Study on hydrothermal properties of MgO-rich and Low-alkalinity steel slag

摘要

This paper describes the process of Mg-rich and low-alkalinity steel slag. changing into tobermorite-like minerals. It's shown that, CMS begins to react with water at 220 degree under hydrothermal condition, and both xonotlite and chrysolite are the final phases at 270 degree. C_3MS_2 is reacted wholly when autoclaved at 200 degree, forming Mg-rich calcium silicate hydrates. However, Mg-rich and low-alkalinity steel slag reacts a little at 150 degree, converts into tobermorite-like mineral entirely at 300 degree, and has better cementitiousness. It is suggested that Mg~(2+) ions are first incorporated to the structure lattices of calcium silicate hydrates, then according to reaction temperature, the excess Mg~(2+) ions could form Mg(OH)_2 or chrysolite.