Abstract:
A method was proposed for determination of the halogens in coal using high temperature pyrolysis pretreatment and ion chromatography. The coal sample (30.0-40.0 mg) was treated by pyrolysis at 1 100 ℃ in the oxygen of 350 mL·min
-1, and then the gas products of pyrolysis were absorbed in 5mL of 20 mmol·L
-1 NaOH solution. F
-, Cl
- and Br
- in the absorption solution were determined by ion chromatography with suppressed conductivity detector and IonPac AS18 column, and I
- in the absorption solution was determined by ion chromatography with integrated amperometric detector and Ionpac AS11-HC column. As shown by the results, linear relationships between values of peak area and mass concentration of F
-, Cl
-, Br
- and I
- were found in definite ranges, with detection limts (3
s) of 3.03 mg·kg
-1 for F
-, 2.47 mg·kg
-1 for Cl
-, 0.80 mg·kg
-1 for Br
- and 8.85 mg·kg
-1 for I
-. Values of RSD (
n=9) for precision test were all less than 5.0%. Test for recovery was made by standard addition method for the coal sample, giving results in the range of 83.6%-105%.