Study on the correlation between Fe/Ti forms and reaction activity high-alumina coal fly ash

High-alumina coal fly ash (HAFA) is an important aluminum and silicon resource. In the process of preparing aluminum-silicon materials from HAFA, the influence of impurity elements on its performance must be considered. In this work, the occurrence state of impurities in HAFA, micro morphology, and the bond energy of different impurity coordination were studied. Sulfuric add leaching method and density functional theory were used to study the leaching behavior of impurities to verify the difficulty of removing different impurity elements. The results show that iron existed in the form of magnetic particles (34.78%), amorphous phase (49.24%), and crystalline phase (15.96%) in HAFA. Titanium mainly existed in amorphous phase (29.34%) and crystalline phase (69.4%). In sulfuric add leaching, titanium was more difficult to leach, and the content of TiO2 decreased from 2.30% to 225%, whereas that of Fe2O3 decreased from 1.50% to 0.86%. The actual leaching behavior of impurity elements was consistent with the simulation results, with more energy required to remove Ti than Fe. These studies of impurity elements in HAFA will provide theoretical support for the preparation of aluminum-silicon materials. (C) 2021 Elsevier B.V. An rights reserved.

Automated summary

This study investigated the impurity elements in high-alumina coal fly ash (HAFA) and found the occurrence form and leaching behavior of iron and titanium, further confirming the difficulty of removing different impurity elements. The results provide theoretical support for the preparation of aluminum-silicon materials.