Overall the ZAP-C 3 system can be described as a process for conversion of two waste material (BOS slag and CO2) into two valuable products (CaCO3 and volumetrically stable aggregate) that represent permanent sequestration of CO2. It is important to note that unlike in-situ processes the ZAP-C 3 system allows for direct verification of CO2 sequestered through simple analytical methods. Furthermore, unlike other ex-situ methods the ZAP-C 3 system does not rely on slow natural mineralization, or mining of minerals, and importantly allows for all water to be 100% recycled since it represents the catalyst in the reaction.