Method for preparing K2NaAlF6 cryolite by utilizing aluminum profile polishing waste liquid
K2NaAlF6 ice crystal was prepared by reacting the polishing waste liquid of aluminum profile with sodium fluoride and potassium fluoride, which solved the problems of complex process and low yield of the existing preparation methods, and achieved resource utilization and efficient preparation.
Patent Information
- Application Number
- CN202411694940.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-25
- Publication Date
- 2025-02-28
AI Technical Summary
The existing K2NaAlF6 ice crystal preparation method has complex processes, high equipment requirements and low yield, making it difficult to achieve resource utilization and environmental protection goals.
The aluminum profile polishing waste liquid was used as the aluminum source, and the ratio of the amount of reactants was adjusted by adding sodium fluoride and potassium fluoride to react at room temperature. Then, it was subjected to suction filtration, washing and drying of deionized water, and K2NaAlF6 ice crystal was successfully prepared.
The resource utilization of aluminum profile polishing waste liquid is realized, the preparation process is simple and the cost is low, the aluminum ions removal effect is good, the preparation cost is saved, and there is good application prospect.
Smart Images
Figure CN119528190A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of cryolite synthesis, and in particular relates to a method for preparing K2NaAlF6 cryolite by utilizing aluminum profile polishing waste liquid. Background Art
[0002] K2NaAlF6 is a variant of cryolite, which has shown its unique uses in many fields. In particular, its red phosphor doped with manganese ions has outstanding performance in LED lighting, especially for warm white LED (WLED), because it can absorb in the blue light region of 460nm and emit bright red light of about 630nm. The high light purity and heat resistance of this material make it have great potential in wide color gamut display and high-efficiency LED lighting. K NaAlF also has excellent heat and moisture resistance, and can maintain stable optical properties in high temperature and high humidity environments, which makes it a candidate for certain industrial materials.
[0003] There are two main traditional methods for preparing K2NaAlF6: (1) Weigh KF, NaF and AlF3 in a certain ratio in an agate mortar, grind and mix them, place them in a covered graphite crucible, and burn them at about 650℃ for 5h under Ar gas protection. After natural cooling, a polycrystalline powder sample is obtained. (2) Prepare K2NaAlF6 by evaporating a dilute solution of KF, NaF and Al2(SO4)3. However, the above methods have problems such as complex preparation process, high equipment requirements and low yield. Therefore, finding a method for preparing KNaAlF cryolite with simple process and high yield has become an important research work in LED lighting.
[0004] Before using, aluminum profiles are often polished to improve their surface finish and corrosion resistance. Aluminum profile polishing acid includes phosphoric acid and a certain proportion of sulfuric acid. Because of its high viscosity, it can form a viscous liquid film on the surface of the workpiece, selectively dissolve the micro-protrusions on the surface of the workpiece, and form a bright and dense oxide film layer on the surface of the workpiece. It is currently the most widely used aluminum profile polishing liquid. After repeated use, the aluminum profile polishing liquid will gradually lose its polishing effect and cannot be used when the concentration reaches a certain value due to the accumulation of aluminum ions in it, and then become polishing waste liquid. Due to the large amount of polishing waste liquid and its strong corrosiveness, it is an environmental problem that the aluminum profile chemical polishing industry urgently needs to solve. For aluminum profile polishing waste liquid, the traditional treatment method is to use alkali (such as lime, sodium hydroxide) to neutralize and then discharge it, but this method not only consumes a lot of alkali, but also produces a large amount of phosphorus-containing sludge, which will have the risk of secondary environmental pollution, and the added value is low, resulting in a waste of resources. How to turn aluminum profile polishing waste liquid into treasure and recycle it has become an important research topic today. Summary of the invention
[0005] In view of the problems existing in the background technology, the purpose of the present invention is to provide a method for preparing K2NaAlF6 cryolite by utilizing aluminum profile polishing waste liquid.
[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions:
[0007] A method for preparing K2NaAlF6 cryolite by using aluminum profile polishing waste liquid comprises the following steps:
[0008] S1. Take the aluminum profile polishing waste liquid and detect the components and contents of the aluminum profile polishing waste liquid;
[0009] S2, add sodium fluoride and potassium fluoride to the aluminum profile polishing waste liquid, so that K in the aluminum profile polishing waste liquid system + 、Na + 、Al 3+ and F - The amount of substance ratio n(K + ):n(Na + ):n(Al 3+ ):n(F - )=2:1:1:4~6, and then stir and react at room temperature;
[0010] S3. After the reaction is completed, the reaction product is filtered, washed with deionized water, filtered again, and dried to obtain K2NaAlF6 cryolite.
