金屬チタンの製錬と加工

抄録

Characterized in light weight, strength, and excellent heat and corrosion-resistance, metallic titanium is coming into the limelight as a structural material. The properties of the element may be summarised as being intermediate between those of aluminum and stainless steel.
Although titanium alloys containing aluminum, manganese, chromium and molybdenum as alloying elements are still on the way to development at present, products of excellent quality are being produced out of industrially pure titanium.
Production of metallic titanium in Japan in 1954 was 610 tons, only next to the United States of America. Production plan for 1956 is aimed at 5, 000 tons.
Since titanium ore is iron sand abundantly produced on the sea-coast of the North-eastern region and other parts of Japan, she will not become short of the resources in the future.
A brief description of refining and processing techniques of metallic titanium is as follows: Researches in the refining process of iron sand to extract pig iron from iron sand had been made by Dr. Iwase and many other laboratory men in Japan. It was before 1942 when the electric furnace refining process was developed to yield 60% TiO₂ slag and pig iron on an industrial basis.
Therefore, slight improvements over the conventional know-how was all that was necessary to complete production technique for TiO₂, a material to be used in the industrial method of metallic titanium known production as the Kroll Process, which had been established by Dr. Kroll and Mr. F. S. Wartman.
The technique to chlorinate TiO₂ to produce titanium tetrachloride, then to reduce it with magnesium to produce sponge titanium was accomplished in 1952 with Dr. Kroll's close supervision. Further, the technique of melting was completed with Mr. Gilbert's direct assistance. The subsequent processing techniques as forging, rolling, drawing and extrusion, are on the way to completion by the utilization of techniqnes and equipments for processing special steel and aluminum.
As pointed out in the main text, however, part of these techniques needs basic improvements. In order to find a method to substitute the Kroll Process, researches have been made on the fusion electrolysis method, the refining method of lower chloride, and the sodium reduction method, each of which is already developed to a stage of yielding a material as good in quality as one obtained by the Kroll Process. But, since these productions have not reached an industrial scale yet, they are not discussed in the main text excepting several special examples.
Discussions contained in the main text are as summarized below. Introduction about various characteristics of titanium as a structural material will ensue in the next issue.
I. Flow sheet for titanium production in Japan.
II. Mineral deposits yielding titanium.