Method for preparing white light LED device from coal gasification slag
By extracting silicon dioxide and aluminum oxide from coal gasification slag and synthesizing strontium aluminosilicate red phosphor, the method addresses the waste and cost issues, producing a high-quality white light LED device with improved luminescence.
Patent Information
- Application Number
- CN202411254647.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-09
- Publication Date
- 2024-12-27
AI Technical Summary
The disposal of coal gasification slag is wasteful and environmentally harmful, and the raw materials for strontium aluminosilicate red phosphor and white light LED devices are expensive and complex to prepare.
A method to extract silicon dioxide and aluminum oxide from coal gasification slag using acid leaching and alkali dissolution, followed by high-temperature solid phase synthesis to produce strontium aluminosilicate red phosphor, which is then used to create a white light LED device with blue and green phosphors in a near-ultraviolet LED chip.
The method reduces the cost of raw materials and enhances the luminescence quality of the white light LED device, achieving a CRI of 86.4 and luminescence intensity of 80% that of pure reagents, effectively utilizing coal gasification slag.
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Figure CN119191308A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to an application of coal gasification slag and a method for comprehensive utilization, and in particular to an application of coal gasification slag and a method for preparing strontium aluminosilicate red phosphor and white light LED devices using the coal gasification slag. Background Art
[0002] Coal is one of the main energy sources of industry. With the development of coal chemical industry, coal gasification technology has been widely used, which is an effective way to achieve clean, efficient, green and low-carbon coal. In the process of coal gasification, coal reacts with a variety of gasifying agents under high temperature, normal pressure or high pressure conditions to convert into gas fuel and generate solid waste. With the continuous advancement and development of coal gasification technology, the amount of coal gasification slag generated is increasing. At present, there is a great lack of development and utilization of coal gasification slag in the world. Most of the coal gasification slag is simply piled up or landfilled. This practice not only wastes resources, but also causes serious pollution to the ecological environment and land, and even endangers human health. Therefore, it is urgent to solve the problem of coal gasification slag treatment. In addition, the raw materials for the preparation of strontium aluminosilicate red phosphor and white light LED devices are currently expensive, the preparation method is complicated, and the cost is high; and the new application of coal gasification slag and the method for preparing white light LED using coal gasification slag as raw material have not yet been disclosed. Summary of the invention
[0003] In order to solve the above technical problems, the present invention provides a new use of coal gasification slag for preparing strontium aluminosilicate red phosphor and white light LED devices.
[0004] The present invention provides a method for preparing strontium aluminosilicate red phosphor from coal gasification slag, comprising the following steps:
[0005] 1) Weigh a certain amount of coal gasification slag and mix it with Na2CO3 powder, place it in a muffle furnace, and calcine it at 900-1000°C to obtain activated coal gasification slag powder;
[0006] 2) taking the activated coal gasification slag powder and adding it into dilute hydrochloric acid for sufficient acid leaching, washing, filtering and drying to obtain aluminum-containing filtrate and filter cake;
[0007] 3) adding the aluminum-containing filter cake obtained in step 2) into a NaOH solution, placing the solution in a water bath, and performing a water bath treatment; filtering the solution while hot to obtain an alkaline filtrate;
[0008] 4) titrating the alkaline filtrate obtained in step 3) with a hydrochloric acid solution to adjust the pH to 7.5 to obtain a Na2O·nSiO2 solution, which is then washed, filtered, dried, and ground to obtain silicon dioxide powder;
[0009] 5) titrating the aluminum-containing filtrate obtained in step 2) with a NaOH solution, adjusting the pH to be neutral, washing, filtering, and drying to obtain a filter cake containing Al and Fe elements;
[0010] 6) pouring the filter cake obtained in step 5) into a NaOH solution for alkaline dissolution, and filtering to obtain a mixed solution containing Fe(OH)3 and Al(OH)3 solutions;
[0011] 7) titrating the mixed solution obtained in step 6) with a hydrochloric acid solution, adjusting the pH to 9, washing, filtering, drying, calcining at 1000-1200° C., and grinding to obtain alumina powder;
[0012] 8) The silicon dioxide powder obtained in step 4), the aluminum oxide powder obtained in step 7), the strontium carbonate powder and the samarium oxide powder are weighed, mixed and ground according to a certain stoichiometric ratio, poured into a crucible and placed in a muffle furnace, calcined at 1200-1300° C., and ground after cooling to room temperature to obtain strontium aluminosilicate red phosphor; wherein the mass ratio of silicon dioxide powder to aluminum oxide powder is 1:2, the addition amount of strontium carbonate powder is 0.3-0.5wt%; and the samarium ion doping amount is 0.004-0.008mol%.
