A STUDY ON THE METHODS OF EVALUATING THE FINENESS OF GROUND GRANULATED BLAST-FURNACE SLAG

Adequate methods for evaluating the fineness of ground slags were sought using various slag samples which were prepared by grinding three granulated slags by either a jet mill or ball mill to about 3000-8000cm2/g Blaine surface. It was confirmed that the conventional Blame air permeability method could be employed to evaluate the relative fineness of ground slags, provided that their raw materials and grinding mill were maintained the same. A proposal was made to select the amount of sample for the Blaine method in such a way that its sample bed could be formed with a force of 3-5kgf. As an index for evaluating the fineness of all kinds of ground slags, the specific surface areas calculated from their particle size distributions, which were analyzed by a laser-beam method, were considered to be most appropriate.