CN113030067B - Field rapid identification method of rare earth grade in weathering crust leaching type rare earth ore - Google Patents

Abstract

The invention provides a field rapid identification method for rare earth grade of weathering crust leaching type rare earth ore, comprising the following steps: (1) Sampling: weighing a weathering crust leaching type rare earth ore sample to be tested, and recording the quality of the weighed sample to be tested is m; (2) leaching solution preparation: leaching the sample to be weighed in step (1) with ammonium sulfate solution to prepare a leaching solution, the volume of the ammonium sulfate solution is denoted as V; (3) turbidity measurement : slowly drop the leaching solution prepared in step (2) into a turbidity bottle containing a dispersant and an oxalic acid solution, mix evenly immediately after the dropping is completed, and use a turbidimeter to measure the system turbidity T; (4) Calculate the grade of rare earth : Calculate the grade of rare earth in rare earth ore according to formula (2). The invention establishes the conversion relationship between the turbidity of the rare earth oxalate suspension and the rare earth concentration, and only needs to measure the turbidity to identify the rare earth grade in field surveys, which is simpler and faster than directly measuring the rare earth concentration.

Description

Field rapid identification method of rare earth grade in weathering crust leaching type rare earth ore

technical field

The invention belongs to the field of chemical analysis, and particularly relates to a field rapid identification method for rare earth grade of weathered crust leaching type rare earth ore.

Background technique

Weathered crust leaching rare earth ore is a unique and precious resource rich in medium and heavy rare earths in South China. It accounts for about 2.6% of the total rare earth resources in my country, but provides more than 95% of the world's heavy rare earths. The demand for rare earths in modern industry continues to increase, and it is of great significance to investigate and find new weathered crust leached rare earth ore resources to ease the current tense supply situation.

At present, inductively coupled plasma spectrometer/mass spectrometer (ICP-OES, ICP-MS) is often used for accurate determination of rare earth content, but this method requires large and expensive measuring instruments and cannot be used for field surveys. Chi Ruan et al. improved the EDTA titration method based on the national standard GB/T14635-2008 for the rapid determination of rare earth content in the field (CN 102297862 A). However, this method has problems such as insensitivity to discoloration, complex reagents required for portability, and complicated operation procedures (ascorbic acid, sulfosalicylic acid, hexamethylenetetramine, xylenol orange and EDTA need to be added in sequence to the leaching solution) standard solution). Guan Hongli proposed to use saturated oxalic acid solution to precipitate the ammonium sulfate leaching solution of borehole samples, and to observe the morphology of the precipitated products with the naked eye to determine the rare earth grade (CN106353316A). This method is easy to operate in the field, but the accuracy of judging the rare earth content by observing the sediment morphology with the naked eye is low. For example, the method points out that when the soaking solution is lighter white, darker white, white precipitate, or snowflake-like, the rare earth grades belong to different intervals. However, in the actual operation process, it is difficult to distinguish the form of the precipitate with the naked eye, and it is impossible to accurately judge the rare earth content. At the same time, the particle size of rare earth oxalate during precipitation is affected by the feeding method, stirring intensity, temperature, concentration, acidity and other factors, and the precipitate morphology is not completely caused by the rare earth concentration. In addition, the particles will aggregate over time during oxalate precipitation, and it is easy to misjudge when observing samples at different times.

SUMMARY OF THE INVENTION

In order to overcome the problems existing in the prior art, the purpose of the present invention is to provide a field rapid identification method for the rare earth grade of the weathering crust leaching type rare earth ore, which can quickly and accurately measure the rare earth of the weathering crust leaching type rare earth ore in the field high quality, convenient and efficient.

In order to achieve the above object, the present invention adopts the following technical solutions:

A method for rapid field identification of rare earth grade of weathered crust leaching type rare earth ore, comprising the following steps:

(1) Sampling: Weigh the weathered crust leaching type rare earth ore sample to be tested, and the weight of the sample to be tested is recorded as m;

(2) leaching solution preparation: leaching the sample to be weighed in step (1) with ammonium sulfate solution to prepare a leaching solution, and the volume of the ammonium sulfate solution is denoted as V;

(3) Turbidity measurement: slowly drop the leaching solution prepared in step (2) into a turbidity bottle containing oxalic acid solution and dispersant, mix evenly immediately after the dropping, and measure the system turbidity T with a turbidity meter;

