Desiliconization method for high-aluminum coal gangue

Abstract

The invention relates to the technical field of metallurgy, in particular to a high-aluminum coal gangue desiliconization method which comprises the following steps: crushing and grinding high-aluminum coal gangue to obtain pretreated high-aluminum coal gangue; roasting and cooling the pretreated high-aluminum coal gangue to obtain activated coal gangue; mixing a sodium hydroxide solution with the activated coal gangue for reaction to obtain desiliconized slurry; filtering the desiliconized slurry, wherein a liquid phase is a sodium silicate solution; and washing the solid phase with water, and drying to obtain the desiliconized fly ash. The coal gangue selected by the invention is high-aluminum coal gangue, the aluminum content of the raw ore is 35-38%, the aluminum-silicon ratio of the raw ore is 0.8-0.9, the aluminum-silicon ratio after roasting activation reaches 0.85-0.95, and the aluminum-silicon ratio after one-step desiliconization can reach 5-8. Compared with the existing desiliconization technology, the technology not only can greatly improve the aluminum-silicon specific speed, but also can replace bauxite to be used as a raw material for preparing aluminum oxide by a Bayer process, so that the production cost is greatly reduced, and the utilization rate of resources is improved.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to a method for desiliconizing high-aluminum coal gangue. Background Art

[0002] In the process of aluminum industry development, bauxite resources have been seriously wasted due to long-term large-scale mining and the phenomenon of mining rich and abandoning poor, mining easy and abandoning difficult, and my country's bauxite resources are facing a grim situation. At present, the development of low-grade bauxite and the utilization of high-aluminum coal gangue and fly ash are imminent.

[0003] At present, when high-aluminum coal gangue / fly ash is used to prepare alumina, the initial aluminum-silicon ratio is too low and cannot be directly used in alumina production. Pre-desiliconization treatment is required first. Traditional desiliconization technology is mostly a one-step conventional alkaline desiliconization process. The process usually includes steps such as coal gangue crushing and ball milling, activation roasting, dilute acid aluminum dissolution, and alkaline desiliconization. After desiliconization, the aluminum-silicon ratio is generally only between 2-4. It is costly to use this low aluminum-silicon ratio raw material to prepare alumina by the Bayer process; if alumina is prepared by sintering, it will produce many disadvantages such as large amounts of red mud and high energy consumption, which seriously restricts the efficiency and sustainable development of alumina production. New technical methods are urgently needed to break through these bottlenecks. Summary of the invention

[0004] Based on the problems existing in the background technology, the coal gangue selected in the present invention is high-aluminum coal gangue, the aluminum content of the original ore is 35-38%, the aluminum-silicon ratio of the original ore is 0.8-0.9, the aluminum-silicon ratio reaches 0.85-0.95 after roasting and activation, and the aluminum-silicon ratio can reach 5-8 after one-step desiliconization. Compared with the existing desiliconization technology, this technology can not only greatly improve the aluminum-silicon ratio, but also replace bauxite as a raw material for preparing alumina by the Bayer process, greatly reducing the production cost and improving the utilization rate of resources.

[0005] The present invention is implemented by the following technical solutions: A method for desiliconizing high-aluminum coal gangue comprises the following steps: S1. crushing and grinding high-aluminum coal gangue to obtain pretreated high-aluminum coal gangue; S2. The pretreated high-aluminum gangue is roasted and cooled to obtain activated gangue; S3. Mixing the sodium hydroxide solution with the activated coal gangue to obtain a desiliconized slurry; S4. Filtering the desiliconized slurry, the liquid phase is a sodium silicate solution; S5. Wash the solid phase with water and then dry it to obtain desiliconized fly ash.

[0006] Furthermore, in step S1, the aluminum content of the high-aluminum coal gangue is 35-38%, and the aluminum-silicon ratio is 0.8-0.9.

[0007] Furthermore, in step S2, the calcination temperature is 950-1100° C., and the calcination time is 0.5-6 h.

[0008] Furthermore, the aluminum-silicon ratio of the activated coal gangue in step S2 is 0.85-0.95.

[0009] Furthermore, the concentration of the sodium hydroxide solution in step S3 is 100-400 g / L, preferably 250-400 g / L.

