Effect of the method of mineralizer addition on the characteristics of Portland cement clinker

The article describes the studies carried out to determine the effect of mineralizer addition method on the properties of Portland cement clinker. In the course of research mineralizers were added to dehydrated raw slurry of ZAO Belgorodsky cement plant in two ways. It was found that the “split method” of adding mineralizers promotes formation of smaller alite crystals (2-8 μm in size) in comparison with the “conventional method” (8-30 μm) and burning the raw mixture without additives (4-25 μm). The compressive strength of the samples based on the clinker, obtained with adding mineralizer by the conventional method”, is 12 MPa higher, and by the “split method” - 19.6 MPa higher than that of the samples obtained from additive-free raw mixture. A change in clinker color to light gray when 2C2S · CaF₂ mineralizer is added by the “split method” was detected and analyzed. The discoloration occurs in the temperature range of 1300-1350°C. A color change in the cores of clinker lumps in the kiln of OAO Spasskcement from black to brown was detected when the content of R₂O and SO₃ in it increased due to a higher kiln speed, from 0.7 to 0.9 rpm.

Author: D.A. Mishin, S.V. Kovalev, V.G. Chekulaev

Section: Science and production

Keywords: clinker burning intensification, mineralizer, fluorspar CaF2, alkali metal salts, Na2O, R2O, clinker color, efficient use of mineralisers, the phenomenon of reducing the effect of the fluorspar