RU2186154C1 - Electrolyzer for production of magnesium and chlorine - Google Patents

Abstract

FIELD: non-ferrous metallurgy. SUBSTANCE: the electrolyzer for production of magnesium and chlorine has a housing, refractory lining forming a reservoir separated by partitions into electrolytic cells with anodes and cathodes, and a built-up cell, and a covering in the form of an arch positioned above the cells, it is provided with a chamber for feed of raw material with a sealed cover and a hatch for loading of raw material, positioned outside the cells in the lining perpendicularly to the built-up cell, communicating with it through a flow-over passage with a hydro seal, and the covering in the form of an arch is made common for the built-up and electrolytic cells and installed in a spaced relation between the covering and partitions for forming of a single gas space above the electrolytic and built-up cells. EFFECT: enhanced capacity and service life of the electrolyzer, reduced specific consumption of electric power and expenditures connected with detoxication of chlorine-containing gases. 2 cl, 2 dwg

Description

 The invention relates to the metallurgy of non-ferrous metals, in particular to devices for the electrolytic production of magnesium and chlorine from molten chlorides.

 The main factors affecting the economic efficiency of the design of the electrolyzer are its service life, current output of magnesium and specific electricity consumption. The service life of the cell depends on the design and resistance of the overlap of the cell and dividing walls between the electrolytic and precast cells. A significant part of the magnesium is lost with the sludge due to its oxidation in the collection cell. The costs of neutralizing the chlorine-containing gases of the collection cell are quite substantial.

 The development of the design of the electrolyzer, eliminating the loss of magnesium with sludge and the costs of the disposal of chlorine-containing gases, is one of the urgent problems.

 Known head refining electrolyzer (RF patent 2111286, publ. 05/20/98, BI 14), including a steel casing, refractory lining, prefabricated and electrolytic cells with installed anodes and cathodes and separated from the prefabricated cells by partitions, and the partitions are immersed in the melt and the lower edges form a gap with the upper edges of the cathodes. Through the channel, the melt enters the receiving chamber for sedimentation of solid suspensions, which is separated from the electrolytic cells by a dividing wall with transfer channels.

 The disadvantage of this design of the cell is that this cell operates only in the production line of magnesium electrolysis as a refining cell with a top input of anodes and is not suitable for individual supply of raw materials to the cell. Partitions between electrolytic and prefabricated cells separate both the electrolyte and the gas space of the cells. The costs of neutralizing the chlorine-containing gases of the prefabricated cells are saved.

 A well-known chamber for feeding magnesium electrolyzers with solid, non-dehydrated carnallite (ed. Certificate of USSR 151031, publ. BI 20 for 1962), built into the electrolyzer and equipped with vertical partitions dividing it into a series of consecutive sections and made alternately not reaching the bottom or top of the chamber . This ensures the sequential passage of carnallite through the sections from top to bottom and from bottom to top and its entry on the surface of the electrolyte in the form of a trickle.

 The disadvantage of this chamber is that this design does not completely get rid of sludge, since the cell is not sealed, and magnesium is oxidized. Saved the cost of the disposal of chlorine-containing gas electrolyzer.

 Known electrolyzer with a lower input of anodes for producing magnesium (patent 2109851, publ. BI 12 04/27/98), including a bath with lined walls, separated by a partition on the electrolytic and prefabricated compartments, closed on top with multilayer ceilings, freely laid on the supporting surface of the lining of vertical walls with the possibility of thermal expansion of free movement in the horizontal plane.

 The disadvantage of this design of the overlapping of the electrolyzer is that magnesium is oxidized in the collection cell due to incomplete sealing of the electrolysis cell, since only the electrolytic cells are hermetically closed, and when the molten raw material is loaded into the collection cell, impurities enter the electrolyzer that impair the electrolysis process. Significant costs for the disposal of chlorine-containing gases.

 The closest analogue, taken as a prototype, is an electrolyzer for producing magnesium and chlorine (patent 1739682, publ. In 1994), containing a casing, refractory lining, overlap, electrolytic cells with electrodes and prefabricated cells separated by partitions with transfer channels, moreover The lining of electrolytic cells is made with niches in which an arch-shaped overlap is installed, while the gaps between the arch and the lining are filled with granular granular material. An overlap in the form of an arch is placed only above the electrolytic cells. This design of the cell allows you to increase the concentration of chlorine in the cell and increase the life of the cell.

 The disadvantages of this design of the cell are the loss of magnesium with sludge, the use of manual labor to extract sludge, which reduces the productivity of the cell and its service life. The specific energy consumption is relatively large. Saved the cost of neutralizing the gases of the collection cell.

 The objective of the invention is the creation of a fully sealed cell, eliminating the loss of magnesium from the sludge, reducing the proportion of manual labor in the selection of sludge. The technical result due to this will lead to an increase in the productivity and service life of the electrolyzer, and the cost of neutralizing chlorine-containing gases will decrease.

