GB/T 38216.2-2019Steel slag—Determination of fluoride content and chloride content—Ion chromatography (English PDF)

1 Scope

This Part of GB/T 38216 specifies the method to determine the content of fluorine and chlorine in steel slag by ion chromatography.

This Part is applicable to the determination of fluorine and chlorine content in steel slag. Determination range (mass fraction): 0.05%~2.0% for fluorine, 0.005%~0.1% for chlorine.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

GB/T 2007.2, General rules for the sampling and sample preparation of minerals in bulk-Manual method of sample preparation

GB/T 6682, Water for analytical laboratory use - Specification and test methods

GB/T 8170, Rules of rounding off for numerical values & expression and judgement of limiting values

GB/T 12806, Laboratory glassware - One-mark volumetric flasks

GB/T 12807, Laboratory glassware - Graduated pipettes

GB/T 12808, Laboratory glassware - One-mark pipettes

GB/T 36240-2018, Ion chromatographs

3 Principle

The specimen is decomposed by sulfuric acid. Fluorine and chlorine escape with water vapor and separate from the sample. It is absorbed by absorption liquid. Use ion chromatography to determine. Qualitatively determine fluorine and chlorine by the peak time. Use the standard curve to quantitatively determine.

4 Reagents and materials

Unless otherwise specified, the reagents used are guaranteed reagents, and the experimental water is grade one water specified in GB/T 6682.

4.1 Sodium hydroxide.

4.2 Sodium fluoride, the reference substance.

4.3 Sodium chloride, the reference substance.

4.4 Concentrated sulfuric acid, rho=1.84g/mL.

4.5 Sulfuric acid solution (2+1): Measure 200mL of concentrated sulfuric acid (see 4.4) and slowly pour into 100mL of water. Mix well.

4.8 Chlorine standard stock solution: Accurately weigh 1.6485g of reference sodium chloride that has been burned to constant weight at 500°C~600°C (see 4.3). Dissolve in water. Transfer to a 1000mL volumetric flask. Use water to dilute to the scale mark. Shake well. 1mL of this solution contains 1000µg of chlorine.

4.9 Fluorine and chlorine mixed standard solution: Accurately pipette 5.00mL of fluorine standard storage solution and chlorine standard storage solution respectively (see 4.7 and 4.8) into a 50mL volumetric flask. Use water to dilute to the scale mark. 1mL of this solution contains 100.0µg of fluorine or chlorine respectively.

5 Instruments and equipment

5.8 Glassware: All glassware must be soaked in 2mol/L sodium hydroxide solution and water for 4h before use. Then use water to rinse 3~5 times. Let dry and set aside.

5.9 The volumetric flask shall meet the requirements of GB/T 12806. The pipette shall meet the requirements of GB/T 12807 and GB/T 12808.

6 Sample preparation

Prepare the specimen according to the method in GB/T 2007.2. The particle size of the specimen is not greater than 0.080mm. Place the sieved specimen in an oven (see 5.1) at 105°C±2°C for 1h. Take it out. Place it in a desiccator to cool to room temperature for future use.

7 Test steps