WO2024196282A1 - Method and apparatus for producing lithium chloride monohydrate - Google Patents

Abstract

The present invention relates to methods for concentration by evaporation, methods for obtaining a product from a concentrate, and devices for carrying out same using vertical columns by passing a hot heat transfer medium through a liquid, and relates more particularly to concentrating lithium-containing solutions by the evaporation of water and to producing lithium chloride monohydrate. The invention can be used for concentrating and purifying lithium chloride solutions at natural brine extraction sites, as well as in process chains during the enrichment of lithium chloride solutions for the subsequent production of lithium chloride monohydrate or for other purposes. The present method reduces the cost of producing a purified lithium chloride concentrate and lithium chloride monohydrate under cold climate conditions, using readily available gas as fuel.

Description

METHOD AND APPARATUS FOR PRODUCING LITHIUM CHLORIDE MONOHYDRATE

Field of technology

The invention relates to methods for concentrating lithium-containing solutions by evaporation using vertical columns by passing a hot coolant through the liquid, followed by obtaining lithium chloride monohydrate, and devices for implementing them.

The aim of the invention is to obtain lithium chloride concentrate with its parallel purification from impurities in an optimal way in the conditions of the Russian climate using available energy resources with subsequent production of lithium chloride monohydrate, wherein the initial lithium chloride solution can be of both industrial and natural origin, gas combustion products are used as a source of heat carrier, including the possible use of associated gas obtained during oil production as fuel.

The proposed invention can be used for concentrating lithium chloride solutions and subsequently obtaining lithium chloride monohydrate at sites where natural brines are extracted and as part of process chains for further obtaining lithium compounds for industrial purposes.

State of the art The end of the 20th century was marked by a rapid expansion of the raw material base for the production of lithium products due to the involvement of hydromineral raw materials - lithium-bearing natural brines, salars, and lake brines - in the sphere of industrial production.

The main amount of lithium is concentrated in the waters of the World Ocean (260 billion tons). In continental natural waters and brines together with solid aluminosilicate raw materials, the lithium content on Earth is ~30 million tons. At the same time, the share of continental natural waters and brines (surface and deep) accounts for 78% and only 22% - for ore pegmatite raw materials.

The use of ore aluminosilicate raw materials requires large capital investments for its extraction. In addition, energy costs are required for the implementation of the technology: high-temperature sintering of the charge (1350 °C) and subsequent leaching of the cakes at 90 °C. Hence the high cost of lithium products.

When using hydromineral raw materials, no mining operations are required for their extraction, and the leaching of valuable components from the host rocks is carried out by nature itself. The content of such components in brines as lithium, sodium, potassium, magnesium, calcium salts, as well as bromine and a number of microcomponents, allows them to be extracted by precipitation and ion-exchange methods, which do not require large energy costs. With the complex processing of this type of raw material, it is possible to significantly increase the economic efficiency of the technology as a whole by reducing the cost of the products obtained, including lithium.

The production of lithium products from hydro-mineral raw materials has stimulated the growth of new areas of application of lithium compounds, primarily in the synthesis of cathode materials for lithium-ion batteries. current sources, in expanding the composition of compositions in obtaining ultra-light alloys, etc.

Recently, there has been a worldwide trend towards the complex use of hydromineral raw material sources - natural mineralized brines of various types. One of the main advantages of extracting useful elements from this raw material is the higher quality of the resulting products.

The easiest to industrially develop are lithium-bearing brines of the sodium chloride type, in which the content of magnesium and calcium salts is small. In world practice, technologies for their processing have been mastered, the main principle of which is the preliminary concentration of brines for lithium in evaporation pools before obtaining lithium concentrate.

Methods of brine solar concentrating are widely used in industry, in particular, they are indicated in patents RU2283283C1 [1] and CN1 05540619B [2], this technology has its drawbacks, in particular, it is highly dependent on climatic conditions, including the number of sunny days per year and the amount of precipitation at the location of the evaporation basin, so this method has found wide application in China and South America.

In Russia, a process flow chart based on natural brine concentration was developed by N.I. Zabrodin for the waters of the Berikey deposit [3] (Republic of Dagestan). In this flow chart, concentration was carried out in basins, after which Mg(OH)2, CaCO3, BaCO3+BgCO3 were precipitated in stages, and further concentration of the solution was carried out in factory conditions under vacuum. A technical and economic report on the feasibility study for the construction of a chemical plant based on this mineralized mineral deposit water after the examination by the All-Russian Research Institute of Galurgy was not assessed positively due to the high capital and operating costs, as well as the long payback period of the enterprise.

The technology of solar concentrating is very limited in application, including due to the impossibility of transporting the initial raw materials to the places of its preferred use.

The prior art also includes a method of direct osmosis for concentrating solutions of lithium-containing salts, patent application WO2016064689A2 [4].

The method utilizes the osmotic pressure difference between a lithium-containing brine and a second brine with a higher osmotic pressure, and describes a process in which reverse osmosis process technology and forward osmosis process technology are used in tandem to concentrate lithium-containing salt solutions and to recover water that can be reused in the process.

This process has a number of disadvantages: during the process of concentrating solutions, contamination of semipermeable membranes occurs, which require cleaning or replacement; to extend the service life of the membranes, preliminary cleaning of the concentrated solution is required, which complicates the design and makes the scheme of little use for large volumes of solutions, especially brines of natural origin. Also, the membranes have limited resistance to many salts present in the brine, especially calcium salts.

A method for extracting lithium from solutions using an ion exchange process based on inorganic ion exchange materials is known from the prior art, for example, this method is described in patent US10505178B2 [5], in particular, the method is applicable for obtaining concentrated lithium solution, but its provision requires expensive consumables, such as ion exchange resin, the method requires regeneration of the ion exchange material and a complex design of the installation, also the ion exchange material becomes contaminated during use, which requires either careful pre-cleaning of the solution or periodic replacement of the expensive material, this cleaning method also has a low speed.

In a general sense, the concentration of aqueous solutions to produce a concentrated salt solution is widely used in industry; methods and devices have been developed that function, but are not ideal for working with lithium chloride brine.

Thus, a method for evaporating mineralized waters according to patent SU1680634A1 [6] is known from the state of the art, in which evaporation of mineralized waters using flue gases in a packed scrubber is carried out with additional heating of the packing, the presented method is intended for working with flue gases up to 200°C. Additional heating of the packing is associated with additional energy costs, and the method also does not disclose the issue of preparing the heat carrier, utilizing the residual heat of the steam-gas mixture, cleaning sediments and the optimal evaporation mode for a specific type of solution.

Also known from the prior art is a spray evaporator circuit according to patent US2327039A [7], the design of this device does not provide for the utilization of residual heat of the steam-gas mixture, purification of sediments and an optimal evaporation mode for a specific type of solution. The prior art discloses a method for evaporating sodium sulfate solutions and isolating sodium sulfate from them according to patent US2640762A [8], this method also does not provide for the utilization of residual heat of the steam-gas mixture, and has a complex configuration of the evaporation column for scaling the installation, as well as for its maintenance during operation.

