Method for preparing 4N8-grade high-purity quartz sand through external field enhanced acid leaching and cleaning equipment

Abstract

The invention discloses a method for preparing 4N8-grade high-purity quartz sand through external field enhanced acid leaching and cleaning equipment, and belongs to the technical field of high-purity quartz purification processes, the method comprises the following steps: S1, after a to-be-treated object is cleaned and dried, roasting and water quenching treatment are performed in sequence, and a first treated object is obtained; s2, mixing the first treated substance with the leachate, carrying out microwave external field enhanced high-temperature acid leaching treatment, and then cleaning a leached product to be neutral, so as to obtain a second treated substance; s3, the second treated matter is prepared into ore pulp, a collecting agent is added into the ore pulp for flotation treatment, after impurities are removed, concentrate obtained through flotation is cleaned to be neutral, and a third treated matter is obtained; s4, dehydrating and drying the third treated product, and performing magnetic separation and impurity removal under magnetic field intensity to obtain 4N8-grade high-purity quartz sand; the method for preparing the high-purity quartz sand is fluoride-free, nitrate-free, green and environment-friendly, and severe influence and pollution to human bodies and the environment caused by use of hydrofluoric acid are avoided.

Description

Technical Field

[0001] This invention relates to the field of high-purity quartz purification technology, specifically to a method and cleaning equipment for preparing 4N8 grade high-purity quartz sand by field-enhanced acid leaching. Background Technology

[0002] High-purity quartz sand has an SiO2 content of ≥99.998% and possesses excellent properties such as high temperature resistance, corrosion resistance, and high insulation. It is widely used in semiconductor, photovoltaic, new energy, and military industries. Only high-quality first-grade and second-grade crystals in nature can meet the requirements. However, due to the limited reserves of high-quality crystal resources in my country and the rapid development of global fiber optic communication and semiconductor industries, these resources are becoming increasingly depleted. Therefore, purifying high-purity quartz sand from quartz sand resources using various sorting and purification methods has become a current research focus.

[0003] High-purity quartz is mainly prepared from natural crystal, but my country has scarce crystal resources, so low-purity quartz is often used to replace the increasingly depleted crystal resources in the preparation of high-purity quartz sand. However, in recent years, traditional glass manufacturers have continued to expand their photovoltaic glass production capacity, and new companies have been entering the market. my country's photovoltaic glass production accounts for more than 90% of the global total, and the domestic photovoltaic glass industry shows obvious cyclical and structural overcapacity. The production capacity of photovoltaic glass sand is already excessive, so there is an urgent need to deeply purify the excess quartz sand.

[0004] Currently, the main technologies for quartz sand purification include magnetic separation, flotation, roasting, and acid leaching. Acid leaching is usually used as a deep purification process to remove some inclusions and impurities from quartz sand. In existing technologies, such as the acid leaching solutions used in publications CN120288779A, CN118637628A, and CN114956102A, hydrofluoric acid is generally present. However, hydrofluoric acid is highly volatile, and HF gas is harmful, irritating, and highly corrosive. Long-term exposure is carcinogenic and increases the risk of cancer, posing a great danger to operators. The fluorine in hydrofluoric acid also causes serious environmental pollution, which is inconsistent with the environmental protection concept advocated by today's society. In addition, research has found that relying solely on wet acid leaching to achieve deep removal of impurities from quartz sand faces greater challenges, and the SiO2 content is difficult to reach a higher level after ordinary acid leaching. Summary of the Invention

[0005] The purpose of this invention is to provide a method and cleaning equipment for preparing 4N8 grade high-purity quartz sand by field-enhanced acid leaching, which solves the problems existing in the current quartz sand purification technology.

