Method for obtaining calcium chloride from calcium chloride-type brines

Abstract

The present invention relates to the field of chemical technology for the recovery of salts from brines, and more particularly to the recovery of calcium chloride from calcium chloride-type brines by evaporation. The invention can be used for the separation of multiple salts during the industrial treatment of brines to obtain calcium chloride, carnallite, potassium chloride and sodium chloride. The present method consists in successively evaporating a brine to remove impurities by salt fractionation and to obtain a target product. The characterizing features of the method according to the present invention make it possible to reduce calcium chloride loss, to save heat energy by using process steam, to increase the purity of the product obtained and to use calcium-chloride-type brines containing impurities in the form of potassium, sodium and magnesium as feedstock.

Description

[0001] METHOD OF OBTAINING CALCIUM CHLORIDE FROM CALCIUM CHLORIDE BRINES

[0002] Field of technology.

[0003] The invention relates to the field of chemical technology for extracting salts from brines, in particular to extracting calcium chloride from calcium chloride brines by evaporation. The invention can be used for complex separation of salts during industrial processing of brines to obtain calcium chloride, carnallite, potassium chloride and sodium chloride.

[0004] State of the art.

[0005] A method for producing calcium chloride is known according to patent RU2291109C2 [1] “Method for producing calcium chloride”, which includes the interaction of calcium-containing raw materials with hydrochloric acid at a temperature of 20-50°C, characterized in that 20-37% hydrochloric acid is dosed to the calcium-containing raw materials at a molar ratio of CaCO3: HCl = 1:2, followed by passing the resulting acidic CaCE solution through CaCO3 and the resulting acidic carbon dioxide through CaCO3 and CaCE, taken in a molar ratio of 1-4:1.

[0006] The disadvantage of this method is the need to use pure calcium carbonate as raw material, as well as the need to use a reagent in the form of hydrochloric acid, the use of such pure products is expensive, the method is not intended for obtaining calcium chloride from natural sources of calcium, such as calcium chloride brines.

[0007] A calcium chloride production plant is known from the prior art according to patent RU25502U1 [2] "Plant for producing calcium chloride", in which the process of producing calcium chloride is carried out by mixing the starting materials: potassium chloride, calcium nitrate and water, while it is possible to mix in the double salt KNO3 CaCeH2O (coming from the filtration process), after preparing a solution from the starting materials, the solution is fed for cooling, as a result of which potassium nitrate is released, which is separated and sent for drying to obtain a product in the form of potassium nitrate, and the solution after separating the potassium nitrate is fed to an evaporator, where the solution is evaporated, after which the concentrate is fed for cooling and purification from the solid phase in a filter-sedimenter, while the double salt KNO3 CaCeH2O is separated, and the mother liquor is fed to the calcium chloride extraction unit, then the product is fed to the granulator-dryer and to the product packaging unit.

[0008] The disadvantage of the described method is the need to use potassium chloride, calcium nitrate and water as raw materials, the presented scheme is also complex and requires a cooling unit, the method is not intended for obtaining calcium chloride from natural calcium sources, such as calcium chloride brines.

[0009] The process of obtaining salts from hydromineral raw materials with their separation in the process of evaporation is widely known, for example, the method is known according to patent US3536444A [3] "Method for separating brine components", in which the separation and extraction of brine components containing sodium, potassium, magnesium, chloride and sulfate ions is carried out, whereby NaCl is first salted out by evaporation, which is separated from the solution, the resulting solution is mixed with a solution of MgCl and the following evaporation is carried out with the precipitation of KCl-MgCl-6H2O, the solid phase is separated, the liquid phase is subjected to evaporation for the crystallization of magnesium sulfate hydrates and the production of a third solution, the third solution is used as a solution of MgCh at the stage of isolating KCl-MgCl-6H2O.

[0010] The disadvantage of this method is that it cannot be used to obtain calcium chloride and requires additional addition of magnesium chloride solution. The brine used in the method does not contain calcium chloride.

