CN102478674A - A Method for Tracing and Exploring Hydrothermal Uranium Deposits with Combination of Geochemical Elements - Google Patents

Abstract

The invention belongs to a uranium ore exploration method, and particularly discloses a method for combined tracing exploration of hydrothermal uranium ores by using geochemical elements, which comprises the following steps: measuring uranium components in soil of the exploration area; measuring²¹⁰Po; making a uranium component,²¹⁰A Po element plane contour map; judging whether the uranium caused by the ore is abnormal or not according to the ratio of the uranium component to the total uranium; if the uranium caused by the ore is abnormal, further judging: firstly, whether a uranium component abnormal concentration center exists is checked through a uranium component contour map; ② pass through²¹⁰Po contour map shows whether there is a uranium component,²¹⁰Po abnormal combination; whether the uranium component abnormal area corresponds to a composite section beneficial to the ore-forming fracture structure altered zone or not; and if at least 2 conclusions in the first step and the third step are positive, judging that the hydrothermal uranium ore exists. The method extracts and measures the uranium component of the surface soil sample,²¹⁰And Po, detecting hydrothermal uranium ore with the covering layer thickness of ten meters to hundreds of meters.

Description

A Method for Tracing and Exploring Hydrothermal Uranium Deposits with Combination of Geochemical Elements

technical field

The invention belongs to a method for prospecting uranium ore, in particular to a method for prospecting hydrothermal uranium ore through geochemical element combination tracing technology.

Background technique

After more than 50 years of uranium exploration work, most of the shallow deposits have been discovered. With the continuous deepening of the prospecting work, the prospecting depth is getting bigger and bigger, especially the prospecting depth of hydrothermal uranium ore is getting bigger and bigger. For a long time, conventional uranium ore geochemical prospecting (referred to as geochemical prospecting) methods at home and abroad mainly use the total amount of uranium and its associated elements to delineate the surface secondary dispersed halo, dispersed flow or The primary halo looks for outcrops, surface mines and shallow mines. However, since the secondary halos and primary halos generated by hydrothermal uranium deposits are covered by the overburden, and the thickness of the overburden is tens of meters or hundreds of meters, this total geochemical prospecting method is very convenient for the exploration of hydrothermal uranium deposits. powerless. Therefore, in order to make new progress in the exploration of hydrothermal uranium ore, it has become very difficult to continue or improve the conventional gross geochemical prospecting method. There is an urgent need for prospecting methods and technologies that can directly identify deep uranium mineralization from the surface.

Contents of the invention

The purpose of the present invention is to provide a method for tracing and prospecting hydrothermal uranium ore by combination of geochemical elements, which can effectively solve the key problem that conventional total geochemical prospecting methods cannot detect deep hydrothermal uranium ore.

The technical solution for realizing the object of the present invention: a method for trace exploration of hydrothermal uranium ore by combination of geochemical elements, which comprises the following steps:

(1) Soil sample collection and processing

Select sampling points in the survey area with a certain sampling density, and collect a certain quality of soil at the top of layer B at each sampling point;

(2) Measure the uranium content in the soil of the exploration area

(2.1) Extraction of uranium content

Get a certain amount of soil at the top of the B layer in the above step (1) and place it in a container, and add a mixed solution of ammonium citrate and ammonium carbonate to the container, stir and filter after placing, the filtrate is accepted by the first colorimetric tube, and the Rinse the filtrate in the first colorimetric tube with deionized water and shake well; extract a certain volume of filtrate rinsed with deionized water, place it in the second colorimetric tube, and pour it into the second colorimetric tube Add nitric acid solution, rinse with deionized water and shake well;

(2.2) Determination of uranium content

Determination of the uranium content of the solution flushed with deionized water in the second colorimetric tube of the above step (2.1), promptly obtains the uranium content of the sampling point;

(3) Measure ²¹⁰ Po

(3.1) Extraction of ²¹⁰ Po

Get a certain amount of soil at the top of the B layer in the above-mentioned steps (1) and place it in a container, and add hydrochloric acid to the container, then put into the red copper sheet that has been treated with nitric acid; Oscillate, at this time ²¹⁰ Po is enriched on the copper sheet, take out the round copper sheet;

