A method for preparing high-purity quartz sand by using North Sea group quartz

Abstract

The application discloses a method for preparing high-purity quartz sand by using Beihai quartz. The method comprises the following steps: S1, crushing; S2, acid washing; S3, grinding; S4, gravity separation; S5, magnetic separation; S6, primary flotation; S7, primary high-pressure acid leaching; S8, secondary flotation; S9, calcination and water quenching; S10, alkali leaching; and S11, secondary high-pressure acid leaching. The method removes the impurity-containing quartz with changed surface properties after the primary high-pressure acid leaching through secondary flotation, and further removes the impurities in the quartz sand through secondary high-pressure acid leaching by using the cracks generated on the surface of the quartz sand after the calcination and water quenching. Meanwhile, the method also performs alkali leaching before the secondary high-pressure acid leaching, so that the activity of the quartz sand is improved, and the effect of the secondary high-pressure acid leaching is strengthened. The Beihai quartz is used as the high-purity quartz raw material, the prepared quartz concentrate has high purity, the used processes are all common processes in actual production, and the method has great practical significance.

Description

Technical Field

[0001] This invention belongs to the field of deep processing of quartz sand, and in particular relates to a method for preparing high-purity quartz sand using Beihai Formation quartz. Background Technology

[0002] High-purity quartz is widely used in electronics, aerospace, fiber optic communication and other fields. In recent years, with the rise of the photovoltaic industry, the manufacturing of monocrystalline silicon in photovoltaic modules requires high-purity quartz crucibles as carriers. Since quartz crucibles are consumables in production, the demand for high-purity quartz at home and abroad has further increased.

[0003] Existing processes for processing high-purity quartz commonly employ traditional physical beneficiation methods such as gravity separation, magnetic separation, and flotation for preliminary purification. More importantly, they utilize chemical beneficiation methods for deep purification, including acid leaching, alkali leaching, and roasting. Quartz ores from different mineral origins exhibit significant differences in properties, including the types and distribution characteristics of gangue minerals, the size of quartz crystals, and the characteristics of gas-liquid inclusions. Therefore, different processing flows are suitable for different types of quartz ores.

[0004] Beihai boasts abundant and diverse quartz resources, with some quartz deposits possessing significant processing potential. However, challenges arise due to poor crystal shape, complex gangue mineral distribution, and a wide grain size range. Specifically, the quartz crystals in the Beihai Formation are predominantly anhedral and contain gangue minerals such as mica and feldspar. Mica exists between or within quartz grains, with a large grain size range from a few micrometers to two hundred micrometers, making purification quite difficult. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and propose a method for preparing high-purity quartz sand using Beihai Formation quartz, thereby solving the technical problem of the difficulty in preparing high-purity quartz using Beihai Formation quartz ore as raw material in the prior art.

[0006] This invention provides a method for preparing high-purity quartz sand using Beihai Formation quartz, comprising the following steps:

[0007] S1. Crushing: Crushing raw quartz ore to obtain quartz sand;

[0008] S2. Pickling: Immerse the crushed quartz sand in hydrochloric acid solution;

[0009] S3. Grinding: After washing the acid-washed quartz sand to neutral, grind it.

[0010] S4. Gravity separation: Gravity separation of the ground quartz sand;

[0011] S5. Magnetic separation: Magnetic separation is performed on the gravity-separated quartz sand;

[0012] S6. Primary flotation: The magnetically separated quartz sand is subjected to flotation to obtain primary flotation quartz concentrate;

[0013] S7. First high-pressure acid leaching: The first-flotation quartz concentrate is placed in an acid solution for a first high-pressure acid leaching, and then washed until neutral;

[0014] S8. Secondary flotation: The primary flotation quartz concentrate after the primary high-pressure acid leaching is subjected to secondary flotation to obtain secondary flotation quartz concentrate.

[0015] S9. Calcination and water quenching: The secondary flotation quartz concentrate is calcined and then placed in water for water quenching.

[0016] S10, Alkali leaching: The calcined and water-quenched secondary flotation quartz concentrate is placed in an alkaline solution for alkali leaching, and then washed until neutral.

[0017] S11. Secondary high-pressure acid leaching: The quartz concentrate after alkali leaching is placed in an acid solution for secondary high-pressure acid leaching, and then washed until neutral to obtain high-purity quartz sand.

[0018] Compared with the prior art, the beneficial effects of the present invention include:

[0019] This invention adds a second high-pressure acid leaching step to the first high-pressure acid leaching step, and a second flotation step to the first flotation step. The purpose of the second flotation step is to remove impurities in the quartz sand whose surface properties have changed after the first high-pressure acid leaching. The second high-pressure acid leaching can further remove impurities inside the quartz sand by utilizing the cracks created on the surface of the quartz sand after calcination and water quenching. At the same time, this invention also performs alkaline leaching before the second high-pressure acid leaching step to improve the activity of the quartz sand and enhance the effect of the second high-pressure acid leaching step. This invention uses Beihai quartz mine as high-purity quartz raw material, and the quartz concentrate prepared has a high purity. The processes used are all commonly used processes in actual production, which has great practical significance. Attached Figure Description

[0020] Figure 1 This is a process flow diagram of one embodiment of the method for preparing high-purity quartz sand using Beihai Formation quartz according to the present invention;

[0021] Figure 2 This is a process flow diagram of another embodiment of the method for preparing high-purity quartz sand using Beihai Formation quartz according to the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0023] Please see Figure 1This invention provides a method for preparing high-purity quartz sand using Beihai Formation quartz, comprising the following steps:

[0024] S1. Crushing: Crushing raw quartz ore to obtain quartz sand;

[0025] S2. Pickling: The crushed quartz sand is soaked in hydrochloric acid solution to remove iron-containing impurities from the surface of the quartz sand.

[0026] S3. Grinding: After washing the acid-washed quartz sand to neutral, grind it.

[0027] S4. Gravity separation: The ground quartz sand is subjected to gravity separation to separate quartz from heavy minerals in order to remove heavy minerals; among which, heavy minerals include zircon, rutile, etc.

[0028] S5. Magnetic separation: The gravity-separated quartz sand is subjected to magnetic separation to remove iron-containing minerals;

[0029] S6. Primary flotation: The magnetically separated quartz sand is subjected to flotation to obtain primary flotation quartz concentrate;

[0030] S7. First high-pressure acid leaching: The first flotation quartz concentrate is placed in an acid solution for a first high-pressure acid leaching to further remove iron-containing minerals and feldspar that could not be removed by flotation, and then washed until neutral.

[0031] S8. Secondary flotation: The primary flotation quartz concentrate after the primary high-pressure acid leaching is subjected to secondary flotation to remove quartz with surface defects, thus obtaining secondary flotation quartz concentrate.

[0032] S9. Calcination and water quenching: The secondary flotation quartz concentrate is calcined and then placed in water for water quenching, which creates cracks on the surface of the quartz, which is beneficial for subsequent secondary high-pressure acid leaching.

