A non-calcination ultrasonic-assisted method for preparing high-purity quartz

Abstract

This invention provides a method for preparing high-purity quartz without roasting using ultrasound-assisted methods, comprising the following steps: S1, crushing, grinding, and classifying the raw quartz ore to obtain a ground sample, followed by magnetic separation and flotation to obtain quartz concentrate; S2, adding the quartz concentrate to a mixed acid solution for isothermal leaching, followed by washing and drying to obtain primary quartz sand; S3, adding the primary quartz sand to an alkaline solution for room-temperature ultrasonic alkaline leaching, followed by washing and drying to obtain intermediate quartz sand; S4, adding the intermediate quartz sand to a phosphoric acid solution for room-temperature ultrasonic acid leaching, followed by washing and drying to obtain high-purity quartz sand. This invention utilizes ultrasound-assisted alkaline solution to induce cracks in the quartz, and then utilizes the cavitation effect of ultrasound and the complexing ability of phosphoric acid to deeply remove impurities, thereby achieving efficient removal of inclusions and lattice defects within quartz particles without high-temperature roasting.

Description

Technical Field

[0001] This invention relates to the field of mineral processing technology, specifically to a method for preparing high-purity quartz without roasting and with ultrasonic assistance. Background Technology

[0002] High-purity quartz (SiO2 purity ≥ 99.99%) has excellent optical properties, corrosion resistance, high temperature resistance and other physicochemical properties.

[0003] However, natural quartz generally contains a large number of impurities (such as independent gangue minerals, inclusions, and lattice substitution impurities), and its complex occurrence state severely restricts its high-end applications. Commonly used impurity removal methods include magnetic separation, flotation, acid leaching, roasting, and combinations thereof. Gangue mineral impurities on the quartz surface can usually be easily removed by physical beneficiation methods such as magnetic separation and flotation, while inclusions and lattice substitution impurities are difficult to remove; usually, roasting-water quenching is required to create crack mass transfer channels, followed by acid leaching for removal. However, high-temperature roasting is energy-intensive, costly, and does not conform to the concept of green manufacturing. Conventional acid leaching has insufficient mass transfer efficiency and cannot effectively penetrate into the cracks, resulting in poor removal of deep impurities. Ultrasonic leaching containing HF is prone to causing equipment corrosion.

[0004] Therefore, it is of great significance to develop a quartz purification method that can efficiently remove deep impurities such as inclusions and lattice substitution impurities without high-temperature calcination. Summary of the Invention

[0005] In view of the technical problems existing in the background art, the present invention provides a method for preparing high-purity quartz without roasting and with ultrasonic assistance, which aims to solve the technical problems of high energy consumption of high-temperature roasting and difficulty in efficient penetration and removal of impurities in deep cracks by conventional acid leaching in existing quartz sand purification technology.

[0006] In a first aspect, the present invention provides a method for preparing high-purity quartz without calcination using ultrasound-assisted preparation, comprising the following steps: S1. The raw quartz ore is crushed, ground, and classified to obtain a ground sample, which is then subjected to magnetic separation and flotation to obtain quartz concentrate. S2. Quartz concentrate is added to a mixed acid solution for constant temperature leaching, and after washing and drying, primary quartz sand is obtained. S3. Primary quartz sand is added to an alkaline solution and subjected to ultrasonic alkaline leaching at room temperature. After washing and drying, intermediate quartz sand is obtained. S4. Add medium-grade quartz sand to phosphoric acid solution for ultrasonic acid leaching at room temperature, and then wash and dry to obtain high-purity quartz sand.

[0007] Preferably, in step S1, the particle size of the grinding sample is -60 mesh to +160 mesh.

[0008] Preferably, in step S2, the mixed acid solution includes 1~4 mol / L hydrofluoric acid, 1~4 mol / L hydrochloric acid and 1~4 mol / L nitric acid.

[0009] Preferably, in step S2, the liquid-solid ratio of quartz concentrate to mixed acid solution is (2~5) mL:1g.

[0010] Preferably, in step S2, the constant temperature leaching temperature is 60℃~100℃, and the constant temperature leaching time is 5~10h.