The prior art discloses a modern installation for concentrating wastewater and creating brines according to patent US11390791B2 [9], which was chosen as a prototype, consisting of:

1. Concentrator sections, which include:

1.1 Gas inlet;

1.2 Gas outlet;

1.3 A mixing corridor located between a gas inlet and a gas outlet, wherein the mixing corridor has a narrowed section in which the gas flow within the mixing corridor accelerates as it moves from the gas inlet to the gas outlet;

1.4 A liquid inlet through which the liquid to be concentrated is injected into the mixing corridor, the liquid inlet being located in the mixing corridor between the gas inlet and the constricted portion;

2. A drip collector located downstream of the concentrator section, which includes:

2.1 Drip collector;

2.2 Gas flow channel connected to the gas outlet of the concentrator section;

2.3 A liquid collector located in the gas flow channel of the mist collector for removing liquid from the gas flowing in the channel, the liquid collector contains a coarse cleaning reflective baffle (drip collector) and a reservoir that collects the liquid removed from the gas flowing in the channel;

3. A recirculation circuit located between the tank and the mixing corridor to transport liquid from the tank to the mixing corridor;

4. Secondary recirculation circuit, including a settling tank for separating saturated liquid and suspended solids;

5. A special device for mixing brine, connected to a settling tank.

The following are indicated as dependent claims in patent US11390791B2:

2. The concentration unit according to claim 1, characterized in that the special device for mixing brine includes a port for extracting saturated liquid, a valve for extracting saturated liquid, operatively connected to the port for extracting saturated liquid, a port for extracting settled solids, a valve for extracting settled solids, operatively connected to the port for extracting settled solids, and a controller operatively connected to the port for extracting settled solids, connected to the saturated liquid valve and the settled solids valve.

3. The concentration apparatus of claim 2, wherein the special brine mixing device includes a lubricant source that is fluidly connected to the mixing line downstream of the point at which the saturated liquids and settled solids are mixed.

4. The concentration unit according to item 3, wherein the controller is functionally connected to a mixture weight sensor, a saturated liquid weight sensor, and a settled solid particles weight sensor. 5. The concentration unit according to claim 1, characterized in that the concentrator section includes an adjustable flow limiter located in the narrowed portion of the mixing corridor, wherein the flow limiter can be adjusted to change the flow of gas through the mixing corridor.

6. The concentration apparatus of claim 5, wherein the adjustable flow restriction is a Venturi plate that can be adjusted to change the size or shape of the narrowed portion of the mixing corridor.

7. The concentration unit according to item 1, wherein the liquid collector additionally comprises a first removable filter.

8. The concentration unit according to item 7, wherein the first removable filter is designed to remove liquid droplets of 20 microns or more in size.

9. The concentration apparatus according to item 7, additionally comprising a second removable filter.

10. The concentration unit according to item 9, wherein the second removable filter is designed to remove liquid droplets of a smaller size than the first removable filter.

This installation was chosen as a prototype of the installation for concentration, since the purpose of its application is to obtain concentrated solutions of salts by evaporation from solutions of a solvent (water) in direct contact of the liquid with the heat-transfer gas. The device has a mixing corridor with an inlet for injection of the concentrated liquid; a storage tank for collecting the concentrate; a recirculation circuit connecting the tank for the concentrate and the mixing corridor; an outlet for gas. The disadvantages of the prototype are:

- To mix the coolant and liquid in the concentrator of the installation, a Venturi scrubber (Venturi tube) is structurally implemented; the disadvantage of this configuration for the purposes of our invention is the wear of the inner surface of the diffuser due to high-speed contact with particles, including salt crystals and impurities that may be contained in the solution.

- The absence of a centrifugation system for the effective separation of impurities from the concentrated solution; for the purposes of our invention, the key is to reduce the loss of lithium chloride during the separation of precipitates while ensuring the required purification rate; the design declared in the prototype does not ensure the implementation of this method.

- The absence of a system for the recovery of thermal energy from the steam-gas mixture, the conservation of thermal energy is a necessary requirement for ensuring the energy efficiency of the installation, especially in cold climate conditions, which is necessary for the purposes of our invention.

- The prototype tank, which collects the liquid removed from the gas flowing in the channel, contains an inclined tray for collecting sediment, which, due to its geometry, can be subject to overgrowth by precipitated crystals, which prevents their effective removal, necessary for the purposes of our invention.

- The shape of the concentrator channel has a complex geometry and provides for the placement of a plate for flow regulation (dependent feature, clause 6 of the prototype formula), the gas outlet channel and the liquid collector with drip collectors have a complex configuration, which complicates the manufacture and maintenance of the installation; for the purposes of our invention, a more technologically advanced design is required. Although a concentrated solution of lithium chloride can act as a stand-alone product, the most practical option seems to be its further processing in order to obtain lithium chloride monohydrate for convenient transportation and use as an independent finished product.

Disclosure of invention

The invention is based on the solution of the technical problem of obtaining lithium chloride concentrate and its purification from impurities in an optimal way with subsequent production of lithium chloride monohydrate, or without it, in the climate conditions of Russia using available energy resources, the solution ensures a reduction in lithium chloride losses in the concentrated solution during the removal of sediments, simplification of the design of the installation to ensure the evaporation method by combining the process of evaporation and purification of the solution, an increase in the energy efficiency of the method due to the recirculation of thermal energy.

The patented methods and designs are effective and cost-effective when working with lithium chloride solutions of both industrial and natural origin in areas with cold climates and accessible gas as fuel, for example, obtained during oil production at fields with parallel brine production.

