Method for preparing high-purity quartz sand by taking weakly magnetic mineral-containing quartzite as raw material

Abstract

The invention discloses a method for preparing high-purity quartz sand by taking quartzite containing weak magnetic minerals as a raw material. The method comprises the steps of ore grinding, screening, magnetic separation and the following staged flotation: 1, under the condition that the pH value is 10-11, butyl xanthate is used as a collecting agent, first-stage flotation is carried out, and pyrite is removed; 2, under the condition that the pH value ranges from 5.0 to 5.5, styrene phosphonic acid serves as a collecting agent, second-stage flotation is conducted, and rutile is removed; 3, under the condition that the pH value ranges from 6.5 to 7.0, ether amine GE-609 serves as a collecting agent, third-stage flotation is conducted, and epidote is removed; 4, under the condition that the pH value ranges from 4.0 to 4.5, dodecylamine hydrochloride serves as a collecting agent, fourth-stage flotation is conducted, and garnet is removed; and finally, carrying out acid leaching, washing and drying to obtain the final quartz concentrate. According to the method, weakly magnetic mineral impurities can be effectively removed, the high-purity quartz sand with the purity of 4N7 can be prepared, and the purity of 4N8 can be achieved by combining a deep purification technology.

Description

Technical Field

[0001] The present invention relates to a method for preparing high-purity quartz sand, and particularly to a method for preparing high-purity quartz sand using weakly magnetic mineral-containing quartzite as a raw material, belonging to the technical field of mineral processing. Background Art

[0002] Quartzite is a metamorphic rock formed by regional metamorphism or thermal contact metamorphism of quartz sandstone or other siliceous rocks. Quartzite resources in China are very rich, and the exploitation and utilization volume is large. However, impurities in this type of quartz ore are generally more and the purification is relatively difficult. Its industrial applications are mainly concentrated in ferrosilicon, ferrosilicon raw materials with low added value, and quartz raw material products with ω(SiO2) of about 99% that are not affected by particle size and angularity factor. In recent years' research on the purification, detection and evaluation of quartzite ore, it has been found that some quartzite can be purified to high-purity quartz above 3N, and there are even individual quartzite with the potential to be purified and processed into high-end products of 4N8 high-purity quartz. Its industrial application scope and value have been seriously underestimated.

[0003] At present, a large amount of strongly magnetic and weakly magnetic impurities exist in the quartzite produced in most regions of China. The strongly magnetic impurities can be removed by magnetic separation, but the weakly magnetic impurities (mainly including pyrite, rutile, epidote, garnet) are more difficult to remove and need to be separated by flotation. Since the surface chemical properties of quartz and weakly magnetic minerals are similar, both mainly composed of silicon-oxygen bonds or metal-oxygen bonds, the selectivity of traditional collectors is insufficient. Especially under the interference of inevitable ions (Ca 2+ , Mg 2+ ), quartz is easily non-selectively activated, making it difficult to achieve effective separation. The pulp pH value has a significant impact on the flotation process. If single alkaline flotation is used, pyrite can be effectively removed, but the removal rate of epidote is low, and rutile and garnet are hardly separated. The optimal flotation pH ranges of weakly magnetic minerals and quartz often overlap, resulting in a narrow pH regulation window. Non-selective adsorption of collectors causes quartz to be entrained and float, with low recovery rate, unable to meet the purification requirements of high-purity quartz sand. When multiple impurities coexist, single flotation reagents or flotation conditions cannot meet the requirements, and multiple flotation operations are required, resulting in serious cross-interference of reagents. Therefore, it is difficult to obtain high-quality quartz sand from weakly magnetic mineral-containing quartzite.

[0004] At present, in the field of quartz sand purification, traditional purification process routes are generally directly used to purify different raw quartz ores. However, due to the associated gangue minerals, inclusions, lattice impurities, etc. in the raw quartz ores, the stable production of high-purity quartz sand cannot be achieved. Especially for the quartz sand purification process using quartzite as the raw material ore, there is even a one-ore-one-process flow. In the conventional flotation process, most only consider impurity types such as mica, feldspar, and iron-containing oxides, and no in-depth research has been done on weakly magnetic minerals such as pyrite, rutile, epidote, and garnet. In particular, there are almost no reports on separating quartz-epidote and quartz-garnet from quartzite by flotation.

