A method and system for increasing the yield of ammonium carnallite produced by natural evaporation

Abstract

This invention provides a method and system for improving the yield of carnallite prepared by natural evaporation. The method involves natural evaporation of a first evaporation solution containing MgCl2 and NH4Cl to produce carnallite, and the NH4Cl in the solution... 十 When the concentration drops below the set concentration, the remaining solution is separated from the carnallite, and then NH4 is added to the separated remaining solution. + The process involves forming a second evaporation solution, which is then subjected to natural evaporation to continue producing anthracene. This invention improves the natural evaporation efficiency and anthracene yield by controlling the pyrogen ion content in the solution during natural evaporation and by performing multi-stage evaporation, thereby obtaining high-grade anthracene ore. This natural evaporation method not only has a high yield but also low energy consumption and cost, and can replace existing high-energy-consuming and high-cost anthracene preparation methods.

Description

Technical Field

[0001] This invention belongs to the field of ammonium carnallite preparation technology, specifically relating to a method and system for improving the yield of ammonium carnallite prepared by natural evaporation. Background Technology

[0002] Ammonium carnallite is an intermediate raw material for the preparation of anhydrous magnesium chloride, which in turn is used as a raw material for the electrolysis of metallic magnesium. The main process involves using magnesium chloride and ammonium chloride, byproducts of salt lakes, as raw materials to prepare ammonium carnallite. After dehydration, the ammonium carnallite yields anhydrous magnesium chloride, which is then used as a raw material for the electrolysis of metallic magnesium. Ammonium carnallite is chosen as the raw material for anhydrous magnesium chloride because it contains ammonium chloride, and the dehydration process using ammonium carnallite, regardless of the method employed, significantly inhibits the hydrolysis of magnesium chloride.

[0003] Common methods for preparing ammonium carnallite in existing technologies include forced heating evaporation crystallization, cooling crystallization, and vacuum distillation. These methods all require high energy consumption and sophisticated equipment, resulting in high costs. Natural evaporation crystallization can significantly save energy and reduce costs, but it suffers from low efficiency and low yield. Summary of the Invention

[0004] To solve all or part of the above-mentioned technical problems, the present invention provides the following technical solutions:

[0005] One objective of this invention is to provide a method for improving the yield of ammonium carnallite prepared by natural evaporation, the method comprising: naturally evaporating a first evaporation solution containing MgCl2 and NH4Cl to produce ammonium carnallite, and dissolving NH4Cl in the solution... + When the concentration drops below the set concentration, the remaining solution is separated from the ammonium carnallite, and then NH4 is added to the separated remaining solution. + To form a second evaporation solution, the second evaporation solution is then allowed to evaporate naturally to continue producing ammonium carnallite.

[0006] In some embodiments, the method specifically includes:

[0007] S1. The first evaporation solution is allowed to evaporate naturally, and the NH4+ in the solution... + When the concentration drops below the first set concentration, the precipitated ammonium carnallite is separated from the remaining solution, and then NH4 is added to the separated remaining solution. + To form a second evaporating solution;

[0008] S2. The second evaporation solution is allowed to evaporate naturally, and the NH4+ in the solution... +When the concentration drops below the second set concentration, the precipitated ammonium carnallite is separated from the remaining solution, and then the separated remaining solution is used to prepare the first evaporation solution.

[0009] In some embodiments, step S1 includes: replenishing NH4 at least by adding ammonium chloride solution to the separated residual solution. + .

[0010] Furthermore, the concentration of the ammonium chloride solution is 22.0–28.0 wt.%, and the mass ratio of the remaining solution to the ammonium chloride solution is 10:1–10:2.

[0011] In some embodiments, step S1 includes: adding NH4 to the separated residual solution. + To make NH4 + The second evaporation solution was obtained at a concentration of 2.50–4.0 wt.%, containing NH4. + The yield is higher when the concentration is within this range.

