RU2754213C1 - Method for obtaining anhydrous carnallite and processing line for implementation thereof - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: inventions relate to obtaining anhydrous carnallite. Solid raw materials are loaded into a melting chamber and melted resulting in a melt. The melt is supplied into a chlorination chamber with tuyeres for chlorination with chlorine-containing gas. Anhydrous carnallite is then settled and drained. Anode chlorine gas and dried air are supplied into the melt directly into the tuyeres of the chlorination chamber under the pressure of 0.4 to 1 atm at a volume ratio of anode chlorine gas to dried air of (0.1 to 1.0):1. Anode chlorine gas and dried air supply is controlled by valves. The processing line includes a unit for loading solid raw materials, a melting chamber, a chlorination chamber with tuyeres, a settling chamber, an anode chlorine gas supply line, an air supply line, an exhaust gas discharge line for gas cleaning, an anhydrous carnallite discharge line, an air drying unit for obtaining dry air located on the air supply line, a dry air supply line connected on one side with the air drying unit and on the other side with the dry air supply line and the anode chlorine gas supply line connected directly with the chlorination chamber tuyeres. Valves for controlling dried air and anode chlorine gas supply are installed on the dried air supply line and the anode chlorine gas supply line. A check valve is therein installed on the anode chlorine gas supply line.

EFFECT: inventions allow reducing chlorine consumption for obtaining anhydrous carnallite, increasing the degree of chlorine use, reducing the amount of sludge and reduce chlorine emissions on gas purification facilities.

2 cl, 1 dwg, 3 ex

Description

The group of inventions relates to non-ferrous metallurgy, namely to the metallurgy of magnesium, in particular to the production of anhydrous carnallite, which is a raw material for the electrolytic production of magnesium.

The production of anhydrous carnallite is carried out in two stages: the first - in rotary kilns or fluidized bed furnaces, the second - in electric furnaces of the SKN type or in chlorinators to obtain anhydrous carnallite.

A known method of producing anhydrous carnallite (ed. Certificate of the USSR No. 399574, publ. 03.10.1973, bulletin No. 39), including loading solid raw materials at the stage of melting into a space heated by electrodes. From the melting stage, the melt enters the chlorination stage, where the melt is treated with chlorine, then the melt flows to the settling stage, from where the upper melt layer (anhydrous carnallite) is sent to electrolysis, and the lower melt layer with a magnesium oxide content of 3 to 20% is returned to the chlorination stage ...

The disadvantage of this method for producing anhydrous carnallite is the low degree of chlorination of raw materials with chlorine, which leads to the formation of a large amount of sludge.

A known method of producing anhydrous carnallite and a technological line for its implementation (book. Electrolytic production of magnesium. - Strelets H.L., M .: Metallurgy. - 1972. - S. 139-151). The method consists of combined processes: melting and partial dehydration of carnallite, chlorination of magnesium oxide and residual water, and purification from harmful impurities. Dehydrated carnallite from rotary kilns is fed into bunkers by means of in-house transport, and from them, by means of a feeder screw, into an electric furnace or chlorinator, where it is melted and finally dehydrated. A bunker with a screw for loading ground petroleum coke is installed above the chlorinator. In the chlorinator smelter, along with the melting of carnallite at a temperature of 500-550 ° C, the bulk of the water is removed. In chlorinating chambers, simultaneously with heating the melt to 750-800 ° C, magnesium oxide is chlorinated with anodic chlorine gas in the presence of petroleum coke. The resulting melt of anhydrous carnallite contains up to 1% magnesium oxide and up to 0.12% petroleum coke. The resulting anhydrous carnallite is defended in a mixer from sludge and coal foam, and then poured from the mixer into ladles and transported to the electrolysis workshop.

The disadvantage of this method of obtaining anhydrous carnallite and the technological line are significant losses of magnesium chloride with sludge (~ 8% of the amount of feedstock). In addition, the low use of chlorine (no more than 10-15%) complicates the purification of gases from the chlorinator, and reduces the technical and economic indicators of the process as a whole.