[0005] In summary, there is currently a blank in the preparation process of high-purity quartz sand using weakly magnetic mineral-containing quartzite as the raw material. There is an urgent need to find a technology that can prepare high-purity quartz sand from weakly magnetic mineral-containing quartzite and is suitable for industrial mass production. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the deficiency that weakly magnetic minerals are difficult to effectively remove in the prior art, and provide a method for preparing high-purity quartz sand using weakly magnetic mineral-containing quartzite as the raw material. Through a special staged flotation process combined with precise pH value regulation, pyrite, rutile, epidote, and garnet can be effectively removed, and high-purity quartz sand with a purity of up to 4N7 can be prepared. Combining with deep purification technology, it can reach 4N8.

[0007] The present invention specifically adopts the following technical solutions to solve the above technical problems:

[0008] A method for preparing high-purity quartz sand using weakly magnetic mineral-containing quartzite as the raw material, comprising the following steps:

[0009] S1. Grind the raw quartzite ore to prepare raw quartz sand ore powder;

[0010] S2. Screen and classify the raw quartz sand ore powder, and screen out particles with a particle size of 80-160 mesh to obtain pretreated ore powder;

[0011] S3. Perform magnetic separation on the pretreated ore powder to remove strongly magnetic impurities and obtain magnetic separation quartz sand ore;

[0012] S4. Perform the following staged flotation on the magnetic separation quartz sand ore:

[0013] S4-1. Under the condition that the pH value is 10-11, use butyl xanthate as the collector to perform the first-stage flotation on the magnetic separation quartz sand ore to remove pyrite;

[0014] S4-2. Under the condition that the pH value is 5.0-5.5, use styrene phosphonic acid as the collector to perform the second-stage flotation on the magnetic separation quartz sand ore to remove rutile;

[0015] S4-3. At a pH value of 6.5 - 7.0, using ether amine GE-609 as a collector, conduct the third-stage flotation on the magnetic separation quartz sand ore to remove epidote;

[0016] S4-4. At a pH value of 4.0 - 4.5, using dodecylamine hydrochloride as a collector, conduct the fourth-stage flotation on the magnetic separation quartz sand ore to remove garnet;

[0017] S5. After acid leaching the quartz sand concentrate obtained by staged flotation, wash and dry it to obtain the final quartz concentrate.

[0018] Preferably, the staged flotation further includes a water washing process between each stage of flotation.

[0019] Preferably, the first to fourth stage flotation respectively includes one rough selection and 2 - 4 times of fine selection.

[0020] Preferably, in the first stage flotation, the pulp mass concentration is 20% - 30%; the dosage of the collector is 20 - 80 g / t; the quartz inhibitor is water glass, and the dosage is 300 - 400 g / t; the foaming agent is terpineol, and the dosage is 10 - 20 g / t.

[0021] Preferably, in the second stage flotation, the pulp mass concentration is 20% - 30%; the dosage of the collector is 20 - 70 g / t; the quartz inhibitors are sodium fluorosilicate and carboxymethyl cellulose, and the dosages are 20 - 50 g / t respectively; the foaming agent is terpineol, and the dosage is 10 - 20 g / t.

[0022] Preferably, in the third stage flotation, the pulp mass concentration is 20% - 30%; the dosage of the collector is 20 - 60 g / t; the quartz inhibitor is water glass, and the dosage is 150 - 200 g / t; the foaming agent is terpineol, and the dosage is 10 - 20 g / t.

[0023] Preferably, in the fourth stage flotation, the pulp mass concentration is 20% - 30%; the dosage of the collector is 20 - 60 g / t; the quartz inhibitor is water glass, and the dosage is 150 - 200 g / t; the foaming agent is terpineol, and the dosage is 10 - 20 g / t.

