Preparation method of quality control sample

Abstract

The invention provides a preparation method of a quality control sample, and relates to the technical field of material analysis and detection, the component concentration of the quality control sample obtained by the preparation method can be kept in a quality control sample concentration error range for a long time, and the quality control sample can be used as a quality control sample for detecting main content components of a solution in the process of producing aluminum oxide by a Bayer method through a potentiometric titrator.

Description

[Technical field]

[0001] The invention relates to the technical field of material analysis and detection, and in particular to a method for preparing a quality control sample. [Background technology]

[0002] At present, in the process of producing alumina by the Bayer process, the technology for analyzing the main content components of the solution is generally to use a potentiometric titration instrument to detect caustic soda, total alkali and alumina. A potentiometric titrator is an instrument that uses the potentiometric titration method to determine the titration end point by measuring the potential change during the titration process. It can automatically titrate, automatically determine the end point, and automatically calculate the analysis results. It is easy to use, fast and accurate.

[0003] In the process of using a potentiometric titrator to detect the main content of a solution, in order to detect the stability and accuracy of the instrument's test operation, instrument analysis quality control samples are usually used for testing and determination. By testing the known concentration of the quality control sample to see if the instrument's curve is standard and available, it is also possible to test whether the data is within the error range of the quality control sample concentration to verify the accuracy of the instrument. Only on this basis can the accuracy and stability of the instrument analysis be further guaranteed. This requires that the composition results of the quality control sample must be very stable, and the data value stability error is within a reasonable range. It can also be said that the composition results of the quality control sample are very stable under specific storage conditions over a long period of time.

[0004] Therefore, how to prepare quality control samples with very stable composition results has become a very important link in instrument detection and analysis. [Summary of the invention]

[0005] In view of this, the object of the present invention is to provide a method for preparing a quality control sample, wherein the concentration of the quality control sample components obtained by the method can be maintained within the quality control sample concentration error range for a long time, and can be used as a quality control sample for detecting the main content components of the solution in the Bayer process of producing alumina by a potentiometric titrator.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A method for preparing a quality control sample comprises the following steps:

[0008] (1) In the Bayer process of alumina production, taking a circulating mother liquor, filtering it, and cooling it to room temperature to obtain a solution A for standby use;

[0009] (2) Sodium tartrate is placed in a volumetric flask, and deionized water is added thereto to prepare a sodium tartrate solution, which is Solution B and is set aside;

[0010] (3) dissolving sodium hydroxide with deionized water to obtain a sodium hydroxide solution with a concentration of 4-6 mol / L, which is solution C and is used for standby use;

[0011] (4) Add solution C to solution A until the R P If the value is less than 0.5, solution D is obtained and set aside;

[0012] (5) Solution B and solution D are mixed, the resulting solution is allowed to stand for a period of time, and then the solution is filtered to obtain the quality control sample.

[0013] In the present invention, further, in the step (1), the circulating mother liquor is filtered through qualitative filter paper (medium speed).

[0014] In the present invention, further, the concentration of the sodium tartrate solution in step (2) is 25%. Specifically, 250 g of sodium tartrate is placed in a volumetric flask, and deionized water is added to fill the volumetric flask to a mark of 1000 mL to prepare the sodium tartrate solution.

[0015] In the present invention, further, in the step (3), the concentration of the sodium hydroxide solution is 5 mol / L.

[0016] In the present invention, further, the mixing ratio of solution B and solution D in step (5) is 1:1.

[0017] In the present invention, further, the solution in step (5) is placed for 5-6 weeks.

