Cement slurry from electro-phosphoric slag

Abstract

Possibility to obtain high alite Portland cement of alternative raw materials was established by complete replacement of clay component with electro-phosphoric (EPS) slag. This technology allowed disposal of considerable volume of slag with production of high grade cement and reduction of CO2 emissions. Fuel saving was about 15 % increase in productivity of kiln was 10−15 %. It was detected after industrial tests that some rheological properties of slag were unknown. We studied properties of limestone-residual slag, aimed at production of clinker with alite content 69.6 and 65.4 %. EPS slag was weak structuring element at the initial stage of coagulative structuring. An increase in the volume concentration of solid phases led to an increase in viscosity, dynamic shear stress, and plastic strength. With an increase in concentration by 3 % from 35 to 38 %, fluidity decreased by 20 mm, and mobility by 1.3 times. Increase of bulk concentration of solid phases led to increase in viscosity, dynamic stress viscosity, and plastic strength. With the increase in concentration by 3 % from 35 to 38 %, fluidity had been decreased by 20 mm, and mobility by 1.3 times. Further growth of concentration led to reduction of these indicators by an order. Coarse limestone-residual slag with moisture content 37 % preserved its mobility during 26 days. Under static conditions, critical structural strength (100 g.cm2) of slag was achieved during 24 days. In case of proper mixing, duration of slags' mobility shall be increased. Therefore 37 % can be recommended for lower limit of slag moisture.