(3.2) Determination of ²¹⁰ Po

Measure the α-ray intensity of the copper sheet to obtain the content of ²¹⁰ Po in the soil;

(4) Make plane contour maps of uranium content and ²¹⁰ Po elements

According to the measurement results of the above steps (2) and (3), a uranium component contour map and a ²¹⁰ Po element plane contour map are produced, and the mineralization prospect area is preliminarily circled;

(5) Determine whether there are hydrothermal uranium deposits in the exploration area through the identification of ore-induced anomalies

(5.1) According to the ratio of uranium content/total uranium content, it is judged whether it is abnormal mineral-induced uranium content

If the ratio of uranium content/total uranium is greater than or equal to 0.1, it is an abnormality of uranium content caused by ore; if the ratio of uranium content/total uranium is less than 0.1, it is an anomaly of non-mineral uranium content;

(5.2) If it is anomalous uranium content caused by ore, it is further inferred whether there is a hydrothermal uranium deposit in the exploration area based on the following conditions:

① Through the contour map of uranium content, whether there is an anomalous distribution pattern of overlapping and gradually enriched uranium content and a strong uranium content anomalous concentration center, that is, the uranium content gradually increases from the outer zone to the middle zone, and then to the inner zone. high area;

② Through the ²¹⁰ Po contour map, check whether there is a combination of uranium content and ²¹⁰ Po anomaly, that is, whether the corresponding anomalous areas basically overlap;

③Whether the uranium component anomalous area corresponds to the favorable ore-forming fault structural alteration zone is a composite section, that is, the anomalous area is superimposed on the geological map of the area to see whether the ore-forming fault structural alteration zone passes through the anomalous area.

If at least two of the inference conclusions of steps ①-③ in the above step (5.2) are affirmative, it can be determined that there are hydrothermal uranium deposits in the exploration area; otherwise, there is no hydrothermal uranium deposit in the exploration area.

Described step (1) specifically comprises the following steps:

(1.1) Select sampling points in the survey area with a certain sampling density;

(1.2) Collect a certain quality of soil at the top of layer B at each sampling point, sieve the collected soil at the top of layer B, and get a certain quality of soil after sieving at each sampling point, first dry and then cool to room temperature Backup.

The sampling density in the step (1.1) is 4 points/km ² to 500 points/km ² ; in the step (1.2), 200g to 500g of the soil at the top of the B layer is collected, and the sieved soil is taken 10g～50g, bake at 105℃～110℃ for 2 hours, cool to room temperature and set aside.

Described step (2.1) specifically comprises the following steps:

1. Get samples of a certain quality from the soil at the top of the B layer at each sampling point in the above-mentioned steps (1) and place them in containers respectively;

② Add the mixed solution of ammonium citrate and ammonium carbonate to each container, stir the mixed solution, place it for a certain period of time, and then filter it, and the filtrate is taken over by a colorimetric tube;

③ Rinse the filtrate in the colorimetric tube in the above step ② to a certain scale with deionized water, and shake well;

④ Extract a certain volume of the filtrate prepared in the above step ③ into the first colorimetric tube, then add nitric acid solution to the colorimetric tube, rinse with deionized water to a certain scale and shake well.

The quality of the sample taken in the first step in the step (2.1) is 2.5000g, and the container is a 50ml beaker;

The second step in the described step (2.1) is to add 20ml concentration respectively in each 50ml beaker and be the mixed solution of ammonium citrate and 0.1mol/L ammonium carbonate of 0.1mol/L, and the filtrate is mixed with 25ml plug ratio. Color tube undertaking;

The 3rd step in the described step (2.1) is to flush the filtrate in the above-mentioned step 2. colorimetric tube to 25ml scale with deionized water, shake up;

The 4th step in the described step (2.1) extracts respectively the filtrate prepared in 1.00ml above-mentioned steps 3. in the 10ml colorimetric tube, then adds 1ml nitric acid (1+2) solution in this colorimetric tube, uses Rinse with ionized water to the 10ml mark and shake well.

In the step (2.2), the ICP-MS method is used to determine the uranium content.