[0033] S10, Alkali leaching: The calcined and water-quenched secondary flotation quartz concentrate is placed in an alkaline solution for alkali leaching to improve the surface activity of the quartz, and then washed until neutral.

[0034] S11, Secondary High-Pressure Acid Leaching: The quartz concentrate after alkali leaching is placed in an acid solution for secondary high-pressure acid leaching. The acid enters the interior of the quartz sand through the cracks generated by calcination and water quenching, removing the impurities present inside. Then it is washed until neutral to obtain high-purity quartz sand.

[0035] It should be noted that in this invention, a second high-pressure acid leaching is added on top of the first high-pressure acid leaching, and a second flotation is added on top of the first flotation. The purpose of the second flotation is to remove impurity-containing quartz whose surface properties have changed after the first high-pressure acid leaching. The second high-pressure acid leaching can further remove impurities inside the quartz sand by utilizing the cracks created on the surface of the quartz sand after calcination and water quenching. Simultaneously, in the method of this invention, an alkaline leaching is added between calcination and water quenching and the second high-pressure acid leaching. Calcination and water quenching create cracks on the surface of the quartz sand, opening channels, and then the alkaline solution is used to disrupt the quartz crystal lattice structure, causing impurities within the lattice to become easily removable free states. This, combined with the second high-pressure acid leaching, removes the exposed lattice impurities, achieving the purpose of removing some impurity elements, while simultaneously increasing the activity of the quartz sand and enhancing the effect of the second high-pressure acid leaching. In addition, unlike the prior art, the method of the present invention does not involve calcination and water quenching before grinding. The inventors found in experiments that after calcination and water quenching, the quartz sand will produce many cracks, which is beneficial to the grinding process, but at the same time it also increases the risk of impurities entering in the subsequent process, thus leading to contamination. The present invention, by not performing calcination and water quenching before grinding, is more conducive to improving the purity of the concentrate.

[0036] In this invention, the quartz ore comes from the Beihai region, and the SiO2 content in the quartz ore is 99% to 99.95% by mass. The quartz of the Beihai Formation has the following main characteristics: the main mineral is quartz, mainly with anhedral granular structure, with a grain size of 0.1 to 1 cm. There are many gangue minerals in the quartz grains or between the quartz grains, and they vary in size, mainly mica, with a grain size of 5 to 200 μm.

[0037] In some embodiments, during the crushing step, the quartz ore is crushed to a particle size of less than 5 mm.

[0038] In some embodiments, during the pickling step, the quartz sand is soaked in hydrochloric acid solution for 12–24 hours.

[0039] In some specific embodiments, during the pickling step, the mass fraction of the hydrochloric acid solution is 5-10%, and the solid-liquid ratio of the pickling is 1g:(1-2)mL.

[0040] In some embodiments, during the grinding step, the quartz is ground to a mesh size of 40–140 mesh (i.e., 0.105–0.45 mm). If the particle size is too coarse, the quartz cannot achieve monomer liberation; if the particle size is too fine, its application will be limited.

[0041] In some specific embodiments, a ball mill is used for closed-circuit grinding in the grinding step.

[0042] In some embodiments, the reselection device is a shaking table during the reselection step.

[0043] In some embodiments, the magnetic separation intensity is 1 to 1.5 T during the magnetic separation step.

[0044] In some specific embodiments, a high-gradient magnetic separator is used for magnetic separation in the magnetic separation step.

[0045] In some specific embodiments, the magnetic separation process involves three magnetic separation stages, i.e., three magnetic separations.

[0046] In some embodiments, a single flotation step includes:

[0047] S61, Three-stage floating mica: The magnetically separated quartz sand is subjected to three-stage floating mica flotation; the collector used in the flotation process is dodecylamine, and the flotation pulp concentration is 30-40%; the reagent dosage for the three stages of flotation is as follows, based on m (reagent) / m (quartz sand): Stage 1, 100-200 g / t, Stage 2, 50-100 g / t, Stage 3, 40-60 g / t; the pH is controlled at 2-3;

[0048] S62. Three-stage pumice: The quartz concentrate after three-stage pumice (mica flotation) is subjected to three-stage pumice flotation. The collectors used in the flotation process are sodium petroleum sulfonate and dodecylamine, and the flotation pulp concentration is 30-40%. Based on m (reagent) / m (quartz sand), the reagent dosages for the three stages of flotation are as follows: Stage 1: Sodium petroleum sulfonate 500-700 g / t, dodecylamine 200-400 g / t; Stage 2: Sodium petroleum sulfonate 200-400 g / t, dodecylamine 100-200 g / t; Stage 3: Sodium petroleum sulfonate 200-400 g / t, dodecylamine 100-200 g / t; pH is controlled at 1.5-2.

[0049] S63, First-stage flotation of iron-bearing minerals: The quartz concentrate after the three-stage flotation of feldspar is subjected to first-stage flotation of iron-bearing minerals; wherein, the collector used in the flotation process is sodium petroleum sulfonate, the flotation pulp concentration is 30-40%; the reagent dosage is 800-1200 g / t based on m (reagent) / m (quartz sand), and the pH is controlled at 2-3.

[0050] The present invention can remove impurity minerals, such as mica, feldspar and iron-containing minerals, through the above-mentioned seven-stage flotation (i.e., a total of seven stages of flotation in steps S61 to S63).

[0051] In some specific embodiments, the steps of forming three segments of mica include:

[0052] S611. Quartz sand is added to the flotation machine, and dodecylamine is used as the collector. The pH is controlled at 2-3 to carry out a first-stage flotation to remove mica and obtain flotation concentrate and flotation tailings.

[0053] S612. Add flotation concentrate one to the flotation machine, use dodecylamine as the collector, control the pH to 2-3 for two-stage flotation, continue to remove mica, and obtain flotation concentrate two and flotation tailings two.

[0054] S613. Add flotation concentrate II to the flotation machine, use dodecylamine as the collector, control the pH to 2-3 and carry out three-stage flotation to continue removing mica, and obtain flotation concentrate III and flotation tailings III.

[0055] In some specific embodiments, the step of using three sections of pumice includes:

[0056] S621. Add flotation concentrate three to the flotation machine, use sodium petroleum sulfonate and dodecylamine as collectors, control the pH to 1.5-2 to carry out a first stage of flotation to remove feldspar, and obtain flotation concentrate four and flotation tailings four.

[0057] S622. Add flotation concentrate four to the flotation machine, use sodium petroleum sulfonate and dodecylamine as collectors, control the pH to 1.5-2 for two-stage flotation, continue to remove feldspar, and obtain flotation concentrate five and flotation tailings five.

[0058] S623. Add flotation concentrate five to the flotation machine, use sodium petroleum sulfonate and dodecylamine as collectors, control the pH to 1.5-2 for three-stage flotation, continue to remove feldspar, and obtain flotation concentrate six and flotation tailings six.

