Purification method of granite pegmatite

Abstract

The invention particularly discloses a granite pegmatite purification method. The method comprises the steps of pretreatment, primary flotation, drying purification, water quenching, acidification, secondary flotation and drying. According to the method, the quartz sand is subjected to primary flotation before drying and purification, so that most associated minerals in the quartz sand can be removed, and the material cost in the subsequent purification and acidification process is saved; meanwhile, the drying purification process and the low-temperature water quenching process are combined together, the quartz sand dried at the front end is directly purified, lattice impurities in the preheated quartz sand in the drying process can react with a purifying agent more efficiently, and the purified quartz sand can directly flow into a skip car filled with liquid nitrogen at the high temperature; on one hand, larger temperature difference can be achieved, and on the other hand, the materials can be prevented from being polluted in the transferring process. Therefore, the granite pegmatite purification method provided by the invention can effectively remove lattice impurities in the quartz sand, and has the characteristics of simple process and high purification efficiency.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of quartz sand purification, and particularly relates to a method for purifying granitic pegmatite. BACKGROUND

[0002] High-purity quartz sand is an important inorganic non-metallic material, which plays a key role in many high-tech fields due to its excellent physical and chemical properties. With the progress of science and technology, the application field of high-purity quartz sand is still expanding, and its application in the fields of national defense technology and thin film materials is also increasingly concerned. As a raw material for preparing high-purity quartz sand, the quartz purity of many granitic pegmatites can reach more than 97%, but how to further purify it to 4N8 or even 5N and above is a common problem, especially for the lattice impurities in quartz sand, there is no effective method for deep removal.

[0003] At present, the purification method of high-purity quartz sand is mostly calcination, water quenching, acidification and flotation. The purification method is relatively simple, first, after simple calcination and water quenching, part of the gas-liquid inclusions can be removed; then, through acidification and flotation, most of the associated mineral impurities can be removed to obtain a roughly purified product. However, for granitic pegmatite, this purification method is relatively inefficient, and excessive use of reagents will lead to rising costs, and the calcination process will change the chemical properties of associated minerals, making it difficult to remove later. In addition, this purification method has little effect on the removal of lattice impurities.

[0004] Therefore, how to efficiently remove impurities in granitic pegmatite is a technical problem to be solved by the technical personnel in the technical field. SUMMARY

[0005] The present application is made in view of the above technical problems. The purpose is to provide a method for purifying granitic pegmatite, which comprises:

[0006] Pretreatment, pretreating the quartz raw ore to obtain quartz sand with a predetermined particle size;

[0007] Primary flotation, under a first predetermined temperature condition, based on a pre-configured first flotation liquid, the pretreated quartz sand is subjected to primary flotation, and the quartz sand after primary flotation is subjected to cleaning, wherein the first predetermined temperature is 40-50℃;

[0008] Drying and purification, the quartz sand after primary flotation and cleaning is sequentially input into a drying pipe and a quartz pipe connected in series for drying and purification, wherein the temperature in the drying pipe is 500-750℃, and the temperature in the quartz pipe is 1100-1300℃;

[0009] Water quenching, connecting the material car containing liquid nitrogen with the quartz tube discharge port, and then water quenching the quartz sand output from the quartz tube discharge port;

[0010] Acidification, acidifying the water quenched quartz sand at a second preset temperature condition using a mixed acid, wherein the second preset temperature is 90-120°C.

[0011] Secondary flotation, secondary flotation of the acidified quartz sand at a first preset temperature condition based on a preconfigured second flotation liquid, and cleaning the secondary floated quartz sand.

[0012] Drying, drying the secondary floated and cleaned quartz sand to remove the water in the quartz sand.

[0013] In some embodiments, the pretreatment specifically comprises: first, crushing the quartz raw ore to obtain a semi-finished product with a particle size of 4-6 cm; then, acid quenching the obtained semi-finished product, and crushing and screening the acid quenched semi-finished product to obtain quartz sand with a preset particle size of 70-180 mesh.