[0011] Preferably, in step S2, the reaction time at room temperature is 40 to 60 minutes;
[0012] Preferably, the drying temperature is 130-160° C., and the drying time is 6-12 hours.
[0013] The present invention has the following beneficial effects:
[0014] (1) The present invention provides a method for preparing K2NaAlF6 cryolite by using aluminum profile polishing waste liquid. The aluminum profile polishing waste liquid is used as an aluminum source, and the aluminum profile polishing waste liquid is reacted with sodium fluoride and potassium fluoride to successfully prepare K2NaAlF6 cryolite, thereby realizing the transformation of aluminum profile polishing waste liquid into treasure and resource utilization. In the present invention, aluminum profile polishing waste liquid is used as an aluminum source, and in the preparation process of K2NaAlF6 cryolite, the original aluminum in the aluminum profile polishing waste liquid is effectively utilized, thereby greatly saving the preparation cost.
[0015] (2) The preparation method of the present invention has a simple process, low cost, and good aluminum removal effect on aluminum profile polishing waste liquid, and provides a new way for the simple preparation of K2NaAlF6 cryolite, and therefore has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0017] Figure 1 The XRD pattern of K2NaAlF6 cryolite prepared in Example 1;
[0018] Figure 2 This is the aluminum removal effect of aluminum profile polishing waste liquid and the F residual amount result diagram. DETAILED DESCRIPTION
[0019] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.
[0020] Example 1
[0021] A method for preparing K2NaAlF6 cryolite by using aluminum profile polishing waste liquid comprises the following steps:
[0022] S1. Take the aluminum profile polishing waste liquid, and detect the components and contents of the aluminum profile polishing waste liquid. The results are shown in Table 1 below;
[0023] Table 1. Content of each component in aluminum profile polishing waste liquid
[0024] Element <![CDATA[H3PO4]]> <![CDATA[H2SO4]]> Al(III) Fe Cu Zn Cr Pb As Content (mg / L) 365220 240410 25.53 14.12 1.6 2.45 0.7 0.5 0.25
[0025] S2. According to the test results, sodium fluoride and potassium fluoride are added to the aluminum profile polishing waste liquid to make the K + 、Na + 、Al 3+ and F - The amount of substance ratio is n(K + ):n(Na + ):n(Al 3+ ):n(F - )=2:1:1:6, and then stirred at room temperature for 50 min;
[0026] S3. After the reaction is completed, the reaction product is filtered, and then the precipitate obtained by filtration is washed three times with deionized water, filtered again, and the obtained precipitate is placed in a drying oven at 150° C. and dried for 8 hours to obtain K2NaAlF6 cryolite.
[0027] Example 2
[0028] The steps are the same as those in Example 1, except that: in this example, sodium fluoride and potassium fluoride are added to make K in the aluminum profile polishing waste liquid system + 、Na + 、Al 3+ and F - The amount of substance ratio is n(K + ):n(Na + ):n(Al 3+ ):n(F - )=2:1:1:5, and K2NaAlF6 cryolite is obtained.
[0029] Example 3
[0030] The steps are the same as those in Example 1, except that: in this example, sodium fluoride and potassium fluoride are added to make K in the aluminum profile polishing waste liquid system + 、Na + 、Al 3+ and F - The amount of substance ratio is n(K + ):n(Na + ):n(Al 3+ ):n(F - )=2:1:1:4, and K2NaAlF6 cryolite is obtained.
[0031] Example 4
[0032] A method for preparing K2NaAlF6 cryolite by using aluminum profile polishing waste liquid comprises the following steps:
[0033] S1, steps are the same as in Example 1;
[0034] S2. According to the test results, sodium fluoride and potassium fluoride are added to the aluminum profile polishing waste liquid to make the K + 、Na + 、Al 3+ and F - The amount of substance ratio is n(K + ):n(Na + ):n(Al 3+ ):n(F - )=2:1:1:6, and then stirred at room temperature for 60 min;
[0035] S3. After the reaction is completed, the reaction product is filtered, and then the precipitate obtained by filtration is washed three times with deionized water, filtered again, and the obtained precipitate is placed in a drying oven at 150° C. and dried for 8 hours to obtain K2NaAlF6 cryolite.
[0036] Comparative Example 1
[0037] The steps are the same as those in Example 1, except that: sodium fluoride and potassium fluoride are added in this comparative example to make K + 、Na + 、Al 3+ and F - The amount of substance ratio is n(K + ):n(Na + ):n(Al 3+ ):n(F - )=2:1:1:3, and K2NaAlF6 cryolite is obtained.