The stated technical task is achieved by implementing a method for concentrating a lithium chloride solution by evaporating part of the water from the liquid, characterized in that a lithium-containing medium is used as the initial solution for concentration; a stream of hot gas obtained using a gas heat generator is used as the heat carrier; the evaporation of water is carried out in an evaporation unit, which is a combined unit with a column with a circulation thickener tank, with liquid spraying from top to bottom in the coolant flow; an operating mode of the evaporation unit is used in which the concentration of the resulting concentrated solution for lithium chloride is brought to 430 g/ ^dm3 or more, which ensures the salting out of impurity salts while maintaining lithium chloride in a dissolved state and obtaining a product concentrate; impurities falling out of the evaporated lithium chloride solution are deposited in the circulation thickener tank of the evaporation unit, located below the column of the evaporation unit, and are separated from the solution by centrifugation; the steam-gas mixture obtained after contact with the solution is removed from the evaporation unit through a heat exchanger with the return of part of the thermal energy to the system; when implementing the method, additional evaporation of water from the surface of the solution in the circulation thickener tank of the evaporation unit can be carried out; when implementing the method, the lithium-containing medium may be a brine of natural origin; when implementing the method, the lithium-containing medium may be a solution after a reverse osmosis filtration operation in the technology of extracting lithium from natural brines.; when implementing the method, the lithium-containing medium may be a solution after a brine nanofiltration operation; when implementing the method, the lithium-containing medium may be a primary lithium concentrate obtained using the DGAL-S1 sorbent; when implementing the method, the associated gas produced with oil may serve as fuel for the gas heat generator; when implementing the method, the portion of thermal energy returned to the system may be spent on heating the original solution; when evaporating in a continuous, steady-state mode, a portion of the impurity-free and concentrated as a result the evaporation of the lithium chloride solution can be withdrawn as a product concentrate, and a portion, after mixing with the flow of the initial solution supplied for evaporation as a lithium-containing medium, can be returned to the evaporation stage; when implementing the method, the product concentrate can be withdrawn from the system through a heat exchanger with a portion of the thermal energy being returned to the system; when implementing the method, the thermal energy can be used to heat the air supplied to the heat generator; when implementing the method, the solution returned to the evaporation stage can be passed through a filter; when implementing the method, during the passage of the steam-gas mixture formed by the contact of the coolant and the solution through the heat exchanger, condensate can be formed, which can be collected and removed from the system; when implementing the method, perforated plates can be used in the evaporation unit column; when implementing the method, hot gas can be fed into the evaporation unit column from the bottom up; when implementing the method, the gas temperature at the outlet of the evaporation unit column may not exceed 100°C; when implementing the method, when cooling the coolant to a temperature below the dew point temperature, hot gas may be additionally fed to the upper part of the evaporation unit column to increase the temperature; when implementing the method, before feeding the hot gas to the evaporation unit column, the hot gas may flow around the surface of the solution in the circulating thickening tank of the evaporation unit; when implementing the method, the hot gas may be fed to the evaporation unit at a temperature of from 400°C to 800°C; when implementing the method, air may be additionally mixed into the coolant to regulate the temperature and volume, and the air may be mixed in a vortex mixer; when implementing the method, a cyclone-type gas heat generator may be used; when implementing the method the lithium chloride product concentrate can be taken from the circulating thickening tank of the evaporation unit; when implementing the method, the steam-gas mixture obtained after the contact of the heat carrier with the solution can be sent to a drip collector with the collected liquid being removed to the circulating thickening tank of the evaporation unit; when implementing the method, the steam-gas mixture obtained after the contact of the heat carrier with the solution can be sent to a drip collector with the collected liquid being removed to the original solution; when implementing the method, in order to accelerate the salting out of impurities, the circulating thickening tank of the evaporation unit can be additionally cooled; when implementing the method, after centrifugation of the precipitated impurities, they can be washed in the following order: the cake is unloaded into the first reactor with a stirrer; a portion of the washing liquid from the first container with the washing liquid is introduced into the first reactor with a stirrer and pulped; the resulting suspension is sent for centrifugation; the centrate is returned to the evaporation unit, the cake is discharged into the second reactor with a stirrer; a portion of the washing liquid from the second tank with the washing liquid is introduced into the second reactor with a stirrer and pulped; the resulting suspension is sent for centrifugation; the centrate is sent to the first tank with the washing liquid, the cake is discharged into the second reactor with a stirrer; a portion of fresh water is introduced into the second reactor with a stirrer and pulped; the resulting suspension is sent for centrifugation; the centrate is sent to the second tank with the washing liquid, the cake is discharged, while the condensate obtained during cooling of the withdrawn steam-gas mixture, which was formed by contact of the coolant and the solution, can be used as fresh water; when implementing the method, the heat exchanger can be additionally cooled using cooling towers; when implementing the method, hot gas can be fed into the column of the evaporation unit from top to bottom; when implementing the method, hot gas can be fed into the column of the evaporation unit at a temperature of 400°C to 800°C, while at the outlet of the column of the evaporation unit, the steam-gas mixture can have a temperature of 78°C to 120°C; when implementing the method, part of the exhaust gas mixture can be sent to a heat generator; when implementing the method, the selection of the product concentrate of lithium chloride can be carried out from the centrate after the centrifugation operation.

The stated technical task is achieved by using a device for concentrating a lithium chloride solution by evaporating a portion of the water from the liquid, which device includes a gas inlet; an evaporation unit, which is a column combined with a circulating thickening tank, with an injection system for injecting the concentrated liquid; a recirculation loop connecting the circulating thickening tank of the evaporation unit and the column of the evaporation unit; a gas outlet, characterized in that a gas heat generator is installed in front of the gas inlet; the column of the evaporation unit is designed as a cylindrical vertical column; the system for injecting the concentrated liquid into the column of the evaporation unit is located in the upper part of the column of the evaporation unit and is designed as one or more sprayers located in the internal volume of the column of the evaporation unit, or located on the body of the column of the evaporation unit, ensuring direct contact of the liquid and gas; the circulation tank-thickener of the evaporation unit is located below the column of the evaporation unit and has a narrowing at the bottom; the lower part of the circulation tank-thickener of the evaporation unit is connected to the centrifuge, and there is a channel for returning the separated liquid phase after centrifugation into the evaporation unit; after the gas outlet, a heat exchanger with a condensate collection system is installed, providing heating of the initial solution; wherein a filter can be additionally installed in the recirculation circuit connecting the circulation thickener tank of the evaporation unit and the column of the evaporation unit; wherein plates with holes can be installed in the column of the evaporation unit; wherein the gas inlet can be located so that the gas is fed into the column of the evaporation unit from the bottom up; wherein a channel for additional admixture of air into the coolant can be installed after the gas heat generator; wherein a vortex mixer can be installed after the gas heat generator for additional admixture of air into the coolant; wherein the gas heat generator is designed according to the cyclone scheme; a drip collector with a channel is installed, providing the removal of the captured liquid into the circulation thickener tank of the evaporation unit; wherein after the gas outlet a drip collector with a channel ensuring the removal of the captured liquid into the initial solution can be installed; wherein the circulation thickener tank of the evaporation unit can have a channel for the selection of the product concentrate of lithium chloride, wherein a heat exchanger can be installed on the channel for the selection of the product concentrate of lithium chloride, which takes heat from the product concentrate, as well as an air blower that directs the cooled portion of the exhaust gas mixture into a gas heat generator, wherein the line for removing the centrifuge fugate from the centrifuge can be connected to the channel for the selection of the product concentrate of lithium chloride; wherein after the gas outlet there can be; wherein the circulation thickener tank of the evaporation unit can be equipped with a cooler; wherein the centrifuge for separating impurities can be connected to a reactor equipped with a stirrer, the reactor in turn can be connected to a line for removing pulp and to a tank containing a washing solution; the line for removing pulp can be connected to a second centrifuge, the second centrifuge can be connected to a circulation thickener tank of the evaporation unit, to a channel for unloading cake, to a tank containing a washing solution and to a second reactor equipped with a stirrer, the second reactor equipped with a stirrer can be connected to the inlet of the second centrifuge; wherein a cooling tower can be installed for additional cooling of the heat exchanger; wherein the gas inlet can be located so that the gas is fed into the column of the evaporation unit from top to bottom.

