INVESTIGATIONS ON INTRODUCING SI AND MG INTO BROWNMILLERITE - A RIETVELD REFINEMENT

Brownmillerite (commonly C(4)AF) was synthesized in a laboratory furna ce. The product was examined by X-ray powder diffraction and the struc ture was refined by the Rietveld method. Further syntheses were made u nder various conditions by substituting Fe2O3 by MgO + SiO2 according to the formula C(4)AF(1-x)M(x)S(x). All samples were examined by X-ray diffraction and quantified by Rietveld method due to their content of Brownmillerite, C2S and MgO. All results show that the whole SiO2 con tent could be calculated as C2S. MgO could be partially found as peric lase. Brownmillerite shows a shift of lattice parameters according to the solid solution series C(6)A(2)F - C2F.