Quartz sand purification method and quartz sand laser purification device

Abstract

The application discloses a quartz sand purification method and a quartz sand laser purification device, and relates to the field of quartz sand purification methods.The quartz sand purification method comprises the following steps: step one, crushing and screening quartz sand ore to obtain quartz sand raw materials; step two, pretreating and sorting the quartz sand raw materials to obtain quartz sand to be purified; step three, pre-purifying the quartz sand to be purified; step four, laser purifying the quartz sand after pre-purification, wherein the laser purification method is a laser directional gasification treatment method; step five, repeating the operation of steps three and four for 0-5 times after step four is completed; and step six, cleaning and drying the quartz sand after step four to obtain purified quartz sand.The application avoids the problems existing in the purification of quartz sand by means of recrystallization after melting or internal grain melting, thereby improving the quartz sand purification efficiency and quality, relatively reducing energy consumption, and saving cost.

Description

Technical Field

[0001] This invention belongs to the field of inorganic material purification, specifically relating to methods and apparatus for purifying quartz sand. Background Technology

[0002] Quartz sand, with SiO2 as its main component, is a basic raw material for high-tech industries such as photovoltaic optical fiber, semiconductor, communications, and aerospace. With the rapid development of these fields, the demand for high-purity quartz sand is also increasing.

[0003] Traditionally, quartz sand is prepared through deep purification of quartz minerals. The removal of impurities in quartz sand can be categorized into microbial, physical, and chemical methods. Microbial methods are the latest development and are currently in the research stage of laboratory and small-scale experiments, insufficient for industrial production. Chemical methods require quartz sand to be melted and recrystallized or purified after melting, but these methods are energy-intensive, time-consuming, and involve complex processes. High control over crystal form and purity is also crucial during recrystallization, significantly reducing purification efficiency and increasing costs. Due to geological and topographical issues, my country has limited quartz sand reserves and no large deposits, making efficient and high-quality quartz sand purification an urgent priority.

[0004] Therefore, how to purify quartz sand efficiently and with high quality has become an urgent problem to be solved in this field. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a method for purifying quartz sand and a laser purification device for quartz sand. After pre-purifying the quartz sand by acid washing to remove surface metallic impurities, the internal impurities are removed by laser-directed gasification. This avoids the problems associated with quartz sand requiring melting and recrystallization or internal grain melting for purification, thereby improving the efficiency and quality of quartz sand purification while relatively reducing energy consumption and saving costs.

[0006] According to one aspect of the present invention, a method for purifying quartz sand is provided, characterized by comprising the following steps: Step 1, crushing and screening quartz sand ore to obtain quartz sand raw material;

[0007] Step 2: Pre-treat and sort the quartz sand raw material to obtain quartz sand to be purified;

[0008] Step 3: Pre-purify the quartz sand to be purified;

[0009] Step 4: The pre-purified quartz sand is then subjected to laser purification, wherein the laser purification method is laser directional gasification.

[0010] Step 5: After completing Step 4, repeat Step 3 and Step 4 0-5 times;

[0011] Step 6: Wash and dry the quartz sand after the operation in Step 5 to obtain purified quartz sand; the content of metal impurities in the purified quartz sand is ≤25μg / g, preferably; the content of metal impurities in the purified quartz sand is less than ≤20μg / g.

[0012] The impurity content in quartz sand obtained by traditional purification methods is 24-25 ug / g.

[0013] Compared with the prior art, the beneficial effects of the present invention are that by pre-treating and sorting the quartz sand raw material, the clay and other adhering substances on the surface of the quartz sand raw material are removed, and the particles containing a large amount of magnetic associated mineral impurities are removed, as well as the mica and feldspar minerals contained therein, the purified quartz sand containing no non-magnetic impurities such as mica and feldspar minerals and containing a low amount of magnetic impurities is obtained. This process does not require heating or chemical reaction, the process is simple and consumes little energy.