[0012] In some embodiments, step S1 includes: adding NH4 to the separated residual solution. + To make NH4 + The second evaporation solution was obtained with a concentration of 2.70–3.20 wt.%. If the evaporation solution contains NH4... + If the concentration is too high, ammonium chloride will be produced, affecting the purity of ammonium carnallite. If NH4+ is present... + If the concentration is too low, the yield will decrease.

[0013] In some embodiments, the first set concentration is 1.5 wt%. That is, when the NH4+ in the solution... + When the concentration drops below 1.5 wt%, the remaining solution is separated from ammonium carnallite, and then NH4 is added to the separated remaining solution. + .

[0014] In some embodiments, the second set concentration is 0.1 wt.%. That is, the NH4+ concentration in the solution is... + When the concentration is reduced to below 0.1 wt.%, the precipitated ammonium carnallite is separated from the remaining solution.

[0015] In some embodiments, the concentration of MgCl2 in the first evaporation solution is 16.0–21.0 wt.%, and the concentration of NH4Cl is 10.0–11.0 wt.%.

[0016] like Figure 2 As shown, the method provided by this invention controls the system point of the evaporation system between L1 and L2. The first natural evaporation occurs when the system point is near L1 (NH4Cl concentration is around 10 wt%), and when the system point is close to L2 (NH4Cl concentration is around 10 wt%), the evaporation proceeds naturally.+ When the concentration is around 1.5 wt%, adjust the NH4 in the evaporating solution. + The concentration is adjusted so that the system point is between L1 and L2, and then a second evaporation is performed, at which point a higher yield is obtained. Therefore, in the above technical solution, the concentration of NH4Cl in the first evaporation solution is controlled to be 10.0–11.0 wt.%, and the concentration of NH4Cl is... + The concentration was adjusted by reducing it to 1.5 wt%, and NH4 was made... + A concentration of 2.70–3.20 wt.% is beneficial for increasing the yield, and the resulting ammonium carnallite has a high purity.

[0017] In some embodiments, the yield of ammonium carnallite produced by the method is above 64.0%.

[0018] In some embodiments, the ammonium carnallite obtained by the method has a purity of 93.0% or higher.

[0019] In some embodiments, the ammonium carnallite obtained by the method has a particle size of 312.4–364.3 μm.

[0020] In existing technologies, the average particle size of ammonium carnallite obtained by cooling crystallization is 250.5–215.4 μm, and the yield of this process is only 57.4%, which is low. The average particle size of ammonium carnallite obtained by spray drying is 3.17–15.74 μm, and the product particle size is small, which does not meet the requirements of subsequent processes. However, the method provided by this invention has a higher yield and produces ammonium carnallite with better morphology and higher purity.

[0021] The MgCl2 can be obtained by using Epsom salt hexahydrate, a waste product from salt lakes, to achieve resource recycling.

[0022] The second objective of this invention is to provide a system for improving the yield of ammonium carnallite prepared by natural evaporation, the system comprising a first evaporation unit and NH4 + The unit includes a supplementary unit, a second evaporation unit, and an ammonium carnallite storage unit.

[0023] The first evaporation unit is used to allow a first evaporation solution containing MgCl2 and NH4Cl to evaporate naturally, producing ammonium carnallite, and the NH4Cl in the solution... + When the concentration drops below the first set concentration, the remaining solution is separated from the ammonium carnallite;

[0024] The NH4 + The replenishment unit is used to replenish NH4 to the separated residual solution. + To form a second evaporating solution;

[0025] The second evaporation unit is used to allow the second evaporation solution to evaporate naturally in order to continue producing ammonium carnallite, and to release NH4 in the solution. + When the concentration drops below the second set concentration, the remaining solution is separated from the ammonium carnallite;

[0026] The ammonium carnallite storage unit is used to store the ammonium carnallite separated from the first evaporation unit and the second evaporation unit.

