SU1119982A1 - Method of obtaining lithium titanium - Google Patents

Abstract

METHOD FOR OBTAINING LITHIUM TITANATE of composition Li, Tij.O, where O i 0.3, annealing the briquetted mixture of oxygen-containing lithium compound and titanium oxides

Description

WITH

 00 th

one

The invention relates to inorganic chemistry, namely the synthesis of oxide compounds containing lithium and titanium, and can be used in the preparation of superconducting materials.

A known method for producing the oxide compound HTHO is by reacting a mixture of oxides LijO and Ti, 0, 1.

The process is conducted at 1000 ° C in argon. The preparation of compounds of the composition, Ti.04 where i 0.3, containing titanium in oxidation state (IH), is impossible by this method.

The closest to the proposed effect achieved is a method for producing lithium titanate

Li ,,, Oi X i 0, by heating a mixture of an oxygen-containing lithium salt (for example, LijCOj) with titanium dioxide TiO, compressed at a pressure of J800 kg / cm, in an oxygen atmosphere. The firing temperature is 740-750s. Then, the resulting composition is ground with the addition of the required amount of oxide TijOj, pressed into tablets at a pressure of 7200-14400 kg / cm and pulled out in a stream of inert gas at 750800 ° C for 12-24 h 2

The disadvantages of the method include the duration of the preparation process (only the second stage lasts 12-24 hours, the duration of its first stage is even longer due to the low reactivity of titanium dioxide in reactions with salts), the need to use high pressing pressures, and the low purity of the final product and a violation of the required stoichiometric ratio of the components. For example, in the synthesis of titanate with 0.05x and 0.15 of the required phase, less than 40% is formed, and the phase and chemical composition of the resulting impurities is not established.

The purpose of the invention is to increase the purity of the final product and accelerate the process.

This goal is achieved by the fact that according to the method of producing lithium titanate of composition Li + jTij O where O 6 X $ 0.3, annealing the briquetted mixture of oxygen-containing lithium compound and oxides of titanium (III) and (IV) mixture and porous metal

Plastic titanium is placed in different sections of a two-section ampoule, before annealing, the system is evacuated to mm Hg, the section containing titanium is heated at 780820 0 for 3-5 minutes and is soldered.

A mixture of lithium oxide LijO and titanium oxides TijO, and TiOj of the corresponding stoichiometric composition is collected, briquetted at a pressure of 1500–2000 kg / cm, and the sample obtained is placed in an ampule divided into two sections

and from which there is a sample, and in another a porous titanium metal. After evacuating air from the ampoule to -10 mm Hg. it is sealed. Section containing titanium,

2JJ is heated to 780-820s and held for 3-5 minutes, after which this part is sealed off. The evacuated ampoule with the sample is heated to 750–800 ° C for 10–15 h. The product obtained is analyzed by X-ray phase and chemical methods.

Processing the reaction space using porous metallic titanium prevents the partial oxidation of Ti (III) - - Ti (IV) and the violation of the stoichiometry of the mixture.

With a residual pressure of more than Hg. and temperature below 780 ° C

5 titanium is passivated by forming oxide TiOj; As a result, the residual oxygen in the ampoule oxidizes Ti (III), thereby violating the stoichiometry of the mixture.

With a residual pressure of less than

10 mm Hg and the temperature is higher than the oxygen pressure in the ampoule after heating and delivery for 3-5 minutes less than the equilibrium over

TiOj oxide, as a result of which, in the process of obtaining, part of the oxygen passes from the sample into the reaction space, thus violating the required stoichiometric ratio of KOhmoHeHfoB.

A run time of 3-5 minutes is optimal to ensure the synthesis of a single-phase product.

Example 1. A mixture containing 0.2990 g, 1.5980 g of TiO, and 1.4380 g of TijOj is carefully ground, briquetted at a pressure of 1500 kg / cm and placed in a quartz glass.

J1

ampoule divided into two sections. A porous titanium metal is placed in the second section of the ampoule. The ampoule is pumped out to tO mm Hg. Then they are sealed and the part containing titanium is heated to and held for 5 minutes, then it is sealed off.

The evacuated vial with the sample is heated for 15 hours at. The resulting product is cooled in the vial. X-ray phase analysis shows the presence of a single phase LiTijOi.

The composition of the product, wt.%: Li4,10

, 65

, 77

O38.90

With accuracy of analysis, this corresponds to the theoretical content of elements in the LiTij04 compound. Example 2. A mixture containing 0.3887 g of Li, O, 0.1438 g of TiOj and 2.5568 g of TijOj is carefully triturated at a pressure of 2000 kg / cm, and the resulting sample is placed in a quartz ampule divided into two sections. A porous titanium metal is placed in the second section of the ampoule. The ampoule is pumped out to 10 mm Hg, sealed. Section containing titanium, on 9824

Warm up and hold for 3 minutes, then it is sealed from the ampoule section containing the sample. The evacuated sample vial is heated at 800 ° C for 10 hours. The resulting product is cooled in a vial. X-ray phase analysis shows the presence of a single phase M. 4 Composition of the product, wt.%: Li5.89

Ti 49.71 Ti 3.15 O41.82

This With the accuracy of the analysis error corresponds to the theoretical content of elements in the compound Lil. Ti.T Q.

The use of the proposed method allows to simplify the process due to the elimination of secondary pressing at high pressures (7200-14400 kg / cm in a known method), to intensify by conducting it in one stage (reduction time to 10-15 hours). In addition, the method allows to obtain a pure product without impurities, which is confirmed by X-ray phase and chemical analysis data.

Claims (1)

METHOD FOR PRODUCING LITHIUM TITANATE Composition Li ^ ,,, Ti _g . _x 0 ₄ , where 0 6 x <0.3, annealing the briquetted mixture of an oxygen-containing lithium compound and titanium oxides (III) and (IV), characterized in that, in order to increase the purity of the product and speed up the process, the briquetted mixture and porous metal titanium they are placed in different sections of a two-section ampoule, before annealing, the system is vacuumized to 10 * 10 * 2 mm Hg, the section containing titanium is heated at 780-820 ° C for 3-5 minutes and it is desoldered. CO with © 00 y