A method for preparing high-purity quartz sand from quartz ore

Abstract

This invention discloses a method for preparing high-purity quartz sand from quartz ore, relating to the field of high-purity quartz sand processing. First, a quaternized cation reagent is prepared using benzyl bromide and N,N-dimethyldodecylamine as raw materials. The adsorption of this self-made collector on the quartz surface is the result of the combined effects of electrostatic attraction and multiple forms of hydrogen bonding. The addition of quaternary ammonium and polyhydroxy groups allows for strong physical adsorption of quartz without the need for strong acids. Furthermore, a stable filler layer is formed on the quartz surface, thereby improving the collection effect of the quartz sand. Secondly, the preparation process of this invention is as follows: coarse washing – coarse crushing – direct high-temperature bursting water quenching – medium crushing – microwave heating – fine crushing – acid leaching – magnetic separation – flotation – drying. A segmented, step-by-step treatment is adopted, using different treatment methods for different particle sizes of quartz sand, which is beneficial for removing inclusions in the quartz and results in a larger surface area and better effect compared to acid leaching. The quartz sand prepared by this invention exhibits high purity.

Description

Technical Field

[0001] This invention relates to the field of high-purity quartz sand processing technology, specifically a method for preparing high-purity quartz sand using quartz ore. Background Technology

[0002] Quartz sand is quartz particles formed by crushing and processing quartz stone. Its main component is silicon dioxide, a mineral resource with very stable physical and chemical properties and a wide range of applications. Ordinary quartz sand is used in glass, ceramics, rubber, casting, chemical, plastics metallurgy, construction and other fields. High-purity quartz sand usually refers to quartz sand with a silicon dioxide content of 99.95% or higher. High-purity quartz sand has excellent chemical stability, high insulation and pressure resistance, and extremely low coefficient of volume expansion. Its high-grade products are widely used in large-scale integrated circuits, solar cells, optical fibers, lasers, aerospace, military and other industries. Therefore, separating high-purity quartz sand from quartz mineral resources using various sorting and purification methods has become a research focus.

[0003] During quartz mineralization, many impurity minerals are associated with it, such as feldspar, mica, and clay minerals. The iron and aluminum content in these impurity minerals severely affects the quality of quartz sand. Currently, my country mainly uses high-quality, high-purity vein quartz for processing to produce high-purity quartz sand. This process is relatively simple, but large-scale production often results in quartz sand with excessive impurities, failing to meet usage requirements and leading to low added value. Furthermore, the process requires large amounts of acid for pickling, especially hydrofluoric acid, which puts significant environmental pressure. Therefore, there is an urgent need to find a method to produce high-purity quartz sand with high quartz content and significantly reduced acid consumption. This invention provides a method for preparing high-purity quartz sand from quartz ore to solve the above problems. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing high-purity quartz sand from quartz ore, so as to solve the problems existing in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing high-purity quartz sand using quartz ore, comprising the following preparation steps:

[0006] (1) Coarse washing: Quartz stone with a silica content of not less than 99.3% is placed in a grid box, first soaked in clean water in a washing tank for 3 hours, and then its surface is rinsed with high pressure water to remove impurities. Quartz stone blocks with many surface impurities are taken out and rinsed separately with high pressure water for a second time. The surface of the quartz stone blocks is observed with the naked eye and there are no obvious impurities.

[0007] (2) Coarse crushing: using coarsely washed quartz ore as raw material, crushing it through a jaw crusher to prepare quartz sand with a particle size of 5-15mm, and then screening it through a vibrating screen to obtain quartz sand with a particle size of 5-10mm.

[0008] (3) Direct method for high temperature bursting water quenching: After coarsely crushed particles are calcined in a muffle furnace at 400-1400℃, the particles are taken out and placed in a 1:1 mixture of ice and water for 10-30s, then washed once with deionized water, and then soaked in water at 40-50℃ for 2-4min. After taking out the particles, they are washed twice with deionized water and then dried in a vacuum dryer for 2h.

[0009] (4) Medium crushing: The water-quenched quartz sand is medium crushed by a jaw crusher to prepare quartz sand with a particle size of 0.5-5mm. After screening by a vibrating screen, quartz sand with a particle size of 0.5-3mm is obtained.

