JPS623767B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a reduced alkali titanate having a composition represented by the general formula M _x TiO ₂ (where M is an alkali metal and x is a positive real number). The above reduced alkali titanate has the general formula M ₂ O
(TiO ₂ ) _o (in the formula, M means the same as above, n
means an integer from 2 to 12. It is a well-known substance obtained by reducing an alkali titanate having the composition shown below (the same symbols mean the same thing). This conventionally known reduced alkali titanate, like its raw material, has a heat resistance of 1000℃ or more, has excellent heat insulation properties and chemical stability, and is used as a fire-resistant insulation material, It is expected to be used as materials, composite materials, etc. However, although conventional alkali titanates and reduced alkali titanates have the above-mentioned excellent properties, research results regarding their utilization have not necessarily been sufficiently produced. In particular, although the latter has electrical conductivity properties that the former does not have, the current situation is that research into its use has been far more neglected than that of the former alkali titanate. In recent years, with the diversification of needs, the present inventor has focused on the desire to develop composite materials with a black finish, which is extremely resistant to light reflection, and which has electrical conductivity. As a result of intensive research aimed at providing an alkali and an alkali titanate having conductivity, the present invention has been completed, which is suitable for obtaining the desired target substance. That is, in the present invention, a mixture consisting of an alkali titanate having a composition represented by the general formula M ₂ O (TiO ₂ ) _o and a carbon material is heated to a temperature of 500 to 1300 in a reducing or inert atmosphere.
It is characterized by heating at ℃. General formula M _x TiO ₂
This relates to a method for producing a reduced alkali titanate having the composition shown below. In the present invention, it is essential to heat the alkali titanate to 500 to 1300°C in a reducing or inert atmosphere in the presence of a carbon substance as a reducing agent, and under such conditions, it is generally Colored and conductive objects can be obtained. As is clear from the Examples described later, even under the conditions of the present invention, a bluish-white or blue reduced alkali titanate can be obtained. In the absence of the condition of an inert atmosphere, even if the other conditions are the same as above, only a reduced alkali metal titanate with a pale color close to white can be obtained, so the feature of the present invention is clear. Alkali titanate, which is one of the raw materials and has a composition represented by the general formula M ₂ O (TiO ₂ ) _o , has conventionally been produced by a hydrothermal synthesis method, a flux method, and a calcination method. , any of them can be used as the alkali titanate of the present invention. Carbon materials are substances that burn at 50 to 1,300 degrees Celsius and consist essentially of 80% or more by weight of carbon elements, such as graphite, charcoal, soot, coke, solid carbon such as powdered carbon, coal, bitumen, etc. These include high carbon-containing fossil components, hydrocarbon compounds, etc., and solid carbon or high carbon-containing fossil components are particularly preferred. A reducing or inert gas atmosphere is one in which a reducing gas atmosphere such as hydrogen gas, carbon monoxide gas, nitrogen gas, helium gas, carbon dioxide gas, etc., or a mixture of two or more of them, substantially contains 90% or more by volume. The atmosphere is an inert gas atmosphere, with nitrogen gas and carbon dioxide gas atmospheres being preferred. Note that when carrying out the reaction in a hydrogen gas atmosphere, it is necessary to replace the oxygen in the reaction vessel with an inert gas in advance. In the present invention, the temperature of the reaction system is raised continuously or stepwise to a predetermined temperature necessary for reduction, or the predetermined temperature is preferably approximately 700 to 700℃.
The temperature is 1200°C, and the desired predetermined temperature holding time is about 30 minutes. After heating and calcination at a predetermined temperature, the reaction system is cooled and the target product is collected. Although the cooling process does not necessarily have to be carried out in a reducing or inert gas atmosphere, it is preferable to cool the reaction system in its atmosphere. . If the cooling process is not performed in a reducing or inert gas atmosphere, the carbon material will burn and become ash, but the carbonized material that is not burned may be mixed in the object, depending on the purpose of the object. This is because it can often be used as is, and it can be removed later if it is no longer needed. The present invention described above has high industrial applicability as it can provide reduced alkali metal titanate, which is generally dark-colored and has electrical conductivity, with good reproducibility without using special equipment. It is something. Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples. Examples 1 to 10, Comparative Examples 1 to 2 10 g of potassium titanate (manufactured by Otsuka Chemical Co., Ltd., Teismo D) and 1 g of the carbon material shown in Table 1 were mixed well in a mortar. The obtained sample was placed in a boat-shaped crucible made of high-purity alumina with a capacity of 30 ml, and the crucible was placed in a tubular crucible made of high-purity alumina in which the furnace temperature was maintained at 1200°C by continuing to introduce nitrogen at a rate of 5 ml/min after replacing the crucible with nitrogen. Transfer to an electric furnace (tube inner diameter 50 mm, length 1 m) and heat for 20 minutes.
After heat treatment for a minute, the mixture was cooled to room temperature under nitrogen introduction and taken out to obtain reduced potassium titanate containing carbon substances. The properties of the obtained potassium titanate are shown in Table 1.

[Table] Examples 11 to 29 Table 2 shows the results obtained by using the same apparatus as in Example 1 while changing the mixed amounts of alkali titanate and carbon material, atmospheric gas, and firing temperature.

【table】

Claims (1)

[Claims] 1. A mixture consisting of an alkali titanate and a carbon substance having a composition represented by the general formula M ₂ O (TiO ₂ ) _o (where M is an alkali metal and n is an integer from 2 to 12) is reduced or non-reduced. Raise the temperature in an active atmosphere to 500~
A method for producing a reduced alkali titanate having a composition represented by the general formula M _x TiO ₂ (M is an alkali metal, x is a positive real number), which is characterized by heating and firing at 1300°C.