The stated technical task is achieved by implementing a method for obtaining lithium chloride monohydrate from lithium chloride concentrate obtained by the above-described method; in order to obtain lithium chloride monohydrate, the concentrate is evaporated with heating steam until a suspension containing lithium chloride monohydrate crystals is formed; the suspension is centrifuged, the obtained centrate is returned to the stage of obtaining the concentrate, and the cake is washed with water and the suspension obtained after washing is sent for centrifugation; after centrifugation, the cake in the form of lithium chloride monohydrate crystals is discharged; in this case, the steam obtained during the evaporation of the lithium chloride concentrate can be sent for condensation with the removal of the condensate; In this case, washing the cake with water can be carried out in three stages: at the first stage of washing, the cake is pulped with the addition of water and the resulting pulp is sent for centrifugation; the cake is sent to the second stage of washing, and the centrate is mixed into the original lithium-containing solution for concentration; at the second stage of washing, the cake is pulped with the addition of water and the resulting pulp is sent to centrifugation, the cake is sent to the third stage of washing, and the centrate is mixed into the initial lithium-containing solution for concentration, at the third stage the cake is pulped with the addition of water and a suspension is obtained; in this case, the centrate mixed into the initial solution can be preheated due to the residual heat of the steam-gas mixture, which was formed by the contact of the heat carrier and the solution.

The stated technical task is achieved in that a device for obtaining lithium chloride monohydrate is used, which includes the above-described device for concentrating a lithium chloride solution by evaporating a portion of the water from the liquid, connected to a product concentrate receiving line, which ensures the supply of product concentrate to an evaporation column for precipitation of lithium chloride monohydrate; the evaporation column for precipitation of lithium chloride monohydrate has a channel for removing condensate at the bottom, a channel for the inlet of a heat carrier, a channel for the outlet of moisture-saturated steam, a channel for removing a suspension containing lithium chloride monohydrate crystals; the channel for the outlet of moisture-saturated steam is connected to a heat exchanger; the channel for removing the suspension containing lithium chloride monohydrate crystals is connected to the first centrifuge, which has a centrate return channel and a cake discharge channel; the centrate return channel is connected to the evaporation column for precipitation of lithium chloride monohydrate; the cake discharge channel is connected to a depulping reactor equipped with a stirrer; the depulping reactor is connected to a second centrifuge and to a washing liquid supply line; the second centrifuge is connected to a container with an initial lithium-containing solution for directing the centrate into it and to a second depulping reactor equipped with a stirrer; the second centrifuge is connected to a lithium chloride monohydrate discharge channel. The features incorporated into the method and the design of the device for its implementation ensure the best achievement of the technical result when working with lithium chloride solutions in a manner not obvious from the state of the art for the following reasons:

- A typical solution of lithium chloride of natural or industrial origin usually contains potassium, sodium, magnesium, calcium chlorides, _etc. as impurities. _Lithium chloride, which has the highest solubility, accumulates when the solution is concentrated, and the process of salting out of impurities occurs, NaCl, KCl, _{CaCl2 , MgCl2-6H2O} , _CaBO3-2H2O , _MgBO3-2H2O , _CaSO4-2H2O , _{CaCl2-6H2O precipitate} . It has been determined in pilot plants that effective salting out for lithium chloride solutions is ensured at a solution concentration of lithium chloride of 430 g/ _dm3 or ^more . The technical result is achieved by the fact that the process of gas-thermal evaporation and purification from impurities occurs in parallel in the described method, which ensures the production of lithium chloride concentrate with simultaneous purification from impurities in a single process, which in turn simplifies the design of the installation for implementing the method and the technological process for obtaining purified product concentrate. Thus, the method is optimal for lithium chloride solutions.

- The use of gas-thermal evaporation for lithium chloride solution ensures a minimal risk of solid-phase deposits on the active elements of the evaporation equipment due to the absence of overheated structural elements during the evaporation process, since temperature changes occur only in the volume of the gas-liquid layer.

- The degree of concentration of the initial lithium chloride solution entering the gas-thermal concentration is not important. The difference in the evaporation of lithium solutions with different initial The concentration of lithium chloride will depend only on the consumption of the coolant and the evaporation time.

- The use of flue gas for the concentration of lithium chloride ensures the presence of a large amount of CO2 in the heat-transfer gas, which in turn ensures the saturation of the solution with carbon dioxide, as a result of which the solution is partially purified from Ca and Mg impurities, which also precipitate from the complex solution, the boron impurity contained in the solution can also be reduced.

- The use of a centrifugation system for separating impurities from the concentrated solution ensures a reduction in lithium chloride losses during sediment separation due to the possibility of returning the centrate to the evaporation unit while maintaining the required purification rate; this method, unlike filtration or other purification methods, is optimally suited for the lithium chloride concentration method due to its simplicity and continuity of the process; it does not require filter cleaning or other additional operations.

- Recovery of thermal energy from the steam-gas mixture ensures fuel savings and maintains the operability of the method in cold climate conditions by compensating for heat leaks from the housing and pipelines of the unit.

- The use of gas-thermal evaporation for lithium chloride solution ensures high efficiency of thermal energy use due to direct contact of the gaseous coolant with the evaporated solution under conditions of a highly developed phase contact surface.

- The configuration of the evaporation unit column in the form of a conventional cylinder simplifies the production and maintenance of installations using the proposed method and design. - The use of gas as fuel for the heat generator in the method is compatible with the process of brine extraction at fields where associated petroleum gas is obtained. Combustion of associated petroleum gas in a lithium chloride solution concentration unit, as an alternative to simple combustion of this gas in the atmosphere, allows the use of this little-demanded energy source and a partial reduction in CO2 emissions due to their absorption by the solution, which also reduces damage to the environment.

- Obtaining lithium chloride monohydrate using the specified concentration method ensures the continuity of the process with all the advantages described above.

The described technical solutions, aimed at achieving a technical result, ensure a reduction in the costs of obtaining purified lithium chloride concentrate and lithium chloride monohydrate in cold climate conditions and the availability of gas as fuel.

Description of drawings.

Fig. 1. Scheme of the first industrial installation for concentrating lithium chloride solution.

Fig. 2. Scheme of the second industrial installation for concentrating lithium chloride solution.

Fig. 3. Scheme of the installation for obtaining lithium chloride monohydrate.

Implementation of the invention.

The achievement of the specified technical result is confirmed by the successful implementation of the declared method on three industrial installations.

In the process of developing the technology and design solutions on these installations, the optimal requirements for the temperature conditions specified in the method and the composition of the installation units to ensure the method were determined. Thus, the optimal temperature of the coolant on at the entrance to the evaporation zone is defined within the range from 400°C to 800°C. For the scheme with the supply of the heat carrier to the column of the evaporation unit from the bottom up, the temperature of the steam-gas mixture leaving the column of the evaporation unit should not exceed 100°C, since this leads to undesirable condensate breakthrough. For the scheme with the supply of the heat carrier to the column of the evaporation unit from the top down, the temperature of the steam-gas mixture leaving the column of the evaporation unit for the implementation of the method can be from 78°C to 120°C.

Example 1.

The diagram of the first industrial plant for concentrating lithium chloride solution is shown in Fig. 1

The operation of the unit is based on the counter-current direct contact of a high-temperature gaseous coolant with an aqueous solution of lithium chloride. In this case, there is an intensive evaporation of water in the lithium chloride solution, accompanied by forced cooling of the gaseous coolant with its saturation with water vapor and enrichment of the solution in lithium chloride, i.e. its concentration. In the steady state, the solution and gas, when leaving the direct contact, have the same temperature, equal to the value of the wet-bulb temperature, characteristic of the given system.

