In a process and a plant for producing products, especially cement and/or quicklime from carbonate-containing raw materials, the carbon dioxide formed is not released into the atmosphere, but instead, optionally after conversion to carbon monoxide, is converted to sodium formate, and the sodium formate thus formed is converted to sodium oxalate. The sodium oxalate thus formed is converted by reaction with potassium hydroxide (slaked lime) to calcium oxalate which can be used as a concrete aggregate or else in another way.
