CN115870088A - Method for preparing 4N 5-grade high-purity quartz from pegmatite - Google Patents
Method for preparing 4N 5-grade high-purity quartz from pegmatite Download PDFInfo
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Abstract
The invention provides a method for preparing 4N 5-grade high-purity quartz from pegmatite, which comprises the following steps: the pegmatite is subjected to crushing, ore grinding and grading and gravity mineral separation to obtain gravity heavy mineral, gravity medium mineral and gravity light mineral, wherein the gravity light mineral is mica powder, the gravity medium mineral enters magnetic mineral separation to obtain magnetic mineral and non-magnetic mineral, the magnetic mineral and the gravity medium mineral are tailings, and large pieces of mica with the diameter of +2mm are collected in the crushing operation to be used as large mica concentrate; and carrying out flotation operation on the nonmagnetic minerals to obtain mica powder, feldspar powder and quartz rough concentrate, and carrying out calcination water quenching, ultrasonic acid leaching and heating leaching on the quartz rough concentrate to obtain the 4N 5-grade high-purity quartz. The 4N 5-grade high-purity quartz SiO prepared by the invention 2 The content can reach at least more than 99.995wt%, the content of Ti is lower than 5 mu g/g, and the content of Al is less than or equal to 20 mu g/g, thereby meeting the requirements of the quartz glass industry on high-purity quartz sand.
Description
Technical Field
The invention relates to the field of high-purity quartz preparation, in particular to a method for preparing 4N 5-grade high-purity quartz from pegmatite.
Background
High purity quartz products (especially SiO) 2 High-purity quartz products with the content of more than or equal to 99.99 percent) are mainly applied to the high-tech fields of photovoltaics, electric light sources, electronic information, optical communication and the like, and are indispensable key basic materials. At present, the preparation of high-purity quartz sand mainly comprises chemical synthesis, natural crystal processing and deep purification of natural quartz minerals. Among them, the preparation method by chemical synthesis and natural crystal processing is restricted by raw materials, cost, yield, etc., and is difficult to be applied industrially on a large scale, and the deep purification of natural quartz minerals is an effective method for preparing high-purity quartz products.
The high-purity quartz resource is a strategic non-metallic resource which is scarce in the world and is in short supply in China. China has rich quartz mineral resources, mineral places are distributed all over the country, almost all quartz industrial ore types are covered, but only part of vein quartz can be used for preparing high-purity quartz products at present. The vein quartz is mostly distributed in vein shape and chicken nest shape, the ore deposit is small in scale, the ore quality is unstable, the large-scale centralized mining cannot be realized, and the requirement of large-scale production of high-purity quartz high-end products is difficult to meet, so that the high-purity quartz resources in China almost all depend on import and mainly come from countries such as America, india and the like.
Pegmatite (Pegmatite), a pale crystalline rock composed of macroparticles of mineral, is a volatile silicate-rich slurry that slowly crystallizes upon intrusion into igneous or surrounding rock fractures. The main minerals of pegmatite are quartz, alkaline feldspar and plagioclase, muscovite or biotite, and the secondary minerals and secondary minerals include hydrous minerals, minerals containing trace elements and rare elements (Li, ti, be, la, nb, ta, W, sn, U, th, etc.), and minerals rich in F, cl, B, P, such as topaz, tourmaline, andalusite, limonite, niobite, fluorite, rutile, etc., which are not commonly found in normal igneous rocks. Pegmatite is an important source of quartz minerals, but compared with vein quartz (quartz mineral content > 90%), pegmatite generally has 20% -40% of quartz mineral content, lower quartz mineral content, more types and high content of impurity minerals, and more complicated purification process.
According to the method, a mica concentrate, a feldspar concentrate and a quartz tailing are obtained by crushing, rod grinding, magnetic separation, flotation and the like in a document (comprehensive utilization of mica granite pegmatite in West, wangfenzaman et al, non-metal ore, no. 36 of 2013 in 7 and month, no. 4), the quartz tailing is used for subsequent preparation of the quartz concentrate, but the content of mica and feldspar in the quartz tailing prepared by the method is still high, the impurity content of the quartz concentrate prepared by the quartz tailing is high, and the requirement of 4N-grade high-purity quartz is difficult to meet.