[0024] Further preferably, in the fourth stage flotation, 20 - 30 g / t of oxalic acid is also added as a garnet activator.

[0025] Preferably, a mixed acid composed of hydrochloric acid, sulfuric acid, nitric acid, and hydrofluoric acid solution is used for the acid leaching. Among them, the concentration of hydrochloric acid is 3 mol / L, the concentration of sulfuric acid is 3 mol / L, the concentration of nitric acid is 1 mol / L, and the concentration of hydrofluoric acid is 2 mol / L; the liquid-solid ratio of the mixed acid to the quartz sand concentrate is 1:3; the temperature of the acid leaching is 95 °C.

[0026] Furthermore, the method for preparing high-purity quartz sand further includes:

[0027] S6. Deeply purify the quartz concentrate.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention uses weakly magnetic mineral-containing quartzite as the raw material. Aiming at the problem of removing weakly magnetic minerals, a special staged flotation process is proposed. Using targeted flotation collectors and combined with precise pH value control, pyrite, rutile, epidote, and garnet are sequentially removed by flotation, effectively removing these weakly magnetic mineral impurities that are difficult to remove by traditional processes. Finally, high-purity quartz sand with a purity of up to 4N7 can be prepared. On this basis, combined with deep purification processes such as high-temperature chlorination, extremely high-purity quartz sand with a purity of 4N8 can be prepared; the present invention greatly expands the range of raw material selection for the preparation of high-purity quartz sand, effectively reducing the production cost, and providing a new process route for the optimized purification of weakly magnetic mineral-containing quartzite. Description of the Drawings

[0030] Figure 1 It is a process flow schematic diagram of the method for preparing high-purity quartz sand of the present invention. Detailed Embodiments

[0031] Aiming at the problem of removing weakly magnetic minerals in weakly magnetic mineral-containing quartzite, the solution idea of the present invention is to adopt a special staged flotation process, use targeted flotation collectors and combined with precise pH value control, and sequentially remove pyrite, rutile, epidote, and garnet by flotation, thereby effectively removing these weakly magnetic mineral impurities that are difficult to remove by traditional processes and obtaining high-purity quartz sand.

[0032] To remove different weakly magnetic impurities, the pH value of the quartz pulp needs to be adjusted in stages, gradually adjusted from strong alkalinity to weak acidity, and butyl xanthate, styrene phosphonic acid, ether amine GE-609, and dodecylamine hydrochloride are respectively used as the flotation collectors for pyrite, rutile, epidote, and garnet. The principles of the above collectors are as follows:

[0033] The collector for pyrite is butyl xanthate, and the flotation principle is that the thiocarbamate group of butyl xanthate forms a coordination bond with the exposed Fe on the surface of pyrite 2+Combined to form stable metal xanthate, the butyl chain of butyl xanthate extends outward to form a hydrophobic layer, reducing the hydrophilicity of the mineral surface and making it easy to attach to bubbles and float.

[0034] Styrene phosphonic acid is an effective collector for rutile. Its structure contains a hydrophobic group phenyl and a strong chelating group phosphonic acid group. The phosphonic acid group coordinates with Ti on the rutile surface through bidentate coordination 4+ Combined to form a stable five-membered ring chelate. At the same time, the phenyl group extends outward to form a hydrophobic layer, reducing the hydrophilicity of the mineral surface and significantly increasing the probability of bubble attachment.

[0035] As a collector for epidote, ether amine GE-609 separates it from quartz by utilizing the synergistic effect of its characteristic chemical adsorption. At pH 6-8, Fe 3+ / Al 3+ exposed in the epidote crystal structure can form a coordination bond with the amino group (-NH 3+ ) of GE-609. The oxygen atom in the ether bond forms a stable hydrogen bond with the hydroxyl group on the epidote surface, enhancing the adsorption stability. At the same time, the long-chain alkyl group in ether amine GE-609 forms a dense hydrophobic film, significantly improving the bubble attachment efficiency.