[0059] In some specific embodiments, the step of floating iron-bearing minerals includes:

[0060] Flotation concentrate 6 is added to the flotation machine, sodium petroleum sulfonate is used as the collector, and the pH is controlled at 2-3 to carry out a first-stage flotation to remove iron-containing minerals, so as to obtain flotation concentrate 7 (i.e., primary flotation quartz concentrate) and flotation tailings 7.

[0061] In some embodiments, the acid solution used in the high-pressure acid leaching step includes at least one of hydrochloric acid solution, nitric acid solution, and hydrofluoric acid solution. Further, the concentration of hydrochloric acid in the acid solution is 0–4 mol / L, the concentration of nitric acid is 0–2 mol / L, and the concentration of hydrofluoric acid is 0–5 mol / L.

[0062] In some embodiments, during a single high-pressure acid leaching step, the ratio of flotation quartz concentrate to acid is 1 g: (2-10) mL.

[0063] In some embodiments, during a single high-pressure acid leaching step, the acid leaching temperature is 90–220°C, and the acid leaching time is 3–6 hours.

[0064] In some specific embodiments, the acid leaching step is carried out in a reaction vessel during a single high-pressure acid leaching process.

[0065] In some embodiments, the collectors used in the secondary flotation step are sodium petroleum sulfonate and dodecylamine, the pulp concentration is 30-40%, and there are two flotation stages. Based on m (reagent) / m (quartz sand), the first stage uses 300-500 g / t of sodium petroleum sulfonate and 100-300 g / t of dodecylamine, and the second stage uses 100-300 g / t of sodium petroleum sulfonate and 80-120 g / t of dodecylamine, with the pH controlled at 1.5-2.

[0066] In some specific embodiments, the secondary flotation step includes:

[0067] The quartz concentrate after one high-pressure acid leaching is added to the flotation machine. The pulp concentration is 30-40%. The flotation reagents are 300-500 g / t of sodium petroleum sulfonate and 100-300 g / t of dodecylamine, calculated by m (reagent) / m (quartz sand). The pH is controlled at 1.5-2. After one stage of flotation to remove impurities, flotation concentrate and flotation tailings are obtained.

[0068] Add flotation concentrate 8 to the flotation machine. The pulp concentration is 30-40%. The flotation reagents are 100-300 g / t of sodium petroleum sulfonate and 80-120 g / t of dodecylamine, calculated by m (reagent) / m (quartz sand). Control the pH to 1.5-2. After two-stage flotation to remove impurities, flotation concentrate 9 (i.e., secondary flotation quartz concentrate) and flotation tailings 9 are produced.

[0069] In some embodiments, during the calcination and water quenching step, the calcination temperature is 900–1100°C and the calcination time is 1–3 hours.

[0070] In some embodiments, during the alkaline leaching step, the alkaline solution is at least one of sodium hydroxide solution and potassium hydroxide solution.

[0071] In some specific embodiments, during the alkali leaching step, the concentration of alkali is 0.3 to 0.7 mol / L, and the solid-liquid ratio is 1 g: (2 to 4) mL.

[0072] In some embodiments, during the alkali immersion step, the alkali immersion temperature is 40–80°C, and the alkali immersion time is 3–8 hours.

[0073] In some embodiments, the acid solution used in the secondary high-pressure acid leaching step includes at least one of hydrochloric acid solution, nitric acid solution, and hydrofluoric acid solution. Further, in the acid solution used, the concentration of hydrochloric acid is 0–4 mol / L, the concentration of nitric acid is 0–2 mol / L, and the concentration of hydrofluoric acid is 0–5 mol / L.

[0074] In some embodiments, in the secondary high-pressure acid leaching step, the ratio of the amount of secondary flotation quartz concentrate treated with alkali to the amount of acid is 1g:(2-10)mL.

[0075] In some embodiments, during the secondary high-pressure acid leaching step, the acid leaching temperature is 90–220°C, and the acid leaching time is 3–6 hours.

[0076] In some specific embodiments, the secondary high-pressure acid leaching step is carried out in a reaction vessel.

[0077] Please see Figure 2 In some embodiments, the above-described method for preparing high-purity quartz sand using Beihai Formation quartz further includes the following steps:

[0078] S12, Chlorination Roasting: The quartz concentrate after secondary high-pressure acid leaching is subjected to chlorination roasting to convert impurities such as sodium and lithium into gases and carry them out, thereby obtaining high-purity quartz sand.

[0079] In some specific embodiments, during the chlorination roasting step, the chlorination roasting temperature is 800–1100°C, the chlorination roasting time is 1–3 hours, and the chlorination roasting atmosphere is hydrogen chloride.

[0080] In some specific embodiments, the chlorination roasting step is carried out in a tubular muffle furnace.

[0081] Example 1

[0082] This embodiment provides a method for preparing high-purity quartz sand using Beihai Formation quartz, including the following steps:

[0083] (1) Crushing: The raw quartz ore is crushed to a grinding feed particle size of less than 5 mm to obtain quartz sand; the raw quartz ore comes from the Beihai area and the mass content of SiO2 in the raw quartz ore is 99% to 99.95%;

[0084] (2) Acid washing: The quartz sand was soaked in a 10% hydrochloric acid solution for 12 hours with a solid-liquid ratio of 1g:1mL.

[0085] (3) Grinding: After the acid-washed quartz sand is washed to neutral, it is ground in a closed-circuit ball mill to 80-140 mesh.

[0086] (4) Gravity separation: The ground quartz sand is subjected to gravity separation. The gravity separation equipment is a shaking table to separate quartz from heavy minerals;

[0087] (5) Magnetic separation: The gravity-separated quartz sand is subjected to magnetic separation using a high-gradient magnetic separator with three magnetic separation stages and an electric field strength of 1.4T in each stage to remove magnetic minerals;

[0088] (6) Primary flotation: The magnetically separated quartz sand is subjected to flotation to obtain primary flotation quartz concentrate, specifically including:

[0089] (61) Three-stage floating mica: The magnetically separated quartz sand is subjected to three-stage floating mica; wherein, the pulp concentration is 35%, the collector used in the flotation process is dodecylamine, and the reagent dosage for the three stages of flotation is 150g / t, 70g / t and 50g / t respectively, based on m(reagent) / m(quartz sand), and the pH is controlled at 2.5;

[0090] (62) Three-stage pumice flotation: Three-stage pumice flotation is carried out after three-stage pumice flotation; the pulp concentration is 35%, and the collectors used in the flotation process are sodium petroleum sulfonate and dodecylamine. The reagent dosages for the three stages of flotation are as follows, calculated as m (reagent) / m (quartz sand): Stage 1: 600 g / t sodium petroleum sulfonate, 300 g / t dodecylamine; Stage 2: 300 g / t sodium petroleum sulfonate, 150 g / t dodecylamine; Stage 3: 300 g / t sodium petroleum sulfonate, 150 g / t dodecylamine; pH is controlled at 1.8.