 The technical result is achieved in that in the electrolytic cell for producing magnesium and chlorine, containing a casing, a refractory lining forming a container divided by partitions into electrolytic cells with anodes and cathodes and a collection cell, and an arch-shaped overlap placed above the cells is new, that it is equipped with a chamber for feeding raw materials with an airtight lid and a hatch for loading raw materials placed outside the cells in the lining perpendicular to the assembly cell communicated with it by a transfer channel with a water seal, and the overlap in the form e arches are made uniform for the precast and electrolytic cells and installed with a gap between the ceiling and partitions with the possibility of forming a single gas space above the precast and electrolytic cells.

 In addition, the transfer channel is made at the level of the upper edge of the cathodes.

 The implementation of the overlap in the form of an arch over the electrolytic and prefabricated cells allows eliminating the hydrolysis of magnesium chloride, sludge formation and oxidation of magnesium by eliminating the ingress of oxygen and moisture into the gas phase. Losses of magnesium are reduced, the current efficiency of magnesium is increased, the productivity and service life of the cell, and the specific energy consumption is reduced. All gases with a high chlorine content are supplied directly to the consumer.

 When loading raw materials into a separate chamber placed in the lining of the electrolyzer perpendicular to the collecting cell and communicated with the collecting cell by a channel with a water trap located at the level of the upper edge of the cathodes, it allows the sludge to be cleaned of solid suspensions, which reduces the flow of impurities into the combined and electrolytic cells, increases the life of the electrolyzer, reduced specific energy consumption.

 An analysis of the prior art by the applicant, including a search by patent and scientific and technical sources of information, and identification of sources containing information about analogues of the claimed invention, made it possible to establish that the applicant did not find a source characterized by features that are identical (identical) to all essential features of the claimed invention. The definition from the list of identified analogues of the prototype as the closest in the totality of the features of the analogue made it possible to establish a set of essential distinguishing features in relation to the technical result perceived by the applicant in the claimed device set forth in the claims. Therefore, the claimed invention meets the condition of "novelty."

 To verify compliance of the claimed invention with the condition "inventive step", the applicant conducted an additional search for known solutions in order to identify signs that match the distinctive features of the claimed device from the prototype. The search results showed that the claimed invention does not follow explicitly for a specialist from the prior art, since from the prior art as determined by the applicant, the effect of the transformations provided for by the essential features of the claimed invention is not revealed to achieve a technical result.

 Figure 1 and 2 shows the design of the cell with the lower input of the anodes and the input of the cathodes through the side walls of the cell.

 The cell consists of a casing 1, lining 2, two electrolytic cells 3, a prefabricated cell 4, dividing walls 5 between the prefabricated and electrolytic cells, transfer channels 6, cathodes 7, anodes 8, arched ceiling 9, with a pipe for extracting magnesium 10. Arched ceiling 9 is installed in a niche and sealed with backfill 11. The receiving chamber 13 has a transfer channel 12 connected to the collection cell 4, a hatch for loading raw materials 14, placed on the cover 15.

 Arched ceiling 9 is made of standard refractories outside the cell in a specialized area where there are conditions for high-quality installation and drying of the ceiling. After installation and drying, the electrolyzer is closed with an arched ceiling, which is installed in the niches of the side walls of the lining 2 and is covered with granular material 11, for example, calcium fluoride. The receiving chamber 13 is closed with a lid 15 and is also sealed with backfill.

 The cell operates as follows. The raw material is anhydrous carnallite with a magnesium chloride content of 48-50% in the form of a melt through the loading hatch 14 in the lid 15 is poured into the receiving chamber 13, defended and transferred through the transfer channel 12 to the collection cell by the method of communicating vessels 4. Through windows in the partition walls 5 the melt enters the electrolytic cells 3, where, under the influence of direct current, magnesium chloride decomposes and magnesium is released at the cathodes 7, and chlorine is released at the anodes 8. Magnesium is transported by electrolyte flow through transfer channels 6 to the collection cell 4, and through a pipe to extract magnesium 10 in the arched ceiling 9 it is periodically selected using a vacuum ladle and sent to the consumer. Chlorine (concentration of 90-95%) accumulates in the space between the arched ceiling 9 and the electrolyte, is continuously discharged through the pipeline and transferred to the consumer.

 Thus, the proposed design of the electrolyzer can reduce solid and eliminate gaseous waste, increase the current output of magnesium and the productivity of the electrolyzer by 1.0-1.5%, respectively, reduce the specific energy consumption, the life of the electrolyzer increases by 6-8 months.

Claims (2)

 1. An electrolytic cell for producing magnesium and chlorine, comprising a casing, a refractory lining, forming a container divided by partitions into electrolytic cells with anodes and cathodes and a collection cell, and an arch-shaped ceiling placed above the cells, characterized in that it is equipped with a power chamber raw materials with a sealed lid and a hatch for loading raw materials placed outside the cells in the lining perpendicular to the assembly cell communicated with it by a transfer channel with a water seal, and the arch-shaped overlap is the same for the assembly and electric lithium cells and installed with a gap between the ceiling and partitions with the possibility of the formation of a single gas space above the electrolytic and assembly cells.  2. The electrolyzer according to claim 1, characterized in that the transfer channel is made at the level of the upper edge of the cathodes.

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