In accordance with the presented circuit diagram of the apparatus, gaseous technical propane-butane (PBT) from the PBT source (1) enters the gas burner (4), located tangentially in the cyclone furnace (3). In turn, the ventilation unit (2) pumps atmospheric air into the gas burner and the end nozzle of the cyclone furnace to ensure conditions for deep combustion of PBT. Ignition of the gas-air mixture is carried out using the ignition protection device (IPD) attached to the cyclone furnace. The volumetric flow rates of the supplied air are regulated by dampers Ш-2 and Ш-3. The flue gas formed in As a result of PBT combustion in air, it has a temperature of 1000°C, it is cooled by diluting it with atmospheric air in a vortex mixer (5). Air entering the vortex mixer inlet is pumped by a ventilation unit (2). Air flow is regulated by damper Ш-1. At the outlet of the heat generator, the gaseous coolant has a temperature of 400-800°C at an excess pressure of 0.5 to 1.0 kPa. Then the coolant enters the evaporation unit (6) through the inlet pipe. The evaporation unit is a column with failure-type plates combined with a circulation thickener tank. The circulation thickener tank of the evaporation apparatus is filled with a concentrated solution of lithium chloride to a specified level. Irrigation of the evaporation unit column is provided by a circulation pump (10), which supplies lithium chloride solution to the evaporation unit column through mud filters (11-1, 11-2) and a nozzle. In this case, one of the filters operates in the tract, and the other is in reserve. Switching mud filters to operation and to reserve is carried out by taps K-1, K-2, K-3, K-4.

Before being fed to the evaporation unit column, the concentrated lithium chloride solution is mixed with the feed solution supplied by the metering pump (9) from the feed solution source (8) at the suction of the circulation pump. In turn, the high-temperature heat carrier supplied to the tank section of the evaporation unit comes into surface contact with the LiCl solution, is partially cooled by evaporation of water from the surface and enters the inlet of the evaporation unit column with trays. As a result of the counter-current contact of the high-temperature gas and the solution, a foam layer with a highly developed and constantly renewed phase contact surface is formed on the tray of the evaporation unit column, which ensures forced cooling of the gas and intensive evaporation of water from the LiCl solution. Due to the fact that when mixing the concentrated chloride solution lithium with the initial solution, partial dilution of the solution occurs, the diluted solution after contact with the coolant is concentrated to the initial state, which it had before mixing with the initial solution. In this case, part of the concentrated (productive) LiCl solution is constantly removed to the tank for receiving the productive lithium concentrate (19). In the steady-state operating mode of the evaporation unit column, the gas temperature at the outlet of the last downcomer plate along the gas flow and the reflux solution at the outlet of this plate have a temperature equal to the wet-bulb temperature, the value of which depends on the initial moisture content of the gaseous coolant, its temperature, the temperature of the feed stream of the initial solution and the concentration of the LiCl solution, and is in the temperature range of 74-79 ° C for the system under consideration, while an increase in the temperature at the outlet of the evaporation unit column above 100 ° C leads to an undesirable breakthrough of condensate.

In view of the fact that heat losses are inevitable during the evaporation process even under conditions of ideal thermal insulation of equipment, gas ducts and pipelines, in order to eliminate the risk of condensation of water vapor from the coolant flow in the gas duct at the outlet of the evaporation unit column and in the drop collector of the dispersed solution (13) when cooling the coolant to a temperature below the dew point temperature, a small flow of the initial gaseous coolant having a temperature of about 675°C is fed through the bypass (12) to the gas outlet of the evaporation unit column, mixing with the flow of cooled and extremely saturated with water vapor coolant, ensuring an increase in the temperature of the mixed flow by 3-4°C. the flow rate of the high-temperature coolant fed to the gas outlet of the evaporation unit column is controlled by a high-temperature control valve (HTRV). The drip collector (13) is designed to remove droplets of LiCl solution from the coolant flow to reduce lithium losses on the one hand, and to eliminate the risk of obtaining water vapor condensate with an increased salt content on the other.

The coolant flow, freed from solution droplets, is directed to the intertube space of the contact heat exchanger-condenser (14). The contact heat exchanger-condenser (CHEC) has two cooling circuits. In the first circuit, the initial lithium brine is used as a coolant moved through the pipes, which is heated to 40-45°C during cooling of the coolant flow and directed to the operation of obtaining primary lithium concentrate (a variant of the initial solution), based on the use of the lithium chloride-selective granulated sorbent DGAL-S1. Due to the fact that the flow of the initial lithium-bearing brine used to obtain the primary lithium concentrate fed to the first cooling circuit of the CHEC is insufficient to cool the gaseous coolant to room temperature, a second cooling circuit is used, through the pipes of which a flow of water is passed as a coolant. In this case, the cooling of the coolant in the second circuit of the KTAN can be implemented both in a closed system, by removing the heat acquired by the water in the cooling tower (18), and in an open system if it is necessary to use fresh water heated to 40-60 ° C in production. The water vapor condensate (demineralized water) formed in the intertube space is sent to the condensate receiving tank (16). To increase the heat transfer coefficient from the gas phase to the cooling surface, the latter is irrigated with condensate supplied by a pump (17). The coolant cooled in the KTAN is sent to the mist collector to remove the condensate phase dispersed in it in the form of fog. The movement of the coolant through the gas-thermal evaporation equipment The installations are carried out under vacuum created by a ventilation unit installed at the outlet of the mist collector.

Solid-phase impurities actively released from the solution during gas-thermal concentration upon reaching _a solution concentration of 430 _g / _dm3 or ^more in terms of lithium chloride (NaCl, KCl, _CaCl2 , _MgCl2-6H2O , CaBO3-2H2O _, MgBO3-2H2O, _CaSO4-2H2O , _{CaCl2-6H2O )} are removed in the form of a thickened suspension from the _conical zone of the evaporation unit's circulation thickener tank into a centrifuge ( ₂₀ ) with the KSh-2 ball valve open (KSh-1 is closed in this case), where the suspension is centrifuged. In this case, the resulting cake is discharged into a reactor with a stirrer (21), and the centrate is returned to the tank part of the evaporation unit.

A portion of the first washing liquid from the tank (27) with valves K-15, K-11 open and valves K-12, K-16, K-17 closed is pumped by pump (26) into the reactor (21) and the cake is pulped to a suspension. The resulting suspension is sent for centrifugation in the centrifuge (22) by the pulp pump (25) with valve K-6 open and valve K-8 closed. The centrate is returned to the circulation thickener tank of the evaporation unit (valve K-7 open, valves K-9 and K-10 closed), and the cake is discharged into the reactor with a stirrer (23). Into the reactor (23) by pump (26) with valve K-16 open and valves K-15 and K-17 closed (valve K-11 closed, valve K-12 open) from the tank

(28) pump in the second portion of the washing solution and pulp the cake to a suspension, which is sent by the pulp pump (24) to centrifuge in the centrifuge (22) (tap K-6 is closed, tap K-8 is open). The fugate is sent to the tank (27), obtaining the first washing solution. The washed cake is unloaded into the reactor (23). Then into the reactor (23) from the tank

(29) the third portion of the washing liquid is pumped using pump (26), which is demineralized water (condensate) (taps K-15, K-16, K-11 are closed, taps K-12 and K-17 are open), the contents pulped, the resulting suspension from the reactor (23) is sent to centrifugation in the centrifuge (22) by the pulp pump (24) (taps K-8 are open, taps K-6, K-7, K-9 and K-10 are closed). The fumed sediment is sent to the tank (28), obtaining the second washing solution (tap K-10 is open, taps K-6, K-7, K-8 and K-9 are closed). The sediment washed three times is unloaded onto a trolley with a tray (30). A fresh portion of demineralized water is poured into the tank (29) with tap K-17 closed.