[0027] The third objective of this invention is to provide a method for improving the yield of ammonium carnallite prepared by natural evaporation, comprising:

[0028] The first evaporation unit is used to naturally evaporate the first evaporation solution containing MgCl2 and NH4Cl to produce ammonium carnallite, and the NH4 in the solution... + When the concentration drops below the first set concentration, the precipitated ammonium carnallite is separated from the remaining solution by the first solid-liquid separation mechanism, and then NH4 is used. + The replenishment unit adds NH4 to the separated residual solution. + To form a second evaporating solution;

[0029] The second evaporation device is used to naturally evaporate the second evaporation solution, and the NH4 in the solution... + When the concentration drops below the second set concentration, the precipitated ammonium carnallite is separated from the remaining solution by the second solid-liquid separation mechanism, and then the separated remaining solution is input into the first evaporation mechanism.

[0030] Compared with the prior art, the present invention has at least the following beneficial effects:

[0031] This invention improves the efficiency of natural evaporation and the yield of ammonium carnallite by controlling the ammonium ion content in the solution during natural evaporation and performing multi-stage evaporation, thereby obtaining high-grade ammonium carnallite ore. This natural evaporation method has high yield, low energy consumption, and low cost, and can replace existing high-energy-consuming and high-cost ammonium carnallite preparation methods such as forced heating evaporation crystallization, cooling crystallization, and vacuum distillation. It can also use Epsom hexahydrate waste from salt lakes as raw material, which meets the needs of sustainable development.

[0032] This invention improves the yield and increases the average particle size of ammonium carnallite by controlling the natural evaporation process and adjusting the ammonium ion content in the solution during the later stage of evaporation. This provides a good raw material for the subsequent dehydration and magnesium metal preparation processes. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a process flow diagram of a natural evaporation method for improving the yield of ammonium carnallite in one embodiment of the present invention;

[0035] Figure 2 The Mg in the evaporation system of this invention 2+ NH4 + / / Cl - -H2O phase diagram;

[0036] Figure 3 , Figure 4 , Figure 5 , Figure 6 This is a scanning electron microscope image of ammonium carnallite obtained by the method described in this invention. Detailed Implementation

[0037] The technical solutions of the present invention will be described in detail below with reference to specific embodiments, so that those skilled in the art can better understand and implement the technical solutions of the present invention. The specific functional details disclosed herein should not be construed as limiting, but are merely intended to form the basis of the claims and to teach those skilled in the art to employ the representative basis of the invention in different ways in any suitable detailed embodiment.

[0038] Example 1

[0039] This embodiment provides a system for improving the yield of ammonium carnallite preparation by natural evaporation. The system includes a first evaporation unit and NH4... + The unit comprises a replenishment unit, a second evaporation unit, and an ammonium carnallite storage unit. The first evaporation unit includes a first evaporation mechanism (e.g., an evaporation stock solution storage tank) for storing the first evaporation solution L1 and performing primary natural evaporation. This first evaporation unit also includes a first solid-liquid separation mechanism for separating the solid-liquid mixture obtained after primary natural evaporation. The separated solid is ammonium carnallite, which is transferred to the ammonium carnallite storage unit for storage. The remaining solution L3 obtained after separation is introduced into the second evaporation mechanism of the second evaporation unit. + The replenishment unit injects a certain concentration of ammonium chloride solution L2 into it, so that the NH4+ in the solution of the second evaporation unit increases. +Once the concentration reaches a certain value, a second evaporation solution L4 is obtained, which is then subjected to secondary evaporation. This second evaporation unit also includes a second solid-liquid separation mechanism, which separates the solid-liquid mixture obtained from the secondary natural evaporation. The separated solid ammonium carnallite is transferred to an ammonium carnallite storage unit for storage, while the remaining solution L5 is fed into the evaporation stock solution storage tank of the first evaporation unit, achieving solution recycling. NH4 is provided in both the first and second evaporation units. + Concentration testing facility, used to detect NH4 + concentration.