[0010] (5) Microwave heating: The medium-crushed quartz sand is microwaved at 1000-2000W for 15-45 minutes;

[0011] (6) Fine crushing: The microwave-treated quartz sand is crushed by a fine roller crusher to prepare quartz sand with a particle size of 0.04-0.2mm. After being screened by a vibrating screen, quartz sand with a particle size of 0.06-0.12mm is obtained.

[0012] (7) Acid leaching: Soak the finely crushed quartz sand in a hydrochloric acid aqueous solution with a mass fraction of 15-25% for 1-3 hours. After soaking, filter and rinse with deionized water. Add a sodium carbonate aqueous solution with a mass fraction of 4-6% and stir for 0.5-0.8 hours. After the process, filter and rinse the filtered quartz sand with deionized water. Then heat and dry for 2-5 hours.

[0013] (8) Magnetic separation: Apply a DC electric field with an intensity of 200-400V / cm for 1-2 hours, and then apply a magnetic field with an intensity of 5000-7000GS to perform magnetic separation in the magnetic separator.

[0014] (9) Flotation: Quartz sand is placed in a 40wt% formic acid aqueous solution to prepare a slurry. 15% hydrochloric acid is added to adjust the pH of the slurry to 2-4. The slurry is stirred and sonicated for 5-15 minutes. 250g / t of self-made collector is added to the slurry and stirred for 5-15 minutes. An equal volume of deionized water at 30-35℃ is injected into the slurry, and a frother is added at a dosage of 90g / t. The slurry is stirred and sonicated for 10-20 minutes. After flotation, the quartz sand is washed with deionized water until neutral.

[0015] (10) Drying: The cleaned quartz sand is dried at 200-300℃ for 4-10 hours using a far-infrared dryer to obtain high-purity quartz sand.

[0016] Furthermore, in step (3), the vacuum degree of the vacuum dryer is -0.095MPa-0.01MPa and the drying temperature is 60℃.

[0017] Furthermore, in step (7), the solid-liquid ratio of quartz sand to hydrochloric acid solution is 1:1.2-1.4.

[0018] Furthermore, in step (7), the solid-liquid ratio of quartz sand to sodium carbonate solution is 1:1.2-1.6.

[0019] Furthermore, the heating and drying in step (7) is carried out at 200-300℃.

[0020] Furthermore, the magnetic separation temperature in step (8) is 150-250℃.

[0021] Furthermore, in step (9), the ratio of quartz sand to formic acid aqueous solution is 1:0.5-2.

[0022] Furthermore, in step (9), the stirring speed is 200-300 rpm and the ultrasonic power is 40-60 kHz.

[0023] Furthermore, the method for preparing the self-made collector in step (9) is as follows: N,N-dimethyldodecylamine and benzyl bromide are placed in a reactor at a molar ratio of 1:1.4-3.0. During the quaternization process, the reactor temperature is maintained at 80-120℃, the reactor pressure is maintained at 0.1-0.64MPa, the reaction time is 3-5h, the pressure is reduced to 1.4-2.0kPa, and distillation is carried out at 50-150℃ for 30-120min. During the reaction, excess reaction gas is removed by purging with inert gas. After the reaction is completed, the self-made collector is obtained.

[0024] Furthermore, the foaming agent in step (9) is triethanolamine dodecylbenzenesulfonate.

[0025] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0026] This invention uses a self-made collector for flotation and performs segmented, stepped crushing and purification of quartz ore to achieve the effect of producing quartz sand with high purity.

[0027] First, a quaternized cation reagent was prepared using benzyl bromide and N,N-dimethyldodecylamine as raw materials. The terminal bromine functional groups on this reagent are universal and can react with tertiary amine compounds to form quaternary ammonium salts. This reagent was used to prepare the self-made collector of this invention to improve the recovery rate of quartz sand. The adsorption of the self-made collector on the quartz surface is the result of the combined effects of electrostatic attraction and multiple forms of hydrogen bonding. Based on the dodecylamine collector, quaternary ammonium groups and polyhydroxy groups were added, thus enabling the cations to have a strong physical adsorption capacity for quartz without the need for strong acid conditions during the collection process, achieving collection through electrostatic adsorption. Simultaneously, the multiple forms of hydrogen bonding not only enhance the adsorption of the self-made collector on the quartz surface, synergistically improving the collection effect with quartz sand through hydrogen bonding forces, but also form a stable filler layer on the quartz surface. The long carbon chains of the quaternary ammonium salt organic matter also enhance the hydrophobicity of the quartz surface, thereby improving the collection effect of quartz sand and preparing high-purity quartz sand.