A known method of producing anhydrous carnallite (Art. Reducing the loss of magnesium and chlorine when obtaining anhydrous carnallite. - Saburov L.N., Teterin V.V., Mikhailov EF, Pensky A.V. - J. Nonferrous metals, 1985. - No. 8, pp. 82-84), in which molten carnallite is dehydrated in an atmosphere of hydrogen chloride. Preliminary hydrogen chloride was obtained by oxidation of natural gas in anodic chlorine. Dehydrated carnallite from an industrial fluidized bed furnace with a composition of ~ 1.8 wt. % magnesium oxide and 2.5 wt. % water at a temperature of 500-560 ° C was melted while processing with hydrogen chloride. The installation for melting carnallite in an atmosphere of hydrogen chloride contains a shaft into which hydrogen chloride is fed from the bottom to the top through the tuyeres, dehydrated carnallite is continuously fed through the loading device from above, and the melt is poured through the drain hole. The melting unit is heated using electrodes.

The disadvantage of this method for producing anhydrous carnallite is that hydrogen chloride is obtained in a separate apparatus and additional costs are required for heating the melt and obtaining hydrogen chloride.

A known method of producing anhydrous carnallite and a technological line for its implementation (Art. Optimization of the use of chlorine during dehydration for the carnallite scheme of magnesium production. " Vokhmyanina OV - J. Non-ferrous metals, 2006. - No. 9, pp. 79-82). The method includes feeding raw materials into a multi-chamber fluidized bed furnace, the first stage of dehydration by sequential movement of raw materials through a series of horizontal furnace chambers and feeding into the furnace chamber flue gases formed by burning a mixture of natural gas and chlorine-containing gases in the furnace furnace, the second stage of dehydration in a chlorinator to obtain anhydrous carnallite for electrolytic production of magnesium and chlorine. For dehydration of carnallite raw materials in fluidized bed furnaces and chlorinators, anode chlorine gas from the process of electrolytic production of magnesium and chlorine with a chlorine content of 75-80% of the mass is used. At the second stage of dehydration, it is proposed to supply chlorinated air mixture with a chlorine content of 40% to the chlorinators. The technological line for the production of anhydrous carnallite includes a fluidized bed furnace with furnaces, a chlorinator with tuyeres, a chlorine supply line to the furnaces of the fluidized bed furnace and to the chlorinator tuyeres. To reduce the amount of chlorine used in the second stage of dehydration in the chlorinator, a scheme for diluting the anode chlorine gas with dried air was installed. Dry air supply line for chlorine dilution, connected to a chlorine dilution unit, which is installed on the chlorinator lance. The exhaust gas line from the chlorinator is connected to the gas cleaning system.

The disadvantage of this method and the technological line is that the presence of oxygen in the chlorine-air mixture leads to the formation of sludge in the chlorinator, since at high temperatures magnesium chloride interacts with atmospheric oxygen by the reaction:

This leads to losses of magnesium chloride and the formation of a large amount of sludge. In addition, a decrease in the chlorine content in the chlorine-air mixture to less than 40% causes frequent overgrowth of the chlorinator tuyeres, and the existing chlorinator design does not provide a stable operating mode.

There is a method and a technological line for dehydration of carnallite raw materials for the production of magnesium (RF patent No. 79883, publ. 20.01.2009, bulletin No. 2), including dehydration of chlorine-magnesium raw materials in a fluidized bed furnace by feeding flue gases into the bed. Dehydrated carnallite is obtained with a content of 4.5% water and 1.3% magnesium oxide. Waste gases together with dust are sent to cyclones. The dehydrated carnallite obtained in the fluidized bed furnace is fed to the second stage of dehydration - where, first, the raw material is melted in a chlorinator smelter at a temperature of 520 ° C, then chlorinated in a chlorinating chamber to obtain anhydrous carnallite. In chlorinating chambers, the melt is heated to 820 ° C, treated with a mixture of anodic chlorine gas and nitrogen supplied through a chlorine dilution unit and a tuyere. Anode chlorine gas of composition,% vol .: Cl ₂ - 81.0, KCl - 0.62, CO - 0.11, CO ₂ - 1.77, O ₂ - 4.99, N ₂ - 11.28, H ₂ O - 0.10, Ar - 0.13, is obtained in the process of electrolysis of anhydrous carnallite in electrolysers to obtain magnesium. Nitrogen is obtained in an air separation unit, an oxygen station is used as a unit. Gaseous nitrogen is supplied in an amount of 180 mm ³ / hour through the nitrogen supply line with a pump. The amount of nitrogen supplied is adjusted with a control valve. The chlorine dilution unit is made in the form of a tee, which is connected on one side with a nitrogen supply line, and on the other with a chlorine supply line and with chlorinator tuyeres. The dilution scheme includes sensors and instruments for measuring the flow rates and pressures of chlorine and nitrogen. The resulting anhydrous melt is defended in a mixer in order to remove solid inclusions and a ready-made anhydrous carnallite is obtained, wt. %: MgCl ₂ - 49.83, MgO - 0.50, H ₂ O - 0.01, KCl - 38.95, NaCl - 10.71, which is sent to electrolysis to obtain magnesium and chlorine. And the mixer sludge is sent to the waste landfill.

