Research And Application On Using Magnesium Slag To Prepare Cement

Magnesium slag (MS) discharged from Pidgeon Process, which is used to extract magnesium from dolomite, could be utilized as cement raw meal to accelerate the formation of clinker and improve the quality of cement clinker.In this paper, the calcination reaction kinetics of cement raw meal blended with MS was investigated. The burnality of raw meals with different MS content were tested, and the process and mechanism of clinker formation were analyzed with the aids of XRD, and petrographic analysis. A set of detailed MS blending strategies were tried in the production of a dry-process plant.The results indicated that blending MS could decrease the apparent activation energy of clinker formation. The rise of the blending content increased the fall amplitude, which is helpful to depressing the reactive temperature and accelerating the formation of clinker. Adding proper quantity of MS in raw meal could improve the burnability of raw material, cause a great deal of tricalcium silicate form at the temperature range from 1250℃ to 1350℃, and reduce the f-CaO content in clinker. The minerals originally in MS such as C₂S induced crystallization. The Fe²⁺, F- and MgO existed in MS debased the viscosity of liquid phase at high temperature, facilitated the calcinations of CaCO₃ and the formation and crystallization of C3S. All of these proved that MS could be used as raw material and mineralizer in Portland cement production. The clinker obtained from this study appeared good crystalline, that is, the A mineral and B mineral grown well, A mineral presented as hexagonal plate or short pole with regular arrises and the f-CaO was little.Industrial experiments revealed that the appropriate content of MS blent in raw meal is about 10%. Proper blending of MS could remarkably enhance the strength of clinker at every age, and make sure normal setting time and eligible stability of clinker. On the strength eligible, the blending amount of admixture in cement could be increased notably when producing cement with this kind of clinker.