The scheme provides for the washing away of the dense sediment of impurities, which can form in the conical part of the circulation tank-thickener of the evaporation unit as a result of an emergency stop. For this purpose, with the K-14 valve and the KSh-2 ball valve closed and the K-13 valve and the KSh-1 ball valve open, a clarified solution of lithium chloride is supplied from the clarified zone of the circulation tank-thickener of the evaporation unit by a high-performance pump (10), ensuring the washing away of the compacted sediment, which prevents its unloading.

Example 2.

The diagram of the second industrial plant for concentrating lithium chloride solution is shown in Fig. 2.

The operation of the second unit is based on the concurrent contact of a high-temperature gaseous coolant with an aqueous solution of lithium chloride. In this case, there is an intensive evaporation of water in the lithium chloride solution, accompanied by forced cooling of the gaseous coolant with its saturation with water vapor and enrichment of the solution in lithium chloride, i.e. its concentration.

The initial solution from the tank (31) is fed by a pump (32) to the recovery heat exchanger (33), where it is heated by utilizing the residual heat from the steam-gas mixture, cooling it to 50-80 °C. The heated solution is sprayed in the flue gas flow inside the column, which is part of the evaporation unit (34) through spray devices, including those located on the walls of the evaporation unit column. As a result of the contact of solution droplets with the flue gas, which has a temperature of 400 to 800 °C, water evaporates from the solution, while the temperature of the flue gas decreases, while as a result of removing water from the solution, the concentration of salts increases, when the concentration of the resulting concentrated solution for lithium chloride reaches 430 g / dm ³ or more, the chlorides of sodium, potassium, magnesium and calcium actively pass into a supersaturated state, a solid phase of the above salts is formed, which settles to the bottom of the circulation tank - thickener of the evaporation unit, located below the column of the evaporation unit. A suspension is formed, the liquid phase of which consists of a lithium chloride solution, with a high temperature depression, as a result of which the boiling point of the solvent also increases. When the temperature of the suspension and flue gas reaches about 78-120°C, thermodynamic equilibrium occurs; further evaporation of water from the suspension does not occur. This effect ensures that the suspension leaves the evaporation unit (34) with a strictly specified concentration of lithium chloride. The suspension from the evaporation unit is pumped from below by a pump (35) to the centrifuge (36) for separation, from where the crystalline precipitate of salts is fed into transport containers (37). The centrate - a solution of lithium chloride from the centrifuge (36) enters the centrate collection tank (38), from where it is removed outside the unit by a pump (39) through a recovery heat exchanger (40). If it is necessary to increase the concentration of lithium chloride in the concentrated solution (to bring the unit to the mode with the required concentration of the solution), a line is provided for returning a portion of the solution for spraying in the column included in the evaporation unit (34). The steam-gas mixture from the evaporation unit (34) enters the recovery heat exchanger (3), where it is cooled due to heat exchange with the initial solution. The resulting condensate is removed from the system. Next, the steam-gas mixture is fed to the moisture separation system (41), and the condensate is also removed from this system. For reuse, part of the flue gas after the moisture separation system (41) can be sent to the heat generator, and the other part is discharged outside the plant. Flue gas is prepared in the heat generator (42) by burning associated petroleum gas.

Example 3.

The scheme of the installation for obtaining lithium chloride monohydrate is shown in Fig. 3.

The installation for obtaining lithium chloride monohydrate provides preliminary purification, concentration of lithium chloride solution and the process of further evaporation of the concentrate with the isolation and washing of lithium chloride monohydrate crystals, the part of the installation responsible for concentrating the lithium chloride solution is similar to that described in Example 1 (Fig. 1), but it can also be the installation described in Example 2 (Fig. 2).

The product concentrate from the productive lithium concentrate receiving tank (19) is pumped by (43) into the lithium chloride monohydrate precipitation evaporation column (44), where the concentrate is heated with a heat carrier (heating steam) to form lithium chloride monohydrate crystals. The suspension containing lithium chloride monohydrate is sent from the lithium chloride monohydrate precipitation column (44) to the first centrifuge (45), the centrate from the first centrifuge (45) is returned to the lithium chloride monohydrate precipitation column (44). The cake from the first centrifuge (45) is discharged into the first stirred reactor (46), water is added to the first stirred reactor (46) from the water tank (49) through the water feed pump (50), the mixture is pulped in the first reactor (46) until pulp is obtained, the pulp is pumped into the second centrifuge (47) by means of a transfer pump (53). The pulp is centrifuged in the second centrifuge (47) with the cake being discharged into the second reactor with a stirrer (48) and the fugate being pumped through the heat exchanger-condenser (14) into the source of the initial solution (8); during the process of pumping the fugate through the heat exchanger-condenser (14), the fugate is heated. Water is added to the cake discharged into the second reactor with a stirrer (48) from the water tank (49) via the water feed pump (50) and the pulp is depulped, the resulting pulp is pumped by the pumping pump (53) into the second centrifuge (47), the pulp is centrifuged in the second centrifuge (47) with the cake discharged into the second reactor with a stirrer (48) and the fugate is pumped through the heat exchanger-condenser (14) into the source of the initial solution (8), during the process of pumping the fugate through the heat exchanger-condenser (14) it is heated. Water is added to the cake discharged into the second reactor with a stirrer (48) from the water tank (49) via the water feed pump (50) and the pulp is depulped, the resulting pulp is pumped by the pumping pump (53) into the second centrifuge (47), the pulp is centrifuged in the second centrifuge (47) with the discharge of the washed lithium chloride monohydrate crystals into the product collection tank (51) and the centrate is pumped through the heat exchanger-condenser (14) into the source of the initial solution (8), while the centrate is pumped through the heat exchanger-condenser (14), it is heated. Steam from the evaporation column for the precipitation of lithium chloride monohydrate (44) is sent to the heat exchanger (52), where heat exchange, condensate formation and condensate removal occur, the spent and cooled coolant is blown into the atmosphere.

Sources of information used

1. Patent. RF No. 2283283. IPC C01D 15/08. Method for obtaining high-purity lithium carbonate from lithium-bearing chloride brines / V.I. Titarenko, A.D. Ryabtsev, N.P. Kotsupalo, L.T. Menzheres, A.A. Kurakov, E.P. Gushchina. Application dated December 30, 2004, publ. 09/10/2006. Bull. No. 25.