The disadvantage of this method and the technological line is that gaseous nitrogen is obtained in a separate apparatus and additional costs are required for the installation and operation of the installation and nitrogen supply.

There is a known method for obtaining anhydrous carnallite (USSR author's certificate No. 603706, publ. 04/25/1978, bulletin 15) by the number of common features taken as the closest prototype analogue and including loading carnallite, dehydrated in a fluidized bed furnace, into a chlorinator melter, melting at 550 ° C, overheating to 880 ° C, chlorination of magnesium oxide with a chlorine-air mixture and settling the formed chlorine-magnesium melt from solid particles. At the same time, as the magnesium oxide in the chlorinated melt decreases, the chlorine concentration in the chlorine-air mixture is reduced from 70 to 20%.

The disadvantage of this method for producing anhydrous carnallite is the complexity of the technology, which consists in the fact that it is necessary to constantly monitor the composition of anhydrous carnallite, as well as to periodically carry out the process, which reduces the productivity of the chlorinator.

Known technological line for the production of anhydrous carnallite (USSR author's certificate No. 603706, publ. 04/25/1978, bul. 15) by the number of common features taken as the closest prototype analogue and including a loading unit for carnallite dehydrated in a fluidized bed furnace, a melter where melting of salts at 550 ° С, chlorination chamber, where molten carnallite enters, and heats up to 880 ° С. In the initial period of chlorination, a chlorine-air mixture is supplied to the lower zone of the chlorination chamber through the tuyeres in an amount of 100 m ³ / h. The chlorine content in the mixture is 70%. As the concentration of magnesium oxide in the melt decreases, the chlorine consumption is reduced, and at the same time, air is supplied to the pipeline through which the chlorine-air mixture is supplied so that the total gas volume is 100 m ³ / h. The decrease in the concentration of chlorine in the mixture is 10% for every 0.5% decrease in the content of magnesium oxide in the melt. At the end of chlorination, when the magnesium oxide content in the melt decreases to 0.5%, the chlorine concentration in the chlorine-air mixture is 2.5%. The rate of decrease in the chlorine content in the chlorine-air mixture is regulated automatically according to a special program drawn up in relation to a specific design of the chlorinator and its maintenance regime, as well as the composition of carnallite dehydrated at the first stage. For this purpose, the change in the content of magnesium oxide in the melt is determined analytically. Additionally, the chlorine content in the chlorinator exhaust gases is analyzed. The finished melt with a content of 0.5% magnesium oxide enters the mixer, where it settles from sludge and coal foam.

The disadvantage of this technological line for obtaining anhydrous carnallite is the complexity of the technology, which consists in the fact that it is necessary to constantly monitor the composition of anhydrous carnallite, as well as to periodically conduct the process, which reduces the productivity of the chlorinator.

The technical result is aimed at eliminating the shortcomings of the prototype and allows:

- to reduce the consumption of chlorine for the production of anhydrous carnallite;

- to increase the degree of chlorine use to obtain anhydrous carnallite of the required quality;

- to reduce the amount of sludge;

- to reduce chlorine emissions to gas treatment facilities.

The objective of the invention is to improve the technical and economic indicators of the technology for producing anhydrous carnallite by reducing the consumption of chlorine at the stage of chlorination of the melt, and reducing the cost of gas cleaning of exhaust gases.

