Method for preparing anhydrous chlorinated metal salt based on molten salt medium and double decomposition reaction

Abstract

The invention relates to the technical field of chlorinated metal salt preparation, in particular to a method for preparing anhydrous chlorinated metal salt based on a molten salt medium and double decomposition reaction. The metal chloride salt comprises aluminum chloride or gallium chloride, and the method comprises the following steps: melting chloride salt containing calcium chloride to obtain molten salt; mixing anhydrous calcium chloride and anhydrous sulfuric acid metal salt to obtain a mixed raw material; performing double decomposition reaction on the mixed raw material and the molten salt to obtain gaseous anhydrous chlorinated metal salt; the feeding speed v1 of the mixed raw materials and the mass m1 of the molten salt meet the condition that v1: m1 is larger than or equal to 6: 100, and if the unit of v1 is kg / h, the unit of m1 is kg; the temperature of double decomposition reaction is not less than 530 DEG C; and condensing the gaseous anhydrous chlorinated metal salt to obtain an anhydrous chlorinated metal salt solid product. According to the method, the purity of the anhydrous chlorinated metal salt solid product and the utilization rate of the raw material sulfuric acid metal salt can be improved through a series of means of controlling the reaction medium, the feeding speed, the reaction temperature and the like.

Description

Technical Field

[0001] The present application relates to the technical field of preparation of metal chloride salts, and in particular to a method for preparing anhydrous metal chloride salts based on a double decomposition reaction in a molten salt medium. Background Art

[0002] Anhydrous aluminum chloride and anhydrous gallium chloride are both important chemical raw materials with a wide range of uses. However, both compounds easily react chemically with water or water vapor to form hydrates, making it impossible to prepare high-purity products by roasting the crystalline hydrates of their inorganic salts.

[0003] Currently, anhydrous metal chlorides are mainly prepared at high temperatures using hazardous chlorinating agents such as chlorine, hydrogen chloride, and thionyl chloride with aluminum- or gallium-containing raw materials. However, since these chlorinating agents mostly react on the surface of the aluminum- or gallium-containing raw materials, the overall chlorinating agent utilization rate is low. In addition, these chlorinating agents are expensive, and the reaction also carries the risk of hazardous gas leakage. Summary of the Invention

[0004] The present application provides a method for preparing anhydrous chlorinated metal salts based on a molten salt medium and a double decomposition reaction, in order to solve the following technical problem: how to balance the utilization rate of the chlorinating agent and the purity of the product.

[0005] In a first aspect, the present application provides a method for preparing anhydrous metal chloride salt based on a molten salt medium and a double decomposition reaction, wherein the metal chloride salt includes aluminum chloride or gallium chloride, and the method comprises:

[0006] melting a chloride salt containing calcium chloride to obtain a molten salt;

[0007] Mixing anhydrous calcium chloride and anhydrous metal sulfate to obtain a mixed raw material; wherein the anhydrous metal sulfate includes anhydrous aluminum sulfate or anhydrous gallium sulfate;

[0008] The mixed raw material and the molten salt are subjected to a double decomposition reaction to obtain a gaseous anhydrous chloride metal salt; wherein the feeding rate v1 of the mixed raw material and the mass m1 of the molten salt satisfy the relationship: v1:m1≥6:100, if the unit of v1 is g / h, the unit of m1 is g; the temperature of the double decomposition reaction is ≥530°C;

[0009] The gaseous anhydrous metal chloride salt is condensed to obtain an anhydrous metal chloride salt solid product.

[0010] Optionally, the feeding rate v1 of the mixed raw material and the mass m1 of the molten salt satisfy the relationship: v1:m1=(6-65):100, and if the unit of v1 is kg / h, the unit of m1 is kg.

[0011] Optionally, the temperature of the metathesis reaction is 530° C. to 700° C., and the time of the metathesis reaction is 0.5 min to 120 min.

[0012] Optionally, the amount n1 of the anhydrous calcium chloride and the amount n2 of the anhydrous metal sulfate satisfy the relationship: n1:n2=(1.45-1.55):1.

[0013] Optionally, the chloride salt further includes sodium chloride and / or potassium chloride.

[0014] Optionally, when the chloride salt includes sodium chloride and calcium chloride, the mass m2 of the sodium chloride and the mass m3 of the calcium chloride satisfy the relationship: m2:m3=1:(1-2); and / or

[0015] When the chloride salt includes sodium chloride, potassium chloride and calcium chloride, the mass of the potassium chloride is 5% to 20% of the total mass of the chloride salt, and the mass m2 of the sodium chloride and the mass m3 of the calcium chloride satisfy the relationship: m2:m3=(2:7) to (1:2).

[0016] Optionally, the melting temperature is 530°C to 700°C.

[0017] Optionally, the step of subjecting the mixed raw material and the molten salt to a double decomposition reaction to obtain a gaseous anhydrous chloride metal salt comprises the following steps:

[0018] The mixed raw material and the molten salt are subjected to a double decomposition reaction to obtain gaseous anhydrous aluminum chloride or gallium chloride and a waste residue containing calcium sulfate, respectively;

[0019] crystallizing the calcium sulfate-containing waste residue to obtain a waste molten salt containing crystallized calcium sulfate waste residue;

[0020] Separating the waste molten salt containing crystallized calcium sulfate waste residue to obtain crystallized calcium sulfate waste residue and molten salt;

[0021] washing and filtering the crystallized calcium sulfate waste residue in sequence to obtain a salt-containing filtrate and calcium sulfate waste residue, respectively;

[0022] Concentrating and crystallizing the salt-containing filtrate to obtain a crystal mixture;

[0023] The crystal mixture is dried to obtain anhydrous chloride salt containing calcium chloride.

[0024] Optionally, the temperature of the crystallization treatment is 520° C. to 680° C., and the time of the crystallization treatment is 30 min to 720 min.

[0025] Optionally, the separation temperature is 500°C to 650°C.

[0026] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0027] The present invention provides a method for preparing anhydrous metal chloride salts based on double decomposition reaction. The core of the method is to use molten calcium chloride-containing chloride salts as the reaction medium. The specific steps are as follows:

[0028] First, a molten chloride salt containing calcium chloride is selected as the molten medium for the entire reaction. Subsequently, anhydrous calcium chloride and anhydrous aluminum sulfate or gallium sulfate are introduced into the reaction system as a mixed raw material. These two raw materials are selected to achieve the exchange of specific elements through a metathesis reaction.

[0029] During the reaction, a double decomposition reaction occurs between the chloride salt in the molten medium, the introduced anhydrous calcium chloride, and anhydrous aluminum sulfate or gallium sulfate. This reaction causes the chlorine element in the calcium chloride to combine with the target metal element to form the target chloride metal salt. Simultaneously, the sulfate ion combines with the calcium element to produce a waste residue containing calcium sulfate.