[0013] Preferably, in step 1), the mass ratio of coal gasification slag to Na2CO3 powder is preferably 25:13, the calcination temperature is preferably 920°C, and the temperature is maintained for 6 hours.
[0014] Preferably, in step 2), the concentration of dilute hydrochloric acid is preferably 0.05 mol / L, the solid-liquid ratio of the coal gasification slag powder to the dilute hydrochloric acid is 1:1, in g / ml; and the drying temperature is 120°C.
[0015] Preferably, in step 3), the concentration of the NaOH solution is preferably 6 wt %; the solid-liquid ratio of the aluminum-containing filter cake to the NaOH solution is 0.25; the water bath temperature is 90° C., and this temperature is maintained for 6 hours.
[0016] Preferably, in step 4), the concentration of hydrochloric acid is preferably 0.05 mol / L; and the drying temperature is 110°C.
[0017] Preferably, in step 5), the concentration of the NaOH solution is preferably 6 wt %; and the drying temperature is 100°C.
[0018] Preferably, in step 6), the concentration of the NaOH solution is preferably 6 wt %.
[0019] Preferably, in step 7), the concentration of hydrochloric acid is preferably 0.05 mol / L; the drying temperature is 110° C.; the calcination temperature is preferably 1100° C., and this temperature is maintained for 6 hours.
[0020] Preferably, in step 8), the calcination temperature is preferably 1250° C. and maintained at this temperature for 3 hours; the samarium ion doping amount is preferably 0.006 mol %.
[0021] The present invention also provides a method for preparing a white light LED device from coal gasification slag, the steps comprising:
[0022] The strontium aluminosilicate red phosphor prepared by the above method was mixed with the blue BaMgAl10O17:Eu 2+ and green (Sr,Ba)2SiO4:Eu 2+ The phosphors are mixed in a mass ratio of 1:3:6, placed in a near-ultraviolet LED chip, and sealed with glue to obtain a white light LED device.
[0023] The wavelength of the near-ultraviolet LED chip is 395nm.
[0024] Principles and beneficial effects of the present invention:
[0025] The invention adopts an acid leaching and alkali dissolution method to extract silicon dioxide and aluminum oxide raw materials from coal gasification slag, and adopts a high-temperature solid phase method to prepare strontium aluminosilicate phosphor from the raw materials, and finally prepares a white light LED device by glue sealing, and studies the white light LED device by means of testing such as X-ray diffraction XRD, scanning electron microscope SEM, ultraviolet spectrum UV-vis, fluorescence spectrum, fluorescence lifetime, electroluminescence, etc., and obtains the best process parameters, respectively, using purified raw materials, mixing silicon dioxide and aluminum oxide with strontium carbonate and samarium oxide, calcining at 1250°C, and the rare earth samarium ion doping amount is 0.006 mol%, and the luminescence intensity of the synthesized strontium aluminosilicate phosphor reaches 80% of the phosphor prepared by pure reagents; the CRI of the prepared white light LED device when the variable current is 300 mA is as high as 86.4, and the obtained white light LED device has the best luminescence quality. Compared with the white light LED device prepared by pure reagents, the synthesized device has excellent luminescence ability and can effectively replace the pure reagent raw materials.