[0036] The collector for garnet is dodecylamine hydrochloride. Under weak acid conditions, the surface of garnet is negatively charged due to the dissociation of silicon-oxygen tetrahedrons. The cationic dodecylamine in dodecylamine hydrochloride is adsorbed on the negatively charged region of the garnet surface through electrostatic interaction. The amino group forms a hydrogen bond or weak coordination bond with Al on the surface, enhancing the adsorption stability. The long-chain alkyl group in dodecylamine hydrochloride extends outward to form a dense hydrophobic layer, making it easy to attach to bubbles and float. 3+ forming a hydrogen bond or weak coordination bond, enhancing the stability of adsorption. The long-chain alkyl group in dodecylamine hydrochloride extends outward to form a dense hydrophobic layer, making it easy to attach to bubbles and float.

[0037] The preparation method of high-purity quartz sand using weakly magnetic mineral-containing quartzite as raw material proposed by the present invention, as Figure 1 shown, specifically includes the following steps:

[0038] S1. Grind the raw material quartzite ore to prepare the raw ore powder of quartz sand;

[0039] S2. Screen and classify the raw ore powder of quartz sand, and screen out particles with a particle size of 80-160 mesh to obtain the pretreated ore powder;

[0040] S3. Perform magnetic separation on the pretreated ore powder to remove strongly magnetic impurities and obtain the magnetically separated quartz sand ore;

[0041] S4. Perform the following staged flotation on the magnetically separated quartz sand ore:

[0042] S4-1. Under the condition of pH value of 10-11, use butyl xanthate as the collector to perform the first-stage flotation on the magnetically separated quartz sand ore to remove pyrite;

[0043] S4-2. Under the condition that the pH value is 5.0 - 5.5, using styrene phosphonic acid as the collector, conduct the second-stage flotation on the magnetic-separated quartz sand ore to remove rutile;

[0044] S4-3. Under the condition that the pH value is 6.5 - 7.0, using ether amine GE-609 as the collector, conduct the third-stage flotation on the magnetic-separated quartz sand ore to remove epidote;

[0045] S4-4. Under the condition that the pH value is 4.0 - 4.5, using dodecylamine hydrochloride as the collector, conduct the fourth-stage flotation on the magnetic-separated quartz sand ore to remove garnet;

[0046] S5. After acid leaching the quartz sand concentrate obtained by staged flotation, wash and dry it to obtain the final quartz concentrate.

[0047] To remove the residual reagents to ensure the effectiveness of pH regulation and avoid the influence of the interaction between reagents on flotation, preferably, the staged flotation further includes a water washing process between each stage of flotation.

[0048] To further improve the flotation effect, each stage of flotation can adopt a multi-stage flotation process. Preferably, the first to fourth stages of flotation respectively include one rough selection and 2 - 4 times of fine selection. A higher collector dosage is used during rough selection, and the collector dosage can be appropriately reduced during fine selection.

[0049] Preferably, in the first-stage flotation, the pulp mass concentration is 20% - 30%; the collector dosage is 20 - 80 g / t; the quartz inhibitor is water glass, and the dosage is 300 - 400 g / t; the foaming agent is terpineol, and the dosage is 10 - 20 g / t.

[0050] Preferably, in the second-stage flotation, the pulp mass concentration is 20% - 30%; the collector dosage is 20 - 70 g / t; the quartz inhibitors are sodium fluorosilicate and carboxymethyl cellulose, and the dosages are 20 - 50 g / t respectively; the foaming agent is terpineol, and the dosage is 10 - 20 g / t.

[0051] Preferably, in the third-stage flotation, the pulp mass concentration is 20% - 30%; the collector dosage is 20 - 60 g / t; the quartz inhibitor is water glass, and the dosage is 150 - 200 g / t; the foaming agent is terpineol, and the dosage is 10 - 20 g / t.