[0011] Preferably, in step S3, the concentration of alkali in the alkaline solution is 0.2~1.5 mol / L.

[0012] Preferably, in step S3, the liquid-solid ratio of primary quartz sand to alkaline solution is (2~6) mL:1g.

[0013] Preferably, in step S3, the ultrasonic alkaline immersion time is 30~120min, and the ultrasonic alkaline immersion power is 100~500W.

[0014] Preferably, in step S4, the concentration of the phosphoric acid solution is 1~8 mol / L; the liquid-solid ratio of medium-grade quartz sand to phosphoric acid solution is (2~7) mL:1g.

[0015] Preferably, in step S4, the ultrasonic acid leaching time is 30~180min and the ultrasonic acid leaching power is 100~500W.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The method for preparing high-purity quartz without calcination using ultrasound-assisted leaching provided by this invention adopts an "ultrasound + alkaline solution" pretreatment process, replacing the energy-intensive high-temperature calcination step. Ultrasound-assisted leaching does not require an external heat source, which can significantly reduce production energy consumption. This process utilizes the cavitation effect of ultrasound in conjunction with the selective dissolution of quartz lattice defects by the alkaline solution, effectively expanding the crack depth of quartz sand. This not only solves the problem of difficult traditional acid leaching to a certain extent, but also establishes an efficient mass transfer channel for subsequent removal of deep inclusions and lattice impurities.

[0017] (2) In the ultrasonic leaching stage of this invention, phosphoric acid with low volatility and strong complexing ability is used to replace volatile and highly corrosive acid for deep impurity removal. Through crack expansion pretreatment, the contact efficiency of phosphoric acid is improved, selective impurity removal is achieved, the acid mist hazard in the operating environment is reduced, and the corrosion of equipment is reduced.

[0018] (3) The purity of SiO2 in the quartz sand prepared by the method provided by the present invention can be stably reached above 99.99%, the total impurity content is significantly reduced, and the yield is high. Attached Figure Description

[0019] Figure 1 This is a process flow diagram of the method for preparing high-purity quartz without calcination using ultrasound-assisted methods according to the present invention. Figure 2 The quartz ore in Example 3 of this invention ( Figure 2 a) High-purity quartz sand in Example 3 ( Figure 2 c) and the high-purity quartz sand in Comparative Example 3 ( Figure 2 b) SEM image. Detailed Implementation

[0020] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0021] To address the technical problems of high energy consumption during high-temperature calcination and the difficulty of efficient penetration and removal of impurities from deep cracks in conventional acid leaching in existing quartz sand purification technologies, this invention provides a method for preparing high-purity quartz without calcination using ultrasound-assisted methods. First, most impurities are removed using conventional methods. Then, an ultrasonic-assisted alkaline solution is used to create crack channels in the quartz. Finally, the cavitation effect of ultrasound and the complexing ability of phosphoric acid are used for deep impurity removal. Thus, without high-temperature calcination, efficient removal of inclusions and lattice defects within the quartz particles is achieved.

[0022] Please refer to the appendix. Figure 1 In a first aspect, embodiments of the present invention provide a method for preparing high-purity quartz without calcination using ultrasound-assisted methods, comprising the following steps: S1. The raw quartz ore is crushed, ground, and classified to obtain a ground sample, which is then subjected to magnetic separation and flotation to obtain quartz concentrate. S2. Quartz concentrate is added to a mixed acid solution for constant temperature leaching, and after washing and drying, primary quartz sand is obtained. S3. Primary quartz sand is added to an alkaline solution and subjected to ultrasonic alkaline leaching at room temperature. After washing and drying, intermediate quartz sand is obtained. S4. Add medium-grade quartz sand to phosphoric acid solution for ultrasonic acid leaching at room temperature, and then wash and dry to obtain high-purity quartz sand.

