Resource utilization method of waste aluminum electrolyte

Abstract

The invention relates to a resource utilization method of waste aluminum electrolyte, and belongs to the technical field of aluminum electrolysis waste residue recovery. The method comprises the following steps: obtaining a mixed preparation material of waste aluminum electrolyte and dolomite calcined dolomite; calcining the mixed preparation material of the waste aluminum electrolyte and the dolomite calcined dolomite at a set temperature to obtain a calcined material; mixing the calcined material with an aluminum-silicon reducing agent to obtain a first mixture; the first mixture is pressed, and pellets to be treated are obtained; carrying out vacuum reduction on the to-be-treated pellets to generate mixed metal gas containing lithium, magnesium and sodium; and the mixed metal gas is subjected to segmented crystallization, and the magnesium-lithium alloy and the metal sodium are obtained. According to the method, maximum utilization of valuable metal resources in the waste aluminum electrolyte is realized while magnesium smelting is realized.

Description

Technical Field

[0001] The present application relates to the technical field of aluminum electrolysis waste slag recovery, and in particular to a method for resource utilization of waste aluminum electrolytes. Background Art

[0002] Waste aluminum electrolyte is the waste residue produced in the process of aluminum electrolysis, mainly composed of cryolite, aluminum fluoride and other metal fluorides, which is a large amount of hazardous waste that needs to be treated urgently. At present, the treatment and disposal of these waste aluminum electrolyte residues are still stored and piled up, or simply treated to become industrial waste. Waste aluminum electrolyte contains a certain amount of lithium, sodium, etc., which is a potential resource.

[0003] At present, the main extraction technologies of lithium elements in waste aluminum electrolytes are divided into: acid method, alkaline leaching method, mixed salt roasting leaching method, acid-salt leaching combined method, roasting-water leaching method, etc., mainly through various leaching methods to extract lithium. However, there are few reports on the extraction of the main element sodium metal, so there is an urgent need for a method to maximize the utilization of valuable metal resources in waste aluminum electrolytes. Summary of the invention

[0004] The present application provides a method for resource utilization of waste aluminum electrolyte to solve the following technical problem: how to maximize the utilization of valuable metal resources in waste aluminum electrolyte.

[0005] In a first aspect, the present application provides a method for resource utilization of waste aluminum electrolyte, the method comprising:

[0006] Obtaining a mixed preparation of waste aluminum electrolyte and calcined dolomite;

[0007] Calcining the mixed prepared material of the waste aluminum electrolyte and dolomite calcined white at a set temperature to obtain a calcined material;

[0008] Mixing the calcined material with an aluminum-silicon reducing agent to obtain a first mixed material;

[0009] Pressing the first mixed material to obtain pellets to be processed;

[0010] The pellets to be treated are subjected to vacuum reduction to generate a mixed metal gas containing lithium, magnesium and sodium; and

[0011] The mixed metal gas is subjected to segmented crystallization to obtain a magnesium-lithium alloy and metallic sodium.

[0012] Optionally, the set temperature is 1000°C to 1200°C.

[0013] Optionally, the calcination time is 30 min to 120 min.

[0014] Optionally, the weight ratio of the waste aluminum electrolyte to the dolomite white is 1:(4-8).

[0015] Optionally, the weight ratio of the calcined material to the aluminum silicon reducing agent is 1:(0.2-0.3).

[0016] Optionally, the pressing pressure is 100Mpa to 200Mpa.

[0017] Optionally, the process parameters of the vacuum reduction include: vacuum degree ≤5Pa, temperature 1000°C ~ 1150°C.

[0018] Optionally, the weight ratio of aluminum to silicon in the aluminum-silicon reducing agent is (9-50):1.

[0019] Optionally, the mixed preparation of waste aluminum electrolyte and dolomite calcined white comprises:

[0020] Mixing and grinding the waste aluminum electrolyte and calcined dolomite to obtain a second mixed material;

[0021] The second mixed material is pre-pressed to obtain a mixed pre-material of waste aluminum electrolyte and dolomite calcined white.

[0022] Optionally, the pre-pressing pressure is 10 MPa to 20 MPa.