At present, a plurality of methods for purifying quartz sand exist, wherein a purification process flow of 'grinding, flotation, roasting, water quenching, hot-pressing, acid leaching' is published in patent CN111874914A, so that 4N-grade high-purity quartz sand is prepared, a leaching agent adopted in the method is sulfuric acid and hydrofluoric acid mixed acid, hot-pressing leaching is adopted for leaching, the leaching temperature is higher (220 ℃), the pressure is high during leaching, the leaching process is not easy to operate and control and the energy consumption is higher, sulfate radicals remained in the leaching process are not easy to wash and remove in the subsequent process, and the method has a limited effect of removing impurities such as iron, potassium and the like. There are also documents (study on the process of preparing high-purity quartz powder by purifying pegmatite tailings, university of Chongqing science, vol.32, 9 th period, and 9 months in 2018) that a purification process of 'grinding ore, strong magnetic separation, acid leaching, calcining water quenching, secondary acid leaching' is adopted, calcination water quenching is carried out after acid leaching, and secondary acid leaching is introduced, so that the process flow is complex. There is also a document (research on realization of quartz sand high purification by flotation-acid leaching, non-metal ore, no. 36, no. 5, 9 months in 2013) that quartz sand is purified by a simple process of "flotation-acid leaching" to obtain a high-purity quartz sand product of 99.993%, but the quartz sand product of 99.97% purity which has been subjected to beneficiation and calcination is adopted, secondary flotation is performed on the beneficiated ore, the process is more complicated, only iron and aluminum elements are partially removed in the leaching process, and potassium and sodium elements are not effectively removed.
Disclosure of Invention
The invention provides a method for preparing 4N 5-grade high-purity quartz from pegmatite, and the prepared 4N 5-grade high-purity quartz SiO 2 The content can reach at least more than 99.995wt%, the content of Ti is lower than 5 mu g/g, and the content of Al is less than or equal to 20 mu g/g, thereby meeting the requirements of the quartz glass industry on high-purity quartz sand.
The technical scheme of the invention is realized as follows: a method for preparing 4N 5-grade high-purity quartz from pegmatite comprises the following steps:
(1) The pegmatite is subjected to crushing, grinding and grading and gravity mineral separation to obtain gravity heavy minerals, gravity middlings and gravity light minerals, wherein the gravity light minerals are mica powder, the gravity middlings enter magnetic mineral separation to obtain magnetic minerals and non-magnetic minerals, and the magnetic minerals and the gravity heavy minerals are tailings;
(2) And carrying out flotation operation on the nonmagnetic minerals to obtain mica powder, feldspar powder and quartz rough concentrate, and carrying out calcination water quenching, ultrasonic acid leaching and heating leaching on the quartz rough concentrate to obtain the 4N 5-grade high-purity quartz.
Further, mineral imbedding characteristics of pegmatite: quartz, other granular structure, particle size 0.2-1cm, content 30-35%; albite, semi-self-shaped plate structure, axial length 0.5-5cm, content 40-45%; potassium feldspar, semi-self-shaped plate-shaped structure, axial length 0.5-2cm, content 15-20%; muscovite, flake shape, thick layer shape, 0.3-1cm flake diameter, 5% -10% content.
Further, in 4N5 grade high purity quartz: siO 2 2 ≥99.995wt％，Al≤20μg/g，Ti≤5μg/g。
Further, in the step (1), three-section one-closed-circuit crushing is adopted for crushing to obtain minus 2mm of undersize, and the minus 2mm of undersize is ground and classified to obtain minus 40-mesh fine minerals, and the minus 40-mesh fine minerals enter gravity separation; and collecting large mica with the diameter of +2mm in the crushing operation to be used as large mica concentrate.
Further, in the step (1), the gravity separation heavy mineral is a heavy gangue mineral containing iron and titanium, the gravity separation heavy mineral is a quartz middling, and the gravity separation light mineral is mica powder.
Further, in the step (1), the magnetic ore dressing comprises the following specific steps: performing low-intensity magnetic separation on the minerals in the reselection to obtain low-intensity magnetic tailings, and performing high-intensity magnetic separation on the low-intensity magnetic tailings for 2-3 times to obtain non-magnetic minerals, wherein the magnetic field intensity of the low-intensity magnetic separation is 1000-2000 oersted, and the magnetic field intensity of the high-intensity magnetic separation is 15000-20000 oersted.