2. Pat. CN 105540619 B. IPC C01D15/08. A kind of preparation method of battery-level lithium carbonate I Wen Xianming, Zhu Chaoliang, Deng Xiaochuan, Duan Dongping, Ma Peihua, Shao Fei, Guo Xiaoying, Shi Fei, Shi Yifei, Qing Bingju , Fan Faying, Wang Yan'an. Application dated July 22, 2016, pub. 12/15/2017.

3. Zbrodin N.I., Nechaeva A.A., Korobochkina T.V. Content of rare alkaline elements in salt raw materials of the Soviet Union and prospects for their industrial development / Rare alkaline elements. - Novosibirsk: Siberian Branch of the USSR Academy of Sciences, 1960. pp. 97-100.

4. Application WO 2016064689 A2 (WIPO). IPC B01D61/58. Forward osmosis process for concentration of lithium containing solutions I Ackson R. Switzer, Neal J. Colonius, Chi Hung Cheng, Pieter Johannes Daudey. Application dated October 16, 2015, pub. 04/28/2016.

5. Pat. US 10505178 B2. MPK N01M4/131. Ion exchange system for lithium extraction / David Henry Snydacker, Alexander John Grant, Ryan Ali Zarkesh. Application dated May 10, 2019, pub. 12/10/2019.

6. Patent. USSR No. 1680634. IPC C02F 1/12, C02F 103/02. Method for evaporating mineralized waters / A. Yu. Dykhno, A. A. Areshkin, K. A. Arutyunov, S. V. Gorbatenko, K. A. Bragina. Application dated 02.12.1986, published 30.09.1991.

7. Pat. US 2327039 A. IPC B01D1/16. Spray evaporator / Sheldon In Heath. Application dated July 10, 1941, pub. 08/17/1943.

8. Pat. US 2640762 A. IPC C01D5/18. Process for evaporating sodium sulfate solutions and recovering sodium sulfate therefrom / James V Wiseman. Application dated November 25, 1949, pub. 06/02/1953. 9. Pat. US 11390791 B2. IPC S09K8/04. Apparatus for concentrating wastewater and for creating brines / Bernard F. Duesel, Jr. Michael J. Rutsch, Craig Clerkin. Application dated March 16, 2021, pub. 07/19/2022.