[0011] A method is known according to patent US4224037A [4] “Method for operating multi-effect evaporators”, in which the separation of salts with different degrees of solubility is carried out by evaporation, in particular the method is considered for salts whose solubility increases with increasing temperature (the first salt), such as potassium chloride, magnesium chloride, sodium carbonate, sodium chlorate and salts whose solubility slightly increases or decreases with increasing temperature (the second salt), such as sodium chloride, calcium sulfate and magnesium sulfate.

[0012] When extracting the first salt from an aqueous solution containing the first salt and the second salt, water is removed from the solution by multiple step evaporation in a multi-step evaporator, wherein the initial solution is fed to the last step of the evaporator, and the initial steam to the first step of the evaporator, the first step of the evaporator is the hottest, the steam obtained by evaporation in a hotter step is directed to a colder step, while the concentrated solution flows from the colder step to the hotter step, i.e. moves from the last step to the first step of the evaporator. At each step, the precipitate that falls out is separated in the form of the second salt, and the drain flow of the mother liquor from the first step is used to obtain the first salt.

[0013] A similar method is described in patent US4224035A [5] “Method for separating salts from a solution”.

[0014] The presented method is the closest to the proposed method of the present invention.

[0015] The disadvantage of the method is the use of overflow or conventional pumping of the concentrate (mother liquor) between the evaporator stages, which requires the use of a large number of stages for effective separation of the mother liquor from impurities. The disadvantage of the method is the need to carry out a separate operation for processing the concentrate to obtain the target product. The disadvantage of the method is the use of a large number of stages for evaporation, which complicates the production, maintenance and use of the plant. The disadvantage of the method is the lack of operations for processing salt sediments that fall out during the processing of hydromineral raw materials containing calcium, magnesium, sodium and potassium. The method does not provide for complex separation of salts for calcium chloride brines containing potassium, magnesium and sodium chlorides as impurities.

[0016] The proposed method according to the proposed invention does not contain the indicated disadvantages and is suitable for the complex separation of salts and the production of calcium chloride from calcium chloride-type brines containing impurities of magnesium, sodium and potassium.

[0017] The essence of the invention.

[0018] The aim of the present invention is the comprehensive separation of salts during the processing of calcium chloride brines of natural and industrial origin, containing magnesium, potassium and sodium as impurities, with the production of calcium chloride.

[0019] The proposed method allows obtaining products in the form of calcium chloride crystal hydrate or calcined calcium chloride from calcium chloride-type brines by evaporation without the use of reagents and using a minimum number of evaporation apparatuses.

[0020] The proposed method allows obtaining carnallite, potassium chloride and sodium chloride as by-products of processing the said brines.

[0021] The proposed method ensures complete complex processing of brines with the extraction of components suitable for further industrial use.

[0022] The proposed method ensures efficient use of thermal energy by using secondary steam.

[0023] The proposed method ensures a reduction in calcium chloride losses during its production.

