Reduction of CO2 emissions during cement clinker burning; part 1 = Ein Beitrag zur Reduzierung der CO2-Emissionen beim Zementklinkerbrand; Teil 1

The aim of the research project entitled "New technology in cement production for reducing CO2 emissions" sponsored by the German Federal Environmental Foundation was to lower the CO2 emissions during clinker burning. A possible reduction, relative to an industrial example, of up to 21 % in the carbon dioxide emissions due to the raw materials was identified. The CO2 emissions caused by the fuel can be reduced by about 13 % by lowering the energy requirement for clinker burning. Implementation was achieved by partial replacement of the rock used for Portland cement clinker production by by-products from other industrial processes (e.g. steel production, power generation from lignite) as raw meal components. The environmental relevance and the industrial availability have been taken into account. The burning process for cement clinker was carried out on a laboratory scale in a gradient furnace. The clinker produced in the trials and the suitability of the raw meal mixes were evaluated by chemical and quantitative X-ray phase analysis. CO2 balances were established as crucial criteria for material selection. Clinker for determining the technical cement parameters was produced from an alternative raw mix and a reference meal. Assessment of the cement quality showed that when industrial by-products are used it is possible to achieve hardening and workability properties that are equivalent to those achieved when using Portland cement clinker from conventional raw meal mixes