[0023] In the technical solution of this invention embodiment, the quartz ore is first crushed, ground, and classified in step S1 to process it into a grinding sample with a suitable particle size for subsequent magnetic separation and flotation. Magnetic separation can effectively remove magnetic mineral impurities such as magnetite and hematite from the quartz ore. Flotation utilizes the differences in the physicochemical properties of the mineral surface and adds appropriate flotation reagents to separate quartz from other non-magnetic gangue minerals, thereby obtaining a preliminarily purified quartz concentrate. In step S2, the quartz concentrate is leached at a constant temperature using a mixed acid solution to dissolve and remove soluble metal oxides and other impurities from the surface and shallow layers of the quartz concentrate. In step S3, the primary quartz sand is placed in an alkaline solution... In step S3, room-temperature ultrasonic alkaline leaching is performed in the liquid. Under the cavitation effect of ultrasound, a large number of microbubbles are generated in the liquid. When these bubbles burst, they release enormous energy, impacting the surface and interior of the quartz sand. Simultaneously, the alkaline solution selectively dissolves some defects in the quartz lattice. The synergistic effect of these two processes effectively expands the existing microcracks in the quartz sand and promotes the formation of new cracks, creating efficient mass transfer channels for subsequent deep impurity removal. Finally, in step S4, utilizing the strong complexing ability of phosphoric acid, with the assistance of ultrasound, it can penetrate deep into the interior of the quartz sand through the crack channels formed in step S3, undergoing a complexation reaction with inclusions and lattice-substituted impurities, dissolving them from the quartz lattice, thus completing the purification of the quartz sand. The entire process does not require high-temperature calcination, significantly reducing energy consumption. At the same time, the use of phosphoric acid instead of traditional highly corrosive acids such as hydrofluoric acid reduces corrosion of equipment and environmental pollution, achieving efficient and green high-purity quartz preparation.

[0024] In this invention, no special limitation is made on the magnetic separation and flotation methods; conventional magnetic separators and flotation processes in the art can be used.

[0025] Furthermore, in some embodiments, in step S1, the particle size of the grinding sample is -60 mesh to +160 mesh.

[0026] Furthermore, in some embodiments, in step S2, the mixed acid solution includes 1~4 mol / L hydrofluoric acid, 1~4 mol / L hydrochloric acid, and 1~4 mol / L nitric acid.

[0027] Furthermore, in some embodiments, in step S2, the liquid-to-solid ratio of quartz concentrate to mixed acid solution is (2~5) mL:1g.

[0028] Furthermore, in some embodiments, in step S2, the temperature of the constant temperature leaching is 60°C to 100°C, and the leaching time is 5 to 10 hours.

[0029] Furthermore, in some embodiments, in step S3, the concentration of alkali in the alkaline solution is 0.2~1.5 mol / L.

[0030] Furthermore, in some embodiments, in step S3, the alkaline solution includes at least one of sodium hydroxide solution and potassium hydroxide solution.

[0031] Furthermore, in some embodiments, in step S3, the liquid-to-solid ratio of primary quartz sand to alkaline solution is (2~6) mL:1g.

[0032] Furthermore, in some embodiments, in step S3, the ultrasonic alkaline immersion time is 30~120min, and the ultrasonic alkaline immersion power is 100~500W.

[0033] Furthermore, in some embodiments, in step S4, the concentration of the phosphoric acid solution is 1~8 mol / L.

[0034] Furthermore, in some embodiments, in step S4, the liquid-to-solid ratio of intermediate-grade quartz sand to phosphoric acid solution is (2~7) mL:1g.

[0035] Furthermore, in some embodiments, in step S4, the ultrasonic acid leaching time is 30~180min, and the ultrasonic acid leaching power is 100~500W.

[0036] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0037] In this invention, no special limitation is made on the magnetic separation and flotation methods; conventional magnetic separators and flotation processes in the art can be used.