Claims

Invention formula 1. A method for concentrating a lithium chloride solution by evaporating a portion of the water from a liquid, characterized in that a lithium-containing medium is used as the initial solution for concentration; a stream of hot gas obtained using a gas heat generator is used as the heat carrier; water is evaporated in an evaporation unit, which is a column combined with a circulating thickening tank, with liquid spraying from top to bottom in the flow of the heat carrier; an operating mode of the evaporation unit is used in which the concentration of the resulting concentrated solution for lithium chloride is brought to 430 g/dm ³ or more, which ensures the salting out of impurity salts while maintaining lithium chloride in a dissolved state and obtaining a product concentrate; impurities falling out of the evaporated lithium chloride solution are deposited in the circulating thickening tank of the evaporation unit, located below the column of the evaporation unit, and are separated from the solution by centrifugation; The steam-gas mixture obtained after contact with the solution is removed from the evaporation unit through a heat exchanger, returning part of the thermal energy to the system. 2. The method according to item 1, characterized in that additional evaporation of water is carried out from the surface of the solution in the circulation tank-thickener of the evaporation unit. 3. The method according to claim 1, characterized in that the medium containing lithium is a brine of natural origin. 4. The method according to claim 1, characterized in that the medium containing lithium is a solution after a reverse osmosis filtration operation in the technology of extracting lithium from natural brines. 5. The method according to claim 1, characterized in that the medium containing lithium is a solution after a brine nanofiltration operation. 6. The method according to claim 1, characterized in that the medium containing lithium is a primary lithium concentrate, which is obtained using the DGAL-S1 sorbent. 7. The method according to paragraph 1, characterized in that the fuel for the gas heat generator is gas produced along with oil. 8. The method according to paragraph 1, characterized in that the portion of thermal energy returned to the system is spent on heating the initial solution. 9. The method according to claim 1, characterized in that in order to implement the evaporation process in a continuous, steady-state mode, part of the lithium chloride solution freed from impurities and concentrated as a result of evaporation is removed as a product concentrate, and part, after mixing with the flow of the initial solution supplied for evaporation as a medium containing lithium, is returned to the evaporation stage. 10. The method according to paragraph 9, characterized in that the product concentrate is removed from the system through a heat exchanger with the return of part of the thermal energy to the system. I. The method according to paragraph 10, characterized in that thermal energy is used to heat the air entering the heat generator. 12. The method according to item 9, characterized in that the solution returned to the evaporation stage is passed through a filter. 13. The method according to paragraph 1, characterized in that during the passage of the steam-gas mixture through the heat exchanger, which was formed by contact between the heat carrier and the solution, condensate is formed, which is collected and removed from the system. 14. The method according to item 1, characterized in that the evaporation unit column uses trays with holes. 15. The method according to item 1, characterized in that the hot gas is fed into the column of the evaporation unit from the bottom up. 16. The method according to item 15, characterized in that the temperature of the gas at the outlet of the evaporation unit column does not exceed 100°C. 17. The method according to item 15, characterized in that when the coolant is cooled to a temperature below the dew point temperature, hot gas is additionally supplied to the upper part of the evaporation unit column to increase the temperature. 18. The method according to item 15, characterized in that before being fed into the column of the evaporation unit, the hot gas flows around the surface of the solution in the circulation thickening tank of the evaporation unit. 19. The method according to item 15, characterized in that the hot gas is supplied to the evaporation unit at a temperature from 400°C to 800°C. 20. The method according to paragraph 1, characterized in that air is additionally mixed into the coolant to regulate the temperature and volume of the coolant. 21. The method according to 11.20, characterized in that air is mixed in a vortex mixer. 22. The method according to paragraph 1, characterized in that a cyclone-type gas heat generator is used. 23. The method according to paragraph 1, characterized in that the selection of the lithium chloride product concentrate is carried out from the circulation thickener tank of the evaporation unit. 24. The method according to paragraph 1, characterized in that the vapor-gas mixture obtained after contact of the heat carrier with the solution is directed to a drip collector with the collected liquid being discharged into the circulation thickening tank of the evaporation unit. 25. The method according to paragraph 1, characterized in that the vapor-gas mixture obtained after contact of the heat carrier with the solution is directed to a drip collector with the collected liquid being discharged into the original solution. 26. The method according to claim 1, characterized in that in order to accelerate the salting out of impurities, the circulation thickening tank of the evaporation unit is additionally cooled. 27. The method according to claim 1, characterized in that after centrifugation of the precipitated impurities, they are washed in the following order: the cake is discharged into the first reactor with a stirrer; a portion of the washing liquid from the first container with the washing liquid is introduced into the first reactor with a stirrer and pulped; the resulting suspension is sent for centrifugation; the centrate is returned to the evaporation unit, the cake is discharged into the second reactor with a stirrer; a portion of the washing liquid from the second container with the washing liquid is introduced into the second reactor with a stirrer and pulped; the resulting suspension is sent for centrifugation; the centrate is sent to the first container with the washing liquid, the cake is discharged into the second reactor with a stirrer; a portion of fresh water is introduced into the second reactor with a stirrer and pulped; the resulting suspension is sent for centrifugation; The centrate is sent to the second container with washing liquid, and the cake is unloaded. 28. The method according to paragraph 27, characterized in that the fresh water used is condensate obtained by cooling the discharged steam-gas mixture, which was formed by contact between the heat carrier and the solution. 29. The method according to item 1, characterized in that the heat exchanger is additionally cooled using a cooling tower. 30. The method according to paragraph 1, characterized in that the hot gas is fed into the column of the evaporation unit from top to bottom. 31. The method according to paragraph 30, characterized in that the hot gas is fed into the column of the evaporation unit at a temperature of 400°C to 800°C and at the outlet of the column of the evaporation unit the steam-gas mixture has a temperature of 78°C to 120°C. 32. The method according to paragraph 1, characterized in that part of the exhaust gas mixture is directed to the heat generator. 33. The method according to claim 1, characterized in that the selection of the product lithium chloride concentrate is carried out from the centrate after the centrifugation operation. 34. A device for concentrating a lithium chloride solution by evaporating a portion of the water from a liquid, comprising a gas inlet; an evaporation unit, which is a column combined with a circulating thickening tank, with an injection system for injecting the liquid to be concentrated; a recirculation loop connecting the circulating thickening tank of the evaporation unit and the column of the evaporation unit; a gas outlet, characterized in that a gas heat generator is installed in front of the gas inlet; the column of the evaporation unit is designed as a cylindrical vertical column; the system for injecting the liquid to be concentrated into the column of the evaporation unit is located in the upper part of the column of the evaporation unit and is designed as one or more sprayers located in the internal volume of the column of the evaporation unit, or located on the body of the column of the evaporation unit, ensuring direct contact of the liquid and gas; the circulation tank-thickener of the evaporation unit is located below the column of the evaporation unit and has a narrowing in the lower part; the lower part of the circulation tank-thickener of the evaporation unit is connected to the centrifuge, and there is a channel for returning the separated liquid phase after centrifugation to the evaporation unit; after the outlet for gas, a heat exchanger with a condensate collection system is installed, providing heating of the initial solution. 35. The device according to item 34, characterized in that a filter is installed in the recirculation circuit connecting the circulation thickening tank of the evaporation unit and the column of the evaporation unit. 36. The device according to item 34, characterized in that trays with holes are installed in the column of the evaporation unit. 37. The device according to item 34, characterized in that the gas inlet is located so that the gas is fed into the evaporation unit column from the bottom up. 38. The device according to item 34, characterized in that after the gas heat generator a channel is installed for additional mixing of air into the heat carrier. 39. The device according to item 34, characterized in that after the gas heat generator a vortex mixer is installed for additional mixing of air into the heat carrier. 40. The device according to item 34, characterized in that the gas heat generator is made according to a cyclone scheme. 41. The device according to item 34, characterized in that after the gas outlet, a drip collector is installed with a channel that ensures the discharge of the captured liquid into the circulation thickening tank of the evaporation unit. 42. The device according to item 34, characterized in that the circulation thickening tank of the evaporation unit has a channel for collecting the product lithium chloride concentrate. 43. The device according to item 42, characterized in that a heat exchanger is installed on the channel for collecting the lithium chloride product concentrate, which collects heat from the product concentrate, and there is also an air blower that directs the cooled portion of the exhaust gas mixture into a gas heat generator. 44. The device according to item 42, characterized in that the line for removing the centrifuge fugate is connected to a channel for collecting the lithium chloride product concentrate. 45. The device according to item 34, characterized in that after the gas outlet, a drip collector is installed with a channel that ensures the removal of the captured liquid into the original solution. 46. The device according to 11.34, characterized in that the circulation thickening tank of the evaporation unit is equipped with a cooler. 47. The device according to item 34, characterized in that the centrifuge for separating impurities is connected to a reactor equipped with a stirrer, the reactor in turn is connected to a line for removing pulp and to a container containing a washing solution; the line for removing pulp is connected to a second centrifuge, the second centrifuge is connected to a circulation thickener tank of the evaporation unit, to a channel for unloading cake, to a container containing a washing solution and to a second reactor equipped with a stirrer, the second reactor equipped with a stirrer is connected to the inlet of the second centrifuge. 48. The device according to item 34, characterized in that a cooling tower is installed for additional cooling of the heat exchanger. 49. The device according to item 34, characterized in that the gas inlet is located so that the gas is fed into the evaporation unit column from top to bottom. 50. A method for producing lithium chloride monohydrate, characterized in that at the first stage, a lithium chloride solution is concentrated by evaporating a portion of the water from the liquid using the method of claim 1, and then the resulting concentrate is evaporated with heating steam until a suspension containing lithium chloride monohydrate crystals is formed; the suspension is centrifuged, the resulting cake is returned to the stage of producing the concentrate, and the cake is washed with water and the suspension obtained after washing is sent for centrifugation; after centrifugation, the cake in the form of lithium chloride monohydrate crystals is discharged. 51. The method according to item 50, characterized in that the steam obtained during the evaporation of the lithium chloride concentrate is sent for condensation with the removal of condensate. 52. The method according to item 50, characterized in that the washing of the cake with water is carried out in three stages, in the first stage of washing the cake is pulped with the addition of water and the resulting pulp is sent for centrifugation, the cake is sent to the second stage of washing, and the centrate is mixed into the initial lithium-containing solution for concentration, in the second stage of washing the cake is pulped with the addition of water and the resulting pulp is sent for centrifugation, the cake is sent to the third stage of washing, and the centrate is mixed into the initial lithium-containing solution for concentration, in the third stage the cake is pulped with the addition of water and a suspension is obtained. 53. The method according to paragraph 52, characterized in that the centrate mixed into the initial solution is preheated due to the residual heat of the steam-gas mixture that was formed by contact between the heat carrier and the solution. 54. A device for producing lithium chloride monohydrate, characterized in that it comprises a device for concentrating a lithium chloride solution by evaporating a portion of the water from the liquid according to claim 34, connected to a product concentrate receiving line that supplies the product concentrate to an evaporation column for precipitating lithium chloride monohydrate; the evaporation column for precipitating lithium chloride monohydrate has a channel for removing condensate at the bottom, a channel for inlet of a heat carrier, a channel for outlet of moisture-saturated steam, a channel for removing a suspension containing lithium chloride monohydrate crystals; the channel for outlet of moisture-saturated steam is connected to a heat exchanger; the channel for removing the suspension containing lithium chloride monohydrate crystals is connected to a first centrifuge that has a centrate return channel and a cake discharge channel; a centrate return channel is connected to an evaporation column for precipitation of lithium chloride monohydrate; the cake discharge channel is connected to a depulping reactor equipped with a stirrer; the depulping reactor is connected to a second centrifuge and to a washing liquid feed line; the second centrifuge is connected to a container with an initial lithium-containing solution for directing the centrate into it and to a second depulping reactor equipped with a stirrer; the second centrifuge is connected to a lithium chloride monohydrate discharge channel.