[0023] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0024] The method for resource utilization of waste aluminum electrolyte provided in an embodiment of the present application comprises: obtaining a mixed preparation of waste aluminum electrolyte and calcined dolomite; calcining the mixed preparation of waste aluminum electrolyte and calcined dolomite at a set temperature to obtain a calcined material; mixing the calcined material with an aluminum-silicon reducing agent to obtain a first mixed material; pressing the first mixed material to obtain a pellet to be processed; vacuum reducing the pellet to be processed to generate a mixed metal gas containing lithium, magnesium and sodium; and segmentally crystallizing the mixed metal gas to obtain a magnesium-lithium alloy and metallic sodium. The mixed preparation of waste aluminum electrolyte and calcined dolomite is calcined at a set temperature. During the calcination process, LiNa2AlF6 and Na2LiAlF6 in the waste aluminum electrolyte react chemically to generate Na3AlF6, NaAlF4 and LiF; then LiF reacts chemically with the calcium oxide in the calcined dolomite to generate Li2O and CaF2 which are easy to reduce and extract, and Na3AlF6 and NaAlF4 react chemically with the calcium oxide in the calcined dolomite to generate Na2O and CaF2, thereby realizing the reduction of the waste aluminum electrolyte. The difficult-to-refine valuable metals Li and Na are converted into Li2O and Na2O that are easy to reduce and extract, and fluorine is fixed at the same time; the first mixed material containing the calcined material and the aluminum-silicon reducing agent is pressed, so that the calcined material and the aluminum-silicon reducing agent are fully in contact, and the compactness of the first mixed material is adjusted, so that the reduced gas can overflow from the first mixed material during the vacuum reduction of the pellets to be treated, and a mixed metal gas containing lithium, magnesium and sodium is fully obtained; the mixed metal gas containing lithium, magnesium and sodium is obtained through segmented crystallization due to the different physical properties of the metals, and magnesium-lithium alloy and metallic sodium are obtained. In summary, the maximum utilization of valuable metal resources in waste aluminum electrolytes is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] 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.

[0026] 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 paying any creative labor.

[0027] Figure 1 A schematic flow chart of a method for resource utilization of waste aluminum electrolyte provided in an embodiment of the present application. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0029] 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 herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0030] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present specification, the terms "including", "comprising", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In the proportional relationship involved in this article, the parameters that need to be described by the ratio should be understood as the antecedent of the proportional formula in the order of description, and the proportional numbers are understood as the latter of the proportional formula. For example, the mass ratio of substance A, substance B and substance C is 1:2:3, then substance A, substance B and substance C should correspond to the proportional numbers in the proportional formula in the order of description, that is, the mass of substance A: the mass of substance B: the mass of substance C = 1:2:3.

[0031] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0032] Waste aluminum electrolyte is the waste slag produced in the process of aluminum electrolysis. It is mainly composed of cryolite, aluminum fluoride and other metal fluorides. It is a large amount of hazardous waste that needs to be treated urgently. At present, the treatment and disposal method of these aluminum electrolyte waste slag is still storage and accumulation, or only simple treatment to become industrial waste. Waste aluminum electrolyte contains a certain amount of lithium, sodium, etc., and is a potential resource. At present, the main extraction technologies of lithium elements in waste aluminum electrolytes are divided into: acid method, alkaline leaching method, mixed salt roasting leaching method, acid-salt leaching combined method, roasting-water leaching method, etc., mainly through various leaching methods to extract lithium. There are few reports on the extraction of the main element metallic sodium.

[0033] Magnesium is considered to be the metal material with the most obvious lightweight effect, among which magnesium-lithium alloy is the lightest metal structural material in the world. Using magnesium-lithium alloy instead of aluminum alloy can achieve a weight reduction effect of 20% to 40%. This feature makes magnesium-lithium alloy an ideal choice for lightweighting in aerospace, weaponry and other fields. At present, magnesium-lithium alloy is formed by adding metallic lithium during the magnesium smelting process. This method has a large loss of metallic lithium due to volatilization and is relatively expensive. Therefore, this application proposes a technical idea for the synergistic extraction of valuable metals from waste aluminum electrolyte and dolomite calcination, so as to maximize the utilization of valuable metal resources in waste aluminum electrolyte while smelting magnesium.