[0024] The technical result of implementing the method is the effective use of calcium chloride-type brines containing magnesium, potassium and sodium impurities as a source of calcium chloride, simplifying the design of the evaporation unit, obtaining valuable by-products from processing brines, and directly obtaining calcium chloride crystal hydrate. The technical result is achieved by evaporating the initial brine in an evaporation unit that includes at least two evaporation apparatuses, wherein the primary evaporation of the brine is carried out in the second evaporation apparatus due to the secondary steam obtained in the first evaporation apparatus, and the secondary evaporation is carried out by the initial steam in the first evaporation apparatus, as a result of which a secondary steam with a temperature lower than the initial steam is formed, wherein the initial brine is a calcium chloride-type brine containing calcium chloride in an amount of more than 60% by weight,in relation to impurities of other chlorides - sodium, potassium, magnesium, during evaporation of the initial brine in the second evaporator, with an increase in the concentration of salts in the brine, predominantly sodium, potassium and magnesium chloride salts crystallize, which are separated in the second separator to obtain a solid phase and calcium chloride concentrate, the calcium chloride concentrate is sent for evaporation in the first evaporator, where it is concentrated with the precipitation of calcium chloride, the precipitate is separated from the steam in the first separator to obtain calcium chloride crystal hydrate; the solid phase separated after the primary evaporation and containing predominantly sodium, potassium and magnesium chlorides can be sent for step washing with the dissolution of magnesium chloride first, then potassium chloride and subsequent separation of the crystalline material from the mother liquor, while hot water is used to dissolve the potassium chloride,potassium chloride is separated from the solution by cooling; for processing the solid phase separated after the primary evaporation and containing predominantly sodium, potassium and magnesium, it can be dissolved and used in the process of obtaining carnallite, wherein the process of obtaining carnallite is carried out by evaporation in two stages, in the first stage steam with a lower temperature is used than for evaporation in the second stage, in the first stage of evaporation mainly sodium chloride precipitates, the resulting mother liquor is sent to the second stage of evaporation, where during evaporation mainly carnallite precipitates, which is separated; in the first stage of the process of obtaining carnallite it is possible to use steam that was obtained by evaporation of the mother liquor in the second stage of the process of obtaining carnallite; in the first stage of the process of obtaining carnallite it is possible to use steam,which was obtained in the first evaporator in the process of obtaining calcium chloride crystal hydrate; the precipitate after the primary evaporation, containing predominantly sodium, potassium and magnesium, can be dissolved in water to obtain a saturated solution; the separated carnallite can be used to obtain magnesium or potassium chloride; at least one separator for separating the liquid and solid phases can be made in the form of a settler, centrifuge or belt filter; after separating the liquid and solid phases in at least one separator, the solid phase can be additionally separated from the liquid in a centrifuge or belt filter; the obtained calcium chloride crystal hydrate can be used to obtain calcined calcium chloride.

[0025] The technical result is achieved by the fact that during the primary evaporation of calcium chloride brine containing sodium, magnesium and potassium impurities, precipitation of sodium, potassium and magnesium chloride salts occurs, which ensures the production of calcium chloride concentrate for the further production of calcium chloride crystal hydrate in one operation, while the use of secondary steam provides the necessary temperature conditions for evaporation and savings in thermal energy, since it is reused in the process.

[0026] The technical result is achieved by the fact that during secondary evaporation, the initial steam with the greatest energy is used, which allows for the most complete removal of water from the calcium chloride concentrate to obtain calcium chloride crystal hydrate, while the calcium chloride crystal hydrate and steam are separated, obtaining the target product and heat carrier (steam) for primary evaporation within the framework of secondary evaporation.

[0027] The technical result is achieved by the fact that the chloride salts of sodium, potassium and magnesium, released during primary evaporation, are separated in a separator to obtain a solid phase and a calcium chloride concentrate, which is then fed to secondary evaporation, this ensures effective and rapid separation of the phases, which prevents the ingress of impurity crystals into the calcium chloride concentrate, contaminating the final product, and also allows for a reduction in calcium chloride losses during sediment removal.

[0028] The technical result is achieved by the fact that the initial brine is a calcium chloride type brine containing calcium chloride in an amount of more than 60% by weight, in relation to impurities of other chlorides - sodium, potassium, magnesium, the choice of such initial raw material ensures the effective separation of impurities during evaporation of the brine and an effective yield of calcium chloride crystal hydrate.

[0029] The technical result is achieved by the fact that the solid phase separated after the primary evaporation, containing mainly sodium, potassium and magnesium, can be sent to a step-by-step washing with the dissolution of magnesium chloride first, then potassium chloride and the subsequent separation of the crystalline material from the mother liquor, while hot water is used to dissolve the potassium chloride, potassium chloride is isolated from the solution by cooling. Obtaining potassium chloride as a by-product of processing calcium chloride brine increases the economic effect of using the method.

[0030] The technical result is achieved in that the solid phase separated after the primary evaporation, containing predominantly sodium, potassium and magnesium, is dissolved and used in the process of obtaining carnallite, the process of obtaining carnallite is carried out by evaporation in two stages, in the first stage steam with a lower temperature is used than for evaporation in the second stage, in the first stage of evaporation mainly sodium chloride precipitates, the obtained mother liquor is sent to the second stage of evaporation, where the solution is evaporated until predominantly carnallite precipitates, which is separated, this process allows obtaining carnallite as a by-product of processing calcium chloride brine, which increases the economic effect of using the method.