[0028] Secondly, the preparation process of this invention is as follows: coarse washing - coarse crushing - direct high-temperature bursting water quenching - medium crushing - microwave heating - fine crushing - acid leaching - magnetic separation - flotation - drying. A segmented, step-by-step treatment is adopted, using different treatment methods for different particle sizes of quartz sand. During the direct heating process after coarse crushing, the overall high temperature of the quartz allows for more effective overall expansion and contraction, making it easier for inclusions inside and outside the quartz sand to burst. After medium crushing, the use of substances with different dielectric constants during heating creates a larger local temperature difference, causing more cracks on the surface of medium-sized quartz crystals. This effectively promotes the dissociation of mineral monomers and increases the reaction area of ​​impurity minerals, which is beneficial for removing inclusions from the quartz. Finally, after fine crushing, acid leaching is performed. The fine quartz sand particles are more easily soaked in acid to remove impurities, and the larger surface area of ​​acid leaching results in a better effect. After this layered treatment, the quartz sand prepared by this invention has higher purity. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1; (1) Coarse washing: Quartz stone with a silica content of not less than 99.3% is placed in a grid box, first soaked in clean water in a washing pool for 3 hours, and then its surface is washed with high pressure water to remove impurities. Quartz ore blocks with many surface impurities are taken out and washed separately with high pressure water to remove impurities. The surface of the quartz ore blocks is observed with the naked eye and there are no obvious impurities.

[0031] (2) Coarse crushing: using coarsely washed quartz ore as raw material, crushing it through a jaw crusher to prepare quartz sand with a particle size of 5-15mm, and then screening it through a vibrating screen to obtain a particle size of 5-10mm.

[0032] (3) Direct method for high temperature bursting water quenching: After the coarsely crushed particles are calcined in a muffle furnace at 400℃, the particles are taken out and placed in a 1:1 mixture of ice and water for 10s, then washed once with deionized water, and then soaked in water at 40℃ for 2min. After the particles are taken out and washed twice with deionized water, they are dried in a vacuum dryer for 2h with a vacuum degree of -0.095MPa and a drying temperature of 60℃.

[0033] (4) Medium crushing: The water-quenched quartz sand is medium crushed by a jaw crusher to prepare quartz sand with a particle size of 0.5-5mm. After screening by a vibrating screen, quartz sand with a particle size of 0.5-3mm is obtained.

[0034] (5) Microwave heating: The crushed quartz sand is microwaved at 1000W for 15 minutes;

[0035] (6) Fine crushing: The microwave-treated quartz sand is crushed by a fine roller crusher to prepare quartz sand with a particle size of 0.04-0.2mm. After being screened by a vibrating screen, quartz sand with a particle size of 0.06-0.12mm is obtained.

[0036] (7) Acid leaching: The finely crushed quartz sand is soaked in a 15% hydrochloric acid aqueous solution for 1 hour. The solid-liquid ratio of quartz sand to hydrochloric acid solution is 1:1.2. After soaking, the sand is filtered, rinsed with deionized water, and then a 4% sodium carbonate aqueous solution is added and stirred for 0.5 hours. The solid-liquid ratio of quartz sand to sodium carbonate solution is 1:1.2. After the process is completed, the sand is filtered, rinsed with deionized water, and then heated and dried for 2 hours at a temperature of 200℃.

[0037] (8) Magnetic separation: Apply a DC electric field with an intensity of 200V / cm for 1 hour at a temperature of 150℃, and then apply a magnetic field with an intensity of 5000GS to perform magnetic separation in the magnetic separator.

[0038] (9) Flotation: Quartz sand is placed in a 40 wt% formic acid aqueous solution to prepare a slurry. The ratio of quartz sand to formic acid aqueous solution is 1:0.5. 15% hydrochloric acid is added to adjust the pH of the slurry to 2. The slurry is stirred and sonicated for 5 min at a stirring speed of 200 rpm and an ultrasonic power of 40 kHz. 250 g / t of self-made collector is added to the slurry and stirring is continued for 5 min. An equal volume of deionized water at 30°C is injected into the slurry, and a foaming agent, triethanolamine dodecylbenzenesulfonate, is added to the slurry at a dosage of 90 g / t. The slurry is stirred and sonicated for 10 min. The stirring speed was 200 rpm and the ultrasonic power was 40 kHz. After flotation, the quartz sand was washed with deionized water until neutral. The preparation method of the self-made collector was as follows: N,N-dimethyldodecylamine and benzyl bromide were placed in a reactor at a molar ratio of 1:1.4. During the quaternization process, the reactor temperature was maintained at 80℃ and the reactor pressure was maintained at 0.1 MPa for 3 hours. Then the pressure was reduced to 1.4 kPa and distilled at 100℃ for 30 minutes. During the reaction, excess reaction gas was removed by purging with inert gas. After the reaction was completed, the self-made collector was obtained.

