JPS58110628A - Manufacture of metallic zirconium - Google Patents

Abstract

PURPOSE:To manufacture metallic Zr contg. uniformly added oxygen and carbon at high contents by feeding CO2 or CO onto metallic Mg together with refined ZrCl4 in a stage for smelting metallic Zr by the Kroll process. CONSTITUTION:In a stage for smelting metallic Zr by the Kroll processm gaseout CO2 or CO is fed onto metallic Mg together with refined ZrCl4 to add carbon and oxygen to produced metallic Zr. Metallic Zr reacts with CO2 or CO at a high temp., formong ZrC and ZrO2. By making use of the fact, the amount of C and O in spongy metallic Zr are increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing spongy metal zirconium by adding carbon and oxygen to spongy metal zirconium.

To industrially produce spongy metallic zirconium,
Generally, a method called the crawl method is used.

In the four-four method, solid or liquid metal magnesium is first charged into a reduction reaction vessel, and purified zirconium tetrachloride vapor is introduced under an inert gas atmosphere.
In this method, a reduction reaction is carried out at high temperature according to the following reaction formula to produce spongy metallic zirconium.

ZrC1a + 2 Mg x Zr + 2 MgO
Zirconium produced in this way has a small thermal neutron absorption cross section, so it has attracted attention as a nuclear reactor material. It is used in alloys called Zircaloy-2 and Zircaloy-4, in which niobium is added in small amounts, and in zirconium-niobium alloys, in which niobium is added.

Since these alloys are also exposed to high-temperature, high-pressure steam inside a nuclear reactor, further improvements have been desired in terms of heat resistance, corrosion resistance, and high strength.

To this end, it has been found that increasing the content of carbon and oxygen in zirconium significantly improves these properties.

As a method to increase the content of carbon and oxygen.

First, in an attempt to increase the carbon content, zirconium carbide and oil-covered return material were added in the raw material preparation stage before vacuum melting, and in an attempt to increase the oxygen content, zirconium oxide was added. However, the sufficient height K
It was not possible to increase the carbon and oxygen content up to

In particular, when zirconium oxide was added, since the melting point of this zirconium oxide was as high as 2715° C., there was a problem that it could not be completely dissolved during melting, causing segregation.

In view of this point, the present inventors conducted a process of smelting metal zirconium using the Kroll method.

Carbon dioxide gas or carbon monoxide is supplied together with purified zirconium tetrachloride onto metal magnesium.

We have developed a method for producing metallic zirconium by adding carbon and oxygen to the produced metallic zirconium.

This method utilizes the fact that metallic zirconium reacts with carbon dioxide gas or carbon monoxide at high temperatures according to a linear equation, forming zirconium carbide and zirconium oxide.
Carbon and oxygen are increased during the manufacturing process of spongy metal zirconium.

2Zr + Cow → ZrC + ZrO 5 Zr + 200 → 2ZrC + ZrO pipe This allows oxygen and carbon to be added uniformly and at a high content into the zirconium sponge, making it easy to obtain metallic zirconium and zirconium alloys that are extremely effective as nuclear reactor structural materials. Now I can do it.

Next, an example will be described.

Example 1 During the reduction reaction process by Kroll method, zirconium tetrachloride vapor was supplied at 60 k/hr, and carbon dioxide gas was added to it at 1
The mixture was fed at a reaction temperature of 800° C. while stirring at a rate of 0 Llhr. The reaction is exothermic.

Take out the reaction product of about 1500 m and vacuum width of about 100 m
By-product magnesium chloride is removed at 0°C. The oxygen and carbon analysis results of the spongy metal zirconium thus obtained were as follows.

Oxygen 1450 ppm Carbon
180 ppm Example 2 During the reduction reaction process using the Kroll method, zirconium tetrachloride vapor was supplied at a rate of 60 kg/hr, and -carbon oxide was mixed and supplied at a rate of 12 Llhr. Approximately 15001
Take out the reaction product of
By-product magnesium chloride was removed at 0°C.

The analysis results of oxygen and carbon in the nine spongy metal zirconium obtained were as follows.

Oxygen: 1 2 5 7 ppm Carbon: 290 ppm Comparatively, the contents of oxygen and carbon in the sponge metal zirconium obtained by the conventional Kroll method are 9001, respectively)
P! 1 and 50 ppm, 9 The amount of oxygen and carbon in the sponge-like metal zirconium obtained by the method of the present invention was slightly less than twice as much as oxygen and 6 to 9 times as much as carbon, indicating that it was contained extremely effectively. I understand.

Claims (1)

[Claims] A method for producing metallic zirconium in which carbon dioxide or carbon monoxide is supplied together with purified zirconium tetrachloride onto metallic magnesium in the process of smelting metallic zirconium using the Kroll method, and carbon and oxygen are added to the produced metallic zirconium.