[0026] The coal gasification slag of the present invention can be used to prepare white light LED devices, and strontium aluminosilicate phosphor powder is prepared from the coal gasification slag as a red raw material for white light LED devices. The raw material, coal gasification slag, is widely available and low in cost. Therefore, the cost of preparing strontium aluminosilicate red phosphor powder and white light LED devices is greatly reduced, which is of great significance to the comprehensive utilization and development of coal gasification slag. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 This is a schematic diagram of the raw material extraction process for preparing white light LEDs from coal gasification slag in the present invention.
[0028] Figure 2 This is a schematic flow chart of the method for preparing white light LED from coal gasification slag according to the present invention.
[0029] Figure 3 This is a physical picture of silicon dioxide extracted from coal gasification slag according to the present invention.
[0030] Figure 4 The figure is the XRD diagram of silicon dioxide extracted from coal gasification slag in the present invention.
[0031] Figure 5 This is a physical picture of the aluminum oxide extracted from coal gasification slag according to the present invention.
[0032] Figure 6 The figure is the XRD diagram of the alumina extracted from the coal gasification slag according to the present invention.
[0033] Figure 7 This is the XRD pattern of strontium aluminosilicate phosphor prepared after removing iron from the raw materials.
[0034] Figure 8 This is the XRD pattern of strontium aluminosilicate phosphor prepared without purification of raw materials.
[0035] Fig. 9 This is the XRD pattern of strontium aluminosilicate phosphor prepared after removing carbon from the raw materials.
[0036] Fig.10 XRD pattern of strontium aluminosilicate phosphor prepared from pure raw materials.
[0037] Fig.11 This is the XRD diagram of strontium aluminosilicate phosphor when the calcination temperature of the purified raw material is 1150°C.
[0038] Fig.12 This is the XRD diagram of strontium aluminosilicate phosphor when the calcination temperature of the purified raw material is 1200℃.
[0039] Fig.13 This is the XRD diagram of strontium aluminosilicate phosphor when the calcination temperature of the purified raw material is 1250°C.
[0040] Fig.14 This is the XRD diagram of strontium aluminosilicate phosphor when the calcination temperature of the purified raw material is 1300°C.
[0041] Fig.15 This is the XRD diagram of strontium aluminosilicate phosphor when the calcination temperature of the purified raw material is 1350°C.
[0042] Fig.16 This is the XRD pattern when doped with 0.002 mol% samarium ions.
[0043] Fig.17 This is the XRD pattern when doped with 0.004 mol% samarium ions.
[0044] Fig.18This is the XRD pattern when doped with 0.006 mol% samarium ions.
[0045] Fig.19 This is the XRD pattern when doped with 0.008 mol% samarium ions.
[0046] Fig. 20 This is the XRD pattern when doped with 0.01 mol% samarium ions.
[0047] Fig.21 This is the XRD pattern when doped with 0.02 mol% samarium ions.
[0048] Fig. 22 This is the XRD pattern when doped with 0.04 mol% samarium ions.
[0049] Fig.23 It is the electroluminescent spectrum of white light LED when the current is 20mA.
[0050] Fig.24 It is the electroluminescent spectrum of white light LED when the current is 40mA.
[0051] Fig.25 It is the electroluminescent spectrum of white light LED when the current is 50mA.
[0052] Fig.26 It is the electroluminescent spectrum of white light LED when the current is 100mA.
[0053] Fig. 27 It is the electroluminescent spectrum of white light LED when the current is 150mA.
[0054] Fig.28 It is the electroluminescent spectrum of white light LED when the current is 200mA.
[0055] Fig.29 It is the electroluminescent spectrum of white light LED when the current is 250mA.
