SN/T 4761-2017 in English

Standard Overview

This standard specifies the method for determining the fluorine content in coal using the high-temperature hydrolysis-automatic potentiometric titrator, and is applicable to the analysis of coal samples with a fluorine content ranging from 50μg/g to 1500μg/g.

Technical Principle

Instrument configuration requirements

Method Innovation

Compared with the traditional distillation method, this standard:

1. Shortened the analysis time from 4 hours to 40 minutes
2. Adopted gradient temperature control technology to avoid fluoride volatilization loss
3. Introduced automatic endpoint determination system to reduce human error

Implementation Suggestions

Key points of quality control:

• The particle size of coal samples should be controlled between 0.2-0.5mm
• The blank value and standard substance should be measured simultaneously for each batch
• The lanthanum standard solution should be stored at 4℃ in the dark and the shelf life should be ≤1 week

Abnormal handling: When the recovery rate exceeds the range of 90%-110%, the quartz tube sealing and carrier gas purity (≥99.99%) should be checked.