The technical result is achieved by the fact that a method for producing anhydrous carnallite is proposed, including loading solid raw materials into a smelting chamber, melting solid raw materials to obtain a melt, feeding the melt into a chlorination chamber with tuyeres, chlorinating it with a chlorine-containing gas, settling and draining anhydrous carnallite; that anode chlorine gas and dried air are fed directly into the tuyeres of the chlorination chamber into the melt at a volume ratio of anode chlorine gas to dried air equal to (0.1-1.0): 1, while the pressure in the tuyeres of the chlorination chamber is maintained at 0.4-1 atm ., regulate the supply of anode chlorine gas and dried air by valves.

To implement the method, a technological line for producing anhydrous carnallite is proposed, including a solid raw material loading unit, a melting chamber, a chlorination chamber with tuyeres, a settling chamber, an anode chlorine gas supply line, an air supply line, an exhaust gas line for gas cleaning, an anhydrous carnallite discharge line, in which is new in that it additionally includes an installation for drying air to obtain dry air, located on the air supply line, a dry air supply line connected on one side with an air dryer, on the other side, a dry air supply line and an anode supply line. chlorine gas are connected directly to the tuyeres of the chlorination chamber, while the dry air supply line and the anode chlorine gas supply line are equipped with dry air and anode chlorine gas supply control valves, and a check valve is installed on the anode chlorine gas supply line.

Supply directly to the chlorination chamber tuyeres into the melt of anode chlorine gas and dried air at a volume ratio of anode chlorine gas to dried air equal to (0.1-1.0): 1, while maintaining the pressure in the chlorination chamber tuyeres of 0.4-1 atm ., as well as the regulation of the supply of anode chlorine gas and dried air by valves allows to reduce the consumption of chlorine for the production of anhydrous carnallite, to increase the degree of chlorine use to obtain anhydrous carnallite of the required quality, to reduce the amount of sludge, and also to reduce chlorine emissions to the gas treatment plant, and thereby reduce costs for neutralization and disposal of waste gases.

It has been experimentally established that the supply of anode chlorine gas and dried air to the melt directly into the tuyeres of the chlorination chamber at a ratio of anode chlorine gas to dried air less (0.1-1.0): 1 will lead to an increase in the degree of hydrolysis of magnesium chloride and to an increase in the formation of sludge, which will lead to deterioration of the chlorination chamber.

When the ratio of anode chlorine gas to dried air is more than (0.1-1.0): 1, it was revealed that passing through the melt layer a significant amount of anode chlorine gas and dried air is not used, and is removed with exhaust gases, which leads to unjustifiably high costs , and complicates the gas cleaning of off-gases. All this affects the economy of the process of obtaining anhydrous carnallite.

A new technological line for the production of anhydrous carnallite with the inclusion of new equipment and connections between them for supplying anode chlorine gas and dried air to the chlorination chamber into the melt makes it possible to reduce the consumption of chlorine for the production of anhydrous carnallite, to increase the degree of chlorine use to obtain anhydrous carnallite of the required quality, to reduce the amount of sludge , as well as to reduce chlorine emissions to gas treatment facilities, and thereby reduce the cost of neutralization and disposal of waste gases.

The claimed group of inventions meets the requirement of unity of invention, since the claimed method for producing anhydrous carnallite and the technological line for its implementation form a single inventive concept.

The applicant's analysis of the state of the art, including a search for patent and scientific and technical sources of information, and the 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 identical (identical) to all essential features of the invention. Determination from the list of identified analogs of the prototype, as the closest analogue in terms of a set of features, made it possible to establish a set of distinctive features essential in relation to the technical result perceived by the applicant in the claimed method for producing anhydrous carnallite and the technological line for its implementation, set out in the claims.

Therefore, the claimed invention meets the "novelty" condition

To check the compliance of the claimed invention with the condition "inventive step", the applicant conducted an additional search for known solutions in order to identify features that coincide with the distinctive features of the prototype of the claimed method for producing anhydrous carnallite and the technological line for its implementation. As a result of the search, no new sources were found and the claimed objects do not follow explicitly for a specialist, since the state of the art, determined by the applicant, did not reveal the influence of the envisaged essential features of the claimed invention of transformations to achieve a technical result. Therefore, the claimed invention meets the "inventive step" criterion.