[0034] In a first aspect, the present application provides a method for resource utilization of waste aluminum electrolyte. Figure 1 A schematic diagram of a method for resource utilization of waste aluminum electrolyte provided in an embodiment of the present application; see Figure 1 , the method comprising:

[0035] S1, obtaining a mixed preparation of waste aluminum electrolyte and calcined dolomite;

[0036] In some embodiments, the preparation of the mixed material of waste aluminum electrolyte and dolomite calcined white comprises:

[0037] Mixing and grinding the waste aluminum electrolyte and calcined dolomite to obtain a second mixed material;

[0038] The second mixed material is pre-pressed to obtain a mixed pre-material of waste aluminum electrolyte and dolomite calcined white.

[0039] In some embodiments, the pre-pressing pressure is 10 MPa to 20 MPa.

[0040] In the embodiment of the present application, the waste aluminum electrolyte is the waste slag produced during the aluminum electrolysis process, mainly composed of cryolite, aluminum fluoride and other metal fluorides, etc., containing valuable metals lithium (Li) and sodium (Na). Dolomite is a common carbonate mineral, and its chemical formula is CaMg(CO3)2. Calcined dolomite refers to dolomite after high-temperature calcination. The main chemical reaction of dolomite during the calcination process is CaMg(CO3)2→CaO+MgO+2CO2↑, so the main components of calcined dolomite include: CaO, MgO. The process conditions of the high-temperature calcination include: calcination temperature of 1100℃~1200℃, calcination time of 60min~120min. The waste aluminum electrolyte is mixed and ground with the calcined dolomite, so that the waste aluminum electrolyte and the calcined dolomite are fully mixed and evenly, and the contact area between the two is increased. The end point particle size of the grinding can be ≤150μm. The second mixed material is pre-pressed, and the pre-pressing pressure can be 10Mpa to 20Mpa, which increases the contact area between the waste aluminum electrolyte and the dolomite calcined white, and improves the reaction efficiency of the subsequent mixed preparation of the waste aluminum electrolyte and the dolomite calcined white during the calcination process. Exemplarily, the pre-pressing pressure can be 10Mpa, 12Mpa, 14Mpa, 16Mpa, 18Mpa, 20Mpa, etc.

[0041] S2, calcining the mixed prepared material of the waste aluminum electrolyte and dolomite calcined white at a set temperature to obtain a calcined material;

[0042] In some embodiments, the set temperature is 1000°C to 1200°C.

[0043] In the embodiment of the present application, the mixed preparation of waste aluminum electrolyte and dolomite calcined white is calcined at a set temperature. During the calcination process, LiNa2AlF6 and Na2LiAlF6 in the waste aluminum electrolyte react chemically to generate Na3AlF6, NaAlF4 and LiF; then LiF reacts chemically with the calcium oxide of dolomite calcined white to generate Li2O and CaF2 that are easy to reduce and extract, and Na3AlF6 and NaAlF4 react chemically with the calcium oxide of dolomite calcined white to generate Na2O and CaF2, thereby realizing the conversion of the difficult-to-extract valuable metals Li and Na in the waste aluminum electrolyte into Li2O and Na2O that are easy to reduce and extract, and simultaneously performing fluorine fixation. The specific chemical reactions that occur during the calcination process are:

[0044] LiNa2AlF6+Na2LiAlF6=Na3AlF6+NaAlF4+2LiF;

[0045] 2Na3AlF6+6CaO=3Na2O+6CaF2+Al2O3; 2NaAlF4+4CaO=Na2O+4CaF2+Al2O3;

[0046] 2LiF+CaO=Li2O+CaF2; the set temperature can be 1000℃~1200℃, which can fully realize the conversion of the difficult-to-extract valuable metal elements in the waste aluminum electrolyte into easy-to-extract ones while performing fluorine fixation. Exemplarily, the set temperature can be 1000℃, 1010℃, 1020℃, 1030℃, 1040℃, 1050℃, 1060℃, 1070℃, 1080℃, 1090℃, 1200℃, etc.

[0047] In some embodiments, the calcination time is 30 min to 120 min.

[0048] In the embodiment of the present application, the calcination time can be 30min to 120min, which can better match the above-mentioned set temperature, thereby achieving a better calcination effect. Exemplarily, the calcination time can be 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min, 120min, etc.

