This article is a critical review of recent research
pursued in India on mechanical activation of bauxite and industrial
wastes, namely blast furnace slag and fly ash. The emphasis is on
unique findings in terms of basic understanding and process
innovations. Importance of pure minerals and their mixtures is
brought to focus to unravel the intricacies involved during the
activation of multi-mineralic ore such as bauxite. In the gibbsitehematite
mixture, hematite which is a hard mineral, can enhance
the activation of gibbsite. Use of mechanical activation as a pretreatment,
or simultaneously during alkali leaching of bauxite,
results in moderation in leaching condition and significant
reduction in soda and alumina losses in the red mud, and thus,
paving the way for a newer technology. Judicious selection of
milling device is the key to achieve hydration of blast furnace slag
without any chemical activation. Quite interestingly, complete
hydration of the slag which takes several years is possible in about
a month time for an attrition milled slag. The hydration product of
slag shows unique features in terms of crystallinity and phases
present. Portland slag cements containing upto 80-85% slag can be
produced using the activated slag. The results on fly ash revolve
around mechanically induced and glass content induced reactivity