[0052] Preferably, in the fourth-stage flotation, the pulp mass concentration is 20% - 30%; the collector dosage is 20 - 60 g / t; the quartz inhibitor is water glass, and the dosage is 150 - 200 g / t; the foaming agent is terpineol, and the dosage is 10 - 20 g / t.

[0053] In order to further improve the flotation effect of garnet, it is further preferred that in the fourth stage flotation, oxalic acid in an amount of 20-30 g / t is added as a garnet activator.

[0054] Preferably, the acid leaching is carried out using a mixed acid formed by mixing hydrochloric acid, sulfuric acid, nitric acid and hydrofluoric acid solutions, wherein the concentration of hydrochloric acid is 3 mol / L, the concentration of sulfuric acid is 3 mol / L, the concentration of nitric acid is 1 mol / L, and the concentration of hydrofluoric acid is 2 mol / L; the liquid-solid ratio of the mixed acid to the quartz sand concentrate is 1:3; and the temperature of the acid leaching is 95°C.

[0055] Furthermore, the method for preparing high-purity quartz sand also includes:

[0056] S6. Deeply purify the quartz concentrate.

[0057] In order to facilitate public understanding, the technical solution of the present invention is described in detail below through a specific embodiment:

[0058] The raw material used in this embodiment is quartzite containing weak magnetic minerals produced in Lianyungang, Jiangsu Province. The main mineral composition of the ore is 92.5% quartz, 1.2% pyrite, 0.8% rutile, 3.5% epidote, and 1.0% garnet. The preparation process of high-purity quartz sand using it as raw material is as follows:

[0059] (1) Grinding: The raw ore is crushed into small particles by a jaw crusher, and further ground by a rod mill for 5 minutes to prepare quartz sand raw ore powder.

[0060] (2) Screening: The quartz sand ore powder obtained in step (1) is screened and graded using a sample sieve, wherein the screening method is wet screening, and particles with a particle size of 80-160 mesh are screened out, accounting for about 45.8%, to obtain pre-treated ore powder;

[0061] (3) Magnetic separation: The quartz sand ore powder obtained in step (2) is subjected to magnetic separation using a strong magnetic rod to remove strong magnetic impurities and obtain magnetically separated quartz sand ore. The strength of the magnetic rod is 13,000 gauss and the magnetic separation time is 10-20 min.

[0062] (4) Removal of pyrite by flotation: Control the solid content of the pulp at 20%-30%. In the roughing operation, add lime to the pulp to adjust the pH value to 10.5; add 70 g / t of butyl xanthate as a pyrite collector; add 350 g / t of water glass as a quartz depressant, stir for 5 min, then add 15 g / t of terpineol as a frother, inflate and scrape the foam, and the flotation time is 5-10 min to obtain the rough concentrate of quartz; conduct two cleaning operations on the rough concentrate, add 25 g / t of butyl xanthate as a pyrite collector; add 350 g / t of water glass as a quartz depressant, stir for 5 min, then add 15 g / t of frother, inflate and scrape the foam, and the flotation time is 5-10 min.

[0063] (5) Removal of rutile by flotation: Wash the quartz sand pulp obtained in step (4) several times to remove residual reagents; add an appropriate amount of water to adjust the pulp, control the solid content of the pulp at 20%-30%, and adjust the pH value of the quartz pulp to 5.2 with sulfuric acid; add 60 g / t of styrene phosphonic acid as a rutile collector, 40 g / t of sodium fluorosilicate as a quartz depressant, and 20 g / t of carboxymethyl cellulose as a quartz depressant in the roughing stage, stir for 5 min, then add 15 g / t of terpineol as a frother, inflate and scrape the foam, and the flotation time is 5-10 min to obtain the rough concentrate of quartz; conduct two cleaning operations on the rough concentrate, add 20 g / t of styrene phosphonic acid as a rutile collector, 40 g / t of sodium fluorosilicate as a quartz depressant, and 20 g / t of carboxymethyl cellulose as a quartz depressant, stir for 5 min, then add 15 g / t of frother, inflate and scrape the foam, and the flotation time is 5-10 min.