Further, in the step (2), the specific steps of calcining and water quenching are as follows: calcining the quartz rough concentrate at high temperature, performing water quenching treatment, washing and drying after water quenching to obtain quartz concentrate; the calcining temperature is 850-950 ℃, and the calcining time is 2-4h.
Further, the specific steps of ultrasonic acid leaching are as follows: mixing the quartz concentrate subjected to water quenching with mixed acid, and performing ultrasonic-assisted leaching; the mixed acid is a combination of hydrofluoric acid and at least one of hydrochloric acid and nitric acid, the concentration of the hydrochloric acid in the mixed acid is 0.5-3mol/L, the concentration of the nitric acid is 0-1mol/L, the concentration of the hydrofluoric acid is 0.1-1.5mol/L, and the liquid-solid ratio of the mixed acid to the quartz concentrate is 1-5:1, ultrasonic-assisted leaching is carried out at room temperature, the ultrasonic power is 600-1000W, and the leaching time is 0.25-2h.
Further, in the step (2), the specific steps of heating and leaching are as follows: transferring the acid system subjected to the ultrasonic-assisted leaching to be leached at a high temperature, and washing and drying the quartz sand after the leaching is finished to prepare 4N 5-grade high-purity quartz; the leaching pressure of the high-temperature leaching is normal pressure, the leaching temperature is 30-95 ℃, and the leaching time is 2-8h.
Further, in the step (2), the specific steps of the flotation operation are as follows: the non-magnetic minerals are subjected to mica flotation to obtain mica powder and flotation tailings, and the flotation tailings are subjected to feldspar flotation to obtain feldspar powder and quartz rough concentrate.
Further, 4N 5-grade high-purity quartz is sieved and classified to obtain high-purity quartz powder and high-purity silicon micro powder.
The invention has the beneficial effects that:
the invention adopts pegmatite quartz as raw ore to prepare 4N 5-grade high-purity quartz SiO 2 The content can reach more than 99.995wt percent and even 99.996More than weight percent, less than 5 mu g/g of Ti and less than or equal to 20 mu g/g of Al, thereby meeting the requirements of the quartz glass industry on high-purity quartz sand.
(1) Compared with other quartz ores, pegmatite has high mica content and has obvious influence on impurity elements of Al and Na in a final high-purity quartz product. The preparation method of the invention collects large-scale muscovite concentrate in the ore grinding stage, separates out a part of muscovite powder through gravity separation, removes a part of biotite minerals through magnetic separation, finally detects customs through a flotation method, removes micro-fine particle mica powder, and finally is matched with the steps of calcining water quenching, ultrasonic acid leaching, heating leaching and the like, thereby ensuring that the Al content in the final high-purity quartz product is less than or equal to 20 microgram/g. Aiming at the problem that the impurity removal of mica in pegmatite is a systematic gradual process, the defects of complex flow, large medicament dosage and incomplete removal by adopting a single flotation method are avoided.
(2) The pegmatite contains a small amount of heavy minerals (e.g., rutile, iron minerals, titanium minerals, garnet, etc.) with fine grain impactions, and needs to be completely removed by a combined heavy-magnetic method. Heavy gangue minerals containing iron, titanium and the like are removed by gravity separation, strong magnetic mineral impurities such as magnetite and mechanical iron in the ore grinding process are removed by weak magnetic separation, weak magnetic minerals such as hematite, limonite, ilmenite and biotite are removed by strong magnetic separation, the impurity content in quartz rough concentrate is obviously reduced, the method has an important effect on preparing 4N 5-grade high-purity quartz, if gravity separation is not set, on one hand, some non-magnetic heavy mineral impurities such as rutile and garnet cannot be removed (the impurities cannot be separated by subsequent flotation and acid leaching), on the other hand, some micro-fine particle magnetic substances are wrapped in quartz minerals, the effect of removing by means of magnetic separation alone is limited, and the final high-purity quartz impurity content is easily caused to be overhigh;
(3) The crystal form of the quartz rough concentrate is changed in a high-temperature calcination state, so that the volume is increased, the original defect degree in the quartz crystal becomes more serious, meanwhile, mica, feldspar and other impurities mixed in the quartz rough concentrate are beneficial to acid leaching removal through high-temperature ore phase reconstruction, meanwhile, through instantaneous water quenching treatment, the crystal volume suddenly and rapidly decreases, the internal force of the crystal defect is increased, and further, the crystal is promoted to break at the defect, so that inclusions and impurities in cracks in the original quartz are exposed on the particle surface, and the acid leaching removal is easy.
