JPS5940767B2 - Manufacturing method of amorphous titania - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing amorphous titanium which has excellent performance as a cation exchanger, a cation adsorbent, a catalyst and catalyst carrier, a filtering agent, and the like.

Conventionally, a method for producing amorphous chikunya hydrate by hydrolyzing titanium alkoxide has been known.

The amorphous chikunya hydrate obtained by this method has a large difference in specific surface area and particle size depending on the processing conditions, and the reactivity changes markedly. Crystallization occurred and it was difficult to obtain anhydrous amorphous chikuna.

The present invention aims to provide a method for obtaining anhydrous amorphous chikunya by dehydration from chikunya hydrate.

The present invention provides crystalline phase alkali metal titanate M20-nT
A compound with a composition of t02 (where M represents Na, Rb or Cs, and n is 1 to 6) is treated with an acid aqueous solution to extract the M20 component, and TiO2.n H2
Chikunya hydrate with a composition of 0 and the obtained hydrate with a composition of 2
The method involves dehydration treatment at a temperature of 00°C or higher and lower than the anatase crystallization temperature.

The crystalline alkali metal titanate used in the method of the present invention is, for example, a mixture of powders of titanium oxide and an alkali component with M2
()nTi02 (M and n are the same as above, the same applies hereafter) is heated at a temperature lower than its melting temperature, and the two do not melt but undergo a solid phase reaction. Obtained as alkali metal titanate in the form of crystalline particles.

It can also be obtained by heating and reacting an amorphous alkali metal titanate at a temperature lower than its melting temperature.

However, not only these methods but also those produced by other methods can be used.

Any type of titanium oxide may be used as the titanium component, but it is desirable that it easily reacts with alkali IJ and urine components.

Therefore, the particle size is fine and the specific surface area is large, preferably 50
It is preferable to have a reactive activity at a particle size of 0 to 0.1 rrl/9.

In this respect, the anatase type is better.

Examples of the alkaline component include KOH and NaOH.

RbOH, CsOH, 2COs, Na2CO3
, Rb2COs.

C3C03, KHCO3, NaHCO3, RbHCO3
゜C3HC03, 20. Na2O, Rb2O, C52
An alkali metal oxide such as 0 or an alkali metal compound which produces an oxide upon heating is used.

The crystalline alkali metal titanate obtained from the mixture of these raw materials by the above method is treated with an aqueous solution of an acid such as a mineral acid or an organic acid to extract the M20 component.

The extractant for these M20 components must not dissolve alkali metal titanate.

For example, it dissolves in concentrated sulfuric acid, so care must be taken.

Hydrochloric acid aqueous solution is preferred because it is easy to extract and does not dissolve.

This extraction may be performed by heating an aqueous acid solution at a temperature below its boiling point, or by performing operations such as stirring and circulation.

If the extraction of the M and 0 components is carried out too rapidly, the M20 component of only the surface portion will be extracted and the M20 component of the core portion will remain, so it is preferable to carry out the extraction over a period of time.

However, in some cases, a certain amount of M20 component may remain to increase the cation exchange capacity.

Chikunya hydrate with a TiO2/nH2O composition that has been subjected to extraction treatment for the M20 component retains the original alkali metal titanate skeleton structure, and the alkali metal ions are H+ or H3
It is a crystalline substance with a structure in which 0+ ions are substituted.

and has swelling and dehydration properties, and H+ or H30+
It has ion exchange and ion adsorption properties to replace ions with other complex ions.

Anhydrous amorphous chikunya is obtained by heating the obtained crystalline chikunya hydrate at a temperature lower than 600° C., which is lower than the temperature at which anatase-type titanium crystallizes at 200° C. or more.

This amorphous chikunya has excellent ion adsorption properties for polyvalent cations and the like.

It can also be used as a gas adsorption purifier and filter.

Example TiO2 (anatase type) 0.01μm and 2CO30
, 01 μm were mixed well at a molar ratio of 4:1.

The mixture 239 was filled into a 100 yd platinum crucible, and heated and reacted at 800° C. for 10 hours using an electric furnace.

This reaction product has particles of 0.05 μm to 0.1 μm and a specific surface area of 1 to 0.1 μm. It was about In/g.

This product was identified by X-ray diffraction, and all 2Ti4
0. It was phase.

This was immersed in the aqueous solution at a ratio of 10 g to 100 ml of 1N-HCl aqueous solution, and stirred for about 1 hour.
0 component was extracted.

This was washed with water and air-dried to obtain a crystalline chikunya hydrate.

The obtained hydrate was heated and dehydrated at 500°C to obtain amorphous chikunya.

This amorphous chikunya has no hygroscopicity or water absorption, and does not exhibit swelling or dehydration properties.

Claims (1)

[Claims] 1. An alkali metal titanate having a crystalline phase represented by the general formula M20 ・n T t O2 (where M represents Na, K, Rb, or Cs, and n is 1 to 6) is dissolved in an acid aqueous solution. to extract the M20 component, TiO2・nH2O (however, n
is a chikunya hydrate having the composition of 1 to 6), and the obtained chikunya hydrate is dehydrated at a temperature of 200°C or higher and lower than the anatase crystallization temperature. .