CS231280B1 - A method for producing high purity aluminum sulfate - Google Patents

Abstract

The aim of the invention is a large-scale process for the production of high-purity aluminum sulfate, usable for example for the preparation of very pure aluminum oxide. This aim is achieved by the invention by a process in which a layer of lump or powdered aluminum is sprinkled from above with 35 to 65% sulfuric acid and an aluminum sulfate solution is removed from the bottom of the layer. The entire reaction system is under an internal gas atmosphere. The flowing solution is recirculated through the layer until the desired concentration is reached. In a steady state, a part of the flowing solution is taken outside the reaction system and fresh sulfuric acid is added. High-purity aluminum sulfate is separated from the obtained solution by crystallization.

Description

Process for producing high purity aluminum sulphate

It is an object of the present invention to provide a high-throughput process for producing high purity alumina sulphate useful, for example, for the preparation of very pure alumina.

This object is achieved by the process according to which the lump or powdered aluminum layer is sprinkled from above with 35 to 65% sulfuric acid and an aluminum sulphate solution is removed from the bottom of the layer. The entire reaction system is under an internal gas atmosphere. The effluent is recirculated through the bed until the desired concentration is reached. At steady state, some of the effluent is removed outside the reaction system and fresh sulfuric acid is added. Aluminum sulphate is separated from the solution obtained by crystallization and of high purity.

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BACKGROUND OF THE INVENTION 1. Field of the Invention

Teehnium aluminum sulphate is industrially produced mainly from aluminum hydroxide noho bauxite * In the production of pure aluminum sulphate *, which is a desired raw material for the production of pure alumina, for example. Sulfuric acid or sulfuric acid is fed to the present aluminum * The formation of aluminum sulphate results in constant agitation and heating of the reaction system * However, this process is lengthy * laborious and technologically difficult to control *

The above-mentioned disadvantages of the present invention eliminate the process of producing high purity aluminum sulphate by dissolving aluminum in sulfuric acid. This process consists in introducing, in an atmosphere of an inert gas such as nitrogen or carbon dioxide, into a layer of lumpy or powdered aluminum, above 50 ° C, sulfuric acid at a concentration of 35 to 65% and a temperature of 40 to 110 ° C from above and preferably water vapor from above, whereby the aluminum sulfate solution is removed from the bottom of the layer. The aluminum sulfate solution is returned to the aluminum layer.

the entire amount until the desired concentration of the solution is reached, or (at steady state) a portion of the solution continuously; removed and added fresh sulfuric acid to the system *

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The process according to the invention is easy to operate and allows large-scale production of high purity aluminum sulphate, i.e. sodium and potassium contents below 0.04%, silicon below 0.02 calcium below 0.01%, magnesium below 0.01%, and iron oxide below 0.0001%, an aluminum sulphate of this purity was obtained by crystallization from the solutions prepared according to the following examples of the process according to the invention;

Example 1

20 kg of aluminum wire preheated to 100 ° C are placed in a 150 mm diameter glass column. Under a carbon dioxide atmosphere, 40% sulfuric acid at 50 ° C is fed from above into a column of 20 dm total. and re-enters the top layer until the aluminum sulfate concentration in the solution reaches 30% ·

Example 2

The aluminum sulphate solution is prepared in a device consisting of a grate column at the bottom and an overflow tank. The column is filled with aluminum in the form of compressed waste and a nitrogen atmosphere is formed in the column. The aluminum layer is then sprinkled from above with 60% to 100 ° C and water vapor is introduced from the bottom of the column from the bottom of the column to the tank, where the cojffio is returned to the column until its concentration reaches 25% ·

Example 3

The aluminum sulphate solution obtained according to Example 2 is pumped from the tank to the column to which fresh sulfuric acid is fed.

Aluminum column filling is periodically replenished ·

Claims (4)

P 8 Ϊ D M t I Y T O L E Z U 231 280 Process for producing high purity aluminum sulphate by dissolving aluminum in sulfuric acid, characterized in that an acid is introduced from above into a layer of lumpy or powdered aluminum, preferably preheated to a temperature above 50 ° C, in an atmosphere of an inert gas such as nitrogen or carbon dioxide. sulfuric acid at a concentration of 35 to 65% and a temperature of 40 to 110 ° C, with the aluminum sulphate solution being removed from the bottom of the layer; Method according to claim 1, characterized in that a water spring is fed into the aluminum layer from below. Method according to claim 1 or 2, characterized in that the withdrawn aluminum sulphate solution is returned to the aluminum layer until the desired aluminum sulphate concentration in the solution is reached. Process according to claim 3, characterized in that after reaching the desired concentration of aluminum sulphate, part of the solution is withdrawn as a product outside the reaction system and the remaining part of the solution together with sulfuric acid is fed to the aluminum layer.