[0010] Furthermore, in step S3, the sodium hydroxide solution and the activated coal gangue are mixed at a liquid-to-solid ratio of (10-80):1, preferably (20-60):1.

[0011] Furthermore, in step S3, the temperature of the mixed reaction is 50-90°C, and the reaction time is 1-6h; preferably, the mixed reaction is divided into two stages, the reaction temperature of the first stage is 70-90°C, and the reaction time is 1-3h; the reaction temperature of the second stage is 60-80°C, and the reaction time is 1-3h; further preferably, the reaction temperature of the first stage is 85°C, and the reaction time is 1h; the reaction temperature of the second stage is 70°C, and the reaction time is 1h.

[0012] Furthermore, in step S5, the solid phase is washed with water 2 to 5 times.

[0013] Furthermore, the pre-treated high-aluminum coal gangue in step S1 includes three particle size components: fine particle size, medium particle size and coarse particle size; Among them, the fine particle size is 20~45μm, accounting for 40-50wt%; The medium particle size is 46~74μm, accounting for 30-40wt%; The coarse particle size is 75~150μm, accounting for 15-25wt%.

[0014] Beneficial effects of the present invention: 1. The aluminum-silicon ratio of the raw ore is 0.8-0.9, which reaches 0.85-0.95 after roasting and activation, and can reach 5-8 after a one-step desiliconization, and can even reach above 7.6 under optimal conditions. Compared with the existing technology, it has a qualitative leap and greatly improves the quality of raw materials, so that it can replace bauxite in the Bayer process for preparing alumina, fundamentally solving the problem of raw material applicability.

[0015] 2. The desiliconization efficiency of the method of the present invention reaches more than 80%, and can reach up to 88.1%. While effectively removing the silicon element, it ensures the retention and enrichment of the aluminum element, reduces the waste of raw materials, improves resource utilization, and reduces subsequent processing costs and energy consumption. It is of great significance in terms of economy and environmental protection, far exceeding the existing technical level, and fully reflects the creative value of the solution.

[0016] 3. The pre-treated high-aluminum coal gangue in the present invention includes three particle size components, and the combination of different particle sizes can play a synergistic role in the entire desiliconization process. The fine particle size can quickly start the reaction at the initial stage of the reaction, and the medium particle size and coarse particle size continue to provide reaction sites and diffusion channels in the subsequent stage, ensuring that the reaction continues to proceed efficiently, thereby improving the desiliconization efficiency and aluminum-silicon ratio improvement effect of the entire process. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0018] The solid phase composition of the high-aluminum coal gangue used in the examples and comparative examples of the present invention is shown in Table 1.

[0019] Table 1 Raw material solid phase composition

[0020] Example 1 A method for desiliconizing high-aluminum coal gangue comprises the following steps: S1. crushing and grinding high-aluminum coal gangue to obtain pretreated high-aluminum coal gangue, wherein the particle size of the pretreated high-aluminum coal gangue is 46~74μm; S2. The pretreated high-aluminum coal gangue was calcined at 1050°C for 2h and cooled to obtain activated coal gangue; S3. A sodium hydroxide solution having a concentration of 150 g / L was mixed with activated coal gangue at a liquid-to-solid ratio of 70:1, the reaction temperature was 80°C, the reaction time was 3 h, and a desiliconized slurry was obtained; S4. Filtering the desiliconized slurry, the liquid phase is a sodium silicate solution; S5. The solid phase is washed with water 5 times, and then dried to obtain desiliconized fly ash.

[0021] Example 2 A method for desiliconizing high-aluminum coal gangue comprises the following steps: S1. crushing and grinding high-aluminum coal gangue to obtain pretreated high-aluminum coal gangue, wherein the particle size of the pretreated high-aluminum coal gangue is 46~74μm; S2. The pretreated high-aluminum coal gangue was calcined at 1050°C for 2h and cooled to obtain activated coal gangue; S3. A sodium hydroxide solution having a concentration of 150 g / L was mixed with activated coal gangue at a liquid-to-solid ratio of 65:1, the reaction temperature was 80°C, the reaction time was 3 h, and a desiliconized slurry was obtained; S4. Filtering the desiliconized slurry, the liquid phase is a sodium silicate solution; S5. The solid phase is washed with water 5 times, and then dried to obtain desiliconized fly ash.

