A centrifugal method of making small pots of electrically fused refractory materials

The present paper describes portion of a research on the alloys of iron, which being carried out at the National Physical Laboratory, under the direction Dr. W. Rosenhain, for the Ferrous Alloys Research Committee. Papers dealing with other portions of the work have been published in the ‘Journal the Iron and Steel Institute.’ In the course of a research on the alloys of iron and oxygen, it became necessary to hold two immiscible layers of molten iron and iron oxide at a temperature of 1,540°C. It was not found possible to hold the liquid oxide at this temperature in any pot made by bonding together previously shrunk fractory material in the usual manner; such refractories as were not directly attacked became “wetted” by the oxide, which was absorbed and an out through the pores of the pot. Experimental melts of very small quantities of oxide were made in small hollows in pieces of solid fused magnesia having a glazed surface; these showed practically no absorption of the oxide by the magnesia. Attempts were therefore made to produce a pot of pure magnesia, having an inner surface completely glazed by fusion, in the heat of a electric arc. The experiments were ultimately successful, and a method as been developed for making well-shaped pots having a glazed internal surface of fused material not only in magnesia (M. P. 2,800°C.), but also in alumina (M. P. 2,050°C.), zirconia (M. P. 2,700°C.) and tungsten metal (M. P. 3,300°C.). The time required to produce a pot (having procured the material to be fused in the form of a powder) is about 15 minutes, the time actual fusion under the arc being about 2 minutes. Two views and ertical section of magnesia pots made by the method to be described are hown in fig. 1 (p. 288).