[0030] To ensure efficient reaction performance, this method specifically prioritizes the ratio between the feed rate v1 of the mixed raw materials and the mass m1 of the molten salt. Specifically, the ratio should satisfy the equation v1:m2 ≥ 6:100. This design allows the feed rate to be dynamically adjusted as the mass of the molten salt changes, thereby optimizing reaction conditions and promoting the full potential of the double decomposition reaction, ensuring sufficient production of the target metal chloride salt and calcium sulfate-containing waste residue.

[0031] In addition, the reaction temperature is set to ≥530 ℃, and this high temperature condition is conducive to the rapid progress of the reaction. More importantly, based on the significant gasification temperature difference between the target metal chloride salt and the calcium sulfate-containing waste residue, the reaction product can be effectively separated between the gaseous state (aluminum chloride or gallium chloride) and the solid state (calcium sulfate-containing waste residue) and the molten chloride salt. This separation process provides convenience for the subsequent acquisition of high-purity anhydrous metal chloride solid products by condensation means, thereby significantly improving the purity of the final product. In summary, the embodiment of the present application is regulated by carefully designed reaction medium, raw material ratio, feeding rate control and reaction temperature, to achieve efficient and high-purity preparation of anhydrous metal chloride salt. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0034] Figure 1 A schematic flow chart of a method for preparing anhydrous metal chloride salts based on a molten salt medium and a double decomposition reaction provided in an embodiment of the present application;

[0035] Figure 2 A detailed flow chart of a method for preparing anhydrous metal chloride salts based on a molten salt medium and a double decomposition reaction is provided in an embodiment of the present application. DETAILED DESCRIPTION

[0036] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0037] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values within the range; for example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range; in addition, whenever a numerical range is indicated in this document, it is meant to include any cited number (fractional or integer) within the indicated range.

[0038] As used herein, the terms "including," "comprising," and the like mean "including but not limited to." Relational terms such as "first" and "second" are used solely to distinguish one entity or operation from another, and do not necessarily require or imply any actual relationship or order between these entities or operations. "And / or" describes the association relationship between associated objects, indicating that three relationships can exist. For example, "A and / or B" can mean: A exists alone, A and B exist at the same time, and B exists alone; where A and B can be singular or plural. "At least one" means one or more, "plurality" means two or more; "at least one," "at least one of the following," or similar expressions, refers to any combination of these items, including any combination of single or plural items; for example, "at least one of a, b, or c," or "at least one of a, b, and c," can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can each be single or plural. "Parts" notation, such as parts by weight or parts by mass, indicates the proportional relationship between components. In this article, the parameters described by ratio should be understood as the first term of the proportional formula, in the order in which they are described, and the proportional figures should be understood as the second term. For example, if the mass ratio of substances A, B, and C is 1:2:3, then substances A, B, and C should correspond to the proportional figures in the proportional formula, in the order in which they are described: that is, the mass of substance A:the mass of substance B:the mass of substance C = 1:2:3.

[0039] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this article can be purchased from the market or prepared by existing methods.

[0040] Figure 1 A schematic flow chart of a method for preparing anhydrous metal chloride salts based on a molten salt medium and a double decomposition reaction provided in an embodiment of the present application;

[0041] like Figure 1 As shown, an embodiment of the present application provides a method for preparing anhydrous metal chloride salt based on a molten salt medium and a double decomposition reaction, wherein the metal chloride salt includes aluminum chloride or gallium chloride, and the method includes:

[0042] S1. The chloride salt containing calcium chloride is melted to obtain a molten salt;

[0043] S2. Mixing anhydrous calcium chloride and anhydrous metal sulfate to obtain a mixed raw material; wherein the anhydrous metal sulfate comprises anhydrous aluminum sulfate or anhydrous gallium sulfate;

[0044] S3. Performing a double decomposition reaction on the mixed raw material and the molten salt to obtain a gaseous anhydrous chloride metal salt; wherein the feed rate v1 of the mixed raw material and the mass m1 of the molten salt satisfy the relationship: v1:m1 ≥ 6:100, where if v1 is expressed in g / h, m1 is expressed in g; and the temperature of the double decomposition reaction is ≥ 530°C;

[0045] S4. Condensing the gaseous anhydrous metal chloride salt to obtain an anhydrous metal chloride salt solid product.

[0046] It should be noted that the melting can be carried out using a molten salt tank, and the working time of the molten salt tank is determined comprehensively according to the quality of the molten material and the melting rate.

[0047] It should be noted that the embodiment of the present application provides a method for preparing anhydrous chloride metal salts based on a molten salt medium and a double decomposition reaction. The method has unique innovations and significant advantages. The specific process includes:

[0048] The method first carefully selects a molten chloride salt containing calcium chloride as the reaction medium. This molten salt plays a crucial role in the reaction system, providing a stable and suitable environment for subsequent chemical reactions. Subsequently, anhydrous calcium chloride and anhydrous aluminum sulfate or gallium sulfate are added to the reaction system as a mixed raw material.

[0049] During the reaction, a double decomposition reaction occurs. Specifically, the chloride salts in the molten medium interact with the anhydrous calcium chloride input, and anhydrous aluminum sulfate or gallium sulfate. During this process, the chloride salts and the calcium chloride component of the anhydrous calcium chloride undergo an ion-exchange double decomposition reaction with the anhydrous aluminum sulfate or gallium sulfate. From a chemical perspective, this reaction causes the target metal element to recombine with the chlorine element in the calcium chloride, forming a metal chloride product containing aluminum chloride or gallium chloride. Simultaneously, sulfate ions combine with calcium to produce a waste residue containing calcium sulfate.

[0050] It is worth mentioning that there are strict and scientific requirements for the relationship between the feeding rate v1 of the mixed raw materials and the mass m1 of the molten salt. The two need to satisfy the relationship: v1:m1≥6:100. The setting of this relationship is of great significance. It enables the feeding rate of the mixed raw materials to be dynamically adjusted as the mass of the molten salt changes. When the mass of the molten salt increases, the feeding rate will also increase accordingly, and vice versa. This dynamic adjustment mechanism can effectively promote the double decomposition reaction to proceed more fully. In this way, we can ensure that the reactants can fully contact and react with each other, so as to obtain a sufficient amount of target metal chloride salt and calcium sulfate-containing waste residue. This not only improves the efficiency of the reaction, but also makes the two important reactants, sulfate and anhydrous calcium chloride, have a higher utilization rate, reduces the waste of raw materials, and reduces production costs.