[0014] Pre-purification treatment removes metallic impurities from the surface layer;

[0015] Impurities present inside the quartz sand are removed by laser-directed vaporization (directed heating is to crack the impurity inclusions, which is beneficial for the subsequent acid washing to remove metal ions). The laser heats only the impurity-containing areas and does not require melting or fusion of the local quartz sand grains, thus not affecting the quartz sand grain structure and eliminating the need for recrystallization of the heated areas. This improves efficiency and saves energy.

[0016] Depending on the required purity of the quartz sand, steps three and four can be repeated 0-5 times to finally obtain purified quartz sand with a metal impurity content of less than 20 μg / g and high purity.

[0017] Further, the specific process of step one is as follows: after crushing the quartz sand ore with crushing equipment, it is screened with a 325-30 mesh screen to obtain quartz sand raw material with a particle size of 45-550μm.

[0018] The advantage of the previous step is that it achieves a quartz sand raw material that is both conducive to purification and avoids the quartz sand raw material having a particle size that is too small, which is not conducive to the processing and use after purification.

[0019] Furthermore, the specific process of pre-treating and sorting the quartz sand raw material in step two is as follows:

[0020] The quartz sand raw material is cleaned to remove surface deposits;

[0021] The quartz sand raw material is then subjected to magnetic separation, and then non-magnetic mineral impurities in the quartz sand raw material are removed by fluorine-free flotation; the non-magnetic mineral impurities include mica minerals and feldspar minerals.

[0022] Preferably, the quartz sand raw material is subjected to magnetic separation. First, the quartz sand raw material is screened using a weak magnetic separator or a medium magnetic separator with a magnetic field strength of 1000-6000 Oe. The screened quartz sand raw material is then passed through a wet strong magnetic separator with a magnetic field strength of 6000-10000 Oe to obtain magnetically separated quartz sand particles.

[0023] Then, a three-stage flotation method is used to remove mica and feldspar minerals from the quartz sand;

[0024] Primary flotation involves flotating magnetically separated quartz sand particles in a neutral or weakly acidic first slurry environment, which includes fatty acids (soap) and tall oil, to remove iron-containing clayey materials from the slurry.

[0025] Secondary flotation is carried out in a neutral or weakly acidic second slurry environment, the second slurry including amine collectors, to remove mica minerals and intergrowths of mica and quartz from the slurry; tertiary flotation is carried out in a neutral or weakly acidic third slurry environment, the third slurry including fatty acids and sulfonated petroleum, to remove feldspar minerals and intergrowths of feldspar and quartz from the slurry.

[0026] The beneficial effect of the previous step is that magnetic separation is an effective method to remove a large number of magnetic impurities from quartz sand raw materials; that is, through the magnetic separation process, quartz sand raw materials containing a large number of intergrowth particles, such as hematite, limonite and biotite, are effectively removed.

[0027] When the raw materials contain weakly magnetic mineral impurities such as hematite, limonite and biotite, a wet high-intensity magnetic separator is used to screen them out; while for strongly magnetic minerals containing mainly magnetite, a weak magnetic separator or a medium magnetic separator is used for separation.

[0028] Magnetic separation removes the quartz sand raw material containing a large amount of magnetic impurities. At the same time, it magnetizes the small amount of metal impurities in the quartz sand particles obtained after screening. This is beneficial for locating the impurities in the quartz sand during subsequent laser directional gasification treatment, as magnetism can be used for further precise positioning.

[0029] Fluorine-free flotation utilizes the differences in the structural composition of quartz and feldspar. By rationally adjusting the ratio and dosage of the mixed anion and cation collectors, and taking advantage of their different zeta potentials, feldspar is preferentially floated out, thus achieving separation.

[0030] Furthermore, the pre-purification process in step three is as follows: the quartz sand to be purified is mixed with the first acid solution at a mass ratio of (4.5-5.5):1, the surface of the quartz sand is acid-washed once, and then dried after the acid wash;

[0031] The first acid solution is a mixed solution of nitric acid and hydrochloric acid, and the hydrogen ion concentration in the first acid solution is 1.2-1.8 mol / L; the mass ratio of HCl to HNO3 in the first acid solution is 1:1; the first acid washing time is 3-8 hours.

