Method for determining titanium content in metallurgical material by potentiometric titrator

Abstract

The application discloses a method for determining the content of titanium in metallurgical materials by using a potentiometric titrator, and comprises the following steps: 1) dissolving the metallurgical materials by using a sulfuric acid solution and an ammonium sulfate solution; adding a hydrochloric acid solution and uniformly mixing, then adding aluminum metal and heating until the aluminum metal is completely dissolved, cooling, sealing, and obtaining a solution to be detected; 2) pre-adding part of an ammonium ferric sulfate standard solution to the solution to be detected; adding the ammonium ferric sulfate standard solution to the obtained mixed solution by using a potentiometric titrator and an equivalent point mode until a set equivalent point potential jump value; and calculating the content of titanium in the metallurgical materials w Ti电位滴定 ; 3) fitting the manual titration result w Ti人工滴定 to obtain a determination formula of the content of titanium in the metallurgical materials w Ti电位滴定 . The application can cancel the step of supplementing a protective reagent in the process of potentiometric titration, realizes a full-automatic titration process, and does not need manual intervention; the test accuracy and precision are high, the operation is simple, and the application is suitable for popularization and application.

Description

Technical Field

[0001] This invention belongs to the field of detection and analysis technology, specifically relating to a method for determining the titanium content in metallurgical materials using a potentiometric titrator. Background Technology

[0002] Titanium dioxide, a metallurgical auxiliary material, is a crucial raw material in industrial production, widely used in coatings, plastics, papermaking, inks, cosmetics, synthetic fibers, electronics, ceramics, enamel, welding rods, alloys, and glass industries. Coatings account for the largest share, approximately 60%. Adding titanium dioxide to grain-oriented silicon steel coatings improves their corrosion resistance, oxidation resistance, and heat damage resistance. Typically, magnesium oxide coatings contain a large amount of oxides, which can react with oxygen in the air to produce oxidizing gases, thus causing defects in the silicon steel. Adding titanium dioxide can prevent this reaction, thereby inhibiting oxidation. Furthermore, titanium dioxide can improve the coating's heat resistance by absorbing oxides generated at high temperatures, preventing their evaporation. Therefore, detecting the titanium dioxide content in titanium dioxide is very important.

[0003] Ferrotitanium phosphate (Fe2O3) is used in steelmaking as a deoxidizer, degassing agent, and carbon-sulfur stabilizer. It is a widely used special alloy, added as an alloying element during the steelmaking process to refine the grain structure, fix interstitial elements (C and N), and improve the strength of the steel. With the improvement of steel quality and the increase in variety, the requirements for the quality and variety of ferrotitanium phosphate are becoming increasingly stringent. The international market has a large demand for high-titanium ferrotitanium phosphate, but my country currently generally only produces ordinary medium and low-titanium ferrotitanium phosphate.

[0004] Currently, the determination of titanium content in titanium dioxide or ferrotitanium is mostly done manually using titration. Titration with ferric ammonium sulfate requires an air-isolated environment, typically achieved through nitrogen purging, a vacuum system, or the addition of sodium bicarbonate as a protective solution. Failure to isolate the titration from air can lead to lower test results due to oxidation. Furthermore, the intensity of the endpoint color can easily cause errors in endpoint judgment, thus affecting the test results. Compared to manual titration, automatic potentiometric titrators are unaffected by the color of the solution itself or other interferences, accurately identify the endpoint, reduce human reading errors, and enable automated and continuous measurement. However, traditional potentiometric titration requires the addition of protective reagents (sodium bicarbonate or ammonium sulfate), and the overall results are lower than those obtained through manual titration. Further exploration of efficient methods for determining carbon content using potentiometric titration is of significant research and application value. Summary of the Invention

[0005] The main objective of this invention is to address the problems and shortcomings of traditional methods for determining titanium content, such as the need to add a protective agent to isolate it from air, the susceptibility of the endpoint color to interference, the need to add a protective agent during potentiometric titration, and the resulting low detection values. This invention provides an analytical method for determining the titanium content in metallurgical materials without the need for a protective solution, which allows for a simple, rapid, and accurate determination of the titration endpoint.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for determining the titanium content in metallurgical materials using a potentiometric titrator includes the following steps:

[0008] 1) Add sulfuric acid solution and ammonium sulfate to the metallurgical material, heat to dissolve the metallurgical material, and cool; add hydrochloric acid solution and mix evenly, then add metallic aluminum, stir at low temperature until the metallic aluminum is completely dissolved, cool, seal, and obtain the solution to be tested;

[0009] 2) Add a portion of ferric ammonium sulfate standard solution to the solution to be tested and stir well; using a potentiometric titrator and equivalence point mode, add ferric ammonium sulfate standard solution dropwise to the resulting mixture until the set equivalence point potential jump value is reached, and determine the titration endpoint; calculate the titanium content w in the metallurgical material based on the consumption and concentration of ferric ammonium sulfate standard solution. Ti电位滴定 ;

[0010] 3) The results of manual titration were used. Ti人工滴定 , for w Ti电位滴定 By performing a fitting process, a formula for determining the titanium content in metallurgical materials is obtained.

[0011] In the above scheme, the metallurgical material can be titanium-iron alloy or titanium dioxide, etc.

[0012] In the above scheme, the titanium content in the metallurgical material is 20-80%.

[0013] In the above scheme, the concentration of the sulfuric acid solution is 48-52 vol%, the liquid-solid ratio of the sulfuric acid solution to the metallurgical material is 130-160 mL:1 g, and the mass ratio of ammonium sulfate to the metallurgical material is 58-62:1.

[0014] In the above scheme, the volume concentration of the hydrochloric acid solution is 23-27 vol%, and the liquid-solid ratio of hydrochloric acid to metallurgical material is 155-165 mL:0.1 g.

[0015] In the above scheme, the mass ratio of the metallurgical material to the aluminum is 1:28 to 32.

[0016] In the above scheme, the low-temperature stirring temperature is 75-100℃.

[0017] In the above scheme, the pre-added volume of the ferric ammonium sulfate standard solution is 1 / 40 to 1 / 30 of the volume of the solution to be tested.

[0018] In the above scheme, the Fe in the ferric ammonium sulfate standard solution 3+ The concentration is 0.020–0.030 mol / L.

[0019] In the above scheme, after stirring evenly in step 2), pause and let it stand for more than 2 seconds.

[0020] In the above scheme, the titration parameters of the potentiometric titrator include: signal drift 45-50 mV / min, minimum waiting time 0 s, maximum waiting time 20-26 s, measurement point density 4-6, minimum increment 10-15 μL, maximum increment 9999 μL, minimum rate of adding ferric ammonium sulfate standard solution of 5 mL / min, maximum rate of adding solution of 150-166 μL / min; and the titration time is controlled within 6 min.

[0021] In the above scheme, the set equivalence point potential jump value is 28-30mV.

[0022] In the above scheme, the titanium content w Ti电位滴定 The formula for determining it is:

[0023]

[0024] In the formula, C is the concentration of the ferric ammonium sulfate standard solution, in moles per liter (mol / L); V is the volume of ferric ammonium sulfate standard solution consumed in titrating the sample (including the pre-added concentration of ferric ammonium sulfate standard solution), in milliliters (mL); V0 is the volume of ferric ammonium sulfate standard solution consumed in titrating the blank sample, in milliliters (mL); m is the sample mass, in grams (g); and 79.88 is the molar mass of titanium dioxide, in grams per mole (g / mol).

[0025] In the above scheme, the manual titration step includes: adding a solid protective agent to the test solution obtained in step 1), adding ammonium thiocyanate solution, mixing evenly, and titrating with ferric ammonium sulfate standard solution until the orange-red color does not disappear within 1 minute as the endpoint.

[0026] In the above scheme, the concentration of the ammonium thiocyanate solution is 197-203 g / L, and the liquid-solid ratio of the ammonium thiocyanate solution to the metallurgical material is 48-52 ml: 1 g.

[0027] In the above scheme, the solid protective agent can be sodium bicarbonate or ammonium sulfate, etc.

[0028] In the above scheme, the solid-liquid ratio of the solid protective agent to the solution to be tested is 1g:60-90ml.

[0029] Furthermore, the results of the artificial titration w Ti人工滴定 The formula for determining it is:

[0030]

[0031] In the formula, C is the concentration of the ferric ammonium sulfate standard solution, in moles per liter (mol / L); V is the volume of ferric ammonium sulfate standard solution consumed in titrating the sample, in milliliters (mL); V0 is the volume of ferric ammonium sulfate standard solution consumed in titrating the blank sample, in milliliters (mL); m is the mass of the sample, in grams (g); and 79.88 is the molar mass of titanium dioxide, in grams per mole (g / mol).