[0051] Furthermore, the temperature of the metathesis reaction is a key factor in this method. In this method, the metathesis reaction temperature is strictly controlled at ≥530°C. This high temperature is determined by the difference between the liquefaction temperature of the calcium chloride-containing chloride salt and the melting temperature of the calcium sulfate waste residue. Since the target metal chloride salt exists in a gaseous state at such high temperatures, while the calcium sulfate-containing waste residue remains solid in the liquid molten salt, this provides a natural advantage in separating the two. This physical difference facilitates the separation of the gaseous target metal chloride salt from the solid calcium sulfate-containing waste residue. In subsequent processing, the gaseous target metal chloride salt is condensed and converted into a high-purity anhydrous metal chloride solid product. This separation and purification method is simple and effective, significantly improving the purity of the final product, ultimately resulting in high-quality anhydrous aluminum chloride or anhydrous gallium chloride anhydrous metal chloride products that meet industrial production and market needs.

[0052] In summary, the embodiments of the present application provide a method for preparing anhydrous metal chloride salts based on a double decomposition reaction. This method achieves the goal of preparing anhydrous metal chloride salts with high efficiency and high purity through a series of scientific methods and means such as the reasonable selection of reaction medium, precise control of feeding rate and reaction temperature, and has broad application prospects and huge economic value.

[0053] In some optional embodiments, the feeding rate v1 of the mixed raw material and the mass m1 of the molten salt satisfy the relationship: v1:m1=(6-65):100, if the unit of v1 is kg / h, the unit of m1 is kg.

[0054] In these embodiments, the feeding rate v1 of the mixed raw material and the mass m1 of the molten salt can satisfy the relationship: v1:m1=(6~65):100, so that the feeding rate of the mixed raw material is more appropriate to allow the double decomposition reaction to proceed fully, thereby improving the utilization rate of calcium chloride and anhydrous aluminum sulfate / infinite gallium sulfate.

[0055] The value of the feeding speed v1 of the mixed raw material can be 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60 or 65.

[0056] In some optional embodiments, the temperature of the metathesis reaction is 530° C. to 700° C., and the time of the metathesis reaction is 0.5 min to 120 min.

[0057] In these embodiments, the temperature of the metathesis reaction can be 530° C. to 700° C., and the time of the metathesis reaction can be 0.5 min to 120 min, so that the metathesis reaction is carried out under conditions of relatively high temperature and sufficient reaction time, so that a metathesis reaction occurs between the chloride salt and the calcium chloride component of anhydrous calcium chloride and the anhydrous sulfate metal salt component of anhydrous aluminum sulfate or anhydrous gallium sulfate, so that the target metal element and the chlorine element of calcium chloride form the target chloride metal salt, and the sulfuric acid and calcium elements form the calcium sulfate-containing waste residue. At the same time, the relatively high temperature metathesis reaction will cause the target chloride metal salt to form a gaseous anhydrous chloride metal salt, so as to facilitate subsequent condensation to obtain a high-purity anhydrous chloride metal salt solid product.

[0058] The temperature of the metathesis reaction can be 530°C, 540°C, 560°C, 570°C, 580°C, 590°C, 600°C, 610°C, 620°C, 630°C, 640°C, 650°C, 650°C, 660°C, 670°C, 680°C, 690°C or 700°C.

[0059] The time for the metathesis reaction can be 0.5 min, 1.0 min, 1.5 min, 2.0 min, 2.5 min, 3.0 min, 3.5 min, 4.0 min, 4.5 min, 5.0 min, 10.0 min, 15.0 min, 20.0 min, 25.0 min, 30.0 min, 35.0 min, 40.0 min, 45.0 min, 50.0 min, 60.0 min, 70.0 min, 80.0 min, 90.0 min, 100.0 min, 110.0 min or 120.0 min.

[0060] In some optional embodiments, the amount n1 of the anhydrous calcium chloride and the amount n2 of the anhydrous metal sulfate satisfy the relationship: n1:n2=(1.45-1.55):1.

[0061] In these embodiments, the amount n1 of anhydrous calcium chloride and the amount n2 of anhydrous metal sulfate can satisfy the relationship: n1:n2=(1.45-1.55):1, so that the raw material anhydrous metal gallium sulfate and anhydrous calcium chloride can fully undergo a double decomposition reaction, so that the target metal element and the chlorine element of the calcium chloride form a metal chloride, and the sulfate ion and the calcium element form a calcium sulfate-containing waste residue, thereby improving the utilization rate of the anhydrous metal sulfate.

[0062] The ratio n1:n2 of the amount n1 of the anhydrous calcium chloride to the amount n2 of the anhydrous metal sulfate can be 1.45:1, 1.46:1, 1.47:1, 1.48:1, 1.49:1, 1.50:1, 1.51:1, 1.52:1, 1.53:1, 1.54:1 or 1.55:1.

[0063] In some optional embodiments, the chloride salt further includes sodium chloride and / or potassium chloride.

[0064] In these embodiments, the chloride salt may further include sodium chloride and / or potassium chloride, so that the chloride salt may contain other conventional chloride salts in addition to calcium chloride, thereby reducing the amount of calcium chloride used and avoiding the use of excessive calcium chloride.

[0065] In some optional embodiments, when the chloride salt includes sodium chloride and calcium chloride, the mass m2 of the sodium chloride and the mass m3 of the calcium chloride satisfy the relationship: m2:m3=1:(1-2); and / or

[0066] When the chloride salt includes sodium chloride, potassium chloride and calcium chloride, the mass of the potassium chloride is 5% to 20% of the total mass of the chloride salt, and the mass m2 of the sodium chloride and the mass m3 of the calcium chloride satisfy the relationship: m2:m3=(2:7) to (1:2).

[0067] In these embodiments, when the chloride salt includes sodium chloride and calcium chloride, the mass m2 of sodium chloride and the mass m3 of calcium chloride can satisfy the relationship: m2:m3=1:(1-2), and when the chloride salt includes sodium chloride, potassium chloride and calcium chloride, the mass of potassium chloride can be 5% to 20% of the total mass of the chloride salt, and the mass m2 of sodium chloride and the mass m3 of calcium chloride can satisfy the relationship: m2:m3=(2:7) to (1:2), so that the chloride salt has sufficient calcium chloride. The chloride salt with sufficient calcium chloride can fully undergo a double decomposition reaction with the anhydrous aluminum sulfate or gallium sulfate of the mixed raw material to obtain a sufficient amount of gaseous anhydrous aluminum chloride or gallium chloride and calcium sulfate-containing waste residue.

[0068] When the chloride salt includes sodium chloride and calcium chloride, the ratio m2:m3 of the mass m2 of sodium chloride to the mass m3 of calcium chloride may be 1:1.0, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2.0.

[0069] In the case where the chloride salt includes sodium chloride, potassium chloride and calcium chloride, the mass of potassium chloride can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20% of the total mass of the chloride salt.

[0070] In the case where the chloride salt includes sodium chloride, potassium chloride and calcium chloride, the mass m2 of sodium chloride and the mass m3 of calcium chloride may satisfy the relationship: m2:m3=2:7, 2:6, 2:5 or 2:4.

[0071] In some optional embodiments, the melting temperature is 530°C to 700°C.