[0032] The advantage of the previous step is that the first acid solution is used to acid wash the quartz sand to be purified, removing the impurities remaining on the surface of the quartz sand after the second step.

[0033] Furthermore, the laser-directed vaporization treatment method in step four includes the following steps:

[0034] The pre-purified quartz sand is directionally adjusted and laser-heated to locally heat the internal impurities;

[0035] The specific process is as follows: the pre-purified quartz sand is immersed in the first treatment solution, with the part of the quartz sand containing impurities facing the laser. Then, the part of the quartz sand containing impurities is directionally heated by the laser, and the laser irradiation time is 0.1-3 seconds.

[0036] The first treatment solution includes nitric acid; the hydrogen ion concentration in the first treatment solution is 0.5-0.8 mol / L; the temperature of the first treatment solution is 20-50℃; preferably, the first treatment solution also includes hydrochloric acid, and the mass ratio of HCl to HNO3 is 1:1.

[0037] Preferably, after the quartz sand is soaked in the first treatment solution, the parts of the quartz sand containing impurities are first subjected to directional magnetic positioning, that is, the quartz sand in the first treatment solution is placed in a directional magnetic field, and the parts containing metal impurities are oriented towards the magnetic pole direction; more preferably, the magnetic field strength of the directional magnetic positioning is greater than 10000 Oe.

[0038] Preferably, the metallic impurity is one or more of Al, Fe, Mg, Ti, and Na.

[0039] The beneficial effect of the previous step is that by immersing the pre-purified quartz sand in the first treatment liquid, the impurity inclusions in the quartz sand, due to their low internal density, are positioned so that the impurity-containing parts of the quartz sand face the upper surface of the first treatment liquid. The laser is positioned above the upper surface of the first treatment liquid, so that the impurity-containing parts of the quartz sand face the laser. Ultimately, the laser can directionally heat the impurity inclusions in the quartz sand, avoiding the problem of the impurity inclusions in the quartz sand not being heated by the laser. At the same time, it further helps to avoid heating the quartz sand crystals.

[0040] By further directional magnetic positioning, the orientation of the parts of the quartz sand containing impurities can be fixed, thus providing conditions for directional laser irradiation.

[0041] By momentarily irradiating the impurity-containing areas with a laser, the ultrashort, high-energy pulse generated by the laser is focused into the quartz sand being processed through an optical path. The laser energy at the focal point within the inclusions is far higher than the damage threshold of the inclusions themselves. The laser beam is absorbed at this location and converted into heat energy, causing a rapid increase in temperature within the inclusions. This rapid temperature increase has two effects: firstly, it causes vaporization or plasmaification within the gas-liquid inclusions, allowing gaseous and liquid impurities such as H2O, CO2, H2, and O2 to detach from the quartz sand matrix; secondly, the difference in thermal expansion coefficients between the internal inclusions and the quartz sand matrix due to the rapid temperature rise creates microcracks. Water quenching exacerbates the crack propagation, which is beneficial for subsequent acid pickling operations. This step removes metallic impurities, or subsequent acid pickling can remove other metallic impurities contained within the inclusions.

[0042] The laser irradiation time is 0.1-3s; that is, the energy is absorbed by the impurity inclusions, causing them to expand internally, while avoiding the influence of the laser on the internal crystals of the quartz sand; and the treatment liquid can be sprayed when the internal temperature and pressure of the impurity inclusions are high after laser irradiation, so as to achieve a large internal temperature difference and break them.

[0043] Meanwhile, the energy of the laser at the focal point of the inclusions inside the quartz sand is not absorbed or is only partially absorbed by the quartz sand grains, and does not cause the quartz sand grains to soften, melt or fused. Thus, the structure of the quartz sand crystals is not affected while removing impurities.

[0044] This method is simple and consumes little energy;

[0045] The temperature of the first treatment solution is 20-50℃. The first treatment solution is beneficial for the directional laser heating of the heated quartz sand followed by water quenching, and for the inclusions of impurities inside the quartz sand to rupture after expansion due to laser irradiation.