[0049] In some embodiments, the weight ratio of the waste aluminum electrolyte to the dolomite white is 1:(4-8).

[0050] In the embodiment of the present application, the weight ratio of the waste aluminum electrolyte to the calcined dolomite can be 1:(4-8), which can enable the calcium in the calcined dolomite to fix the fluorine in the waste aluminum electrolyte and achieve a good fluorine fixation effect. Exemplarily, the weight ratio of the waste aluminum electrolyte to the calcined dolomite can be 1:4, 1:5, 1:6, 1:7, 1:8, etc.

[0051] S3, mixing the calcined material with an aluminum-silicon reducing agent to obtain a first mixed material;

[0052] In some embodiments, the weight ratio of the calcined material to the aluminum silicon reducing agent is 1:(0.2-0.3).

[0053] In the embodiment of the present application, the weight ratio of the calcined material to the aluminum silicon reducing agent can be 1:(0.2-0.3), which can fully extract the magnesium, lithium and sodium elements in the calcined material. Exemplarily, the weight ratio of the calcined material to the aluminum silicon reducing agent can be 1:0.2, 1:0.22, 1:0.23, 1:0.24, 1:0.25, 1:0.26, 1:0.27, 1:0.28, 1:0.29, 1:0.3, etc. In addition, the aluminum silicon reducing agent can be an aluminum silicon alloy or a mixture of aluminum powder and silicon powder.

[0054] In some embodiments, the weight ratio of aluminum to silicon in the aluminum-silicon reducing agent is (9-50):1.

[0055] In the embodiments of the present application, the weight ratio of aluminum to silicon in the aluminum-silicon reducing agent is (9-50):1. By regulating the ratio of aluminum to silicon in the aluminum-silicon reducing agent, more stable 12CaO·7Al2O3, 3CaO·Al2O3·3SiO2 can be formed, and the reduction reaction temperature can be lowered to improve the recovery rate of valuable metals.

[0056] S4, pressing the first mixed material to obtain pellets to be processed;

[0057] In some embodiments, the pressing pressure is 100 MPa to 200 MPa.

[0058] In the embodiment of the present application, the first mixed material containing the calcined material and the aluminum silicon reducing agent is pressed at a pressure of 100Mpa to 200Mpa, so that the calcined material and the aluminum silicon reducing agent are fully contacted, and the compactness of the first mixed material is adjusted, so that the reduced gas can overflow from the first mixed material during the vacuum reduction of the pellets to be processed, and the mixed metal gas containing lithium, magnesium and sodium can be fully obtained. Exemplarily, the pressure can be 100Mpa, 110Mpa, 120Mpa, 130Mpa, 140Mpa, 150Mpa, 160Mpa, 170Mpa, 180Mpa, 190Mpa, 200Mpa, etc.

[0059] S5, subjecting the pellets to be treated to vacuum reduction to generate a mixed metal gas containing lithium, magnesium and sodium; and

[0060] In some embodiments, the process parameters of the vacuum reduction include: vacuum degree ≤ 5 Pa, temperature 1000° C. to 1150° C.

[0061] In an embodiment of the present application, the pellets to be treated are subjected to vacuum reduction to simultaneously extract lithium, magnesium and sodium. The specific chemical reactions occurring during the vacuum reduction process are: 12CaO+21MgO+14Al=21Mg+12CaO·7Al2O3; 3Na2O+2Al=6Na+7Al2O3; 9Li2O+3CaO+2Al+3Si=18Li+3CaO·Al2O3·3SiO2. The vacuum degree of vacuum reduction can be ≤5Pa, which can reduce the reduction reaction temperature and improve the efficiency of the reduction reaction. The temperature of vacuum reduction can be 1000℃~1150℃, driving the reduction reaction and making the reduction reaction sufficient. Exemplarily, the vacuum degree of vacuum reduction can be 5Pa, 4Pa, 3Pa, etc.; the temperature of vacuum reduction can be 1000℃, 1100℃, 1200℃, 1300℃, 1400℃, 1500℃, etc. In addition, the time of vacuum reduction can be 30min~60min.

[0062] S6. Performing segmented crystallization on the mixed metal gas to obtain a magnesium-lithium alloy and metallic sodium.

