Abstract: The invention is directed to improved centrifugal rotary electric furnaces which are used for the heating and or fusion of minerals, such as quartz, and other materials having a high melting point. The furnace includes a generally cylindrical furnace shell and a decreasing diameter stepped end member attached to each end of the shell which is intended to more closely conform the end of the furnace to the shape of fused ingot or melted charge formed inside the furnace, while still providing a sufficient depth of unmelted charge between the fused or melted material and the end member to insulate the end member from excessive heat and the warpage and other damage caused thereby.

Abstract: A furnace construction capable of withstanding temperatures in excess of 3500.degree. F. A uniquely suspended floor structure permits thermal expansion to occur as required within the furnace while permitting the admission of a cooling fluid to metal plate members therewithin. The furnace chamber is provided with an open bottom which is closed with a refractory raw material in a container and sealed by a skirt member attached directly to the superstructure of the furnace which penetrates the refractory material. Track and elevation means permits the refractory filled loaded container to be pushed into position and lifted until it seals the furnace chamber and the refractory material is heated above its melting point to form a fused ingot. Thereafter, the fused ingot is lowered in the container onto the track means and pushed away while another container of raw material is pushed into position.