RU1812245C - Process for electrolytically producing magnesium and chlorine from chloromagnesium raw material - Google Patents

Abstract

Usage: electrolytic production of magnesium and chlorine. The purpose of the invention is to reduce losses of chlorine with sanitary gases, technical suction. Essence: molten sodium chloride and spent electrolyte of electrolysis cells fed with anhydrous carnallite are introduced into the electrolyte in a ratio of 2: 3-1 and at 680: 720 ° C. 1 tab.

Description

The invention relates to the field of non-ferrous metallurgy, in particular to the electrolytic production of magnesium and chlorine.

The aim of the invention is to reduce losses of chlorine with sanitary suction gases and increase the yield of magnesium to the flow.

The goal is achieved in that the introduction of sodium chloride and spent electrolyte into the electrolyte is carried out in the ratio (2-3): 1 and at 680-700 ° C in the form of molten salt. Said mixture is obtained by melting crystalline sodium chloride in spent electrolyte from electrolyzers fed with anhydrous carnallite.

 The essence of the proposed method is that the introduction of sodium chloride and spent electrolyte into the electrolyte is carried out in the ratio (2-3): 1 and. At 680-720 ° C in molten form. When the molten chloride mixture is charged, the boiling of the electrolyte is eliminated, and good conditions for the separation of chlorine from the electrolyte are ensured in the working electrolysis section, i.e. there is no increase in chlorine loss with sanitary suction gases when sodium and potassium chlorides are added to the electrolyte. The elimination of disturbances in the nature of the circulation of the electrolyte prevents the removal of magnesium from the collection cell into the working compartment of the electrolyzer, which reduces the loss of magnesium and, accordingly, leads to an increase in the current output of magnesium. The temperature of the molten chloride mixture to be poured must be maintained in the range of 680–720 ° C. A temperature of 10 ° C is higher than the temperature of the electrolyte in electrolyzers fed with molten magnesium chloride. At this temperature, the mixture of chlorides being poured does not violate the nature and intensity of the electrolyte circulation in the cell, i.e. no increase in losses

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magnesium and chlorine. The melting point of the mixture of the specified composition is 650 ° C, which determines the manufacturability of its use in the electrolysis process. Taking into account that the proposed mixture of chlorides is obtained by melting sodium chloride in the spent electrolyte, which is a waste of the electrolysis process, when pouring the mixture, the electrolyte composition is adjusted for two components: sodium and potassium chlorides.

The use of spent electrolyte to prepare the proposed mixture of chlorides allows to increase the degree of utilization of chloromagnesium raw materials, which will reduce the loss of chlorine from the sanitary suction gases and increase the current output of magnesium.

When the temperature of the mixture is more than 720 ° C, the circulation of the electrolyte in the collection cell of the electrolyzer is disrupted, which can lead to worsening conditions for the removal of magnesium from the working compartment and, accordingly, a decrease in the current output of magnesium. When the temperature of the mixture is less than 680 ° C, the likelihood of the entrainment of magnesium from the collection cell to the working compartment increases, which also negatively affects the electrolysis performance.

When the ratio in the mixture is less than 2: 1, the loss of magnesium chloride is not compensated, which necessitates additional loading of sodium chloride into the electrolyte in crystalline or molten form. The preparation of molten table salt is not energetically advantageous given the elevated melting point of table salt (801 ° C).

When the ratio in the mixture is more than 3: 1 of molten sodium chloride, the electrolyte is enriched with sodium chloride. This leads to an increase in the viscosity of the melt and to a deterioration of the conditions for the removal of magnesium from the working compartment into the collection cell of the electrolyzer.

PRI me R. In a salt furnace with a residual content of molten cooking

corfn and spent electrolyte in an amount of 1 ton poured 1.8 tons of spent electrolyte at 720 ° C. The table salt was periodically loaded into the furnace with the direction of the total volume of the mixture to 5 tons, and the table salt content was adjusted to a ratio of 3: 1. After preparation, the above mixture was poured into a 5-ton bucket and transported to

electrolyzer. Pouring was carried out after sampling the sludge, based on a given percentage of sodium chloride in the working electrolyte of the electrolyzer. Electrolysis was carried out at 700 ° C. After the bath was run for 24 hours, the parameters were measured and calculated: the chlorine losses with the gases of the plumbing pump were 10 kg / t, the current output of magnesium was 79.3%.

The remaining examples confirming the achievement of the goal are summarized in the table.

As follows from the table, the best performance of the cell is achieved when the ratio of the loaded mixture

5 chlorides in the ratio (2-3): 1 and a temperature of 680-720 ° C.

The advantages of the proposed technical solution in comparison with the prototype are in the reduction of losses of chlorine with sanitary exhaust gases by an average of 25 kg / t of magnesium and an increase in the yield of magnesium by 0.5-1%.

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Claims (1)

The claims A method for the electrolytic production of magnesium and chlorine from chloromagnesium raw materials, comprising periodically introducing sodium chloride and spent electrolyte into the electrolyte of electrolysis cells fed with anhydrous carnallite, characterized in that, in order to reduce chlorine losses with gases from the sanitary and technical suction and increase the yield of magnesium by current, the introduction of sodium chloride and spent electrolyte is carried out in the ratio (2-3): 1 and at a temperature of 680-720 ° C in the form of molten salt. 18122456 Table continuation