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A purification process including flotation separation, acid leaching, calcination, and water quenching was conducted to obtain high-purity quartz sand. The surface morphology of the quartz after flotation separation, acid leaching, calcination, and water quenching reveals that the cracks, pits, and cavities on the quartz surface can be deepened and enlarged, and the more fluid inclusions, the greater the number and openness of cracks, pits, and cavities. The specific surface area is positively correlated with the number of cracks, pits, and cavities, the opacity of quartz glass, and the number of bubbles in quartz glass. The results of Raman spectroscopy analysis reveal that the bubbles in quartz glass are composed of nitrogen, which excludes the possibility of bubble formation in quartz glass caused by the gas composition (i.e., H2O) of unburst fluid inclusions in quartz sand. The formation of bubbles in quartz glass is more likely to be related to a high specific surface area and porosity, which increase the surface adsorption performance of quartz and contribute to the adsorption of more gas. The presented results suggest that using these methods to reduce the content of fluid inclusions in quartz cannot effectively solve the problem of bubbles in quartz glass, and using quartz raw materials with no or minor fluid inclusions is still the key to ensuring the quality of quartz products. [ABSTRACT FROM AUTHOR]

Abstract\nKEY POINTSHigh-purity quartz (HPQ) is the only naturally occurring and economically viable source for the production of silicon. Silicon is a critical mineral, and a key component in modern technologies such as semiconductors and photovoltaic cells. Critical minerals support the move towards a greater reliance on electrification, renewable energy sources and economic security. The global transition to net zero carbon emissions means there is a growing need for new discoveries of HPQ to supply the silicon production chain. HPQ deposits are identified in a multitude of geological settings, including pegmatites, hydrothermal veins, sedimentary accumulations and quartzite; however, deposits of sufficient volume and quality are rare. Quartz is abundant throughout Australia, but the exploration and discovery of HPQ occurrences are notably under-reported, making assessment of the HPQ potential in Australia extremely difficult. This paper presents a much-needed summary of the state of the HPQ industry, exploration and deposit styles in Australia.High-purity quartz (HPQ) is a key material for the manufacture of photovoltaic cells, semiconductors and other high-technology applications.HPQ can be recovered from a variety of different source rocks in a range of geological settings.Currently, the HPQ industry in Australia is under-utilised for high-technology applications, and historical exploration and mining records are under-reported and opaque.This review presents an outline of the characteristics, processing requirements and end uses of HPQ, and a summary of the operations, deposits, exploration targets and known occurrences of HPQ in Australia. [ABSTRACT FROM AUTHOR]

This study focuses on the purification and evaluation of the high-purity quartz (HPQ) potential of vein quartz ore from Pakistan. Vein quartz is grayish-white and translucent, with its mineral composition mainly comprising quartz crystal. Processed quartz sand is obtained from quartz raw ore through purifying technologies, including crushing, ultrasonic desliming, flotation, high-temperature calcination, water quenching, hot pressure acid leaching, and chlorination roasting. The microscopic characteristics show that the vein quartz raw ore has a medium-coarse granular metacrystalline structure, high quartz content, with only a small quantity of fine-grained K-feldspar. The inclusions primarily consist of large-sized primary inclusions and secondary fluid inclusions developed along the micro-fractures, and the content of inclusions in most areas of the crystal is very low or even nonexistent. The quartz ore with such inclusion characteristics is considered a relatively good raw material for quartz. Component analysis shows that the main impurity elements in the quartz ore are Al, K, Ca, Na, Ti, Fe, and Li, with a total impurity element content of 128.86 µg·g−1. After purification, only lattice impurity elements Al, Ti, and Li remain in the processed quartz sand, resulting in a total impurity element content of 24.23 µg·g−1, an impurity removal rate of 81.20%, and the purity of SiO2 reaching 99.998 wt.%. It is suggested that when the quartz raw ore contains high content of lattice impurity elements, such as Al, Li, and Ti, it is difficult to remove them by the current purification method. In industrial production, considering the economic cost, if quartz sand still contains high content of lattice impurity elements Al, Ti, and Li after flotation, it cannot be used as a raw material for high-end HPQ. [ABSTRACT FROM AUTHOR]

