Method for measuring free acid concentration in acid liquid

A free acid and concentration technology, applied in the direction of material electrochemical variables, can solve problems such as ambiguity and errors, interference with end point judgment, cumbersome manual titration operations, etc., and achieve the effect of increasing accuracy

Inactive Publication Date: 2012-09-19
武钢集团有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Manual titration is cumbersome and time-consuming
During the titration, as the pH rises during the titration process, the iron ions in the acid solution tend to form precipitates with the alkali and the indicator, which interferes with the judgment of the end point. The use of methyl orange, which changes color earlier, as an indicator will also produce serious systematic errors
If the titration is carried out directly with sodium hydroxide standard solution on the potentiometric titration, the titration result shows multiple equivalence points, and each equivalence point has a small jump, and it is necessary to manually analyze and judge the equivalence point of free acid, which is easy to produce Ambiguity and errors

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] The concentration of free acid in the electroplating solution calculated by pre-calibration contains about 12mol / L of hydrochloric acid.

[0027] Prepare 0.1mol / L NaOH standard solution, use potassium hydrogen phthalate standard reagent to calibrate, the concentration that obtains this NaOH standard titration solution is C (NaOH) = 0.1042 mol / L.

[0028] Weigh about 3.72g of EDTA-Na into a 500mL beaker, add about 300mL of water, heat at low temperature, cool to room temperature after all dissolve, and dilute to 1000mL to obtain an EDTA solution with a concentration of 0.01mol / L.

[0029] Dispense 10.00mL of electroplating solution into a 100mL volumetric flask and dilute with water to the mark. Then take 10.00mL of the diluted electroplating solution in a 100mL volumetric flask, and dilute with water to the mark again. Take two 10.00mL portions of the re-diluted solution and put them into 100mL beakers respectively. Separately, add 5 mL of EDTA solution with a concen...

Embodiment 2

[0031] The concentration of free sulfuric acid in the copper electrolyte calculated by pre-calibration is about 2mol / L.

[0032] Prepare 0.1mol / L NaOH standard solution, use potassium hydrogen phthalate standard reagent to calibrate, the concentration that obtains this NaOH standard titration solution is C (NaOH) = 0.1242 mol / L.

[0033] Weigh about 18.61g of EDTA-Na into a 100mL beaker, add about 40mL of water, heat at low temperature, cool to room temperature after all dissolve, and dilute to 100mL to obtain an EDTA solution with a concentration of 0.5mol / L.

[0034] Dispense 5.00mL of electroplating solution into a 100mL volumetric flask and dilute with water to the mark. Take two 10.00mL portions of the diluted solution and put them into 100mL beakers respectively. Separately, add 15 mL of 0.5 mol / L EDTA solution and 30 mL of distilled water into two 100 mL beakers, put in a stirring magnet, and immerse the electrodes in the solution. Use 0.1242mol / L NaOH standard titra...

Embodiment 3

[0036] The concentration of free acid in the car plate pickling solution calculated by pre-calibration is about 0.1mol / L.

[0037] Prepare 0.1mol / L NaOH standard solution, use potassium hydrogen phthalate standard reagent to calibrate, the concentration that obtains this NaOH standard titration solution is C (NaOH) =0.1149 mol / L.

[0038] Weigh about 3.72g of EDTA-Na into a 500mL beaker, add about 300mL of water, heat at low temperature, cool to room temperature after all dissolved, and dilute to 1000mL to obtain an EDTA solution with a concentration of about 0.01mol / L.

[0039] Take two parts of 2.00mL electroplating solution and place them in 100mL beakers respectively. Add 1mL0.01mol / LEDTA solution and 60mL distilled water to the two 100mL beakers respectively, put in a stirring magnet, and immerse the electrodes in the solution. Use 0.1149mol / L NaOH standard titration solution to perform potentiometric titration automatically. It can be seen from the titration chart that ...

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PUM

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Abstract

The invention provides a fast and accurate method for measuring free acid concentration in acid liquid. An automatic potentiometric titrator is used to measure total acidity of the acid liquid. EDTA (ethylene diamine tetraacetic acid) which prevents iron ions, aluminum ions and the like from hydrolyzing is used as a screening agent to eliminate influence of hydrolysis of the iron ions, the aluminum ions and the like to free acid measurement. The defect that pH jump of the free acid is fully or partially covered during automatic potentionmetric titration is avoided. Jump of equivalent point is increased, and accuracy of the measurement is increased. An analysis result is automatically calculated according to an input formula. Operation time from analysis to result obtaining is shortened to less than 10 minutes. In addition, the method is low in sampling amount, fine in reproducibility, and accurate in analysis results. By the method, labor intensity of analysts is reduced, and labor productivity is emancipated.

Description

technical field [0001] The invention relates to a method for free acid concentration in acid solution. Background technique [0002] During the production process of cold-rolled sheet, the surface of the continuous casting slab should be pickled with acid solution to remove the iron oxide scale on the surface. The free acid concentration of the acid solution will have a certain impact on the surface treatment quality, so the rapid and accurate determination of the total free acid concentration in the acid solution has a great guiding role in the research and improvement of the pickling effect and pickling process. [0003] At present, acid-base manual titration or potentiometric titration is mostly used to determine the free concentration in acid solution. Manual titration is cumbersome and time-consuming. During the titration, as the pH rises during the titration process, the iron ions in the acid solution tend to form precipitates with the alkali and the indicator, which...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N27/42
Inventor 闻向东邵梅张穗忠周郑吴秀云朱缨夏念平赵希文文斌
Owner 武钢集团有限公司
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