[0091] (63) First stage of iron mineral flotation: After three stages of feldspar flotation, a first stage of iron mineral flotation is carried out; wherein, the pulp concentration is 35%, the collector used in the flotation process is sodium petroleum sulfonate, the reagent dosage is 1000g / t based on m(reagent) / m(quartz sand), and the pH is controlled at 2.5.

[0092] (7) First high-pressure acid leaching: The first flotation quartz concentrate is placed in acid solution and then placed in a reaction vessel and reacted at 220℃ for 5 hours, and washed until neutral; wherein, the mass-volume ratio of the first flotation quartz concentrate to the acid solution is 10g:50mL, and the acid solution is a mixture of hydrochloric acid solution, nitric acid solution and hydrofluoric acid solution, with the concentration of hydrochloric acid in the acid solution being 3mol / L, the concentration of nitric acid being 1mol / L and the concentration of hydrofluoric acid being 1mol / L;

[0093] (8) Secondary flotation: The acid-treated primary flotation quartz concentrate is subjected to secondary flotation to obtain secondary flotation quartz concentrate; wherein, the pulp concentration is 35%, the number of flotation stages is two, and the collectors used in the secondary flotation process are sodium petroleum sulfonate and dodecylamine. The reagent dosages for the two stages of flotation are as follows, calculated as m (reagent) / m (quartz sand): First stage, sodium petroleum sulfonate 400g / t, dodecylamine 200g / t; Second stage, sodium petroleum sulfonate 200g / t, dodecylamine 100g / t, and the pH is controlled at 1.8;

[0094] (9) Calcination and water quenching: After calcining the secondary flotation quartz concentrate at 1000℃ for 2 hours, it is placed in water for water quenching;

[0095] (10) Alkali leaching: The calcined and water-quenched quartz concentrate was placed in a 0.5 mol / L KOH solution and reacted at 40°C for 4 h, and then washed until neutral; wherein the mass-volume ratio of the calcined and water-quenched quartz concentrate to the KOH solution was 20 g: 40 mL.

[0096] (11) Secondary high-pressure acid leaching: The quartz concentrate after alkali leaching is placed in acid solution and then placed in a reaction vessel. It is reacted at 220℃ for 5 hours, washed until neutral, and dried to obtain high-purity quartz sand. The mass-volume ratio of the alkali-leached quartz concentrate to the acid solution is 10g:50mL. The acid solution is a mixture of hydrochloric acid solution, nitric acid solution, and hydrofluoric acid solution. The concentration of hydrochloric acid in the acid solution is 3mol / L, the concentration of nitric acid is 1mol / L, and the concentration of hydrofluoric acid is 1mol / L.

[0097] Example 2

[0098] This embodiment provides a method for preparing high-purity quartz sand using Beihai Formation quartz, including the following steps:

[0099] (1) Crushing: The raw quartz ore is crushed to a grinding feed particle size of less than 5 mm to obtain quartz sand; the raw quartz ore comes from the Beihai area and the mass content of SiO2 in the raw quartz ore is 99% to 99.95%;

[0100] (2) Acid washing: The quartz sand was soaked in a 10% hydrochloric acid solution for 12 hours with a solid-liquid ratio of 1g:1mL.

[0101] (3) Grinding: After the acid-washed quartz sand is washed to neutral, it is ground in a closed-circuit ball mill to 80-140 mesh.

[0102] (4) Gravity separation: The ground quartz sand is subjected to gravity separation. The gravity separation equipment is a shaking table to separate quartz from heavy minerals;

[0103] (5) Magnetic separation: The gravity-separated quartz sand is subjected to magnetic separation using a high-gradient magnetic separator with three magnetic separation stages and an electric field strength of 1.4T in each stage to remove magnetic minerals;

[0104] (6) Primary flotation: The magnetically separated quartz sand is subjected to flotation to obtain primary flotation quartz concentrate, specifically including:

[0105] (61) Three-stage floating mica: The magnetically separated quartz sand is subjected to three-stage floating mica; wherein, the pulp concentration is 35%, the collector used in the flotation process is dodecylamine, and the reagent dosage for the three stages of flotation is 150g / t, 70g / t and 50g / t respectively, based on m(reagent) / m(quartz sand), and the pH is controlled at 2.5;

[0106] (62) Three-stage pumice flotation: Three-stage pumice flotation is carried out after three-stage pumice flotation; the pulp concentration is 35%, and the collectors used in the flotation process are sodium petroleum sulfonate and dodecylamine. The reagent dosages for the three stages of flotation are as follows, calculated as m (reagent) / m (quartz sand): Stage 1: 600 g / t sodium petroleum sulfonate, 300 g / t dodecylamine; Stage 2: 300 g / t sodium petroleum sulfonate, 150 g / t dodecylamine; Stage 3: 300 g / t sodium petroleum sulfonate, 150 g / t dodecylamine; pH is controlled at 1.8.

[0107] (63) First stage of iron mineral flotation: After three stages of feldspar flotation, a first stage of iron mineral flotation is carried out; wherein, the pulp concentration is 35%, the collector used in the flotation process is sodium petroleum sulfonate, the reagent dosage is 1000g / t based on m(reagent) / m(quartz sand), and the pH is controlled at 2.5.

[0108] (7) First high-pressure acid leaching: The first flotation quartz concentrate is placed in acid solution and then placed in a reaction vessel and reacted at 90°C for 5 hours, and washed until neutral; wherein, the mass-volume ratio of the first flotation quartz concentrate to the acid solution is 10g:50mL, and the acid solution is a 5mol / L hydrofluoric acid solution.

[0109] (8) Secondary flotation: The acid-treated primary flotation quartz concentrate is subjected to secondary flotation to obtain secondary flotation quartz concentrate; wherein, the pulp concentration is 35%, the number of flotation stages is two, and the collectors used in the secondary flotation process are sodium petroleum sulfonate and dodecylamine. The reagent dosages for the two stages of flotation are as follows, calculated as m (reagent) / m (quartz sand): First stage, sodium petroleum sulfonate 400g / t, dodecylamine 200g / t; Second stage, sodium petroleum sulfonate 200g / t, dodecylamine 100g / t, and the pH is controlled at 1.8;

[0110] (9) Calcination and water quenching: After calcining the secondary flotation quartz concentrate at 1000℃ for 2 hours, it is placed in water for water quenching;

[0111] (10) Alkali leaching: The calcined and water-quenched quartz concentrate was placed in a 0.5 mol / L KOH solution and reacted at 40°C for 4 h, and then washed until neutral; wherein the mass-volume ratio of the calcined and water-quenched quartz concentrate to the KOH solution was 20 g: 40 mL.