[0022] Example 3 A method for desiliconizing high-aluminum coal gangue comprises the following steps: S1. crushing and grinding high-aluminum coal gangue to obtain pretreated high-aluminum coal gangue, wherein the particle size of the pretreated high-aluminum coal gangue is 46~74μm; S2. The pretreated high-aluminum coal gangue was calcined at 1050°C for 2h and cooled to obtain activated coal gangue; S3. A 200 g / L sodium hydroxide solution was mixed with activated coal gangue at a liquid-solid ratio of 15:1, the reaction temperature was 80°C, the reaction time was 3 h, and a desiliconized slurry was obtained; S4. Filtering the desiliconized slurry, the liquid phase is a sodium silicate solution; S5. The solid phase is washed with water 5 times, and then dried to obtain desiliconized fly ash.

[0023] Example 4 A method for desiliconizing high-aluminum coal gangue comprises the following steps: S1. crushing and grinding high-aluminum coal gangue to obtain pretreated high-aluminum coal gangue, wherein the particle size of the pretreated high-aluminum coal gangue is 46~74μm; S2. The pretreated high-aluminum coal gangue was calcined at 1050°C for 2h and cooled to obtain activated coal gangue; S3. A sodium hydroxide solution having a concentration of 180 g / L was mixed with activated coal gangue at a liquid-to-solid ratio of 30:1, the reaction temperature was 75° C., the reaction time was 4 h, and a desiliconized slurry was obtained; S4. Filtering the desiliconized slurry, the liquid phase is a sodium silicate solution; S5. The solid phase is washed with water 5 times, and then dried to obtain desiliconized fly ash.

[0024] Example 5 A method for desiliconizing high-aluminum coal gangue comprises the following steps: S1. crushing and grinding high-aluminum coal gangue to obtain pretreated high-aluminum coal gangue, wherein the particle size of the pretreated high-aluminum coal gangue is 46~74μm; S2. The pretreated high-aluminum coal gangue was calcined at 1050°C for 2h and cooled to obtain activated coal gangue; S3. A 300 g / L sodium hydroxide solution was mixed with activated coal gangue at a liquid-solid ratio of 40:1, the reaction temperature was 75°C, the reaction time was 4 hours, and a desiliconized slurry was obtained; S4. Filtering the desiliconized slurry, the liquid phase is a sodium silicate solution; S5. The solid phase is washed with water 5 times, and then dried to obtain desiliconized fly ash.

[0025] Example 6 A method for desiliconizing high-aluminum coal gangue comprises the following steps: S1. crushing and grinding high-aluminum coal gangue to obtain pretreated high-aluminum coal gangue, wherein the particle size of the pretreated high-aluminum coal gangue is 46~74μm; S2. The pretreated high-aluminum coal gangue was calcined at 1050°C for 2h and cooled to obtain activated coal gangue; S3. A 300 g / L sodium hydroxide solution was mixed with activated coal gangue at a liquid-solid ratio of 30:1, the reaction temperature was 75°C, the reaction time was 4 hours, and a desiliconized slurry was obtained; S4. Filtering the desiliconized slurry, the liquid phase is a sodium silicate solution; S5. The solid phase is washed with water 5 times, and then dried to obtain desiliconized fly ash.

[0026] Example 7 A method for desiliconizing high-aluminum coal gangue comprises the following steps: S1. The high-aluminum coal gangue is crushed and ground to obtain pretreated high-aluminum coal gangue. The pretreated high-aluminum coal gangue includes three particle size components: fine particle size, medium particle size and coarse particle size. Among them, the fine particle size is 20~45μm, accounting for 45wt%; the medium particle size is 46~74μm, accounting for 35wt%; the coarse particle size is 75~150μm, accounting for 20wt%; S2. The pretreated high-aluminum coal gangue was calcined at 1050°C for 2h and cooled to obtain activated coal gangue; S3. A sodium hydroxide solution having a concentration of 180 g / L was mixed with activated coal gangue at a liquid-to-solid ratio of 30:1, the reaction temperature was 75° C., the reaction time was 4 h, and a desiliconized slurry was obtained; S4. Filtering the desiliconized slurry, the liquid phase is a sodium silicate solution; S5. The solid phase is washed with water 5 times, and then dried to obtain desiliconized fly ash.

