Global cement production is expected to continue increasing at 4 percent a year. By 2013, the total will be 3.5 billion metric tons, worth about $246B.
Concrete or its equivalent, represents a terrific opportunity to sequester pollution, including CO2.
Recall Portland cement is named after a quarry in Britain, where natural cements were exploited in the 19th century. Wikipedia reminds us that it consists at least 2/3 of calcium silicates (3CaO.SiO2 and 2CaO.SiO2). (Did you notice an absence of carbon in this chemistry?
'Pollution' may be key ingredient in concrete mixtures, says Missouri University of Science and Technology researcher. Their research has been sequestering fly ash into concrete. Recall fly ash is the particles that rise from flue gases after combustion of fossil fuels. Fortuituously for concrete, it has a high concentration of calcium oxide and silicon dioxide, which are part of the formula for Portland cement. Wikipedia tells that fly ash must now be captured as part of the Environmental Protection Agency (EPA) rules instead of released to the atmosphere.
The researcher explains that presently cement is a mixture of 35 to 40 percent fly ash. Their research is increasing the fly ash content to 70 percent. Generally this additive reduces setup and hardening times, especially in colder temperatures.
Last June I had blogged about Chemical Pathways for Carbon Sequestration. Simply, the idea is to inject CO2 into magnesium silicate at a high temperature. It forms a hard substance similar to concrete that locks the CO2 into the compound permanently. The primary obstacle is the energy required to create the high temperatures. Mmm. The Next Generation Nuclear Reactor would be ideal for producing the heat necessary for safely sequestering carbon dioxide.