Science & Technology in Action

6th Edition

Science, Technology and Responsibility

CRH

There is widespread concern about the long-term sustainability of industrial activities that affect the environment. This lesson describes how a major global building materials company fulfils its corporate social responsibility as it works to reduce or ameliorate the environmental impact of its operations.
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Contains the full lesson along with a supporting toolkit, including teachers’ notes.

Lesson excerpt

Industry and the Environment
Currently there is widespread concern about the long-term sustainability of industrial activities that affect the environment. The science and technology we use to produce the goods and services we need can impact soil, water and air. In this lesson we look at how CRH, the major global building materials company, fulfils itscorporate social responsibility as it works to reduce or ameliorate the environmental impact of its business operations.

Cement – The Essential Building Material
Cement is produced by burninglimestone (calcium carbonate, CaCO3), together with other raw materials, mainlyshale, in a kiln. Modern cement kilns operate at temperatures up to 1450°C which are necessary to produce the kiln output calledclinker. The clinkeris then mixed with small amounts of gypsum and ground to the fine powder that we recognise as cement.

Emissions
The cement production process emits carbon dioxide (CO2) through the decomposition of limestone into carbon dioxideand lime (CaCO3 ⇒ CO2 + CaO), and from the burning of the fuels necessary to create the high temperature in the kiln. Of all the CO2produced in the production of cement, about 60% comes from the chemical process described above and 40% from the burning of fuels. Approximately 700 kg of CO2 are emitted for every 1000 kg of cement produced. It is estimated that cement accounts for 5% of global CO2 emissions but the industry has a number of programmes in place to minimise this figure. Today clinker is ground with materials such as unburnt limestone to reduce the emissions footprint in production. CO2 is classified as agreenhouse gas (GHG).

Quiz questions

  1. The sustainability of industrial activities is a major environmental concern. true
  2. Another name for crushed rock is ‘aggregate’. true
  3. About 5% of the CO2 emitted during combustion in a cement kiln is from the chemical process involved. false
  4. Greenhouse gases absorb and emit radiation mainly in the ultra violet region. false
  5. Methane is a greenhouse gas. true
  6. 1 J (joule) is equal to 1 W (watt). false
  7. Nitrogen oxides are often referred to as NOx true
  8. SOx emissions are reduced by a Selective Non-Catalytic Reduction system. false
  9. Waste products are never used as fuel in cement plants.
  10. New types of blended cements can be produced at much lower temperatures than traditional cement. true

CRH

In its 2012 Sustainability Report, CRH states that it ‘ has progressed and developed in all areas of sustainability and sought to…