CN111896574A - An immersion type lanthanum extraction on-site detection system and detection method - Google Patents

Abstract

The invention discloses an immersed lanthanum extraction on-site detection system and a detection method. A detection pipe is arranged in a cavity, a protrusion is arranged at the bottom of the detection pipe, a high-purity germanium detector is arranged in the protrusion, and the outer wall of the high-purity germanium detector is enclosed Covered with thermal insulation cotton, and a shielding ring is arranged at the bottom; a flow sensor and a density sensor are arranged in the detection pipeline, and a gamma energy spectrometer and a PLC controller are arranged outside the cavity. The flow sensor, density sensor and gamma energy spectrometer The output terminal is connected to the PLC controller. During detection, the PLC controller extracts N _A , N _b from the energy spectrum; and calculates the detection sensitivity S of lanthanum, the mass DM of lanthanum in the extract, and the minimum detectable mass MDM in combination with real-time flow rate, density, etc. The method realizes the on-line control of the extraction quality of the rare earth element lanthanum. Compared with the traditional quality control method of the rare earth element lanthanum beneficiation and smelting process, there is no need to design a sample injection system separately, and it has the characteristics of high distribution degree, good timeliness, low detection limit and high sensitivity. .

Description

An immersion type lanthanum extraction on-site detection system and detection method

technical field

The invention relates to an on-line detection system and method in a lanthanum extraction process, in particular to an immersion type lanthanum extraction on-site detection system and detection method.

Background technique

Weathered crust leaching type rare earth ore is one of the important types of rare earth deposits in my country. At present, cascade extraction method is used for this type of rare earth ore dressing and smelting in China to separate single rare earth elements. Lanthanum is an important rare earth element in weathered crust leaching rare earth ore, and its mass distribution ratio can reach 29.09%. Therefore, the detection of mass ratio in the separation process is of great significance.

At this stage, the detection of element distribution characteristics in the process of rare earth ore beneficiation and smelting generally includes the detection of rare earth ore solids, such as chemical analysis, ICP-MS, ICP-AES, and the detection of rare earth extracts, such as EDXFF, WDXRF and other methods. . Most of the above methods need to rely on large-scale experimental equipment. The sampling, sample preparation, testing and other processes often take several hours or even a day of practice, and the timeliness of testing is relatively lagging.

For example, the chemical analysis method in the prior art requires the experimenter to sample in the extraction tank and send it to the relevant laboratory. The sample needs to undergo pretreatment processes such as precipitation, impurity removal, dilution, extraction, and configuration. The detection period is long, and there are many types of experimental equipment required. The detection process of ICP-AES, ICP-MS and other detection methods is similar to that of chemical analysis, and all require sample pretreatment. In addition, the equipment cost of this type of detection method is relatively high, and the requirements for the detection environment are relatively harsh.

Fluorescence detection methods such as WDXRF and EDXRF are the on-site detection methods that can be used in rare earth beneficiation and metallurgy in recent years. Compared with traditional detection methods, this method requires less sample pretreatment. However, a high-power x-ray tube is still required as an excitation source to excite the characteristic x-rays of various elements in the extract to achieve the purpose of quantitative detection. Let us take the reference document CN105136831A as an example. Although this patented method uses extraction liquid to measure, it uses energy dispersive X-rays to analyze the mass distribution ratio of lanthanum in rare earth elements. In this method, X-rays must be used to irradiate the sample to excite the L-ray fluorescence in rare earth elements, so an excitation source must be used, and this method requires an active sample feeding device such as a peristaltic pump, and an extraction liquid backflow sealed connection pipeline. The system is complicated and the cost is high.

In addition, under the technical background of continuously improving extraction efficiency, the existing detection methods are difficult to match with extraction equipment with a high level of automation, resulting in low production efficiency and unstable product quality. Therefore, an efficient, stable, simple-structured, and distributed continuous detection system is urgently needed to achieve product quality control at key process nodes.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide an immersion lanthanum extraction on-site detection system and detection method which can solve the above problems, can effectively improve the online detection sensitivity of the lanthanum extraction process, and reduce the online detection limit.