[0072] In these embodiments, the melting temperature can be 530° C. to 700° C., which promotes the conversion of the chloride salt containing calcium chloride from a solid state to a molten liquid. The liquid molten salt can not only serve as a reaction site medium for the metathesis reaction, but also provide sufficient chlorine element for the metathesis reaction to promote the metathesis reaction to proceed fully, thereby improving the utilization rate of the chloride salt and anhydrous calcium chloride.

[0073] The temperature of the melt may be 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, 650°C, or 700°C.

[0074] Figure 2 The following is a schematic diagram showing a detailed process of a method for preparing anhydrous metal chloride salt based on a molten salt medium and a double decomposition reaction provided in an embodiment of the present application;

[0075] In some optional embodiments, the step of subjecting the mixed raw material and the molten salt to a double decomposition reaction to obtain a gaseous anhydrous chloride metal salt comprises the following steps:

[0076] S301. The mixed raw material and the molten salt are subjected to a double decomposition reaction to obtain a gaseous anhydrous chloride metal salt and a calcium sulfate-containing waste residue;

[0077] S302. The calcium sulfate-containing waste residue is crystallized to obtain a waste molten salt containing crystallized calcium sulfate waste residue;

[0078] S303. The waste molten salt containing crystallized calcium sulfate waste residue is separated to obtain crystallized calcium sulfate waste residue and molten salt;

[0079] S304. The crystallized calcium sulfate waste residue is washed and filtered in sequence to obtain a salt-containing filtrate and a calcium sulfate waste residue, respectively;

[0080] S305. The salt-containing filtrate is concentrated and crystallized to obtain a crystal mixture;

[0081] S306. Drying the crystal mixture to obtain anhydrous chloride salt containing calcium chloride.

[0082] In these embodiments, the calcium sulfate-containing waste residue obtained by the double decomposition reaction is crystallized so that the calcium sulfate in the calcium sulfate-containing waste residue forms crystalline calcium sulfate, and then the waste molten salt containing the crystallized calcium sulfate waste residue is separated, and the molten salt containing the crystallized calcium sulfate waste residue can be extracted. Subsequently, the crystallized calcium sulfate waste residue is washed and filtered to obtain pure calcium sulfate waste residue, and finally the salt-containing filtrate is concentrated, crystallized and dried to further recover anhydrous chloride salts, which can be used as molten raw materials to obtain a sufficient amount of molten salt.

[0083] It should be noted that the calcium sulfate waste residue can be used as a building material.

[0084] It should be noted that the separation needs to be carried out in a molten salt filter and a certain temperature must be maintained so that the chloride salt of the waste molten salt can be separated from the crystallized calcium sulfate waste residue in the form of molten salt, thereby obtaining pure molten salt.

[0085] In addition, this washing can be performed using 90 degreeC hot water as a detergent.

[0086] It should be noted that the drying temperature may be 230°C to 250°C.

[0087] In some optional embodiments, the temperature of the crystallization treatment is 520° C. to 680° C., and the time of the crystallization treatment is 30 min to 720 min.

[0088] In these embodiments, the temperature of the crystallization treatment can be 520° C. to 680° C., and the time of the crystallization treatment can be 30 min to 720 min, so that the calcium sulfate containing the calcium sulfate waste residue has enough temperature and enough time to be converted into calcium sulfate crystals, to facilitate the subsequent separation, and to obtain crystallized calcium sulfate waste residue and pure molten salt.

[0089] The temperature of the crystallization treatment may be 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, 610°C, 620°C, 630°C, 640°C, 650°C, 660°C, 670°C or 680°C.

[0090] The crystallization treatment time can be 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 150min, 200min, 250min, 300min, 350min, 400min, 450min, 500min, 550min, 600min, 650min, 700min, 710min or 720min.

[0091] In some optional embodiments, the separation temperature is 500°C to 650°C.

[0092] In these embodiments, the separation temperature can be 500°C to 650°C, so that the waste molten salt containing crystallized calcium sulfate waste residue is separated at a higher temperature, so that the chloride salt of the waste molten salt is separated from the crystallized calcium sulfate waste residue in a molten state, thereby obtaining a molten salt component with higher purity, which is convenient for subsequent recovery of the molten salt component and application in the double decomposition reaction.

[0093] The temperature of the separation may be 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, 610°C, 620°C, 630°C, 640°C or 650°C.

[0094] The present application is further described below with reference to specific examples. Experimental methods in the following examples where specific conditions are not specified are generally measured in accordance with national / industry standards. If there are no corresponding national / industry standards, the methods are carried out in accordance with commonly used international standards, conventional conditions, or conditions recommended by the manufacturer.

[0095] Example 1

[0096] like Figure 2 As shown, a method for preparing anhydrous chloride metal salt based on a molten salt medium and a double decomposition reaction comprises:

[0097] S1. The chloride salt containing calcium chloride is melted to obtain a molten salt;

[0098] S2. Anhydrous calcium chloride and anhydrous metal sulfate are mixed to obtain a mixed raw material; wherein the anhydrous metal sulfate is anhydrous aluminum sulfate;

[0099] S301. The mixed raw material and the molten salt are subjected to a double decomposition reaction to obtain gaseous anhydrous aluminum chloride and calcium sulfate-containing waste residue;

[0100] S302. The calcium sulfate-containing waste residue is crystallized to obtain a waste molten salt containing crystallized calcium sulfate waste residue;

[0101] S303. The waste molten salt containing crystallized calcium sulfate waste residue is separated to obtain crystallized calcium sulfate waste residue and molten salt;

[0102] S304. The crystallized calcium sulfate waste residue is washed and filtered in sequence to obtain a salt-containing filtrate and calcium sulfate waste residue;

[0103] S305. The salt-containing filtrate is concentrated and crystallized to obtain a crystal mixture;

[0104] S306. The crystal mixture is dried to obtain anhydrous chloride salt containing calcium chloride;

[0105] S4. Condensing the gaseous anhydrous aluminum chloride to obtain anhydrous aluminum chloride solid product.

[0106] The feeding rate v1 of the mixed raw material and the mass m2 of the molten salt satisfy the relationship: v1:m1=24:100. If the unit of v1 is kg / h, the unit of m1 is kg.

[0107] The temperature of the metathesis reaction is 580° C., and the time of the metathesis reaction is 5 min.

[0108] The amount of substance n1 of anhydrous calcium chloride and the amount of substance n2 of anhydrous aluminum sulfate satisfy the relationship: n1:n2=1.50:1.00.

[0109] Chlorinated salts also include sodium chloride.

[0110] When the chloride salt includes sodium chloride and calcium chloride, the mass m2 of the sodium chloride and the mass m3 of the calcium chloride satisfy the relationship: m2:m3=1:1.

[0111] The melting temperature is 580°C.

