The effect of small additions of Sodium Hexa Meta Phosphate (SHMP) in enhancing the flow properties of low Cement Castable are well documented. In our study, we will notice a distinct change in physical properties with the addition of SHMP. The physical properties are improving noticeably on the addition of SHMP with an increase in incremental amounts (from 0.2% to 0.5%). The physical properties are improving on the addition of SHMP, but also there seems to be an effect due to the bulk alumina and iron content of the raw material mix, which also affects the flow properties. The other additive such as Sodium Aluminate with SHMP also show similar effects. However, STPP not only affect the flow, but also the physical properties with SHMP and not considered good enough. The change in physical properties only with SHMP are noticeable, in the increase in Bulk Density, the Cold Crushing Strength (CCS), and flow properties at low temperature (110°C), but at high temperature of 1350°C, a sizeable increase in Cold Crushing Strength is noticed, with low values of Permanent Linear Change (PLC, %). This additive possibly influence the development of a superior low temperature matrix formation with refractory aggregate and binder distribution, at the time of water added to the castable material, and due to ionic interaction and repulsion, with the developing flow pattern modified to suit the ease of good matrix formation, with low water for casting and good binder strength. In this paper, we will study the effect of these additive in sequential addition, and the changes observed in physical properties, flow pattern for low cement castable LCC-70 and 80 per cent alumina base, and high alumina conventional castable (alumina-90%).
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