Method for detecting chloride ion impurities in high concentration chromic anhydride solution

Abstract

The invention discloses a method for detecting chloride ion impurities in a high concentration chromic anhydride solution, which comprises the following steps of dispensing the high concentration chromic anhydride solution to be detected to be placed in a titration glass, dropwise adding an alkaline adjusting solution into the chromic anhydride solution under the uniform stirring of an automatic potentiometric titrator, adjusting potential of hydrogen (pH) value of the solution to be detected to 4.5 to 5, then setting the maximum jumping point detected by the automatic potentiometric titrator as a titration end point, starting the automatic potentiometric titrator, titrating by a silver nitrate standard solution, performing blank titration of corresponding reagents, and calculating content of chloride ions according to a standard formula. The alkaline solution is a 25% sodium hydroxide solution, and the concentration of the silver nitrate standard solution is 0.0400mol/L. The method for detecting chloride ion impurities in the high concentration chromic anhydride solution has the advantages that the conventional automatic potentiometric titrator is used, adjustment is performed by addition of the sodium hydroxide solution, extreme influences of solution color on the detection are eliminated, quantitative detection of the chloride ion impurities in the high concentration chromic anhydride solution which is repeatedly used is achieved, and the rapid detection requirement in the industrial production process is met.

Description

technical field [0001] The invention relates to the detection of chloride ion content in a high-concentration chromic anhydride solution (≥40g / L), in particular to a detection method for chloride ion impurities in a high-concentration chromic anhydride solution repeatedly used in a surface treatment process. Background technique [0002] The high-concentration chromic anhydride (≥40g / L) solution used in the surface treatment of parts in the manufacturing industry will gradually bring in impurities during repeated use in production, forming a variety of ions (sulfate ions, calcium ions, chloride ions, etc. ) mixed solution. Since the chromic anhydride solution not only requires the chromic anhydride component to be within the specified reasonable range, but also has strict requirements on the content of harmful impurities chloride ions, it is necessary to detect the content of chloride ions in the mixed solution to ensure that the chromic anhydride used in production The chl...

AI Technical Summary

Problems solved by technology

However, the high-concentration chromic anhydride solution used repeatedly has turned into a dark brown solution due to the high content of impurities. The conventional detection method cannot accurately detect the harmful impurity chloride ions, which cannot meet the requirements of industrial production. RAPID TEST REQUIREMENTS

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