| 摘要 |
<p>The mixt. contains two or more oxides which are insulators when cold, where a principal cpd. (I) is the oxide of a metal which is conducting when cold, and reacts strongly and exothermally with O2 when heated; this oxide has a higher m.pt. than the other oxides. The mixt. is fed into a furnace formed by a circular row of vertical tubes. The tubes are made of a non-ferromagnetic material conducting heat and electricity, and are insulated from each other; a coolant flows through the tubes, which are located on a cooled hearth. The lower part of the tubes is in a helical induction coil; and the initial charge consists only of oxide (I) and turnings or grains of the metal in this oxide (I); when this charge has melted, the oxide mixt. is added. Used esp. where (I) is Al2O3, ZrO2 or MgO; and where the melt can be continuously cast directly from the furnace.</p> |