[0014] In some embodiments, during the primary flotation process, the preconfigured first flotation liquid is a mixed hydrochloride salt, and the pretreated quartz sand is floated using the mixed hydrochloride salt until the foam runs out, wherein the mixed hydrochloride salt comprises: dodecylamine hydrochloride 500 g / t, hexadecylamine hydrochloride 500 g / t, and octadecylamine hydrochloride 500 g / t, and the pH value of the mixed hydrochloride salt is 2-4.

[0015] In some embodiments, the cleaning of the primary floated quartz sand specifically comprises: first, rinsing the primary floated quartz sand with pure water for 2-4 times, then cleaning with ethanol for 2-4 times, and finally cleaning with deionized water for 2-4 times.

[0016] In some embodiments, during the drying and purifying process, the purifying agent in the quartz tube is at least one of Freon R22, Freon R12, Freon R32, and Freon R134a.

[0017] In some embodiments, during the acidification process, the mass ratio of the mixed acid to the quartz sand is 2-1:1, and the acidification time is 10-14 hours, wherein the mixed acid comprises hydrochloric acid and hydrofluoric acid in a volume ratio of 5-3:1, the mass fraction of hydrochloric acid is 37%, and the mass fraction of hydrofluoric acid is 50%.

[0018] In some embodiments, during the secondary flotation process, the preconfigured second flotation liquid is used to secondary float the acidified quartz sand until the foam runs out, wherein the second flotation liquid comprises: dodecylamine hydrochloride 500 g / t and dodecyl sulfonate sodium sulfate 250 g / t, and the pH value of the second flotation liquid is 2-3.

[0019] In some embodiments, the cleaning of the quartz sand after the secondary flotation is specifically as follows: first, the quartz sand after the secondary flotation is washed with pure water for 2-4 times, then washed with ethanol for 2-4 times, and finally washed with deionized water for 2-4 times.

[0020] In some embodiments, the quartz sand after the secondary flotation is transported to a high-purity quartz tube for drying to remove the moisture in the quartz sand, wherein the temperature in the high-purity quartz tube is 850-950℃.

[0021] Compared with the prior art, the granite pegmatite purification method provided by the application has the following beneficial technical effects:

[0022] (1) The application performs primary flotation on the quartz sand before drying and purification, thereby removing most of the associated minerals in the quartz sand and saving the material cost in the subsequent purification and acidification processes;

[0023] (2) The application combines the drying and purification process with the low-temperature water quenching process, so that the quartz sand dried at the front end is directly subjected to purification, the lattice impurities in the quartz sand preheated during the drying process can more efficiently react with the purification agent, and the quartz sand after purification can also directly flow into the car filled with liquid nitrogen while being at high temperature, which can achieve a greater temperature difference on the one hand and avoid contamination during the material transfer process on the other hand;

[0024] (3) The application uses at least one of freon R22, freon R12, freon R32 and freon R134a in the purification process, which is less toxic and more environmentally friendly than the chlorine and hydrogen chloride gas in the prior art, and has stronger ability to remove lattice impurities;

[0025] (4) The application acidifies the quartz sand after purification, which can effectively remove the lattice impurities that have migrated to the surface of the quartz sand and have not been timely removed, so that the purity of the quartz sand after final purification is higher.

[0026] In summary, the granite pegmatite purification method provided by the application can effectively remove the lattice impurities in the quartz sand, thereby improving the purity of the quartz sand product, and has the characteristics of simple process and high purification efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the application or the technical solutions in the prior art, the drawings needed in the following specific embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0028] Figure 1 is a process flow chart of the method for purifying granitic pegmatite in the present application. DETAILED DESCRIPTION

[0029] The ranges disclosed herein are defined by the endpoints as modified by "about" to allow for variations that are outside the stated range. Unless otherwise specified, a range "a-b" is intended to encompass a range from the lower point a to the upper point b and all the individual integers within that range. For example, unless otherwise specified, a range of "0-5" is intended to encompass all the integers between 0 and 5, e.g., 0, 1, 2, 3, 4, and 5. It is also to be understood that all ranges and combinations of ranges recited herein are meant to be literally encompassed by the language of the claims. For example, a range of "a-b" is a shorthand way of referring to each and every number that is between a and b, inclusive of the endpoints. It is specifically intended that the scope of the claims include all equivalents falling within the scope of the claims.

