Effect of anhydrite on hydration properties of mechanically activated muscovite in the presence of calcium oxide

摘要

The study of the hydration properties of mechanically activated muscovite (a common mineral phase in mine tailings) was a new subject. In this paper, the effect of natural anhydrite on the hydration properties of calcium oxide-activated muscovite after mechanical activation was investigated. The mechanically activated muscovite was activated by two types of activators: calcium oxide and calcium oxide blended with natural anhydrite with contents ranging from 5%, 10%, and 15%. The hydration properties were analyzed by X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) techniques. It was found that mechanical activation was beneficial for improving the reactivity of muscovite, and the addition of calcium oxide in the mechanically activated muscovite promoted the formation of stratlingite, hydrotalcite, and C-A-S-H gel; the addition of natural anhydrite inhibited the formation of the above hydration products but promoted the formation of ettringite. The increase of anhydrite content was beneficial to the formation of ettringite. It was concluded that the muscovite possessed pozzolanic activity after mechanical activation, and it could react with calcium oxide and natural anhydrite to form hydration products.