[0039] (10) Drying: The cleaned quartz sand was dried at 200℃ for 4 hours using a far-infrared dryer to obtain high-purity quartz sand.

[0040] Example 2; (1) Coarse washing: Quartz stone with a silica content of not less than 99.3% is placed in a grid box, first soaked in clean water in a washing pool for 3 hours, and then its surface is rinsed with high pressure water to remove impurities. Quartz ore blocks with many surface impurities are taken out and rinsed separately with high pressure water to remove impurities. The surface of the quartz ore blocks is observed with the naked eye and there are no obvious impurities.

[0041] (2) Coarse crushing: using coarsely washed quartz ore as raw material, crushing it through a jaw crusher to prepare quartz sand with a particle size of 5-15mm, and then screening it through a vibrating screen to obtain quartz sand with a particle size of 5-10mm.

[0042] (3) Direct method for high temperature bursting water quenching: After coarsely crushed particles are calcined in a muffle furnace at 900℃, the particles are taken out and placed in a 1:1 mixture of ice and water for 20s, then washed once with deionized water, and then soaked in water at 45℃ for 3min. After taking out the particles, they are washed twice with deionized water and then dried in a vacuum dryer for 2h with a vacuum degree of -0.095MPa and a drying temperature of 60℃.

[0043] (4) Medium crushing: The water-quenched quartz sand is medium crushed by a jaw crusher to prepare quartz sand with a particle size of 0.5-5mm. After screening by a vibrating screen, quartz sand with a particle size of 0.5-3mm is obtained.

[0044] (5) Microwave heating: The crushed quartz sand is microwaved at 1500W for 30 minutes;

[0045] (6) Fine crushing: The microwave-treated quartz sand is crushed by a fine roller crusher to prepare quartz sand with a particle size of 0.12 mm. After being screened by a vibrating screen, quartz sand with a particle size of 0.09 mm is obtained.

[0046] (7) Acid leaching: The finely crushed quartz sand is soaked in a 20% hydrochloric acid aqueous solution for 2 hours. The solid-liquid ratio of quartz sand to hydrochloric acid solution is 1:1.3. After soaking, the sand is filtered, rinsed with deionized water, and then a 5% sodium carbonate aqueous solution is added and stirred for 0.65 hours. The solid-liquid ratio of quartz sand to sodium carbonate solution is 1:1.4. After the process is completed, the sand is filtered, rinsed with deionized water, and then heated and dried for 3.5 hours at a temperature of 250°C.

[0047] (8) Magnetic separation: Apply a DC electric field with an intensity of 300V / cm for 1.5h and a temperature of 200℃, and then apply a magnetic field with an intensity of 6000GS in the magnetic separator for magnetic separation.

[0048] (9) Flotation: Quartz sand was placed in a 40 wt% formic acid aqueous solution to prepare a slurry. The ratio of quartz sand to formic acid aqueous solution was 1:1.25. Hydrochloric acid with a mass fraction of 15% was added to adjust the pH of the slurry to 3. The slurry was stirred and sonicated for 10 min at a stirring speed of 250 rpm and an ultrasonic power of 50 kHz. 250 g / t of self-made collector was added to the slurry and stirring was continued for 10 min. An equal volume of deionized water at 32°C was injected into the slurry, and frother triethanolamine dodecylbenzenesulfonate salt was added to the slurry at a dosage of 90 g / t. The slurry was stirred and sonicated for 15 min. The stirring speed was 250 rpm and the ultrasonic power was 50 kHz. After flotation, the quartz sand was washed with deionized water until neutral. The preparation method of the self-made collector was as follows: N,N-dimethyldodecylamine and benzyl bromide were placed in a reactor at a molar ratio of 1:2.2. During the quaternization process, the reactor temperature was maintained at 100℃ and the reactor pressure was maintained at 0.37 MPa for 4 hours. Then the pressure was reduced to 1.7 kPa and distilled at 100℃ for 75 minutes. During the reaction, excess reaction gas was removed by purging with inert gas. After the reaction was completed, the self-made collector was obtained.