[0006] This invention achieves the above objective through the following technical solution: a method for preparing 4N8 grade high-purity quartz sand by field-enhanced acid leaching, comprising the following steps: S1: After cleaning and drying the material to be processed, it is then subjected to roasting and water quenching treatments in sequence to obtain the first processed material; S2: Mix the first processed material with the leachate, perform microwave-enhanced high-temperature acid leaching treatment, and then wash the leachate until neutral to obtain the second processed material. S3: The second processed material is prepared into a slurry, and a collector is added to it for flotation treatment to remove impurities. The concentrate obtained from the flotation is washed until neutral to obtain the third processed material. S4: The third processed material is dehydrated, dried, and then subjected to magnetic separation under a magnetic field to remove impurities, resulting in 4N8 grade high-purity quartz sand.

[0007] Preferably, the material to be processed in step S1 is quartzite sand.

[0008] Preferably, in step S1, the material to be treated is calcined at 900-1100℃ for 10-40 minutes, and the water used for water quenching is ultrapure water.

[0009] Preferably, the leachate is a mixed solution of sulfuric acid and ammonium chloride, wherein the concentration of the sulfuric acid solution is 0.2-0.8 mol / L and the concentration of the ammonium chloride solution is 0.4-1.6 mol / L; The high-temperature acid leaching reaction temperature is 220-240℃, the reaction time is 10-12h, and the liquid-solid ratio of the first treated material to the leachate is 3:1-6:1.

[0010] Preferably, in step S3, the slurry concentration is 30-40%, the pH value is adjusted to 2-4, and the amount of the collector dodecylamine is 500-700 g / t, wherein the collector is dodecylamine.

[0011] Preferably, the magnetic field strength in step S4 is 0.9-1.7T.

[0012] Preferably, a cleaning device is used to clean the material to be treated in the above-mentioned field-enhanced acid leaching method for preparing N-grade high-purity quartz sand, comprising: a cleaning tank, wherein a screen is provided inside the cleaning tank, and cleaning pools are provided on both the upper and lower sides of the inner cavity of the cleaning tank; two rinsing mechanisms are provided inside the cleaning tank and respectively matched with the two cleaning pools; and a guide block is provided at the bottom of the inner cavity of the cleaning tank.

[0013] Preferably, a blocking element is provided at the top of the inner cavity of the cleaning tank; The blocking component includes a support plate, a movable plate, and an adjustment assembly for driving the movable plate to rise and fall.

[0014] Preferably, the cleaning tank includes a tank body, a mounting plate detachably connected to the tank body, a tilting component disposed on the mounting plate, a drive motor for driving the tilting component to rotate, and a scraper disposed on the tilting component. The bottom of the pool is provided with a drainage hole.

[0015] Preferably, the bottom of the pool is provided with a guide plate.

[0016] The beneficial effects of this invention are as follows: 1. The method for producing high-purity quartz sand is fluorine-free, nitrate-free, green, and environmentally friendly. Under microwave conditions, based on the different dielectric constants of substances in the microwave field, the impurity phase and the silica phase have different heating rates. The quartz sand is acid-leached by strengthening the microwave external field. The high-temperature heating promotes the penetration of the acid leaching solution, causing the impurity inclusions in the quartz sand to dissolve, thereby greatly improving the impurity removal rate. After deep purification, its added value can be greatly increased, effectively reducing resource waste. 2. The method for preparing 4N8 grade high-purity quartz sand by field-enhanced acid leaching of quartzite sand provided in this invention uses quartzite sand with low SiO2 content as raw material to prepare high-purity quartz sand with SiO2 content exceeding 99.998wt%, and the impurity element content in the high-purity quartz sand is low, which can meet the industry's demand for high-purity quartz sand. Moreover, the preparation process does not use fluorine-containing reagents, which is environmentally friendly, greatly improves its utilization added value, and effectively reduces the waste of quartz resources. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of the cleaning device of the present invention; Figure 2 For the present invention Figure 1 Enlarged schematic diagram of the structure at point A in the middle; Figure 3 This is a schematic diagram of the cleaning tank structure of the present invention.