[0040] This embodiment also provides a method for improving the yield of ammonium carnallite prepared by natural evaporation, using the system described above. Figure 1 The process flow diagram of the method for improving the yield of ammonium carnallite by natural evaporation provided in this embodiment is as follows:

[0041] (1) Prepare the solution

[0042] The first evaporation solution L1 was prepared using Epsom salt hexahydrate (MgCl2·6H2O), industrial ammonium chloride (NH4Cl), and water. Its concentration composition was as follows: MgCl2 content 16.0 wt.%, NH4Cl content 10.0 wt.%, and H2O content 74.0 wt.%.

[0043] An ammonium chloride solution L2 was prepared using industrial ammonium chloride (NH4Cl) and water, with the following concentration composition: NH4Cl content 22.0 wt.%, H2O content 78.0 wt.%.

[0044] (2) 30.0 kg of the first evaporation solution L1 was injected into the evaporation stock solution storage tank, and it was subjected to first-stage natural evaporation. The NH4+ produced during the first-stage natural evaporation process was also controlled. + The content was detected when NH4 was present in the solution. + When the content is 1.5 wt.%, the solid-liquid mixture in the evaporation stock tank is separated to obtain 15.5 kg of solid phase, which is ammonium carnallite (S1). The ammonium carnallite is transferred to the ammonium carnallite collection unit for storage. The remaining solution (L3) of 8.1 kg is separated and introduced into the second evaporation mechanism of the second evaporation unit.

[0045] (3) Add 810g of ammonium chloride solution L2 to the second evaporation unit and adjust the NH4+. + The concentration was increased to 2.70 wt.%, yielding a second evaporation solution L4. This second evaporation solution L4 was then subjected to a second stage of natural evaporation, and the NH4+ ions in the solution were analyzed during the second stage of natural evaporation. + The content was detected when the NH4 in the solution was... +When the content is reduced to 0.1 wt.%, the resulting solid-liquid mixture is separated, and 3.8 kg of solid phase is obtained, which is ammonium carnallite (S2). It is placed in the ammonium carnallite storage unit for storage, and 1.5 kg of the remaining solution (L5) obtained from the separation is introduced into the evaporation stock solution storage tank.

[0046] Figure 2 Mg in the evaporation system 2+ NH4 + / / Cl - -H2O phase diagram; Figure 3 , Figure 4 , Figure 5 , Figure 6 These are scanning electron microscope (SEM) images of ammonium carnallite obtained in this embodiment at different magnifications.

[0047] Ammonium carnallite yield in this embodiment: The produced solid S2 has a purity of 95.4% and an average particle size of 312.4 μm.

[0048] Example 2

[0049] (1) Prepare the solution

[0050] The first evaporation solution L1 was prepared using Epsom salt hexahydrate (MgCl2·6H2O), industrial ammonium chloride (NH4Cl), and water. The concentration composition of L1 was as follows: MgCl2 content 21.0 wt.%, NH4Cl content 11.0 wt.%, and H2O content 68.0 wt.%.

[0051] An ammonium chloride solution L2 was prepared using industrial ammonium chloride (NH4Cl) and water, with the following concentration composition: NH4Cl content 28.0 wt.%, H2O content 72.0 wt.%.

[0052] (2) 30.0 kg of the first evaporation solution L1 was injected into the evaporation stock solution storage tank for primary natural evaporation, and the NH4+ produced during the primary natural evaporation process was controlled. + The content was detected when the NH4 in the solution was... + When the content is 1.4 wt.%, the solid-liquid mixture in the evaporation stock tank is separated to obtain 16.1 kg of solid phase, which is ammonium carnallite (S1). The ammonium carnallite is transferred to the ammonium carnallite collection unit for storage. The remaining solution (L3) of 8.2 kg is separated and introduced into the second evaporation mechanism of the second evaporation unit.