While numerous studies have explored the mineralogical characteristics and purification techniques of high-purity quartz (HPQ), discussions on impurity control during various purification processes and their applications in photovoltaics, electronics, and optics remain limited. This review delves into the adverse effects of impurities such as aluminum, iron, and sodium in the manufacturing processes of these industries, emphasizing their critical role as these impurities can degrade material performance. This paper focuses on analyzing the types of impurities found in quartz and evaluates existing purification technologies such as acid washing, ultrasonic acid washing, chlorination roasting, and calcination quenching. It highlights the limitations of current technologies in processing quartz ore and discusses the advantages of different impurity types under various technological treatments. Moreover, it explores the environmental and economic impacts of these high-purity processes, underlining the necessity for more environmentally friendly and cost-effective purification techniques. The purpose of this review is to provide a comprehensive technical and strategic framework for the use of high-purity quartz in high-tech applications, supporting future research and industrial applications in this critical material field. [ABSTRACT FROM AUTHOR]

A purification process including flotation separation, acid leaching, calcination, and water quenching was conducted to obtain high-purity quartz sand. The surface morphology of the quartz after flotation separation, acid leaching, calcination, and water quenching reveals that the cracks, pits, and cavities on the quartz surface can be deepened and enlarged, and the more fluid inclusions, the greater the number and openness of cracks, pits, and cavities. The specific surface area is positively correlated with the number of cracks, pits, and cavities, the opacity of quartz glass, and the number of bubbles in quartz glass. The results of Raman spectroscopy analysis reveal that the bubbles in quartz glass are composed of nitrogen, which excludes the possibility of bubble formation in quartz glass caused by the gas composition (i.e., H2O) of unburst fluid inclusions in quartz sand. The formation of bubbles in quartz glass is more likely to be related to a high specific surface area and porosity, which increase the surface adsorption performance of quartz and contribute to the adsorption of more gas. The presented results suggest that using these methods to reduce the content of fluid inclusions in quartz cannot effectively solve the problem of bubbles in quartz glass, and using quartz raw materials with no or minor fluid inclusions is still the key to ensuring the quality of quartz products.

This study focuses on the purification and evaluation of the high-purity quartz (HPQ) potential of vein quartz ore from Pakistan. Vein quartz is grayish-white and translucent, with its mineral composition mainly comprising quartz crystal. Processed quartz sand is obtained from quartz raw ore through purifying technologies, including crushing, ultrasonic desliming, flotation, high-temperature calcination, water quenching, hot pressure acid leaching, and chlorination roasting. The microscopic characteristics show that the vein quartz raw ore has a medium-coarse granular metacrystalline structure, high quartz content, with only a small quantity of fine-grained K-feldspar. The inclusions primarily consist of large-sized primary inclusions and secondary fluid inclusions developed along the micro-fractures, and the content of inclusions in most areas of the crystal is very low or even nonexistent. The quartz ore with such inclusion characteristics is considered a relatively good raw material for quartz. Component analysis shows that the main impurity elements in the quartz ore are Al, K, Ca, Na, Ti, Fe, and Li, with a total impurity element content of 128.86 µg·g−1. After purification, only lattice impurity elements Al, Ti, and Li remain in the processed quartz sand, resulting in a total impurity element content of 24.23 µg·g−1, an impurity removal rate of 81.20%, and the purity of SiO2 reaching 99.998 wt.%. It is suggested that when the quartz raw ore contains high content of lattice impurity elements, such as Al, Li, and Ti, it is difficult to remove them by the current purification method. In industrial production, considering the economic cost, if quartz sand still contains high content of lattice impurity elements Al, Ti, and Li after flotation, it cannot be used as a raw material for high-end HPQ.