[0046] Preferably, the treatment solution also includes HNO3, and the molar concentration of HNO3 in the treatment solution is 0.5-0.8 mol / L; that is, while water quenching, internal metal impurities are also cleaned away; since the temperature of the treatment solution will be relatively high, the concentration of nitric acid needs to be reduced.

[0047] Furthermore, the laser-directed vaporization treatment method in step four also includes the following steps:

[0048] After being treated with laser irradiation, the quartz sand is mixed with the second acid solution for a second acid wash, which takes 3-8 hours.

[0049] The second acid solution is a mixed solution of nitric acid and hydrochloric acid, and the hydrogen ion concentration in the second acid solution is 0.5-0.8 mol / L; the mass ratio of HCl to HNO3 in the second acid solution is (0.5-0.8):1.

[0050] The beneficial effect of the previous step is that after laser irradiation and water quenching of the impurity inclusions in the quartz sand, the secondary acid washing helps to wash out the internal metal impurities, further improving the purity of the quartz sand; and because the temperature is high or rises during the water quenching process, it is necessary to reduce the concentration of the treatment solution.

[0051] Furthermore, in step four, before the quartz sand undergoes secondary acid washing after laser irradiation treatment, the quartz sand is mixed with a second treatment solution, which includes water and nitric acid; the hydrogen ion concentration in the second treatment solution is 0.5-0.8 mol / L; and the temperature of the second treatment solution is 15-25℃.

[0052] The beneficial effect of the previous step is that by spraying the second treatment liquid onto the quartz sand immediately after laser irradiation for 0.1-3 seconds, the second treatment liquid can be sprayed when the internal temperature and pressure of the impurity inclusions that have not been broken after laser irradiation are high, so that the impurity inclusions will be broken due to the large temperature difference between the inside and outside of the inclusions.

[0053] The water quenching process involves the use of hydrochloric acid and nitric acid in the treatment solution, which further facilitates the removal of internal metal impurities.

[0054] Furthermore, the output wavelength of the laser is 532 or 1064 nm, and the power is 60-5000 W; preferably, the output wavelength of the laser is 532 nm, and the power is 200-350 W.

[0055] The advantages of the previous step are that using a wavelength of 532nm facilitates rapid absorption by the impurity inclusions and a rapid increase in temperature, which is conducive to the vaporization or plasmaization of the impurity inclusions in a very short time, thus facilitating the rupture of the impurity inclusions. At the same time, with a power of 200-350W, while achieving the rupture of the impurity inclusions, the internal quartz sand receives less heat energy as a whole, which has very little impact on the quartz sand grains and saves energy.

[0056] According to another aspect of the present invention, a quartz sand laser purification apparatus is provided, through which a quartz sand laser purification method is implemented;

[0057] The quartz sand laser purification device includes a frame, a magnetic suction device, a laser, a spraying mechanism, and a conveyor purification belt; the spraying mechanism includes several nozzles.

[0058] The conveyor belt for purification is connected to the frame drive.

[0059] The conveyor purification treatment belt is equipped with several baffles, and side skirts are connected to both sides of the conveyor purification treatment belt.

[0060] The surface of the purification belt is divided into several accommodating spaces by the baffle and the side skirt, and the accommodating spaces can move along the frame with the purification belt;

[0061] The magnetic suction device, laser, and nozzle are located above the conveyor purification processing belt;

[0062] The magnetic suction device and laser are connected to the frame or base;

[0063] The laser's light-emitting end is perpendicular to the magnetic suction device. The magnetic suction device and the laser's light-emitting end are respectively connected to the connecting plate. The laser's light-emitting end is located directly below the magnetic suction device.

[0064] The distance between the nozzle and the light emitting end of the laser in the horizontal direction is 1-20cm.

[0065] Preferably, the side apron has several pleats and is made of an elastic material; more preferably, the side apron is made of rubber.