(4) The calcined and water-quenched quartz concentrate is subjected to normal-temperature normal-pressure ultrasonic-assisted acid leaching under a mixed system of hydrochloric acid, nitric acid and hydrofluoric acid, so that acid can be effectively and fully contacted with quartz, the next leaching is facilitated, the leaching efficiency can be greatly improved, the acid consumption and the leaching time can be effectively reduced, and meanwhile, the acid consumption can be remarkably reduced by means of ultrasonic waves, and the contents of iron, calcium and the like in the quartz concentrate can be effectively reduced.
(5) The quartz concentrate is leached under normal pressure, the leaching temperature is low, the energy consumption is low, associated minerals such as micro-fine particle mica, feldspar and the like which are sorted and remained in quartz can be efficiently removed, and meanwhile, metal M-O bonds can be effectively broken, and metal impurities among crystal lattices can be removed.
(6) According to the invention, by means of the method settings of calcination water quenching, ultrasonic acid leaching and heating leaching, compared with other normal-temperature normal-pressure leaching methods, the method has the advantages of small leaching acid dosage, short leaching time and higher removal rate of metal elements such as iron, sodium, potassium and the like.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a process flow diagram of the method of the present invention for preparing 4N5 grade high purity quartz;
fig. 2 is a sample graph of pegmatite feedstock.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive effort based on the embodiments of the present invention, are within the scope of the present invention.
As shown in figure 1, the method for preparing 4N 5-grade high-purity quartz from pegmatite comprises the following steps:
(1) The pegmatite is subjected to crushing, grinding classification and gravity mineral separation to obtain heavy gravity minerals, medium gravity minerals and light gravity minerals, wherein the light gravity minerals are mica powder, the medium gravity minerals enter magnetic mineral separation to obtain magnetic minerals and nonmagnetic minerals, and the magnetic minerals and the heavy gravity minerals are tailings;
(2) And (3) carrying out flotation operation on the nonmagnetic minerals to obtain mica powder, feldspar powder and quartz rough concentrate, and carrying out calcination water quenching, ultrasonic acid leaching and heating leaching on the quartz rough concentrate to obtain the 4N 5-grade high-purity quartz.
The main mineral imbedding characteristics of pegmatite: quartz, other granular structure, particle size of 0.2-1cm, content of 30-35%, part of minerals and feldspar, mica, etc. are interacted to form intergrowth, and quartz partially contains mica to form inclusion structure; albite is light green and has a semi-self-shaped plate structure, the axial length is 0.5-2cm, the part is 3-5cm, the content is 40-45%, and the albite and minerals such as quartz, mica and the like form an intergrowth; potassium feldspar, white, semi-self-shaped platy structure, with axial length of 0.5-2cm and content of 15-20%, forms an intergrowth with minerals such as quartz, mica and the like; muscovite, white or light gray, sheet-like, thick layer-like, sheet diameter 0.3-1cm, content about 5%, and forms intergrowth with minerals such as quartz and feldspar, and the mica is locally contained in quartz.
In the step (1), a three-section one-closed-circuit crushing mode is adopted for crushing, the particle size of a first-section jaw-type crushing discharge material is 50mm, the particle size of a second-section long-cavity crushing discharge material is 15mm, the second-section long-cavity crushing discharge material is pre-screened after being crushed, materials with a part of-2 mm qualified size fraction are firstly separated, the phenomenon that the qualified size fraction enters a double-roller crusher again for crushing to cause over-crushing is avoided, the yield of the qualified size fraction of a high-purity quartz product can be effectively improved, the materials on the 2 mm-screened graded sieve enter the double-roller crusher for third-section crushing, the double-roller crusher and a grading device form a closed circuit, most of the materials pass through the 2mm sieve, the qualified crushed products are obtained, part of large mica can not pass through the 2mm sieve in the crushing process, and the large mica can be collected and can be used as large mica concentrate products.
In step (1), grinding classification comprises rod milling and screening classification to obtain fine ore with the size of-0.425 mm (40 meshes) and coarse ore with the size of +0.425mm, returning the coarse ore with the size of +0.425mm to the rod milling stage, and feeding the fine ore with the size of-0.425 mm to gravity ore dressing.
