Cement manufacturing consumes large quantities of nonrenewable raw materials (minerals and fossil fuels). It is also an important source of CO2 emissions.
In response to this environmental challenge, Lafarge has been committed to the path of industrial ecology since the mid-70s. This approach is inspired by the cycles of creation, destruction and recycling that occur in nature. By rethinking industrial processes from start to finish, one industry's waste products can become another industry's resources.
Why find uses for waste? |
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The Group is aware of the impact of its activities on the environment. As a result, Lafarge started thinking at a very early stage about ways of reconciling industrial imperatives with the preservation of ecosystems. Adding value to waste by using it as alternative fuel or materials, makes it possible to:
In 2007, Lafarge recycled over 7.7 million tons of biomass, waste and by-products from industry and agriculture. This reduced the amount of CO2 released into the atmosphere by more than 10 million tons. The benefit for the planet was equivalent to planting more than 660 million trees!
Industrial ecology practices are, therefore, beneficial for the community and the environment and also have economical benefits for Lafarge. |
CO2 and cementWhy does the manufacture of cement produce CO2? Cement manufacturing is the source of 5% of global CO2 emissions. The cement industry is a natural producer of CO2:
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Alternative fuels |
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Kyoto ProtocolThe Kyoto Protocol aims to counter climate change by reducing carbon dioxide emissions. In effect since February 2005, it has been ratified by over 150 countries but has not been ratified by the United States for example. Under the Protocol, industrialized countries have until 2012 to reduce their CO2 emissions by 5.2% compared to 1990 levels. |
Waste products can be a very appealing alternative to fossil fuels. In general, alternative fuels are derived from waste or byproducts from agriculture (biomass) and industry:
All of these products can be recycled as alternative fuels and burned safely in cement kilns. This approach relieves the community of the need to process this waste and helps to limit CO2 emissions. The extremely high temperatures found in cement kilns mean that the waste is totally eliminated and does not leave any residue. At present, alternative fuels account for 10.7% of the Group's fuel use across all Businesses.
Lafarge actively participates in the Clean Development Mechanisms (C.D.M.) system initiated under the Kyoto Protocol. These mechanisms encourage the implementation of best-in-class technologies in developing countries by providing carbon credits to companies which finance sustainable development projects. For example, in:
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Alternative materials |
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The cement manufacturing process generates CO2 because the limestone needs to be heated to very high temperatures. This physical-chemical process of "decarbonation" produces clinker, which is then ground down. It is possible to reduce the amount of clinker in cement by using alternatives, called cement admixtures. Reducing the amount of clinker in cement offers 2 advantages:
Cement admixtures may be of:
For example, in India, the Arasmeta cement plant uses fly ash from power plants in cement manufacture.
The Group takes a pro-active approach to alternatives: the ratio of alternative materials used in 2007 to produce cement to total cement produced increased to 16.5% (15% in both 2006 and 2005). |
Clinker
Clinker is the main ingredient in cement. These hardened granules are obtained by firing a mixture of approximately 80% limestone and 20% clay to a high temperature. Cement is obtained by grinding clinker and, in some cases, supplementing it with additives.
PozzolanPozzolan is named after Pozzouli, a region near Naples, Italy, which is rich in volcanic ash. Natural pozzolan is a light siliceous mineral produced during basaltic volcanic eruptions. It contains silica, alumina and iron oxide (which gives it a red color), as well as lime and magnesium oxide. Pozzolan is used as a cement additive. Artificial pozzolans with the same properties as natural pozzolans can be created by heating clays, basalts or schists. Fly ashFly ash is hydrophilic and can be used as a cementitious additive. The ash, which is collected from chimney filters in coal-fired power plants, is composed of vitreous silica, alumina, iron oxide and lime. They can be used as a partial substitute for clinker and thus help to reduce CO2 emissions. |
Lafarge expertise results in safe waste solutions |
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The use of waste products cannot be improvised. Lafarge has implemented stringent quality control standards as well as a training policy for its engineers, technicians and foremen. In this way, it is reinforcing the use of alternative fuels and materials while controlling industrial processes. The Group's R&D teams are also making an active contribution in this respect.
The Cement Business considers the use of alternatives and the pursuit of industrial ecology to be separate but complementary parts of its core business. The Business has developed a highly professional strategy as well as expertise and a dedicated organization at Group level and within operational units. The Group also establishes partnerships with local waste processing specialists. Lafarge has acquired share capital in Systech, a major waste management company in North America. |
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Last update on 10/06/2008