[0066] Preferably, the spraying mechanism further includes a connecting pipe, a storage tank, and a power unit, and the nozzle is connected to the power unit and the storage tank through the connecting pipe;

[0067] Preferably, the light emitting end of the laser is arranged perpendicularly to the plane of the magnetic attraction device, and the magnetic attraction device and the laser are connected to the frame or base through a connecting plate.

[0068] Compared with the prior art, the beneficial effect of the present invention is that the quartz sand laser purification device realizes the laser purification of the pre-purified quartz sand in the quartz sand purification method.

[0069] The purification process utilizes a conveyor belt with a surface divided into several accommodating spaces. Quartz sand is conveyed within these spaces while simultaneously undergoing laser-directed vaporization via an overhead laser. This vaporization or plasmaization of impurity inclusions within the quartz sand results in high internal gas temperature and expansion. Before laser irradiation, a treatment liquid is sprayed onto the quartz sand through nozzles above the conveyor belt. The quartz sand is immersed in the treatment liquid, with the portion containing impurity inclusions facing the laser, facilitating targeted laser irradiation. Following irradiation, water quenching is performed, causing the expanded impurity inclusions to rupture. Thus, impurities are washed out. The treatment liquid contains a certain concentration of nitric acid, which further facilitates the removal of metallic impurities from the inclusions during water quenching.

[0070] The nozzle can also spray a second treatment solution for water quenching and pickling again;

[0071] The laser's light-emitting end is set perpendicular to the plane of the magnetic attraction device. The magnetic attraction device provides a strong magnetic field to the quartz sand immersed in the first treatment liquid, which further facilitates the orientation of the inclusions toward the laser's light-emitting end.

[0072] Furthermore, the quartz sand laser purification device also includes a liquid storage tank, which is located directly below one end of the frame.

[0073] The advantage of the previous step is that by setting up a storage tank, while collecting the quartz sand and the treatment liquid, a second acid solution can be added to the storage tank to clean away residual impurities and improve the purity of the quartz sand. Attached Figure Description

[0074] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments of the present invention will be described below.

[0075] Figure 1 This is a schematic diagram of the structure of Embodiment 2 of the present invention.

[0076] In the diagram: 1. Nozzle; 2. Laser; 3. Magnetic suction device; 4. Frame; 5. Baffle; 6. Connecting plate; 7. Pre-purified quartz sand; 8. Storage tank. Detailed Implementation

[0077] To better understand the technical solution of the present invention, the present invention will be further described below with reference to specific embodiments.

[0078] Example 1:

[0079] One aspect of this embodiment provides a method for purifying quartz sand, characterized by comprising the following steps:

[0080] Step 1: Crushing and screening the quartz sand ore to obtain quartz sand raw material; the specific process is as follows: after crushing the quartz sand ore with crushing equipment, it is screened with a 325-30 mesh screen to obtain quartz sand raw material with a particle size of 45-550μm.

[0081] Step 2: Pre-treat and sort the quartz sand raw material to obtain the quartz sand to be purified; the specific process is as follows:

[0082] The quartz sand raw material is cleaned to remove surface deposits;

[0083] The quartz sand raw material is then subjected to magnetic separation, followed by fluorine-free flotation to remove non-magnetic mineral impurities, including mica and feldspar minerals.

[0084] Quartz sand raw material is first subjected to magnetic separation using a weak magnetic separator with a magnetic field strength of 4000 Oe. The quartz sand raw material obtained after screening is then passed through a wet strong magnetic separator with a magnetic field strength of 8000 Oe to obtain magnetically separated quartz sand particles.

[0085] Then, a three-stage flotation method is used to remove mica and feldspar minerals from the quartz sand;

[0086] Primary flotation involves flotating magnetically separated quartz sand particles in a neutral or weakly acidic first slurry environment, which includes fatty acids (soap) and tall oil, to remove iron-containing clayey materials from the slurry.

[0087] Secondary flotation is carried out in a neutral or weakly acidic second slurry environment, the second slurry including amine collectors, to remove mica minerals and intergrowths of mica and quartz from the slurry; tertiary flotation is carried out in a neutral or weakly acidic third slurry environment, the third slurry including fatty acids and sulfonated petroleum, to remove feldspar minerals and intergrowths of feldspar and quartz from the slurry.