[0018] In the diagram: 1. Cleaning tank; 2. Screen; 3. Flushing mechanism; 4. Cleaning pool; 401. Pool body; 402. Scraper; 403. Mounting plate; 404. Drive motor; 405. Tilting component; 5. Guide plate; 6. Blocking component; 601. Support plate; 602. Movable plate; 603. Adjustment component; 7. Guide block. Detailed Implementation

[0019] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0020] Example 1

[0021] A method for preparing 4N8 grade high-purity quartz sand by external field enhanced acid leaching includes the following steps: the raw material is quartzite quartz sand, which is roasted and water-quenched, and then subjected to microwave external field enhanced acid leaching combined with sulfuric acid / ammonium chloride, and after impurity removal, it can reach 4N8 grade; including the following steps: S1: First, the quartzite and quartz sand are cleaned and dried. After drying, the quartzite and quartz sand are calcined at 900-1100℃ for 10-40 minutes. After calcination, the quartzite and quartz sand are water-quenched to remove impurities. The water used for water quenching is ultrapure water, and the water tank is lined with polytetrafluoroethylene to prevent contamination. After water quenching, the quartzite and quartz sand are cleaned. S2: The calcined and water-quenched quartz sand is mixed with the leachate and subjected to microwave-enhanced high-temperature acid leaching. The high-temperature acid leaching reaction temperature is 220-240℃, and the acid leaching reaction time is 10-12h. The leachate is a mixed solution of sulfuric acid and ammonium chloride. The concentration of the sulfuric acid solution is 0.2-0.8mol / L, and the concentration of the ammonium chloride solution is 0.4-1.6mol / L. After the enhanced acid leaching is completed, the leaching product is washed until neutral. Microwave field enhancement is achieved by embedding a microwave generator in the pickling reactor. Microwave heating can significantly improve the acid leaching efficiency. The combined effect of sulfuric acid and ammonium chloride with microwaves can complex impurity ions and improve the impurity removal effect. The liquid-solid ratio of quartzite sand to leachate is 3:1-6:1, and the total volume of quartzite sand and leachate does not exceed two-thirds of the total volume of the reactor. The microwave power is 1800-2400W, and the microwave frequency is 400MHz-5500MHz. S3: The acid-leached quartz sand is prepared into a slurry with a concentration of 30-40% and a pH value of 2-4. Under the condition of a slurry temperature of 30-50℃, dodecylamine, a collector, is added to the slurry for flotation treatment to remove impurities. The dosage of dodecylamine is 500-700 g / t. After flotation treatment, the quartz sand flotation concentrate is washed until neutral. S4: The flotation-fled quartz sand is dehydrated and dried, and then magnetically separated under a magnetic field strength of 0.9-1.7T to remove impurities, thus obtaining 4N8 grade high-purity quartz sand.

[0022] It should be noted that the method for preparing high-purity quartz sand using quartzite sand as raw material through field-enhanced acid leaching provided in this application involves calcining and water quenching the quartzite sand. During the calcination process at 700-1100℃ for 10-40 minutes, the quartz particles, impurity mineral inclusions, and gas-liquid inclusions experience different expansion forces due to their different coefficients of thermal expansion. Simultaneously, the water quenching treatment causes the quartz particles to be subjected to various forces, including the contraction force due to cooling and the internal thermal expansion force, resulting in changes in the quartz particle surface, grain boundaries, gas-liquid inclusions, and mineral inclusions. Cracks are generated at the inclusions, exposing the impurity minerals within them. This process removes trace lattice impurities and gas-liquid inclusions that are difficult to remove, and the presence of numerous cracks increases the contact surface area for subsequent leaching. Then, high-temperature acid leaching is performed using microwave field enhancement combined with sulfuric acid / ammonium chloride to effectively reduce the impurity content in the quartz sand. Next, flotation is carried out under acidic conditions using dodecylamine as a collector to remove feldspar and mica-like impurity minerals with high impurity content. After dehydration and drying, magnetic separation is used to remove impurities, ultimately yielding 4N8 grade high-purity quartz sand.

