ABSTRACT
The world consumption of portland cement has risen from less than two million tons in 1880 to more than one billion tons in 1996. Besides other raw materials, the production of each ton of portland cement requires approximately 1.5 tons of limestone, and considerable amounts of both fossil fuel and electrical energy. Also, it is well known that the production of each ton of portland-cement clinker is accompanied by the release of approximately one ton of carbon dioxide, which is one of the gases primarily responsible for the greenhouse effect and global warming. The portland cement industry, considered as one of the energy-intensive and environment-polluting industries, is likely to come under increasing scrutiny in the industrially developed countries which have for the first time accepted legallybinding commitments to reduce the emission of gases contributing to global warming in accordance with the recently (December, 1997) concluded Kyoto Protocol to the UN Framework Convention on Climate Change.
