Ordinary Portland cement requires a kiln temperature of 2,642ºF. In order to reduce energy use, ecocement uses magnesia (magnesium oxide) in its mix in order to reduce the firing temperature to 1,382ºF. Another technique is to produce calcium carbonate by using the wasteflue heat and carbon dioxide from other processes. In addition, recycled aggregate such as fly ash (a by-product of coal-fuelled power stations) can be used, which further reduces the concrete’s embodied energy. Furthermore, ecoconcrete, like lime mortar, takes up carbon dioxide from the atmosphere.