Quartz deposits are widely dispersed in nature, but the presence of ore bodies capable of yielding high-purity quartz is exceedingly rare. As a result, the effective purification and processing of high-purity quartz from natural siliceous materials has emerged as a prominent area of research within the non-metallic mineral processing field. This article offers an overview of the current state of research and its limitations in quartz purification and processing technology in China, including the characteristics of quartz mineral resources, the geological origins of ore deposits, impurity forms in ores, and purification techniques. Drawing from examples of five distinct types of quartz ores—vein quartz, powder quartz, quartzite, granitic pegmatite, and pegmatitic granite—we delve into the inherent properties of quartz deposits, ores, and minerals from a mineralogical perspective, establishing their link to purification and processing methodologies. A fundamental challenge restraining the advancement of the high-purity quartz industry is the absence of criteria for evaluating and selecting high-purity quartz raw materials. Existing purification technologies grapple with issues such as intricate single mineral liberation, substantial acid consumption, high energy requirements, and protracted processing procedures. The lack of mineralogically based deep purification techniques presents a hurdle to the development of the high-purity quartz industry. Given the diversity of ore types, the pursuit of knowledge-driven design and the development of economically efficient, environmentally friendly, and streamlined new technologies for tackling the complexities of the purification process may constitute the future direction of our endeavors. [ABSTRACT FROM AUTHOR]

While numerous studies have explored the mineralogical characteristics and purification techniques of high-purity quartz (HPQ), discussions on impurity control during various purification processes and their applications in photovoltaics, electronics, and optics remain limited. This review delves into the adverse effects of impurities such as aluminum, iron, and sodium in the manufacturing processes of these industries, emphasizing their critical role as these impurities can degrade material performance. This paper focuses on analyzing the types of impurities found in quartz and evaluates existing purification technologies such as acid washing, ultrasonic acid washing, chlorination roasting, and calcination quenching. It highlights the limitations of current technologies in processing quartz ore and discusses the advantages of different impurity types under various technological treatments. Moreover, it explores the environmental and economic impacts of these high-purity processes, underlining the necessity for more environmentally friendly and cost-effective purification techniques. The purpose of this review is to provide a comprehensive technical and strategic framework for the use of high-purity quartz in high-tech applications, supporting future research and industrial applications in this critical material field.

This is an article in the field of process mineralogy. As the raw material of high-grade quartz products，higher-purity quartz sand has strict requirements on impurity elements．Besides that，the presence of inclusions has an important impact on its purity and performance．Based on this，the fluid inclusions in the vein quartz of western Hubei Province have been studied in detail by using X-ray diffraction，plasma atomic emission spectroscopy，optical microscope，micro temperature measurement and laser Raman spectroscopy．The results show that the content of SiO2 in the ore is beyond 99.9%，and the impurity elements are mainly Al and alkali metal elements．The inclusions in the quartz are single-phase saline solution inclusions，two-phase inclusions and containing CO2 three-phase inclusions．There is no solid inclusions in the ore．The size of inclusions is mainly concentrated in 5～25 μm．The uniform temperature is 160～270 ℃ and the salinity is less than 10.00% NaCl. As a result, the ore-forming fluid belongs to medium-low temperature and low salinity fluid.According to the analysis results of the inclusion characteristics, the ore can be used as a raw material for high-purity quartz sand after deep processing and purification．

Iron is one of the most stubborn impurities in quartz minerals, and the iron content partly determines the various applications of quartz. Iron can exist in quartz in the forms of iron minerals, fluid inclusions, and lattice impurities. The removal of iron and the consequent purification of quartz minerals are the key processes to obtaining high-quality quartz. Iron removal methods including conventional pre-treatment, magnetic separation, acid leaching, microbiological, roasting, and flotation, as well as combined iron removal methods in quartz ore, are herein summarized. The separation mechanism of quartz and iron impurities and the latest research progress were explained and summarized, and the development prospects of quartz purification in the future were proposed based on the current progress and limitations of quartz iron removal. [ABSTRACT FROM AUTHOR]

