Complex application of man-made raw materials for the manufacture of cement clinker

Abstract

At the article, the results of the investigation on the complex stowing of rich tonnage inputs in agro-industry and heat energy for the preparation of cement clinker are given. The object of the study was raw material mixtures for production of cement clinker based on the system of chalk — rice husk — fly ash. Calculations and analysis of the composition of raw mixtures were carried out using the created computer program "Clinker", which made it possible to quickly determine the rational ratio of components according to the given characteristics of the clinker. According to the results of computer calculations, the possible content of rice husk in chalk-based binary mixtures in the range of saturation coefficient KH = 0.80–0.95 is 55.7–60.1 wt. %, and fly ash — 23.9–26.6 wt. %, however, the numbers of silica and alumina modules do not meet the recommended n = 1.9–3.0 and p = 0.90–2.0 for cement clinker. When using 3-component mixtures, the possible total content of rice husk and ash in the range of KH=1.9–3.5 is from 39 to 52 wt. %. At the same time, the quantitative ratio of husk ash varies from 2.1 to 7.3. The possibility of obtaining normal-hardening cement of medium strength from a mixture containing 45.2 wt.% of man-made raw materials at a maximum firing temperature of 1400 °С has been experimentally confirmed. According to the X-ray phase analysis on the Philips Xapos;Pert PRO — MRD diffractometer, the relationship between the cement properties and the formation of the C3S-C2S-C2AS-CA crystal phase system during clinker firing was established. At the same time, the predominant development of calcium silicate phases is associated with the increased reactivity of amorphous silica, a product of heat treatment of rice husk. It was concluded that the integrated use of rice husk and fly ash as man-made raw materials in the mass-intensive production of cement clinker is a promising direction for the utilization of large-tonnage industrial waste.