In order to achieve the above purpose, the technical solution adopted in the present invention is as follows: an immersed lanthanum extraction on-site detection system includes a cavity, and the cavity is provided with a detection pipeline horizontally running through both ends thereof, and the detection pipeline is used for flowing through the lanthanum extract;

The bottom of the detection pipe is provided with a protrusion toward the center, the protrusion is cylindrical, and a high-purity germanium detector is arranged in the protrusion. The high-purity germanium detector is facing the inside of the detection pipe, and the top and the protrusion The top of the shielding ring is fitted, the outer wall is covered with thermal insulation cotton, and the bottom is provided with a shielding ring, and the bottom of the shielding ring is flush with the bottom of the protrusion;

The detection pipeline is provided with a flow sensor, a density sensor, and a gamma energy spectrometer and a PLC controller are arranged outside the cavity, and the output ends of the flow sensor, the density sensor and the gamma energy spectrometer are connected to the PLC controller;

The flow sensor and the density sensor are respectively used to collect flow velocity information v and real-time density information ρ of the extraction liquid;

The output end of the high-purity germanium detector is connected to a gamma energy spectrometer, which is used to detect the gamma rays in the extract and obtain the energy spectrum through the analysis of the gamma energy spectrometer;

The PLC controller is used for setting the measurement time t, extracting the characteristic peak count N _A and the characteristic all-energy peak interval background count N _b of the gamma ray with energy of 1.435MeV in Lanthanum-138 from the energy spectrum, combined with the flow rate information v, real-time density information ρ, and obtain the detection sensitivity S of lanthanum, the quality DM of lanthanum in the extract according to the following formula:

S=η·A _La ·γ

In the formula: η is the detection efficiency of the gamma spectrometer, γ is the branch ratio of 1.435MeV rays, the value is 65.5%, A _La is the specific activity of natural lanthanum, the value is 826.63Bq/kg, A _S is the test Lanthanum-138 activity in the extract.

Preferably, the detection pipeline is made of stainless steel or PVC material. If the detection pipeline is made of stainless steel, a corrosion-resistant layer is provided in the detection pipeline, and the corrosion-resistant layer is made of polytetrafluoroethylene and its derivatives.

Preferably, the cross section of the detection pipe is circular, the inner diameter is 30cm, the outer diameter is 32cm, the size of the protrusion is 15cm*12cm, the wall thickness is 1mm, and the thickness of the insulation cotton is 2cm.

Preferably, the relative detection efficiency of the high-purity germanium detector is greater than or equal to 120%, and the electrical cooling method is adopted, including cold fingers and signal lines, which are led out from the holes in the middle of the lead shielding ring.

A detection method for an immersed lanthanum extraction on-site detection system, comprising the following steps:

(1) Establish an immersion lanthanum extraction on-site detection system, and connect the detection pipeline in series on the pipeline through which the extraction liquid to be tested flows;

(2) Start the system, the flow sensor and density sensor collect the flow rate information v and real-time density information ρ of the extract, the high-purity germanium detector detects the gamma rays in the extract, and sends it to the gamma spectrometer for analysis. Measure energy spectrum and output;

(3) The PLC controller extracts the 1.435MeV characteristic peak count N _A of lanthanum-138 from the superposition energy spectrum, the background count N _b of the characteristic all-energy peak interval; and calculates the detection sensitivity S of lanthanum and the extraction liquid according to the following formula Lanthanum quality DM;

S=η·A _La ·γ

In the formula: η is the detection efficiency of the gamma spectrometer, γ is the branch ratio of 1.435MeV rays, the value is 65.5%, A _La is the specific activity of natural lanthanum, the value is 826.63Bq/kg, A _S is the test Lanthanum-138 activity in the extract.