[0064] (6) Removal of epidote by flotation: Wash the quartz sand pulp obtained in step (5) several times to remove residual reagents; add an appropriate amount of water to adjust the pulp, control the solid content of the pulp at 20%-30%, and adjust the pH of the pulp to 6.8; add 50 g / t of ether amine GE-609 as an epidote collector and 150 g / t of water glass as a quartz depressant in the roughing stage, stir for 5 min, then add 15 g / t of terpineol as a frother, inflate and scrape the foam, and the flotation time is 5-10 min to obtain the rough concentrate of quartz; conduct two cleaning operations on the rough concentrate, add 20 g / t of ether amine GE-609 as an epidote collector and 150 g / t of water glass as a quartz depressant, stir for 5 min, then add 15 g / t of terpineol as a frother, inflate and scrape the foam, and the flotation time is 5-10 min.

[0065] (7) Flotation to remove garnet: The quartz sand pulp obtained in step (6) is washed with water multiple times to remove residual reagents; an appropriate amount of water is added to adjust the pulp, and the solid content of the pulp is controlled at 20%-30%. The pH of the pulp is adjusted to 4.3 with sulfuric acid. In the roughing stage, 50 g / t of dodecylamine hydrochloride, a garnet collector, 25 g / t of oxalic acid, an activator, and 150 g / t of water glass, a quartz inhibitor, are added. After stirring for 5 min, 15 g / t of terpineol, a foaming agent, is added, and air is inflated and foamed. The flotation time is 5-10 min to obtain rough quartz concentrate. The rough concentrate is subjected to two-stage cleaning. 20 g / t of dodecylamine hydrochloride, a garnet collector, 25 g / t of oxalic acid, a garnet activator, and 150 g / t of water glass, a quartz inhibitor, are added. After stirring for 5 min, 15 g / t of foaming agent is added, and air is inflated and foamed. The flotation time is 5-10 min.

[0066] (8) Acid leaching: The quartz sand concentrate obtained after flotation in step (7) is fully washed with water and then transferred to a container made of polytetrafluoroethylene. A mixed acid solution is added according to a liquid-solid ratio of 1:3. The mixed acid is a mixture of hydrochloric acid, sulfuric acid, nitric acid, and hydrofluoric acid solutions. The molar concentration of hydrochloric acid is 3 mol / L, the molar concentration of sulfuric acid is 3 mol / L, the molar concentration of nitric acid is 1 mol / L, and the molar concentration of hydrofluoric acid is 2 mol / L. The acid leaching temperature is 95 °C and the time is 6 hours. After acid leaching is completed, it is washed with ultrapure water until neutral and dried to obtain the final quartz concentrate.

[0067] The content of impurity elements in the finally obtained quartz sand concentrate is measured by HR ICP-MS. The specific content of impurity elements is shown in Table 1. The sum of the contents of impurity elements is less than 30 ppm, and the SiO2 content reaches 99.997%, belonging to medium and high-end high-purity quartz sand products.

[0068] Table 1 Impurity element content of high-purity quartz sand 10 -6

[0069] Element Li Na Mg Al P K Ca Ti Cr Content 0.99 2.02 0.3 12.6 0.061 0.041 1.14 5.42 <0 Element Mn Fe Co Ni Cu Zn ∑ <![CDATA[SiO2 (%)]]> Purity Content 0.097 6.45 <0 <0 0.26 0.12 29.499 99.997 4N7

[0070] The high-purity quartz sand prepared by the above process can reach a purity of 4N8 after further deep purification treatment by methods such as high-temperature chlorination, fluoride complexation purification, microbial leaching, and supercritical fluid extraction, thus meeting the high-end application requirements in fields such as photovoltaics, electric light sources, and optical communications. Therefore, the technical solution of the present invention is of great significance for improving the domestic production rate of high-end high-purity quartz sand and reducing the import ratio.