[0031] The technical result is achieved by using steam at the first stage of the process of obtaining carnallite, which was obtained by evaporating the mother liquor at the second stage of the process of obtaining carnallite, or in the first evaporator during the process of obtaining calcium chloride crystal hydrate, which provides the necessary temperature conditions for evaporation and savings in thermal energy, since it is reused in the process.

[0032] The technical result is achieved by the fact that the solid phase separated after the primary evaporation, containing predominantly sodium, potassium and magnesium, is dissolved in water to obtain a saturated solution, which reduces energy costs and simplifies further evaporation of the solution in the process of obtaining carnallite.

[0033] The technical result is achieved by the fact that separators can be made in the form of a centrifuge or a belt filter, which improves the quality of phase separation.

[0034] The technical result is achieved by the fact that after separators, the liquid and solid phases can be additionally separated in a centrifuge or belt filter, which improves the quality of phase separation.

[0035] The technical result is achieved in that the obtained crystal hydrate can serve as raw material for obtaining calcined calcium chloride.

[0036] The technical result is achieved in that the obtained crystal hydrate can serve as raw material for obtaining calcined calcium chloride.

[0037] In its most general form, the method of the present invention can be implemented as follows, but is not limited thereto.

[0038] The flow chart of the method is shown in Fig. 1, the initial calcium chloride brine containing calcium chloride in an amount of more than 60% by weight, in relation to impurities of other chlorides - sodium, potassium, magnesium, is sent to the second evaporator (4), wherein the brine can be preheated in the heat exchanger (7) due to the residual heat of the secondary steam (an optional process), in the second evaporator (4) the brine is evaporated due to the secondary steam with the precipitation of a precipitate in the form of potassium, magnesium and sodium salts, which are separated in the second separator (5) and sent to the sediment receiver (6), the separated liquid phase in the form of calcium chloride concentrate is sent to the first evaporator (1), where evaporation is carried out due to the initial steam, the concentrate is evaporated with the production of calcium chloride crystal hydrate and secondary steam, which are separated in the first separator (2), the calcium chloride crystal hydrate is sent to the product receiver (3),and the secondary steam is sent to the second evaporator (4), from where the spent secondary steam enters the heat exchanger (7), the condensate is sent to the condensate collection tank (8).,

[0039] The obtained calcium chloride crystal hydrate can be processed into calcined calcium chloride, for example, by drying in a drying oven.

[0040] The method according to the present invention, also including the production of carnallite, is shown in Fig. 2, the initial calcium chloride brine containing calcium chloride in an amount of more than 60% by weight, relative to impurities of other chlorides - sodium, potassium, magnesium, is sent to the second evaporator (4), wherein the brine can be preheated in the heat exchanger (7) due to the residual heat of the secondary steam, in the second evaporator (4) the brine is evaporated due to the secondary steam with the precipitation of a precipitate in the form of potassium, magnesium and sodium salts, which are separated in the second separator (5) and sent to the sediment receiver (6), the separated liquid phase in the form of calcium chloride concentrate is sent to the first evaporator (1), where evaporation is carried out due to the initial steam, the concentrate is evaporated with the production of calcium chloride crystal hydrate and secondary steam, which are separated in the first separator (2), the calcium chloride crystal hydrate is sent to the product receiver (3),and the secondary steam is sent to the second evaporator (4), from where the spent secondary steam enters the heat exchanger (7), the condensate is sent to the condensate collection tank (8), the salt impurities from the sediment receiver (6) are sent to the salt dissolution station (9), where the salts are dissolved in water, the condensate obtained during the cooling of the steam can be used to dissolve the salts, it is preferable to dissolve the salts until a saturated solution is obtained, the obtained solution of potassium, sodium and magnesium chlorides from the salt dissolution station is sent to the evaporator of the first stage of obtaining carnallite (10), where during evaporation mainly sodium chloride precipitates, which is separated in the third separator (11) and sent to the sodium chloride receiver (12), the liquid phase in the form of a solution of potassium and magnesium chloride enters the evaporator of the second stage of obtaining carnallite (13), where it is evaporated to obtain carnallite,which is separated from the steam in the fourth separator (14) and sent to the carnallite receiver (15), the separated steam can be used for evaporation in the first stage evaporator (10), and steam from the second evaporator (4) can also be used for evaporation in the first stage evaporator (10).

