Abstract: An apparatus for growing shaped single crystals of high-melting transparent metal compounds has a sealed chamber (1) having inside thereof a heat insulating unit (2) with a heater (3) in the form of a sleeve accommodating a crucible (5), mounted for axial reciprocations in the sleeve a shape-imparting member (6) in the form of a cylinder having capillary orifices for supplying a melt (11) from the crucible (5) to a crystallization zone (14) of a single crystal (7) located above an upper end (13) of the shape-imparting member (6) which is configured to have a cross-sectional shape of the single crystal (7). The heater also accommodates horizontally extending planar thermal shields (23) having coaxial openings (25) for the single crystal (7) being grown to pass therethrough, and a thermal shield (24) in the form of a hollow cylinder mounted in the openings of the planar thermal shields.

Abstract: A process for growing shaped single crystals of refractory optically transparent metal compounds comprising melting a starting stock in an inert gas atmosphere under the effect of heat evolved by a heater; the melt is continuously fed into a crystallization zone through a capillary system of a shaping unit, followed by pulling a single crystal from the crystallization zone and cooling thereof. Prior to melting of the starting stock one control particle thereof is placed into the crystallization zone and at the moment of melting of said particle the heater power P is recorded. Melting of the starting stock is conducted at a heater power of (1.04-1.1)P, fusing of the seed--at a power of (1.03-1.08)P, building-up of the single crystal--at a power of (1.02-1.08)P; pulling--at a power of (1.02-1.22)P.

Abstract: Disclosed is an ore-smelting electrical furnace bath, in which smelting is accomplished with electrodes buried into the melted slag, comprising an externally cooled metallic jacket, a lining forming the walls and the bottom of the bath, and a sealing layer interposed therebetween. The walls of the bath in the melted slag zone are made from graphite-reinforced refractory blocks having a thickness at which the total thermal resistance of these blocks and of the sealing layer ranges from 0.01 to 0.09 m.sup.2 hr.deg./kcal. The lower portion of the aforesaid walls and the bottom are made from refractory carbon blocks.

Abstract: During the process of pulling sapphire tubes from a melt with the aid of a seed, the longitudinal temperature gradient in the zone between the solidified front and the region of pulling where the temperature is between 1850 and 1900 deg. C. is maintained not in excess of 30 deg. C./cm. The tube so grown is annealed at a temperature between 1950 and 2000 deg. C. by increasing the temperature at a rate of 30 to 40 deg. C./min and keeping the tube at said temperature during a period between 3 and 4 hours. After that the tube is cooled down to room temperature at a rate of 30-40 deg. C./min.Disclosed is also an apparatus which enables said temperature gradient to be maintained while pulling the tube.

Abstract: A method for smelting charge materials in an electric arc furnace consists in that a bath of the electric arc furnace is loaded with the charge materials, electrodes of the electric arc furnace are supplied with an alternating current, the charge materials are melted, redox reactions are conducted and a finished melt and a slag are tapped, the alternating current of industrial frequency supplied to the electrodes of the electric arc furnace being first converted to one of a frequency ranging between 0.05 and 30 Hz. An apparatus for carrying into effect the above method comprises an electric arc furnace, in a bath of which are inserted electrodes. A secondary winding of a transformer is coupled with the electrodes through power supply arrangements.

Abstract: During the process of pulling sapphire tubes from a melt with the aid of a seed, the longitudinal temperature gradient in the zone between the solidified front and the region of pulling where the temperature is between 1850 and 1900 deg. C is maintained not in excess of 30 deg. C/cm. The tube so grown is annealed at a temperature between 1950 and 2000 deg. C by increasing the temperature at a rate of 30 to 40 deg. C/min and keeping the tube at said temperature during a period between 3 and 4 hours. After that the tube is cooled down to room temperature at a rate of 30-40 deg. C/min.Disclosed is also an apparatus which enables said temperature gradient to be maintained while pulling the tube.

Abstract: The apparatus comprises a cooled mould mounted on a bottom plate, a roof mounted on the mould, non-consumable electrodes connected to a power source and introduced into the melting chamber of the mould through sealed apertures in the roof, and a liquid metal pouring system incorporating a metal conduit with a funnel mounted in an aperture in the roof and an inclined chute positioned above the metal conduit funnel. The roof is provided with a gas exhaust pipe and with input funnels for feeding slag and alloying admixtures. The junction between the roof and the mould is sealed. The non-consumable electrodes are arranged around the circumference of the melting chamber for vertical movement, whereas the inclined chute is adapted to move in the horizontal plane.The enclosed melting chamber makes it possible to reduce heat losses and to maintain a controlled atmosphere within the mould.