XRFS Determination of Chloride in Raw Coal

XRFS determination of chloride in raw coal with sample preparation of disc sample by direct pressing of coal powder was proposed in this paper. The raw coal was powdered to the size less than 74 μm, dried at 90 ℃ and pressed in a polyethylene mould under a pressure of 4.16 MPa to form a disc sample with its diameter of  35 mm. The sample disc should be kept in desiccator and used for determination as soon as possible. Working curve was prepared with a set of CRM′s covering the range of chloride contents from (w) 0.01% to 0.11%. A 3 in 1 regression equation functioning as working curve, matrix correction and spectral overlapping correction was established and used as basis of quantification. Detection limit of the method was found to be 15 μg·g-1. Value of RSD (n=12) of 1.85% was found by repetitive determinations of a CRM having the certified value of Cl of (w) 0.057%. The proposed method was used in analyzing 2 CRM′s, giving values of Cl contents in consistency with the certified values.