[0056] Fig.30 It is the electroluminescent spectrum of white light LED when the current is 300mA. DETAILED DESCRIPTION
[0057] Embodiment 1,
[0058] See also Figure 1 As shown, the present embodiment provides a method for preparing strontium aluminosilicate red phosphor from coal gasification slag, comprising the following steps:
[0059] Preparation of activated coal gasification slag:
[0060] 1) Weigh 50g of coal gasification slag and 26g of Na2CO3 powder into a mortar and mix thoroughly. Put the mixture into a crucible and place it in a muffle furnace. Calcined at 920°C for 6 hours to obtain activated coal gasification slag powder. Repeat this step several times and collect the activated coal gasification slag powder.
[0061] Extraction of Silica:
[0062] 2) Pour 100 g of activated coal gasification slag powder into a beaker containing 100 mL of dilute hydrochloric acid, perform acid leaching, wash, filter and dry to obtain aluminum-containing filtrate and filter cake; the concentration of hydrochloric acid is 0.05 mol / L, and the drying temperature is 120°C;
[0063] 3) Pour the aluminum-containing filter cake obtained in step 2) into a beaker containing 300 mL of NaOH solution, place it in a water bath, and heat it in a water bath at 90° C. for 6 hours; the concentration of the NaOH solution is 6 wt %; after the water bath, filter the solution while hot to obtain an alkaline filtrate;
[0064] 4) The alkaline filtrate obtained in step 3) is titrated with 0.05 mol / L hydrochloric acid solution to adjust the pH to 7.5 to obtain a Na2O·nSiO2 solution, which is washed, filtered, dried and ground to obtain silicon dioxide powder; the drying temperature is 110°C.
[0065] like Figure 3 The actual picture of silicon dioxide extracted from coal gasification slag is shown in Figure 1. Figure 4 Shown is the XRD pattern of silicon dioxide extracted from coal gasification slag.
[0066] Extraction of Alumina:
[0067] 5) titrating the aluminum-containing filtrate obtained in step 2) with a 6 wt % NaOH solution, adjusting the pH to be neutral, washing, filtering and drying to obtain a filter cake containing Al and Fe elements; the drying temperature is 100° C.;
[0068] 6) Pour the filter cake obtained in step 5) into a beaker containing 400 mL of NaOH solution for alkaline dissolution, and filter to obtain a mixed solution containing Fe(OH)3 and Al(OH)3 solution; the concentration of the NaOH solution is 6 wt%;
[0069] 7) The mixed solution obtained in step 6) is titrated with 0.05 mol / L hydrochloric acid solution, and the pH is adjusted to 9, and then washed, filtered, dried, calcined at 1100° C. for 6 h, and ground to obtain alumina powder; the drying temperature is 110° C.
[0070] like Figure 5 The actual picture of alumina extracted from coal gasification slag is shown in Figure 6Shown is the XRD pattern of alumina extracted from coal gasification slag.
[0071] Preparation of strontium aluminosilicate phosphor:
[0072] 8) The silicon dioxide powder obtained in step 4), the aluminum oxide powder obtained in step 7), the strontium carbonate powder and the samarium oxide powder are weighed, mixed and ground according to a certain stoichiometric ratio, poured into a crucible and placed in a muffle furnace, calcined at 1250° C. for 3 hours, and then ground after cooling to room temperature to obtain strontium aluminosilicate red phosphor; wherein the mass ratio of silicon dioxide powder to aluminum oxide powder is 1:2, the amount of strontium carbonate powder added is 0.3wt%; and the amount of samarium ion doping is 0.006mol%.
[0073] like Figure 7 , which is the XRD pattern of the strontium aluminosilicate phosphor prepared in this example.
[0074] Embodiment 2,
[0075] See also Figure 2 As shown, the present embodiment provides a method for preparing a white light LED device from coal gasification slag, comprising the following steps:
[0076] The strontium aluminosilicate red phosphor prepared in Example 1 with a rare earth samarium doping amount of 0.006 mol% was mixed with a commercial blue BaMgAl10O17:Eu 2+ and green (Sr,Ba)2SiO4:Eu 2+ The phosphors are mixed and placed in a near-ultraviolet LED chip with a wavelength of 395nm, the current is changed to 300mA, and the white light LED device is obtained by sealing with glue.