FIG. 1 shows a technological line for the production of anhydrous carnallite, consisting of a unit 1 for loading solid raw materials, a melting chamber 2, a chlorination chamber 3 with tuyeres 4, a settling chamber 5, an anode chlorine gas supply line 6, a dry air supply line 7, an air drying unit 8, a line 9 air supply, a check valve 10 installed on the anode chlorine gas supply line, a valve 11 for adjusting the anode chlorine gas flow rate, a valve 12 for adjusting the dry air flow rate, an electrolyzer 13, an anhydrous carnallite outlet line 14, an off-gas line 15 connected to the gas cleaning system 16.

Example 1.

In the melting chamber 2 with a capacity of 2.5-3.0 tons, solid raw materials are loaded continuously at a rate of 4-7 tons / hour, consisting of a crushed mixture of magnesium chloride (returnable magnesium chloride) and potassium, sodium and magnesium chlorides in the form of a spent electrolyte obtained in the process of obtaining magnesium by electrolysis of carnallite raw materials containing 4-6 wt. % MgCl ₂ . The spent electrolyte is obtained in the process of electrolytic production of magnesium and chlorine and is periodically removed from the electrolyzer when the content of magnesium chloride in it reaches no more than 6%. Magnesium chloride (recycled magnesium chloride) is obtained as a by-product as a result of the chemical reaction of titanium tetrachloride with magnesium, which is periodically removed from the reduction process by draining into vacuum ladles and then into boxes. From the unit 1 for loading with dispensers, the crushed mixture of returnable magnesium chloride and spent electrolyte is loaded into the melting chamber 2. In the melting chamber 2, electrodes are installed, with the help of which the temperature is maintained at 490-520 ° C, and the solid raw material is melted. The resulting melt flows through the overflow channels into the chlorination chamber 3, where for chlorination under the melt layer, anode chlorine gas and dried air are fed directly into the tuyeres 4 in the amount of 40 m ³ / h of dried air and 40 m ³ / h of anode chlorine gas, which corresponds to the volume ratio of the anode chlorine gas to dry air, equal to 1: 1. Anode chlorine gas containing at least 85 vol.% Cl ₂ is obtained in the process of electrolytic production of magnesium and chlorine (see the book Metallurgy of magnesium and other light metals. - Aidenzon MA M: Iz-vo Metallurgy, 1971, cf. 73 ), and is fed from the electrolyzer 13 through the line 6 of the anode chlorine gas supply directly to the tuyeres 4 of the chlorination chamber 3. Dehumidified air is obtained at installation 8 for air drying; UOV -100 is used as the installation. Dried air in the amount of 40 m ³ / h is fed through the line 7 of the dried air supply directly to the tuyeres 4 of the chlorination chamber 3. The pressure in the lances 4 of the chlorination chamber 3 is maintained at 0.4 atm. The amount of dried air supplied to the tuyeres 4 of the chlorination chamber 3 is controlled by the dry air flow rate adjustment valves 12 installed on the dry air supply line 7, and the amount of anode chlorine gas supplied is controlled by the anode chlorine gas flow rate adjustment valves 11 installed on the anode chlorine gas supply line 6. To exclude the squeezing of the dried air, a check valve 10 is installed on the supply line 6 of the anode chlorine gas. When processing with anode chlorine gas and dried air, the melt is heated using steel electrodes to a temperature of 700-850 ° C, and then from the chlorination chamber 3, the melt with a mass fraction of magnesium oxide is not more than 2.5% by gravity flows into the sludge chamber 5, where sedimentation of magnesium oxide, titanium dioxide and other solid impurities suspended in the melt occurs. The clarified part of the melt of anhydrous carnallite composition, wt. %: 45-52 MgCl ₂ , 0.2-0.8 MgO, 0.9-1.3 NaCl, through the taphole is poured into ladles, and through line 14 of the drainage of anhydrous carnallite is sent to the electrolysis process to obtain magnesium and chlorine. Off-gases are directed to the system of gas-cleaning facilities 16 through the off-gas line 5.

