USE OF HIGH PHOSPHATE LIMESTONE IN CEMENT MANUFACTURE – A CASE STUDY

Over the past two decades The Associated Cement Companies Ltd (ACC) India, has been involved in a number of assignments of raw mix optimisation for productivity enhancement  and for Quality up-gradation, for its own cement plants and for clients  in India and abroad . The salient features of some of the case studies have been published at National and International forums.  The case study discussed in this paper discusses the investigation on one of such assignments where  the cement quality trends indicated unusually high setting time and poor development of compressive strengths.

Raw Material in process and cement characterisation revealed presence of phosphate minerals in raw materials and its derivatives in processed material as responsible for the quality related problems. The paper discusses  the laboratory studies and raw mix  designs carried out for modifying the clinker properties to overcome the slow setting and poor compressive strengths in cements.