Method for measuring zinc element in zinc concentrate

Abstract

The invention discloses a zinc concentrate zinc element determination method, which comprises: respectively adding ammonium fluoride, hydrobromic acid and hydrochloric acid into a concentrate powder sample, dissolving to a clear amount on a low-temperature electric heating plate, adding nitric acid, dissolving to a dry state, adding ammonium chloride, and boiling; cooling the decomposed sample to room temperature, adding ammonia water, absolute ethyl alcohol and potassium fluoride for dissolving, filtering the sample, adding ascorbic acid, sodium thiosulfate, potassium iodide and xylenol orange, adjusting the pH value, adding an acetic acid-sodium acetate buffer solution, titrating by adopting an ethylenediamine tetraacetic acid standard titration solution, and calculating the final zinc content. According to the method, the zinc ions can be fully dissolved through hydrochloric acid and nitric acid, the ammonia water is used for complexing the zinc ions, potassium fluoride, sodium thiosulfate, ammonium fluoride and hydrobromic acid are used for removing impurity interference, the ammonia water is rapidly complexed with the zinc ions through the volatilization effect of absolute ethyl alcohol, cadmium is masked through potassium iodide, and rapid determination of the zinc element is achieved through one-time precipitation separation. The test labor intensity is reduced, and the test detection analysis efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of zinc element detection, and in particular to a method for determining zinc element in a concentrate. Background Art

[0002] Zinc concentrate is generally produced by crushing, ball milling, froth flotation and other processes of lead-zinc ore or zinc-containing ore to produce an ore with a high zinc content that meets national standards. Zinc is a commonly used non-ferrous metal, and zinc concentrate is the main raw material for producing metallic zinc, zinc compounds, etc. The zinc content generally ranges from 40.00% to 55.00%.

[0003] In the field of zinc concentrate analysis and testing, the main methods for determining zinc include disodium ethylenediaminetetraacetic acid titration, X-ray fluorescence spectroscopy, potentiometric titration, etc.

[0004] The above method for determining zinc element has a cumbersome operation process.

[0005] GB / T8151.1-2012 "Chemical Analysis Methods for Zinc Concentrates - Determination of Zinc Content" adopts the disodium ethylenediaminetetraacetic acid titration method. First, this method uses ammonium persulfate to mask iron, hydrochloric acid to volatilize and remove sulfur, potassium fluoride to mask aluminum, magnesium and other elements, sodium thiosulfate to mask copper, and drops xylenol orange as the indicator. It is titrated with a standard solution of disodium ethylenediaminetetraacetic acid until the test solution turns bright yellow as the end point. However, due to the high sulfur and iron content in zinc concentrate, iron hydroxide precipitates are easily formed during the ammonia washing process, and the result is low. Secondly, this method uses ammonia concentration for secondary precipitation. Incomplete washing during the secondary washing process will lead to low results. The analysis process is complicated and the process is long, which is not conducive to actual production use. The titration result is the total amount of zinc and cadmium, which needs to be determined by atomic absorption and then deducted from the zinc amount.

[0006] X-ray fluorescence spectrometry uses matrix matching, and the element content of each production process is different. The curve of the tablet method is difficult to establish, and the melting time of the fusion method is long, which is not conducive to large-scale detection and analysis. Potentiometric titration solves the color change at the end of the titration, but the processing still uses the national standard method for a long time. The above methods are not conducive to batch processing of samples. Summary of the invention

[0007] The purpose of the present invention is to provide a method for determining zinc in concentrate, aiming to solve the problems of complicated current detection methods, low detection efficiency and poor accuracy in determining zinc in high-sulfur and high-iron environments.

[0008] The technical solution of the present invention is:

[0009] A method for determining tin in concentrate, comprising:

[0010] Grind and reduce the concentrate sample to be measured to obtain a 200-mesh powder concentrate sample, weigh the concentrate powder sample into a beaker, add ammonium fluoride, hydrobromic acid, and hydrochloric acid to the powder concentrate powder sample, respectively, and cover the surface with a watch glass on a low-temperature electric hot plate to dissolve until the amount is clear;

[0011] Add nitric acid and continue to dissolve on a high-temperature electric hot plate until completely dry, then add ammonium chloride and boil; wash the decomposed sample with distilled water and cool to room temperature;

[0012] Add ammonia water, anhydrous ethanol and potassium fluoride to dissolve, transfer to a volumetric flask, and shake to volume;

[0013] Filter the sample with filter paper, remove the middle solution, add ascorbic acid, sodium thiosulfate and xylenol orange, adjust the pH with dilute hydrochloric acid, and add acetic acid-sodium acetate buffer solution;

[0014] Use ethylenediaminetetraacetic acid standard titration solution for titration and calculate the final zinc content.