[0038] In the following embodiments and comparative examples of the present invention, the flotation process described in step (1) adopts a three-stage reverse flotation, which is used to remove iron-containing minerals, mica and feldspar respectively, and specifically includes the following steps: First stage reverse flotation: Sodium carbonate (Na2CO3) is added to the slurry to adjust the pH value to 7-8; then sodium oleate is added at a dosage of 160 g / t, and methyl isobutyl methanol (MIBC) is added as a frother at a dosage of 50 g / t; the tank contains the first stage concentrate after the removal of iron-containing minerals; Second-stage reverse flotation: The first-stage concentrate is added to the second-stage flotation. H2SO4 is used as a pH adjuster to adjust the pulp pH to 3. A combination inhibitor of starch and water glass is added at a dosage of 80 g / t. After stirring for 2-5 minutes, the collector dodecylamine is added at a dosage of 100 g / t. The frother is MIBC at a dosage of 50 g / t. Mica is removed by the second-stage reverse flotation. Third-stage reverse flotation: The concentrate from the second-stage reverse flotation is added to another flotation cell. Hydrofluoric acid is used as a pH adjuster and activator to adjust the pH of the pulp to 2. A combined inhibitor of starch and water glass is added at a dosage of 80 g / t. After stirring for 2-5 minutes, the collector dodecylamine is added at a dosage of 100 g / t. The frother is MIBC at a dosage of 50 g / t. Feldspar is removed by the third-stage reverse flotation. All the above-mentioned reverse flotation processes were carried out under the conditions of a pulp weight concentration of 30% and a flotation machine impeller speed of 1400 r / min.

[0039] Example 1 A method for preparing high-purity quartz without calcination using ultrasound-assisted methods, comprising the following specific steps: (1) The raw quartz ore from a vein in Hubei Province was subjected to coarse crushing, wet screening for desliming, drying, fine crushing, ball milling and screening to obtain a grinding sample with a particle size range of -60~+160 mesh. After passing through conventional physical beneficiation processes such as magnetic separation and flotation, the quartz concentrate was dried. (2) Prepare leaching solution A (containing 2 mol / L hydrofluoric acid + 2 mol / L hydrochloric acid + 2 mol / L nitric acid), weigh 30g of the above quartz concentrate and place it in a reaction vessel, add leaching solution A, the liquid-solid ratio is 3mL:1g, carry out constant temperature leaching, the leaching temperature is 80℃, stir and react for 6 hours, wash thoroughly with ultrapure water, filter and dry to obtain primary quartz sand; (3) Prepare leachate B (1 mol / L sodium hydroxide solution), place primary quartz sand in a reaction vessel, add leachate B, control the liquid-solid ratio to be 5 mL: 1 g, and perform ultrasonic alkaline leaching pretreatment using ultrasonic thermal effect and cavitation effect. The ultrasonic power is 300 W and the ultrasonic time is 60 minutes. After ultrasonic alkaline leaching is completed, wash thoroughly with ultrapure water, filter and dry to obtain intermediate quartz sand. (4) The obtained intermediate-grade quartz sand was placed in another reaction tank, and leaching solution C (5 mol / L phosphoric acid solution) was added for ultrasonic leaching of phosphoric acid to remove impurities. The liquid-solid ratio was controlled at 5 mL:1 g, the ultrasonic power was 300 W, and the ultrasonic leaching time was 120 minutes. After the reaction was completed, the sand was thoroughly washed with ultrapure water and dried to obtain high-purity quartz sand with a final purity of 99.991%.