[0112] (11) Secondary high-pressure acid leaching: The quartz concentrate after alkali leaching is placed in acid solution and then placed in a reaction vessel. It is reacted at 90°C for 5 hours, washed until neutral, and dried to obtain high-purity quartz sand. The mass-volume ratio of the alkali-leached quartz concentrate to the acid solution is 10g:50mL, and the acid solution is a 5mol / L hydrofluoric acid solution.

[0113] Example 3

[0114] Compared with Example 1, the only difference is that the method for preparing high-purity quartz sand using Beihai Formation quartz provided in this example further includes the following steps:

[0115] (12) Chlorination roasting: 6g of quartz sand after two high-pressure acid leaching is spread on a quartz boat, placed in a tubular muffle furnace, hydrogen chloride gas is introduced, and roasted at 1000℃ for 2h. After the roasting is completed, high-purity quartz concentrate is obtained.

[0116] Comparative Example 1

[0117] The method for preparing high-purity quartz sand using Beihai Formation quartz provided in this comparative example differs from Example 1 only in the process flow, which is as follows: crushing-acid washing-grinding-gravity separation-magnetic separation-flotation-calcination and water quenching-high pressure acid leaching, specifically including the following steps:

[0118] (1) Crushing: The raw quartz ore is crushed to a grinding feed particle size of less than 5 mm to obtain quartz sand; the raw quartz ore comes from the Beihai area and the mass content of SiO2 in the raw quartz ore is 99% to 99.95%;

[0119] (2) Acid washing: The quartz sand was soaked in a 10% hydrochloric acid solution for 12 hours with a solid-liquid ratio of 1g:1mL.

[0120] (3) Grinding: After the acid-washed quartz sand is washed to neutral, it is ground in a closed-circuit ball mill to 80-140 mesh.

[0121] (4) Gravity separation: The ground quartz sand is subjected to gravity separation. The gravity separation equipment is a shaking table to separate quartz from heavy minerals;

[0122] (5) Magnetic separation: The gravity-separated quartz sand is subjected to magnetic separation using a high-gradient magnetic separator with three magnetic separation stages and an electric field strength of 1.4T in each stage to remove magnetic minerals;

[0123] (6) Flotation: The magnetically separated quartz sand is subjected to flotation to obtain flotation quartz concentrate, specifically including:

[0124] (61) Three-stage floating mica: The magnetically separated quartz sand is subjected to three-stage floating mica; wherein, the pulp concentration is 35%, the collector used in the flotation process is dodecylamine, and the reagent dosage for the three stages of flotation is 150g / t, 70g / t and 50g / t respectively, based on m(reagent) / m(quartz sand), and the pH is controlled at 2.5;

[0125] (62) Three-stage pumice flotation: Three-stage pumice flotation is carried out after three-stage pumice flotation; the pulp concentration is 35%, and the collectors used in the flotation process are sodium petroleum sulfonate and dodecylamine. The reagent dosages for the three stages of flotation are as follows, calculated as m (reagent) / m (quartz sand): Stage 1: 600 g / t sodium petroleum sulfonate, 300 g / t dodecylamine; Stage 2: 300 g / t sodium petroleum sulfonate, 150 g / t dodecylamine; Stage 3: 300 g / t sodium petroleum sulfonate, 150 g / t dodecylamine; pH is controlled at 1.8.

[0126] (63) First stage of iron mineral flotation: After three stages of feldspar flotation, a first stage of iron mineral flotation is carried out; wherein, the pulp concentration is 35%, the collector used in the flotation process is sodium petroleum sulfonate, the reagent dosage is 1000g / t based on m(reagent) / m(quartz sand), and the pH is controlled at 2.5.

[0127] (7) Calcination and water quenching: After acid leaching, the quartz concentrate is calcined at 1000℃ for 2 hours and then placed in water for water quenching;

[0128] (8) High-pressure acid leaching: The calcined and water-quenched quartz concentrate is placed in an acid solution and then placed in a reaction vessel. It is reacted at 220°C for 5 hours. After washing until neutral, it is dried to obtain high-purity quartz sand. The mass-volume ratio of the calcined and water-quenched quartz concentrate to the acid solution is 10g:50mL. The acid solution is a mixture of hydrochloric acid solution, nitric acid solution and hydrofluoric acid solution. The concentration of hydrochloric acid in the acid solution is 3mol / L, the concentration of nitric acid is 1mol / L and the concentration of hydrofluoric acid is 1mol / L.

[0129] Comparative Example 2

[0130] The method for preparing high-purity quartz sand using Beihai Formation quartz provided in this comparative example differs from Example 1 only in the process flow, which is as follows: crushing-acid washing-grinding-gravity separation-magnetic separation-flotation-first high-pressure acid leaching-calcination and water quenching-second high-pressure acid leaching, specifically including the following steps:

[0131] (1) Crushing: The raw quartz ore is crushed to a grinding feed particle size of less than 5 mm to obtain quartz sand; the raw quartz ore comes from the Beihai area and the mass content of SiO2 in the raw quartz ore is 99% to 99.95%;

[0132] (2) Acid washing: The quartz sand was soaked in a 10% hydrochloric acid solution for 12 hours with a solid-liquid ratio of 1g:1mL.

[0133] (3) Grinding: After the acid-washed quartz sand is washed to neutral, it is ground in a closed-circuit ball mill to 80-140 mesh.

[0134] (4) Gravity separation: The ground quartz sand is subjected to gravity separation. The gravity separation equipment is a shaking table to separate quartz from heavy minerals;

[0135] (5) Magnetic separation: The gravity-separated quartz sand is subjected to magnetic separation using a high-gradient magnetic separator with three magnetic separation stages and an electric field strength of 1.4T in each stage to remove magnetic minerals;

[0136] (6) Flotation: The magnetically separated quartz sand is subjected to flotation to obtain flotation quartz concentrate, specifically including:

[0137] (61) Three-stage floating mica: The magnetically separated quartz sand is subjected to three-stage floating mica; wherein, the pulp concentration is 35%, the collector used in the flotation process is dodecylamine, and the reagent dosage for the three stages of flotation is 150g / t, 70g / t and 50g / t respectively, based on m(reagent) / m(quartz sand), and the pH is controlled at 2.5;

[0138] (62) Three-stage pumice flotation: Three-stage pumice flotation is carried out after three-stage pumice flotation; the pulp concentration is 35%, and the collectors used in the flotation process are sodium petroleum sulfonate and dodecylamine. The reagent dosages for the three stages of flotation are as follows, calculated as m (reagent) / m (quartz sand): Stage 1: 600 g / t sodium petroleum sulfonate, 300 g / t dodecylamine; Stage 2: 300 g / t sodium petroleum sulfonate, 150 g / t dodecylamine; Stage 3: 300 g / t sodium petroleum sulfonate, 150 g / t dodecylamine; pH is controlled at 1.8.

[0139] (63) First stage of iron mineral flotation: After three stages of feldspar flotation, a first stage of iron mineral flotation is carried out; wherein, the pulp concentration is 35%, the collector used in the flotation process is sodium petroleum sulfonate, the reagent dosage is 1000g / t based on m(reagent) / m(quartz sand), and the pH is controlled at 2.5.