Copyright of Industrial Minerals & Processing / Huagong Kuangwu yu Jiagong is the property of Industrial Minerals & Processing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Impurity minerals, as one of the main occurrence states of impurity elements in high-purity quartz, are strictly limited components in high-purity quartz sand products, and are also the key factors affecting the purification plan of high-purity quartz. Therefore, accurate analysis and determination of the composition, content and occurrence characteristics of impurity minerals in high-purity quartz are important references for the quality evaluation, raw material selection and purification scheme formulation of high-purity quartz sand products. In this study, a method was developed to determine impurity minerals in high-purity quartz sand products with SiO2 contents greater than 99. 998% (4N8) by the Automated Process Mineralogy Analyzing System (BPMA) with version 2.0 BPMA software, which was based on scanning electron microscope (SEM) equipped with energy dispersive X-ray spectrometer (EDS). The results showed that the content of quartz was 99. 9988%, the data were well agreed with the quality indicators by chemical analysis of high-purity quartz products. The impurity minerals were mainly augite {Ca(Mg, Fe, Al)[(Si, Al)2O6]} and zircon [Zr(SiO4)], and an extremely small amount of calcite [(Ca(CO3)], xenotime-(Y) [ Y (PO4)], monazite-(Ce) [(Ce, La, Nd) (PO4)] and galena (PbS) was detected. The particle size of quartz in the high-purity quartz sand products was relatively uniform, major among 0. 020--0. 208 mm. The size of impurity minerals was very fine, and the grain size of impurities was less than 43 µM, mainly embedded in quartz in the form of fine-grained mineral inclusions. In conclusion, the method is accurate, reliable, simple and efficient, which is suitable for the analysis and determination of the composition, content and occurrence characteristics of impurity minerals in high-purity quartz. It can also provide technical reference for the determination of trace impurities in other high-purity materials. [ABSTRACT FROM AUTHOR]

Purpose. This research aims to characterize the Langkat quartz mineral, especially its impurities, and to study the effectiveness of fungal-based leaching methods to purify the mineral in order to improve the quartz quality for high-tech industrial applications. Methods. Quartz was firstly analyzed to identify the mineral and chemical impurities. Quartz purification and beneficiation was performed by direct bioleaching using live indigenous Aspergillus niger, indirect bioleaching using metabolic lixiviant of the fungus, and chemical leaching using analytical grade oxalic acid. Findings. The mineral composition of the Langkat quartz deposit is dominated by quartz mineral (93%) with minor amounts of orthoclase feldspar (KAlSi3O8, 5%) and calcite (CaCO3, 2%). The chemical composition comprises 98.1% SiO2 with metal impurities of 0.8% Fe2O3, 0.29% Al2O3, 0.03% NiO, 0.028% Cr2O3 and 0.063% CuO, indicating that quartz is still not enough for advanced material production industry. The bioleaching process removes up to 98% of iron (Fe2O3) from the original quartz sample, and completely removes other metals within eight days of the process by direct bioleaching and eight hours by indirect bioleaching. The content of Fe2O3 and other metals in the treated quartz meets the specifications of high purity quartz (≤ 0.05%) for advanced material production industry. Meanwhile, chemical leaching using 0.2 M oxalic acid removes 96.9% of iron and 92.8% of aluminium. Originality. Comparison of the bioleaching potential of present indigenous Aspergillus niger with some of the previous studies shows that this strain has a higher ability to remove metal impurities from quartz in a much shorter processing time (8 hours instead of weeks or months) than most of the previously published microorganisms. Practical implications. The experimental result of this research provides significant potential for using a fungus-based purification approach to obtain high-purity quartz to be used in a high-value-added modern commercial product. [ABSTRACT FROM AUTHOR]