In the step (1), gravity concentration is carried out by adopting a shaking table, a spiral chute and the like for gravity separation, heavy minerals are heavy gangue minerals containing iron, titanium and the like, the heavy selected minerals are quartz middlings, heavy separated light minerals are mica powder, and in addition, shaking table tailings are slime generated in the ore grinding process and are discarded as tailings.
In the step (1), magnetic separation is to remove magnetic minerals in the reselection, strong magnetic minerals in the reselection such as magnetite and mechanical iron in the grinding process are removed through weak magnetic separation to obtain weak magnetic tailings, the weak magnetic tailings are subjected to strong magnetic separation for 2-3 times to remove weak magnetic minerals such as hematite, limonite, ilmenite, biotite and the like to obtain nonmagnetic minerals, the magnetic field intensity of the weak magnetic separation is 1000-2000 oersted, and the magnetic field intensity of the strong magnetic separation is 15000-20000 oersted.
In the step (2), the flotation operation comprises mica flotation and feldspar flotation, the mica flotation adopts direct flotation, the mica in the nonmagnetic minerals is separated out by the direct flotation under an acidic condition, the pH regulator for the mica flotation is sulfuric acid, the pH value of the ore pulp is regulated to 3-4, the dosage is 800-1000 g/ton, then dodecylamine is added as a collecting agent, the dosage is 50-100 g/ton, the mica flotation process structure is one-section roughing and two-section scavenging, or one-section roughing and one-section scavenging, and the dosage of scavenging agents is sequentially reduced, so that no mica continuously floats out as the operation process end point. The floated mica is further purified through blank selection to obtain mica powder product.
The tailings after mica flotation enter feldspar flotation, and feldspar flotation (or quartz reverse flotation) is carried out, wherein feldspar collecting agents are added into ore pulp with the pH value of 2-3, and the feldspar is used as a foam product to be floated. In the flotation process, sulfuric acid is used as a pH regulator, the pH value of ore pulp is regulated to 2-3, the roughing consumption is 200-500 g/ton, hydrofluoric acid is added to activate feldspar, the roughing consumption is 200-400 g/ton, then a feldspar collecting agent is added for flotation, the feldspar collecting agent is an amine cation collecting agent, anionic collecting agents such as alkyl sulfonate and the like are used for matching, the roughing consumption of the amine collecting agent is 50-100 g/ton, and the roughing consumption of the sulfonate collecting agent is 100-400 g/ton; the feldspar flotation process is long, the feldspar can be completely removed only by carrying out the flotation for 5-8 times, the dosage of the medicaments is sequentially reduced, and the foam product is subjected to blank selection to obtain the feldspar powder product.
In the step (2), the specific steps of calcining and water quenching are as follows: calcining the quartz rough concentrate at high temperature, performing water quenching treatment, washing and drying after water quenching to obtain quartz concentrate; the calcining temperature is 850-950 ℃, and the calcining time is 2-4h.
In the step (2), the ultrasonic acid leaching comprises the following specific steps: mixing the quartz concentrate subjected to water quenching treatment with mixed acid, and performing ultrasonic-assisted leaching; the mixed acid is a combination of hydrofluoric acid and at least one of hydrochloric acid and nitric acid, the concentration of the hydrochloric acid in the mixed acid is 0.5-3mol/L, the concentration of the nitric acid is 0-1mol/L, the concentration of the hydrofluoric acid is 0.1-1.5mol/L, and the liquid-solid ratio of the mixed acid to the quartz concentrate is 1-5:1, ultrasonic-assisted leaching is carried out at room temperature, the ultrasonic power is 600-1000W, and the leaching time is 0.25-2h.
In the step (2), the specific steps of heating and leaching are as follows: transferring the acid system subjected to the ultrasonic-assisted leaching to be leached at a high temperature, and washing and drying the quartz sand after the leaching is finished to prepare 4N 5-grade high-purity quartz; the leaching pressure of the high-temperature leaching is normal pressure, the leaching temperature is 30-95 ℃, and the leaching time is 2-8h.
4N 5-grade high-purity quartz is sieved and classified, the oversize product with the thickness of +0.08mm is high-purity quartz powder, and the undersize product with the thickness of-0.08 mm is high-purity silicon micropowder.
The specific embodiment is as follows:
the pegmatite raw material is a sample in a certain region in China, as shown in figure 2, the main mineral composition is shown in table 1, and the multielement analysis result is shown in table 2.