[0112] The temperature of the crystallization treatment is 560° C., and the time of the crystallization treatment is 720 min.

[0113] The separation temperature is 540℃~550℃.

[0114] Example 2

[0115] Compared with Example 1, this embodiment has the following differences, and the rest are the same:

[0116] The feeding rate v1 of the mixed raw material and the mass m1 of the molten salt satisfy the relationship: v1:m1=56:100. If the unit of v1 is kg / h, the unit of m1 is kg.

[0117] The temperature of the metathesis reaction is 690° C., and the time of the metathesis reaction is 0.5 min.

[0118] The amount of substance n1 of anhydrous calcium chloride and the amount of substance n2 of anhydrous aluminum sulfate satisfy the relationship: n1:n2=1.45:1.

[0119] Chlorinated salts also include sodium chloride.

[0120] In the case where the chloride salt includes sodium chloride and calcium chloride, the mass m2 of sodium chloride and the mass m3 of calcium chloride satisfy the relationship: m2:m3=1:2;

[0121] The melting temperature is 690°C.

[0122] The temperature of the crystallization treatment is 680° C., and the time of the crystallization treatment is 120 min.

[0123] The separation temperature is 630℃~650℃.

[0124] Example 3

[0125] Compared with Example 1, this embodiment has the following differences, and the rest are the same:

[0126] The feeding rate v1 of the mixed raw material and the mass m2 of the molten salt satisfy the relationship: v1:m1=42:100. If the unit of v1 is kg / h, the unit of m1 is kg.

[0127] The temperature of the metathesis reaction is 680° C., and the time of the metathesis reaction is 15 min.

[0128] The amount of substance n1 of anhydrous calcium chloride and the amount of substance n2 of anhydrous aluminum sulfate satisfy the relationship: n1:n2=1.48:1.

[0129] Chlorinated salts also include sodium chloride.

[0130] In the case where the chloride salt includes sodium chloride and calcium chloride, the mass m2 of the sodium chloride and the mass m3 of the calcium chloride satisfy the relationship: m2:m3=5:6.

[0131] The melting temperature is 680°C.

[0132] The temperature of the crystallization treatment is 680° C., and the time of the crystallization treatment is 180 min.

[0133] The separation temperature is 640℃~650℃.

[0134] Example 4

[0135] Compared with Example 1, this embodiment has the following differences, and the rest are the same:

[0136] The feeding rate v1 of the mixed raw material and the mass m1 of the molten salt satisfy the relationship: v1:m1=30:100. If the unit of v1 is kg / h, the unit of m1 is kg.

[0137] The temperature of the metathesis reaction is 620° C., and the time of the metathesis reaction is 10 min.

[0138] The amount of substance n1 of anhydrous calcium chloride and the amount of substance n2 of anhydrous aluminum sulfate satisfy the relationship: n1:n2=1.46:1.

[0139] Chlorinated salts also include sodium chloride.

[0140] In the case where the chloride salt includes sodium chloride and calcium chloride, the mass m2 of the sodium chloride and the mass m3 of the calcium chloride satisfy the relationship: m2:m3=4:7.

[0141] The melting temperature is 620°C.

[0142] The temperature of the crystallization treatment is 600° C., and the time of the crystallization treatment is 120 min.

[0143] The separation temperature is 560℃~590℃.

[0144] Example 5

[0145] Compared with Example 1, this embodiment has the following differences, and the rest are the same:

[0146] The feeding rate v1 of the mixed raw material and the mass m1 of the molten salt satisfy the relationship: v1:m1=33:100. If the unit of v1 is kg / h, the unit of m1 is kg.

[0147] The temperature of the metathesis reaction is 600° C., and the time of the metathesis reaction is 20 min.

[0148] The amount of substance n1 of anhydrous calcium chloride and the amount of substance n2 of anhydrous aluminum sulfate satisfy the relationship: n1:n2=1.50:1.

[0149] Chloride salts also include sodium chloride and potassium chloride.

[0150] In the case where the chloride salt includes sodium chloride, potassium chloride and calcium chloride, the mass of potassium chloride is 7% of the total mass of the chloride salt, and the mass m2 of sodium chloride and the mass m3 of calcium chloride satisfy the relationship: m2:m3=1:2.

[0151] The melting temperature is 600°C.

[0152] The temperature of the crystallization treatment is 580° C., and the time of the crystallization treatment is 240 min.

[0153] The separation temperature is 560℃~580℃.

[0154] Example 6

[0155] Compared with Example 1, this embodiment has the following differences, and the rest are the same:

[0156] The feeding rate v1 of the mixed raw material and the mass m2 of the molten salt satisfy the relationship: v1:m1=18:100. If the unit of v1 is kg / h, the unit of m1 is kg.

[0157] The temperature of the metathesis reaction is 550° C., and the time of the metathesis reaction is 120 min.

[0158] The amount n1 of anhydrous calcium chloride and the amount n2 of anhydrous aluminum sulfate satisfy the relationship: n1:n2=(1.45~1.55):1.

[0159] Chloride salts also include sodium chloride and potassium chloride.

[0160] In the case where the chloride salt includes sodium chloride, potassium chloride and calcium chloride, the mass of potassium chloride is 10% of the total mass of the chloride salt, and the mass m2 of sodium chloride and the mass m3 of calcium chloride satisfy the relationship: m2:m3=2:7.

[0161] The melting temperature is 550°C.

[0162] The temperature of the crystallization treatment is 540° C., and the time of the crystallization treatment is 720 min.

[0163] The separation temperature is 530℃~540℃.

[0164] Example 7

[0165] Compared with Example 1, this embodiment has the following differences, and the rest are the same:

[0166] The feeding rate v1 of the mixed raw material and the mass m1 of the molten salt satisfy the relationship: v1:m1=65:100. If the unit of v1 is kg / h, the unit of m1 is kg.

[0167] The temperature of the metathesis reaction is 700° C., and the time of the metathesis reaction is 0.5 min.

[0168] The amount of substance n1 of anhydrous calcium chloride and the amount of substance n2 of anhydrous aluminum sulfate satisfy the relationship: n1:n2=1.49:1.

[0169] Chloride salts also include sodium chloride and potassium chloride.

[0170] In the case where the chloride salt includes sodium chloride, potassium chloride and calcium chloride, the mass of potassium chloride is 15% of the total mass of the chloride salt, and the mass m2 of sodium chloride and the mass m3 of calcium chloride satisfy the relationship: m2:m3=4:13.

[0171] The melting temperature is 700°C.

[0172] The temperature of the crystallization treatment is 650° C., and the time of the crystallization treatment is 720 min.

[0173] The separation temperature is 620℃~640℃.

[0174] Example 8

[0175] Compared with Example 1, this embodiment has the following differences, and the rest are the same:

[0176] The feeding rate v1 of the mixed raw material and the mass m2 of the molten salt satisfy the relationship: v1:m1=36:100. If the unit of v1 is kg / h, the unit of m1 is kg.