[0030] Reference Figure 1 As shown in the figure, the embodiment of the present application provides a method for purifying granitic pegmatite, which comprises the following steps:

[0031] Preprocessing, preprocessing the quartz raw ore to obtain quartz sand with a preset particle size;

[0032] Specifically, first, the quartz raw ore is crushed to obtain a semi-finished product with a particle size of 4-6 cm; then, the obtained semi-finished product is subjected to acid quenching, and the semi-finished product after acid quenching is crushed and sieved to obtain quartz sand with a preset particle size of 70-180 mesh.

[0033] Primary flotation, under a first preset temperature condition, the quartz sand after preprocessing is subjected to primary flotation based on a pre-configured first flotation liquid, and the quartz sand after primary flotation is cleaned, wherein the first preset temperature is 40-50°C;

[0034] In this step, by adding a primary flotation process in the front-end process, most of the associated minerals in the quartz raw ore can be effectively removed, thereby saving the cost of raw materials in the subsequent purification and acidification process. The first flotation liquid is a mixed hydrochloride. The quartz sand after pretreatment is floated at a first preset temperature using the mixed hydrochloride, and the foam is run out. Then the quartz sand after the first flotation is washed 2-4 times with pure water, 2-4 times with ethanol, and finally 2-4 times with deionized water. The mixed hydrochloride includes: dodecylamine hydrochloride 500g / t, hexadecylamine hydrochloride 500g / t, and octadecylamine hydrochloride 500g / t. The pH value of the mixed hydrochloride is 2-4, and the pH value of the mixed hydrochloride is adjusted with hydrofluoric acid.

[0035] In this step, the first preset temperature can be any value between 40-50℃, for example, the first preset temperature can be 40℃, 42℃, 44℃, 46℃, 48℃, 50℃, etc. The pH value of the mixed hydrochloride can be any value between 2-4, for example, the pH value of the mixed hydrochloride can be adjusted to 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4, etc.

[0036] Dry purification, the quartz sand after the first flotation washing is sequentially input into the dry tube and the quartz tube connected in series for drying and purification, wherein the temperature in the dry tube is 500-750℃, and the temperature in the quartz tube is 1100-1300℃.

[0037] In this step, the purification agent in the quartz tube can be at least one of freon R22, freon R12, freon R32, and freon R134a. In this embodiment, freon R22 is selected as the purification agent in the quartz tube. Compared with hydrogen chloride or chlorine, freon R22 is more environmentally friendly and less toxic as a purification agent, and freon R22 has stronger ability to remove lattice impurities.

[0038] In this step, the dry tube for drying the quartz sand and the quartz tube for purifying the quartz sand are connected in series as a whole. The quartz sand after drying in the dry tube is directly input into the quartz tube for the next purification. In this way, the dry tube can preheat the quartz sand, which helps the quartz sand to react more efficiently with the purification agent in the quartz tube, so that the lattice impurities in the quartz sand are removed more thoroughly. The temperature in the dry tube can be any value between 500-750℃, for example, the temperature in the dry tube can be 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, etc. The temperature in the quartz tube can be any value between 1100-1300℃, for example, the temperature in the quartz tube can be 1100℃, 1150℃, 1200℃, 1250℃, 1300℃, etc.

[0039] Water quenching involves connecting a material cart filled with liquid nitrogen to the outlet of a quartz tube, thereby quenching the quartz sand output from the outlet of the quartz tube.

[0040] In this step, the trolley containing liquid nitrogen is directly connected to the outlet of the quartz tube. In this way, the quartz sand purified by the purifying agent in the quartz tube falls directly into the trolley containing liquid nitrogen, achieving a greater temperature difference while effectively preventing the quartz sand from being contaminated.

[0041] Acidification: Under a second preset temperature condition, water-quenched quartz sand is acidified using a mixed acid, wherein the second preset temperature is 90-120℃.

