Crystallization of ash melts

The crystallization behaviour of compositions in the systems CaO-Al2O2-SiO2r CaO-MgO-A 1202-8109 and CaO-Al202-8102"iron oxide relevant to coal ash compositions has been studied. The observations have been compared with the devitrification behaviour of both eastern and western type coal ashes determined under laboratory conditions. Results show that the crystallization of ash melts is well represented by the systen CaO-FeO-A 1202-8109. The quaternary systen has been constructed from literature data as planes of constant FeO content (5-30 wt% at 5% increments) and used to predict the behaviour of boiler deposits. 

Crystallization of ash melts The results of the crystallization of the three ash melts studied are listed in Table V. The only phase observed to precipitate for the western type ashes was anorthite (CaO.A 1203.23102) despite lengthy treatment. The eastern type ash showed different behaviour with mullite (3A1203.23102) as the... 

Table IX. Comparison of observed crystallization of ash melts with that predicted from relevant phase diagrams.

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