Described step (3.1) specifically comprises the following steps:

① Take samples of a certain quality from the soil at the top of layer B at each sampling point in the above step (1) and place them in containers respectively, add hydrochloric acid to the container, and put red copper sheets treated with nitric acid into the hydrochloric acid solution. ;

② Shake the hydrochloric acid solution containing the round red copper sheet treated with nitric acid in the above step ① at a certain temperature, take out the red copper sheet, rinse it with deionized water, and dry it.

The quality of the sample taken in the 1. step in the described step (3.1) is 2.0000g, and the container is a 100ml beaker, and the hydrochloric acid added is the hydrochloric acid of 20 milliliters of 2mol/L, and the copper sheet is a round copper sheet;

The second step in the step (3.1) is to shake the hydrochloric acid solution at 60°C to 80°C for 3 hours to 5 hours. At this time, ²¹⁰ Po is enriched on the round copper sheet, and after taking out the round red copper sheet, deionized water Rinse, then blot dry with filter paper.

In the described step (3.2), measure the α-ray intensity on the front side of the round red copper sheet with an α-ray intensity measuring instrument.

The beneficial technical effects of the present invention are: the method of the present invention can effectively discover and identify the overburden layer with a thickness of ^{tens of} meters to several tens of meters to several The 100-meter hidden hydrothermal uranium deposit is abnormal. The method is simple, fast, low in cost, high in efficiency, strong in effectiveness and large in detection depth, and is a direct prospecting method. Carry out this method of measurement before the drilling work, so that the drilling work that costs more money can be concentrated in the target area, which will greatly reduce the drilling workload, improve the hit rate of ore prospecting, speed up the prospecting speed, shorten the exploration cycle, reduce Provide favorable backup areas for uranium resource exploration at low cost and relatively quickly.

Description of drawings

Figure 1 is a contour map of the uranium content in the exploration of hydrothermal uranium deposits in a certain area of my country;

Fig. 2 is the ²¹⁰ po contour map of hydrothermal uranium deposit exploration in a certain area of China.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments.

A method for trace exploration of hydrothermal uranium ore by combination of geochemical elements, specifically comprising the following steps:

(1) Soil sample collection and processing

(1.1) Select sampling points in the survey area, and the sampling density is 4 points/km ² to 500 points/km ² ;

The sampling density can be selected as 4 points/km ² , 10 points/km ² , 20 points/km ² , 30 points/km ² , 40 points/km ² , 50 points/km ² and 100 points /km ² , 200 points/km ² , 300 points/km ² , 400 points/km ² or 500 points/km ² .

(1.2) Collect 200g-500g of soil at the top of layer B at each sampling point, and pass the collected soil at the top of layer B through a -80 mesh sieve. Take 10g-50g of sieved soil at each sampling point, bake at 105°C-110°C for 2 hours, cool to room temperature and set aside.

200g, 300g, 400g or 500g of soil at the top of layer B can be collected and baked at 105°C, 107°C or 110°C for 2 hours.

(2) Measure the uranium content in the soil of the exploration area

(2.1) Extraction of uranium content

1. Take 2.5000g sample from the soil at the top of layer B prepared at each sampling point in the above step (1), and place each sample in a 50ml beaker;

②Add 20ml of mixed solution of ammonium citrate and 0.1mol/L ammonium carbonate with a concentration of 0.1mol/L to each 50ml beaker, stir the mixed solution and let it sit for 24 hours before filtering it. It can be filtered with ordinary funnel filter paper. Use a 25ml stoppered colorimetric tube to undertake;

Ammonium citrate and ammonium carbonate were of analytical grade.

③ Rinse the filtrate in the colorimetric tube in the above step ② to the 25ml mark with deionized water, and shake well;

④Extract 1.00ml of the filtrate prepared in the above step ③ into a 10ml colorimetric tube, then add 1ml of nitric acid (1+2) solution to the colorimetric tube, flush to the 10ml mark with deionized water, and shake well.

(2.2) Determination of uranium content

Use the ICP-MS method (plasma mass spectrometry) to measure the uranium content of the solution in the 10ml colorimetric tube after flushing with deionized water in the ④ step of the above-mentioned steps (2.1), that is, obtain the uranium content of the sampling point , the uranium content is the content of active uranium in the soil, and the unit of uranium content is ng/g.