TABLE 1 pegmatite raw materials major minerals composition/%)
| Quartz | Potassium feldspar | Albite | White mica | Garnet | Limonite | Natural bismuth |
| 39.77 | 18.75 | 36.34 | 5.39 | 1.12 | 0.16 | Micro-scale |
| Iron dolomite | Kaolinite | Biotite mica | Apatite and its use | Calcite | Rutile type | Dolomite |
| 0.02 | 0.04 | 0.06 | 0.13 | 0.08 | 0.18 | Micro-scale |
| Plagioclase feldspar | Crystalline uranium ore | Zircon stone | Pyrite | |||
| 0.1 | 0.01 | 0.01 | Micro-scale |
TABLE 2 Weijing rock raw materials multielement analysis results%
| SiO 2 | Al 2 O 3 | Fe 2 O 3 | CaO | MgO | Na 2 O | K 2 O | MnO | P 2 O 3 | TiO 2 |
| 76.02 | 13.50 | 0.084 | 0.59 | 0.099 | 3.85 | 4.03 | 0.057 | 0.12 | 0.24 |
Example 1
The method for preparing the 4N 5-grade high-purity quartz from the pegmatite comprises the steps of crushing the pegmatite, grinding and grading the pegmatite, and performing gravity separation on the pegmatite to obtain a heavy selected mineral and a heavy selected light mineral, wherein the heavy selected mineral is mica powder, the heavy selected mineral enters magnetic separation, and strong magnetic mineral impurities such as magnetite and mechanical iron in the grinding process are removed through low-intensity magnetic separation to obtain low-intensity magnetic tailings, wherein the magnetic field intensity of the low-intensity magnetic separation is 1500 oersteds; removing weakly magnetic minerals such as hematite, limonite, ilmenite, biotite and the like from weakly magnetic tailings by 3 times of strong magnetic separation to obtain nonmagnetic minerals, wherein the magnetic field intensity of the strong magnetic separation is 15000 oersteds, 18000 oersteds and 20000 oersteds in sequence.
The non-magnetic minerals are subjected to mica flotation to obtain mica powder and flotation tailings, and the flotation tailings are subjected to feldspar flotation to obtain feldspar powder and quartz rough concentrate. Calcining the quartz rough concentrate in a crucible at 875 ℃ for 4h, taking out, directly pouring into ultrapure water for water quenching, washing the quartz concentrate with ultrapure water after water quenching, and drying; adding the calcined, water-quenched and dried quartz concentrate into a polytetrafluoroethylene reactor filled with mixed acid, wherein the mixed acid is mixed acid of hydrochloric acid and hydrofluoric acid, the concentration of the hydrochloric acid is 2mol/L, the concentration of the hydrofluoric acid is 1mol/L, the liquid-solid ratio of the mixed acid to the quartz concentrate is 3; and pouring the solid-liquid mixture subjected to ultrasonic-assisted leaching into a thermal reaction kettle with a polytetrafluoroethylene lining for heating leaching reaction at the leaching temperature of 95 ℃ for 3 hours. And after the leaching reaction is finished, carrying out solid-liquid separation, washing the quartz sand solid by adopting ultrapure water until no chloride ion exists, and drying to prepare the 4N 5-grade high-purity quartz.
4N 5-grade high-purity quartz is sieved and classified, oversize products with the thickness of +0.08mm are high-purity quartz powder, and undersize products with the thickness of-0.08 mm are high-purity silicon micropowder. The product index of pegmatite quartz for preparing 4N5 grade high-purity quartz is shown in Table 3.
TABLE 3 pegmatite quartz product index for preparing 4N5 grade high purity quartz
The results of ICP-MS detection of the high purity quartz are shown in Table 4.
TABLE 4N5 grade high purity quartz impurity element content (μ g/g)
| Impurity element | Al | Ca | Fe | K | Mg | Na | Ti | B |
| Element content | 19.91 | 1.37 | 1.22 | 0.92 | 0.41 | 5.35 | 4.40 | 0.78 |
| Impurity element | Cr | Cu | Li | Mn | Ni | P | Zr | |
| Content of elements | 0.014 | 0.014 | 0.91 | 0.025 | 0.046 | 0.023 | 0.062 |
As can be seen from Table 4, siO of the 4N5 grade high purity quartz sand prepared in the examples of the invention 2 The content can reach 99.9964wt%, and the high-purity quartz sand prepared by the method has the Ti content lower than 5 mu g/g and the Al content lower than 20 mu g/g can meet the requirement of the industry on the high-purity quartz sand.
