Cemex finds alternatives

February 22, 2011

February 22, 2011
Sarah Murray

Journalist, author, speaker

Sarah Murray is a specialist writer on business, society and the environment and a regulator contributing author for the Economist Group. 

One way some industries can reduce energy consumption is to use materials that require less energy to manufacture. For the cement industry, clinker4, which makes up around 90% of the mix, is the most energy-intensive input. So to cut its energy use, Cemex is re-thinking how it produces cement. Because clinker must be heated to a certain temperature, making it hard to reduce its energy consumption, the Mexico-based cement maker has taken another approach. “We’ve developed sources that mean we can increase the use of non-clinker cementitous materials, lowering our clinker factor,” says Luis Farias, senior vice-president of energy and sustainability at Cemex. “The less clinker you use, the less [embedded] energy the cement contains.”

Materials Cemex uses include active minerals derived from industrial waste, such as slag from glass furnaces or steel mills and fl y ash, a by-product of power plant coal combustion, as well as naturally active materials such as volcanic ash. These materials allow Cemex to reduce the amount of clinker in its cement by up to 30%.

At the same time, the company is tackling the carbon footprint of the clinker it does use, seeking renewable sources of energy such as wind and hydropower and power generated by converting waste to energy. “We’re doing something with direct emissions, but also indirectly with the source of the power that we buy,” says Mr Farias.

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