(3) Measure ²¹⁰ Po

(3.1) Extraction of ²¹⁰ Po

① Take 2.0000g sample from the soil at the top of the B layer at each sampling point in the above step (1), put it in a 100ml beaker, add 20ml of 2mol/L hydrochloric acid to the 100ml beaker respectively, and add 2mol/L hydrochloric acid to the hydrochloric acid solution Put in the round copper sheet treated with nitric acid, the diameter of the round copper sheet is 1.9 cm, and the thickness is 0.2-0.5 mm;

② Shake the hydrochloric acid solution containing the round copper sheet treated with nitric acid in the above step ① at 60°C-80°C for 3 hours to 5 hours. At this time, ²¹⁰ Po is enriched on the round copper sheet. Rinse with deionized water and blot dry with filter paper.

The shaking temperature may be 60°C, 70°C or 80°C. The shaking time can be 3 hours, 4 hours or 5 hours.

(3.2) Determination of ²¹⁰ Po

Use an α-ray intensity measuring instrument to measure the α-ray intensity (unit: Bq.Kg ^-1 ) of the front side (that is, the side that is not painted) of the round copper sheet to obtain the content of ²¹⁰ Po in the soil.

When measuring ²¹⁰ Po, the sample reading time for each sampling point is 10 minutes.

(4) Make plane contour maps of uranium content and ²¹⁰ Po elements

According to the measurement results of the above steps (2) and (3), the uranium component contour map and the ²¹⁰ Po element plane contour map were respectively produced by Sufer software, and the mineralization prospect area was preliminarily circled.

It is also possible to use any software in the prior art to make a uranium component contour map and ^{a 210} Po element plane contour map.

(5) Determine whether there are hydrothermal uranium deposits in the exploration area through the identification of ore-induced anomalies

(5.1) According to the ratio of uranium content/total uranium content, it is judged whether it is abnormal mineral-induced uranium content

If the ratio of uranium content/total uranium is greater than or equal to 0.1, it is an anomaly of uranium content caused by ore; if the ratio of uranium content/total uranium is less than 0.1, it is an anomaly of uranium content caused by non-mineralization.

The total amount of uranium in the soil in the exploration area was determined by ICP-MS (plasma mass spectrometry).

(5.2) If it is judged by the above steps (5.1) that the exploration area is abnormal in ore-induced uranium content, it is further inferred whether there is a hydrothermal uranium deposit in the exploration area based on the following conditions:

① Through the uranium content contour map, check whether there is an abnormal distribution of gradually enriched uranium content and a strong uranium content abnormal concentration center. The abnormal uranium content concentration center is from the outer zone to the middle zone and then to the inner zone Areas where the uranium content gradually increases;

② Through the ²¹⁰ Po contour map, check whether there is a combination of uranium content and ²¹⁰ Po anomaly, that is, whether the corresponding anomalous areas basically overlap;

③Whether the uranium component anomalous area corresponds to the favorable ore-forming fault structural alteration zone is a composite section, that is, the anomalous area is superimposed on the geological map of the area to see whether the ore-forming fault structural alteration zone passes through the anomalous area.

If at least two of the inference conclusions of steps ①-③ in the above step (5.2) are affirmative, it is determined that there are hydrothermal uranium deposits in the exploration area; otherwise, there is no hydrothermal uranium deposit in the exploration area.

Below is the concrete process that adopts method of the present invention to carry out prospecting in certain area of my country:

Sampling and extraction of uranium content and ²¹⁰ Po from this area, after the measurement by ICP-MS method and α-ray measuring instrument, the contour map of uranium content in this area is shown in Figure 1, and the contour map of ²¹⁰ Po is shown in Figure 2 .

Using the above method to measure the ratio of uranium content/total uranium in most of the measuring points in this area is greater than or equal to 0.1, which is an anomaly of mineral-induced active uranium.

The lower limit of abnormal uranium content in this area is 1150ng/g calculated by iterative elimination statistical method. With 1150ng/g as the lower limit of ^{the outer zone anomaly, circle the regional anomalous area of uranium content with an area of nearly 100Km 2 ;} A local anomalous area of uranium content with an area of nearly ^50Km2 is found; similarly, in this local anomalous area with an area of nearly ^50Km2 , 2660ng/g is used as the lower limit value of the inner band anomaly to circle the central area of abnormal concentration of uranium content. As can be seen from Figure 1, it can be seen that there is an area where the uranium content gradually increases from the outer zone to the middle zone, and then to the inner zone; that is, there is an abnormal concentration center of uranium content.