Example 2.

In the melting chamber 2 with a capacity of 2.5-3.0 tons, solid raw materials are loaded continuously at a rate of 4-7 tons / hour, consisting of a crushed mixture of returnable magnesium chloride and spent electrolyte obtained in the process of obtaining magnesium by electrolysis of carnallite raw materials, containing 4-6 masses. % MgCl ₂ . The spent electrolyte is obtained in the process of electrolytic production of magnesium and chlorine and is periodically removed from the electrolyzer when the content of magnesium chloride in it reaches no more than 6%. Returnable magnesium chloride is obtained as a by-product as a result of the chemical reaction of titanium tetrachloride with magnesium, which is periodically removed from the reduction process by pouring into vacuum ladles and then into boxes. From the unit 1 for loading with dispensers, the crushed mixture of returnable magnesium chloride and spent electrolyte is loaded into the melting chamber 2. In the melting chamber 2, electrodes are installed, with the help of which the temperature is maintained at 490-520 ° C, and the solid raw material is melted. The resulting melt flows through the overflow channels into the chlorination chamber 3, where for chlorination under the melt layer, anode chlorine gas and dried air are fed directly into the tuyeres 4 in an amount of 150 m ³ / h of dried air and 15 m ³ / h of anode chlorine gas, which corresponds to the volumetric ratio of the anode chlorine gas to dry air, equal to 0.1: 1. Anode chlorine gas, containing at least 85 vol.% Cl ₂ , is obtained in the process of electrolytic production of magnesium and chlorine (see the book Metallurgy of magnesium and other light metals. - Aidenzon MA M: Iz-vo Metallurgy, 1971, cf. 73), and is fed from the electrolyzer 13 through the line 6 of the anode chlorine gas supply directly to the tuyeres 4 of the chlorination chamber 3. Dehumidified air is obtained at installation 8 for air drying; UOV -100 is used as the installation. Dried air in the amount of 150 m ³ / h is fed through the line 7 of the dried air supply directly to the tuyeres 4 of the chlorination chamber 3. The pressure in the lances 4 of the chlorination chamber 3 is maintained at 1.0 atm. The amount of dried air supplied to the tuyeres 4 of the chlorination chamber 3 is controlled by the dry air flow rate adjustment valves 12 installed on the dry air supply line 7, and the amount of anode chlorine gas supplied is controlled by the anode chlorine gas flow rate adjustment valves 11 installed on the anode chlorine gas supply line 6. To exclude the squeezing of the dried air, a check valve 10 is installed on the supply line 6 of the anode chlorine gas. When processing with anode chlorine gas and dried air, the melt is heated using steel electrodes to a temperature of 700-850 ° C, and then from the chlorination chamber 3, the melt with a mass fraction of magnesium oxide is not more than 2.5% by gravity flows into the sludge chamber 5, where sedimentation of magnesium oxide, titanium dioxide and other solid impurities suspended in the melt occurs. The clarified part of the melt of anhydrous carnallite composition, wt. %: 45-52 MgCl ₂ , 0.2- 0.8 MgO, 0.9-l, 3 NaCl, are poured through the taphole into ladles, and through line 14 of the drainage of anhydrous carnallite is sent to the electrolysis process to obtain magnesium and chlorine. Off-gases are directed to the system of gas-cleaning facilities 16 through the off-gas line 5.

Example 3.

