Utilization of low-cost celestite ore in the production of high-quality calcium-strontium aluminate refractory cement

Maximize the use of municipal waste generated by the hydrogen peroxide industry in the production of high-quality refractory CAC

“…4 ) and conversely the bulk density enhanced (Fig. 5 ) with the addition of waste alumina due to the higher density of corundum (D = 3.88–3.99 g/cm 3 ) 27 – 29 relative to that of limestone (D = 2.71 g/cm 3 ) 29 – 32 . In contrast, bulk density declined and apparent porosity increased unusually with the increase in alumina content beyond CA60.…”

“…= 1390 °C) 34 – 37 formed in “CA60” specimens. Regarding the effect of sintering temperature on the densification behavior of sintered samples “CA40-70”, there was an increase in bulk density and a decrease in apparent porosity with the enhancement of sintering temperature from 1250 to 1450 °C due to the phenomenon of sintering densification and the gradual sedimentation of the formed phases in the voids, which reduces the apparent porosity and enhances the bulk density 12 , 29 , 38 – 40 . Among the tested samples, the “CA60” specimen sintered at 1450 °C revealed the lowest apparent porosity (0.9 vol%) and the highest bulk density (2.7 g/cm 3 ), revealing a semi-molten, fully-dense structure.…”

“…The castables prepared with CA60 cement have shown a higher strength at 110 °C with 4.5 MPa when compared to the commercial CAC at the same temperature (1.8 MPa). With further increase in curing temperature, the strength of the castables has collapsed due to the consequence of evaporation of water as the temperature increased; followed by extra creation of pores and lower strength of the refractory castables 29 , 47 . This huge difference in strength between CA60 and commercial cement has promoted and stated the industrial and economical value of the manufactured CA60 cement, where a higher strength castables with fast-setting time can be achieved by applying prepared cement from waste instead of commercial cement.…”