Combined with Figure 2, it can be seen that the uranium content and ²¹⁰ Po anomalies in this region have a high coincidence degree (according to ²¹⁰ Po 37Bq/Kg as the lower limit of the outer anomaly, 57Bq/Kg as the lower limit of the middle anomaly, and 75Bq /Kg is used as the lower limit of the inner belt abnormality). Hydrological, geological and other investigations have found that the anomalous area of soil uranium content in this area is correspondingly compounded with the fault structural alteration zone that is favorable for mineralization. In summary, it is inferred that there are hydrothermal uranium deposits underground in this area, which has been confirmed by drilling engineering.

The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Within the scope of knowledge of those of ordinary skill in the art, various modifications can be made without departing from the gist of the present invention. kind of change. The content that is not described in detail in the description of the present invention can adopt the prior art.

Claims (9)

1. A method for trace exploration of hydrothermal uranium ore by combination of geochemical elements, characterized in that: it comprises the following steps: (1) Soil sample collection and processing Select sampling points in the survey area with a certain sampling density, and collect a certain quality of soil at the top of layer B at each sampling point; (2) Measure the uranium content in the soil of the exploration area (2.1) Extraction of uranium content Get a certain amount of soil at the top of the B layer in the above step (1) and place it in a container, and add a mixed solution of ammonium citrate and ammonium carbonate to the container, stir and filter after placing, the filtrate is accepted by the first colorimetric tube, and the Rinse the filtrate in the first colorimetric tube with deionized water and shake well; extract a certain volume of filtrate rinsed with deionized water, place it in the second colorimetric tube, and pour it into the second colorimetric tube Add nitric acid solution, rinse with deionized water and shake well; (2.2) Determination of uranium content Determination of the uranium content of the solution flushed with deionized water in the second colorimetric tube of the above step (2.1), promptly obtains the uranium content of the sampling point; (3) Measure ²¹⁰ Po (3.1) Extraction of ²¹⁰ Po Get a certain amount of soil at the top of the B layer in the above-mentioned steps (1) and place it in a container, and add hydrochloric acid to the container, then put into the red copper sheet that has been treated with nitric acid; Oscillate, at this time ²¹⁰ Po is enriched on the copper sheet, take out the round copper sheet; (3.2) Determination of ²¹⁰ Po Measure the α-ray intensity of the copper sheet to obtain the content of ²¹⁰ Po in the soil; (4) Make plane contour maps of uranium content and ²¹⁰ Po elements According to the measurement results of the above steps (2) and (3), a uranium component contour map and a ²¹⁰ Po element plane contour map are produced, and the mineralization prospect area is preliminarily circled; (5) Determine whether there are hydrothermal uranium deposits in the exploration area through the identification of ore-induced anomalies (5.1) According to the ratio of uranium content/total uranium content, it is judged whether it is abnormal mineral-induced uranium content If the ratio of uranium content/total uranium is greater than or equal to 0.1, it is an abnormality of uranium content caused by ore; if the ratio of uranium content/total uranium is less than 0.1, it is an anomaly of non-mineral uranium content; (5.2) If it is anomalous uranium content caused by ore, it is further inferred whether there is a hydrothermal uranium deposit in the exploration area based on the following conditions: ① Through the contour map of uranium content, whether there is an anomalous distribution pattern of overlapping and gradually enriched uranium content and a strong uranium content anomalous concentration center, that is, the uranium content gradually increases from the outer zone to the middle zone, and then to the inner zone. high area; ② Through the ²¹⁰ Po contour map, check whether there is a combination of uranium content and ²¹⁰ Po anomaly, that is, whether the corresponding anomalous areas basically overlap; ③Whether the uranium component anomalous area corresponds to the favorable ore-forming fault structural alteration zone is a composite section, that is, the anomalous area is superimposed on the geological map of the area to see whether the ore-forming fault structural alteration zone passes through the anomalous area. If at least two of the inference conclusions of steps ①-③ in the above step (5.2) are affirmative, it can be determined that there are hydrothermal uranium deposits in the exploration area; otherwise, there is no hydrothermal uranium deposit in the exploration area. 2. The method for tracing and prospecting hydrothermal uranium deposits according to claim 1, wherein said step (1) specifically comprises the following steps: (1.1) Select sampling points in the survey area with a certain sampling density; (1.2) Collect a certain quality of soil at the top of layer B at each sampling point, sieve the collected soil at the top of layer B, and get a certain quality of soil after sieving at each sampling point, first dry and then cool to room temperature Backup. 