[0023] Example 2

[0024] As a further optimization of Example 1, please refer to Figure 1 A cleaning device is used to clean quartzite and quartz sand in step S1 above. The cleaning device includes: a cleaning tank 1, with a feed inlet on the top wall of the cleaning tank 1; a screen 2 in the inner cavity of the cleaning tank 1, located in the middle of the inner cavity and inclined to the lower right; a guide block 7 at the bottom of the inner cavity of the cleaning tank 1 (the top wall of the guide block 7 is a slope, inclined to the right); cleaning pools 4 on both the upper and lower sides of the inner cavity of the cleaning tank 1, located on the top right side of the screen 2 and the guide block 7 respectively; and two rinsing mechanisms 3 in the inner cavity of the cleaning tank 1 (each rinsing mechanism 3 includes a pipe and a nozzle mounted on the pipe). (Connected to an external water storage tank and pump), two flushing mechanisms 3 are located above two cleaning tanks 4 respectively; quartzite sand is added into the cleaning tank 1 through the feed inlet, and after being filtered by the screen 2, the smaller quartzite sand falls above the guide block 7 and is guided by it into the lower cleaning tank 4, while the larger quartzite sand remaining on the screen 2 enters the upper cleaning tank 4. Water is flushed into the cleaning tank 4 by the flushing mechanism 3 to wash the quartzite sand; the quartzite sand is screened by the screen 2 so that the larger and smaller quartzite sand are washed and cleaned separately, ensuring that the quartzite sand is cleaned thoroughly.

[0025] In this embodiment, as a further optimization, please refer to... Figure 1 and Figure 2The inner cavity of the washing tank 1 is equipped with a blocking component 6 at the top. The blocking component 6 is located on the right side of the feed inlet and is vertically arranged to increase the time that the quartz sand falls onto the screen 2, ensuring that the screen 2 accurately sieves the quartz sand. The blocking component 6 includes a support plate 601, a movable plate 602, and an adjusting component 603. The movable plate 602 is slidably mounted on the side wall of the support plate 601. The adjusting component 603 includes a moving rod, a kit, and bolts. The kit is installed on the top wall of the washing tank 1. The moving rod is slidably inserted into the kit and connected to the movable plate 602. The bolts are screwed to the side wall of the kit and fix the moving rod. The moving rod slides within the kit to raise and lower the movable plate 602, changing the distance between the movable plate 602 and the screen 2, so that the speed at which the quartz sand passes through the blocking component 6 can be adjusted according to requirements.

[0026] In this embodiment, as a further optimization, please refer to... Figure 1 and Figure 3 The cleaning tank 4 includes a tank body 401, with an open area at the top and front. A mounting plate 403 is detachably mounted on the front wall of the tank body 401 (the mounting plate 403 is bolted to the tank body 401). A flipping component 405 (including a rotating shaft and a flap on the side wall of the rotating shaft, with the front end of the rotating shaft rotatably mounted on the rear wall of the mounting plate 403) is mounted on the front wall of the mounting plate 403. A drive motor 404 is mounted on the front wall of the mounting plate 403, with its output shaft connected to the rotating shaft. The drive motor 404 drives the flipping component 405 to rotate. A scraper 40 is mounted at the rear end of the rotating shaft. 2. The rotating shaft is rotatably connected to the scraper 402, which is located in the inner cavity of the pool body 401. The bottom of the pool body 401 is provided with a drain hole. When the water rinses the quartzite sand inside the cleaning pool 4, the drive motor 404 drives the rotating shaft to rotate with the scraper, turning the quartzite sand over and rinsing it clean. The water during the rinsing process is drained away through the drain hole. After rinsing, the connection between the mounting plate 403 and the pool body 401 is released, and the mounting plate 403 is moved forward, causing the rotating shaft to move forward with the scraper 402 to scrape out the quartzite sand inside the pool body 401, making it easier to remove the quartzite sand from the cleaning pool 4.