[0042] In this step, the mixed acid removes lattice impurities that migrate from the interior of the quartz sand to its surface during the purification process, ensuring the purification of the quartz sand. The mass ratio of the mixed acid to the quartz sand can be any value between 2 and 1:1; for example, the mass ratio can be 2:1, 1.5:1, 1:1, etc. The acidification time can be any value between 10 and 14 hours; for example, the acidification time can be 10 hours, 10.5 hours, 11 hours, 11.5 hours, 12 hours, 12.5 hours, 13 hours, 13.5 hours, 14 hours, etc. The second preset temperature can be any value between 90 and 120℃; for example, the second preset temperature can be 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, etc.

[0043] In this step, the mixed acid includes hydrochloric acid and hydrofluoric acid in a volume ratio of 5-3:1, with hydrochloric acid having a mass fraction of 37% and hydrofluoric acid having a mass fraction of 50%. The volume ratio of hydrochloric acid to hydrofluoric acid can be any ratio between 5 and 3:1. For example, the volume ratio of hydrochloric acid to hydrofluoric acid can be 5:1, 4:1, 3:1, etc.

[0044] Secondary flotation: Under the first preset temperature condition, the acidified quartz sand is subjected to secondary flotation based on the pre-configured second flotation solution, and the quartz sand after secondary flotation is washed.

[0045] In this step, impurities in the quartz sand can be further removed by secondary flotation. Specifically, the acidified quartz sand is first subjected to secondary flotation using a pre-prepared second flotation solution until the foam is removed. Then, the quartz sand after secondary flotation is washed 2-4 times with pure water, then washed 2-4 times with ethanol, and finally washed 2-4 times with deionized water. The second flotation solution includes 500g / t of dodecylamine hydrochloride and 250g / t of sodium dodecyl sulfate. The pH value of the second flotation solution is adjusted to 2-3 with sulfuric acid.

[0046] In this step, the pH value of the second flotation liquid can be any value between 2 and 3, and for example, the pH value of the mixed hydrochloride can be adjusted to 2, 2.2, 2.4, 2.6, 2.8, 3, etc.

[0047] Drying, the quartz sand washed by the secondary flotation is dried to remove the moisture in the quartz sand.

[0048] In this step, the quartz sand washed by the secondary flotation is transported into the high-purity quartz tube for drying, and the drying temperature in the high-purity quartz tube is between 850-950°C, and for example, the drying temperature in the high-purity quartz tube can be 850°C, 860°C, 870°C, 880°C, 890°C, 900°C, 910°C, 920°C, 930°C, 940°C, 950°C, etc.

[0049] In the above embodiment, first, a primary flotation process is added in the front-end process to remove most of the associated minerals in the quartz raw ore, thereby saving raw materials for subsequent purification and acidification processes; second, the drying purification and low-temperature water quenching processes are combined together, on the one hand, the quartz sand preheated after drying treatment can be directly put into the purification process, so that the lattice impurities in the quartz sand can react more efficiently with the purifying agent, on the other hand, the purified quartz sand can also be directly transported into the car filled with liquid nitrogen at high temperature, which avoids the pollution of the quartz sand while achieving a larger temperature difference, and moreover, freon R22 is selected as the purifying agent, which is more environmentally friendly and has stronger ability to remove lattice impurities than hydrogen chloride or chlorine in the prior art. Therefore, the granite pegmatite purification method provided by the present application can effectively remove the lattice impurities in the quartz sand, thereby improving the purity of the quartz sand product, and has the characteristics of simple process and high purification efficiency.

[0050] The following examples more specifically describe the disclosure of the present application, which are only used for illustrative purposes, because various modifications and changes within the scope of the disclosure of the present application are obvious to those skilled in the art. Unless otherwise stated, all reagents and raw materials used in the examples are commercially available or synthesized according to conventional methods, and the instruments and equipment used in the examples are commercially available.