3. A method for tracing and prospecting hydrothermal uranium deposits according to claim 2, characterized in that: the sampling density in the step (1.1) is 4 points/km ² -500 points/km ² ; in the step (1.2), collect 200g-500g of soil at the top of layer B, take 10g-50g of sieved soil, bake at 105°C-110°C for 2h, cool to room temperature and set aside. 4. The method for tracing and prospecting hydrothermal uranium deposits according to a combination of geochemical elements according to claim 1, 2 or 3, characterized in that: said step (2.1) specifically comprises the following steps: 1. Get samples of a certain quality from the soil at the top of the B layer at each sampling point in the above-mentioned steps (1) and place them in containers respectively; ② Add the mixed solution of ammonium citrate and ammonium carbonate to each container, stir the mixed solution, place it for a certain period of time, and then filter it, and the filtrate is taken over by a colorimetric tube; ③ Rinse the filtrate in the colorimetric tube in the above step ② to a certain mark with deionized water and shake well; ④ Extract a certain volume of the filtrate prepared in the above step ③ into the first colorimetric tube, then add nitric acid solution to the colorimetric tube, flush to a certain scale with deionized water and shake well. 5. the method for a kind of geochemical element combination tracer exploration hydrothermal uranium ore according to claim 4, is characterized in that: the quality of sample taken in the 1. step in the described step (2.1) 2.5000g, the container is a 50ml beaker; The second step in the described step (2.1) is to add 20ml concentration respectively in each 50ml beaker and be the mixed solution of ammonium citrate and 0.1mol/L ammonium carbonate of 0.1mol/L, and the filtrate is mixed with 25ml plug ratio. Color tube undertaking; The 3rd step in the described step (2.1) is to flush the filtrate in the above-mentioned step 2. colorimetric tube to 25ml scale with deionized water, shake up; The 4th step in the described step (2.1) extracts respectively the filtrate prepared in 1.00ml above-mentioned steps 3. in the 10ml colorimetric tube, then adds 1ml nitric acid (1+2) solution in this colorimetric tube, uses Rinse with ionized water to the 10ml mark and shake well. 6 . The method for tracing and prospecting hydrothermal uranium ore by combination of geochemical elements according to claim 5 , characterized in that: in the step (2.2), the uranium content is determined by ICP-MS. 7. The method for tracing and prospecting hydrothermal uranium deposits according to claim 6, wherein said step (3.1) specifically comprises the following steps: ① Take samples of a certain quality from the soil at the top of layer B at each sampling point in the above step (1) and place them in containers respectively, add hydrochloric acid to the container, and put red copper sheets treated with nitric acid into the hydrochloric acid solution. ; ② Shake the hydrochloric acid solution containing the round red copper sheet treated with nitric acid in the above step ① at a certain temperature, take out the red copper sheet, rinse it with deionized water, and dry it. 8. the method for a kind of geochemical element combination tracer exploration hydrothermal uranium ore according to claim 7, is characterized in that: the quality of the sample taken in the ① step in the described step (3.1) 2.0000g, the container is a 100ml beaker, the hydrochloric acid added is 20ml of 2mol/L hydrochloric acid, and the copper sheet is a round copper sheet; The second step in the step (3.1) is to shake the hydrochloric acid solution at 60°C to 80°C for 3 hours to 5 hours. At this time, ²¹⁰ Po is enriched on the round copper sheet, and after taking out the round red copper sheet, deionized water Rinse, then blot dry with filter paper. 9. the method for a kind of geochemical element combination tracer exploration hydrothermal uranium ore according to claim 8, is characterized in that: in described step (3.2), measure the radiance of round red copper plate front with alpha ray intensity measuring instrument Alpha ray intensity.

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