Extracting lime with solar power

Researchers at George Washington University have invented a solar-powered process to extract lime from limestone that does not emit any carbon dioxide.
It has been demonstrated in a proof-of-concept device. 
The researchers estimate that the process could cost less than the conventional one and eliminate a major global source of carbon dioxide emissions. 
Rather than the conventional method of heating up limestone until it releases carbon dioxide, this new process uses a combination of heat and electrolysis, which produces lime, oxygen, and either carbon or carbon monoxide, depending on the temperatures used. 
The researchers built a device that includes three Fresnel lenses for concentrating sunlight. Two of those heat a mixture of lithium carbonate and limestone (calcium carbonate). The third focuses light on a high efficiency solar cell, which provides the electricity needed to electrolyze the carbonate mixture. 
High temperatures reduce the amount of electricity needed and cause the lime to precipitate out of the mixture, making it easy to separate. However, the device works only when it’s sunny, and intermittent operation isn’t ideal for an industrial process. 
The researchers propose using molten salt to store heat, a system used in some solar thermal power plants. If it works this will allow the process to run day and night.
Source: Aggregate Research

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