[0018] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0019] 1. The present invention provides a method for preparing a quality control sample. The concentration of the quality control sample obtained by the preparation method can be kept within the error range of the quality control sample concentration for a long time, and can be used as a quality control sample for detecting the main content components of the solution in the process of producing alumina by the Bayer process using a potentiometric titrator. In the preparation process, the R of the mother solution A is adjusted. P The value is less than 0.5, which can increase the OH content in the solution. - The concentration of ions is controlled to ensure that aluminum ions in the solution do not precipitate and precipitate, and the stability of the solution is ensured. In addition, solution B and solution D are mixed and then placed before filtering, in order to allow the solution to have a stable process, so that a solution analysis monitoring sample similar to a solid standard sample is obtained. The method proposed in the present application includes diluting the circulating mother liquor with a sodium tartrate solution and increasing the NaOH concentration in the circulating mother liquor. The solution obtained after the treatment remains stable for a certain period of time, and the content of each component changes little, within the production allowable difference range. [Specific implementation method]

[0020] The following embodiments may help those skilled in the art to more fully understand the present invention, but shall not limit the present invention in any way.

[0021] Example 1

[0022] This embodiment provides a method for preparing a quality control sample, which specifically includes the following steps:

[0023] (1) In the Bayer process of alumina production, the circulating mother liquor is filtered using qualitative filter paper (medium speed), and cooled to room temperature to obtain solution A for standby use;

[0024] (2) Sodium tartrate is placed in a volumetric flask, and deionized water is added thereto to prepare a sodium tartrate solution with a concentration of 25%, which is referred to as solution B and is set aside;

[0025] (3) dissolving sodium hydroxide with deionized water to obtain a sodium hydroxide solution with a concentration of 4 mol / L, which is solution C and is ready for use;

[0026] (4) Add solution C to solution A until the R P If the value is less than 0.5, solution D is obtained and set aside;

[0027] (5) Solution B and solution D are mixed in a volume ratio of 1:1, and the resulting solution is left for 5 weeks. The solution is then filtered to allow the solution to stabilize, thereby obtaining the quality control sample (a solution analysis monitoring sample similar to a solid standard sample).

[0028] Among them, N k is the caustic soda concentration of sodium aluminate solution (g / L); N T is the total alkali concentration of sodium aluminate solution (g / L); AO is the aluminum oxide concentration of sodium aluminate solution (g / L);

[0029] Where R P The value is obtained by analyzing the N of solution A. k , N T Calculated after AO;

[0030] The specific calculation method (formula) is: R P =AO / N k

[0031] Example 2

[0032] This embodiment provides a method for preparing a quality control sample, which specifically includes the following steps:

[0033] (1) In the Bayer process of alumina production, the circulating mother liquor is filtered using qualitative filter paper (medium speed), and cooled to room temperature to obtain solution A for standby use;

[0034] (2) Sodium tartrate is placed in a volumetric flask, and deionized water is added thereto to prepare a sodium tartrate solution with a concentration of 25%, which is referred to as solution B and is set aside;

[0035] (3) dissolving sodium hydroxide with deionized water to obtain a sodium hydroxide solution with a concentration of 5 mol / L, which is solution C and is ready for use;

[0036] (4) Add solution C to solution A until the R P If the value is less than 0.5, solution D is obtained and set aside;

[0037] (5) Solution B and solution D are mixed in a volume ratio of 1:1, and the resulting solution is left for 5 weeks. The solution is then filtered to allow the solution to stabilize, thereby obtaining the quality control sample (a solution analysis monitoring sample similar to a solid standard sample).

[0038] Among them, N k is the caustic soda concentration of sodium aluminate solution (g / L); N T is the total alkali concentration of sodium aluminate solution (g / L); AO is the aluminum oxide concentration of sodium aluminate solution (g / L);

[0039] Where R P The value is obtained by analyzing the N of solution A. k , N T Calculated after AO;

[0040] The specific calculation method (formula) is: R P =AO / N k

[0041] Example 3

[0042] This embodiment provides a method for preparing a quality control sample, which specifically includes the following steps:

[0043] (1) In the Bayer process of alumina production, the circulating mother liquor is filtered using qualitative filter paper (medium speed), and cooled to room temperature to obtain solution A for standby use;

[0044] (2) Sodium tartrate is placed in a volumetric flask, and deionized water is added thereto to prepare a sodium tartrate solution with a concentration of 25%, which is referred to as solution B and is set aside;

[0045] (3) dissolving sodium hydroxide with deionized water to obtain a sodium hydroxide solution with a concentration of 6 mol / L, which is solution C and is ready for use;

[0046] (4) Add solution C to solution A until the R P If the value is less than 0.5, solution D is obtained and set aside;

[0047] (5) Solution B and solution D are mixed in a volume ratio of 1:1, and the resulting solution is left for 6 weeks. The solution is then filtered to allow the solution to stabilize, thereby obtaining the quality control sample (a solution analysis monitoring sample similar to a solid standard sample).