[0049] (10) Drying: The cleaned quartz sand was dried at 250°C for 7 hours using a far-infrared dryer to obtain high-purity quartz sand.

[0050] Example 3; (1) Coarse washing: Quartz stone with a silica content of not less than 99.3% is placed in a grid box, first soaked in clean water in a washing tank for 3 hours, and then its surface is washed with high pressure water to remove impurities. Quartz ore blocks with many surface impurities are taken out and washed separately with high pressure water to remove impurities. The surface of the quartz ore blocks is observed with the naked eye and there are no obvious impurities.

[0051] (2) Coarse crushing: using coarsely washed quartz ore as raw material, crushing it through a jaw crusher to prepare quartz sand with a particle size of 5-15mm, and then screening it through a vibrating screen to obtain quartz sand with a particle size of 5-10mm.

[0052] (3) Direct method for high temperature bursting water quenching: After coarsely crushed particles are calcined in a muffle furnace at 1400℃, the particles are taken out and placed in a 1:1 mixture of ice and water for quenching for 30s, then washed once with deionized water, and then soaked in water at 50℃ for 4min. After taking out the particles, they are washed twice with deionized water and then dried in a vacuum dryer for 2h at a vacuum degree of 0.01MPa and a drying temperature of 60℃.

[0053] (4) Medium crushing: The water-quenched quartz sand is medium crushed by a jaw crusher to prepare quartz sand with a particle size of 0.5-5mm. After screening by a vibrating screen, quartz sand with a particle size of 0.5-3mm is obtained.

[0054] (5) Microwave heating: The crushed quartz sand is microwaved at 2000W for 45 minutes;

[0055] (6) Fine crushing: The microwave-treated quartz sand is crushed by a fine roller crusher to prepare quartz sand with a particle size of 0.04-0.2mm. After being screened by a vibrating screen, quartz sand with a particle size of 0.06-0.12mm is obtained.

[0056] (7) Acid leaching: The finely crushed quartz sand is soaked in a 25% hydrochloric acid aqueous solution for 3 hours. The solid-liquid ratio of quartz sand to hydrochloric acid solution is 1:1.4. After soaking, the sand is filtered, rinsed with deionized water, and then a 6% sodium carbonate aqueous solution is added and stirred for 0.8 hours. The solid-liquid ratio of quartz sand to sodium carbonate solution is 1:1.6. After the process is completed, the sand is filtered, rinsed with deionized water, and then heated and dried for 5 hours at a temperature of 300℃.

[0057] (8) Magnetic separation: Apply a DC electric field with an intensity of 400V / cm for 2 hours at a temperature of 250℃, and then apply a magnetic field with an intensity of 7000GS in the magnetic separator.

[0058] (9) Flotation: Quartz sand was placed in a 40 wt% formic acid aqueous solution to prepare a slurry. The ratio of quartz sand to formic acid aqueous solution was 1:2. 15% hydrochloric acid was added to adjust the pH of the slurry to 4. The slurry was stirred and sonicated for 15 min at a stirring speed of 300 rpm and an ultrasonic power of 60 kHz. 250 g / t of self-made collector was added to the slurry, and stirring was continued for 15 min. An equal volume of deionized water at 35°C was injected into the slurry, and frother triethanolamine dodecylbenzenesulfonate salt was added to the slurry at a dosage of 90 g / t. The slurry was stirred and sonicated for 20 min. The speed was 300 rpm and the ultrasonic power was 60 kHz. After flotation, the quartz sand was washed with deionized water until neutral. The preparation method of the self-made collector was as follows: N,N-dimethyldodecylamine and benzyl bromide were placed in a reactor at a molar ratio of 1:3.0. During the quaternization process, the reactor temperature was maintained at 120℃ and the reactor pressure was maintained at 0.64 MPa for 5 h. Then the pressure was reduced to 2.0 kPa and distilled at 150℃ for 120 min. During the reaction, excess reaction gas was removed by purging with inert gas. After the reaction was completed, the self-made collector was obtained.

[0059] (10) Drying: The cleaned quartz sand was dried at 300℃ for 10 hours using a far-infrared dryer to obtain high-purity quartz sand.