Example 2
This embodiment is substantially the same as embodiment 1 except that: the magnetic field intensity of the low-intensity magnetic separation is 2000 oersted, the high-intensity magnetic separation is adopted for 2 times, and the magnetic field intensity is 15000 oersted and 20000 oersted.
In the step (2), the specific steps of calcining and water quenching are as follows: calcining the quartz rough concentrate at high temperature, performing water quenching treatment, washing and drying after water quenching to obtain quartz concentrate; the calcining temperature is 850 ℃, and the calcining time is 4h.
In the step (2), the ultrasonic acid leaching comprises the following specific steps: mixing the quartz concentrate subjected to water quenching with mixed acid, and performing ultrasonic-assisted leaching; the concentration of hydrochloric acid in the mixed acid is 0.5mol/L, the concentration of nitric acid is 1mol/L, the concentration of hydrofluoric acid is 1.5mol/L, and the liquid-solid ratio of the mixed acid to the quartz concentrate is 5:1, carrying out ultrasonic-assisted leaching at room temperature, wherein the ultrasonic power is 1000W, and the leaching time is 0.25h.
In the step (2), the specific steps of heating and leaching are as follows: transferring the acid system subjected to the ultrasonic-assisted leaching to be leached at a high temperature, and washing and drying the quartz sand after the leaching is finished to prepare 4N 5-grade high-purity quartz; the leaching pressure of the high-temperature leaching is normal pressure, the leaching temperature is 30 ℃, and the leaching time is 8 hours.
Example 3
This embodiment is substantially the same as embodiment 1 except that: in the step (2), the specific steps of calcining and water quenching are as follows: calcining the quartz rough concentrate at high temperature, performing water quenching treatment, washing and drying after water quenching to obtain quartz concentrate; the calcining temperature is 950 ℃, and the calcining time is 2h.
In the step (2), the ultrasonic acid leaching comprises the following specific steps: mixing the quartz concentrate subjected to water quenching with mixed acid, and performing ultrasonic-assisted leaching; the concentration of hydrochloric acid in the mixed acid is 3mol/L, the concentration of nitric acid is 0.5mol/L, the concentration of hydrofluoric acid is 0.1mol/L, and the liquid-solid ratio of the mixed acid to the quartz concentrate is 1:1, carrying out ultrasonic-assisted leaching at room temperature, wherein the ultrasonic power is 600W, and the leaching time is 2h.
In the step (2), the specific steps of heating and leaching are as follows: transferring the acid system after the ultrasonic-assisted leaching to leaching at high temperature, and washing and drying the quartz sand after the leaching is finished to prepare 4N 5-grade high-purity quartz; the leaching pressure of the high-temperature leaching is normal pressure, the leaching temperature is 60 ℃, and the leaching time is 5 hours.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and should not be taken as limiting the scope of the present invention, which is intended to cover any modifications, equivalents, improvements, etc. within the spirit and scope of the present invention.
Claims (10)
1. The method for preparing 4N 5-grade high-purity quartz from pegmatite is characterized by comprising the following steps of:
(1) The pegmatite is subjected to crushing, grinding and grading and gravity mineral separation to obtain gravity heavy minerals, gravity middlings and gravity light minerals, wherein the gravity light minerals are mica powder, the gravity middlings enter magnetic mineral separation to obtain magnetic minerals and non-magnetic minerals, and the magnetic minerals and the gravity heavy minerals are tailings;
(2) And (3) carrying out flotation operation on the nonmagnetic minerals to obtain mica powder, feldspar powder and quartz rough concentrate, and carrying out calcination water quenching, ultrasonic acid leaching and heating leaching on the quartz rough concentrate to obtain the 4N 5-grade high-purity quartz.
2. The method for preparing high-purity quartz grade 4N5 from pegmatite according to claim 1, wherein the mineral embedding characteristics of pegmatite are as follows: quartz, other granular structure, particle size 0.2-1cm, content 30-35%; albite, semi-self-shaped plate structure, axial length 0.5-5cm, content 40-45%; potassium feldspar, semi-self-shaped plate structure, axial length 0.5-2cm, content 15-20%; muscovite, flake and thick layer, with a diameter of 0.3-1cm and a content of 5% -10%.