[0027] Example 8 A method for desiliconizing high-aluminum coal gangue comprises the following steps: S1. The high-aluminum coal gangue is crushed and ground to obtain pretreated high-aluminum coal gangue, which includes three particle size components: fine particle size, medium particle size and coarse particle size; among which, the fine particle size is 20~45μm, accounting for 40wt%; the medium particle size is 46~74μm, accounting for 35wt%; the coarse particle size is 75~150μm, accounting for 25wt%; S2. The pretreated high-aluminum coal gangue was calcined at 1050°C for 2h and cooled to obtain activated coal gangue; S3. A sodium hydroxide solution having a concentration of 180 g / L was mixed with activated coal gangue at a liquid-to-solid ratio of 30:1, the reaction temperature was 75° C., the reaction time was 4 h, and a desiliconized slurry was obtained; S4. Filtering the desiliconized slurry, the liquid phase is a sodium silicate solution; S5. The solid phase is washed with water 5 times, and then dried to obtain desiliconized fly ash.

[0028] Example 9 A method for desiliconizing high-aluminum coal gangue comprises the following steps: S1. crushing and grinding high-aluminum coal gangue to obtain pretreated high-aluminum coal gangue, wherein the particle size of the pretreated high-aluminum coal gangue is 46~74μm; S2. The pretreated high-aluminum coal gangue was calcined at 1050°C for 2h and cooled to obtain activated coal gangue; S3. A sodium hydroxide solution having a concentration of 180 g / L and activated coal gangue are mixed and reacted at a liquid-to-solid ratio of 30:1. The temperature of the first stage reaction is 90°C and the reaction time is 1 h; the temperature of the second stage reaction is 60°C and the reaction time is 1.5 h to obtain a desiliconized slurry; S4. Filtering the desiliconized slurry, the liquid phase is a sodium silicate solution; S5. The solid phase is washed with water 5 times, and then dried to obtain desiliconized fly ash.

[0029] Example 10 A method for desiliconizing high-aluminum coal gangue comprises the following steps: S1. crushing and grinding high-aluminum coal gangue to obtain pretreated high-aluminum coal gangue, wherein the particle size of the pretreated high-aluminum coal gangue is 46~74μm; S2. The pretreated high-aluminum coal gangue was calcined at 1050°C for 2h and cooled to obtain activated coal gangue; S3. A sodium hydroxide solution having a concentration of 180 g / L is mixed with activated coal gangue at a liquid-to-solid ratio of 30:1, the temperature of the first stage of the reaction is 85°C, and the reaction time is 1 h; the temperature of the second stage of the reaction is 70°C, and the reaction time is 1 h, to obtain a desiliconized slurry; S4. Filtering the desiliconized slurry, the liquid phase is a sodium silicate solution; S5. The solid phase is washed with water 5 times, and then dried to obtain desiliconized fly ash.

[0030] Embodiment 11 A method for desiliconizing high-aluminum coal gangue comprises the following steps: S1. The high-aluminum coal gangue is crushed and ground to obtain pretreated high-aluminum coal gangue. The pretreated high-aluminum coal gangue includes three particle size components: fine particle size, medium particle size and coarse particle size. Among them, the fine particle size is 20~45μm, accounting for 45wt%; the medium particle size is 46~74μm, accounting for 35wt%; the coarse particle size is 75~150μm, accounting for 20wt%; S2. The pretreated high-aluminum coal gangue was calcined at 1050°C for 2h and cooled to obtain activated coal gangue; S3. A 300 g / L sodium hydroxide solution and activated coal gangue are mixed and reacted at a liquid-solid ratio of 40:1. The temperature of the first stage reaction is 85°C and the reaction time is 1 h; the temperature of the second stage reaction is 70°C and the reaction time is 1 h to obtain a desiliconized slurry; S4. Filtering the desiliconized slurry, the liquid phase is a sodium silicate solution; S5. The solid phase is washed with water 5 times, and then dried to obtain desiliconized fly ash.

