The aim of this thesis is the implementation of a lower-clinker cement type CEM II/B-M 42.5N, using separate grinding of limestone. In addition to the main research question whether a ce-ment with a lower clinker content and separately ground lime stone shows changes in strength development and workability compared to the co-ground product, the potential for energy and CO2 savings was also examined. For this purpose, preliminary investigations were carried out on cement of different fineness, produced without limestone in a ball mill with and without the use of activating grinding aids, and mixed with different amounts and types of limestone meal. These samples were examined in terms of strength, according to ÖNORM 196-1, chemical composition and workability using micro-concrete tests. In addition, the first grinding of pure limestone with a vertical raw mill was accompanied in order to determine the target fineness of the lime powder for industrial production by means of separate grinding. After grinding trials in which the limestone meal produced was conveyed to the limestone-free cement via a dosing system, industrial production began. Data regarding energy and CO2 savings were collected and the process settings and quality specifications were further optimized. During the industri-al production, sampling was carried out to confirm sufficient mixing quality of lime powder and cement. With the help of the preliminary tests, it was possible to show that no deterioration is to be expected in terms of strength and workability. The vertical raw mill is able to produce lime powder with a very regular fineness and the mixing quality of lime powder and cement proved to be sufficient. A CO2 saving by reducing the clinker content could be confirmed, but no energy saving.
|Translated title of the contribution||Implementation of a lower-clinker cement type CEM II/B-M 42,5N using separate grinding of limestone|
|Award date||30 Jun 2023|
|Publication status||Published - 2023|
Bibliographical noteembargoed until 08-05-2024
- Cement grinding
- Raw material grinding
- Separate Mahlung