The relevance of the study is caused by the study and involvement of quartz-vein formations of various genetic types in the technological redistribution. Purpose: to determine the content of impurity elements in quartz of different genetic types and the degree of its suitability for obtaining high-purity quartz concentrates. Objects: quartz-vein objects of hydrothermal-metamorphogenic-metasomatic type (Berkutinskaya vein, Bolotnaya vein) and hydrothermal-metamorphogenic type (Peschanoe occurrence, Tolstikha vein, Novotroitskoe deposit). Methods: LA-ICP-MS spectroscopy of impurity elements, microscopic studies of quartz, estimation of P-T parameters of mineral formation. Results. It was found that veins of hydrothermal-metamorphogenic-metasomatic type are composed of multi-grained granular transparent, translucent, icy, sugar-like quartz, while quartz-vein objects of hydrothermal-metamorphogenic type are veins of execution and consist mainly of milky-white quartz. Quartz-vein formations of two genetic types differ in geological localization conditions, mineral formation temperatures, granulometric characteristics, the presence and location of mineral and fluid inclusions, as well as the content of the main petrogenetically informative elements-impurities (Li, Na, Mg, Al, K, Ti, Cr, Mn, Fe, Ni, Cu, Zn). It is shown that hydrothermal-metamorphogenic quartz is characterized by lower (288–410 °C) formation temperatures compared to hydrothermal-metamorphogenic-metasomatic quartz (415–519 °C), at close pressure values (2–4 kbar) and higher content of impurity elements (up to 535 g/t). The purity of quartz grains of hydrothermal-metamorphogenic-metasomatic genesis is associated with repeated exposure to the processes of metamorphism and metasomatosis, in which mineral and fluid inclusions were displaced from quartz grains into the intergranular space. The minimum values of the element content according to LA-ICP-MS spectroscopy are close to the values for the content of elements in the structural form and do not exceed 5–12 g/t for all types of quartz, with the exception of milky-white quartz of Peschanoe occurrence (up to 25 g/t). The minimum values for the content of elements-impurities in quartz show the limit of its enrichment and allow using a multi-stage enrichment system to obtain quartz concentrates of high purity.

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

High-purity quartz, famous for low impurities and high purity, has been widely used in optical fiber communication, photovoltaic, aerospace, semiconductor displayand other high-tech industries. Aluminosilicate mineral is one of the most typical gangue minerals in quartz ore, mainly including potassium, albite, mica, etc. With the existing conventional separation process, it is difficult to effectively and efficiently remove these intractable trace and micro-fine feldspar and mica. In this paper, the basic status of separation of aluminosilicate gangue minerals from high-purity quartz is described in detail, and the frontier technology of activation and separation of refractory trace and micro-fine feldspar and mica is systematically summarized. Based on the research progress of the basic theory of high-purity quartz in China in recent years, some reasonable scientific suggestions are put forward for the separation of micro-and micro-fine aluminosilicate gangue minerals in the crystal interface and inner encapsulation of high-quality quartz.

High-purity quartz, famous for low impurities and high purity, has been widely used in optical fiber communication, photovoltaic, aerospace, semiconductor display and other high-tech industries. The trace metal and nonmetallic elements (H, Li, B, Na, Al, P, K, Ca, Fe, Ti, etc.) widely occurring in quartz crystal structure are closely bound by Si-O-Si bond, which is difficult to be separated by conventional mineral processing technology. In this paper, the occurrence mechanism of trace elements bound by lattice in high-purity quartz is described in detail, and the advanced separation technology of trace elements in the crystal structure of high-quality quartz in the world is comprehensively and systematically summarized. Based on the research progress of the basic theory of high-purity quartz in China in recent years, some reasonable scientific suggestions on the basic theory of impurity separation of high-purity quartz lattice in China are put forward.

High-purity quartz, famous for low impurities and high purity, has been widely used in optical fiber communication, photovoltaic, aerospace, semiconductor display and other high-tech industries. Fluid inclusions, either derived from primary ore-forming fluids or captured by quartz in late geological actions, are typical fluid impurities in crystal quartz. In particular, some small gas and liquid inclusions encapsulated in quartz crystals are difficult to be separated effectively by conventional mineral processing techniques. In this paper, the basic characteristics of fluid inclusions in high purity quartz are described in detail, and the current status of fluid inclusions activation and separation technology is summarized. Based on the research progress of the basic theory of high-purity quartz in China in recent years, some scientific suggestions on the basic theory of high-purity quartz in China are put forward.

