SU772480A3 - Method of producing aluminium chloride - Google Patents

Description

one

The invention relates to methods for producing aluminum chloride and can be used to produce aluminum metal by electrolyzing an aluminum chloride melt.

A method of producing aluminum chloride is known, which includes —the preliminary heating of alumina, its chlorination in the presence of carbon at 450–600 ° C. D.

There is also known a method for producing aluminum chloride by chlorinating an aluminum-containing raw material containing 50% o-alumina in the presence of a reducing agent — carbon at 450–800 0.

The disadvantage of this method is the low purity of the product, in particular, the content of non-volatile substances in the finished product reaches 16.7 wt.%.

The aim of the invention is to increase the purity of the product.

The goal is achieved 25 by the proposed method for the production of aluminum chloride by chlorination of alumina with an o6-alumina content of Mehee of 5 wt.%, With a specific surface area of at least 10 at-0

450-800 ° C In the presence of a reducing agent, for which use a mixture of alumina with carbon containing less than 5% by weight of carbon, and using alumina impregnated with carbon.

The differences of this invention is that alumina with an o.-alumina content of less than 5 wt.% With a specific surface area of at least 10 is used as an aluminum-containing raw material, and a mixture of alumina with carbon containing less than 5 wt.% Is used as a reducing agent. carbon.

This mixture is carbon-impregnated alumina.

These differences make it possible to increase the purity of the product (the content of nonvolatile substances in the final product is reduced to O, O35 wt.%). .

Example. 1. Particles of aluminum oxide containing less than 0.5 wt.% Of impurities of iron, silicon and titanium, 0.25 wt.% Of impurities of sodium (counting on Ma2-0) less than 5 wt. % ci-A ,, and less than 3% of water, with a specific surface of 100, are impregnated with carbon by thermal cracking of liquid angles in contact with alumina particles. The impregnation is carried out to the content of carbon and hydrogen in the particles of alumina, respectively 17 and 0, 18 wt.% (Of the total amount of alumina, carbon and hydrogen). The carbon dioxide particles of aluminum, free from moisture, hydrocarbon, hydrogen and oxygen, make it possible, with further chlorination, to obtain a 100% utilization of chlorine and to avoid the formation of by-products. The carbonaceous particles of alumina are continuously introduced into the chlorinator at a rate of 16 kg / h and are chlorinated at a pressure of 1-2 at a pressure of 27 kg / h in the chlorinator.

The chlorination process is carried out so as to isolate the reaction zone from moisture, oxygen, hydrogen and hydrocarbons and so that less than 5 wt.% Of chlorine is thus consumed in the reaction with them. The gaseous effluent from chlorate, containing aluminum chloride, carbon monoxide, carbon dioxide (80 wt.% Of carbon oxides), carbon and unreacted particles of coked alumina with temperature is directed to a separator, in which approximately 3 kg are separated by condensation. h product from other components of the mixture.

Example 2. Particles of coked alumina of the same composition and size as in example 1 (but with a moisture content of less than 5 wt.%), Is subjected to chlorination, as in example 1.

The chlorination temperature is maintained at a level of 575 ° C. Gaseous stream quality composition of example 1 C. temperature of 575 ° C is directed to the heat exchanger and cooled to 250 ° C and then filtered from solid and liquid particles of the stream and condensed volatile components of a mixture of sodium aluminum chloride, aluminum chloride, aluminum oxide, aluminum oxide, carbon, traces of chlorine, hydrogen chloride and phosgene. Separated from the main stream, the above mixture is returned to the chlorinator in the amount of 15% of the weight of the fresh portion of coked alumina.

High yield pure aluminum chloride is extracted from the remainder of the gaseous stream.

In the absence of recirculation of the mixture separated in the filtration stage, the yield of aluminum chloride decreases.

Example 3. Coked particles are chlorinated at elevated temperature. The resulting gaseous mixture is cooled at a temperature above the condensation temperature of aluminum chloride.

The gas stream separated from the impurities is sent to the desublimator. A desublimator contains a layer of solid particles of alu-chloride (about 41 kg), which are supported in a fluidized bed by supplying dry air. The desublimator is cooled with water at a temperature of 20 ° C, as a result of which the gaseous stream is cooled from 200 to 60 ° C, while no significant deposits are observed on the walls of the apparatus and the pipeline. The particles of chlorinated aluminum are then removed from the layer and distributed according to size.

Exhaust gas from the sublimator is sent to the filtration compartment and separated into solid particles of aluminum chloride and powder returned to the fluidized bed.

Exhaust gas contains sourdite dioxide

0 carbon, carbon monoxide, air and traces of aluminum chloride, hydrogen chloride, phosgene and carbon tetrachloride.

The resulting particles

5 aluminum chloride, at a rate of about 33 kg / h, which is removed from the apparatus, has a lobe or spherical shape and contains less than 0.3 wt.% Bound oxygen, a small amount of adsorbed carbon dioxide and phosgene (traces).

PRI me R. 4. Pure I-alumina particles with a large surface area containing less

5 0.5 wt.% Of iron, silicon and titans; Ux of compounds, 0.25% of sodium compounds (counted on. Na20), less than 3 wt.% .02 | less than 5 wt.% of water, with a specific surface area of 100 impregnated with carbon to a carbon content of 18 wt.% and an average hydrogen content of less than 0.5 wt.%

The above coked alumina particles are chlorinated in

fluidized bed of particles. Chlorine gas with a temperature is passed at a speed sufficient to maintain fluidizing conditions (n. The weight ratio of chlorine and coked alumina is maintained from 1 to 0.55. The temperature in the reaction zone due to its exothermicity is maintained at 690-740 ° C. The resulting gaseous mixture

5 cooled to 370-400 ° C. The gaseous mixture contains less than 0.3% by weight of free oxygen, less than 0%, 5% water, and water-mixed products of the reaction of guineuminium chloride.

About Cool; kdenny gaseous stream is filtered from dust, liquid particles and condensed volatile products from a mixture of sodium aluminum chloride, aluminum chloride, aluminum oxide, aluminum oxide, carbon.

Claims (2)

Formula inventions 1. The method of producing aluminum chloride by chlorination of aluminum-containing raw materials at 450-800 ° C in the presence of a reducing agent, which entails the fact that, in order to increase the purity of the product, alumina with a content of less than (aluminum oxide) is used as an aluminum-containing raw material 5 wt.%, With a solid surface of at least 10 m ² / g, and as a reducing agent use a mixture of alumina with carbon containing less than 5 wt.% Carbon. 2. The method according to claim 1, characterized in that they use carbon-impregnated alumina.