SU13075A1 - The method of obtaining free from iron cryolite - Google Patents

Description

The proposed method for the production of iron-free cryolite consists in obtaining an intermediate product on the a solution of chloride and guumin and chlorine iron hydrogen fluoride, which is converted into cryolite by reaction with an alkaline chloride solution in chiolnt. The process itself is carried out as follows: when heated to 60 ° C, aluminum chloride solution containing a significant amount of Ferric Chloride, with the numbering, passes hot hydrofluoric acid in a proportion of not more than 9 mol. HF at 1 mol. the resulting product, upon the addition of a hot saturated solution of an alkaline chloride, for example, salt in the ratio of 3 mol. NaCl at 1 mol. Al, fl ,, transfers: to sodium chiolate; The resulting chiolite free of iron in an acidic iron-containing mother liquor can be obtained in an easily separable form if the reaction mixture is subjected to prolonged stirring before adding the salt solution. The chiolite washed with some water is mixed with pure sodium fluoride in the ratio of 5 mol. NaF on 2 aluminum atoms and after some time the salt on the gruel is filtered; Iron-free cryolite is released from it. This technique is also used so that, from fluorine-containing solutions, for example, mother liquors, when preparing simple or complex fluorine compounds, residues of soluble fluoride compounds can be regenerated as cryolite using added chiolite. Fluorine containing mother liquors from chiolite are used to decompose clay and, after separation from undecomposed clay, chiolite is obtained again, which is then converted into cryolite. Cryolite production is also achieved by using mother liquors containing alkali metals from the preparation of complex fluoride compounds, which are added to the resulting chiolite.

Subject of a patent.

1. A method for producing iron-free cryolite from iron-containing aluminum salts, which is different

THAT - to these solutions add no more than 9 mol. TOpHcforo hydrogen and mole, alkaline myald chloride per 1 mole. in order to obtain a chiolite, which is then converted in a known manner into cryolite .., i.

2. Acceptance of the method indicated in n. 1, characterized in that the alkali metal chloride is added to the hot mixture of a solution of an aluminum salt with hydrogen fluoride only when it is not stirred thoroughly.

3. A method for carrying out the process described in claim 1, characterized in that iron-free chiolite is mixed with water and alkali fluoride in order to obtain cryolite in salt slurry.

4. Acceptance of the method referred to in Clauses J and 2, characterized in that the acidic fluorine-containing mother liquors from chiolite are used; to decompose clay to make it suitable for hyryte.

5. Acceptance of the method indicated in n. 1, characterized in that to obtain cryolite from chiolite, instead of a saturated solution of alkali fluoride, mother solutions from the preparation of simple and complex fluorine compounds containing alkali fluoride are used.