[0038] Comparative Example 2
[0039] The steps are the same as those in Example 1, except that: sodium fluoride and potassium fluoride are added in this comparative example to make K + 、Na + 、Al 3+ and F - The amount of substance ratio is n(K + ):n(Na + ):n(Al 3+ ):n(F - )=2:1:1:2, and K2NaAlF6 cryolite is obtained.
[0040] Comparative Example 3
[0041] The steps are the same as those in Example 1, except that: sodium fluoride and potassium fluoride are added in this comparative example to make K + 、Na + 、Al 3+ and F - The amount of substance ratio is n(K + ):n(Na + ):n(Al 3+ ):n(F - )=2:1:1:1, and K2NaAlF6 cryolite is obtained.
[0042] Comparative Example 4
[0043] The steps are the same as those in Example 1, except that: sodium fluoride and potassium fluoride are added in this comparative example to make K + 、Na + 、Al3+ and F - The amount of substance ratio is n(K + ):n(Na + ):n(Al 3+ ):n(F - )=2:1:1:7, and K2NaAlF6 cryolite is obtained.
[0044] The K2NaAlF6 cryolite obtained in Example 1 was characterized. Figure 1 .
[0045] Depend on Figure 1 The results show that the diffraction peak of K2NaAlF6 cryolite prepared in Example 1 of the present invention corresponds to the XRD standard card of K2NaAlF6, indicating that the present invention successfully prepares K2NaAlF6 cryolite.
[0046] The aluminum removal effect and F residue of the aluminum profile polishing waste liquid used to prepare K2NaAlF6 cryolite in Examples 1-3 and Comparative Examples 1-3 were tested. The results are shown in Tables 2 and Figure 2 .
[0047] Table 2. Aluminum removal results
[0048] <h2 style=";text-align:left;direction:ltr"><![CDATA[n(F <h2 style=";text-align:left;direction:ltr"> - <h2 style=";text-align:left;direction:ltr"> ):n(Al<h2 style=";text-align:left;direction:ltr"> 3+ <h2 style=";text-align:left;direction:ltr"> ):n(Na<h2 style=";text-align:left;direction:ltr"> + <h2 style=";text-align:left;direction:ltr"> ):n(K<h2 style=";text-align:left;direction:ltr"> + <h2 style=";text-align:left;direction:ltr"> )]]><h2 style=";text-align:left;direction:ltr"> 1:1:1:2 2:1:1:2 3:1:1:2 4:1:1:2 5:1:1:2 6:1:1:2 7:1:1:2 F Residue (g / L) 0.428 0.66 0.61 0.714 0.716 1.017 6.702 Al removal rate (%) 41.86 46.01 58.47 75.08 87.54 100 100
[0049] From Table 2 and Figure 2 The results show that the present invention has a good removal effect when using sodium fluoride and potassium fluoride as precipitants to remove aluminum ions in aluminum profile polishing waste liquid, and as n(F - ):n(Al 3+ ) increases, the change trend of aluminum removal rate first gradually increases and then remains unchanged. 3+ )=6, the aluminum removal effect is best, the aluminum ion removal rate can reach up to 100%, and the F residual in the aluminum profile polishing waste liquid after treatment is 1.017g / L; by continuing to add sodium fluoride and potassium fluoride, the aluminum removal rate remains basically unchanged, the precipitation reaction reaches equilibrium, and the excess fluoride ions no longer combine with aluminum ions to form precipitates but accumulate in the aluminum profile polishing waste liquid. The fluoride ion content in the aluminum profile polishing waste liquid increases sharply to nearly 6.702g / L.
[0050] The present invention is not limited to the above-mentioned specific implementation modes. Various changes made by ordinary technicians in this field based on the above-mentioned concepts without creative work are all within the protection scope of the present invention.
Claims
1. A method for preparing K2NaAlF6 cryolite using aluminum profile polishing waste liquid, characterized in that: The following steps are involved: S1. Take the aluminum profile polishing waste liquid and detect the components and contents of the aluminum profile polishing waste liquid; S2, add sodium fluoride and potassium fluoride to the aluminum profile polishing waste liquid, so that K in the aluminum profile polishing waste liquid system + 、Na + 、Al 3+ and F - The amount of substance ratio n(K + ):n(Na + ):n(Al 3+ ):n(F - )=2:1:1:4~6, and then stir and react at room temperature; S3. After the reaction is completed, the reaction product is filtered, washed with deionized water, filtered again, and dried to obtain K2NaAlF6 cryolite.
2. The method for preparing K2NaAlF6 cryolite by using aluminum profile polishing waste liquid according to claim 1, characterized in that: The reaction time at room temperature is 40 to 60 minutes.
3. The method for preparing K2NaAlF6 cryolite by using aluminum profile polishing waste liquid according to claim 2, characterized in that: The drying temperature is 130-160° C., and the drying time is 6-12 hours.