[0063] In the embodiment of the present application, the mixed metal gas containing lithium, magnesium and sodium is crystallized in stages according to the difference in condensation temperature due to the different physical properties of the metals, thereby obtaining magnesium-lithium alloy and metallic sodium.

[0064] In summary, the method for resource utilization of waste aluminum electrolyte provided in the embodiment of the present application has the following advantages:

[0065] 1. Maximizing the utilization of resources: Through the above-mentioned set of process steps, valuable metals such as lithium and sodium, which were originally difficult to extract and in complex chemical forms in waste aluminum electrolytes, are successfully extracted and converted into valuable magnesium-lithium alloys and metallic sodium, avoiding the waste of these valuable metal resources, improving the overall utilization efficiency of resources, and realizing the maximum utilization of valuable metal resources in waste aluminum electrolytes while refining magnesium;

[0066] 2. Environmental benefits: The fluorine fixation during the calcination process reduces the risk of environmental pollution caused by fluorine in subsequent process links, which is in line with the concept of green environmental protection and sustainable development, so that the entire resource utilization process not only achieves economic benefits, but also takes into account environmental benefits.

[0067] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for the unrecorded specific conditions in the following examples are usually measured according to national standards. If there is no corresponding national standard, then carry out according to general international standards, normal conditions or according to the conditions recommended by the manufacturer.

[0068] Example 1

[0069] A method for resource utilization of waste aluminum electrolyte, comprising:

[0070] Obtaining a mixed pre-material of waste aluminum electrolyte and calcined dolomite, comprising: mixing and grinding the waste aluminum electrolyte and calcined dolomite to obtain a second mixed material; wherein the end point particle size of the grinding is ≤150 μm; pre-pressing the second mixed material to obtain a mixed pre-material of waste aluminum electrolyte and calcined dolomite; wherein the pre-pressing pressure is 20 MPa; and the weight ratio of the waste aluminum electrolyte to the calcined dolomite is 1:4;

[0071] At a set temperature, the mixed preparation of waste aluminum electrolyte and dolomite calcined white is calcined to obtain a calcined material; wherein the set temperature is 1000°C and the calcination time is 120 minutes;

[0072] The calcined material is mixed with an aluminum silicon reducing agent to obtain a first mixed material; wherein the weight ratio of the calcined material to the aluminum silicon reducing agent is 1:0.3, the aluminum silicon reducing agent is an aluminum silicon alloy, and the weight ratio of aluminum to silicon in the aluminum silicon alloy is 9:1.

[0073] The first mixed material is pressed to obtain pellets to be processed; wherein the pressing pressure is 150 MPa;

[0074] subjecting the pellets to be treated to vacuum reduction to generate a mixed metal gas containing lithium, magnesium and sodium; and,

[0075] The mixed metal gas is crystallized in sections to obtain a magnesium-lithium alloy and metallic sodium; wherein the vacuum degree of the vacuum reduction is 3 Pa; the temperature of the vacuum reduction is 1100° C., and the time of the vacuum reduction is 50 minutes.

[0076] Example 2

[0077] A method for resource utilization of waste aluminum electrolyte, comprising:

[0078] Obtaining a mixed pre-material of waste aluminum electrolyte and calcined dolomite, comprising: mixing and grinding the waste aluminum electrolyte and calcined dolomite to obtain a second mixed material; wherein the end point particle size of the grinding is ≤150 μm; pre-pressing the second mixed material to obtain a mixed pre-material of waste aluminum electrolyte and calcined dolomite; wherein the pre-pressing pressure is 20 MPa; and the weight ratio of the waste aluminum electrolyte to the calcined dolomite is 1:6;

[0079] At a set temperature, the mixed preparation of waste aluminum electrolyte and dolomite calcined white is calcined to obtain a calcined material; wherein the set temperature is 1100° C. and the calcination time is 90 minutes;

[0080] The calcined material is mixed with an aluminum silicon reducing agent to obtain a first mixture; wherein the weight ratio of the calcined material to the aluminum silicon reducing agent is 1:0.28, the aluminum silicon reducing agent is a mixture of aluminum powder and silicon powder, and the weight ratio of aluminum to silicon in the mixture of aluminum powder and silicon powder is 20:1.