3. The method for preparing high-purity quartz grade 4N5 from pegmatite according to claim 1 or 2, wherein in the high-purity quartz grade 4N 5: siO 2 2 ≥99.995wt％，Al≤20μg/g，Ti≤5μg/g。
4. The method for preparing high-purity quartz of grade 4N5 from pegmatite according to claim 1, wherein the method comprises the following steps: in the step (1), three-section one-closed-circuit crushing is adopted for crushing to obtain minus 2mm undersize products, and the minus 2mm undersize products are ground and classified to obtain minus 40-mesh fine minerals, and the minus 40-mesh fine minerals enter gravity separation; and collecting large mica with the diameter of +2mm in the crushing operation to be used as large mica concentrate.
5. The method for preparing high-purity quartz of grade 4N5 from pegmatite according to claim 1, wherein the method comprises the following steps: in the step (1), the gravity separation heavy mineral is a heavy gangue mineral containing iron and titanium, the gravity separation heavy mineral is quartz middling, the gravity separation light mineral is mica powder, and gravity separation tailings are obtained and are slime produced in the ore grinding process and are discarded as tailings.
6. The method for preparing high-purity quartz of grade 4N5 from pegmatite according to claim 1, wherein the method comprises the following steps: in the step (1), the magnetic ore dressing specifically comprises the following steps: performing low-intensity magnetic separation on the minerals in the reselection to obtain low-intensity magnetic tailings, and performing high-intensity magnetic separation on the low-intensity magnetic tailings for 2-3 times to obtain non-magnetic minerals, wherein the magnetic field intensity of the low-intensity magnetic separation is 1000-2000 oersted, and the magnetic field intensity of the high-intensity magnetic separation is 15000-20000 oersted.
7. The method for preparing high-purity quartz grade 4N5 from pegmatite as claimed in claim 1, wherein: in the step (2), the specific steps of calcining and water quenching are as follows: calcining the quartz rough concentrate at high temperature, performing water quenching treatment, washing and drying after water quenching to obtain quartz concentrate; the calcining temperature is 850-950 ℃, and the calcining time is 2-4h.
8. The method for preparing high-purity quartz of grade 4N5 from pegmatite according to claim 7, wherein the method comprises the following steps: the ultrasonic acid leaching comprises the following specific steps: mixing the quartz concentrate subjected to water quenching with mixed acid, and performing ultrasonic-assisted leaching; the mixed acid is a combination of hydrofluoric acid and at least one of hydrochloric acid and nitric acid, the concentration of the hydrochloric acid in the mixed acid is 0.5-3mol/L, the concentration of the nitric acid is 0-1mol/L, the concentration of the hydrofluoric acid is 0.1-1.5mol/L, and the liquid-solid ratio of the mixed acid to the quartz concentrate is 1-5:1, carrying out ultrasonic-assisted leaching at room temperature, wherein the ultrasonic power is 600-1000W, and the leaching time is 0.25-2h.
9. The method for preparing high-purity quartz of grade 4N5 from pegmatite according to claim 8, wherein the method comprises the following steps: in the step (2), the specific steps of heating and leaching are as follows: transferring the acid system subjected to the ultrasonic-assisted leaching to be leached at a high temperature, and washing and drying the quartz sand after the leaching is finished to prepare 4N 5-grade high-purity quartz; the leaching pressure of the high-temperature leaching is normal pressure, the leaching temperature is 30-95 ℃, and the leaching time is 2-8h.
10. The method for preparing high-purity quartz of grade 4N5 from pegmatite according to claim 1, wherein the method comprises the following steps: and 4N 5-grade high-purity quartz is sieved and classified to obtain high-purity quartz powder and high-purity silicon micro powder.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117258995A (en) * | 2023-09-19 | 2023-12-22 | 安徽省地质实验研究所(国土资源部合肥矿产资源监督检测中心) | Method for extracting low-iron high-purity quartz and feldspar from granite pegmatite mineral dressing tailings |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117258995A (en) * | 2023-09-19 | 2023-12-22 | 安徽省地质实验研究所(国土资源部合肥矿产资源监督检测中心) | Method for extracting low-iron high-purity quartz and feldspar from granite pegmatite mineral dressing tailings |
| CN117258995B (en) * | 2023-09-19 | 2024-03-22 | 安徽省地质实验研究所(国土资源部合肥矿产资源监督检测中心) | Method for extracting low-iron high-purity quartz and feldspar from granite pegmatite mineral dressing tailings |
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