[0053] (3) Add 1640g of ammonium chloride solution L2 to the second evaporation unit and adjust the NH4+. + The concentration was increased to 3.00 wt.%, resulting in a second evaporation solution L4. This second evaporation solution L4 was then subjected to a second stage of natural evaporation, and the NH4+ content in the solution during this second stage of natural evaporation was analyzed.+ The content was detected when the NH4 in the solution was... + When the content is reduced to 0.08 wt.%, the resulting solid-liquid mixture is separated, and 3.3 kg of solid phase is obtained, which is ammonium carnallite (S2), which is stored in the ammonium carnallite storage unit. 1.6 kg of the separated solution (L5) is introduced into the evaporation stock solution storage tank.

[0054] Ammonium carnallite yield in this embodiment: The produced solid S2 has a purity of 93.5% and an average particle size of 355.5 μm.

[0055] Example 3

[0056] (1) Prepare the solution

[0057] The first evaporation solution L1 was prepared using Epsom salt hexahydrate (MgCl2·6H2O), industrial ammonium chloride (NH4Cl), and water, with the following concentration composition: MgCl2 content 20.0 wt.%, NH4Cl content 10.5 wt.%, and H2O content 69.5 wt.%.

[0058] An industrial ammonium chloride (NH4Cl) and water were used to prepare an ammonium chloride solution L2 with the following concentration composition: NH4Cl content 26.0 wt.%, H2O content 74.0 wt.%.

[0059] (2) 30.0 kg of the first evaporation solution L1 was injected into the evaporation stock tank and subjected to first-stage natural evaporation. The NH4+ produced during the first-stage natural evaporation process was then controlled. + The content was detected when the NH4 in the solution was... + With a content of 1.5 wt.%, the solid-liquid mixture in the evaporation stock tank was separated to obtain 17.4 kg of solid phase, which is ammonium carnallite (S1). The ammonium carnallite was transferred to the ammonium carnallite collection unit for storage, and 7.9 kg of mixed solution (L3) was separated and introduced into the second evaporation mechanism of the second evaporation unit.

[0060] (3) Add 830g of ammonium chloride solution L2 to the second evaporation unit and adjust the NH4+. + The concentration was increased to 3.20 wt.%, yielding the second evaporation solution L4. This second evaporation solution L4 was then subjected to a second stage of natural evaporation, and the NH4+ ions in the solution were analyzed during the second stage of natural evaporation. + The content was detected when NH4 was present in the solution. + When the content is reduced to 0.1 wt.%, the resulting solid-liquid mixture is separated, and 2.5 kg of solid phase is obtained, which is ammonium carnallite (S2), which is stored in the ammonium carnallite storage unit. 1.3 kg of the separated solution (L5) is introduced into the evaporation stock solution storage tank.

[0061] Ammonium carnallite yield in this embodiment: The produced solid S2 has a purity of 97.0% and an average particle size of 364.3 μm.

[0062] Example 4

[0063] (1) Prepare the solution

[0064] The first evaporation solution L1 was prepared using Epsom salt hexahydrate (MgCl2·6H2O), industrial ammonium chloride (NH4Cl), and water, with the following concentration composition: MgCl2 content 20.0 wt.%, NH4Cl content 10.5 wt.%, and H2O content 69.5 wt.%.

[0065] An industrial ammonium chloride (NH4Cl) and water were used to prepare an ammonium chloride solution L2 with the following concentration composition: NH4Cl content 19.0 wt.%, H2O content 81.0 wt.%.

[0066] (2) 30.0 kg of the first evaporation solution L1 was injected into the evaporation stock tank and subjected to first-stage natural evaporation. The NH4+ produced during the first-stage natural evaporation process was then controlled. + The content was detected when the NH4 in the solution was... + With a content of 1.5 wt.%, the solid-liquid mixture in the evaporation stock tank was separated to obtain 17.4 kg of solid phase, which is ammonium carnallite (S1). The ammonium carnallite was transferred to the ammonium carnallite collection unit for storage, and 7.9 kg of mixed solution (L3) was separated and introduced into the second evaporation mechanism of the second evaporation unit.

