The company will install this newly-developed process at its Lakheri unit in Rajasthan soon, and has moved the Patents Controller of India for patenting the new process. The company also hopes to globally patent the cement-making process in due course.

Reactive belite cement--as the new cement variety is called--can be developed at a lower temperature and can take in inferior grades of limestone. The cement will be available in all existing varieties including 53-grade, 43-grade and composite cement.

"The energy saving will be to the tune of 150 degrees celsius, and the limestone quality may be much inferior to what is being currently used," a top ACC official told The Financial Express.

The companyhas finetuned the new process at its R&D centre at Thane, and hopes to start commercial production in a short while.

"The new process will be tried at the Lakheri unit and subsequently will be extended to two other manufacturing facilities where there are large stocks of inferior-grade limestone," ACC sources said.

Conventional cement, they added, contains two crucial chemical compounds-alite and belite-which contributes to its strength and durability. However, alite has got inherent limitations as it becomes reactive only at a very high temperature (1400 degrees celsius) and with a relatively superior-quality limestone. Belite, on the contrary, is a slow-reacting chemical compound.

"Therefore, we decided to do away with alite, and instead make the other compound belite more reactive so that it performs the functions of alite as well," he said.

"Without changing the basic chemistry we changed the firing and cooling schedule making belite, which is a relatively inert chemical compound, more reactive,"he added.

A new design pilot clinker cooler has been set up which can produce reactive belite cement, which is as good, if not better than conventional cement," ACC officials said.

Limestone deposits in the country are generally of inferior grade. The problem becomes all the more acute for cement companies as the relatively better-quality limestone deposits are reserved for the steel sector. Cement companies, for which limestone is a crucial raw material, often have to set up beneficiation processes to improve its quality, and this in effect hikes the cost of manufacturing.

The problem for cement companies gets compounded by the fact that the ash-content in coal is also very high. Most cement producers thus have to procure chemical-grade limestone to add to the local variety so as to make it usable.

"The exact amount of savings that the new process will result in is difficult to say at this juncture. All we can say now is that the manufacturing costs will drop significantly as a result," the ACCofficials said.

INSIGHT

Limestone cost can by itself cause a huge difference in the cost of cement. This can be seen higher cost of raw materials for Madras Cement, and ACC compared to that of Gujarat Ambuja and other companies in Gujarat and AP, who have an access to softer and better raw materials. Hence, the process innovation is quite important as that would reduce the processing cost which is in the control of the company, in contrast to raw materials -- the condition of which is totally outside the ambit of any management or engineering. Since bulk of the cement capacities are outside Gujarat and AP, the company can also earn suitable royalty payments from various other cement facilities across the country.

--Manish Saxena