[0041] Carnallite can then be used to produce magnesium or potassium chloride by any suitable industrial method.

[0042] As part of the implementation of the method, additional heat exchangers can be used to preheat the solutions with residual heat from the steam.

[0043] As an alternative variant for processing the solid phase separated after the primary evaporation and containing predominantly sodium, potassium and magnesium, it is possible to obtain potassium chloride by the following process: the crystalline precipitate is sent for washing with the dissolution of magnesium chloride, then the washed crystalline material is separated from the liquid, the potassium chloride contained in said crystalline material is dissolved with a hot solvent to form a hot saturated solution of potassium chloride, said solution saturated with potassium is separated from undissolved solids in a hot state, said solution saturated with potassium is cooled and the potassium chloride is separated from the cooled mother liquor.

[0044] Below are examples of implementation of the method according to the present invention.

[0045] Example 1.

[0046] The raw material used to obtain calcium chloride was a calcium chloride brine containing: Ca - 131 g / l, Na - 8.1 g / l, Mg - 16.2 g / l, K - 20 g / l.

[0047] According to the diagram shown in Fig. 1 and the above description of the process, primary evaporation was carried out in the second evaporator (4) of the brine preheated in the heat exchanger (7), and secondary evaporation was carried out in the first evaporator (1), while during the primary evaporation a solid precipitate and a calcium chloride concentrate were obtained, which were separated in the second separator (5), directing the hot suspension there, the calcium chloride concentrate contained impurities in the amount of: Na - up to 2 g / l, Mg - up to 10 g / l, K - up to 5 g / l.

[0048] The calcium chloride concentrate was evaporated in the first evaporator (1) and the steam and solids were separated in the first separator (2). As a result of the separation, a product was obtained containing 92% by weight of calcium chloride crystal hydrate and steam; the steam was sent as secondary steam to the second evaporator (4).

[0049] Example 2

[0050] The process of obtaining calcium chloride crystal hydrate was carried out similarly to Example No. 1, with the difference that a calcium chloride brine was used, containing: Ca - 91.59 g / l, Na - 7.2 g / l, Mg - 12.4 g / l, K - 17.1 g / l.

[0051] The calcium chloride concentrate contained impurities in the following quantities: Na - 1 g / l, Mg - 5 g / l, K - 4 g / l.

[0052] As a result of secondary evaporation and separation, a product containing 90% by weight of calcium chloride crystal hydrate was obtained.

[0053] It was found that when the concentration of calcium chloride in the brine is less than 60% by weight, in relation to impurities of other chlorides - sodium, potassium and magnesium, the efficiency of the method is significantly reduced.

[0054] Example 3.

[0055] The process of obtaining calcium chloride crystal hydrate was carried out similarly to Example No. 1 with the difference that the obtained sediment (solid phase) was sent to the stage of primary washing with water by displacement on a belt vacuum filter. The residual content of calcium chloride in the crystallizate did not exceed 1.1%. After the stage of primary washing, the crystallizate was sent to the stage of cold decomposition, where it was washed for 1 minute by dilution in a reactor from magnesium chloride and calcium chloride with water at a temperature of 10°C. The resulting suspension was separated on the filter. The wet precipitate after filtration was sent to the hot dissolution stage, where at a temperature of 97°C it was treated with hot water, the precipitate remaining after dissolution of potassium chloride was separated from the solution saturated with potassium chloride on a vacuum filter, the saturated solution of potassium chloride was cooled to 22°C to obtain a secondary crystalline product with a concentration of KCl of at least 95%.The obtained crystalline product KC1 was washed with fresh water in an amount of 10% of the mass of the wet product, obtaining a crystallizate with a concentration of KC1> 95%.