[0077] According to analysis, the luminescence intensity of the synthesized strontium aluminosilicate phosphor reaches 80% of that of the phosphor prepared by pure reagents, and the CRI of the prepared white light LED device is as high as 86.4. Compared with the white light LED device prepared by pure reagents, the synthesized device has excellent luminescence ability and can effectively replace pure reagent raw materials.
[0078] Comparative Example 1
[0079] This comparative example generally adopts the method for preparing strontium aluminosilicate red phosphor from coal gasification slag provided in Example 1, but does not go through the activation process of step 1), and directly starts preparing strontium aluminosilicate red phosphor from step 2). Figure 8 Shown is the XRD pattern of the strontium aluminosilicate phosphor prepared from the raw materials of Comparative Example 1 without purification.
[0080] Comparative Example 2
[0081] This comparative example generally adopts the method for preparing strontium aluminosilicate red phosphor from coal gasification slag provided in Example 1, but without the iron removal steps of steps 6 and 7, the filter cake containing Al and Fe elements obtained in step 5 is directly calcined at 1100°C for 6 hours and then ground to obtain alumina powder; and then the strontium aluminosilicate red phosphor is prepared through step 8. Fig. 9 Shown is the XRD diagram of the strontium aluminosilicate phosphor prepared after carbon removal from the raw materials in Comparative Example 2.
[0082] Comparative Example 3
[0083] like Fig.10 Shown is the XRD pattern of strontium aluminosilicate phosphor prepared from pure raw materials after purification of coal gasification slag.
[0084] Embodiment 3,
[0085] This embodiment generally adopts the method for preparing strontium aluminosilicate red phosphor from coal gasification slag provided in Embodiment 1, and step 8 is to calcine at 1150, 1200, 1250, 1300, and 1350° C. for 3 hours respectively to prepare strontium aluminosilicate red phosphor.
[0086] like Figure 11-15 As shown, the XRD patterns of strontium aluminosilicate phosphors prepared at different calcination temperatures. The strontium aluminosilicate red phosphor prepared at a calcination temperature of 1250°C has the best performance.
[0087] Embodiment 4,
[0088] This embodiment generally adopts the method for preparing strontium aluminosilicate red phosphor from coal gasification slag provided in Embodiment 1. The doping amounts of samarium ions in step 8 are 0.002, 0.004, 0.006, 0.006, 0.01, 0.02, and 0.04 mol%, respectively. The XRD patterns of the prepared strontium aluminosilicate red phosphors are shown in FIG. Figure 16-22 As shown in the figure, the strontium aluminosilicate red phosphor prepared with samarium ion doping amount of 0.006 mol% has the best performance.
[0089] Embodiment 5,
[0090] This embodiment generally adopts the method for preparing a white light LED device from coal gasification slag provided in Example 2 to prepare a white light LED device. The electroluminescent spectrum of the white light LED device when the current is 20, 40, 50, 100, 150, 200, 250, and 300 mA is as follows: Figure 23-30 As shown, the luminous quality and luminous efficiency of the white light LED device are best when the variable current is 300mA.