[0140] (7) One-time high-pressure acid leaching: The flotation quartz concentrate is placed in the acid solution and then placed in a reaction vessel. It is reacted at 220℃ for 5 hours and washed until neutral. The mass-volume ratio of the flotation quartz concentrate to the acid solution is 10g:50mL. The acid solution is a mixture of hydrochloric acid solution, nitric acid solution and hydrofluoric acid solution. The concentration of hydrochloric acid in the acid solution is 3mol / L, the concentration of nitric acid is 1mol / L and the concentration of hydrofluoric acid is 1mol / L.

[0141] (8) Calcination and water quenching: After acid leaching, the quartz concentrate is calcined at 1000℃ for 2 hours and then placed in water for water quenching;

[0142] (9) Secondary high-pressure acid leaching: The calcined and water-quenched quartz concentrate is placed in acid solution and then placed in a reaction vessel. It is reacted at 220℃ for 5 hours. After washing until neutral, it is dried to obtain high-purity quartz sand. The mass-volume ratio of the calcined and water-quenched quartz concentrate to the acid solution is 10g:50mL. The acid solution includes a mixture of hydrochloric acid solution, nitric acid solution and hydrofluoric acid solution. The concentration of hydrochloric acid in the acid solution is 3mol / L, the concentration of nitric acid is 1mol / L and the concentration of hydrofluoric acid is 1mol / L.

[0143] Comparative Example 3

[0144] The method for preparing high-purity quartz sand using Beihai Formation quartz provided in this comparative example differs from Example 1 only in the process flow, which is as follows: crushing-acid washing-grinding-gravity separation-magnetic separation-primary flotation-primary high-pressure acid leaching-secondary flotation-calcination and water quenching-secondary high-pressure acid leaching, specifically including the following steps:

[0145] (1) Crushing: The raw quartz ore is crushed to a grinding feed particle size of less than 5 mm to obtain quartz sand; the raw quartz ore comes from the Beihai area and the mass content of SiO2 in the raw quartz ore is 99% to 99.95%;

[0146] (2) Acid washing: The quartz sand was soaked in a 10% hydrochloric acid solution for 12 hours with a solid-liquid ratio of 1g:1mL.

[0147] (3) Grinding: After the acid-washed quartz sand is washed to neutral, it is ground in a closed-circuit ball mill to 80-140 mesh.

[0148] (4) Gravity separation: The ground quartz sand is subjected to gravity separation. The gravity separation equipment is a shaking table to separate quartz from heavy minerals;

[0149] (5) Magnetic separation: The gravity-separated quartz sand is subjected to magnetic separation using a high-gradient magnetic separator with three magnetic separation stages and an electric field strength of 1.4T in each stage to remove magnetic minerals;

[0150] (6) Primary flotation: The magnetically separated quartz sand is subjected to flotation to obtain flotation quartz concentrate, specifically including:

[0151] (61) Three-stage floating mica: The magnetically separated quartz sand is subjected to three-stage floating mica; wherein, the pulp concentration is 35%, the collector used in the flotation process is dodecylamine, and the reagent dosage for the three stages of flotation is 150g / t, 70g / t and 50g / t respectively, based on m(reagent) / m(quartz sand), and the pH is controlled at 2.5;

[0152] (62) Three-stage pumice flotation: Three-stage pumice flotation is carried out after three-stage pumice flotation; the pulp concentration is 35%, and the collectors used in the flotation process are sodium petroleum sulfonate and dodecylamine. The reagent dosages for the three stages of flotation are as follows, calculated as m (reagent) / m (quartz sand): Stage 1: 600 g / t sodium petroleum sulfonate, 300 g / t dodecylamine; Stage 2: 300 g / t sodium petroleum sulfonate, 150 g / t dodecylamine; Stage 3: 300 g / t sodium petroleum sulfonate, 150 g / t dodecylamine; pH is controlled at 1.8.

[0153] (63) First stage of iron mineral flotation: After three stages of feldspar flotation, a first stage of iron mineral flotation is carried out; wherein, the pulp concentration is 35%, the collector used in the flotation process is sodium petroleum sulfonate, the reagent dosage is 1000g / t based on m(reagent) / m(quartz sand), and the pH is controlled at 2.5.

[0154] (7) One-time high-pressure acid leaching: The flotation quartz concentrate is placed in the acid solution and then placed in a reaction vessel. It is reacted at 220℃ for 5 hours and washed until neutral. The mass-volume ratio of the flotation quartz concentrate to the acid solution is 10g:50mL. The acid solution is a mixture of hydrochloric acid solution, nitric acid solution and hydrofluoric acid solution. The concentration of hydrochloric acid in the acid solution is 3mol / L, the concentration of nitric acid is 1mol / L and the concentration of hydrofluoric acid is 1mol / L.

[0155] (8) Secondary flotation: The acid-treated primary flotation quartz concentrate is subjected to secondary flotation to obtain secondary flotation quartz concentrate; wherein, the pulp concentration is 35%, the number of flotation stages is two, and the collectors used in the secondary flotation process are sodium petroleum sulfonate and dodecylamine. The reagent dosages for the two stages of flotation are as follows, calculated as m (reagent) / m (quartz sand): First stage, sodium petroleum sulfonate 400g / t, dodecylamine 200g / t; Second stage, sodium petroleum sulfonate 200g / t, dodecylamine 100g / t, and the pH is controlled at 1.8;

[0156] (9) Calcination and water quenching: After calcining the secondary flotation quartz concentrate at 1000℃ for 2 hours, it is placed in water for water quenching;

[0157] (10) Secondary high-pressure acid leaching: The calcined and water-quenched quartz concentrate is placed in acid solution and then placed in a reaction vessel. It is reacted at 220℃ for 5 hours. After washing until neutral, it is dried to obtain high-purity quartz sand. The mass-volume ratio of the calcined and water-quenched quartz concentrate to the acid solution is 10g:50mL. The acid solution includes a mixture of hydrochloric acid solution, nitric acid solution and hydrofluoric acid solution. The concentration of hydrochloric acid in the acid solution is 3mol / L, the concentration of nitric acid is 1mol / L and the concentration of hydrofluoric acid is 1mol / L.

[0158] Comparative Example 4

[0159] The method for preparing high-purity quartz sand using Beihai Formation quartz provided in this comparative example differs from Example 1 only in the process flow, which is as follows: crushing-acid washing-first calcination and water quenching-grinding-gravity separation-magnetic separation-first flotation-first high-pressure acid leaching-second flotation-second calcination and water quenching-second high-pressure acid leaching, specifically including the following steps:

[0160] (1) Crushing: The raw quartz ore is crushed to a grinding feed particle size of less than 5 mm to obtain quartz sand; the raw quartz ore comes from the Beihai area and the mass content of SiO2 in the raw quartz ore is 99% to 99.95%;

[0161] (2) Acid washing: The quartz sand was soaked in a 10% hydrochloric acid solution for 12 hours with a solid-liquid ratio of 1g:1mL.