[0177] The temperature of the metathesis reaction is 650° C., and the time of the metathesis reaction is 60 min.

[0178] The amount of substance n1 of anhydrous calcium chloride and the amount of substance n2 of aluminum sulfate satisfy the relationship: n1:n2=1.55:1.

[0179] Chloride salts also include sodium chloride and potassium chloride.

[0180] In the case where the chloride salt includes sodium chloride, potassium chloride and calcium chloride, the mass of potassium chloride is 20% of the total mass of the chloride salt, and the mass m2 of sodium chloride and the mass m3 of calcium chloride satisfy the relationship: m2:m3=1:3.

[0181] The melting temperature is 650°C.

[0182] The temperature of the crystallization treatment is 650° C., and the time of the crystallization treatment is 720 min.

[0183] The separation temperature is 520℃~530℃.

[0184] Example 9

[0185] like Figure 2 As shown, a method for preparing anhydrous chloride metal salt based on double decomposition reaction comprises:

[0186] S1. The chloride salt containing calcium chloride is melted to obtain a molten salt;

[0187] S2. Anhydrous calcium chloride and anhydrous metal sulfate are mixed to obtain a mixed raw material; wherein the anhydrous metal sulfate is anhydrous gallium sulfate;

[0188] S3. The mixed raw material and the molten salt are subjected to a double decomposition reaction to make anhydrous calcium chloride and anhydrous gallium sulfate undergo a double decomposition reaction to obtain gaseous anhydrous gallium chloride;

[0189] S301. The mixed raw material and the molten salt are subjected to a double decomposition reaction to make anhydrous calcium chloride and anhydrous gallium sulfate undergo a double decomposition reaction to obtain gaseous anhydrous gallium chloride and calcium sulfate-containing waste residue, respectively;

[0190] S302. The calcium sulfate-containing waste residue is crystallized to obtain a waste molten salt containing crystallized calcium sulfate waste residue;

[0191] S303. The waste molten salt containing crystallized calcium sulfate waste residue is separated to obtain crystallized calcium sulfate waste residue and molten salt;

[0192] S304. The crystallized calcium sulfate waste residue is washed and filtered in sequence to obtain a salt-containing filtrate and calcium sulfate waste residue;

[0193] S305. The salt-containing filtrate is concentrated and crystallized to obtain a crystal mixture;

[0194] S306. The crystal mixture is dried to obtain anhydrous chloride salt containing calcium chloride;

[0195] S4. Condensing the gaseous anhydrous aluminum chloride or gallium chloride to obtain a solid product of anhydrous chloride metal salt.

[0196] The feeding rate v1 of the mixed raw material and the mass m1 of the molten salt satisfy the relationship: v1:m1=12:100. If the unit of v1 is kg / h, the unit of m1 is kg.

[0197] The temperature of the metathesis reaction is 540° C., and the time of the metathesis reaction is 120 min.

[0198] The amount n1 of anhydrous calcium chloride and the amount n2 of anhydrous gallium sulfate satisfy the relationship: n1:n2=1.51:1.

[0199] Chloride salts also include sodium chloride and potassium chloride.

[0200] In the case where the chloride salt includes sodium chloride, potassium chloride and calcium chloride, the mass of potassium chloride is 15% of the total mass of the chloride salt, and the mass m2 of sodium chloride and the mass m3 of calcium chloride satisfy the relationship: m2:m3=4:13.

[0201] The melting temperature is 540°C.

[0202] The temperature of the crystallization treatment is 540° C., and the time of the crystallization treatment is 720 min.

[0203] The separation temperature is 520℃~530℃.

[0204] Example 10

[0205] Compared with Example 9, this embodiment has the following differences, and the rest are the same:

[0206] The feeding rate v1 of the mixed raw material and the mass m1 of the molten salt satisfy the relationship: v1:m1=48:100. If the unit of v1 is kg / h, the unit of m1 is kg.

[0207] The temperature of the metathesis reaction is 580° C., and the time of the metathesis reaction is 20 min.

[0208] The amount n1 of anhydrous calcium chloride and the amount n2 of anhydrous gallium sulfate satisfy the relationship: n1:n2=1.50:1.00.

[0209] Chloride salts also include sodium chloride and potassium chloride.

[0210] In the case where the chloride salt includes sodium chloride, potassium chloride and calcium chloride, the mass of potassium chloride is 10% of the total mass of the chloride salt, and the mass m2 of sodium chloride and the mass m3 of calcium chloride satisfy the relationship: m2:m3=5:13.

[0211] The melting temperature is 580°C.

[0212] The temperature of the crystallization treatment is 550° C., and the time of the crystallization treatment is 180 min.

[0213] The separation temperature is 530℃~540℃.

[0214] Example 11

[0215] Compared with Example 9, this embodiment has the following differences, and the rest are the same:

[0216] The feeding rate v1 of the mixed raw material and the mass m1 of the molten salt satisfy the relationship: v1:m1=6:100. If the unit of v1 is kg / h, the unit of m1 is kg.

[0217] The temperature of the metathesis reaction is 530° C., and the time of the metathesis reaction is 60 min.

[0218] The amount n1 of anhydrous calcium chloride and the amount n2 of anhydrous gallium sulfate satisfy the relationship: n1:n2=1.47:1.00.

[0219] Chloride salts also include sodium chloride and potassium chloride.

[0220] In the case where the chloride salt includes sodium chloride, potassium chloride and calcium chloride, the mass of potassium chloride is 10% of the total mass of the chloride salt, and the mass m2 of sodium chloride and the mass m3 of calcium chloride satisfy the relationship: m2:m3=2:7.

[0221] The melting temperature is 530°C.

[0222] The temperature of the crystallization treatment is 520° C., and the time of the crystallization treatment is 120 min.

[0223] The separation temperature is 500℃~520℃.

[0224] Example 12

[0225] Compared with Example 9, this embodiment has the following differences, and the rest are the same:

[0226] The feeding rate v1 of the mixed raw material and the mass m2 of the molten salt satisfy the relationship: v1:m1=45:100. If the unit of v1 is kg / h, the unit of m1 is kg.

[0227] The temperature of the metathesis reaction is 630° C., and the time of the metathesis reaction is 0.5 min.

[0228] The amount n1 of anhydrous calcium chloride and the amount n2 of anhydrous aluminum sulfate or gallium sulfate satisfy the relationship: n1:n2=1.55:1.

[0229] Chlorinated salts also include sodium chloride.

[0230] In the case where the chloride salt includes sodium chloride and calcium chloride, the mass m2 of the sodium chloride and the mass m3 of the calcium chloride satisfy the relationship: m2:m3=1:1.

[0231] The melting temperature is 630°C.

[0232] The temperature of the crystallization treatment is 580° C., and the time of the crystallization treatment is 720 min.