In the melting chamber 2 with a capacity of 2.5-3.0 tons, solid raw materials are loaded continuously at a rate of 4-7 tons / hour, consisting of a crushed mixture of returnable magnesium chloride and spent electrolyte obtained in the process of obtaining magnesium by electrolysis of carnallite raw materials, containing 4-6 masses. % MgCl ₂ . The spent electrolyte is obtained in the process of electrolytic production of magnesium and chlorine and is periodically removed from the electrolyzer when the content of magnesium chloride in it reaches no more than 6%. Returnable magnesium chloride is obtained as a by-product as a result of the chemical reaction of titanium tetrachloride with magnesium, which is periodically removed from the reduction process by pouring into vacuum ladles and then into boxes. From the unit 1 for loading with dispensers, the crushed mixture of returnable magnesium chloride and spent electrolyte is loaded into the melting chamber 2. In the melting chamber 2, electrodes are installed, with the help of which the temperature is maintained at 490-520 ° C, and the solid raw material is melted. The resulting melt flows through the overflow channels into the chlorination chamber 3, where for chlorination under the melt layer, anode chlorine gas and dried air are fed directly into the tuyeres 4 in an amount of 80 m ³ / h of dried air and 40 m ³ / h of anode chlorine gas, which corresponds to the volume ratio of the anode chlorine gas to dry air, equal to 0.5: 1. Anodic chlorine gas, containing at least 85 vol.% Cl ₂ , is obtained in the process of electrolytic production of magnesium and chlorine (see the book Metallurgy of magnesium and other light metals. - Aidenzon M.A.M .: Iz-vo Metallurgy, 1971, p. . 73), and is fed from the electrolyzer 13 through the line 6 of the anode chlorine gas supply directly to the tuyeres 4 of the chlorination chamber 3. Dehumidified air is obtained at installation 8 for air drying; UOV -100 is used as the installation. Dried air in the amount of 80 m ³ / h is fed through the line 7 of the dried air supply directly to the tuyeres 4 of the chlorination chamber 3. The pressure in the lances 4 of the chlorination chamber 3 is maintained at 0.7 atm. The amount of dried air supplied to the tuyeres 4 of the chlorination chamber 3 is controlled by the dry air flow rate adjustment valves 12 installed on the dry air supply line 7, and the amount of anode chlorine gas supplied is controlled by the anode chlorine gas flow rate adjustment valves 11 installed on the anode chlorine gas supply line 6.

To exclude the squeezing of the dried air in the event of an increase in pressure in the lance 4 of the chlorination chamber 4, a check valve 10 is installed on the supply line 6 of the anode chlorine gas 10. When processing with anode chlorine gas and dried air, the melt is heated using steel electrodes to a temperature of of the chlorination chamber 3, the melt with a mass fraction of magnesium oxide not exceeding 2.5% is fed by gravity into the settling chamber 5, where the suspension of magnesium oxide, titanium dioxide and other solid impurities suspended in the melt occurs. The clarified part of the melt of anhydrous carnallite composition, wt. %: 45-52 MgCl ₂ , 0.2-0.8 MgO, 0.9-1.3 NaCl, through the taphole is poured into ladles, and through line 14 of the drainage of anhydrous carnallite is sent to the electrolysis process to obtain magnesium and chlorine. Off-gases are directed to the system of gas-cleaning facilities 16 through the off-gas line 5.

Thus, the proposed method and technological line for producing anhydrous carnallite allows to reduce the consumption of chlorine for the production of anhydrous carnallite, to increase the degree of chlorine use, to reduce the amount of sludge, and to reduce chlorine emissions to gas treatment facilities.

Claims (2)

1. A method for producing anhydrous carnallite, including loading solid raw materials into a smelting chamber, melting solid raw materials to obtain a melt, feeding the melt into a chlorination chamber with tuyeres, chlorinating it with a chlorine-containing gas, settling and draining anhydrous carnallite, characterized in that directly into the tuyeres of the chlorination chamber anode chlorine gas and dried air are fed into the melt at a volume ratio of anode chlorine gas to dried air equal to (0.1-1.0): 1, while the pressure in the tuyeres of the chlorination chamber is maintained at 0.4-1 atm, the supply of anode chlorine gas and dried air is regulated by valves. 2. Technological line for obtaining anhydrous carnallite, including a unit for loading solid raw materials, a smelting chamber, a chlorination chamber with tuyeres, a settling chamber, an anode chlorine gas supply line, an air supply line, an exhaust gas line for gas cleaning, an anhydrous carnallite discharge line, characterized by that it additionally includes an air drying unit to obtain dry air, located on the air supply line, a dry air supply line connected on one side with an air dryer, and on the other side with dry air supply and anode chlorine gas supply lines connected directly to lances of the chlorination chamber, while on the dry air supply line and the anode chlorine gas supply line, valves for regulating the supply of dried air and anode chlorine gas are installed, and a check valve is installed on the anode chlorine gas supply line.

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