the number of cycles used and the type of limestone used. Disposal routes Proposed disposal routes of waste sorbent include: Landfill; Disposal at sea; Use in cement manufacture; Use in flue gas desulfurisation (FGD). The lifecycle CO2 emissions for power generation with CaL and the first three disposal techniques have been calculated. Before disposal of the CaO coal power with CaL has a similar level of lifecycle emissions as amine scrubbing but with the CO2-absorbing properties of CaO CaL becomes significantly less polluting. Ocean disposal was found to be the best, but current laws relating to dumping waste at sea prevent this. Next best was use in cement manufacture, reducing emissions over an unabated coal plant by 93%. Use in cement manufacture Portland cement is approximately two-thirds calcium oxide by mass and its manufacture is responsible for approximately 8% of the world's CO2 emissions. 60% of this CO2 comes from the calcination of calcium carbonate as shown earlier in this article, and the other 40% from fossil fuel combustion. By replacing some or all of the calcium carbonate entering the plant with waste calcium oxide, the CO2 caused from calcination can be avoided, as well as some of the CO2 from fossil fuel combustion. This calcium oxide could be sourced from other point sources of CO2 such as power stations, but most effort has been focussed on integrating calcium looping with Portland cement manufacture. By replacing the calciner in the cement plant with a calcium looping plant, it should be possible to capture 90% or more of the CO2 relatively inexpensively. There are alternative set-ups such as placing the calcium looping plant in the preheater section so as to make the plant as efficient as possible. Some work has been undertaken into whether calcium looping affects the quality of the Portland cement produced, but results so far seem to suggest that the production of strength-giving phases such as alite are similar for calcium looped and non-calcium looped cement. Direct Separation Technology Calix Ltd has developed a new type of kiln that enables the from the calcination process to be driven off as a pure stream. Calix achieves this by calcining finely ground CaCO3 continuously down vertical reactor tubes. The reactor tubes are heated from the outside using electricity or fuel ensuring the stream is pure and not contaminated with air or combustion products. This technology has been successfully piloted in