[0081] The first mixed material is pressed to obtain pellets to be processed; wherein the pressing pressure is 150 MPa;

[0082] subjecting the pellets to be treated to vacuum reduction to generate a mixed metal gas containing lithium, magnesium and sodium; and,

[0083] The mixed metal gas is crystallized in sections to obtain a magnesium-lithium alloy and metallic sodium; wherein the vacuum degree of the vacuum reduction is 4 Pa; the temperature of the vacuum reduction is 1100° C., and the time of the vacuum reduction is 50 minutes.

[0084] Example 3

[0085] A method for resource utilization of waste aluminum electrolyte, comprising:

[0086] Obtaining a mixed pre-material of waste aluminum electrolyte and calcined dolomite, comprising: mixing and grinding the waste aluminum electrolyte and calcined dolomite to obtain a second mixed material; wherein the end point particle size of the grinding is ≤150 μm; pre-pressing the second mixed material to obtain a mixed pre-material of waste aluminum electrolyte and calcined dolomite; wherein the pre-pressing pressure is 20 MPa; and the weight ratio of the waste aluminum electrolyte to the calcined dolomite is 1:8;

[0087] At a set temperature, the mixed preparation of waste aluminum electrolyte and dolomite calcined white is calcined to obtain a calcined material; wherein the set temperature is 1200°C and the calcination time is 30 minutes;

[0088] The calcined material is mixed with an aluminum silicon reducing agent to obtain a first mixture; wherein the weight ratio of the calcined material to the aluminum silicon reducing agent is 1:0.28, the aluminum silicon reducing agent is a mixture of aluminum powder and silicon powder, and the weight ratio of aluminum to silicon in the mixture of aluminum powder and silicon powder is 20:1.

[0089] The first mixed material is pressed to obtain pellets to be processed; wherein the pressing pressure is 150 MPa;

[0090] subjecting the pellets to be treated to vacuum reduction to generate a mixed metal gas containing lithium, magnesium and sodium; and,

[0091] The mixed metal gas is crystallized in sections to obtain a magnesium-lithium alloy and metallic sodium; wherein the vacuum degree of the vacuum reduction is 5 Pa; the temperature of the vacuum reduction is 1100° C., and the time of the vacuum reduction is 50 min.

[0092] Example 4

[0093] A method for resource utilization of waste aluminum electrolyte, comprising:

[0094] Obtaining a mixed pre-material of waste aluminum electrolyte and calcined dolomite, comprising: mixing and grinding the waste aluminum electrolyte and calcined dolomite to obtain a second mixed material; wherein the end point particle size of the grinding is ≤150 μm; pre-pressing the second mixed material to obtain a mixed pre-material of waste aluminum electrolyte and calcined dolomite; wherein the pre-pressing pressure is 20 MPa; and the weight ratio of the waste aluminum electrolyte to the calcined dolomite is 1:8;

[0095] At a set temperature, the mixed preparation of waste aluminum electrolyte and dolomite calcined white is calcined to obtain a calcined material; wherein the set temperature is 1000°C and the calcination time is 30 minutes;

[0096] The calcined material is mixed with an aluminum silicon reducing agent to obtain a first mixture; wherein the weight ratio of the calcined material to the aluminum silicon reducing agent is 1:0.2, the aluminum silicon reducing agent is a mixture of aluminum powder and silicon powder, and the weight ratio of aluminum to silicon in the mixture of aluminum powder and silicon powder is 50:1.

[0097] The first mixed material is pressed to obtain pellets to be processed; wherein the pressing pressure is 150 MPa;

[0098] subjecting the pellets to be treated to vacuum reduction to generate a mixed metal gas containing lithium, magnesium and sodium; and,

[0099] The mixed metal gas is crystallized in sections to obtain a magnesium-lithium alloy and metallic sodium; wherein the vacuum degree of the vacuum reduction is 3 Pa; the temperature of the vacuum reduction is 1100° C., and the time of the vacuum reduction is 50 minutes.

[0100] Comparative Example 1

[0101] Based on the disclosure of Example 1, the difference between Comparative Example 1 and Example 1 is that there is no calcination process, and the mixed preparation of waste aluminum electrolyte and dolomite calcined white is directly mixed with the aluminum silicon reducing agent.