[0088] Step 3: Pre-purify the quartz sand to be purified; the specific process is as follows: mix the quartz sand to be purified with the first acid solution at a mass ratio of 5:1, perform a first acid wash on the surface of the quartz sand, and then dry it after the first acid wash.

[0089] The first acid solution is a mixed solution of nitric acid and hydrochloric acid, and the hydrogen ion concentration in the first acid solution is 1.5 mol / L; the mass ratio of HCl to HNO3 in the first acid solution is 1:1; the first acid washing time is 6 hours.

[0090] The metallic impurities are one or more of Al, Fe, Mg, Ti, and Na.

[0091] Step 4: The pre-purified quartz sand 7 is subjected to laser purification. The laser purification method is laser-directed gasification. The laser-directed gasification method includes the following steps:

[0092] Pre-purified quartz sand is directionally adjusted and laser-heated to locally heat the impurities inside.

[0093] The specific process is as follows: the pre-purified quartz sand is immersed in the first treatment solution, with the part of the quartz sand containing impurities facing the laser 2; after the quartz sand is immersed in the first treatment solution, the part of the quartz sand containing impurities is oriented magnetically, that is, the quartz sand in the first treatment solution is placed in an oriented magnetic field, with some parts containing metal impurities facing the magnetic pole direction; the magnetic field strength of the oriented magnetic positioning is 12000 Oe;

[0094] Then, the impurity-containing parts of the quartz sand are directionally heated by laser 2, and the laser irradiation time is 1.5s; the output wavelength of laser 2 is 1064nm and the power is 1000W.

[0095] The first treatment solution includes water, nitric acid, and hydrochloric acid; the hydrogen ion concentration in the first treatment solution is 0.7 mol / L; the temperature of the first treatment solution is 30°C; and the mass ratio of HCl to HNO3 is 1:1.

[0096] Step 5: After completing Step 4, do not repeat Steps 3 and 4.

[0097] Step 6: Wash and dry the quartz sand after the operation in Step 4 to obtain purified quartz sand; the content of metal impurities in the purified quartz sand is 23 μg / g.

[0098] One aspect of this embodiment provides a quartz sand laser purification device, through which a quartz sand laser purification method is implemented;

[0099] The quartz sand laser purification device includes a frame 4, a magnetic suction device 3, a laser 2, a spraying mechanism, and a conveying purification belt; the spraying mechanism includes a nozzle 1; the spraying mechanism also includes a connecting pipe, a storage tank, and a power unit, and the nozzle 1 is connected to the power unit and the storage tank through the connecting pipe;

[0100] The conveyor belt for purification is connected to the frame 4 via a transmission.

[0101] The conveyor purification treatment belt is provided with several baffles 5, and side skirts are connected to both sides of the conveyor purification treatment belt; the side skirts are provided with several pleated structures and are made of elastic material; more preferably, the side skirts are made of rubber material.

[0102] The surface of the purification belt is divided into several accommodating spaces by the baffle 5 and the side skirt, and the accommodating spaces can move along the frame 4 with the purification belt.

[0103] The magnetic suction device 3, laser 2, and nozzle 1 are located above the conveyor purification treatment belt;

[0104] The magnetic suction device 3 and the laser 2 are connected to the frame 4 or the base;

[0105] The light emitting end of the laser 2 is perpendicular to the magnetic suction device 3. The magnetic suction device 3 and the light emitting end of the laser 2 are respectively connected to the connecting plate 6. The light emitting end of the laser 2 is located directly below the magnetic suction device 3.

[0106] The horizontal distance between the nozzle 1 and the light emitting end of the laser 2 is 1.5cm.

[0107] The light emitting end of the laser 2 is set perpendicular to the plane of the magnetic suction device 3. The magnetic suction device 3 and the laser 2 are connected to the frame 4 or the base through the connecting plate 6.