(4) Calculate the grade of rare earth:

Calculate the concentration of rare earth solution according to formula (1),

The formula for calculating the rare earth concentration in the leaching solution is:

C=1.5912T+120.6926 R ² =0.9939 (1)

Calculate the grade of rare earth in rare earth ore according to formula (2),

The formula for calculating rare earth grade is:

In the formula: REO—rare earth grade, mg/kg;

C—the rare earth concentration of the leaching solution, in mg/L;

T—turbidity, in NTU;

V—volume dosage of ammonium sulfate, in mL;

m—the mass of the sample to be tested, in g;

C _w —the moisture of the sample to be tested, in %; the moisture of the sample to be tested is measured by a rapid moisture analyzer;

R ² —Linear correlation coefficient.

Further, in step (1), the mass of the sample to be tested is 50-200 g.

Further, the mass fraction of the ammonium sulfate solution in step (2) is 2%-5%.

Further, the volume of the ammonium sulfate solution in step (2) is 50-200 mL.

Further, the preparation process of the leachate described in step (2) is as follows: folding the filter paper into a funnel shape and placing it in the funnel; placing the funnel on the conical flask; pouring the sample to be tested weighed in step (1). Put it into a transparent plastic bottle, measure 50-200mL of the sample to be tested in the plastic bottle immersed in ammonium sulfate solution, the volume of the ammonium sulfate solution is denoted as V, and shake the sample to be tested with the ammonium sulfate leaching solution for 1-2min until uniform ; Pour the fully mixed sample into the funnel, and drip the leaching solution into the conical flask from the mouth of the funnel.

Further, the concentration of the oxalic acid solution described in step (3) is 0.2 g/L.

Further, in step (3), the dispersing agent is selected from one or more of sodium hexametaphosphate, sodium pyrophosphate and ethanol.

Further, the mass fraction of the dispersant in step (3) is 0.1%-1%.

Further, the turbidity measurement process of step (3) is as follows: pipetting the oxalic acid solution and injecting it into the turbidity bottle; dropping a dispersant in the oxalic acid solution; then pipetting the leaching solution described in step (2) and slowly dripping In the turbidity bottle, during the dropping process, slowly shake to prevent the precipitation from agglomerating; immediately after the dropping, the system turbidity T is measured with a turbidity meter.

Further, the turbidity measurement process of step (3) is as follows: use a pipette to pipette 15mL of oxalic acid solution and inject it into a 20mL turbidity bottle; use a glue tip dropper to drop 2 drops of dispersant in the oxalic acid solution; 5 mL of the leaching solution described in step (2) was slowly dropped into the turbidity bottle by a syringe syringe, and the turbidity of the system was measured by a turbidity meter by shaking slowly during the dropping process to prevent precipitation and agglomeration; Degree T.

Further, formula (1) and formula (2) in step (4) are obtained according to the following method: (1) sampling: take a plurality of samples to be tested, and the specific mass of the samples to be tested is denoted as m; (2) ) Preparation of leaching solution: pour the sample to be weighed in step (1) into a container, immerse the sample to be tested in the container with an ammonium sulfate solution, the volume of the ammonium sulfate solution is denoted as V, and the sample to be tested and The ammonium sulfate leaching solution is shaken for 1-2 minutes until uniform, and the fully mixed sample is filtered to obtain the leaching solution; (3) Turbidity measurement: pipette the oxalic acid solution and inject it into the turbidity bottle; add the dispersant to the oxalic acid solution dropwise After that, the leaching solution described in step (2) was slowly dropped into the turbidity bottle, and during the dropping process, the turbidity was slowly vibrated to prevent the precipitation from agglomerating; T; (4) Concentration measurement: Inductively coupled plasma spectrometer (ICP-OES) was used to measure the concentration of 17 rare earth elements in the leaching solution in step (2), and the total rare earth concentration was accumulated; (5) Fitting: using step (3) ) the measured turbidity is the abscissa, and the concentration measured in step (4) is the ordinate, establish a turbidity-concentration relationship scattergram, and perform linear fitting on the scattergram to obtain formula (1); (6) ) formula correction: measure the moisture of the sample to be tested, perform mass correction on formula (1), and obtain formula (2).