As preferably: also include step (4), calculate the minimum detectable mass MDM of lanthanum according to the following formula;

The present invention is used to measure the gamma ray characteristic peak of the radioisotope lanthanum-138 in the extract with an energy of 1.435 MeV, and to calculate the mass distribution ratio of lanthanum in rare earth elements by measuring the gamma ray characteristic peak. And by the method of the present invention, the detection sensitivity S of lanthanum is higher, and the minimum detectable mass MDM is lower.

In the present invention, the detection pipe is made of stainless steel or PVC material. If it is stainless steel, a corrosion-resistant layer is arranged in the detection pipe, and the corrosion-resistant layer is made of polytetrafluoroethylene and its derivatives. This is because the extraction liquid is corrosive to a certain extent. If stainless steel is used, a corrosion-resistant layer needs to be used.

The detector is a high-purity germanium detector, which realizes the measurement of the 1.435MeV characteristic gamma ray of the lanthanum-138 nuclide in the extraction liquid flowing in the pipeline. There is a protrusion at the bottom of the detection pipe, and the detector is located in the protrusion, which is equivalent to "immersing" in the extraction liquid, which increases the detection solid angle of the detector, and can increase the effective count of the characteristic peak of gamma rays with an energy of 1.435MeV N _A. At the same time, the detector is "immersed" in the extraction liquid, which can also achieve "self-shielding" of the radioactive background in the surrounding environment, that is, reducing the background count and reducing N _b .

We cover the outer wall of the high-purity germanium detector with thermal insulation cotton. The purpose is: the performance of the detector is affected by the working temperature. In addition to the built-in refrigeration components, in this design, the thermal insulation cotton can keep the temperature in the bulge relatively constant and reduce the temperature. Influence of temperature variation of extraction liquid in pipeline on detector performance.

可知，提高N_A，降低N_b，能有效提高了特征峰的峰背比ξ。There is a shielding ring at the bottom, which is used to shield the gamma ray interference from the decay of natural radionuclides of U series, Th series and ⁴⁰ K in the natural environment, as well as the gamma ray interference generated by other natural and artificial radionuclides that may exist. Further, the purpose of further reducing the background count N _b is achieved. According to the formula

It can be seen that increasing N _A and decreasing N _b can effectively increase the peak-to-background ratio ξ of the characteristic peaks.

来计算镧的检测灵敏度S，由于提高了N_A，可以提高伽马能谱仪的检测灵敏η，又因为A_La为天然镧的比活度，为常量，γ为1.435MeV射线的分支比，也为常量，值为65.5％％。所以从公式可知，能提高镧的检测灵敏度S。In the present invention, we use the formula S=η·A _La ·γ,

To calculate the detection sensitivity S of lanthanum, due to the increase of N _A , the detection sensitivity η of the gamma energy spectrometer can be improved, and because A _La is the specific activity of natural lanthanum, which is a constant, and γ is the branching ratio of 1.435MeV rays, Also a constant with a value of 65.5%%. Therefore, it can be seen from the formula that the detection sensitivity S of lanthanum can be improved.

来计算镧的最小可探测质量MDM，由于降低了N_b，本发明能有效降低镧的最小可探测质量MDM。The present invention utilizes the formula

To calculate the minimum detectable mass MDM of lanthanum, due to reducing N _b , the present invention can effectively reduce the minimum detectable mass MDM of lanthanum.

The MDM of the present invention, that is, the minimum detection quality that the detection system can achieve under certain confidence conditions, is calculated by the following methods:

是在单边置信概率95％条件下，伽马能谱仪的计数率的检出限，所以，上述公式可改写为如下方式所：In the formula, LD is the detection limit of the effective counting of lanthanum-138 characteristic peak area by the gamma spectrometer, m is the quality of the extraction liquid in the pipeline, the formula is m= _ρ v t, the permeable density, flow rate, The measurement time t is calculated. and

is the detection limit of the count rate of the gamma spectrometer under the condition of a unilateral confidence probability of 95%. Therefore, the above formula can be rewritten as follows:

It can be seen that when the state of the extract is stable, the MDM is proportional to the background count N _b in the characteristic tompotent peak interval, and inversely proportional to the measurement time t. Through effective structural design, the device of the present invention can reduce N _b , improve detection efficiency η, and further effectively reduce MDM.

