Grinding aids evaluation by Zeisel mill

Cement grinding is an energy intensive process. Electrical energy consumed for grinding clinker is typically around 40 % of the global electrical energy used in cement production. Specific industrial power consumption depends on clinker composition and ranges approximately from 30 to 80 KWh/t. Conventional-type mill has very low yield which partly justifies the large energy consumption. Additives permit to improve grinding efficiency and/or reduce energy consumption with positive effect on cement quality too. The effectiveness of grinding aids is difficult to be evaluated by laboratory tests and a final judgement on the advantages of their use can be given only by carrying on industrial tests. Nevertheless laboratory tests are necessary for preliminary evaluations of grinding aids efficacy and development of new formulations.
The present work is aimed at investigating the possibility offered by Zeisel mill in order to forecast grinding aids effectiveness. Till now this mill has been mainly used to measure clinker grindability without the presence of cement additive. In a first part the paper presents grindability data obtained with three glycol-type grinding aids and their resulting ranking. In a second part a hybrid formulation, i.e. based on ingredients increasing specially mill output and selected among the previous ones and on a chemical increasing also compressive strength, is evaluated. Quantification of the energy saving is calculated at different Blaine values. The additive effect is compared with that of a commercial product not only at lab scale but also at industrial level. The results are in good agreement. Possibilities and limits of Zeisel mill are described.

Author: M. Goisis, C. Capone, G. Zonca, A. Capelli

Section: Science and production

Keywords: Zeisel mill, grinding aid, additive, glycol, amine