[0040] Example 2 A method for preparing high-purity quartz without calcination using ultrasound-assisted methods, comprising the following specific steps: (1) The raw quartz ore from a vein in Hubei Province was subjected to coarse crushing, wet screening for desliming, drying, fine crushing, ball milling and screening to obtain a grinding sample with a particle size range of -60~+160 mesh. After passing through conventional physical beneficiation processes such as magnetic separation and flotation, the quartz concentrate was dried. (2) Prepare leaching solution A (containing 4 mol / L hydrofluoric acid + 3 mol / L hydrochloric acid + 3 mol / L nitric acid), weigh 30g of the above quartz concentrate and place it in a reaction vessel, add leaching solution A, the liquid-solid ratio is 3mL:1g, carry out constant temperature leaching, the leaching temperature is 80℃, stir and react for 8 hours, wash thoroughly with ultrapure water, filter and dry to obtain primary quartz sand; (3) Prepare leachate B (2 mol / L sodium hydroxide solution), place primary quartz sand in a reaction vessel, add leachate B, control the liquid-solid ratio to be 5 mL: 1 g, and perform ultrasonic alkaline leaching pretreatment using ultrasonic thermal effect and cavitation effect. The ultrasonic power is 500 W and the ultrasonic time is 90 minutes. After ultrasonic alkaline leaching is completed, wash thoroughly with ultrapure water, filter and dry to obtain intermediate quartz sand. (4) The obtained intermediate-grade quartz sand was placed in another reaction tank, and leaching solution C (6 mol / L phosphoric acid solution) was added for phosphoric acid ultrasonic leaching to remove impurities. The liquid-solid ratio was controlled at 5 mL:1 g, the ultrasonic power was 500 W, and the ultrasonic leaching time was 180 minutes. After the reaction was completed, it was thoroughly washed with ultrapure water and dried to obtain high-purity quartz sand with a final purity of 99.990%.

[0041] Example 3 A method for preparing high-purity quartz without calcination using ultrasound-assisted methods, comprising the following specific steps: (1) The raw quartzite ore from Gansu was subjected to coarse crushing, wet screening, desliming, drying, fine crushing, ball milling and screening to obtain a grinding sample with a particle size range of -60~+160 mesh. After passing through conventional physical beneficiation processes such as magnetic separation and flotation, the quartz concentrate was dried. (2) Prepare leaching solution A (containing 2 mol / L hydrofluoric acid + 2 mol / L hydrochloric acid + 2 mol / L nitric acid), weigh 30g of the above quartz concentrate and place it in a reaction vessel, add leaching solution A, the liquid-solid ratio is 3mL:1g, carry out constant temperature leaching, the leaching temperature is 80℃, stir and react for 6 hours, wash thoroughly with ultrapure water, filter and dry to obtain primary quartz sand; (3) Prepare leachate B (1 mol / L sodium hydroxide solution), place primary quartz sand in a reaction vessel, add leachate B, control the liquid-solid ratio to be 5 mL: 1 g, and perform ultrasonic alkaline leaching pretreatment using ultrasonic thermal effect and cavitation effect. The ultrasonic power is 300 W and the ultrasonic time is 60 minutes. After ultrasonic alkaline leaching is completed, wash thoroughly with ultrapure water, filter and dry to obtain intermediate quartz sand. (4) The obtained intermediate-grade quartz sand was placed in another reaction tank, and leaching solution C (5 mol / L phosphoric acid solution) was added for phosphoric acid ultrasonic leaching to remove impurities. The liquid-solid ratio was controlled at 5 mL:1 g, the ultrasonic power was 300 W, and the ultrasonic leaching time was 120 minutes. After the reaction was completed, the sand was thoroughly washed with ultrapure water and dried to obtain high-purity quartz sand with a final purity of 99.990%.

[0042] Comparative Example 1 (low concentration, short time) A method for preparing high-purity quartz, the specific steps of which are as follows: (1) The raw quartz ore from a vein in Hubei Province was subjected to coarse crushing, wet screening for desliming, drying, fine crushing, ball milling and screening to obtain a grinding sample with a particle size range of -60~+160 mesh. After passing through conventional physical beneficiation processes such as magnetic separation and flotation, the quartz concentrate was dried. (2) Prepare leaching solution A (containing 1 mol / L hydrofluoric acid + 1 mol / L hydrochloric acid + 1 mol / L nitric acid), weigh 30g of the above quartz concentrate and place it in a reaction vessel, add leaching solution A, the liquid-solid ratio is 1mL:1g, carry out constant temperature leaching, the leaching temperature is 80℃, stir and react for 4 hours, wash thoroughly with ultrapure water, filter and dry to obtain primary quartz sand; (3) Prepare leachate B (0.5 mol / L sodium hydroxide solution), place primary quartz sand in a reaction vessel, add leachate B, control the liquid-solid ratio to be 5 mL: 1 g, and perform ultrasonic alkaline leaching pretreatment using ultrasonic thermal effect and cavitation effect. The ultrasonic power is 200 W and the ultrasonic time is 30 minutes. After ultrasonic alkaline leaching is completed, wash thoroughly with ultrapure water, filter and dry to obtain intermediate quartz sand. (4) The obtained intermediate-grade quartz sand was placed in another reaction tank, and leaching solution C (1 mol / L phosphoric acid solution) was added to remove impurities by ultrasonic leaching with phosphoric acid. The liquid-solid ratio was controlled at 5 mL:1 g, the ultrasonic power was 100 W, and the ultrasonic leaching time was 60 minutes. After the reaction was completed, the sand was thoroughly washed with ultrapure water and dried to obtain high-purity quartz sand with a final purity of 99.984%.

