The calcination process of converting CaCO3 to CaO releases 0.78 grams of CO2 for every gram of CaO produced, without even taking into account the additional emissions produced to create the electricity needed to heat the material. In 2010 , cement production was the second most common industrial source of carbon dioxide emissions followed by lime production in 3rd, with outputs of 30.5 Tg and 13.2 Tg of carbon dioxide respectively.1 In 2012, we introduced a new process to electrochemically convert CaCO3 into CaO without releasing CO2.2 Utilizing a molten carbonate electrolyte, non-precious metal electrodes can be used to convert CaCO3 into CaO, and oxygen at low voltages. The carbon product of the electrochemical process varies by temperature with graphite being produced at lower temperatures and carbon monoxide at temperatures above 850�C.3-4 With proper power matching, a single concentrated photovoltaic can supply enough electricity to run two electrolyzers in series, producing calcium oxide with no carbon dioxide emissions. Figure 1 shows the mobile outdoor unit that was used to perform the experiment using concentrated solar thermal heating and concentrated photovoltaic electricity. By introducing a new pathway to calcination, STEP Cement offers a sustainable and green process for the cement and lime production industry into the future.Figure 1: Mobile outdoor unit with 2 electrolyzers and a single CPV used for outdoor STEP Cement.References:U.S. Environmental Protection Agency; Inventory of U.S. Greenhouse Gas Emissions and Sinks, 1990-2010. 2012. Licht, S.; Wu, H.; Hettige, C.; Wang, B.; Asercion, J.; Lau, J.; Stuart, J.; STEP Cement: Solar Thermal Electrochemical Production of CaO without CO2 emissions. Chem. Comm., 2012  , 48, 6019-6021.Licht, S.; Cui, B.; Wang, B.; STEP carbon capture- The barium advantage; J. of CO2 Utilization, 2013  , 2, 58-63.Licht, S.; Wang, B.; Ghosh, S.; Ayub, H.; Jiang, D.; Ganley, J.; A new solar carbon capture process: solar thermal electrochemical photo (STEP) carbon capture, J. Phys. Chem. Lett., 2010  , 1, 2363-2368.

Production of carbon-dioxide free cement from only solar power, the solar thermal electrochemical process (STEP) for converting calcium carbonate to calcium oxide

248th National Meeting (2014)

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