[0051] Example 1

[0052] 1) The quartz raw sand is crushed to obtain semi-finished ore with a particle size of 4-6 cm, and then the obtained semi-finished ore is acid leached and crushed and sieved to obtain quartz sand with a particle size of 70-180 mesh;

[0053] 2) in the first preset temperature is 40 ℃ condition, using pH value is 4 mixed hydrochloride to the quartz sand obtained in step 1) is floated once, after the foam runs clean through pure water washing 2 times, in using anhydrous ethanol cleaning 2 times, finally with deionized water cleaning 2 times;

[0054] 3) the quartz sand of step 2) is input in the drying tube and quartz tube connected in series and is dried and purified, wherein the drying temperature in the drying tube is 500 DEG C, the purification temperature in the quartz tube is 1100 DEG C, and the purification agent is freon R22;

[0055] 4) the purified quartz sand is input into the car with liquid nitrogen and is water quenched;

[0056] 5) in the second preset temperature is 90 ℃ condition, using mixed to the quartz sand after water quenching is acidified, mixed acid is the volume ratio of hydrochloric acid and hydrofluoric acid 5:1, the mass ratio of mixed acid and quartz sand is 2:1, and the acidification time is 10 hours;

[0057] 6) in the temperature is 40 ℃ condition, using the second flotation liquid to the quartz sand after acidification is floated twice, after the flotation to the foam runs clean, use pure water washing 2 times, then through ethanol cleaning 2 times, with deionized water cleaning 2 times, wherein the pH value of the second flotation liquid is 2;

[0058] 7) the quartz sand after the second cleaning is transported to the high-purity quartz tube with a temperature of 850 DEG C to dry, remove the moisture in the quartz sand, and obtain high-purity quartz sand.

[0059] Example 2

[0060] 1) the selected quartz sand is crushed to obtain semi-finished ore with a particle size of 4-6 cm, and then the obtained semi-finished ore is acid leached and crushed and sieved to obtain quartz sand with a particle size of 70-180 mesh;

[0061] 2) in the first preset temperature is 45 ℃ condition, using pH value is 3 mixed hydrochloride to the quartz sand obtained in step 1) is floated once, after the foam runs clean through pure water washing 3 times, in using anhydrous ethanol cleaning 3 times, finally with deionized water cleaning 3 times;

[0062] 3) the quartz sand after the first cleaning of step 2) is input in the drying tube and quartz tube connected in series and is dried and purified, wherein the drying temperature in the drying tube is 650 DEG C, the purification temperature in the quartz tube is 1200 DEG C, and the purification agent is freon R22;

[0063] 4) the purified quartz sand is input into the car with liquid nitrogen and is water quenched;

[0064] 5) under the condition of the second preset temperature of 110℃, the mixed acid is used to acidize the water-quenched quartz sand, the mixed acid is hydrochloric acid and hydrofluoric acid with the volume ratio of 4:1, the mass ratio of the mixed acid to the quartz sand is 3:2, and the acidizing time is 12 hours;

[0065] 6) under the condition of the temperature of 45℃, the second flotation liquid is used to perform secondary flotation on the acidized quartz sand, after the flotation is completed, the quartz sand is washed with pure water for 3 times, then washed with ethanol for 3 times, and washed with deionized water for 3 times, wherein the pH value of the second flotation liquid is 2.5;

[0066] 7) the quartz sand after the secondary flotation and washing is transported into a high-purity quartz tube with the temperature of 900℃ to perform drying, so as to remove the water in the quartz sand, and high-purity quartz sand is obtained.