[0233] The separation temperature is 560℃~580℃.

[0234] Comparative Example 1

[0235] Traditional preparation method of anhydrous aluminum chloride 1:

[0236] A mixed electrolyte was prepared using 76.7 kg of NaCl and 179.33 kg of AlCl3;

[0237] The mixed electrolyte was heated to 830°C, and then 76.8 kg of carbon and 76.8 kg of aluminum oxide were added to the mixed electrolyte. Under continuous stirring, carbon powder with a particle size of less than 100 mesh and industrial aluminum oxide were added to the electrolyte at a feeding rate of 9.44 kg / h and 52.8 kg / h, respectively. At the same time, chlorine gas was introduced at a rate of 111 kg / h to obtain gaseous aluminum chloride.

[0238] The gaseous aluminum chloride is purified by condensation-sublimation method to obtain gaseous aluminum chloride product.

[0239] The production of gaseous aluminum chloride products using this preparation method can reach 138 kg / h, the total circulating mass of aluminum chloride and NaCl in the chlorination process can reach 365 kg / h, the purity of gaseous aluminum chloride after purification by condensation-sublimation method can reach 99%, and the utilization rate of the chlorinating agent can reach 99%.

[0240] Comparative Example 2

[0241] Traditional preparation method 2 of anhydrous aluminum chloride: 390g of NaCl and 920g of AlCl3 are used to prepare a mixed salt;

[0242] The mixed salt was heated to 788°C, and then 325g of coke with a particle size of less than 100 mesh, 1g of copper chloride, and 50g of aluminum oxide were added respectively, and the coke was introduced at a rate of 300mL / min (standard state) to react to obtain gaseous products;

[0243] The gaseous product is sequentially condensed and recovered and sublimed for purification to obtain anhydrous aluminum chloride product with a purity of 98%.

[0244] The chlorine conversion rate of this method can reach 83%.

[0245] Comparative Example 3

[0246] A method for preparing high-purity anhydrous aluminum chloride comprises the following steps:

[0247] (1) Alumina is used as a raw material, carbon monoxide is used as a carbon source, and biomass carbon is used as a supplementary carbon source, ensuring that the mass ratio of carbon monoxide and carbon in biomass carbon:alumina is 0.1:1, and the particle size ratio of alumina to supplementary biomass carbon is 1:5, and these raw materials are mixed to obtain a uniformly mixed mixed raw material.

[0248] (2) The uniformly mixed raw materials are added to a stirred fluidized bed through a side stirring shaft for chlorination. The reaction temperature of the chlorination process is 500°C, the reaction time is 120 minutes, and the ratio of oxygen to chlorine is 0.05:1. The principle of the chlorination reaction is: Al2O3+1.5C+3Cl2=2AlCl3+1.5CO2 or Al2O3+3C+3Cl2=2AlCl3+3CO, to obtain gaseous aluminum chloride;

[0249] (3) Stirred agglomeration fluidized bed, the angle between the side agitator shaft and the furnace body is 45°, the stirring speed is 50 rpm, and the top agitator speed is 40 rpm. Compared with the traditional fluidized bed, the large bubble rate of the stirred agglomeration fluidized bed is reduced by 65%, the heat transfer efficiency is increased by 30%, and the dust rate is reduced by 1%;

[0250] (4) using a condenser to condense gaseous aluminum chloride to obtain anhydrous aluminum chloride, carbon dioxide and chlorine; the condenser adopts a screw propeller condenser, the condensation temperature is controlled to be 150°C, the screw propeller condenser and the screw propeller stirring speed is 10rpm, the aluminum chloride is pushed out from the discharge air lock, and the discharged aluminum chloride is packaged, so that the separation efficiency of the flue gas of gaseous aluminum chloride and anhydrous aluminum chloride is 99%, and the water content of anhydrous aluminum chloride is 0.1%;

[0251] (5) The discharged carbon dioxide and chlorine are compressed and separated, and the chlorine is returned to the chlorination section for use as a chlorine source. The carbon dioxide can react with the biomass carbon to produce carbon monoxide, which can be returned to the chlorination section for use as a carbon source. The gas-solid reaction temperature is 700°C, the gas-solid reaction time is 10 minutes, the carbon residue in the biomass carbon after the gas-solid reaction is 0.05wt%, and the mass fraction of carbon monoxide in the resulting flue gas is 80%. After treatment by this method, the chlorination efficiency of aluminum oxide is 95%; after separation and purification of the gas phase product, anhydrous aluminum chloride with a mass fraction of 99.9% is obtained.

[0252] Comparative Example 4

[0253] A method for producing high-purity aluminum chloride by utilizing crystallized aluminum chloride comprises the following steps:

[0254] (1) 400 g of triethanolamine was added to a reactor, the temperature of the reactor was controlled at 40° C., and 271 g of industrial hydrochloric acid with a mass concentration of 36% was slowly added to the reactor while stirring, and the mixture was reacted for 4 h to obtain a mixed slurry; the mixed slurry was filtered to obtain a crude organic hydrochloride; the crude organic hydrochloride was washed twice with anhydrous ethanol, and then dried in a drying oven at 50° C. for 6 h to obtain an organic hydrochloride. The purity of the organic hydrochloride was found to be 98.2% after testing;

[0255] (2) adding 241.5 g of crystalline aluminum chloride to the reaction crystallization kettle, slowly heating the temperature to 90° C., then adding 3.6 g of water and stirring to fully dissolve the crystalline aluminum chloride, then taking 185.6 g of the organic hydrochloride obtained in step (1) and adding it to the reaction crystallization kettle, stirring and dissolving until it becomes a homogeneous phase, and then naturally cooling to room temperature to obtain crystals; placing the obtained crystals in a drying oven at 100° C. for 8 h to obtain about 402 g of a composite salt component; (3) placing the 402 g of the composite salt component obtained in step (2) in a fluidized bed reactor, and heating the reactor to 160° C. for fluidized reaction for 30 min to obtain 285 g of triethanolamine aluminum chloride complex salt without crystal water; then placing the obtained triethanolamine aluminum chloride complex salt in another fluidized bed reactor, reacting at 220° C. for 20 min, while capturing the volatilized aluminum chloride gas to obtain 120.5 g of anhydrous aluminum chloride. The purity of the anhydrous aluminum chloride was tested to be 98.7%, and the conversion rate of the raw material crystalline aluminum chloride was 93%.

[0256] Comparative Example 5

[0257] Traditional aluminum chloride preparation method:

[0258] A metal aluminum ingot is added into a chlorination furnace, which is then heated to 800° C., and chlorine gas is subsequently introduced at a rate of 3 kg / kg to 12 kg / kg of aluminum per hour to carry out a chlorination reaction on the metal aluminum ingot to obtain gaseous aluminum chloride. The obtained gaseous aluminum chloride is then condensed and collected to obtain an anhydrous aluminum chloride product with a purity of 99.6%. The utilization rate of the raw chlorine gas is 95%, and the utilization rate of the raw metal aluminum is 98%.