[0060] Comparative Example 1;

[0061] The difference between Comparative Example 5 and Example 2 is that steps (4) and (6) are omitted. The preparation process is changed to: (1) Coarse washing: Quartz stone with a silica content of not less than 99.3% is placed in a grid box, first soaked in clean water in a washing pool for 3 hours, and then its surface is washed with high pressure water to remove impurities. Quartz ore blocks with many surface impurities are taken out and washed separately with high pressure water to remove impurities. The surface of the quartz ore blocks is observed with the naked eye and there are no obvious impurities.

[0062] (2) Crushing: The coarsely washed quartz ore is crushed by a jaw crusher to prepare quartz sand with a particle size of 0.5-5mm. After being screened by a vibrating screen, quartz sand with a particle size of 0.5-3mm is obtained. Then, it is crushed by a fine roller crusher to prepare quartz sand with a particle size of 0.12mm. After being screened by a vibrating screen, quartz sand with a particle size of 0.09mm is obtained.

[0063] (3) Direct high temperature bursting water quenching: After the crushed particles are calcined in a muffle furnace at 900℃, the particles are taken out and placed in a 1:1 mixture of ice and water for 20s, then washed once with deionized water, and then soaked in water at 45℃ for 3min. After the particles are taken out, they are washed twice with deionized water and then dried in a vacuum dryer for 2h with a vacuum degree of -0.095MPa and a drying temperature of 60℃.

[0064] (4) Microwave heating: Then the quartz sand is microwaved at 1500W for 30 minutes;

[0065] (5) Acid leaching: After microwave heating, the quartz sand was soaked in a 20% hydrochloric acid aqueous solution for 2 hours. The solid-liquid ratio of the quartz sand to the hydrochloric acid solution was 1:1.3. After soaking, the quartz sand was filtered, rinsed with deionized water, and then a 5% sodium carbonate aqueous solution was added and stirred for 0.65 hours. The solid-liquid ratio of the quartz sand to the sodium carbonate solution was 1:1.4. After the leaching was completed, the quartz sand was filtered, rinsed with deionized water, and then dried at 250°C for 3.5 hours.

[0066] (6) Magnetic separation: Apply a DC electric field with an intensity of 300V / cm for 1.5h and a temperature of 200℃, and then apply a magnetic field with an intensity of 6000GS in the magnetic separator for magnetic separation.

[0067] (7) Flotation: Quartz sand was placed in a 40 wt% formic acid aqueous solution to prepare a slurry. The ratio of quartz sand to formic acid aqueous solution was 1:1.25. 15% hydrochloric acid was added to adjust the pH of the slurry to 3. The slurry was stirred and sonicated for 10 min at a stirring speed of 250 rpm and an ultrasonic power of 50 kHz. 250 g / t of self-made collector was added to the slurry and stirring was continued for 10 min. An equal volume of deionized water at 32°C was injected into the slurry, and frother triethanolamine dodecylbenzenesulfonate was added to the slurry at a dosage of 90 g / t. The slurry was stirred and sonicated for 15 min. The stirring speed was 250 rpm and the ultrasonic power was 50 kHz. After flotation, the quartz sand was washed with deionized water until neutral. The preparation method of the self-made collector was as follows: N,N-dimethyldodecylamine and benzyl bromide were placed in a reactor at a molar ratio of 1:2.2. During the quaternization process, the reactor temperature was maintained at 100℃ and the reactor pressure was maintained at 0.37 MPa. The pressure was reduced to 1.7 kPa and distilled at 100℃ for 75 min. During the reaction, excess reaction gas was removed by purging with inert gas. The reaction time was 4 h. The self-made collector was obtained after the reaction was completed.

[0068] (8) Drying: The cleaned quartz sand was dried at 250°C for 7 hours using a far-infrared dryer to obtain high-purity quartz sand. The remaining steps are the same as in Example 2.