High-purity quartz (HPQ) is an important material widely used in many high-tech industries. It is a product processed from pure natural quartz raw materials, so selecting suitable quartz raw material is the key to successfully processing HPQ. Hydrothermal quartz vein is one of the most likely raw materials to be purified into HPQ because of its high SiO2 content. This study focuses on the evaluation of HPQ raw material potential of the two gold-bearing quartz vein tailing resources in Chibougamau (CBG) and Tianjingshan (TJS). Petrography and the contents of impurity elements in the two vein quartz samples before and after processing were studied by optical microscope, SEM, Raman spectrometry, XRD, LA-ICP-MS, and bulk solution ICP-OES. Petrographic results reveal that major impurities in quartz are feldspar, mica, iron compounds, ankerite, rutile, silicate melt, and fluid inclusions. LA-ICP-MS analysis result shows that the SiO2 contents are between 99.953–99.971 wt.% in CBG raw quartz and 99.969–99.976 wt.% in TJS raw quartz, respectively, with very low contents of impurity elements, except for Ca. Bulk solution ICP-OES analysis demonstrates that the CBG processed quartz sand has total impurity contents of 56.8 µg·g−1, with 13.1 µg·g−1 Al and 6.6 µg·g−1 Ti, and the TJS processed quartz sand has the total impurity contents of 85.2 µg·g−1 with 29.4 µg·g−1 Al and 6.1 µg·g−1 Ti. Both the contents of Al and Ti fit with the lattice-bound criteria for HPQ. These results, for most of the impurities, are likely hosted by silicate melt, fluid, and mineral inclusions, indicating that these two hydrothermal raw vein quartz samples can be upgraded to HPQ after processing by more advanced methods. Therefore, the CBG and TJS quartz vein deposits would be considered as potential future resources for HPQ to realize efficient recovery and utilization of tailings resources and to improve mine economic benefits. [ABSTRACT FROM AUTHOR]

High-silicon iron ore tailing is typically regarded as abundant mining waste of little use; it occupies a vast area of land and is harmful to human health and the ecological environment. Nevertheless, high-silicon iron ore tailing contains abundant quartz resource. In this study, a superconducting high gradient magnetic separation (S-HGMS) coupling fluorine-free mixed acid leaching technology was used to prepare high-purity quartz from high-silicon iron ore tailing. The S-HGMS technology was applied to separate and extract quartz from high-silicon iron ore tailing. Subsequently, the obtained quartz concentrate was subjected to an acid mixture leaching procedure to extract its impurities and obtain high-purity quartz. The optimal conditions determined for the magnetic separation process were a solid concentration of 4% and slurry flow velocity of 0.12 m/s. Under these conditions, the SiO 2 grade of the quartz concentrate reached 98.56 ± 0.13%, and the SiO 2 recovery was 60.59 ± 0.13%. The optimal conditions of the leaching process were a solid–liquid ratio of 1:4, leaching temperature of 80 °C, reaction time of 10 h, and acid mixture of HNO 3 , HCl, and H 2 SO 4 (molarity ratio of 1:4:1). Under these conditions, the SiO 2 purity reached a maximum value of 99.92 ± 0.01% in the high-purity quartz. Furthermore, we proposed a process for evaluating the recovery potential of Fe from iron-rich substances and recycling the leaching solution. The applied technology achieved a comprehensive utilization of high-silicon iron ore tailing and no waste discharge, meanwhile provides a theoretical basis and data support for its industrialization. [ABSTRACT FROM AUTHOR]

