Low cement castable based on auto combustion processed high alumina cement and mechanochemically synthesized cordierite: Formulation and properties

Nano high alumina cement was prepared by an auto combustion method which was a self-propagating high temperature synthesis. Metal nitrate precursors were used in this process and thermal reactions were done at 1000 °C. Prepared high alumina cement was tested for its cementing properties and mechanical behavior. These properties were compared with commercialized CA-25 C high alumina cement. In a separate process, cordierite was mechanochemically synthesized by mixing proper amounts of kaolin, talc and gibbsite and then grinding in a high-speed planetary mill to reduce the initial particle sizes of mixes. The prepared mixes were calcined at different temperatures. In order to study the effects of process variables, the powders were analyzed by XRD and SEM. Based on XRD results it was concluded that the cordierite mixture was amorphous to XRD by high energy grinding of the mixes at 600 rpm for 30 min. Cordierite was successfully produced at temperatures as low as 1150 °C. Low cement castables were formulated introducing the prepared HAC as a binder phase in the cordierite matrix with further addition of silicon carbide for enhancing mechanical properties. Formulated LCC briquettes were analyzed for their physico-mechanical properties including bulk density, apparent porosity, cold crushing strength and cold modulus of rupture.