[0043] Comparative Example 2 (without alkali leaching) A method for preparing high-purity quartz, the specific steps of which are as follows: (1) The raw quartz ore from a vein in Hubei Province was subjected to coarse crushing, wet screening for desliming, drying, fine crushing, ball milling and screening to obtain a grinding sample with a particle size range of -60~+160 mesh. After passing through conventional physical beneficiation processes such as magnetic separation and flotation, the quartz concentrate was dried. (2) Prepare leaching solution A (containing 2 mol / L hydrofluoric acid + 2 mol / L hydrochloric acid + 2 mol / L nitric acid), weigh 30g of the above quartz concentrate and place it in a reaction vessel, add leaching solution A, the liquid-solid ratio is 3mL:1g, carry out constant temperature leaching, the leaching temperature is 80℃, stir and react for 6 hours, wash thoroughly with ultrapure water, filter and dry to obtain primary quartz sand; (3) Place the primary quartz sand in another reaction tank, add leaching solution C (5 mol / L phosphoric acid solution) for phosphoric acid ultrasonic leaching to remove impurities, control the liquid-solid ratio to be 5 mL: 1 g, the ultrasonic power to be 300 W, the ultrasonic leaching time to be 120 minutes, and after the reaction is completed, wash thoroughly with ultrapure water and dry to obtain high-purity quartz sand with a final purity of 99.987%.

[0044] Comparative Example 3 (without ultrasound) A method for preparing high-purity quartz, the specific steps of which are as follows: (1) The raw quartz ore from a vein in Hubei Province was subjected to coarse crushing, wet screening for desliming, drying, fine crushing, ball milling and screening to obtain a grinding sample with a particle size range of -60~+160 mesh. After passing through conventional physical beneficiation processes such as magnetic separation and flotation, the quartz concentrate was dried. (2) Prepare leaching solution A (containing 2 mol / L hydrofluoric acid + 2 mol / L hydrochloric acid + 2 mol / L nitric acid), weigh 30g of the above quartz concentrate and place it in a reaction vessel, add leaching solution A, the liquid-solid ratio is 3mL:1g, carry out constant temperature leaching, the leaching temperature is 80℃, stir and react for 6 hours, wash thoroughly with ultrapure water, filter and dry to obtain primary quartz sand; (3) Prepare leachate B (1 mol / L sodium hydroxide solution), place primary quartz sand in a reaction vessel, add leachate B, control the liquid-solid ratio to 5 mL: 1 g, perform conventional alkaline leaching pretreatment at 90 °C for 60 minutes, after alkaline leaching, wash thoroughly with ultrapure water, filter and dry to obtain intermediate quartz sand. (4) The obtained intermediate-grade quartz sand was placed in another reaction tank, and leaching solution C (5 mol / L phosphoric acid solution) was added to remove impurities by phosphoric acid leaching. The liquid-solid ratio was controlled at 5 mL:1 g, the temperature was 90 °C, and the leaching time was 120 minutes. After the reaction was completed, the sand was thoroughly washed with ultrapure water and dried to obtain high-purity quartz sand with a final purity of 99.985%.

[0045] Comparative Example 4 (Phosphoric acid replaced with hydrochloric acid) The difference between this comparative example and Example 1 is that in step (4), the 5 mol / L phosphoric acid solution is replaced with a 5 mol / L hydrochloric acid solution, while the other steps and parameters are the same as in Example 1.