Quartz deposits are widely dispersed in nature, but the presence of ore bodies capable of yielding high-purity quartz is exceedingly rare. As a result, the effective purification and processing of high-purity quartz from natural siliceous materials has emerged as a prominent area of research within the non-metallic mineral processing field. This article offers an overview of the current state of research and its limitations in quartz purification and processing technology in China, including the characteristics of quartz mineral resources, the geological origins of ore deposits, impurity forms in ores, and purification techniques. Drawing from examples of five distinct types of quartz ores—vein quartz, powder quartz, quartzite, granitic pegmatite, and pegmatitic granite—we delve into the inherent properties of quartz deposits, ores, and minerals from a mineralogical perspective, establishing their link to purification and processing methodologies. A fundamental challenge restraining the advancement of the high-purity quartz industry is the absence of criteria for evaluating and selecting high-purity quartz raw materials. Existing purification technologies grapple with issues such as intricate single mineral liberation, substantial acid consumption, high energy requirements, and protracted processing procedures. The lack of mineralogically based deep purification techniques presents a hurdle to the development of the high-purity quartz industry. Given the diversity of ore types, the pursuit of knowledge-driven design and the development of economically efficient, environmentally friendly, and streamlined new technologies for tackling the complexities of the purification process may constitute the future direction of our endeavors.

As an important new non-metallic electronic material，higher-purity quartz sand has high requirements on impurity elements in inclusions of raw materials．Besides that ，the presence of inclusions has an important impact on its purity and performance．Based on this，the fluid inclusions in the vein quartz abroad have been studied in detail by using optical microscope, X-ray diffraction，plasma atomic emission spectroscopy，micro temperature measurement and laser Raman spectroscopy．The results show that the content of SiO2 in the ore is beyond 99.9%，and the impurity elements are mainly Al，alkali metal elements and Fe．The inclusions in the quartz are single-phase saline solution inclusions，two-phase saline solution inclusions and containing CO2 three-phase inclusions．There is no solid inclusions in the ore．The uniform temperatures of the two samples inclusions are 120～270℃ and 90～140℃．As a result，the deposit of the ore is medium-low temperature hydrothermal metamorphic quartzite．The raw ore can be used as the raw material of higher purity quartz sand after inclusion elimination and impurity reduction.

Prepare of high-purity quartz using vein quartz by alkali corrosion and acid leaching processes was investigated in this study. Using alkali corrosion method, the impurities on the surface of quartz particles can be removed and the cracks on the quartz surface can be deepened and enlarged, accompanied by the existence of corrosion pits, which is conducive to the acid leaching into the particles and the reaction with the internal impurities during further acid leaching. After leaching by acid solution, the impurity present in the vein quartz can be leached into the solution and high-purity quartz can be obtained. Influence of NaOH concentration, reaction temperature and reaction time affecting on removal rate of impurity element Fe, Al, k, Na and Li and in the alkali corrosion process were studied to obtain the optimum condition. Maximum removal rate of Fe (65.84%), K (50.26%), Na (55.96%), Li (20%),, Al(17.12%) can be obtained at the condition: NaOH concentration 12%, 200 °C temperature and 100 min of reaction time. After acid leaching using 4 mol/L HCl、1 mol/L HNO3、0.25 mol/L HF at 200 °C for 5 h, the high-purity quartz (99.994%) can be obtained eventually. [ABSTRACT FROM AUTHOR]

As one of the strategic mineral material, high-purity quartz has been widely used in integrated circuits, semiconductor chips, solar energy and other high-tech industries. However, raw material deposits that can be used to produce high-purity quartz are extremely scarce, especially in China. Southeastern Hubei is the main distribution area of vein quartz deposits in Hubei Province. In this paper, the gangue mineral types and inclusion characteristics of vein quartz from the Fujiashan quartz deposit in southeastern Hubei are observed by optical microscope and scanning electron microscope. The trace element concentrations of the raw quartz material are analyzed by inductively coupled plasma atomic emission spectrometry (ICP-OES) to obtain the impurity element characteristics of Fujiashan quartz deposit and evaluate the potential of the deposit as a raw material for high-purity quartz. The results show that the average content of SiO2 of the raw quartz is more than 99. 95%, and the impurity elements( Al, K, Fe, Ti, Ca, etc. ) mainly occur in gangue minerals such as muscovite, potassium feldspar and iron oxide, lattice-bound form and fluid inclusions. The results show that the quality of Fujiashan quartz raw ore reaches the standard of low-end high-purity quartz, and it may have the potential to produce middle-to-high end high-purity quartz after traditional purification. [ABSTRACT FROM AUTHOR]