Further, formula (1) and formula (2) in step (4) are obtained according to the following methods: (1) Weighing: adopt a portable electronic scale to weigh a plurality of samples with a mass of 50-200g to be tested. The specific mass of the test sample is recorded as m; (2) leaching: fold the filter paper into a funnel shape and place it in the funnel; place the funnel on the conical flask; pour the sample to be tested weighed in step (1) into a transparent plastic In the bottle, measure 50-200mL of ammonium sulfate solution immersed in the plastic bottle to be tested. The volume of the ammonium sulfate solution is denoted as V. Shake the sample to be tested and the ammonium sulfate leaching solution for 1-2 minutes, and fully The mixed sample is poured into the funnel, and the leaching solution is dropped into the conical flask from the mouth of the funnel; (3) Turbidity measurement: use a pipette to transfer 15mL of oxalic acid solution into a 20mL turbidity bottle; 2 drops of dispersant in the above-mentioned oxalic acid solution; then use a syringe to pipette 5 mL of the leaching solution described in step (2) and slowly drop it into the above-mentioned turbidity bottle, and slowly vibrate during the dropping process to prevent precipitation and agglomeration; after the dropping is completed Shake it up immediately, and use a turbidity meter to measure the turbidity of the system, T; (4) Concentration measurement: use an inductively coupled plasma spectrometer (ICP-OES) to measure the concentration of 17 rare earth elements in the leaching solution in step (2), and accumulate to obtain the total Rare earth concentration; (5) fitting: take the turbidity measured in step (3) as the abscissa and the concentration measured in step (4) as the ordinate, establish a turbidity-concentration relationship scatter diagram, and compare the scatter diagram Perform linear fitting to obtain formula (1); (6) formula correction: measure the moisture of the sample to be tested, and perform mass correction on formula (1) to obtain formula (2); in the formula: REO—rare earth grade, mg/kg; C—the concentration of rare earth in leaching solution, unit mg/L; T—turbidity, unit NTU; V—volume dosage of ammonium sulfate, unit mL; m—mass of sample to be tested, unit _g ; Cw—moisture of sample to be tested, unit %; use a rapid moisture analyzer to measure the moisture of the sample to be tested; R ² —linear correlation coefficient.

Further, the detection tools used in the above method include: ammonium sulfate solution, oxalic acid solution, portable turbidimeter, portable electronic scale, pipette, 20mL turbidity bottle, filter paper, glass funnel, conical flask and measuring cylinder, syringe syringe , plastic head dropper, transparent plastic bottle, rapid moisture analyzer.

The principle of the method of the present invention is:

The principle of using turbidity to convert the concentration of rare earth: The inventor found in research that when a saturated oxalic acid solution is slowly added dropwise to the leaching solution of rare earth ore ammonium sulfate, the rare earth, iron and aluminum and other metal impurities in the leaching solution will produce oxalate precipitation , causing the leaching solution to become turbid, and the turbidity of the system suspension has a certain correlation with the concentration of rare earth. However, the particle size of oxalate precipitation is affected by factors such as feeding method, stirring intensity, temperature, concentration, acidity, precipitation time, etc., resulting in unstable turbidity value of oxalate precipitate. We obtained the method of stabilizing the turbidity value of oxalate through experiments, and established the concentration of ammonium sulfate, the concentration of oxalic acid, the type of dispersant, the concentration of dispersant, the amount of dispersant and the feeding method. Using this method, 500 rare earth ore ammonium sulfate leachate samples were analyzed for oxalate instantaneous turbidity and rare earth concentration, and the relationship between turbidity and rare earth concentration was established by relying on big data. The precipitation state is observed with the naked eye, the accuracy is significantly improved, the rare earth grade can be accurate to 3 decimal places, and the measurement error is within 10%.

Quality correction: Field weathered crust leaching rare earth ores usually contain a certain amount of moisture. The formula corrects the mass of the weighed sample on the basis of a large number of field rare earth ores moisture data, and a rapid moisture analyzer is used to measure the moisture of the sample to be tested.

Compared with the prior art, the present invention has the following beneficial effects:

1. Discovered reagents and methods for stabilizing the turbidity value of oxalate suspensions, established the conversion relationship between the turbidity of rare earth oxalate suspensions and the concentration of rare earths based on the experimental results of big data, and only needs to measure the turbidity in the field Identifying the grade of rare earth is easier and faster than measuring the concentration of rare earth directly;

2. The conversion formula is established based on the turbidity of the oxalate suspension-rare earth concentration in the ammonium sulfate leachate of the natural rare earth ore sample. It is not an artificially prepared rare earth standard solution. The conversion formula already includes the oxalate precipitation of impurity metals, Due to the possible influence of rare earth distribution and solution pH, the obtained rare earth grade is more accurate. It has been verified that the rare earth grade can reach 3 decimal places, and the measurement error is within 10%.

