Abstract：After the organic carbon and carbonate were eliminated by low temperature combustion (which was lower than 500 ℃)and addition of phosphoric acid to no bubble, the sample was placed and heated at low temperature in airtight experimental equipment system which was prefilled with oxygen. While, the fixed carbon(graphite carbon) in the sample was oxidized with potassium dichromate to generate carbon dioxide gas in a short time with sulfuric acid as reaction medium and silver sulfate as catalyst. After removal of hydrogen fluoride, hydrogen sulfide and moisture, the released gas was absorbed by the absorbent composed of potassium hydroxide, ethanol and ethanolamine (which was pre-adjusted to blue by ethanol-ethanolamine titration solution) and titrated by ethanol-ethanolamine titration solution with thymolphthalein as indicator. As for the titration end point, the blue color of absorbent should be kept for 1 min. On the basis of this, a determination method of fixed carbon with mass fraction less than 30% in graphite ore by nonaqueous titration was established. The proposed method was applied to the determination of fixed carbon in certified reference materials of graphite ore. The results were basically consistent with the certified values. The relative standard deviation (RSD, n=10) were between 1.1% and 3.1%. The fixed carbon in graphite ore actual sample was determined according to the experimental method, and the results were basically consistent with those obtained by gravimetric method and high temperature ignition-nonaqueous titration method. The recoveries of method were between 98% and 103%.
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