[0067] Example 3

[0068] 1) the selected quartz raw sand is crushed to obtain semi-finished ore with the particle size of 4-6cm, then the obtained semi-finished ore is subjected to acid leaching and then crushed and sieved to obtain quartz sand with the particle size of 70-180 mesh;

[0069] 2) under the condition of the first preset temperature of 50℃, the mixed hydrochloride with the pH value of 2 is used to perform primary flotation on the quartz sand obtained in step 1), after the foam is completely removed, the quartz sand is washed with pure water for 4 times, washed with anhydrous ethanol for 4 times, and finally washed with deionized water for 4 times;

[0070] 3) the quartz sand after the primary flotation and washing in step 2) is input into a drying tube and a quartz tube connected in series to perform drying and purification, wherein the drying temperature in the drying tube is 750℃, the purification temperature in the quartz tube is 1300℃, and the purification agent is freon R22;

[0071] 4) the purified quartz sand is input into a car loaded with liquid nitrogen which is directly connected to the discharge port of the quartz tube to perform water quenching;

[0072] 5) under the condition of the second preset temperature of 120℃, the mixed acid is used to acidize the water-quenched quartz sand, the mixed acid is hydrochloric acid and hydrofluoric acid with the volume ratio of 3:1, the mass ratio of the mixed acid to the quartz sand is 1:1, and the acidizing time is 14 hours;

[0073] 6) under the condition of the temperature of 50℃, the second flotation liquid is used to perform secondary flotation on the acidized quartz sand, after the flotation is completed, the quartz sand is washed with pure water for 4 times, then washed with ethanol for 4 times, and washed with deionized water for 4 times, wherein the pH value of the second flotation liquid is 3;

[0074] 7) the quartz sand after the secondary flotation and washing is transported into a high-purity quartz tube with the temperature of 950℃ to perform drying, so as to remove the water in the quartz sand, and high-purity quartz sand is obtained.

[0075] Comparative Example 1

[0076] The same as Example 1, except that there is no one-time flotation in step 2).

[0077] Comparative Example 2

[0078] The same as Example 2, except that in step 3), the drying tube and the quartz tube are not connected in series, but the quartz sand dried in the drying tube is transported into the quartz tube for purification by transfer, and the purifying agent in the quartz tube is hydrogen chloride.

[0079] Comparative Example 3

[0080] The same as Example 3, except that in step 4), the trolley containing liquid nitrogen and the discharge port of the quartz tube are not directly connected, but the quartz sand purified in the quartz tube is transported into the trolley containing liquid nitrogen by transfer.

[0081] The high-purity quartz sand obtained in Examples 1-3 and Comparative Examples 1-3 is analyzed for impurity content, and the results are shown in Table 1.

[0082] Table 1: Impurity content results of high-purity quartz sand obtained in Examples 1-3 and Comparative Examples 1-3

[0083]

[0084]

[0085] In Table 1, the units of various impurity contents are ppm. As can be seen from Table 1, the total impurity content of Examples 1-3 is below 13.5 ppm, while the total impurity content of Comparative Examples 1-3 is above 19.3 ppm. Therefore, the total impurity content of Examples 1-3 is significantly lower than that of Comparative Examples 1-3.

[0086] Compared with Example 1, since there is no one-time flotation of quartz ore in the front end in Comparative Example 1 to remove associated minerals in the quartz ore, the reaction of lattice impurities with the purifying agent in the subsequent purification process is not complete, resulting in a higher total impurity content of the quartz sand obtained finally.

[0087] Compared with Example 2, since the drying tube and the quartz tube are not connected in series in Comparative Example 2, the temperature of the quartz sand transported into the quartz tube for purification is lower, and compared with Example 2, the reaction of lattice impurities in the quartz sand with the purifying agent is not complete. Moreover, the purifying agent in the quartz tube is hydrogen chloride, which has a lower ability to remove lattice impurities than Freon R22. Therefore, the total impurity content of the quartz sand obtained in Comparative Example 2 is higher.

[0088] Compared with Example 3, in Comparative Example 3, the water quenching device is not directly connected with the discharge port of the quartz tube, the temperature difference between the quartz sand and the trolley containing liquid nitrogen is small, the water quenching effect is poor, and there is a risk of contamination, resulting in a higher total impurity content of the quartz sand obtained in Comparative Example 3;

[0089] In summary, in the granite pegmatite purification method provided in the present application, a first flotation process is added at the front end, and the drying purification and water quenching processes are effectively combined, thereby significantly improving the removal effect of lattice impurities in the quartz sand.

