CENTRIFUGAL LIQUID WALL FURNACE

The construction and operation of a centrifugal liquid wall furnace is described. A symmetrical molten cavity was formed within a hollow, thick-walled core of alumina, zirconia or magnesia by convective heating from an arc plasma jet. The core was rotated so that the liquid layer or layers formed from core material and from materials dispensed into the furnace were held centrifugally against the cavity wall. The furnace was used to distil various oxides including alumina. In general, submicron-sized aerosols were obtained which require further investigation. X-ray diffraction showed that distilled alumina contained δ-alumina and probably γ-alumina. Distillation of impure alumina resulted in a near hundredfold increase in the proportion of gallium. Examination of a fused alumina core usually revealed the growth of a crystalline tube from within the cavity against the plasma jet. This was at least partly due to crystal growth from the vapour-phase, but there was evidence of partial melting or remelting of the tube possibly by radiation from the arc column of the plasma jet. © 1969 Chapman and Hall.