由伽马能谱仪测量；而γ、A_La、η为常量，ρ、v可由流量、密度传感器得知；t为测量时间，由检测系统设定。可见，当萃取液的状态稳定时，MDM与本底计数成正比，与测量时间成反比。In this formula, the background count in the characteristic peak area

It is measured by a gamma energy spectrometer; while γ, A _La , and η are constants, and ρ and v can be known by flow and density sensors; t is the measurement time, which is set by the detection system. It can be seen that when the state of the extract is stable, the MDM is proportional to the background count and inversely proportional to the measurement time.

The integrated measuring pipeline is connected with the extraction centrifuge pipeline, and the measuring instrument is connected in series in the technological process of the multi-stage extraction centrifuge, without additional equipment such as "peristaltic pump". Compared with the current online analysis methods based on spectrophotometric online analysis method and x-fluorescence online analysis method, there is no need to separately design the extraction liquid sample return pipeline.

Compared with the prior art, the advantages of the present invention are:

(1) The present invention proposes a new detection device and method. The device is used to directly detect the extraction solution to extract the characteristic peak count N of gamma rays with an energy of 1.435MeV in lanthanum-138 from the superimposed energy spectrum of the extraction solution. _A. The background count N _b in the characteristic all-energy peak interval, and combined with the flow rate information v and the real-time density information ρ, the detection sensitivity S of lanthanum, the mass DM of lanthanum in the extract, and the minimum detectable mass MDM can be obtained. The invention overcomes the defects in the prior art that detection and analysis must be performed through solid sampling, or an active excitation source must be relied on for extracting liquid to excite and measure the activity of natural radionuclides in the extracting liquid. A method for DM measurement was proposed by extracting the characteristic peak count N _A of gamma rays and the background count N _b in the characteristic all-energy peak interval from the energy spectrum of the extract. The method extracts the characteristic peak count N _A and the characteristic all-energy peak interval background count N _b of gamma rays with an energy of 1.435 MeV in Lanthanum-138 from the superimposed energy spectrum of the extract, and combines the flow velocity information v and real-time density information ρ , the detection sensitivity S of lanthanum, the mass DM of lanthanum in the extract, and the minimum detectable mass MDM can be obtained.

(2) The present invention has simple structure and convenient installation, which can not only detect single-stage extraction quality, but also realize multi-stage serial quality process detection. When installing, it is directly installed in series between the extraction cells or on the pipeline where the extraction liquid flows, without additional equipment such as peristaltic pumps, which can effectively simplify the extraction liquid return pipeline, and the system design is simpler and the cost is lower.

(3) Compared with the existing spectrophotometric on-line analysis method, x-fluorescence on-line analysis method, etc., the present invention does not need an active excitation source, directly measures the activity of natural radionuclides in the extract, and belongs to a passive detection method, and the detection result is affected by The influence of the instrument itself is smaller, which can effectively avoid the influence of the equipment itself on the detection results, and based on the structure of the present invention, N _A can be effectively increased and N _b can be reduced, so that the detection sensitivity S of lanthanum is higher, and the minimum detectable Quality MDM is lower.

Description of drawings

Fig. 1 is the structural representation of the present invention;

Fig. 2 is the A-A sectional view of the detection pipeline in Fig. 1;

FIG. 3 is a B-B cross-sectional view of the detection pipeline in FIG. 1

Fig. 4 is the sampling flow schematic diagram of the traditional multistage extraction tank online detection system;

Fig. 5 is the sampling flow schematic diagram of the present invention;

Fig. 6 is the full spectrum in the measuring process of the present invention;

FIG. 7 is a processed real-time measurement background energy spectrum after the arrow region in FIG. 6 is expanded.