Claims

1. A method for preparing high-purity quartz sand using weakly magnetic mineral-containing quartzite as a raw material, characterized in that, It includes the following steps: S1. Grind the raw material quartzite ore to prepare the raw ore powder of quartz sand; S2. Screen and classify the raw ore powder of quartz sand, screen out the particles with a particle size of 80 - 160 mesh to obtain the pretreated ore powder; S3. Conduct magnetic separation on the pretreated ore powder to remove strongly magnetic impurities and obtain the magnetically separated quartz sand ore; S4. Conduct the following staged flotation on the magnetically separated quartz sand ore: S4 - 1. Under the condition that the pH value is 10 - 11, use butyl xanthate as the collector to conduct the first - stage flotation on the magnetically separated quartz sand ore to remove pyrite; S4 - 2. Under the condition that the pH value is 5.0 - 5.5, use styrene phosphonic acid as the collector to conduct the second - stage flotation on the magnetically separated quartz sand ore to remove rutile; S4 - 3. Under the condition that the pH value is 6.5 - 7.0, use ether amine GE - 609 as the collector to conduct the third - stage flotation on the magnetically separated quartz sand ore to remove epidote; S4 - 4. Under the condition that the pH value is 4.0 - 4.5, use dodecylamine hydrochloride as the collector to conduct the fourth - stage flotation on the magnetically separated quartz sand ore to remove garnet; S5. After acid leaching the quartz sand concentrate obtained from the staged flotation, wash and dry it to obtain the final quartz concentrate.

2. The method for preparing high-purity quartz sand according to claim 1, wherein, The staged flotation also includes a water - washing process between each stage of flotation.

3. The method for preparing high-purity quartz sand according to claim 1, wherein, The first to fourth - stage flotation respectively include one roughing and 2 - 4 cleanings.

4. The method for preparing high-purity quartz sand according to claim 1, wherein In the first - stage flotation, the pulp mass concentration is 20% - 30%; the collector dosage is 20 - 80 g / t; the quartz inhibitor is water glass, and the dosage is 300 - 400 g / t; the foaming agent is terpineol, and the dosage is 10 - 20 g / t.

5. The method for preparing high-purity quartz sand according to claim 1, wherein, In the second - stage flotation, the pulp mass concentration is 20% - 30%; the collector dosage is 20 - 70 g / t; the quartz inhibitors are sodium fluorosilicate and carboxymethyl cellulose, and the dosages are 20 - 50 g / t respectively; the foaming agent is terpineol, and the dosage is 10 - 20 g / t.

6. The method for preparing high-purity quartz sand according to claim 1, wherein, In the third - stage flotation, the pulp mass concentration is 20% - 30%; the collector dosage is 20 - 60 g / t; the quartz inhibitor is water glass, and the dosage is 150 - 200 g / t; the foaming agent is terpineol, and the dosage is 10 - 20 g / t.

7. The method for preparing high-purity quartz sand according to claim 1, characterized in that, In the fourth - stage flotation, the pulp mass concentration is 20% - 30%; the collector dosage is 20 - 60 g / t; the quartz inhibitor is water glass, and the dosage is 150 - 200 g / t; the foaming agent is terpineol, and the dosage is 10 - 20 g / t.

8. The preparation method of high-purity quartz sand according to claim 7, wherein, In the fourth - stage flotation, 20 - 30 g / t of oxalic acid is also added as the garnet activator.

9. The method for preparing high-purity quartz sand according to claim 1, wherein, The acid leaching is carried out using a mixed acid composed of hydrochloric acid, sulfuric acid, nitric acid, and hydrofluoric acid solution. Among them, the hydrochloric acid concentration is 3 mol / L, the sulfuric acid concentration is 3 mol / L, the nitric acid concentration is 1 mol / L, and the hydrofluoric acid concentration is 2 mol / L; the liquid - to - solid ratio of the mixed acid to the quartz sand concentrate is 1:3; the acid - leaching temperature is 95 °C.

10. The method for preparing high-purity quartz sand according to any one of claims 1 to 9, characterized in that, It also includes: S6. Conduct deep purification on the quartz concentrate.

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