Description of drawings

Fig. 1 is a linear fitting diagram of the turbidity-rare earth concentration of the oxalate suspension of the present invention.

Detailed ways

In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to examples.

Examples 1-30

(1) Weighing the sample: Weigh 50-200 grams of the sample to be tested with a portable electronic scale, and its specific mass is recorded as m; (2) Leaching: fold the filter paper into a funnel shape and place it in the funnel; place the funnel in the cone Pour the sample to be tested weighed in step (1) into a transparent plastic bottle, measure 50-200 mL of ammonium sulfate solution to immerse the sample to be tested in the plastic bottle, the volume of the saturated ammonium sulfate solution is denoted as V, and the Shake the sample to be tested with the ammonium sulfate leaching solution for 2 minutes until uniform; pour the fully mixed sample into the funnel, and drop the leaching solution into the conical flask from the mouth of the funnel. (3) Turbidity measurement: use a pipette to pipette 15mL of oxalic acid solution (0.2g/L) and inject it into a 20mL turbidity bottle; then add 2 drops of dispersant solution (0.1% sodium hexametaphosphate solution); Use a syringe to transfer 5 mL of the leaching solution prepared in step (2) and slowly drop it into the above-mentioned turbidity bottle, shake it up immediately after the dropping, and use a turbidity meter (Shanghai Yuefeng, SGZ-1000BS) to measure the system turbidity , T. (4) Concentration measurement: Inductively coupled plasma spectrometer (ICP-OES) (Agilent, USA, ICPOES730) was used to measure the concentration of 17 rare earth elements in the leaching solution in step (2), and the total rare earth concentration was accumulated; (5) Fitting: Taking the turbidity measured in step (3) as the abscissa and the concentration measured in step (4) as the ordinate, a turbidity-concentration relationship scatter diagram is established, as shown in Figure 1, and a linear simulation is performed on the scatter diagram. Combined, formula (1) is obtained; (6) formula correction: field weathered crust leaching rare earth ore usually contains 30-40% moisture, use a rapid moisture analyzer to measure the moisture of the sample to be tested, and perform mass correction on formula (1), Equation (2) is obtained. (7) Use formula (1) to obtain the calculated concentration of the sample to be tested, and use formula (2) to calculate the rare earth grade of the weathering crust leaching type rare earth ore for rapid identification in the field. The specific measurement data and calculation data of each embodiment are shown in Table 1. Figure 1 shows a linear fitting diagram of the turbidity-rare earth concentration of the oxalate suspension of the present invention. It can be seen from Table 1 that the grades of rare earths calculated by formula (2) in each embodiment and the grades of rare earths obtained by measurement can be in good agreement.

The formula for calculating the rare earth concentration in the leaching solution is:

C=1.5912T+120.6926 R ² =0.9939 (1)

The formula for calculating rare earth grade is:

In the formula: REO—rare earth grade, mg/kg;

C—the rare earth concentration of the leaching solution, in mg/L;

T—turbidity, in NTU;

V—volume dosage of ammonium sulfate, in mL;

m—the mass of the sample to be tested, in g;

C _w —the moisture of the sample to be tested, in %; the moisture of the sample to be tested is measured by a rapid moisture analyzer;

R ² —Linear correlation coefficient.

Table 1. Results for Examples 1-30

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form or substance. It should be pointed out that for those skilled in the art, without departing from the method of the present invention, the Several improvements and supplements can be made, and these improvements and supplements should also be regarded as the protection scope of the present invention. All those skilled in the art, without departing from the spirit and scope of the present invention, can utilize the above-disclosed technical content to make some changes, modifications and equivalent changes of evolution, all belong to the present invention. Equivalent embodiments; at the same time, any modification, modification and evolution of any equivalent changes made to the above embodiments according to the essential technology of the present invention still fall within the scope of the technical solutions of the present invention.