[0046] The final product is high-purity quartz sand with a purity of 99.988%.

[0047] Comparative Example 5 (calcination and water quenching) A method for preparing high-purity quartz, the specific steps of which are as follows: (1) The raw quartz ore from a vein in Hubei Province was subjected to coarse crushing, wet screening for desliming, drying, fine crushing, ball milling and screening to obtain a grinding sample with a particle size range of -60~+160 mesh. After passing through conventional physical beneficiation processes such as magnetic separation and flotation, the quartz concentrate was dried. (2) The quartz concentrate was roasted in a tube furnace for 1 hour, and then quickly poured into ultrapure water for water quenching and cooling. A certain amount of the above quartz sand was weighed and placed in a reaction vessel. The prepared leaching solution A (2 mol / L hydrofluoric acid + 2 mol / L hydrochloric acid + 2 mol / L nitric acid) was added for constant temperature leaching. The liquid-solid ratio was 3 mL: 1 g, the leaching temperature was 80 °C, and the leaching was stirred for 8 hours. The quartz sand was thoroughly washed with ultrapure water, filtered, and dried to obtain high-purity quartz sand with a final purity of 99.988%.

[0048] Comparative Example 6 (calcination and water quenching) A method for preparing high-purity quartz, the specific steps of which are as follows: (1) The raw quartzite ore from Gansu was subjected to coarse crushing, wet screening, desliming, drying, fine crushing, ball milling and screening to obtain a grinding sample with a particle size range of -60~+160 mesh. After passing through conventional physical beneficiation processes such as magnetic separation and flotation, the quartz concentrate was dried. (2) The quartz concentrate was roasted in a tube furnace for 1 hour, and then quickly poured into ultrapure water for water quenching and cooling. A certain amount of the above quartz sand was weighed and placed in a reaction vessel. The prepared leaching solution A (2 mol / L hydrofluoric acid + 2 mol / L hydrochloric acid + 2 mol / L nitric acid) was added for constant temperature leaching. The liquid-solid ratio was 3 mL: 1 g, the leaching temperature was 80 °C, and the leaching was stirred for 6 hours. The quartz sand was thoroughly washed with ultrapure water, filtered, and dried to obtain high-purity quartz sand with a final purity of 99.982%.

[0049] The purity and impurity content of the quartz sand obtained in each embodiment and comparative example were tested. The impurity content was determined by ICP-OES. The main impurity contents of the raw quartz ore from a vein in Hubei Province and a raw quartzite ore from a quartzite mine in Gansu Province used in the embodiments and comparative examples are as follows: The main impurity content of a certain vein of quartz ore in Hubei Province is: Fe 52.77 μg·g -1 Al 307.22 μg·g -1 Na 13.55 μg·g -1 K 83.39 μg·g -1 The SiO2 content in the raw quartz ore is approximately 99.94%.

[0050] The main impurity content of a certain quartzite ore in Gansu Province is: Fe 505.16 μg·g -1 Al 780.46 μg·g -1 Na 72.83 μg·g -1K 227.34 μg·g -1 The SiO2 content in the raw quartz ore is approximately 99.80%.

[0051] The purity and impurity content of the quartz sand obtained in each embodiment and comparative example are shown in Table 1 below.

[0052] Table 1

[0053] Table 1 shows that the step-by-step leaching process proposed in this invention successfully increases the SiO2 purity of quartz sand to over 99.99% without high-temperature roasting, and significantly reduces the total impurity content. The total impurity content in Comparative Example 2 is higher than in Example 1, indicating that the ultrasonic alkaline leaching step effectively opens crack channels, creating conditions for subsequent deep impurity removal via ultrasonic leaching with phosphoric acid. The impurity content in Comparative Example 3 is higher than in Example 1, proving that the ultrasonic cavitation effect can significantly improve mass transfer efficiency. The total impurity content in Comparative Example 4 is higher than in Example 1, indicating that phosphoric acid, through its complexing ability, can more effectively remove impurities such as Al and Fe, and that phosphoric acid has low volatility and weak corrosivity, making it safer and more environmentally friendly. The purity of Comparative Example 5 is comparable to that of Example 1, but this invention completely eliminates the energy-intensive roasting step, conforming to the trend of green manufacturing, and has an even lower total impurity content. The comparison between Example 3 and Comparative Example 6 shows that the process of this invention has good applicability to different types of quartz ore (vein quartz, quartzite), and performs better in purifying low-purity quartzite ore.