[0056] Example 4.

[0057] The process of obtaining calcium chloride crystal hydrate was carried out similarly to Example No. 1, with the difference that carnallite was also obtained according to the scheme shown in Fig. 2 and described above.

[0058] The salt impurities from the sediment receiver (6) were sent to the salt dissolution station (9), water and condensate from the condensate collection tank (8) were used to dissolve the salts, a saturated solution of potassium, sodium and magnesium chlorides was obtained at the salt dissolution station, the solution contained: Na - 21 g / l, Mg - 40.2 g / l, K - 65 g / l, Ca - 1 g / l.

[0059] The solution was sent for evaporation to the first stage evaporator for obtaining carnallite (10), where predominantly sodium chloride precipitated, which was separated in the third separator (11) and sent to the sodium chloride receiver (12), the liquid phase in the form of a solution of potassium and magnesium chloride was sent to the second stage evaporator for obtaining carnallite (13), where the solution was evaporated until predominantly carnallite precipitated, which was separated from the steam in the fourth separator (14) and sent to the carnallite receiver (15), the separated steam was used for evaporation in the first stage evaporator (10) for obtaining carnallite, the obtained carnallite had a purity of 94.3%

[0060] Example 5.

[0061] The process of obtaining calcium chloride crystal hydrate was carried out similarly to Example No. 1, with the difference that additional separation of the solid phase from the liquid was carried out in a centrifuge after the second separator.

[0062] The calcium chloride concentrate contained impurities in the following quantities: Na - up to 1.1 g / l, Mg - up to 7.1 g / l, K - up to 3.2 g / l.

[0063] Example 6.

[0064] The process of obtaining calcium chloride crystal hydrate was carried out similarly to Example No. 1, with the difference that additional separation of the solid phase from the liquid was carried out on a belt filter after the second separator, which was made in the form of a settling tank.

[0065] The calcium chloride concentrate contained impurities in the following quantities: Na - up to 0.97 g / l, Mg - up to 6 g / l, K - up to 2.8 g / l.

[0066] Example 7.

[0067] The process of obtaining calcium chloride crystal hydrate was carried out similarly to Example No. 1, with the difference that the obtained crystal hydrate was dried in a drying cabinet until calcined calcium chloride was obtained.

[0068] Sources of information used:

[0069] 1. Patent RU2291109C2. C01F 11 / 24. Method for producing calcium chloride / Zagidullin R.N., Rasulev Z.G., Dmitriev Yu.K., Muratov M.M., Laponov A.S., Gumerova L.K., Anufrieva N.A. Application 12 / 21 / 2004, publ. 06 / 10 / 2006.

[0070] 2. Patent RU25502U1. C01F 11 / 24, C09K 3 / 18. Installation for producing calcium chloride / Rustambekov M.K., Taran A.L., Danilov V.P., Shchegolev A.I., Kuptsov L.A., Zudin A.B., Orlova V.T., Myasnikov S.K., Shchegolev I.A., Pirogov L.V. Applied 28.06.2002, published 10.10.2002.

[0071] 3. Patent US3536444A. C01F5 / 40. Method for separating brine components / Alfred F. Nylander. Applied 13.06.1969, published 27.10.1970. and 4. Patent US4224037A. B01D9 / 0031. Method for operating multiple-effect evaporators / Donald H. Giesen. Applied 03.04.1978, published 23.09.1980.

[0072] 5. Patent US4224035A. B01D9 / 0031. Method for separating salts from a solution / Donald H. Giesen. Claimed 03.04.1978, published 23.09.1980.