[0162] (3) One-time calcination and water quenching: After the acid-washed quartz sand is calcined at 1000℃ for 2 hours, it is placed in water for water quenching;

[0163] (4) Grinding: The calcined and water-quenched quartz sand is ground in a closed-circuit ball mill to 80-140 mesh.

[0164] (5) Gravity separation: The ground quartz sand is subjected to gravity separation. The gravity separation equipment is a shaking table to separate quartz from heavy minerals;

[0165] (6) Magnetic separation: The gravity-separated quartz sand is subjected to magnetic separation using a high-gradient magnetic separator with three magnetic separation stages and an electric field strength of 1.4T in each stage to remove magnetic minerals;

[0166] (7) Primary flotation: The magnetically separated quartz sand is subjected to flotation to obtain primary flotation quartz concentrate, specifically including:

[0167] (71) Three-stage floating mica: The magnetically separated quartz sand is subjected to three-stage floating mica; wherein, the pulp concentration is 35%, the collector used in the flotation process is dodecylamine, and the reagent dosages for the three stages of flotation are 150g / t, 70g / t, and 50g / t respectively, based on m(reagent) / m(quartz sand), and the pH is controlled at 2.5;

[0168] (72) Three-stage pumice: Three-stage pumice is carried out after three-stage pumice; the pulp concentration is 35%, and the collectors used in the flotation process are sodium petroleum sulfonate and dodecylamine. The reagent dosages for the three stages of flotation are as follows, calculated by m (reagent) / m (quartz sand): First stage, 600 g / t of sodium petroleum sulfonate and 300 g / t of dodecylamine; Second stage, 300 g / t of sodium petroleum sulfonate and 150 g / t of dodecylamine; Third stage, 300 g / t of sodium petroleum sulfonate and 150 g / t of dodecylamine, with the pH controlled at 1.8.

[0169] (73) First stage of iron mineral flotation: After three stages of feldspar flotation, a first stage of iron mineral flotation is carried out; wherein, the pulp concentration is 35%, the collector used in the flotation process is sodium petroleum sulfonate, and the reagent dosage is 1000g / t based on m(reagent) / m(quartz sand); the pH is controlled at 2.5;

[0170] (8) First high-pressure acid leaching: The first flotation quartz concentrate is placed in acid solution and then placed in a reaction vessel and reacted at 220℃ for 5 hours, and washed until neutral; wherein, the mass-volume ratio of the first flotation quartz concentrate to the acid solution is 10g:50mL, and the acid solution is a mixture of hydrochloric acid solution, nitric acid solution and hydrofluoric acid solution, with the concentration of hydrochloric acid in the acid solution being 3mol / L, the concentration of nitric acid being 1mol / L and the concentration of hydrofluoric acid being 1mol / L;

[0171] (9) Secondary flotation: The acid-treated primary flotation quartz concentrate is subjected to secondary flotation to obtain secondary flotation quartz concentrate; wherein, the pulp concentration is 35%, the number of flotation stages is two, and the collectors used in the secondary flotation process are sodium petroleum sulfonate and dodecylamine. The reagent dosages for the two stages of flotation are as follows, calculated as m (reagent) / m (quartz sand): First stage, sodium petroleum sulfonate 400g / t, dodecylamine 200g / t; Second stage, sodium petroleum sulfonate 200g / t, dodecylamine 100g / t, and the pH is controlled at 1.8;

[0172] (10) Secondary calcination and water quenching: After calcining the secondary flotation quartz concentrate at 1000℃ for 2 hours, it is placed in water for water quenching;

[0173] (11) Secondary high-pressure acid leaching: The calcined and water-quenched quartz concentrate is placed in acid solution and then placed in a reaction vessel. It is reacted at 220℃ for 5 hours. After washing until neutral, it is dried to obtain high-purity quartz sand. The mass-volume ratio of the calcined and water-quenched quartz concentrate to the acid solution is 10g:50mL. The acid solution includes a mixture of hydrochloric acid solution, nitric acid solution and hydrofluoric acid solution. The concentration of hydrochloric acid in the acid solution is 3mol / L, the concentration of nitric acid is 1mol / L and the concentration of hydrofluoric acid is 1mol / L.

[0174] Performance testing

[0175] The high-purity quartz sands prepared according to the methods in Examples 1-3 and Comparative Examples 1-4 were tested respectively, and the SiO2 content of each high-purity quartz sand is shown in Table 1 below.

[0176] Table 1 - Test results of high-purity quartz sand obtained in Examples 1-3 and Comparative Examples 1-4

[0177] Example <![CDATA[Mass content of SiO2 / %]]> Example 1 99.9952 Example 2 99.9965 Example 3 99.9967 Comparative Example 1 99.9924 Comparative Example 2 99.9928 Comparative Example 3 99.9933 Comparative Example 4 99.9926

[0178] As shown in the table above, the SiO2 content of the high-purity quartz sand prepared in Examples 1-3 and Comparative Examples 1-4 is greater than 99.99%. Furthermore, as the preferred process, Examples 1-3 have SiO2 content of 99.9952%, 99.9965%, and 99.9967% in the concentrate, respectively.

[0179] Specifically, compared with other processes, the selected processes and their sequence in this process have significant advantages in the purification of Beihai quartz ore. See the specific embodiments for reference:

[0180] Comparative Example 1: Crushing - Pickling - Grinding - Gravity Separation - Magnetic Separation - Flotation - Calcination and Water Quenching - High-Pressure Acid Leaching.

[0181] Comparative Example 2: Crushing - Acid Washing - Grinding - Gravity Separation - Magnetic Separation - Flotation - First High-Pressure Acid Leaching - Calcination and Water Quenching - Second High-Pressure Acid Leaching.

[0182] Comparative Example 3: Crushing - Acid Washing - Grinding - Gravity Separation - Magnetic Separation - Primary Flotation - Primary High-Pressure Acid Leaching - Secondary Flotation - Calcination and Water Quenching - Secondary High-Pressure Acid Leaching.

[0183] Comparative Example 4: Crushing - Pickling - First Calcination and Water Quenching - Grinding - Gravity Separation - Magnetic Separation - First Flotation - First High-Pressure Acid Leaching - Second Flotation - Second Calcination and Water Quenching - Second High-Pressure Acid Leaching.

[0184] Comparative Example 2, based on Comparative Example 1, added a high-pressure acid leaching after flotation. This is beneficial for removing gangue minerals that have been liberated or attached to quartz in the quartz sand, including mica, feldspar, etc.

[0185] Comparative Example 3 adds a second flotation step to Comparative Example 2. The purpose of the second flotation step is to remove impurity quartz whose surface properties have changed after the first high-pressure acid leaching.