[0090] The above describes in detail a granite pegmatite purification method provided in the present application. The principles and implementation modes of the present application are described by applying specific examples, and the above description of the examples is only used to help understand the core idea of the present application. It should be pointed out that, for those skilled in the art, some improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A method for purifying granite pegmatite, characterized in that, The method includes: Pretreatment involves pretreating the raw quartz ore to obtain quartz sand with a predetermined particle size. In the first flotation, under the first preset temperature condition, the pretreated quartz sand is subjected to a first flotation based on a pre-configured first flotation solution, and the quartz sand after the first flotation is washed. The first preset temperature is 40-50℃. Drying and purification: Quartz sand washed by flotation is sequentially fed into a drying tube and a quartz tube connected in series for drying and purification. The temperature inside the drying tube is 500-750℃, and the temperature inside the quartz tube is 1100-1300℃. Water quenching involves connecting a material cart filled with liquid nitrogen to the outlet of a quartz tube, thereby quenching the quartz sand output from the outlet of the quartz tube. Acidification: Under a second preset temperature condition, water-quenched quartz sand is acidified using a mixed acid, wherein the second preset temperature is 90-120℃. Secondary flotation: Under the first preset temperature condition, the acidified quartz sand is subjected to secondary flotation based on the pre-configured second flotation solution, and the quartz sand after secondary flotation is washed. Drying: The quartz sand after secondary flotation washing is dried to remove moisture from the quartz sand.

2. The method for purifying granite pegmatite as described in claim 1, characterized in that, The pretreatment process includes: first, jaw crushing the raw quartz ore to obtain a semi-finished product with a particle size of 4-6 cm; then, acid quenching the obtained semi-finished product, and then crushing and screening the acid-quenched semi-finished product to obtain quartz sand with a preset particle size of 70-180 mesh.

3. The method for purifying granite pegmatite as described in claim 1, characterized in that, In one flotation process, the first flotation solution is a mixed hydrochloride. The pretreated quartz sand is floated using the mixed hydrochloride until the foam is removed. The mixed hydrochloride includes 500 g / t of dodecylamine hydrochloride, 500 g / t of hexadecylamine hydrochloride and 500 g / t of octadecylamine hydrochloride. The pH value of the mixed hydrochloride is 2-4.

4. The method for purifying granite pegmatite as described in claim 3, characterized in that, The specific steps for cleaning the quartz sand after the first flotation are as follows: First, rinse the quartz sand after the first flotation with pure water 2-4 times, then clean it with ethanol 2-4 times, and finally clean it with deionized water 2-4 times.

5. The method for purifying granite pegmatite as described in claim 1, characterized in that, During the drying and purification process, the purifying agent in the quartz tube is at least one of Freon R22, Freon R12, Freon R32 and Freon R134a.

6. The method for purifying granite pegmatite as described in claim 1, characterized in that, During the acidification process, the mass ratio of the mixed acid to the quartz sand is 2-1:1, and the acidification time is 10-14 hours. The mixed acid includes hydrochloric acid and hydrofluoric acid in a volume ratio of 5-3:1, with the hydrochloric acid having a mass fraction of 37% and the hydrofluoric acid having a mass fraction of 50%.

7. The method for purifying granite pegmatite as described in claim 1, characterized in that, In the secondary flotation process, the acidified quartz sand is subjected to secondary flotation using a pre-prepared second flotation solution until the foam is removed. The second flotation solution includes 500 g / t of dodecylamine hydrochloride and 250 g / t of sodium dodecyl sulfate, and the pH value of the second flotation solution is 2-3.

8. The method for purifying granite pegmatite as described in claim 7, characterized in that, The specific steps for cleaning the quartz sand after secondary flotation are as follows: First, rinse the quartz sand after secondary flotation with pure water 2-4 times, then clean it with ethanol 2-4 times, and finally clean it with deionized water 2-4 times.

9. The method for purifying granite pegmatite as described in claim 1, characterized in that, The quartz sand after secondary flotation is transported to a high-purity quartz tube for drying to remove moisture from the quartz sand. The temperature inside the high-purity quartz tube is 850-950℃.

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