[0054] Figure 2 (a) is a SEM image of the raw quartz ore in Example 3. Figure 2 (c) is a SEM image of the high-purity quartz sand in Example 3. Figure 2 (b) is a SEM image of the high-purity quartz sand in Comparative Example 3. It can be seen that the surface of the raw quartz ore is smooth, while the surface of the high-purity quartz sand has obvious cracks. The formation of these cracks is the result of the ultrasonic alkaline leaching pretreatment in step (3), which provides an effective channel for the subsequent penetration of phosphoric acid solution and the removal of impurities. In contrast, the surface of the quartz sand in Comparative Example 3 that has not undergone ultrasonic alkaline leaching pretreatment is more intact and it is difficult to form a similar mass transfer path.

[0055] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. A method for preparing high-purity quartz without calcination using ultrasound-assisted methods, characterized in that, Includes the following steps: S1. The raw quartz ore is crushed, ground, and classified to obtain a ground sample, which is then subjected to magnetic separation and flotation to obtain quartz concentrate. S2. The quartz concentrate is added to a mixed acid solution for constant temperature leaching, and after washing and drying, primary quartz sand is obtained. S3. The primary quartz sand is added to an alkaline solution and subjected to room temperature ultrasonic alkaline leaching. After washing and drying, intermediate quartz sand is obtained. S4. The intermediate-grade quartz sand is added to a phosphoric acid solution for ultrasonic acid leaching at room temperature. After washing and drying, high-purity quartz sand is obtained.

2. The method for preparing high-purity quartz without calcination using ultrasound-assisted methods according to claim 1, characterized in that, In step S1, the particle size of the grinding sample is -60 mesh to +160 mesh.

3. The method for preparing high-purity quartz without calcination using ultrasound-assisted methods according to claim 1, characterized in that, In step S2, the mixed acid solution includes 1~4 mol / L hydrofluoric acid, 1~4 mol / L hydrochloric acid and 1~4 mol / L nitric acid.

4. The method for preparing high-purity quartz without calcination using ultrasound-assisted methods according to claim 1, characterized in that, In step S2, the liquid-to-solid ratio of the quartz concentrate to the mixed acid solution is (2~5) mL:1g.

5. The method for preparing high-purity quartz without calcination using ultrasound-assisted methods according to claim 1, characterized in that, In step S2, the temperature of the constant temperature leaching is 60℃~100℃, and the leaching time is 5~10h.

6. The method for preparing high-purity quartz without calcination using ultrasound-assisted methods according to claim 1, characterized in that, In step S3, the concentration of alkali in the alkaline solution is 0.2~1.5 mol / L.

7. The method for preparing high-purity quartz without calcination using ultrasound-assisted methods according to claim 1, characterized in that, In step S3, the liquid-solid ratio of the primary quartz sand to the alkaline solution is (2~6) mL:1g.

8. The method for preparing high-purity quartz without calcination using ultrasound-assisted methods according to claim 1, characterized in that, In step S3, the ultrasonic alkaline immersion time is 30~120min, and the ultrasonic alkaline immersion power is 100~500W.

9. The method for preparing high-purity quartz without calcination using ultrasound-assisted methods according to claim 1, characterized in that, In step S4, the concentration of the phosphoric acid solution is 1~8 mol / L; the liquid-solid ratio of the medium-grade quartz sand to the phosphoric acid solution is (2~7) mL:1g.

10. The method for preparing high-purity quartz without calcination using ultrasound-assisted methods according to claim 1, characterized in that, In step S4, the ultrasonic acid leaching time is 30~180min, and the ultrasonic acid leaching power is 100~500W.

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