Claims

CLAUSE OF INVENTION 1. A method for producing calcium chloride from brine, comprising evaporating the initial brine in an evaporation unit comprising at least two evaporators, wherein the primary evaporation of the brine is carried out in the second evaporator using secondary steam obtained in the first evaporator, and the secondary evaporation is carried out using the initial steam in the first evaporator, resulting in the formation of secondary steam with a temperature lower than that of the initial steam, the initial brine being a calcium chloride type brine containing calcium chloride in an amount greater than 60% by weight, relative to impurities of other chlorides - sodium, potassium, magnesium, during evaporation of the initial brine in the second evaporator, with an increase in the concentration of salts in the brine, sodium, potassium and magnesium chlorides crystallize, which are separated in the second separator to obtain a solid phase and a calcium chloride concentrate,the calcium chloride concentrate is sent for evaporation in the first evaporator, where it is concentrated with precipitation of calcium chloride, the precipitate is separated from the steam in the first separator to obtain calcium chloride crystal hydrate.

2. The method according to claim 1, characterized in that the solid phase separated after the primary evaporation and containing sodium, potassium and magnesium chlorides is sent for stepwise washing with the dissolution of magnesium chloride first, then potassium chloride and subsequent separation of the crystalline material from the mother liquor, while hot water is used to dissolve the potassium chloride, and the potassium chloride is isolated from the solution by cooling.

3. The method according to paragraph 1, characterized in that at least one separator for separation into liquid and solid phases is made in the form of a settling tank, centrifuge or belt filter.

4. The method according to paragraph 1, characterized in that after separating the liquid and solid phases in at least one separator, the solid phase is additionally separated from the liquid phase in a centrifuge or belt filter.

5. The method according to item 1, characterized in that the obtained calcium chloride crystal hydrate is dried in a drying oven until calcined calcium chloride is obtained.

6. A method for producing calcium chloride from brine, comprising evaporating the initial brine in an evaporation unit comprising at least two evaporators, the primary evaporation of the brine is carried out in the second evaporator using secondary steam obtained in the first evaporator, and the secondary evaporation is carried out using the initial steam in the first evaporator, resulting in the formation of secondary steam with a temperature lower than that of the initial steam, the initial brine being a calcium chloride type brine containing calcium chloride in an amount of more than 60% by weight, relative to impurities of other chlorides - sodium, potassium, magnesium, during evaporation of the initial brine in the second evaporator, with an increase in the concentration of salts in the brine, sodium, potassium and magnesium chlorides crystallize, which are separated in the second separator to obtain a solid phase and a calcium chloride concentrate, the calcium chloride concentrate is sent for evaporation in the first evaporator, where it is concentrated with the precipitation of calcium chloride, the sediment is separated from the steam in the first separator to obtain calcium chloride crystal hydrate;the solid phase separated after the primary evaporation and containing sodium, potassium and magnesium is dissolved and used in the process of obtaining carnallite, the process of obtaining carnallite is carried out by evaporation in two stages, in the first stage steam with a lower temperature is used than for evaporation in the second stage, in the first stage of evaporation sodium chloride precipitates, the resulting mother liquor is sent to the second stage of evaporation, where during evaporation carnallite precipitates, which is separated.; 7. The method according to claim 6, characterized in that at the first stage of the process for obtaining carnallite, steam is used that was obtained by evaporating the mother liquor at the second stage of the process for obtaining carnallite.

8. The method according to item 6, characterized in that at the first stage of the process for obtaining carnallite, steam is used that was obtained in the first evaporator during the process of obtaining calcium chloride crystal hydrate.

9. The method according to claim 6, characterized in that the precipitate after the primary evaporation, containing sodium, potassium and magnesium, is dissolved in water to obtain a saturated solution.

10. The method according to item 6, characterized in that the separated carnallite is used to obtain magnesium or potassium chloride.

11. The method according to item 6, characterized in that at least one separator for separating into liquid and solid phases is made in the form of a settling tank, centrifuge or belt filter.

12. The method according to claim 6, characterized in that after separating the liquid and solid phases in at least one separator, the solid phase is additionally separated from the liquid phase in a centrifuge or belt filter.

13. The method according to claim 6, characterized in that the obtained calcium chloride crystal hydrate is dried in a drying oven until calcined calcium chloride is obtained.

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