Preparing method of low-oxygen large-dimension high-purity hafnium powder

A large-size, high-purity technology, applied in the field of preparation of high-purity hafnium materials, low oxygen, large-size high-purity hafnium powder, can solve the problems of low production efficiency, complex process, high impurity oxygen content, etc., to prevent friction spontaneous combustion, Avoid local overheating, prevent blocking effect

Inactive Publication Date: 2014-10-15
GENERAL RESEARCH INSTITUTE FOR NONFERROUS METALS BEIJNG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, these existing methods have certain limitations, or the process is too complicated, or the production efficiency is low, or the impurity oxygen content in the product is higher than 0.2wt%.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Weigh hafnium oxide with a purity of 99.9% by weight and a particle size of less than 1mm and a massive reducing agent metallic calcium with a purity of more than 98% by weight. The molar ratio of hafnium oxide to metallic calcium is 1:2. At the same time, weigh a certain mass with a purity greater than 96.0wt %, the particle size is less than 2mm molten salt CaCl 2 , And reducing agent and molten salt CaCl 2 The molar ratio is 1:1. According to the mixture of 1 / 3 mass of molten salt, hafnium oxide and metal calcium, 2 / 3 mass of molten salt is sequentially charged into the molybdenum crucible. Put the crucible into the reaction tank, close the lid and evacuate to 0.01 Pa and wash with argon. Heat to 850°C for 0.5 hours and keep at 850°C for 12 hours, protected by argon, and cool to room temperature in an argon atmosphere. The reaction product was washed 15 times with 0.2M hydrochloric acid at room temperature, and then washed once with deionized water at room temperature...

Embodiment 2

[0029] Weigh hafnium oxide with a purity of 99.9wt% and a particle size of less than 1mm and a reducing agent LiH powder with a purity of greater than 98.9wt% and a particle size of less than 1mm. The molar ratio of the hafnium oxide to the metal LiH powder is 1:5, and a certain quality of purity is also weighed More than 96.0wt%, particle size less than 2mm molten salt NaCl, and the molar ratio of reducing agent to molten salt NaCl is 1:3, according to the 1 / 3 mass of molten salt, the mixture of hafnium oxide and LiH powder, the 2 / 3 mass of molten salt The salt is sequentially charged into the niobium crucible. Put the crucible into the reaction tank, close the lid and evacuate to 0.04Pa, and wash with argon. Heat to 1300°C for 6 hours, keep at 1300°C for 10 hours, protect with argon, and cool to room temperature in an argon atmosphere. The reaction product was washed 10 times with 0.2M hydrochloric acid at 70°C, and then washed once with deionized water at 70°C. The obtained...

Embodiment 3

[0031] Weigh hafnium oxide with a purity of 99.9wt% and a particle size of less than 1mm and a reducing agent Mg powder with a purity of greater than 98.9wt% and a particle size of less than 1mm. The molar ratio of the hafnium oxide to the metal Mg powder is 1:2, and a certain quality of purity More than 96.0wt%, particle size less than 2mm molten salt MgCl 2 , And reducing agent and molten salt MgCl 2 The molar ratio is 1:3, and the molten salt of 1 / 3 mass, the mixture of hafnium oxide and metal Mg powder, and the molten salt of 2 / 3 mass are sequentially charged into the molybdenum crucible. Put the crucible into the reaction tank, close the lid and evacuate to 0.03Pa and wash with argon. Heat to 900°C for 2 hours, keep at 900°C for 5 hours, protect with argon, and cool to room temperature in an argon atmosphere. The reaction product was washed 7 times with 0.2M nitric acid at 40°C, and then washed 10 times with deionized water at room temperature. The obtained product was sie...

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Abstract

The invention relates to a preparing method of low-oxygen large-dimension high-purity hafnium powder. The purity of the low-oxygen large-dimension high-purity hafnium powder is as high as 99.99 weight percent, the oxygen content is less than 0.2 percent, and the granularity is greater than 1mu. m. A preparing process comprises the following steps that a, hafnium oxide powder, reducing agents and molten salt are contained into a crucible; b, the crucible is placed into a reaction tank, vacuum pumping is carried out after the device is sealed, then, argon gas is filled for washing, heating reduction is carried out, then, constant-temperature heat-insulation reduction is carried out, and cooling and furnace discharging are carried out after the reduction completion; c, obtained products are firstly washed by acid and are then washed by de-ionized water, then, sieving and drying are carried out, and the low-oxygen large-dimension high-purity hafnium powder can be obtained. The molten salt system adopted by the method provided by the invention has the advantages that the oxygen content in the hafnium powder can be effectively removed, meanwhile, the dimension of the hafnium powder can be controlled, the friction spontaneous combustion of the hafnium powder is prevented, and safety and controllability are realized.

Description

Technical field [0001] The invention relates to a preparation method of low-oxygen, large-size and high-purity hafnium powder, which prepares low-oxygen, large-size and high-purity hafnium materials by reducing its metal oxides by means of molten salt solution, and particularly relates to a particle size controllable and quality Controllable preparation method of high purity hafnium. Background technique [0002] Hafnium has excellent heat resistance and corrosion resistance, and has a large thermal neutron capture cross-section (115b). Pure hafnium is plastic and easy to process. It is an important material in the atomic energy industry. It can absorb thermal neutrons from nuclear reactors and control the reaction speed of the reactor. Control rods and protection devices used in atomic reactors. At the same time, because hafnium has high oxidation resistance, good thermal and electrical conductivity and low electron work function, it is used as the plasma emitter of plasma cutt...

Claims

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Application Information

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IPC IPC(8): B22F9/20
Inventor 黄永章王力军王芳江洪林张力罗远辉陈松薛红霞
Owner GENERAL RESEARCH INSTITUTE FOR NONFERROUS METALS BEIJNG
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