[0015] Optionally, in some embodiments, the ore sample to be measured is ground and reduced to obtain a 200-mesh powdered ore sample, and 0.2000 g of the sample is weighed into a beaker for later use; 2 mL of 500 g / L ammonium fluoride, 10 mL of hydrobromic acid, and 15 mL of hydrochloric acid are respectively transferred into the weighed sample beaker, and the sample is placed on a low-temperature electric hot plate to dissolve until clear.

[0016] Optionally, in some embodiments, the powdered concentrate sample to be tested and ammonium fluoride, hydrobromic acid and hydrochloric acid are placed on a low-temperature electric heating plate at a temperature of 60° C., covered with a watch glass, and the dissolution process is continued until the brown smoke fades and the solution becomes clear.

[0017] Optionally, in some embodiments, 5 mL of nitric acid is added to the dissolved sample and placed on a high-temperature hot plate at 300° C. to dissolve until 2 mL remains.

[0018] Optionally, in some embodiments, 20 mL of ammonium chloride with a concentration of 200 g / L is added to the beaker and the beaker is placed on a high-temperature electric hot plate and boiled for 1 min. The watch glass and the wall of the beaker are washed 3 times with distilled water and cooled to room temperature.

[0019] Optionally, in some embodiments, after the sample in the beaker is cooled to room temperature, 20 mL of aqueous ammonia, 10 mL of anhydrous ethanol, and 10 mL of a 200 g / L potassium fluoride solution are added respectively, and the mixture is transferred to a 100 mL volumetric flask, fixed to volume, and shaken well.

[0020] Optionally, in some embodiments, the middle portion of the sample that has been fixed to volume and shaken is filtered using filter paper into a 25 mL volumetric flask and then transferred to a beaker.

[0021] Optionally, in some embodiments, 0.2 g of ascorbic acid, 5 mL of 150 g / L sodium thiosulfate, 2 g of potassium iodide, 2 drops of 5 g / L xylenol orange are added to a beaker, the solution is adjusted to bright yellow using (1+1) hydrochloric acid, and 20 mL of acetic acid-sodium acetate buffer solution (pH 5.5) is added to obtain a solution to be titrated.

[0022] Optionally, in some embodiments, the ethylenediaminetetraacetic acid standard titration solution has a concentration of 0.01 moL / L.

[0023] The technical solution provided by the present invention has the following beneficial effects:

[0024] The invention effectively overcomes the shortcomings of the prior art in the field of zinc concentrate analysis and detection, such as cumbersome zinc element determination operation process, complicated analysis process, long process, difficult to ensure accuracy, and disadvantageous for large-scale detection and analysis. The invention can grind the sample and fully dissolve it with hydrochloric acid and nitric acid, use ammonia water to complex zinc ions, use potassium fluoride, sodium thiosulfate, ammonium fluoride and hydrobromic acid to remove impurity interference, use the volatilization effect of anhydrous ethanol to make ammonia water quickly complex zinc ions, and realize rapid determination of zinc element by one-time precipitation and separation, thereby reducing the labor intensity of laboratory tests and improving the efficiency of laboratory tests and analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic flow chart of a method for determining zinc in a zinc concentrate sample according to an embodiment of the present invention;

[0026] Figure 2 It is another schematic diagram of the implementation process of the method for determining the zinc element in a zinc concentrate sample shown in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0028] In view of the above problems, the embodiment of the present invention provides a method for determining the zinc element in zinc concentrate, which can grind the sample and dissolve it with hydrochloric acid and nitric acid, use ammonia water to complex zinc ions, use potassium fluoride, sodium thiosulfate, ammonium fluoride, and hydrobromic acid to remove impurity interference, use the volatilization effect of anhydrous ethanol to make ammonia water quickly complex zinc ions, and achieve rapid determination of zinc element by precipitation and separation, thereby reducing the labor intensity of laboratory tests and improving the efficiency of laboratory tests and analysis. The technical scheme of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings.

[0029] Example 1

[0030] like Figure 1 As shown, a method for determining zinc in zinc concentrate comprises:

[0031] S101, grind and reduce the concentrate sample to be measured to obtain a 200-mesh powdered concentrate sample, weigh the powdered concentrate sample into a beaker, add ammonium fluoride, hydrobromic acid, and hydrochloric acid to the concentrate powder sample, respectively, and cover with a watch glass on a low-temperature electric hot plate to dissolve until the amount is clear;

[0032] Specifically, the ore sample to be measured is ground and reduced to obtain a 200-mesh powdered ore sample, and 0.2000 g of the sample is weighed into a beaker for later use; 2 mL of 500 g / L ammonium fluoride, 10 mL of hydrobromic acid, and 15 mL of hydrochloric acid are respectively transferred into the weighed sample beaker, and the concentrate sample to be measured and ammonium fluoride, hydrobromic acid, and hydrochloric acid are placed on a low-temperature electric heating plate at a temperature of 60°C, covered with a watch glass, and the dissolution process is carried out until the brown smoke fades and the solution becomes clear.

