The determination of ignition residue content:

Ignition residue content index in the national standard GB 7744-7744 "industrial hydrofluoric acid" is not in control, Japan standard JIS K1405-1995 the hydrofluoric acid for the rules of this index, index parameter is not greater than 0.05%. Due to the changes mainly refer to the provisions of the standard in Japan, therefore this standard on the product quality requirements are relatively high Ⅰ products through three specifications, with specific parameters is not greater than 0.05%, the same with the Japanese standards.

Collected from domestic and foreign relevant product standards, the standard on the measurement method of the same project, such as hydrofluoric acid content using phenolphthalein as indicator, with sodium hydroxide standard titration solution as titrant acid-base neutralization titration method; Determination of use in the presence of potassium fluosilicate content makes it generate fluorosilicate after separation, precipitation titration with sodium hydroxide standard titration solution after dissolving. For the determination of low content of fluosilicate, generally USES the silicon molybdenum blue spectrophotometric method for determination of; Sulfate content determination is separate the hydrofluoric acid, the titration with sodium hydroxide standard solution titration. Japanese standards specified in the ignition residue content determination of 700 ℃ under stable after calcination method.

Japanese standard (include anhydrous hydrofluoric acid) on the determination of fluorine content of silicic acid provides for two methods, the Japanese standard for aquatic products of high fluorine content of silicic acid (containing less than 0.05%) using acid-base titration, for no aquatic fluorosilicic acid content (less than 0.01%) silicon molybdenum blue spectrophotometric method. The standard measurement Ⅰ products fluorosilicic acid content (less than 0.05%) of silicon molybdenum blue spectrophotometric determination of fluorine content of silicic acid, type Ⅱ product (content greater than 2.5%) using acid-base titration.