SU1691428A1 - Method of electrolytic refining of aluminium - Google Patents

Abstract

This invention relates to the electrolytic refining of aluminum in a three-layer process. The purpose of the invention is to reduce the consumption of fluoride salts and reduce labor costs. When adjusting the electrolyte with aluminum fluoride, it is introduced into the anode alloy through the filling pocket of the electrolyzer together with raw aluminum. 1 hp f-ly, 1 tab.

Description

This invention relates to non-ferrous metallurgy, in particular to methods for electrolytic refining of aluminum.

The purpose of the invention is to reduce the consumption of fluoride salts and reduce labor costs.

According to the method of electrolytic refining of aluminum, which includes periodically pouring a melt of fluoride-chloride salts into a refining electrolyzer, pouring raw metal and adjusting electrolyte with aluminum fluoride, melting fluoride-chloride salts are prepared in special electrolyzers (baths), followed by casting baths, and aluminum fluoride is fed into the anode alloy through the filling pocket of the refining electrolyzer simultaneously with the filling of the raw metal.

According to the method of electrolytic refining of aluminum, the preparation of an electrolyte is carried out in two stages in different units: the fusion of fluoride-chloride salts is carried out in baths and wines, and the addition of aluminum fluoride in a refining electrolyzer, and

aluminum fluoride is fed directly into the anode alloy through the filling pocket of the refining electrolyzer simultaneously with the filling of the raw metal, from where it passes into the electrolyte.

Compared with the known methods, the preparation of an electrolyte according to the proposed method is characterized in that supplying aluminum fluoride to the anode alloy of the refining electrolyzer simultaneously with metal casting reduces the loss of aluminum fluoride by reducing its losses into the gas phase, since the temperature of the anode alloy is 50 to 100 ° C below the electrolyte temperature in the bath. The proposed method allows individual adjustment of the electrolyte in the refining electrolyzers by the cryolite module depending on their technological state. In addition, when aluminum fluoride is supplied to the anode alloy, along with metal pouring through the casting pocket, partial refining of the raw metal occurs, which improves the quality of the final product - high-purity aluminum.

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This is the essence of the differences of the proposed technical solution.

The method is carried out as follows.

The electrolyte by the cryolite module 2.5, which is a melt of barium chloride and cryolite salts, is sent to the bath-uterus and then poured into the refining electrolyzers. Aluminum fluoride is served individually in each refining electrolyzer after pouring the main molten salt. The required amount of aluminum fluoride (to reduce the cryolite module by stoichiometry to 1.8-2.0) is fed into the anode alloy through the filling pocket of the refining electrolyzer simultaneously with the pouring of the metal. The proposed technology allows reducing the loss of aluminum fluoride in the preparation of electrolyte in the process of electrolytic refining of aluminum by 1.6 times.

PRI me R. In the electrolyzer containing 5.6 tons of electrolyte with KO. 2.5, 1 time every two days for 6 days add 100 kg of aluminum fluoride through the filling pocket (only 300 kg) together with raw aluminum, followed by KO. reduced to 1.9.

Thus, to reduce KO. by 0.1 per 1 ton of electrolyte contained in the electrolyzer, it is necessary to add 9.0 - 9.1 kg of aluminum fluoride, which is 14 - 16% more than in stoichiometry.

The loss in the conventional electrolyte preparation method is 20-25%.

With the introduction through the pouring pocket, the concentration of MD in the cathode metal decreases from 0.0100 to 0.0080%.

By a known method, the concentration of Md in the cathode metal does not change. Comparative data on the implementation of the method are given in the table.

The proposed method allows individual adjustment of the electrolyte of the refining electrolyzers depending on their technological state.

Claims (2)

1. Electrolytic aluminum refining method including anodic dissolving aluminum from an aluminum-copper alloy, cathodic reduction of aluminum, periodically pouring fluorine and chloride salts, aluminum and arsenic into the refining electrolyzer the adjustment of the electrolyte with aluminum fluoride, characterized in that, in order to reduce the consumption of fluoride salts, the adjustment of the electrolyte is carried out by feeding aluminum fluoride into the anodic alloy. 2. A method according to claim 1, characterized in that, in order to reduce labor costs, the supply of aluminum fluoride is carried out through the filling pocket of the electrolyzer together with raw aluminum.