[0032] In the above scheme, the formula for determining the titanium content in the metallurgical material is: titanium content = 1.0078 × w Ti电位滴定 +0.02284.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] 1) This invention provides for the first time a method for determining the titanium content in ferrotitanium (titanium dioxide) using an automatic potentiometric titration method. By optimizing the titration steps and conditions, the step of adding a protective reagent (sodium bicarbonate or ammonium sulfate) can be eliminated, realizing a fully automatic titration process without manual intervention.

[0035] 2) The modified potentiometric titration method can effectively replace the traditional manual titration method. It has good test accuracy, high precision, and simple operation, and can meet the needs of daily work in determining the titanium content in metallurgical materials such as titanium dioxide and ferrotitanium. Attached Figure Description

[0036] Figure 1 The result of the manual titration described in the example is w Ti人工滴定 and w Ti电位滴定 The fitting results. Detailed Implementation

[0037] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. These descriptions are only for further illustrating the features and advantages of the present invention, and are not intended to limit the scope of the claims of the present invention.

[0038] In the following examples, the ferric ammonium sulfate standard titration solution used contains C(Fe) 3+ =0.025mol / L. The specific preparation method includes: weighing 12.05g of ferric ammonium sulfate, placing it in a 250mL beaker, adding 100mL of sulfuric acid (H2SO4 to water volume ratio of 1:1) to dissolve it, adding potassium permanganate solution (40g / L) dropwise until a faint red color appears, transferring it to a 1000mL volumetric flask, diluting it to the mark with water, mixing well, and standardizing it after overnight.

[0039] The specific calibration steps include: accurately transferring 25 mL of ferric ammonium sulfate standard solution into a 500 mL Erlenmeyer flask, adding 10 mL of hydrochloric acid (volume ratio of hydrochloric acid to water is 1:5), heating to boiling, and adding stannous chloride solution (60 g / L) dropwise until the test solution turns slightly yellow; quickly adding about 100 mL of water, adding 2 mL of sodium tungstate solution (250 g / L), and adding titanium trichloride solution (concentration of 15 wt%) dropwise until the test solution turns pale blue. After the blue color of the test solution fades, immediately add 15 mL of a sulfuric-phosphoric acid mixture (take 150 mL of sulfuric acid (analytical grade, ρ = 1.84 g / mL) and add... Add 700 mL of water, then add 150 mL of phosphoric acid (analytical grade, ρ = 1.69 g / mL) and mix well. Add 4 drops of sodium diphenylamine sulfonate solution (2 g / L) as an indicator. Titrate with potassium dichromate standard solution (take 1.2258 g of potassium dichromate, dried to constant weight at 118-122℃, in a 250 mL beaker, add about 200 mL of water to dissolve, carefully transfer to a 1000 mL volumetric flask, dilute to the mark, and mix well; c(1 / 6K2Cr2O7) = 0.025 mol / L) until the purple color no longer disappears as the endpoint.

[0040] The concentration of the ferric ammonium sulfate standard solution is calculated according to formula (1):

[0041]

[0042] In the formula: C—concentration of the ferric ammonium sulfate standard titration solution, in moles per liter (mol / L);

[0043] c0 — Concentration of potassium dichromate standard titration solution, in moles per liter (mol / L);

[0044] V2 — The volume of ferric ammonium sulfate standard titration solution transferred, in milliliters (mL);

[0045] V0 — The volume of potassium dichromate standard titration solution consumed during calibration, in milliliters (mL);

[0046] V1 — The volume of potassium dichromate standard titration solution consumed during reagent blank calibration, in milliliters (mL).

[0047] Example 1

[0048] A method for determining the titanium content in metallurgical materials using a potentiometric titrator includes the following steps:

[0049] 1) Preparation of the test solution;

[0050] When the titanium content of the metallurgical material is less than 60.0 wt%, weigh 0.1 g of the sample, accurate to 0.0001 g; when the titanium content is greater than 60.0%, weigh 0.05 g, accurate to 0.0001 g.

