Cl and Br content
Sample placement: 16h, temperature (21～25)℃, humidity (45～55)%. Two samples, each (500-1000) mg, were crushed to 0.1 mg.
The air flow is (0.0157·D2)l·h-1±10%, and the sample is heated uniformly for 40min to (800±10)℃, and kept for 20min.
The gas generated by the test sample is sucked through a gas washing bottle containing 220ml/piece of 0.1M sodium hydroxide solution; the liquids of the two gas washing bottles are injected into the measuring bottle, and the gas washing bottle and its accessories should be washed with distilled water at the same time and added to the measuring bottle. 1000ml, after cooling to room temperature, drop 200ml of the tested solution into the measuring bottle with a pipette, add 4ml of concentrated nitric acid, 20ml of 0.1M silver nitrate, 3ml of nitrobenzene, then stir until white flocs are deposited; add 40% ammonium sulfate The aqueous solution and a few drops of nitric acid solution were mixed thoroughly, stirred with a magnetic stirrer, and ammonium sulphate was added to titrate the solution.
Requirements: the mean of the test values ​​of the two samples: HCL≤0.5%; HBr≤0.5%;
The test value of each sample is less than or equal to the mean ±10% of the test value of two samples.
F content
Put 25-30 mg of sample material into a 1-L oxygen container, drop 2-3 drops of alkanol, and add 5 ml of 0.5M sodium hydroxide solution. The swatches were allowed to burn out and the residue was poured into a 50ml measuring cup by light rinsing.
Mix 5 ml of buffer in the sample solution and wash solution and reach the mark. Draw the calibration curve, get the fluorine concentration of the sample solution, and obtain the percent fluorine content in the sample by calculation.
Requirements: ≤0.1%.