Production system for a hafnium crystal bar and the method thereof

Abstract

The present invention discloses a production system for a hafnium crystal bar and the method thereof. The technical program includes a power supply unit with large DC current, an iodizer, a molybdenum insulator provided inside the iodizer, a thermostatic device, a cooling unit, a vacuum unit, an iodine box for iodizing the iodizer, an electrode unit electrically connected to the power supply unit, wherein the electrode unit is disposed above the iodizer, a crystallization unit provided inside the iodizer, wherein the crystallization unit is connected to the electrode unit, and a rough hafnium provided between the iodizer and the molybdenum insulator. The thermostatic device is a structure with an insulation layer provided outside an inner tank, and an electric heating wire is provided between the inner tank and the insulation layer. The inner tank of the thermostatic device is filled with a saline solution.

We claim: 
     
         1 . A production system for a hafnium crystal bar comprising:
 a power supply unit with a large DC current;   an iodizer;   a molybdenum insulator provided inside the iodizer;   a thermostatic device capable of accommodating the iodizer;   a cooling unit for cooling the iodizer;   a vacuum unit for vacuumizing the iodizer;   an iodine box for adding iodine into the iodizer, wherein the iodine box is controlled by a ball valve;   an electrode unit electrically connected to the power supply unit, wherein the electrode unit is disposed above the iodizer;   a crystallization unit provided inside the iodizer, wherein the crystallization unit is connected to the electrode unit; and   rough hafnium provided between the iodizer and the molybdenum insulator;   wherein, the thermostatic device is a structure with an insulation layer provided outside an inner tank, and an electric heating wire is provided between the inner tank and the insulation layer, wherein the inner tank of the thermostatic device is filled with a saline solution;   wherein the iodizer is fixedly mounted inside the inner tank of the thermostatic device and is completely immersed in the saline solution;   wherein the thermostatic device is further provided with a thermocouple extending into the saline solution, wherein the thermocouple is used for measuring a temperature of the saline solution.   
     
     
         2 . The production system for a hafnium crystal bar according to  claim 1 , wherein the electrode unit comprises an electrode rod made of a chromium-zirconium-copper rod, a molybdenum electrode rod located below the electrode rod, an electrode tip located at a bottom of the molybdenum electrode rod, wherein the molybdenum electrode rod is connected to the electrode rod by a screw thread, wherein a core wire of the crystallization unit is a hafnium wire and both ends of the core wire are connected to the electrode tip. 
     
     
         3 . The production system for a hafnium crystal bar according to  claim 2 , wherein a bottom of the molybdenum electrode rod is fixedly connected to a cover of the iodizer through a molybdenum sleeve, and an insulating ferrule is arranged between the molybdenum electrode rod and the molybdenum sleeve. 
     
     
         4 . The production system for a hafnium crystal bar according to  claim 2 , wherein a lower portion of the molybdenum electrode rod is fixedly provided with an anti-discharge ceramic piece having an inverted L-shaped cross section. 
     
     
         5 . The production system for a hafnium crystal bar according to  claim 1 , wherein a core wire fixing device is provided inside the iodizer, wherein the core wire fixing device comprises a molybdenum rod connected to the cover of the iodizer, a molybdenum plate connected to the molybdenum rod, and an insulating ceramic piece connected to the molybdenum plate, wherein a molybdenum wire for fixing the core wire is fastened to the insulating ceramic piece. 
     
     
         6 . The production system for a hafnium crystal bar according to  claim 1 , wherein the cooling unit comprises a thermally conductive fuel tank, a cooling coil peripherally provided around an outer wall of the iodizer, a condenser, and a circulating and stirring system in the thermostatic device; wherein the circulating and stirring system comprises a circulating pipe provided on a side of the inner tank of the thermostatic device, wherein an agitating shaft is provided in the circulating pipe; wherein an agitating vane is provided at a lower part of the agitating shaft, and an upper part of the agitating shaft extends outside of the circulating pipe and connects to a output shaft of a motor. 
     
     
         7 . The production system for a hafnium crystal bar according to  claim 1 , wherein a cover of the iodizer is fixedly connected to a flange of a body of the iodizer, wherein a sealing ring and a secondary sealing device are arranged between the cover of the iodizer and the flange. 
     
     
         8 . The production system for a hafnium crystal bar according to  claim 1 , wherein the vacuum unit is connected to the iodizer through a vacuum valve, wherein the vacuum unit includes a triplex pump, wherein a primary pump is a mechanical pump, a secondary pump is a lobe pump and a tertiary pump is a diffusion pump. 
     
     
         9 . A method for producing a hafnium crystal bar, comprising the following steps:
 a. drying rough hafnium;   b. adding the rough hafnium into a gap between an inner wall of an iodizer and a molybdenum insulator;   c. hanging a core wire onto an electrode tip and fixing the core wire into a core wire fixing device;   d. hermetically connecting a cover of the iodizer and a body of the iodizer;   e. opening a vacuum valve to connect to the vacuum unit, and vacuumizing to less than 6.0×10 −2  Pa, wherein closing the vacuum valve when a tested pressure rise rate is less than 2.0 Pa/h;   f. adding iodine into the iodine box;   g. vacuumizing the iodine box to less than 6.0×10 −1  Pa, simultaneously closing a ball valve;   h. sealing the iodine box, and closing the vacuum valve;   i. hoisting the iodizer integrally into a thermostatic device, wherein the thermostatic device has been heated to 240-300 C.°;   j. connecting the power supply unit to heat the core wire, wherein a current is set within 30-60 A and a voltage is set within 80-120V, and a corresponding temperature of the core wire is 1400-1600 C.°;   k. opening the ball valve, adding iodine into the iodizer, the iodine reacting with the rough hafnium rapidly to produce hafnium tetrafluoride (Hfl 4 ), evaporating the hafnium tetrafluoride, decomposing the hafnium tetrafluoride into hafnium and the iodine when the hafnium tetrafluoride touches the core wire of 1400-1600 C.°, crystallizing the hafnium on the core wire, and the iodine continuing to react with the rough hafnium, wherein reactions are repeated;   l. decreasing the voltage continuously with an increase of the current to maintain the temperature of the core wire at 1400-1600 C.°, and shutting off the power supply unit when the current reaches 1000-3000 A;   m. hoisting the iodizer out of the thermostatic device to a preset position for air cooling;   n. adding water into the iodizer after cooling for 24 hours; and   o. finally opening the cover of the iodizer to take out the hafnium crystal bar.   
     
     
         10 . The method for producing a hafnium crystal bar according to  claim 9 , wherein a cooling unit is started when a temperature of a saline solution exceeds 300 C.°, so that a temperature of the rough hafnium is maintained at 240-300 C.°.