[0051] Weigh 0.1000 g (accurate to 0.1 mg) of the sample into a dry 500 mL Erlenmeyer flask, add a small amount of deionized water, and gently shake until it forms an emulsion. Then, slowly heat at ~100°C, add 16 mL of sulfuric acid (50 vol%) and 6.0 g of ammonium sulfate, shake well, and place on a hot plate. First, heat slowly at a low temperature until strong white fumes are produced, and then continue heating until the sample is completely dissolved (sulphuric acid fumes appear at 300-350°C, and the liquid surface is calm). Remove from heat, cool carefully, add 160 mL of 25 vol% hydrochloric acid solution, and shake to make the solution uniform. Add 3 g of aluminum foil, and immediately seal the flask with a Geiger funnel containing a saturated sodium bicarbonate solution. Heat at a low temperature (75-100°C), shaking the Erlenmeyer flask continuously, until the aluminum foil is completely dissolved. Continue boiling for 4-5 minutes to expel the generated hydrogen gas. Remove from heat and cool under running water to room temperature to obtain the test solution (180 mL).

[0052] 2) Remove the Geiger funnel, add 5.5 mL of ferric ammonium sulfate standard solution and mix well. Place it on the designated position on the potentiometric titrator and titrate according to the instructions of the potentiometric titrator until the set equivalence point potential jump value is reached. Determine the titration endpoint. The titration parameters include: signal drift 45-50 mV / min, minimum waiting time 0 s, maximum waiting time 20-26 s, measurement point density 4-6, minimum increment 10-15 μL, maximum increment 9999 μL, maximum liquid addition rate 150-166 μL / min, and the titration time of the potentiometric titrator should be controlled within 6 min.

[0053] The set equivalent point potential jump value is 28-30mV;

[0054] Calculate the titanium content w in the metallurgical material based on the consumption and concentration of the ferric ammonium sulfate standard solution. Ti电位滴定 ;

[0055] 3) Obtain the test solution described in step 1). Remove the Geiger funnel, add 2-3g of solid sodium bicarbonate, add 5.0mL of ammonium thiocyanate solution (200g / L), and quickly titrate with ferric ammonium sulfate standard solution until the orange-red color does not disappear within 1 minute. Calculate the titanium content w in the metallurgical material based on the consumption and concentration of the ferric ammonium sulfate standard solution. Ti人工滴定 Five batches of titanium dioxide and ferrotitanium samples were selected.

[0056] The titanium content of the titanium dioxide standard was analyzed using a potentiometric titrator. The standard sample contained 59.34% titanium (99.0% titanium dioxide). The titanium content of the internally controlled titanium dioxide was analyzed. The titanium content of the ferrotitan standard YSBC15602-2006 was 70.02%, the titanium content of ferrotitan standard No. 66-30 was 29.65%, and the titanium content of ferrotitan standard GSBH42002-92 was 25.18%. Five samples were titrated in parallel, and the average value was used to establish the fitted line equation, i.e., the correction coefficient. The calculation formula for titanium content and the correction coefficient were input.

[0057] The arithmetic mean of the parallel test results is taken as the test result. The parallel test results are controlled at 0.6%. The test results are rounded to two decimal places according to GB / T8170. The reporting results are rounded according to the acceptance standard requirements, referring to the rounding value comparison method of CB / T 8170. The specific test results are shown in Table 1.

[0058] Table 1 Results of titanium content determination by manual titration and potentiometric titration methods

[0059]

[0060] The results of manual titration were used. Ti人工滴定 For w Ti电位滴定 The fitting was performed, and the resulting fitted curve is shown in the figure. Figure 1 The p-value is greater than 0.05, indicating a good fit. Therefore, the formula for determining the titanium content in metallurgical materials is: titanium content = 1.0078 × w Ti电位滴定 +0.02284;

[0061] Application Example 1

[0062] Based on the formula for determining the titanium content in metallurgical materials obtained in Example 1, three batches of titanium dioxide and four batches of ferrotitanium were randomly selected to verify the feasibility of this method. The test results are shown in Table 2.

[0063] Table 2. Titanium content test results obtained by artificial titration and potentiometric titration in the examples.

[0064]

[0065] As can be seen from Table 2, the difference between the titanium content determined by the potentiometric titration method described in this invention and the manual titration method both meet the precision requirements of routine testing.