In the figure: 1. cavity; 2. detection pipeline; 3. high-purity germanium detector; 4. thermal insulation cotton; 5. flow sensor; 6. density sensor; 7. shielding ring; 8. status indicator light; 9. Power supply and data interface; 10. Protrusion.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings.

Example 1: Referring to Figures 1 to 3, an immersion type lanthanum extraction on-site detection system includes a cavity 1, and a detection pipeline 2 horizontally running through both ends of the cavity 1 is arranged in the cavity 1. The detection pipeline 2 uses to flow through the lanthanum extract;

The bottom of the detection pipe 2 is provided with a protrusion 10 facing its center, the protrusion 10 is cylindrical, and a high-purity germanium detector 3 is arranged in the protrusion 10, and the high-purity germanium detector 3 is facing the detection pipe 2. Inside, the top is attached to the top of the protrusion 10, the outer wall is covered with thermal insulation cotton 4, and the bottom is provided with a shielding ring 7, and the bottom of the shielding ring 7 is flush with the bottom of the protrusion 10;

The detection pipeline 2 is provided with a flow sensor 5, a density sensor 6, and a gamma energy spectrometer and a PLC controller outside the cavity 1. The output ends of the flow sensor 5, the density sensor 6 and the gamma energy spectrometer are provided. Connect PLC controller;

The flow sensor 5 and the density sensor 6 are respectively used to collect flow velocity information v and real-time density information ρ of the extraction liquid;

The output end of the high-purity germanium detector 3 is connected to a gamma energy spectrometer, which is used to detect the gamma rays in the extraction solution and analyze the energy spectrum by the gamma energy spectrometer;

The PLC controller is used for setting the measurement time t, extracting the characteristic peak count N _A and the characteristic all-energy peak interval background count N _b of the gamma ray with energy of 1.435MeV in Lanthanum-138 from the energy spectrum, combined with the flow rate information v, real-time density information ρ, and obtain the detection sensitivity S of lanthanum, the quality DM of lanthanum in the extract according to the following formula:

S=η·A _La ·γ

In the formula: η is the detection efficiency of the gamma spectrometer, γ is the branch ratio of 1.435MeV rays, the value is 65.5%, A _La is the specific activity of natural lanthanum, the value is 826.63Bq/kg, A _S is the test Lanthanum-138 activity in the extract.

The detection pipe 2 is made of stainless steel material or PVC material. If the detection pipe 2 is made of stainless steel, a corrosion-resistant layer is provided in the detection pipe 2, and the material of the corrosion-resistant layer is polytetrafluoroethylene and its derivatives.

The cross section of the detection pipe 2 is annular, the inner diameter is 30cm, the outer diameter is 32cm, the size of the protrusion 10 is 15cm*12cm, the wall thickness is 1mm, and the thickness of the insulation cotton 4 is 2cm.

The relative detection efficiency of the high-purity germanium detector 3 is greater than or equal to 120%, and electrical cooling is adopted, including cold fingers and signal lines, which are drawn out from the holes in the middle of the lead shielding ring 7 . In this embodiment, the high-purity germanium detector 3 is a Canberra GX12021 type detector. If other types of detectors can be used to achieve the same effect, they all belong to the protection scope of the present invention.

A detection method for an immersed lanthanum extraction on-site detection system, comprising the following steps:

(1) establish an immersion lanthanum extraction on-site detection system, and connect the detection pipeline 2 in series on the pipeline through which the extraction liquid to be tested flows;

(2) Start the system, the flow sensor 5 and the density sensor 6 collect the flow rate information v and real-time density information ρ of the extraction liquid, and the high-purity germanium detector 3 detects the gamma rays in the extraction liquid and sends them to the gamma energy spectrometer The measured energy spectrum is obtained by the analysis in the middle and output;

(3) The PLC controller extracts the 1.435MeV characteristic peak count N _A of lanthanum-138 from the superposition energy spectrum, the background count N _b of the characteristic all-energy peak interval; and calculates the detection sensitivity S of lanthanum and the extraction liquid according to the following formula Lanthanum quality DM;

S=η·A _La ·γ

In the formula: η is the detection efficiency of the gamma spectrometer, γ is the branch ratio of 1.435MeV rays, the value is 65.5%, A _La is the specific activity of natural lanthanum, the value is 826.63Bq/kg, A _S is the test Lanthanum-138 activity in the extract.