[0033] S102, adding nitric acid and dissolving on a high temperature electric hot plate until completely dry;

[0034] Specifically, 5 mL of nitric acid was added to the dissolved sample and placed on a high-temperature electric hot plate at 300° C., and dissolved until 2 mL remained.

[0035] S103, adding ammonium chloride and boiling; washing the decomposed sample with distilled water and cooling to room temperature;

[0036] Specifically, 20 mL of ammonium chloride with a concentration of 200 g / L was added into the beaker, and the beaker was placed on a high-temperature electric hot plate and boiled for 1 min. The watch glass and the wall of the beaker were washed with distilled water for 3 times, and the beaker was cooled to room temperature.

[0037] S104, add ammonia water, anhydrous ethanol and potassium fluoride to dissolve, transfer to a volumetric flask, and shake to volume;

[0038] Specifically, after the sample in the beaker is cooled to room temperature, 20 mL of ammonia water, 10 mL of anhydrous ethanol, and 10 mL of a 200 g / L potassium fluoride solution are added respectively, and the mixture is transferred to a 100 mL volumetric flask, fixed to volume, and shaken well.

[0039] S105, filter the sample with filter paper, remove the middle solution, add ascorbic acid, sodium thiosulfate, potassium iodide and xylenol orange, adjust the pH with dilute hydrochloric acid, and add acetic acid-sodium acetate buffer solution;

[0040] Specifically, the middle liquid of the sample that has been fixed to volume and shaken is filtered into a 25 mL volumetric flask using filter paper and transferred to a beaker. 0.2 g of ascorbic acid, 5 mL of sodium thiosulfate with a concentration of 150 g / L, 2 drops of 5 g / L xylenol orange are added to the beaker respectively, the solution is adjusted to bright yellow using (1+1) hydrochloric acid, and 20 mL of acetic acid-sodium acetate buffer solution (pH value is 5.5) is added to obtain a solution to be titrated.

[0041] S106. Use ethylenediaminetetraacetic acid standard titration solution to titrate and calculate the final zinc content.

[0042] Specifically, the ethylenediaminetetraacetic acid standard titration solution has a concentration of 0.01 mol / L.

[0043] Example 2

[0044] like Figure 2 As shown, a method for determining zinc in zinc concentrate comprises:

[0045] S201. Grind and reduce the ore sample to be measured to obtain a 200-mesh powdered ore sample, and weigh 0.2000 g of the sample into a beaker for later use.

[0046] S202. Transfer 2 mL of 500 g / L ammonium fluoride, 10 mL of hydrobromic acid and 15 mL of hydrochloric acid to the weighed sample beaker respectively. Place the concentrate sample to be tested and the ammonium fluoride, hydrobromic acid and hydrochloric acid on a low-temperature electric heating plate at 60°C, cover with a watch glass and dissolve until the brown smoke disappears and the solution becomes clear.

[0047] S203. Add 5 mL of nitric acid to the dissolved sample and place it on a high-temperature electric hot plate at 300° C. to dissolve until 2 mL remains.

[0048] S204. Add 20 mL of ammonium chloride with a concentration of 200 g / L into the beaker and continue to boil it on a high-temperature electric hot plate for 1 min. Wash the watch glass and the wall of the beaker with distilled water for 3 times and cool it to room temperature.

[0049] S205. After the sample in the beaker has cooled to room temperature, add 20 mL of aqueous ammonia, 10 mL of anhydrous ethanol, and 10 mL of 200 g / L potassium fluoride solution, respectively, transfer to a 100 mL volumetric flask, make up to volume, and shake well.

[0050] S206, the sample that is constant volume and shaken is taken and the middle liquid is filtered to a 25mL volumetric flask using filter paper and transferred to a beaker. 0.2g ascorbic acid, 5mL sodium thiosulfate with a concentration of 150g / L, 2g potassium iodide, 2 drops of 5g / L xylenol orange, (1+1) hydrochloric acid adjustment solution to bright yellow are added to the beaker respectively, and 20mL acetic acid-sodium acetate buffer solution (pH value is 5.5) is added to obtain a solution to be titrated.

[0051] S207, specifically ethylenediaminetetraacetic acid standard titration solution, the concentration of the standard titration solution is 0.01moL / L.