[0031] Example 12 A method for desiliconizing high-aluminum coal gangue comprises the following steps: S1. crushing and grinding high-aluminum coal gangue to obtain pretreated high-aluminum coal gangue, wherein the particle size of the pretreated high-aluminum coal gangue is 46~74μm; S2. The pretreated high-aluminum gangue was calcined at 1100°C for 1.5h and cooled to obtain activated gangue; S3. A sodium hydroxide solution having a concentration of 150 g / L was mixed with activated coal gangue at a liquid-to-solid ratio of 70:1, the reaction temperature was 80°C, the reaction time was 3 h, and a desiliconized slurry was obtained; S4. Filtering the desiliconized slurry, the liquid phase is a sodium silicate solution; S5. The solid phase is washed with water 5 times, and then dried to obtain desiliconized fly ash.

[0032] Embodiment 13 A method for desiliconizing high-aluminum coal gangue comprises the following steps: S1. crushing and grinding high-aluminum coal gangue to obtain pretreated high-aluminum coal gangue, wherein the particle size of the pretreated high-aluminum coal gangue is 46~74μm; S2. The pretreated high-aluminum coal gangue was calcined at 950°C for 4h and cooled to obtain activated coal gangue; S3. A sodium hydroxide solution having a concentration of 150 g / L was mixed with activated coal gangue at a liquid-to-solid ratio of 70:1, the reaction temperature was 80°C, the reaction time was 3 h, and a desiliconized slurry was obtained; S4. Filtering the desiliconized slurry, the liquid phase is a sodium silicate solution; S5. The solid phase is washed with water 5 times, and then dried to obtain desiliconized fly ash.

[0033] In an embodiment, the process of crushing high-aluminum coal gangue includes: Identify and analyze the original image of high-aluminum coal gangue, and determine the material parameters and hardness parameters of the high-aluminum coal gangue according to the analysis results; Determine the crushing load response parameters of the crusher for high-aluminum coal gangue based on the material parameters and hardness parameters, and determine the reference control speed of the crusher according to the crushing load response parameters; Determine a target operating mode of the crusher according to a reference control speed, and determine a material crushing particle size of the crusher under the target operating mode; According to the crushing particle size parameters of high-aluminum coal gangue, determine whether the crushed material meets the grinding requirements based on the crushing particle size parameters of high-aluminum coal gangue; If not, determine the optimal particle size parameters according to the grinding requirements, and determine the crushing process based on the optimal particle size parameters; Determine multiple single crushing links and repeated crushing links according to the crushing process, and determine the common material characteristics of the single crushing links and repeated crushing links; Determine the optimization parameters based on the common characteristics of the materials, and optimize the crushing process according to the optimization parameters; Determine the material shape and volume requirements according to the grinding requirements, and determine the screening calibration parameters based on the material shape and volume requirements; The probability of good crushing is defined based on the screening calibration parameters and the preset utilization rate of high-aluminum coal gangue, and the optimal feeding frequency and the optimal single feeding amount are determined based on the probability of good crushing; A feeding strategy is generated based on the optimal feeding frequency and the optimal single feeding amount, and the crusher is controlled to perform feeding crushing according to the feeding strategy.

[0034] The beneficial effects of the above technical solution are: it can maximize the crushing effect of high-aluminum coal gangue while meeting the grinding requirements to improve work efficiency and screening efficiency. Furthermore, by intelligently controlling the crusher to crush high-aluminum coal gangue, the stability and reliability of the crushing can be guaranteed, while maximizing the utilization of raw materials, avoiding material loss, and improving practicality and stability.