[0069] Comparative Example 2

[0070] The difference between Comparative Example 5 and Example 2 lies in step (9). Step (9) is changed to: flotation: Quartz sand is placed in a 40wt% formic acid aqueous solution to prepare a slurry. The ratio of quartz sand to formic acid aqueous solution is 1:1.25. Hydrochloric acid with a mass fraction of 15% is added to adjust the pH of the slurry to 3. The slurry is stirred and sonicated for 10 minutes at a stirring speed of 250 rpm and a sonic power of 50 kHz. 250 g / t dodecylamine is added to the slurry and stirring is continued for 10 minutes. An equal volume of deionized water at 32°C is injected into the slurry, and a foaming agent, triethanolamine dodecylbenzenesulfonate salt, is added to the slurry at a dosage of 90 g / t. The slurry is stirred and sonicated for 15 minutes at a stirring speed of 250 rpm and a sonic power of 50 kHz. After flotation, the quartz sand is washed with deionized water until neutral. The remaining steps are the same as in Example 2.

[0071] Example of effect

[0072] Table 1 below shows the performance analysis results of preparing high-purity quartz sand using quartz ore according to Examples 1 to 3 and Comparative Examples 1 to 2 of the present invention.

[0073] Table 1

[0074] <![CDATA[ SiO 2(%)]]> <![CDATA[ Al 2 O 3(%)]]> <![CDATA[ F e2 O 3(%)]]> Example 1 99.997 0.0003 0.0002 Example 2 99.999 0.0001 0.0002 Example 3 99.998 0.0002 0.0002 Comparative Example 1 99.985 0.0007 0.0009 Comparative Example 2 99.972 0.0015 0.0013

[0075] A comparison of experimental data on the percentage content of silica in the examples and comparative examples reveals that the present invention uses benzyl bromide and N,N-dimethyldodecylamine as raw materials to prepare a quaternized cation reagent. The terminal bromine functional groups on this reagent are universal and can react with tertiary amine compounds to form quaternary ammonium salts. This allows for the preparation of a self-made collector to improve the recovery rate of quartz sand. The adsorption of the self-made collector on the quartz surface is the result of the combined effects of electrostatic attraction and multiple forms of hydrogen bonding. Based on the dodecylamine collector, quaternary ammonium groups and polyhydroxy groups are added, thus enabling the cations to have a strong physical adsorption capacity for quartz without the need for strong acid conditions during the collection process, achieving collection through electrostatic adsorption. Simultaneously, the multiple forms of hydrogen bonding not only enhance the adsorption of the self-made collector on the quartz surface, synergistically improving the collection effect with quartz sand through hydrogen bonding forces, but also form a stable filler layer on the quartz surface. The long carbon chains of the quaternary ammonium salt organic matter also enhance the hydrophobicity of the quartz surface, thereby improving the collection effect of quartz sand and preparing high-purity quartz sand. Secondly, the preparation process of this invention is as follows: coarse washing - coarse crushing - direct high-temperature bursting water quenching - medium crushing - microwave heating - fine crushing - acid leaching - magnetic separation - flotation - drying. A segmented, step-by-step treatment is adopted, using different treatment methods for different particle sizes of quartz sand. During the direct heating process after coarse crushing, the overall high temperature of the quartz allows for more effective overall expansion and contraction, making it easier for inclusions inside and outside the quartz sand to burst. After medium crushing, the use of substances with different dielectric constants during heating creates a larger local temperature difference, causing more cracks on the surface of medium-sized quartz crystals. This effectively promotes the dissociation of mineral monomers and increases the reaction area of ​​impurity minerals, which is beneficial for removing inclusions from the quartz. Finally, after fine crushing, acid leaching is performed. The fine quartz sand particles are more easily soaked in acid to remove impurities, and the larger surface area of ​​acid leaching results in a better effect. After this layered treatment, the quartz sand prepared by this invention has higher purity.