[0186] Comparative Example 4, based on Comparative Example 3, involved calcination and water quenching before grinding. After calcination and water quenching, the quartz sand developed numerous fissures, which is beneficial for the grinding process but also increases the risk of contamination from impurities entering the sand during subsequent processes. To improve the purity of the concentrate, this invention avoids calcination and water quenching before grinding.

[0187] Example 1, based on Comparative Example 3, added alkaline leaching to improve the activity of the quartz sand and enhance the effect of secondary high-pressure acid leaching.

[0188] Example 3 adds chlorination roasting to Example 1, which converts impurity elements such as sodium and lithium into gases and carries them out, further improving the purity of high-purity quartz sand.

[0189] In summary, this invention mainly uses Beihai quartz ore as raw material and proposes a high-purity purification process. The processed quartz sand achieves a high purity, with the SiO2 content in the quartz concentrate exceeding 99.995%.

[0190] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for producing high purity quartz sand using North Sea Group quartz, characterized by, The method comprises the following steps: S1, crushing: crushing the quartz raw ore to obtain quartz sand; S2, acid washing: soaking the crushed quartz sand in a hydrochloric acid solution; S3, grinding: washing the acid-washed quartz sand to neutral and then grinding; S4, gravity separation: performing gravity separation on the ground quartz sand; S5, magnetic separation: performing magnetic separation on the gravity-separated quartz sand; S6, primary flotation: performing flotation on the magnetic-separated quartz sand to obtain primary flotation quartz concentrate; S7, primary high-pressure acid leaching: placing the primary flotation quartz concentrate in an acid solution for primary high-pressure acid leaching, and then washing to neutral; S8, secondary flotation: performing secondary flotation on the primary high-pressure acid leaching primary flotation quartz concentrate to obtain secondary flotation quartz concentrate; S9, calcination and water quenching: calcining the secondary flotation quartz concentrate, and then placing it in water for water quenching; S10, alkali leaching: placing the calcined and water-quenched secondary flotation quartz concentrate in an alkali solution for alkali leaching, and then washing to neutral; S11, secondary high-pressure acid leaching: placing the alkali-leached quartz concentrate in an acid solution for secondary high-pressure acid leaching, and then washing to neutral to obtain high-purity quartz sand; wherein The quartz raw ore is from the North Sea area, and the mass content of SiO2 in the quartz raw ore is 99% to 99.95%; The primary flotation step comprises: S61, three-stage flotation of mica: performing three-stage flotation of mica on the magnetic-separated quartz sand; wherein the collector used in the flotation process is dodecylamine, and the flotation slurry concentration is 30% to 40%; according to m (reagent) / m (quartz sand), the reagent dosages of the three-stage flotation are as follows: 100g / t to 200g / t for the first stage, 50g / t to 100g / t for the second stage, and 40g / t to 60g / t for the third stage; the pH is controlled to be 2 to 3; S62, three-stage flotation of feldspar: performing three-stage flotation of feldspar on the quartz concentrate after the three-stage flotation of mica; wherein the collector used in the flotation process is sodium petroleum sulfonate and dodecylamine, and the flotation slurry concentration is 30% to 40%; according to m (reagent) / m (quartz sand), the reagent dosages of the three-stage flotation are as follows: 500g / t to 700g / t of sodium petroleum sulfonate and 200g / t to 400g / t of dodecylamine for the first stage, 200g / t to 400g / t of sodium petroleum sulfonate and 100g / t to 200g / t of dodecylamine for the second stage, and 200g / t to 400g / t of sodium petroleum sulfonate and 100g / t to 200g / t of dodecylamine for the third stage; the pH is controlled to be 1.5 to 2; S63, one-stage flotation of iron-containing minerals: performing one-stage flotation of iron-containing minerals on the quartz concentrate after the three-stage flotation of feldspar; wherein the collector used in the flotation process is sodium petroleum sulfonate, the flotation slurry concentration is 30% to 40%, and the reagent dosage is 800g / t to 1200g / t according to m (reagent) / m (quartz sand), and the pH is controlled to be 2 to 3; In the step of calcination and water quenching, the calcination temperature is 900°C to 1100°C, and the calcination time is 1h to 3h; In the step of alkali leaching, the alkali solution is at least one of a sodium hydroxide solution and a potassium hydroxide solution, the alkali concentration is 0.3mol / L to 0.7mol / L, the solid-liquid ratio is 1g: (2mL to 4mL), the alkali leaching temperature is 40°C to 80°C, and the alkali leaching time is 3h to 8h.

2. The method for preparing high purity quartz sand using North Sea Group quartz according to claim 1, characterized in that, In the crushing step, the quartz raw ore is crushed to a particle size of less than 5 mm; in the acid pickling step, the quartz sand is soaked in a hydrochloric acid solution for 12-24 h, the mass fraction of the hydrochloric acid solution is 5-10%, and the solid-liquid ratio of acid pickling is 1 g:(1-2) mL; in the grinding step, the grinding is performed to a mesh number of 40-140.

3. The method for preparing high purity quartz sand using North Sea Group quartz according to claim 1, characterized in that, In the first high-pressure acid leaching or the second high-pressure acid leaching step, the acid solution used includes at least one of a hydrochloric acid solution, a nitric acid solution and a hydrofluoric acid solution; the quartz concentrate and the acid solution are used in a ratio of 1 g:(2-10) mL; the temperature of acid leaching is 90-220 DEG C, and the time of acid leaching is 3-6 h.

4. The method for preparing high purity quartz sand using North Sea Group quartz according to claim 1, characterized in that, In the first high-pressure acid leaching or the second high-pressure acid leaching step, in the acid solution used, the concentration of hydrochloric acid is 0-4 mol / L, the concentration of nitric acid is 0-2 mol / L, and the concentration of hydrofluoric acid is 0-5 mol / L.

5. The method for preparing high purity quartz sand using North Sea Group quartz according to claim 1, characterized in that, In the second flotation step, the collector used is sodium petroleum sulfonate and dodecylamine, the pulp concentration is 30-40%, the number of flotation stages is two, and according to m (reagent) / m (quartz sand), in the first stage, the sodium petroleum sulfonate is 300-500 g / t, and the dodecylamine is 100-300 g / t; in the second stage, the sodium petroleum sulfonate is 100-300 g / t, and the dodecylamine is 80-120 g / t, and the pH is controlled to be 1.5-2.

6. The method for preparing high purity quartz sand using North Sea Group quartz according to claim 1, wherein the North Sea Group quartz is used as it is. Further comprising the following steps: S12, chlorination roasting: the quartz concentrate after the second high-pressure acid leaching is subjected to chlorination roasting to obtain high-purity quartz sand.

7. The method for preparing high purity quartz sand using North Sea Group quartz according to claim 6, characterized in that, In the chlorination roasting step, the temperature of the chlorination roasting is 800-1100 DEG C, the time of the chlorination roasting is 1-3 h, and the atmosphere of the chlorination roasting is hydrogen chloride.

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