[0052] Comparative Example 1

[0053] Using the GB / T8151.1-2012 method, weigh about 0.2000g of sample, dissolve it with hydrochloric acid, nitric acid and sulfuric acid, precipitate and separate coexisting elements such as iron, manganese and lead, add masking agent to the filtrate to mask a small amount of interfering elements, and titrate with Na2EDTA standard solution in acetic acid-sodium acetate buffer solution with pH 5-6 and xylenol orange as indicator. The result is the total amount of zinc and cadmium. Deduct the cadmium amount to get the zinc amount.

[0054]

[0055] As can be seen from the above table, compared with the national standard GB / T8151.1-2012, the results of the methods of Example 1 and Example 2 are within the error range. Ammonia water is used for primary precipitation, and potassium iodide is used to mask cadmium, and the amount of zinc can be directly titrated and calculated. This method has high working efficiency and is easy to operate. It reduces the interference of titration due to the high iron content of zinc concentrate, and also avoids the low result caused by unfamiliarity with the secondary precipitation process.

[0056] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terms used herein are selected to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for determining zinc in zinc concentrate, characterized in that: include: Step 1, grind and reduce the concentrate sample to be measured to obtain a powder concentrate sample, weigh the powder concentrate sample into a beaker, add ammonium fluoride, hydrobromic acid, and hydrochloric acid respectively, and place it on a low-temperature electric hot plate to dissolve and clarify; Step 2: Add nitric acid to the melted and clear sample and place it on a high-temperature electric hot plate to continue dissolving until it is completely dry. Add ammonium chloride and boil it. Wash the cup wall with water. Cool it to room temperature. Add ammonia water, anhydrous ethanol, and potassium fluoride. Transfer it to a volumetric flask, shake it to volume, filter the sample with filter paper, and transfer it to a beaker. Step 3, pipetting the middle solution, adding ascorbic acid, sodium thiosulfate, potassium iodide and xylenol orange, adjusting the pH with dilute hydrochloric acid, adding acetic acid-sodium acetate buffer solution, and obtaining a solution sample to be tested; Step 4, titrating with ethylenediaminetetraacetic acid standard titration solution until bright yellow, and calculating the zinc content in the solution sample to be tested according to the titration volume and the concentration of the standard solution.

2. The measuring method according to claim 1, characterized in that In step 1, the powder concentrate sample is in the form of 200 mesh powder.

3. The measuring method according to claim 1, characterized in that In step 1, the powder concentrate sample is weighed into a beaker, and ammonium fluoride, hydrobromic acid, and hydrochloric acid are added respectively, and the beaker is placed on a low-temperature electric hot plate to dissolve and clarify, including: Weigh 0.2000g of powdered concentrate sample into a beaker for later use; Pipette 2 mL of 500 g / L ammonium fluoride, 10 mL of hydrobromic acid, and 15 mL of hydrochloric acid into the weighed sample beaker, and place on a low-temperature electric hot plate at 60°C to dissolve until clear.

4. The measuring method according to claim 1, characterized in that In step 2, the step of adding nitric acid and placing the mixture on a high-temperature electric hot plate to continue dissolving comprises: Add 5 mL of nitric acid to the dissolved sample and place it on a high-temperature electric hot plate at 300°C to dissolve until 2 mL remains.

5. The measuring method according to claim 1, characterized in that In step 2, the adding of ammonium chloride and boiling comprises: Add 20 mL of ammonium chloride with a concentration of 200 g / L into the beaker and continue to boil on a high-temperature electric hot plate for 1 min. Wash the watch glass and the wall of the beaker three times with distilled water and cool to room temperature.

6. The measuring method according to claim 1, characterized in that In step 2, the adding of ammonia water, anhydrous ethanol and potassium fluoride comprises: After the sample in the beaker has cooled to room temperature, add 20 mL of aqueous ammonia, 10 mL of anhydrous ethanol, and 10 mL of 200 g / L potassium fluoride solution, transfer to a 100 mL volumetric flask, make up to volume, and shake well.

7. The measuring method according to claim 1, characterized in that In step 2, transferring the sample filtered by filter paper to a beaker comprises: Take the middle liquid of the sample that has been adjusted to volume and shaken well and filter it into a 25mL volumetric flask using filter paper.

8. The measuring method according to claim 1, characterized in that Step 3 also includes: 0.2 g of ascorbic acid, 5 mL of 150 g / L sodium thiosulfate, 2 g of potassium iodide, 2 drops of 5 g / L xylenol orange were added to a beaker, the solution was adjusted to bright yellow with hydrochloric acid, and 20 mL of acetic acid-sodium acetate buffer solution was added to obtain a solution to be titrated; the pH value of the buffer solution was 5.

5.

9. The determination method according to any one of claims 1 to 8, characterized in that In step 4, the mass concentration of the ethylenediaminetetraacetic acid standard titration solution is 0.01 mol / L.

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