[0066] Comparative Example 1

[0067] In this experiment, one batch of titanium dioxide samples was randomly selected, and the solution was placed in the air. Titration was performed by potentiometric titration. The specific steps included: using the test liquid system described in Example 1, removing the Geiger funnel, placing it at the designated position on the potentiometric titrator, and performing titration according to the instructions of the potentiometric titrator. Sodium bicarbonate was added as needed during the titration process based on the foaming of the liquid surface. The specific titration analysis results are shown in Table 3.

[0068] Table 3. Comparison of different time consumption for determining titanium content using the potentiometric titration method described in this invention and the traditional potentiometric titration method.

[0069] serial number This invention relates to potentiometric titration of titanium content (%) Comparative titration of titanium content (%) over 7 minutes Comparative titration of titanium content (%) over 8 minutes 1 58.81 58.05 58.01 2 58.93 58.12 57.88 3 58.71 57.93 57.82 4 58.90 57.87 57.79 5 58.86 57.92 57.92 6 58.83 57.86 57.76 mean 58.84 57.96 57.86 Standard deviation 0.08 0.10 0.09 RSD 0.13 0.18％ 0.16％

[0070] This invention is not limited to the embodiments described above. Those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention. Contents not described in detail in this specification are prior art known to those skilled in the art.

Claims

1. A method for determining the titanium content in metallurgical materials using a potentiometric titrator, characterized in that, Includes the following steps: 1) Add sulfuric acid solution and ammonium sulfate to the metallurgical material, heat to dissolve the metallurgical material, and then cool; Add hydrochloric acid solution and mix well. Then add metallic aluminum and stir at low temperature until the metallic aluminum is completely dissolved. Cool, seal, and obtain the solution to be tested. 2) Add a portion of ferric ammonium sulfate standard solution to the solution to be tested and stir well; using a potentiometric titrator and equivalence point mode, add ferric ammonium sulfate standard solution dropwise to the resulting mixture until the set equivalence point potential jump value is reached, and determine the titration endpoint; calculate the titanium content w in the metallurgical material based on the consumption and concentration of ferric ammonium sulfate standard solution. Ti电位滴定 ; 3) The results of manual titration were used. Ti人工滴定 , for w Ti电位滴定 By performing a fitting, a formula for determining the titanium content in metallurgical materials is obtained; The concentration of the sulfuric acid solution is 48-52 vol%, and the liquid-solid ratio of the sulfuric acid solution to the metallurgical material is 130-160 ml: 1 g; the mass ratio of ammonium sulfate to the metallurgical material is 58-62: 1; the concentration of the hydrochloric acid solution is 23-27 vol%, and the liquid-solid ratio of the hydrochloric acid solution to the metallurgical material is 155-165 ml: 0.1 g. The mass ratio of the metallurgical material to metallic aluminum is 1:28~32; Manual titration results w Ti人工滴定 The detection steps include: adding a solid protective agent to the solution to be tested obtained in step 1), adding ammonium thiocyanate solution, mixing evenly, and titrating with ferric ammonium sulfate standard solution until the orange-red color does not disappear within 1 minute, which is the titration endpoint.

2. The method according to claim 1, characterized in that, The metallurgical material is ferro-titanium alloy or titanium dioxide.

3. The method according to claim 1, characterized in that, The pre-added volume of the ferric ammonium sulfate standard solution is 1 / 40 to 1 / 30 of the volume of the solution to be tested.

4. The method according to claim 1, characterized in that, Fe in ferric ammonium sulfate standard solution 3+ The concentration is 0.020~0.030 mol / L.

5. The method according to claim 1, characterized in that, The minimum rate at which the potentiometric titrator adds the ferric ammonium sulfate standard solution is 5 mL / min, and the maximum rate is 150~166 μL / min; the addition time is controlled within 6 min.

6. The method according to claim 1, characterized in that, The set equivalent point potential jump value is 28~30mV.

7. The method according to claim 1, characterized in that, Manual titration results w Ti人工滴定 The detection steps include: adding a solid protective agent to the solution to be tested obtained in step 1), adding ammonium thiocyanate solution, mixing evenly, and titrating with ferric ammonium sulfate standard solution until the orange-red color does not disappear within 1 minute, which is the titration endpoint.

8. The method according to claim 1, characterized in that, The formula for determining the titanium content in the metallurgical material is: titanium content = 1.0078 × w Ti电位滴定 +0.02284.

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