CN1074391C

CN1074391C - fibrous nanometer potasium titanate and its preparing method

Info

Publication number: CN1074391C
Application number: CN97106995A
Authority: CN
Inventors: 汪国忠; 田兴友; 张立德
Original assignee: INST OF SOLID PHYSICS CHINESE
Current assignee: INST OF SOLID PHYSICS CHINESE; Institute of Solid State Physics ISSP of CAS
Priority date: 1997-06-12
Filing date: 1997-06-12
Publication date: 2001-11-07
Anticipated expiration: 2017-06-12
Also published as: CN1202462A

Abstract

The present invention discloses a preparation method of fibrous nanometer potassium titanate by a chemical coprecipitation method. The present invention comprises the following steps: firstly, ilmenite is soaked in concentrated sulfuric acid to generate titanium oxide sulfate; the titanium oxide sulfate is hydrolyzed to generate metatitanic acid; secondly, the generated metatitanic acid is dissolved by hydrogen peroxide and ammonia water to produce a metatitanic acid solution; finally, a potassium hydroxide solution is dropped in the metatitanic acid solution to generate a precipitate, and the precipitate is calcined and is prepared fibrous nanometer potassium titanate with the fiber length of 30 to 300 nm by coprecipitation synthesis. The prepared fibrous nanometer potassium titanate by the method of the present invention can be regulated by the calcination temperature and the concentration of potassium hydroxide solution. The present invention has the advantages of simple technology, cheap and easily acquired raw materials, high purity and uniform fiber of the prepared product and wide application prospect.

Description

Fibrous nano potassium titanate and preparation method thereof

The invention relates to fibrous nano potassium titanate and a preparation method thereof.

Whiskers, which are high-strength single crystal fibers having a theoretical strength close to that of whiskers, have attracted attention of us scientists since 1948, and some researchers have produced metal and ceramic whiskers. There are several ways to prepare potassium titanate fibers: there are a sintering method, a melting method, a hydrothermal method and a flux method,however, the preparation of fibrous potassium titanate by these methods has some disadvantages. The crystallinity of the product prepared by the sintering method is not good; the single crystal prepared by the melting method has low yield and high requirement on reaction temperature; the hydrothermal method is synthesized under high pressure, so that the method has certain danger and high cost; the flux method is KCL-KF, K₂O-B₂O₃，K₂O-WO₃(MoO₃) And the cost is high because the solvent is volatile, highly corrosive and slightly soluble, and different solvents are selected according to the use purpose. In summary, most of the raw materials used in the prior art methods for preparing fibrous potassium titanate are K₂CO₃And TiO₂And all have some disadvantages.

Until now, no fibrous nano potassium titanate product exists, and no preparation method is disclosed.

The invention aims to provide the fibrous nano potassium titanate which is prepared by a chemical coprecipitation method and has good uniformity and low cost.

In order to achieve the purpose, the chemical coprecipitation preparation method comprises the following steps: soaking ilmenite in a sulfuric acid solution, wherein the mass ratio of sulfuric acid to ilmenite is at least 1.3 times, generating titanyl sulfate, hydrolyzing titanyl sulfate to generate metatitanic acid, dissolving metatitanic acid into a solution by using hydrogen peroxide and ammonia water under the ice bath condition, wherein the molar ratio of the metatitanic acid to the hydrogen peroxide to the ammonia water is 1: 16: 7, finally dripping potassium hydroxide into the solution of metatitanic acid to obtain a precipitate, calcining the precipitate at 300-1000 ℃ for more than 1 hour, and coprecipitating to synthesize fibrous nano potassium titanate, wherein the fiber length is 30-300 nm.

During preparation, ilmenite is ground into powder with the granularity of 200-500 meshes, the concentration range of sulfuric acid is 0.05-5 mol/l, hydrogen peroxide is an analytically pure commercial product, the concentration range of potassium hydroxide is 1-6 mol/l, and ammonia water is an analytically pure commercial product.

The chemical reaction formula of the method is as follows:

(calcination)

The fibrous nanometer potassium titanate with different lengths can be prepared by the difference of the final calcining temperature and the potassium hydroxide concentration.

The invention has the advantages that: adopts cheap and easily available ilmenite as a raw material, and has simple preparation process and simple equipment. The fibrous nano potassium titanate prepared by the method has high purity, uniform fiber and controllable length. Can be widely applied to carriers and adsorptive materials of heat insulation, wear resistance and catalysts.

The length control of the present invention will be further described with reference to the following examples.

Example (b):

1. the method comprises the following steps: firstly grinding 304g ilmenite into 400-mesh powder, then heating to 70-80 ℃ under stirring, dropwise adding 2000ml of 1mol/l sulfuric acid to dissolve ilmenite into titanyl sulfate, and washing with deionized water until there is no SO in titanyl sulfate₄ ^2-And Fe²⁺60ml of deionized water was added thereto, hydrolyzed to metatitanic acid, and washed with H₂TiO₃SO in (1)₄ ^2-And (4) carrying out ion filtration to obtain a precipitate, and then drying at 105 ℃ for 4 hours to obtain a pure dried metatitanic acid.

Step two: weighing 60g of metatitanic acid, adding 1000ml of hydrogen peroxide and 300ml of strong ammonia water under the conditions of ice bath and stirring to obtain an orange solution, and dissolving 70g of potassium hydroxide in the orange solutionAdding potassium hydroxide solution into 1000ml water while stirring to obtain yellow precipitate, filtering, and washing until no K exists⁺Thus, the yellow precipitate was dried in an oven at 80 ℃ for 2 hours to obtain potassium titanate.

Step three: and calcining the potassium titanate yellow precipitate obtained in the last step at 500 ℃ for 1 hour to obtain fibrous nano potassium titanate, wherein the fiber length is 50-60 nm, and the fibrous nano potassium titanate is white powder.

2. Step one, step two as in example 1, prepare yellow potassium titanate.

And step three, calcining the prepared yellow potassium titanate yellow precipitate at 700 ℃ for 1 hour to obtain fibrous nano potassium titanate, wherein the fiber length is 90-110 nm.

Claims

1. A fibrous nano potassium titanate, which is characterized in that: molecular formula is K₂TiO₃The fiber is fibrous, and the fiber length is 30 to 300 nanometers.

2. The preparation method of the fibrous nano potassium titanate is characterized by comprising the following steps of:

(1) mixing sulfuric acid with ilmenite, dissolving to obtain titanyl sulfate, wherein the mass ratio of the sulfuric acid to the ilmenite is more than or equal to 1.3 times,

(2) hydrolyzing titanyl sulfate into metatitanic acid,

(3) dissolving metatitanic acid, hydrogen peroxide and ammonia water into a solution under the ice bath condition, wherein the molar ratio of metatitanic acid to hydrogen peroxide to ammonia water is 1: 16: 7,

(4) dripping potassium hydroxide solution into metatitanic acid solution to obtain precipitate,

(5) heating the precipitate at 300-1000 deg.C for more than 1 hr.

3. The method according to claim 2, wherein the concentration of sulfuric acid is 0.05 to 5 mol/l.

4. A process according to claim 2, characterized in that the ilmenite has a particle size of 200 to 500 mesh.

5. The method of claim 2, wherein both the hydrogen peroxide and the ammonia are analytically pure.

6. The method according to claim 2, wherein the concentration of the potassium hydroxide solution is 1 to 6 mol/l.