Claims
1. A method for preparing strontium aluminosilicate red phosphor from coal gasification slag, characterized in that: The following steps are involved: 1) Weigh a certain amount of coal gasification slag and mix it with Na2CO3 powder, place it in a muffle furnace, and calcine it at 900-1000°C to obtain activated coal gasification slag powder; 2) taking the activated coal gasification slag powder and adding it into dilute hydrochloric acid for sufficient acid leaching, washing, filtering and drying to obtain aluminum-containing filtrate and filter cake; 3) washing and drying the aluminum-containing filter cake obtained in step 2), adding it to a NaOH solution, placing it in a water bath, and performing a water bath treatment; The solution is filtered while hot to obtain an alkaline filtrate; 4) titrating the alkaline filtrate obtained in step 3) with a hydrochloric acid solution to adjust the pH to 7.5 to obtain a Na2O·nSiO2 solution, which is then washed, filtered, dried, and ground to obtain silicon dioxide powder; 5) titrating the aluminum-containing filtrate obtained in step 2) with a NaOH solution, adjusting the pH to be neutral, washing, filtering, and drying to obtain a filter cake containing Al and Fe elements; 6) pouring the filter cake obtained in step 5) into a NaOH solution for alkaline dissolution, and filtering to obtain a mixed solution containing Fe(OH)3 and Al(OH)3 solutions; 7) titrating the mixed solution obtained in step 6) with a hydrochloric acid solution, adjusting the pH to 9, washing, filtering, drying, calcining at 1000-1200° C., and grinding to obtain alumina powder; 8) The silicon dioxide powder obtained in step 4), the aluminum oxide powder obtained in step 7), the strontium carbonate powder and the samarium oxide powder are weighed, mixed and ground according to a certain stoichiometric ratio, poured into a crucible and placed in a muffle furnace, calcined at 1200-1300° C., and ground after cooling to room temperature to obtain strontium aluminosilicate red phosphor; wherein the mass ratio of silicon dioxide powder to aluminum oxide powder is 1:2, the addition amount of strontium carbonate powder is 0.3-0.5wt%; and the samarium ion doping amount is 0.004-0.008mol%.
2. The method for preparing strontium aluminosilicate red phosphor from coal gasification slag according to claim 1, characterized in that: In step 1), the mass ratio of coal gasification slag to Na2CO3 powder is 25:13, the calcination temperature is 920°C, and the temperature is maintained for 6 hours.
3. The method for preparing strontium aluminosilicate red phosphor from coal gasification slag according to claim 1, characterized in that: In step 2), the solid-liquid ratio of the coal gasification slag powder to the dilute hydrochloric acid is 1:1, in g / ml; the concentration of the dilute hydrochloric acid is 0.05 mol / L, and the drying temperature is 120°C.
4. The method for preparing strontium aluminosilicate red phosphor from coal gasification slag according to claim 1, characterized in that: In step 3), the concentration of the NaOH solution is preferably 6 wt %; the solid-liquid ratio of the aluminum-containing filter cake to the NaOH solution is 0.25; the water bath temperature is 90° C., and this temperature is maintained for 6 hours.
5. The method for preparing strontium aluminosilicate red phosphor from coal gasification slag according to claim 1, characterized in that: In step 4), the concentration of hydrochloric acid is preferably 0.05 mol / L; and the drying temperature is 110°C.
6. The method for preparing strontium aluminosilicate red phosphor from coal gasification slag according to claim 1, characterized in that: In step 5) and step 6), the concentration of the NaOH solution is preferably 6 wt %; in step 5), the drying temperature is 100°C.
7. The method for preparing strontium aluminosilicate red phosphor from coal gasification slag according to claim 1, characterized in that: In step 7), the concentration of hydrochloric acid is preferably 0.05 mol / L; the drying temperature is 110° C.; the calcination temperature is preferably 1100° C., and this temperature is maintained for 6 hours.
8. The method for preparing strontium aluminosilicate red phosphor from coal gasification slag according to claim 1, characterized in that: In step 8), the calcination temperature is preferably 1250° C. and maintained at this temperature for 3 hours; the samarium ion doping amount is preferably 0.006 mol %.
9. A method for preparing a white light LED device from coal gasification slag, characterized in that: include: The strontium aluminosilicate red phosphor prepared by the method described in any one of claims 1 to 8 is mixed with the blue BaMgAl10O17:Eu 2+ and green (Sr,Ba)2SiO4:Eu 2+ The phosphors are mixed in a mass ratio of 1:3:6, placed in a near-ultraviolet LED chip, and sealed with glue to obtain a white light LED device.
10. The method for preparing a white light LED device from coal gasification slag according to claim 9, characterized in that: The wavelength of the near-ultraviolet LED chip is 395nm.