Reverse-phase extraction and separation of minerals in cement clinker and the sulfur fixation mechanism for CaO, Al2O3, Fe2O3 and CaSO4 particles

摘要

The emission of SO2 during cement production will lead to environmental pollution, but cement clinker has a certain effect on sulfur fixation. To study the mechanism of sulfur fixation of cement clinker, we have separated the sulfur-containing minerals in cement clinkers by the three-step method of reverse-phase extraction, separation and enrichment. In addition, we have analyzed the mineral phases of varying temperature segments by using the technique of X-ray diffraction and explored the changes of SO2 during reaction by adopting the method of simultaneous thermal analysis-Fourier transform infrared spectrometer. We have identified two sulfur-fixing systems present in raw cement through testing, namely, the sulfur-fixing system of CaO-Al2O3-CaSO4 aluminum phase, and the sulfur-fixing system of CaO-Al2O3-Fe2O3-CaSO4 iron aluminate phase. The former system plays a major role in sulfur fixation at the range of 1150-1400 degrees C, whereas the latter plays a key role at the range of 1400-1450 degrees C.