Investigation on ash fusion characteristics during the co-gasification of coal and textile dyeing sludge

• Published in: Journal of thermal analysis and calorimetry 2023-12, Vol.148 (24), p.14011-14022
• Main Authors: Zhao, Chaoyue, Bai, Yonghui, Li, Fenghai, Yu, Guangsuo, Yao, Min
• Format: Article
• Language: English
• Subjects: Aluminosilicates; Analytical Chemistry; Anorthite; Anthracite; Ashes; Bonding strength; Bonds; Calcium aluminum silicates; Calcium ions; Chemistry; Chemistry and Materials Science; Coal; Coal gasification; Depolymerization; Eutectic temperature; Ferrous ions; Fourier transforms; Hercynite; Infrared spectroscopy; Inorganic Chemistry; Investigations; Liquid phases; Low temperature; Mathematical analysis; Measurement Science and Instrumentation; Melting; Oxygen; Physical Chemistry; Plagioclase; Polymer Sciences; Raman spectroscopy; Silicates; Silicon; Sludge; Spectrum analysis; Spinel group
• ISSN: 1388-6150; 1588-2926
• DOI: 10.1007/s10973-023-12687-z

The co-gasification of coal and textile dyeing sludge (TDS) is an effective way to handle the huge production volumes of TDS and its associated problems. In this study, the influence of TDS on the fusion behavior of Yongcheng anthracite coal (YC) was investigated using an ash fusion temperatures (AFTs) analyzer under a reducing atmosphere. The regulating mechanisms of mineral transformations, aggregation degree of the aluminosilicate network, and liquid phase content were investigated by X-ray diffractometery, Fourier transform infrared spectroscopy and Raman spectroscopy. Slag and network theory calculations and FactSage thermodynamic software calculations were also performed. The results showed that the AFTs of YC decreased upon increasing the TDS mass ratio, and the flow temperature decreased to 1643.15 K when the TDS content reached 20%. The formation of feldspar minerals (anorthite, albite, hercynite, etc.) and the low-temperature eutectic were the main reasons for the decrease in the AFTs. The bridging oxygen bonds of the mixed ashes network were destroyed by metal ions (i.e., Fe 2+ , Ca 2+ , Na + ) from the TDS. The presence of non-bridging oxygen bonds was confirmed, and the peak strengths of Si–O-Si and Si–O-Al bonds decreased. The intensity of Si–O-M(M: Ca 2+ , Fe 2+ , or Na + ) vibrational gradually increased. The proportion of four configurations of Si–O bonds also increased upon increasing the TDS content, which promoted the depolymerization of the silicate melt and decreased the AFTs. FactSage calculations were in good agreement with the experimental ash fusion behavior. Graphical abstract