[0027] In this embodiment, as a further optimization, please refer to... Figure 1 The bottom of the pool body 401 is provided with a guide plate 5, which is used to guide the wastewater discharged from the inside of the pool body 401.

[0028] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for preparing 4N8 grade high-purity quartz sand by external field enhanced acid leaching, characterized in that, Includes the following steps: S1: After cleaning and drying the material to be processed, it is then subjected to roasting and water quenching treatments in sequence to obtain the first processed material; S2: Mix the first processed material with the leachate, perform microwave-enhanced high-temperature acid leaching treatment, and then wash the leachate until neutral to obtain the second processed material. S3: The second processed material is prepared into a slurry, and a collector is added to it for flotation treatment to remove impurities. The concentrate obtained from the flotation is washed until neutral to obtain the third processed material. S4: The third processed material is dehydrated, dried, and then subjected to magnetic separation under a magnetic field to remove impurities, resulting in 4N8 grade high-purity quartz sand.

2. The method for preparing 4N8 grade high-purity quartz sand by external field enhanced acid leaching according to claim 1, characterized in that, The material to be processed in step S1 is quartzite sand.

3. The method for preparing 4N8 grade high-purity quartz sand by external field enhanced acid leaching according to claim 1, characterized in that, In step S1, the material to be treated is calcined at 900-1100℃ for 10-40 minutes, and the water used for water quenching is ultrapure water.

4. The method for preparing 4N8 grade high-purity quartz sand by external field enhanced acid leaching according to claim 1, characterized in that, The leachate is a mixed solution of sulfuric acid and ammonium chloride, with the sulfuric acid solution having a concentration of 0.2-0.8 mol / L and the ammonium chloride solution having a concentration of 0.4-1.6 mol / L. The high-temperature acid leaching reaction temperature is 220-240℃, the reaction time is 10-12h, and the liquid-solid ratio of the first treated material to the leachate is 3:1-6:

1.

5. The method for preparing 4N8 grade high-purity quartz sand by external field enhanced acid leaching according to claim 1, characterized in that, In step S3, the pulp concentration is 30-40%, the pH value is adjusted to 2-4, and the amount of the collector dodecylamine is 500-700 g / t. The collector is dodecylamine.

6. The method for preparing 4N8 grade high-purity quartz sand by external field enhanced acid leaching according to claim 1, characterized in that, The magnetic field strength in step S4 is 0.9-1.7T.

7. A cleaning device for cleaning the material to be treated in the method for preparing 4N8 grade high-purity quartz sand by field-enhanced acid leaching as described in any one of claims 1-6, characterized in that, include: The cleaning box (1) is equipped with a screen (2), and the cleaning box (1) has cleaning pools (4) on both the upper and lower sides of the inner cavity. The cleaning box (1) is equipped with two rinsing mechanisms (3) that are respectively matched with the two cleaning pools (4). The bottom of the inner cavity of the cleaning box (1) is equipped with a guide block (7).

8. A cleaning device according to claim 7, characterized in that, The top of the inner cavity of the cleaning tank (1) is provided with a blocking element (6); The blocking member (6) includes a support plate (601), a movable plate (602), and an adjustment assembly (603) for driving the movable plate (602) to rise and fall.

9. A cleaning device according to claim 7, characterized in that, The cleaning tank (4) includes a tank body (401), a mounting plate (403) detachably connected to the tank body (401), a tilting member (405) provided on the mounting plate (403), a drive motor (404) for driving the tilting member (405) to rotate, and a scraper (402) provided on the tilting member (405). The bottom of the pool body (401) is provided with a drain hole.

10. A cleaning device according to claim 9, characterized in that, The bottom of the pool body (401) is provided with a guide plate (5).

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