[0108] Example 2:

[0109] The content that is the same as in Example 1 will not be repeated here; the differences between this embodiment and Example 1 are as follows:

[0110] One aspect of this embodiment provides a method for purifying quartz sand;

[0111] The purified quartz sand contains 20 μg / g of metallic impurities; the laser-directed gasification treatment method in step four also includes the following steps:

[0112] After being irradiated by laser and quenched in a treatment solution, the quartz sand is mixed with a second acid solution for a second pickling process, which lasts for 4 hours.

[0113] The second acid solution is a mixed solution of nitric acid and hydrochloric acid, with a hydrogen ion concentration of 0.7 mol / L; the mass ratio of HCl to HNO3 in the second acid solution is 0.7:1.

[0114] The quartz sand to be purified is pre-purified; the specific process is as follows: the quartz sand to be purified is mixed with the first acid solution at a mass ratio of 4.6:1, the surface of the quartz sand is acid-washed once, and then dried after the acid wash.

[0115] The first acid solution is a mixed solution of nitric acid and hydrochloric acid, and the hydrogen ion concentration in the first acid solution is 1.3 mol / L; the mass ratio of HCl to HNO3 in the first acid solution is 1:1; the first acid washing time is 7 hours.

[0116] Then, the impurity-containing parts of the quartz sand are directionally heated by laser 2, with a laser irradiation time of 0.3s; the output wavelength of laser 2 is 532nm and the power is 220W.

[0117] The first treatment solution includes water, nitric acid, and hydrochloric acid; the hydrogen ion concentration in the first treatment solution is 0.6 mol / L; the temperature of the first treatment solution is 22°C; and the mass ratio of HCl to HNO3 is 1:1.

[0118] One aspect of this embodiment provides a quartz sand laser purification device, which further includes a liquid storage tank 8 located directly below one end of the frame.

[0119] Example 3:

[0120] The content that is the same as in Example 2 will not be repeated here; the differences between this embodiment and Example 2 are as follows:

[0121] One aspect of this embodiment provides a method for purifying quartz sand; the purified quartz sand contains 18 μg / g of metallic impurities; in step four, before the quartz sand undergoes secondary acid washing after laser irradiation treatment, the quartz sand is mixed with a second treatment solution, the second treatment solution comprising water and nitric acid; the hydrogen ion concentration in the second treatment solution is 0.75 mol / L; the temperature of the second treatment solution is 20°C.

[0122] The quartz sand to be purified is pre-purified; the specific process is as follows: the quartz sand to be purified is mixed with the first acid solution at a mass ratio of 5.2:1, the surface of the quartz sand is acid-washed once, and then dried after the acid wash.

[0123] The first acid solution is a mixed solution of nitric acid and hydrochloric acid, and the hydrogen ion concentration in the first acid solution is 1.75 mol / L; the mass ratio of HCl to HNO3 in the first acid solution is 1:1; the first acid washing time is 4 hours.

[0124] Then, the impurity-containing parts of the quartz sand are directionally heated by laser 2, and the laser irradiation time is 2; the output wavelength of laser 2 is 532nm and the power is 320W.

[0125] The first treatment solution includes water, nitric acid, and hydrochloric acid; the hydrogen ion concentration in the first treatment solution is 0.55 mol / L; the temperature of the first treatment solution is 25°C; and the mass ratio of HCl to HNO3 is 1:1.

[0126] After being irradiated by laser and quenched in a treatment solution, the quartz sand is mixed with a second acid solution for a second pickling process, which lasts for 7 hours.

[0127] The second acid solution is a mixed solution of nitric acid and hydrochloric acid, with a hydrogen ion concentration of 0.7 mol / L; the mass ratio of HCl to HNO3 in the second acid solution is 0.6:1.