[0035] In this embodiment, before crushing and grinding the high-aluminum coal gangue, the process further includes: Determine the texture parameters of high-aluminum coal gangue and collect multi-frame high-definition images of high-aluminum coal gangue; Determine the area ratio of high-aluminum coal gangue in each frame of high-definition image based on texture parameters, and determine the impurity content of high-aluminum coal gangue according to the area ratio; Determine whether the impurity content exceeds the standard. If so, use the image recognition algorithm to identify and analyze the impurities in the high-definition image; Determine the impurity shape determination parameter, the impurity type determination parameter and the impurity color determination parameter according to the first analysis content; Creating access matrices for impurities of various types and shapes based on impurity shape determination parameters, impurity type determination parameters, and impurity color determination parameters; Determine the identification parameters of impurities of various types and shapes by accessing the matrix and the impurity mask map, and build an impurity identification model through a deep learning network based on the identification parameters; Obtain sample images of different impurities and annotate them, and train the impurity recognition model through the annotated sample images; The impurity classification and location analysis of the real-time image of high-aluminum coal gangue is performed through the trained impurity recognition model; According to the second analysis content, the high-aluminum coal gangue samples are cleaned of impurities.

[0036] The beneficial effects of the above technical solution are: effective and stable impurity identification and filtering work can be carried out on samples of high-aluminum coal gangue to ensure subsequent work stability, thereby improving the material accuracy and reliability of high-aluminum coal gangue.

[0037] Comparative Example 1 A method for desiliconizing high-aluminum coal gangue comprises the following steps: S1. crushing and grinding high-aluminum coal gangue to obtain pretreated high-aluminum coal gangue, wherein the particle size of the pretreated high-aluminum coal gangue is 46~74μm; S2. The pretreated high-aluminum coal gangue was calcined at 1050°C for 2h and cooled to obtain activated coal gangue; S3. A 60 g / L sodium hydroxide solution was mixed with activated coal gangue at a liquid-solid ratio of 2.5:1, the reaction temperature was 80°C, the reaction time was 0.5 h, and a desiliconized slurry was obtained; S4. Filtering the desiliconized slurry, the liquid phase is a sodium silicate solution; S5. The solid phase is washed with water 5 times, and then dried to obtain desiliconized fly ash.

[0038] Comparative Example 2 A method for desiliconizing high-aluminum coal gangue comprises the following steps: S1. crushing and grinding high-aluminum coal gangue to obtain pretreated high-aluminum coal gangue, wherein the particle size of the pretreated high-aluminum coal gangue is 46~74μm; S2. The pretreated high-aluminum coal gangue was calcined at 1050°C for 2h and cooled to obtain activated coal gangue; S3. A 60 g / L sodium hydroxide solution was mixed with activated coal gangue at a liquid-solid ratio of 5:1, the reaction temperature was 80°C, the reaction time was 3 h, and a desiliconized slurry was obtained; S4. Filtering the desiliconized slurry, the liquid phase is a sodium silicate solution; S5. The solid phase is washed with water 5 times, and then dried to obtain desiliconized fly ash.

[0039] Comparative Example 3 A method for desiliconizing high-aluminum coal gangue comprises the following steps: S1. crushing and grinding high-aluminum coal gangue to obtain pretreated high-aluminum coal gangue, wherein the particle size of the pretreated high-aluminum coal gangue is 46~74μm; S2. The pretreated high-aluminum coal gangue was calcined at 1050°C for 2h and cooled to obtain activated coal gangue; S3. A sodium hydroxide solution having a concentration of 100 g / L was mixed with activated coal gangue at a liquid-solid ratio of 5:1, the reaction temperature was 80°C, the reaction time was 4 h, and a desiliconized slurry was obtained; S4. Filtering the desiliconized slurry, the liquid phase is a sodium silicate solution; S5. The solid phase is washed with water 5 times, and then dried to obtain desiliconized fly ash.

[0040] Comparative Example 4 A method for desiliconizing high-aluminum coal gangue comprises the following steps: S1. crushing and grinding high-aluminum coal gangue to obtain pretreated high-aluminum coal gangue, wherein the particle size of the pretreated high-aluminum coal gangue is 46~74μm; S2. The pretreated high-aluminum coal gangue was calcined at 1050°C for 2h and cooled to obtain activated coal gangue; S3. A 60 g / L sodium hydroxide solution was mixed with activated coal gangue at a liquid-solid ratio of 30:1, the reaction temperature was 75°C, the reaction time was 4 hours, and a desiliconized slurry was obtained; S4. Filtering the desiliconized slurry, the liquid phase is a sodium silicate solution; S5. The solid phase is washed with water 5 times, and then dried to obtain desiliconized fly ash.