[0102] Comparative Example 2

[0103] Based on the disclosure of Example 1, Comparative Example 2 differs from Example 1 in that an aluminum reducing agent is used instead of an aluminum silicon reducing agent.

[0104] The results of the valuable metal recovery rates of Examples 1 to 4 and Comparative Examples 1 to 3 are shown in Table 1 below:

[0105] Table 1 Valuable metal recovery results of Examples 1 to 4 and Comparative Examples 1 to 3

[0106] Serial number Lithium recovery rate (%) Magnesium recovery rate (%) Sodium recovery rate (%) Example 1 97.2 94.8 90.1 Example 2 93.1 93.2 92.8 Example 3 94.5 91.8 93.7 Example 4 93.4 90.5 87.8 Comparative Example 1 35.6 88.6 25.8 Comparative Example 2 82.1 90.8 89.0

[0107] As can be seen from Table 1, the method for resource utilization of waste aluminum electrolyte provided in the embodiment of the present application realizes the maximum utilization of valuable metal resources in the waste aluminum electrolyte while refining magnesium, and the recovery rates of lithium, magnesium and sodium are high; while the processes of comparative examples 1 to 2 do not meet the requirements of the embodiment of the present application, and reduce the recovery rates of lithium, magnesium and sodium to a certain extent.

[0108] One or more technical solutions in the embodiments of the present application also have at least the following technical effects or advantages:

[0109] (1) The embodiment of the present application proposes a technical idea of ​​synergistically extracting valuable metals from waste aluminum electrolyte and calcined dolomite, which realizes the maximum utilization of valuable metal resources in waste aluminum electrolyte while refining magnesium;

[0110] (2) The embodiments of the present application avoid the complexity of the current process of extracting lithium from waste aluminum electrolyte using various leaching methods;

[0111] (3) The embodiment of the present application regulates the ratio of aluminum to silicon in the reducing agent to form more stable 12CaO·7Al2O3 and 3CaO·Al2O3·3SiO2, and can also lower the reduction reaction temperature and improve the recovery rate of valuable metals;

[0112] (4) In the embodiment of the present application, waste aluminum electrolyte is mixed with dolomite calcined and calcined to convert the difficult-to-extract valuable metals in the waste into easily extractable ones while fixing fluorine.

[0113] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied for herein.

Claims

1. A method for resource utilization of waste aluminum electrolyte, the method comprising: Obtaining a mixed preparation of waste aluminum electrolyte and calcined dolomite; Calcining the mixed prepared material of the waste aluminum electrolyte and dolomite calcined white at a set temperature to obtain a calcined material; Mixing the calcined material with an aluminum-silicon reducing agent to obtain a first mixed material; Pressing the first mixed material to obtain pellets to be processed; The pellets to be treated are subjected to vacuum reduction to generate a mixed metal gas containing lithium, magnesium and sodium; and The mixed metal gas is subjected to segmented crystallization to obtain a magnesium-lithium alloy and metallic sodium.

2. The method according to claim 1, characterized in that The set temperature is 1000°C to 1200°C.

3. The method according to claim 1 or 2, characterized in that: The calcination time is 30 min to 120 min.

4. The method according to claim 1, characterized in that: The weight ratio of the waste aluminum electrolyte to the dolomite white is 1:(4-8).

5. The method according to claim 1, characterized in that The weight ratio of the calcined material to the aluminum silicon reducing agent is 1:(0.2-0.3).

6. The method according to claim 1, characterized in that The pressing pressure is 100Mpa to 200Mpa.

7. The method according to claim 1, characterized in that The process parameters of the vacuum reduction include: vacuum degree ≤5Pa, temperature 1000°C-1150°C.

8. The method according to claim 1, characterized in that The weight ratio of aluminum to silicon in the aluminum-silicon reducing agent is (9-50):

1.

9. The method according to claim 1, characterized in that: The mixed preparation of waste aluminum electrolyte and dolomite calcined white comprises: Mixing and grinding the waste aluminum electrolyte and calcined dolomite to obtain a second mixed material; The second mixed material is pre-pressed to obtain a mixed pre-material of waste aluminum electrolyte and dolomite calcined white.

10. The method according to claim 9, characterized in that The pre-pressing pressure is 10Mpa to 20Mpa.

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