Cement, Energy and Environment

Converting Adversities into Opportunities: Introducing Low Energy Cements for Making Cement Manufacturing Truly Sustainable DrS PPandey Dalmia Cement (Bharat) Ltd Introduction: Owing to an increased impetus on infrastructure development in the country over the past few years, demand for cement and concrete is increasing significantly. Cement and concrete applications, being backbone of modern construction & infrastructure, are thus expected to be the growth engines for accelerating the pace of developmental activities further in the years to come. At the same time, the Cement and Building Material Industry in the country is also anticipating a radical change in current cement manufacturing and concrete application practices in order to address issues pertaining to consolidation within the industry due to increasing interests of global cement players, customer expectations, environmental concerns & regulatory pressures, energy as well as raw materials conservation, etc. As a result, the cement and concrete products are experiencing evolution from bulk commodities to tailor made applications with variety of differentiated value added products meeting specific needs of customers. With these changes happening, it is imperative for the group to focus on sustainable future growth backed by a strong research and innovation which can help the management in effecting the transition as smoothly as possible. Today's processing industries, including cement manufacturing, are finding themselves in situations wherein they are forced to tackle problems related to depletion of favorable raw material resources, more stringent environmental regulations, higher overhead costs and shrinking profit margins. The major raw material problems in cement manufacturing which have already started hampering many of our manufacturing operations include increasing presence of minor constituents like alkali, sulfur, magnesia, iron or silica in limestone deposits with progressively increasing mines age and vast quantities of marginal grade limestone deposits having sub-optimal lime content (CaO < 42-43%) when assessed in the light of current raw material specifications. Present practice of meeting quality specifications of conventional Ordinary Portland cement clinker, by maintaining desired cutoffs in the raw material quality, has thus resulted in accumulation of huge limestone reserves which are currently unusable. Availability of around 20 million tonnes of limestone having total carbonates (TC) below 73% at VCW, around 7.5million tonnes having TC < 73- 74% each at GCW and GS, around 3.5 million tonnes having TC < 75% and around 200 million tonnes having TC in the range of 70-75% at RC are some of the demonstrative cases indicating abundance of non-favourable limestone reserves. Similarly limestone deposits having LSF > 70% but having undesirable sulfate levels more than 0.8% are available in the range of around 140 million tonnes at ACW. Unless and until this resource productivity related issues are dealt with proactively, maintaining groups' leadership in cement manufacturing is expected to be a challeng ing task. Other major concern while maintaining cement sustainability is to initiate steps in altering image of cement producers as major emitters of green house gases (primarily C0 2 ). Cement production inherently consumes large amounts of materials and energy both of which are carbon intensive. It is attributed to combustion requirements for limestone calcination and the calcination reaction itself, which produces huge amount of carbon dioxide. The carbon dioxide in the flue gas from cement production normally ranges from 22 to 28% on a molar basis. According to certain estimates, cement industry is responsible for approximately 4-5% of the global carbon dioxide emissions. Based on worldwide cement production and associated C0 2 emissions, the average gross unit-based em1ss1ons for the industry is approximately 700 kg C0 2 per ton of cementitious material as compared to our group average of about 655. A more pragmatic and path breaking