[0041] Test example The solid phase components of activated coal gangue were tested, and the specific results are shown in Table 2.

[0042] Table 2 Solid phase composition of activated coal gangue

[0043] The solid phase composition of the desiliconized fly ash finally obtained in Examples 1-8 and Comparative Examples 1-4 was tested, and the specific results are shown in Table 3.

[0044] Table 3 The solid phase composition of the desiliconized fly ash obtained in Examples 1-8 and Comparative Examples 1-4

[0045] It can be seen from the results in Table 3 that in the embodiments of the present application, after desiliconization by a large liquid-to-solid ratio, the aluminum content is 72-77%, the silicon content is 9-16%, the silicon-aluminum ratio can reach a maximum of more than 8.3, and the desiliconization efficiency is greater than 88%.

[0046] The components of the desiliconized slurry obtained in Examples 1-8 were analyzed, and the specific results are shown in Table 4.

[0047] Table 4 Composition of the desiliconized slurry obtained in Examples 1-11

[0048] Finally, it should be noted that the above-mentioned embodiments only express several implementation methods of the present invention and are not intended to limit the invention. For those skilled in the art, any modification, equivalent replacement, improvement, etc. made without departing from the concept of the present invention should be included in the protection scope of the invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for desiliconization of high-aluminum coal gangue, characterized in that: The following steps are involved: S1. crushing and grinding high-aluminum coal gangue to obtain pretreated high-aluminum coal gangue; S2. The pretreated high-aluminum gangue is roasted and cooled to obtain activated gangue; S3. Mixing the sodium hydroxide solution with the activated coal gangue to obtain a desiliconized slurry; S4. Filtering the desiliconized slurry, the liquid phase is a sodium silicate solution; S5. Wash the solid phase with water and then dry it to obtain desiliconized fly ash.

2. The high-aluminum coal gangue desiliconization method according to claim 1, characterized in that: In step S2, the calcination temperature is 950-1100° C., and the calcination time is 0.5-6 hours.

3. The high-aluminum coal gangue desiliconization method according to claim 1, characterized in that: The concentration of the sodium hydroxide solution in step S3 is 100-400 g / L.

4. The method for desiliconizing high-aluminum coal gangue according to claim 3, characterized in that: The concentration of the sodium hydroxide solution in step S3 is 250-400 g / L.

5. The high-aluminum coal gangue desiliconization method according to claim 1, characterized in that: In step S3, the sodium hydroxide solution and the activated coal gangue are mixed at a liquid-to-solid ratio of (10-80):

1.

6. The method for desiliconizing high-aluminum coal gangue according to claim 5, characterized in that: In step S3, the sodium hydroxide solution and the activated coal gangue are mixed at a liquid-to-solid ratio of (20-60):

1.

7. The method for desiliconizing high-aluminum coal gangue according to claim 1, characterized in that: The temperature of the mixed reaction in step S3 is 50-90° C., and the reaction time is 1-6 hours.

8. The method for desiliconizing high-aluminum coal gangue according to claim 7, characterized in that: The mixed reaction in step S3 is divided into two stages. The reaction temperature of the first stage is 70-90° C. and the reaction time is 1-3 h; the reaction temperature of the second stage is 60-80° C. and the reaction time is 1-3 h.

9. The method for desiliconizing high-aluminum coal gangue according to claim 8, characterized in that: The reaction temperature of the first stage was 85°C and the reaction time was 1 h; the reaction temperature of the second stage was 70°C and the reaction time was 1 h.

10. The method for desiliconizing high-aluminum coal gangue according to claim 1, characterized in that: The pre-treated high-aluminum coal gangue in step S1 includes three particle size components: fine particle size, medium particle size and coarse particle size; Among them, the fine particle size is 20~45μm, accounting for 40-50wt%; The medium particle size is 46~74μm, accounting for 30-40wt%; The coarse particle size is 75~150μm, accounting for 15-25wt%.

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