(4) Calculate the minimum detectable mass MDM of lanthanum according to the following formula;

During the measurement, in order to ensure the accuracy of the data, we generally start the measurement after detecting that the flow of the extract is stable. We can also set a status indicator 8 and a power supply and data interface 9 on the outer wall of the cavity 1. The status indicator 8 can be used to indicate whether various sensors and other equipment are working normally, or whether the flow rate and density are stable. Can be set as required. The power supply and data interface 9 is used to supply power to the internal power consumption units.

For example: the detection pipeline 2 is connected in series with the extraction centrifuge, and during the extraction process, the extraction liquid passes through the detection pipeline 2; the flow sensor 5 monitors the flow in the detection pipeline 2 in real time; after the extraction liquid flow is stabilized, the status indicator 8 scintillation; the high-purity germanium detector 3 in the cavity 1 begins to automatically detect the extraction liquid flowing in the pipeline, measures the gamma ray energy spectrum, and sends it to the PLC controller, and the built-in data processing system calculates the The mass distribution amount of the rare earth element lanthanum, and the detection results can be stored locally or uploaded to the main control room through the power supply and data interface 9. The above measurement processes are all controlled by computer software.

As can be seen from FIG. 4 , the present invention relates to an immersed lanthanum extraction on-site detection system and method. The integrated detection pipeline 2 is connected in series in the technological process of the multi-stage extraction centrifuge, and additional equipment such as a “peristaltic pump” is not required. Compared with the current online analysis methods based on "spectrophotometric online analysis method and x-fluorescence online analysis method", there is no need to design the extraction liquid reflux pipeline separately. The sampling system of the present invention is simpler in design and lower in cost.

Embodiment 2: Referring to FIG. 1 to FIG. 5 , on the basis of Embodiment 1, we provide Embodiment 2 applying the device and method of the present invention.

(1) First, we need to establish a plurality of distributed lanthanum extraction on-line detection systems based on γ energy spectroscopy as described in Example 1. Next, install according to Figure 4. In Fig. 4, we set S1 as the original solution pool, and E1-En as n extraction pools, that is, n-level extraction pools, and there are also n immersion lanthanum extraction on-site detection systems of the present invention, which are marked as Q1-Qn respectively. As can be seen from the figure, the present invention directly measures the activity of natural radionuclides in the extract without an active excitation source, which belongs to a passive detection method, and the detection results are less affected by the factors of the instrument itself.

In Figure 4, the flow direction of the liquid is: the stock solution with rare earth metal lanthanum is first placed in the stock solution pool S1, and is connected to the multi-stage extraction pool through a pipeline, and the immersion type lanthanum extraction on-site detection system of the present invention is installed in the pipeline. Specifically, the detection pipeline 2 is connected to the pipeline in series. Then Q1-Qn can respectively analyze and detect the extract of rare earth metal lanthanum flowing out from E1-En.

We take Q1-Qn as detection nodes, and we probe at Q2, which is located between extraction pools E2 and E3. We connect it in series on the pipe between E2 and E3. The flow rate v of the extract to be tested at this node is 5.235L/min, the density ρ is 1.2kg/L, and the activity of the internal natural radionuclide is known, as shown in Table 1:

Table 1 The specific activity (Bq/mL) of natural radionuclides U series, Th series, ⁴⁰ K in the pipeline

U system Th series ⁴⁰K 3.75 0.44 0.15

These natural radionuclides constitute the radioactive background of the extract in the pipeline.