[0076] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A production method for producing high-purity quartz sand from quartz ore, characterized by comprising the steps of: The preparation steps include the following: ​ (1) coarse washing: the quartzite with a silicon dioxide content of not less than 99.3% is put into a grid box, and then is soaked in clean water in a washing pool for 3 h, and the surface of the quartzite is washed with high-pressure water to remove impurities; the quartzite with more impurities on the surface is taken out and is washed with high-pressure water again, and the surface of the quartzite is observed with naked eyes, and no obvious impurities are found; (2) coarse crushing: the quartzite washed is used as raw material, and is crushed by a jaw crusher to prepare quartz sand with a particle size of 5-15 mm, and the quartz sand with a particle size of 5-10 mm is obtained after screening by a vibrating screen; (3) direct method high-temperature explosion water quenching: the particles after coarse crushing are calcined in a muffle furnace at 400-1400 ℃, and then are taken out and are quenched in ice water with a mixing ratio of 1:1 for 10-30 s, and then are washed once with deionized water, and then are soaked in water at a temperature of 40-50 ℃ for 2-4 min, and then are washed twice with deionized water, and then are dried in a vacuum drying machine for 2 h; (4) medium crushing: the quartz sand after water quenching is crushed by a jaw crusher to prepare quartz sand with a particle size of 0.5-5 mm, and the quartz sand with a particle size of 0.5-3 mm is obtained after screening by a vibrating screen; (5) microwave heating: the quartz sand after medium crushing is treated by microwave with a power of 1000-2000 W for 15-45 min; (6) fine crushing: the quartz sand after microwave treatment is crushed by a fine roller crusher to prepare quartz sand with a particle size of 0.04-0.2 mm, and the quartz sand with a particle size of 0.06-0.12 mm is obtained after screening by a vibrating screen; (7) acid leaching: the quartz sand after fine crushing is soaked in a hydrochloric acid aqueous solution with a mass fraction of 15-25% for 1-3 h, and then is filtered and is washed with deionized water, and then a sodium carbonate aqueous solution with a mass fraction of 4-6% is added and is stirred for 0.5-0.8 h, and then is filtered, and the filtered quartz sand is washed with deionized water and is dried by heating for 2-5 h; (8) magnetic separation: a direct current electric field with a strength of 200-400 V / cm is applied, and the electric field is applied for 1-2 h, and then a magnetic field with a strength of 5000-7000 GS is applied in a magnetic separator. (9) Flotation: N,N-dimethyl dodecylamine, benzyl bromide are put into the reactor according to the molar ratio of 1:1.4-3.0, the reactor temperature is kept at 80-120 DEG C during the quaternary ammonium process, the reactor pressure is kept at 0.1-0.64 MPa, the reaction time is 3-5 h, the pressure is reduced to 1.4-2.0 kPa, and the distillation is carried out at 50-150 DEG C for 30-120 min, inert gas is used to remove excess reaction gas during the reaction, and the self-made collector is prepared at the end of the reaction. The quartz sand is placed in a 40wt% formic acid aqueous solution to prepare a slurry, 15wt% hydrochloric acid is added to adjust the pH of the slurry to 2-4, and stirring and ultrasonic treatment are carried out for 5-15 min; 250 g / t of the self-made collector is added to the slurry, and stirring is carried out for 5-15 min; an equal volume of deionized water at 30-35 DEG C is injected into the slurry, and a foaming agent is added to the slurry according to a dosage of 90 g / t, and stirring and ultrasonic treatment are carried out for 10-20 min; and the quartz sand is washed to neutral with deionized water after flotation; (10) Drying: The quartz sand after washing is dried at 200-300 DEG C for 4-10 h by using a far infrared drying machine to obtain high-purity quartz sand.

2. The method for preparing high purity quartz sand from quartz ore according to claim 1, characterized in that, The vacuum degree of the vacuum drying machine in step (3) is -0.095 MPa-0.01 MPa, and the drying temperature is 60 DEG C.

3. The method for preparing high purity quartz sand from quartz ore according to claim 1, characterized in that, The solid-liquid ratio of the quartz sand to the hydrochloric acid solution in step (7) is 1:1.2-1.

4.

4. The method for preparing high purity quartz sand from quartz ore according to claim 1, characterized in that, The solid-liquid ratio of the quartz sand to the sodium carbonate solution in step (7) is 1:1.2-1.

6.

5. The method for preparing high purity quartz sand from quartz ore according to claim 1, wherein The heating and drying in step (7) is carried out at 200-300 DEG C.

6. The method for preparing high purity quartz sand from quartz ore according to claim 1, wherein, The magnetic separation temperature in step (8) is 150-250 DEG C.

7. The method of claim 1, wherein the method further comprises the steps of: crushing the quartz ore to a size of 0.5 to 2 mm; and washing the crushed quartz ore with water to remove impurities. The ratio of the quartz sand to the formic acid aqueous solution in step (9) is 1:0.5-2.

8. The method for preparing high purity quartz sand from quartz ore according to claim 1, characterized in that, The stirring speed in step (9) is 200-300 rpm, and the ultrasonic power is 40-60 kHz.

9. The method for preparing high-purity quartz sand using quartz ore according to claim 1, characterized in that, The foaming agent in step (9) is dodecyl benzene sulfonic acid triethanolamine salt.