatively enriched (the enrichment rate is 6.67-48.54%), the uranium at 100 ℃ is easily enriched (the enrichment rate is 35.2-76.65%), and the uranium at 120-150 ℃ is significantly enriched (the enrichment rate is 92.07-99.34%).

Experiments show that when the weakly alkaline uranyl carbonate-containing geological fluid encounters acidic substances in the migration process, such as organic acid which is a decomposition product of organic substances, the pH value of the geological fluid evolves towards neutrality, and uranium enrichment precipitation is facilitated. Experiments prove that the pH value change is also an important influence factor of the enrichment of the alkaline geological fluid uranium besides being limited by a reduction environment in the ore forming process of the sandstone-type uranium ore.

The present invention has been described in detail with reference to the drawings and examples, but the present invention is not limited to the examples, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present invention. The prior art can be adopted in the content which is not described in detail in the invention.