[0067] (3) Add 830g of ammonium chloride solution L2 to the second evaporation unit and adjust the NH4+. + The concentration was adjusted to 2.50 wt.%, yielding the second evaporation solution L4. This second evaporation solution L4 was then subjected to a second stage of natural evaporation, and the NH4+ ions in the solution were analyzed during this process. + The content was tested, and when the NH4+ content in the solution decreased to 0.1 wt.%, the resulting solid-liquid mixture was separated. 1.3 kg of solid phase was obtained, which is ammonium carnallite (S2), and it was placed in the ammonium carnallite storage unit for storage. 1.9 kg of the separated solution (L5) was introduced into the evaporation stock solution storage tank.

[0068] Ammonium carnallite yield in this embodiment:

[0069] Example 5

[0070] (1) Prepare the solution

[0071] The first evaporation solution L1 was prepared using Epsom salt hexahydrate (MgCl2·6H2O), industrial ammonium chloride (NH4Cl), and water, with the following concentration composition: MgCl2 content 20.0 wt.%, NH4Cl content 10.5 wt.%, and H2O content 69.5 wt.%.

[0072] An industrial ammonium chloride (NH4Cl) and water were used to prepare an ammonium chloride solution L2 with the following concentration composition: NH4Cl content 32.5 wt.%, H2O content 67.5 wt.%.

[0073] (2) 30.0 kg of the first evaporation solution L1 was injected into the evaporation stock tank and subjected to first-stage natural evaporation. The NH4+ produced during the first-stage natural evaporation process was then controlled. + The content was detected when the NH4 in the solution was... + With a content of 1.5 wt.%, the solid-liquid mixture in the evaporation stock tank was separated to obtain 17.4 kg of solid phase, which is ammonium carnallite (S1). The ammonium carnallite was transferred to the ammonium carnallite collection unit for storage, and 7.9 kg of mixed solution (L3) was separated and introduced into the second evaporation mechanism of the second evaporation unit.

[0074] (3) Add 830g of ammonium chloride solution L2 to the second evaporation unit and adjust the NH4+. + The concentration was adjusted to 3.80 wt.%, yielding the second evaporation solution L4. This second evaporation solution L4 was then subjected to a second stage of natural evaporation, and the NH4+ ions in the solution were analyzed during this process. + The content was detected when NH4 was present in the solution. + When the content is reduced to 0.1 wt.%, the resulting solid-liquid mixture is separated, and 2.9 kg of solid phase is obtained, which is ammonium carnallite (S2), which is placed in the ammonium carnallite storage unit for storage. 1.4 kg of the separated solution (L5) is introduced into the evaporation stock solution storage tank.

[0075] Ammonium carnallite yield in this embodiment: The purity of the produced solid S2 was 75.7% (Mg). 2+ The content is 7.04%.

[0076] Example 6

[0077] (1) Prepare the solution

[0078] The first evaporation solution L1 was prepared using Epsom salt hexahydrate (MgCl2·6H2O), industrial ammonium chloride (NH4Cl), and water, with the following concentration composition: MgCl2 content 20.0 wt.%, NH4Cl content 10.5 wt.%, and H2O content 69.5 wt.%.

[0079] An industrial ammonium chloride (NH4Cl) and water were used to prepare an ammonium chloride solution L2 with the following concentration composition: NH4Cl content 26.0 wt.%, H2O content 74.0 wt.%.

