GB/T 23941-2025 in English

Standard Revision Background and Technological Evolution

GB/T 23941-2025, the latest national standard for the analysis of industrial calcium chloride, replaces the 2009 version, which had been in effect for 16 years. This revision primarily addresses three technical needs: expansion of test parameters (adding four new parameters, including total magnesium and total alkali metal chloride), method optimization (adding visual turbidimetry to sulfate determination), and adaptation to industrial applications (improving the solid/solution dual-state detection system).

Comparison of Core Detection Methods

Details of key detection technologies

4.3 Determination of calcium chloride content

EDTA complexometric titration was used at pH 12 with calcium reagent sodium carboxylate as indicator. Technical points:

• Sample processing: 8-10g solid sample needs to be accurate to 0.0002g
• End point determination: The sudden change of the solution from red to blue
• Calculation formula: Introduce a correction factor of 1.498 calcium hydroxide

4.7 Comparison of two methods for sulfate

Standard implementation recommendations

1. The laboratory must be equipped with a pH meter (0.01 resolution) and a spectrophotometer (4cm cuvette)
2. When testing for total alkali chloride, pay attention to controlling the pH between 6.5 and 10.0
3. The test methods for magnesium and alkali metal salts have been deleted in the new version. It is recommended to use the newly added methods in sections 4.5/4.9 instead.

Safety Warning

The standard specifically emphasizes that potassium chromate indicator is toxic and hydrochloric acid solution is corrosive. Protective equipment should be worn during operation, and the experimental area must be equipped with an emergency flushing device.