Claims (6)

1. a kind of weathering crust leaching type rare earth ore rare earth grade field rapid identification method, is characterized in that, comprises the following steps: (1) Sampling: Weigh the weathered crust leaching type rare earth ore sample to be tested, and the weight of the sample to be tested is recorded as m; (2) leaching solution preparation: leaching the sample to be weighed in step (1) with ammonium sulfate solution to prepare a leaching solution, and the volume of the ammonium sulfate solution is denoted as V; (3) Turbidity measurement: slowly drop the leaching solution prepared in step (2) into a turbidity bottle containing oxalic acid solution and dispersant, mix evenly immediately after the dropping, and measure the system turbidity T with a turbidity meter; The turbidity measurement process is as follows: pipetting the oxalic acid solution and injecting it into the turbidity bottle; dripping the dispersant in the above-mentioned oxalic acid solution; then pipetting the leaching solution described in step (2) and slowly dropping it into the above-mentioned turbidity bottle, and the dropping process Slowly vibrate in the middle to prevent the precipitation from agglomeration; shake up immediately after the addition is completed, and use a turbidimeter to measure the turbidity T of the system; the concentration of the oxalic acid solution is 0.2g/L; the dispersant is selected from sodium hexametaphosphate and sodium pyrophosphate One or more of; the mass fraction of the dispersant is 0.1%-1%; (4) Calculate the grade of rare earth: Calculate the rare earth concentration of the leaching solution according to formula (1), The formula for calculating the rare earth concentration in the leaching solution is: C=1.5912T+120.6926 R ² =0.9939 (1) Calculate the grade of rare earth in rare earth ore according to formula (2), The formula for calculating rare earth grade is:

In the formula: REO—rare earth grade, mg/kg; C—the rare earth concentration of the leaching solution, in mg/L; T—turbidity, in NTU; V—volume dosage of ammonium sulfate, in mL; m—the mass of the sample to be tested, in g; C _w - the moisture content of the sample to be tested, in %; R ² —Linear correlation coefficient. 2 . The method according to claim 1 , wherein in step (1), the mass of the sample to be tested is 50-200 g. 3 . 3. The method according to claim 1, wherein the mass fraction of the ammonium sulfate solution in step (2) is 2%-5%. 4. The method according to claim 1, wherein the volume of the ammonium sulfate solution in step (2) is 50-200 mL. 5. method according to claim 1, is characterized in that, described in step (2), the preparation process of leachate is as follows: filter paper is folded into funnel shape, is placed in funnel; funnel is placed on Erlenmeyer flask; Pour the sample to be weighed in step (1) into a transparent plastic bottle, measure the sample to be tested in 50-200mL of ammonium sulfate solution immersed in the plastic bottle, the volume of the ammonium sulfate solution is denoted as V, and the sample to be tested is Shake with the ammonium sulfate leaching solution for 1-2 minutes until uniform; pour the fully mixed sample into the funnel, and drip the leaching solution into the conical flask from the mouth of the funnel. 6. method according to claim 1 is characterized in that, formula (1) and formula (2) in step (4) are obtained according to the following method: (1) sampling: take a plurality of samples to be tested, so The specific mass of the sample to be tested is denoted as m; (2) leaching solution preparation: pour the sample to be tested weighed in step (1) into a container, and immerse the sample to be tested in the container with ammonium sulfate solution. The volume of the solution is denoted as V, shake the sample to be tested and the ammonium sulfate solution for 1-2 minutes until uniform, and filter the fully mixed sample to obtain the leachate; (3) Turbidity measurement: pipette the oxalic acid solution and inject it into the turbidity bottle; Add the dispersant dropwise to the oxalic acid solution; then pipette the leaching solution described in step (2) and slowly drop it into the turbidity bottle, and slowly shake during the dropping process to prevent precipitation from agglomeration; shake up immediately after the dropping is completed , using a turbidity meter to measure the turbidity of the system, T; (4) concentration measurement: use an inductively coupled plasma spectrometer to measure the concentration of 17 rare earth elements in the leaching solution in step (2), and accumulate the total rare earth concentration; (5) fitting : take the turbidity measured in step (3) as the abscissa, and the concentration measured in step (4) as the ordinate, establish a turbidity-concentration relationship scattergram, and perform linear fitting on the scattergram to obtain the formula ( 1); (6) Formula correction: measure the moisture of the sample to be tested, perform mass correction on formula (1), and obtain formula (2).

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