[0080] (2) 30.0 kg of the first evaporation solution L1 was injected into the evaporation stock tank and subjected to first-stage natural evaporation. The NH4+ produced during the first-stage natural evaporation process was then controlled. + The content was detected when the NH4 in the solution was... + The content is 1.9 wt.%. The solid-liquid mixture in the evaporation stock tank is separated to obtain 17.4 kg of solid phase, which is ammonium carnallite (S1). The ammonium carnallite is transferred to the ammonium carnallite collection unit for storage. The mixed solution (L3) 7.9 kg is separated and introduced into the second evaporation mechanism of the second evaporation unit.

[0081] (3) Add 830g of ammonium chloride solution L2 to the second evaporation unit and adjust the NH4+. + The concentration was reduced to 3.65 wt.%, yielding the second evaporation solution L4. This second evaporation solution L4 was then subjected to a second stage of natural evaporation, and the NH4+ ions in the solution were analyzed during this process. + The content was detected when NH4 was present in the solution. + When the content is reduced to 0.1 wt.%, the resulting solid-liquid mixture is separated, and 2.5 kg of solid phase is obtained, which is ammonium carnallite (S2), which is stored in the ammonium carnallite storage unit. 1.3 kg of the separated solution (L5) is introduced into the evaporation stock solution storage tank.

[0082] Ammonium carnallite yield in this embodiment: Ammonium chloride is generated in the S2 solid ore, which slightly reduces the purity of ammonium carnallite.

[0083] Example 7

[0084] (1) Prepare the solution

[0085] The first evaporation solution L1 was prepared using Epsom salt hexahydrate (MgCl2·6H2O), industrial ammonium chloride (NH4Cl), and water. Its concentration composition was as follows: MgCl2 content 25.0 wt.%, NH4Cl content 9.0 wt.%, and H2O content 66.0 wt.%.

[0086] An industrial ammonium chloride (NH4Cl) and water were used to prepare an ammonium chloride solution L2 with the following concentration composition: NH4Cl content 26.0 wt.%, H2O content 74.0 wt.%.

[0087] (2) 30.0 kg of the first evaporation solution L1 was injected into the evaporation stock tank and subjected to first-stage natural evaporation. The NH4+ produced during the first-stage natural evaporation process was then controlled. +The content was detected when the NH4 in the solution was... + The content is 1.9 wt.%. The solid-liquid mixture in the evaporation stock tank is separated to obtain 17.4 kg of solid phase, which is ammonium carnallite (S1). The ammonium carnallite is transferred to the ammonium carnallite collection unit for storage. The mixed solution (L3) 7.9 kg is separated and introduced into the second evaporation mechanism of the second evaporation unit.

[0088] (3) Add 830g of ammonium chloride solution L2 to the second evaporation unit and adjust the NH4+. + The concentration was increased to 4.00 wt.%, yielding the second evaporation solution L4. This second evaporation solution L4 was then subjected to a second stage of natural evaporation, and the NH4+ in the solution was analyzed during the second stage of natural evaporation. + The content was detected when NH4 was present in the solution. + When the content is reduced to 0.1 wt.%, the resulting solid-liquid mixture is separated, and 2.5 kg of solid phase is obtained, which is ammonium carnallite (S2), which is stored in the ammonium carnallite storage unit. 1.3 kg of the separated solution (L5) is introduced into the evaporation stock solution storage tank.

[0089] The composition of S1 is: Mg 2+ 11.25 wt.%, NH4 + 0.85 wt.%, Cl - The purity of the product decreased by 34.50 wt.%, and ammonium chloride was generated in the S2 solid ore, which slightly reduced the purity of ammonium carnallite.

[0090] Ammonium carnallite yield in this embodiment:

[0091] Comparative Example 1

[0092] (1) Prepare the solution

[0093] The first evaporation solution L1 was prepared using Epsom salt hexahydrate (MgCl2·6H2O), industrial ammonium chloride (NH4Cl), and water, with the following concentration composition: MgCl2 content 20.0 wt.%, NH4Cl content 10.5 wt.%, and H2O content 69.5 wt.%.