[0048] Where R P The value is obtained by analyzing the N of solution A. k , N T Calculated after AO;

[0049] Among them, N k is the caustic soda concentration of sodium aluminate solution (g / L); N T is the total alkali concentration of sodium aluminate solution (g / L); AO is the aluminum oxide concentration of sodium aluminate solution (g / L);

[0050] The specific calculation method (formula) is: R P =AO / N k

[0051] Test example

[0052] Five or more skilled analysts and engineering technicians shall, under the same conditions, analyze the AO and N T 、N K The content is measured, and the average value of the results is taken to obtain a value close to the true value, which is used as the standard value of the monitoring sample.

[0053] The results are shown in Table 1:

[0054] Table 1 Monitoring solution setting

[0055]

[0056]

[0057] In addition, during the storage of the quality control sample, we conducted a 6-week follow-up test on the solution and obtained the data results in Table 2.

[0058] Table 2 Monitoring solution stability test data

[0059] time AO(g / l) <![CDATA[N K (g / l)]]> <![CDATA[N T (g / l)]]> <![CDATA[R P ]]> before placing 85.5 180.0 187.8 0.475 Leave for 1 week 85.9 181.0 188.6 0.480 Leave for 2 weeks 85.7 181.0 188.7 0.473 Leave for 3 weeks 85.7 180.0 189.7 0.476 Place for 4 weeks 85.9 179.0 188.6 0.480 Place for 5 weeks 86.0 180.0 189.5 0.478 Place for 6 weeks 85.9 180.0 189.6 0.477 Allowable difference 1.0 2.5 2.0 ―

[0060] From the above table, it can be seen that within 6 weeks, the AO and N T 、N K The content change is within the allowable range, and the stability of the solution is guaranteed. In summary, it is feasible to use this solution as a monitoring sample to control the quality of the sodium aluminate solution.

[0061] This application is carried out by N k , N T , AO, R P The measured and analyzed data are processed to obtain an average value. This can be used as a monitoring solution to monitor the quality of the analyst or team, and the analysis quality can be judged based on the measured results. The analysis results of several shifts can also be plotted into a curve, and the analysis quality can be known based on the curve drift, and corresponding adjustments can be made. After actual application in production, the effect is very good and is suitable for actual production.

[0062] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A method for preparing a quality control sample, characterized in that: The following steps are involved: (1) In the Bayer process of alumina production, taking a circulating mother liquor, filtering it, and cooling it to room temperature to obtain a solution A for standby use; (2) Sodium tartrate is placed in a volumetric flask, and deionized water is added thereto to prepare a sodium tartrate solution, which is Solution B and is set aside; (3) dissolving sodium hydroxide with deionized water to obtain a sodium hydroxide solution with a concentration of 4-6 mol / L, which is solution C and is used for standby use; (4) adding solution C to solution A until the RP value of solution A is less than 0.5, thereby obtaining solution D for later use; (5) Solution B and solution D are mixed, the resulting solution is allowed to stand for a period of time, and then the solution is filtered to obtain the quality control sample.

2. The method according to claim 1, characterized in that In the step (1), the circulating mother liquor is filtered through qualitative filter paper.

3. The method according to claim 1, characterized in that The concentration of the sodium tartrate solution in step (2) is 25%.

4. The method according to claim 1, characterized in that: In the step (3), the concentration of the sodium hydroxide solution is 5 mol / L.

5. The method according to claim 1, characterized in that In the step (5), the mixing ratio of solution B and solution D is 1:

1.

6. The method according to claim 1, characterized in that The solution in step (5) is left for 5-6 weeks.

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