X-ray study and computer simulation of mechanically activated pseudowollastonite structure

Abstract

In this paper we report on X-ray studies on amorphization of pseudowollastonite following 30 min mechanical activation using a centrifugal planetary mill AGO-2 in atmospheric air. In addition, milling resulted in chemical reaction which led to the formation of calcium carbonate and silica. In general, the chemical composition of the sample corresponded to the formula CaSi_0.997C_0.014O_3.02. Theoretically calculated scattering intensity for a model of mechanical mixture corresponded to the following ratio: 0.75 scattering intensity of the cluster consisting of four unit cells of pseudowollastonite disordered in a molecular dynamic experiment; 0.25 scattering intensity of the cluster consisting of one unit cell of CaCO₃; 0.25 scattering intensity of the cluster consisting of one unit cell of α-SiO_2. The R-factor for scattering intensity I(s) was 5.5%. The curve of s-weighted interference function H(s) calculated for the model coincided with the experimental curve. Characteristics of tetrahedra arrangement in the initial pseudowollastonite cluster and in the same cluster after molecular dynamic were calculated by the method based on the searching for a coordination polyhedra in the clusters and the constructing of graphs.