(2) Turn on Q2, the flow sensor 5 and the density sensor 6 simultaneously monitor and collect the extraction liquid flow rate information v is 5.235L/min, the real-time density information ρ is 1.2kg/L; high-purity germanium detector 3, gamma energy spectrometer A detection system is formed to continuously measure the gamma energy spectrum of the natural radionuclide ¹³⁸ L in the extract, and the gamma energy spectrum of the natural radionuclide ¹³⁸ L includes the natural radionuclide and ¹³⁸ La; The spectrum is shown in Figure 6 and Figure 7. As can be seen from the figure, the present invention can make the characteristic peak area of Lan-138 free from gamma ray interference of other nuclides, and in addition, the background value N _b of this peak area has been reduced to 0.7-0.85/min.

(3) The PLC controller extracts the characteristic peak count N _A of the gamma ray with energy of _1.435MeV in Lanthanum-138 from the energy spectrum of Fig. 6 to be 20; Formula to calculate the detection sensitivity S of lanthanum, the value is 0.24count per minute/g, the mass of lanthanum in the extract DM=82g, and the minimum detectable mass MDM;

S=η·A _La ·γ

η is the detection efficiency of the gamma energy spectrometer, which is constrained by N _A , A _S , and is a fixed value, which is 0.7%, and the corresponding A _S of different extracts to be tested is different. γ is the branching ratio of 1.435MeV rays, which is also a fixed value, the value is 65.5%, A _La is the specific activity of natural lanthanum, which is also a fixed value, and the value is 826.63Bq/kg, A _S is the extract to be tested The activity of Lanthanum-138.

We can also calculate the minimum detectable mass MDM of lanthanum according to step (4);

Since N _b is 13.8/min, γ is 65.5%, measurement time t is 1 min, extraction liquid flow rate v is 5.235 L/min, real-time density ρ is 1.2 kg/L, A _La is the specific activity of natural lanthanum, and is 826.63Bq/kg, it can be concluded that the minimum detectable mass MDM is 2.6‰.

Example 3, in order to illustrate that the present invention can reduce the minimum detectable mass of lanthanum obtained by the detection system, we used the device and method of the present invention to select 7 extract samples. Minimum detectable mass.

The seven extract samples have different U-series, Th-series, and ⁴⁰ K specific activity conditions, see Table 2 for details:

Table 2 Specific activity (Bq/mL) of natural radionuclides U series, Th series, and ⁴⁰ K in a certain grade of extract

Test serial number U system Th series ⁴⁰K MDM‰ 1 4.30 0.37 0.30 2.96 2 1.47 0.35 0.17 1.90 3 0.09 0.33 0.17 1.16 4 0.15 0.36 0.21 1.28 5 0.14 0.33 0.20 1.25 6 0.20 4.82 0.22 2.79 7 0.13 0.27 0.14 1.09

At present, the detection methods of lanthanum are all laboratory methods, such as ICP-AES, MS, XRF, etc. For the seven samples described in Table 2, ICP-AES, XRF, chemiluminescence analysis, polarography and voltammetry were used respectively. , the catalytic kinetic fluorescence spectrometry is measured and compared with the measurement results of the method of the present invention to obtain its minimum detectable quality, which can be found in Table 3 for details:

Table 3 Minimum detectable mass of lanthanum by existing analytical techniques

From Table 3, it can be seen that the advantages of the present invention are low in detection limit, which is nearly 1 order of magnitude lower than that of chemiluminescence analysis method, polarography and voltammetry, and XRF method. However, the measurement conditions are simpler, and the on-line detection can be realized without complex equipment and sample preparation and pretreatment processes.