[0259] Comparative Example 6

[0260] Compared with Example 1, this comparative example has the following differences, and the rest are the same:

[0261] The feeding rate v1 of the mixed raw material and the mass m1 of the molten salt satisfy the relationship: v1:m1=4:100. If the unit of v1 is kg / h, the unit of m1 is kg.

[0262] Related experiments and effect data:

[0263] The purity of the solid products of anhydrous metal chloride salts and the utilization rate of raw materials obtained in each embodiment and comparative example were statistically analyzed, and the results are shown in Table 1.

[0264] Table 1 Purity of solid products of anhydrous metal chloride and utilization rate of raw materials of various embodiments and comparative examples

[0265]

[0266] As can be seen from Table 1, the embodiment of the present application provides a method for preparing anhydrous metal chloride salt based on double decomposition reaction. This method can improve the purity of the solid product of anhydrous metal chloride salt to 97.0% or more, and the utilization rate of the raw material anhydrous metal sulfate salt to 98% or more by a series of scientific methods and means such as reasonable selection of reaction medium, precise control of feeding rate and reaction temperature.

[0267] In addition, compared with Example 1, Comparative Example 6 uses a slower feeding rate V1. Although the purity and recovery rate of the anhydrous metal chloride product are higher, under the same aluminum chloride production conditions, Comparative Example 6 needs to recycle more calcium chloride-containing molten salt medium, thereby increasing the energy consumption and cost per unit product.

[0268] In summary, the embodiments of the present application provide a method for preparing anhydrous chloride metal salts based on a molten salt medium and a double decomposition reaction. This method comprehensively selects the reaction medium, and controls the feeding rate and the double decomposition reaction temperature, etc., which can achieve a simultaneous improvement in the utilization rate of the chlorinating agent and the purity of the product.

[0269] In addition, the embodiments of the present application provide a method for preparing anhydrous metal chloride salt based on a molten salt medium and a double decomposition reaction. The method is based on a molten salt state as a whole, without the intervention of any water, and can inhibit the hydrolysis of the solid product of the anhydrous metal chloride salt. Therefore, the solid product of the anhydrous metal chloride salt prepared by this method has a high purity.

[0270] In addition, an embodiment of the present application provides a method for preparing anhydrous chloride metal salt based on a molten salt medium and a double decomposition reaction. This method sequentially performs crystallization treatment and separation on the obtained calcium sulfate-containing waste residue, which can effectively improve the filtration performance of the solid calcium sulfate waste residue and effectively separate the molten salt and the calcium sulfate waste residue, thereby realizing efficient recycling of the molten salt raw material.

[0271] In addition, the embodiment of the present application provides a method for preparing anhydrous chloride metal salts based on a double decomposition reaction. The method is based on a double decomposition reaction as a whole, which makes the process of the method simple; in addition, the method mainly uses calcium chloride and anhydrous aluminum sulfate or gallium sulfate as raw materials. The method is easy to purify and refine, has low cost, and is easy to scale production.

[0272] In addition, the embodiment of the present application provides a method for preparing anhydrous metal chloride salts based on a molten salt medium and a double decomposition reaction. The key process sections of this method can be interconnected with solar thermal energy storage technology to achieve low-carbon and green production of solid-state anhydrous metal chloride salt products.

[0273] The foregoing is merely a detailed description of the present invention, intended to enable those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein, but rather is intended to conform to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing anhydrous metal chloride salt based on a molten salt medium and a double decomposition reaction, wherein the metal chloride salt includes aluminum chloride or gallium chloride, the method comprising: melting a chloride salt containing calcium chloride to obtain a molten salt; Mixing anhydrous calcium chloride and anhydrous metal sulfate to obtain a mixed raw material; wherein the anhydrous metal sulfate includes anhydrous aluminum sulfate or anhydrous gallium sulfate; The mixed raw material and the molten salt are subjected to a double decomposition reaction to obtain a gaseous anhydrous chloride metal salt; wherein the feeding rate v1 of the mixed raw material and the mass m1 of the molten salt satisfy the relationship: v1:m1≥6:100, if the unit of v1 is kg / h, the unit of m1 is kg; the temperature of the double decomposition reaction is ≥530°C; The gaseous anhydrous metal chloride salt is condensed to obtain an anhydrous metal chloride salt solid product.

2. The method according to claim 1, wherein the feeding rate v1 of the mixed raw material and the mass m1 of the molten salt satisfy the relationship: v1:m1=(6-65):100, and if the unit of v1 is kg / h, the unit of m1 is kg.

3. The method according to claim 1, wherein the temperature of the metathesis reaction is 530°C to 700°C, and the time of the metathesis reaction is 0.5 min to 120 min.

4. The method according to claim 1, wherein the amount n1 of the anhydrous calcium chloride and the amount n2 of the anhydrous metal sulfate satisfy the relationship: n1:n2=(1.45-1.55):

1.

5. The method according to claim 1, wherein the chloride salt further comprises sodium chloride and / or potassium chloride.

6. The method according to claim 5, wherein the mass m2 of the sodium chloride and the mass m3 of the calcium chloride satisfy the relationship: m2:m3=1:(1-2); and / or When the chloride salt includes sodium chloride, potassium chloride and calcium chloride, the mass of the potassium chloride is 5% to 20% of the total mass of the chloride salt, and the mass m2 of the sodium chloride and the mass m3 of the calcium chloride satisfy the relationship: m2:m3=(2:7) to (1:2). The method according to claim 1 , wherein the melting temperature is 530° C. to 700° C.

8. The method according to claim 1, wherein the mixed raw material and the molten salt are subjected to a double decomposition reaction to obtain a gaseous anhydrous chloride metal salt, comprising the steps of: The mixed raw material and the molten salt are subjected to a double decomposition reaction to obtain a gaseous anhydrous chloride metal salt and a calcium sulfate-containing waste residue, respectively; crystallizing the calcium sulfate-containing waste residue to obtain a waste molten salt containing crystallized calcium sulfate waste residue; Separating the waste molten salt containing crystallized calcium sulfate waste residue to obtain crystallized calcium sulfate waste residue and molten salt; washing and filtering the crystallized calcium sulfate waste residue in sequence to obtain a salt-containing filtrate and calcium sulfate waste residue, respectively; Concentrating and crystallizing the salt-containing filtrate to obtain a crystal mixture; The crystal mixture is dried to obtain anhydrous chloride salt containing calcium chloride. 9 . The method according to claim 8 , wherein the temperature of the crystallization treatment is 520° C. to 680° C., and the time of the crystallization treatment is 30 min to 720 min.

10. The method according to claim 8, wherein the separation temperature is 500°C to 650°C.

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