Abstract
Test pieces of the compositions corresponding to several points of the MgO-Al2O3-SiO2 system were prepared and tested for corrosion on the phlogopite melt.The compositions of the test pieces are as follows:SiO2 Al2O3 MgO R2O Ig. loss% % % % %SFA 13.9 52.8 32.1 0.4 1.5SFB 10.7 59.0 30.1 0.3 1.4SP 8.6 45.0 44.7 0.2 2.9PF 24.7 16.8 55.1 0.4 2.5FP 31.0 12.8 53.1 0.6 3.4CM 30.6 63.2 7.0 0.8 0.4Test pieces were moulded by the extrusion method and heated to 1600-1800°C in a cryptol furnace. They were dipped in the synthetic phlogopite melt and maintained at 1400°C for 5 hours. When the specimens were cooled, they were observed with unaided eye and under a petrographic microscope.Specimens of SF composition were composed of granu lar spinel crystals and poikilitic forsterite crystals. They were attacked by the melt, when their degrees of water absorption were greater than 2-3%. But spinel crystals suffered any change and separated into the melt.Specimens of SP composition were composed of granular crystals of spinel and periclase and poikilitic forsterite crystals. They were not attacked appreciably even when the degree of water absorption was 8%. Periclase crystals reacted with the melt to separate forsterite needles, i.e. the melt near the crucible wall was saturated with forsterite, so the forsterite crystals of the wall were attacked no more.Specimens of CM composition were composed of corundum crystals with a small amount of glassy matter. Corundum reacted with the melt to separate spinel crystals. A dense layer of the precipitated spinel crystals was found along the wall of the specimens. The degree of water absorption of the specimen should be smaller than 1-2% to stand for the melt corrosion.Specimens of FP composition were composed of a large amount of granular crystals of forsterite and a little amount of granular crystals of periclase. The matrix of the specimen was attacked very easily. The forsterite crystals became separately and dispersed into the melt finally. Periclase was solved in the melt and forsterite crystals grew larger. The degree of water absorption of the specimen should be less than 4-5% to stand for the melt.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