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (6)

1. The utility model provides an immersion lanthanum extraction field detection system, includes a cavity, its characterized in that: a detection pipeline horizontally penetrating through two ends of the cavity is arranged in the cavity and is used for allowing lanthanum extraction liquid to flow through;

the bottom of the detection pipeline is provided with a bulge facing the center of the detection pipeline, the bulge is cylindrical, a high-purity germanium detector is arranged in the bulge, the high-purity germanium detector is right opposite to the inside of the detection pipeline, the top of the high-purity germanium detector is attached to the top of the bulge, the outer wall of the detection pipeline is coated with heat insulation cotton, the bottom of the detection pipeline is provided with a shielding ring, and the bottom of the shielding ring is flush with the bottom;

a flow sensor and a density sensor are arranged in the detection pipeline, a gamma spectrometer and a PLC (programmable logic controller) are arranged outside the cavity, and the output ends of the flow sensor, the density sensor and the gamma spectrometer are connected with the PLC;

the flow sensor and the density sensor are respectively used for acquiring flow velocity information v and real-time density information rho of the extraction liquid;

the output end of the high-purity germanium detector is connected with a gamma energy spectrometer and is used for detecting gamma rays in the extraction liquid and obtaining an energy spectrum through analysis of the gamma energy spectrometer;

the PLC is used for setting the measurement time t and extracting the characteristic peak count N of gamma rays with energy of 1.435MeV in lanthanum-138 from the energy spectrum_ACharacteristic full energy peak interval background count N_bAnd combining the flow velocity information v and the real-time density information rho to obtain the detection sensitivity S of lanthanum and the mass DM of lanthanum in the extraction liquid according to the following formula:

S＝η·A_La·γ

in the formula: eta is the detection efficiency of the gamma spectrometer, gamma is the branch ratio of 1.435MeV rays, the value is 65.5 percent, and A_LaThe specific activity of natural lanthanum is 826.63Bq/kg, A_SThe activity of lanthanum-138 in the extract to be tested.

2. The in-situ immersion lanthanum extraction test system of claim 1, wherein: the detection pipeline is made of stainless steel materials or PVC materials, if the detection pipeline is made of the stainless steel materials, a corrosion-resistant layer is arranged in the detection pipeline, and the corrosion-resistant layer is made of polytetrafluoroethylene and derivatives thereof.

3. The in-situ immersion lanthanum extraction test system of claim 1, wherein: the cross section of the detection pipeline is circular, the inner diameter is 30cm, the outer diameter is 32cm, the size of the bulge is 15cm x12 cm, the wall thickness is 1mm, and the thickness of the heat insulation cotton is 2 cm.

4. The in-situ immersion lanthanum extraction test system of claim 1, wherein: the high-purity germanium detector has a relative detection efficiency of more than or equal to 120%, adopts an electric refrigeration mode and comprises a cold finger and a signal wire, wherein the cold finger and the signal wire are led out from a hole in the middle of a lead shielding ring.

5. The method of claim 1, wherein the at least one sensor is a sensor for detecting the immersion lanthanum extraction field test system, and the method comprises the following steps: the method comprises the following steps:

(1) establishing an immersion lanthanum extraction field detection system, and connecting a detection pipeline in series on a pipeline through which the extract liquid to be detected flows;

(2) starting a system, collecting flow velocity information v and real-time density information rho of the extraction liquid by a flow sensor and a density sensor, detecting gamma rays in the extraction liquid by a high-purity germanium detector, sending the gamma rays into a gamma energy spectrometer for analysis to obtain a measurement energy spectrum, and outputting the measurement energy spectrum;

(3) the PLC extracts the 1.435MeV characteristic peak count N of the lanthanum-138 from the superposition energy spectrum_AThe background count N of the characteristic full energy peak interval_b(ii) a Calculating the detection sensitivity S of lanthanum and the mass DM of lanthanum in the extraction liquid according to the following formula;

S＝η·A_La·γ

in the formula: eta is the detection efficiency of the gamma spectrometer, gamma is the branch ratio of 1.435MeV rays, the value is 65.5 percent, and A_LaThe specific activity of natural lanthanum is 826.63Bq/kg, A_SThe activity of lanthanum-138 in the extract to be tested.

6. The method of claim 5, wherein the at least one sensor is a sensor for detecting the immersion lanthanum extraction field test system, and the method comprises the following steps: further comprising the step (4) of calculating the minimum detectable mass MDM of lanthanum according to the following formula;

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