[0094] (2) 30.0 kg of the first evaporation solution L1 was injected into the evaporation stock solution storage tank and allowed to evaporate naturally. During the natural evaporation process, NH4+... + The content was detected when the NH4 in the solution was... + With a content of 0.15 wt.%, the solid-liquid mixture in the evaporation stock tank was separated to obtain 17.4 kg of solid phase, which is ammonium carnallite.

[0095] Ammonium carnallite yield in this embodiment: The average particle size is 315.4 μm.

[0096] Table 1. Relevant properties of ammonium carnallite prepared in the above examples and comparative examples.

[0097] Example 1 64.2％ 93.2％ Example 2 64.7％ 95.7％ Example 3 66.3％ 98.1％ Example 4 62.3％ 93.1％ Example 5 67.7％ 75.7％ Example 6 66.3％ 88.5％ Example 7 66.3％ 12.1％ Comparative Example 1 58.0％ 92.1％

[0098] All aspects, embodiments, features, and examples of this invention are to be regarded as illustrative in all respects and are not intended to limit the invention, the scope of which is defined only by the claims. Other embodiments, modifications, and uses will become apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0099] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0100] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated otherwise, any use of the terms first, second, etc., does not indicate any order or importance, but is used to distinguish one element from another.

Claims

1. A method for improving the yield of ammonium carnallite prepared by natural evaporation, characterized in that, Specifically, it includes: S1. The first evaporation solution containing MgCl2 and NH4Cl at a concentration of 10.0~11.0 wt.% is subjected to natural evaporation, and the NH4Cl in the solution is... + When the concentration drops below 1.5 wt%, the precipitated ammonium carnallite is separated from the remaining solution, and then NH4 is added to the separated remaining solution. + To form NH4 + A second evaporation solution with a concentration of 2.70~3.20 wt.%; S2. The second evaporation solution is allowed to evaporate naturally, and the NH4+ in the solution... + When the concentration drops below 0.1 wt.%, the precipitated ammonium carnallite is separated from the remaining solution. The separated remaining solution is then used to prepare the first evaporation solution to continue producing ammonium carnallite.

2. The method according to claim 1, characterized in that, Step S1 includes: replenishing NH4 at least by adding ammonium chloride solution to the separated residual solution. + .

3. The method according to claim 1, characterized in that: The concentration of MgCl2 in the first evaporation solution is 16.0~21.0 wt.%.

4. The method according to claim 2, characterized in that: The concentration of the ammonium chloride solution is 22.0~28.0 wt.%, and the mass ratio of the remaining solution to the ammonium chloride solution is 10:1~10:

2.

5. The method according to any one of claims 1-4, characterized in that: The yield of ammonium carnallite produced by the method is over 64.0%.

6. The method according to any one of claims 1-4, characterized in that: The ammonium carnallite obtained by the method has a purity of over 93.0%.

7. The method according to any one of claims 1-4, characterized in that: The average particle size of the ammonium carnallite obtained by the method is 312.4~364.3 μm.

8. A method for improving the yield of ammonium carnallite prepared by natural evaporation, characterized in that, include: The first evaporation unit is used to naturally evaporate a first evaporation solution containing MgCl2 and NH4Cl at a concentration of 10.0~11.0 wt.% to produce ammonium carnallite, and the NH4Cl in the solution is then evaporated. + When the concentration drops below 1.5 wt%, the precipitated ammonium carnallite is separated from the remaining solution using the first solid-liquid separation mechanism, and then treated with NH4. + The replenishment unit adds NH4 to the separated residual solution. + To form NH4 + A second evaporation solution with a concentration of 2.70~3.20 wt.%; The second evaporation device is used to naturally evaporate the second evaporation solution, and the NH4 in the solution... + When the concentration drops below 0.1 wt.%, the precipitated ammonium carnallite is separated from the remaining solution by the second solid-liquid separation mechanism, and then the separated remaining solution is fed into the first evaporation mechanism.

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