[0128] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A method for purifying quartz sand, characterized by, The method comprises the following steps, Step one, crushing and screening the quartz sand ore to obtain quartz sand raw materials; Step two, pretreating and sorting the quartz sand raw materials to obtain quartz sand to be purified; Step three, pre-purifying the quartz sand to be purified; The pre-purification process of step three is as follows: Mix the quartz sand to be purified with the first acid solution according to a mass ratio of (4.5-5.5):1, perform one-time acid pickling on the surface of the quartz sand, and dry after one-time acid pickling; The first acid solution is a mixed solution of nitric acid and hydrochloric acid, and the hydrogen ion concentration in the first acid solution is 1.2-1.8 mol / L; the mass ratio of HCl to HNO3 in the first acid solution is 1:1; The one-time acid pickling time is 3-8 h; Step four, laser purification of the pre-purified quartz sand, the laser purification method is a laser directional gasification treatment method; the laser directional gasification treatment method in step four comprises the following steps: Directionally adjust and laser heat the pre-purified quartz sand to locally heat and treat internal impurities; The specific process is as follows: immerse the pre-purified quartz sand in the first treatment liquid, the part of the quartz sand containing impurities faces the laser, then perform directional heating on the part of the quartz sand containing impurities through the laser, and the laser irradiation time is 0.1-3 s; The first treatment liquid comprises nitric acid; the hydrogen ion concentration in the first treatment liquid is 0.5-0.8 mol / L; and the temperature of the first treatment liquid is 20-50℃; After the laser irradiation treatment of the quartz sand, mix the quartz sand with a second treatment liquid, the second treatment liquid comprises nitric acid; the hydrogen ion concentration in the second treatment liquid is 0.5-0.8 mol / L; and the temperature of the second treatment liquid is 15-25℃; Then mix the quartz sand with a second acid solution to perform two-time acid pickling, and the second-time acid pickling time is 3-8 h; The second acid solution is a mixed solution of nitric acid and hydrochloric acid, and the hydrogen ion concentration in the second acid solution is 0.5-0.8 mol / L; the mass ratio of HCl to HNO3 in the second acid solution is (0.5-0.8):1; Step five, after step four is completed, repeat the operations of steps three and four for 0-5 times; Step six, clean and dry the quartz sand after step four to obtain purified quartz sand; The content of metal impurities in the purified quartz sand is ≤25 μg / g.

2. The quartz sand purification method according to claim 1, characterized by, The specific process of step one is as follows: crush the quartz sand ore with a crushing device, screen with a 325 mesh-30 mesh screen to obtain quartz sand raw materials with a particle size of 45-550 μm.

3. The quartz sand purification method according to claim 1, characterized by, The specific process of pretreating and sorting the quartz sand raw materials in step two is as follows: Clean the quartz sand raw materials to remove surface attachments; Then, the quartz sand raw materials are subjected to magnetic separation by a magnetic separation method, and then non-magnetic mineral impurities in the quartz sand raw materials are removed by a fluorine-free flotation method.

4. The quartz sand purification method according to claim 1, characterized by, The output wavelength of the laser is 532 or 1064 nm, and the power is 60-5000 W.

5. A quartz sand laser purification apparatus, characterized by comprising: The quartz sand laser purification device realizes the quartz sand purification method of any one of claims 1-4. The quartz sand laser purification device comprises a rack, a magnetic attraction device, a laser, a spraying mechanism and a conveying purification treatment belt; the spraying mechanism comprises a plurality of nozzles; The conveying purification treatment belt is in transmission connection with the rack; The conveying purification treatment belt is provided with a plurality of baffles, and the conveying purification treatment belt is connected with side skirts on both sides; The surface of the purification treatment belt is divided into a plurality of accommodation spaces by the baffles and the side skirts, and the accommodation spaces can move along the rack; The magnetic attraction device, the laser and the nozzles are located above the conveying purification treatment belt; The light emitting ends of the magnetic attraction device and the laser are connected with the connecting plates respectively, and the light emitting end of the laser is located directly below the magnetic attraction device; The horizontal distance between the nozzles and the light emitting end of the laser is 1-20 cm.

6. The quartz sand laser purification apparatus according to claim 5, characterized by The quartz sand laser purification device further comprises a liquid storage tank, and the liquid storage tank is located directly below one end of the rack.

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