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Multipurpose Utilization of Mineral Resources / Kuangchan Zonghe Liyong is the property of Multipurpose Utilization of Mineral Resources Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Iron is one of the most stubborn impurities in quartz minerals, and the iron content partly determines the various applications of quartz. Iron can exist in quartz in the forms of iron minerals, fluid inclusions, and lattice impurities. The removal of iron and the consequent purification of quartz minerals are the key processes to obtaining high-quality quartz. Iron removal methods including conventional pre-treatment, magnetic separation, acid leaching, microbiological, roasting, and flotation, as well as combined iron removal methods in quartz ore, are herein summarized. The separation mechanism of quartz and iron impurities and the latest research progress were explained and summarized, and the development prospects of quartz purification in the future were proposed based on the current progress and limitations of quartz iron removal.

The structure of high-purity natural quartz (superquartzite) is investigated by the methods of X-ray diffraction and electron backscatter diffraction. The change in the crystallinity index obtained by the method of Murata and Norman and the impurity chemical composition of superquartzite at various technological stages of separation (thermal crushing, sieving, chemical etching, high-temperature calcination) is established. Quartz purification by etching with a mixture of hydrochloric and hydrofluoric acids is found to increase the crystallinity index at all stages, except for preliminary thermal crushing and high-temperature calcination (at 1300 or 1400°C). The maximum value of the quartz crystallinity index is reached at the first stage of chemical etching. The greatest purification from impurities also occurred at the first stage of chemical etching. Electron backscatter diffraction reveals areas of increased local misorientation of crystallites, which are concentrated at the grain boundaries, "low-angle" boundaries (with a misorientation angle of less than 7°) and areas with an increased content of fluid inclusions, which can be observed in an optical microscope. An "orientation map" and map of local crystallite misorientation regions are constructed and analyzed using the MTEX software toolkit for MATLAB. It is determined that macrodefects of a dislocation nature cause a change in the crystallinity index. [ABSTRACT FROM AUTHOR]

Relevance. Due to the depletion of reserves of quartz deposits of transparent and semi-transparent granular quartz, which are the traditional sources for obtaining high-purity quartz for the needs of high-tech industries, it is urgent to assess the possibility of using previously unclaimed milky-white quartz deposits for these purposes. The aim of the research is to assess the possibility of using trace element composition of the initial and deep-enriched samples of milk-white quartz of different genetic types of the Novotroitskoe deposit for production of high-purity quartz based on their study. Methods. The prospects are assessed on the basis of a detailed study of the petrographic features and trace element composition of milk-white quartz by ICP-OES spectroscopy. Results. The milky-white quartz of the deposit is coarse-grained, intensely deformed, broken by a system of cracks, with sharp contacts with the host alternating mica shales and quartzites. In the central part, large-giant-grained quartz is blocky and sheet. In the near-contact part, quartz is more mineralized, recrystallized, with the content of newly formed grains in different genetic types from 3 to 50 %. The newly formed grains are formed along the deformation bands, do not contain mineral and fluid inclusions and are characterized by a high degree of purity. In all genetic types, with the exception of recrystallized quartz with a content of newly formed grains of ~50 %, high concentrations of impurity elements were found, in total exceeding the maximum permissible for high-purity quartz. This is due to the presence of a large number of fluid inclusions, and the difficulty of separating them from quartz grains, as well as the difficulty of removing mineral aggregates with quartz. Intensively recrystallized quartz with a total content of newly formed grains >50 % and impurity elements less than 50 ppm is suitable for producing high-purity quartz.

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Eastern Qinling, China is one of the important rare metal metallogenic provinces with extensively distributed granite pegmatite dikes. The No. 5 granite pegmatite intruded into the granitic gneiss of the Qinling Group, and the major minerals are quartz (39.8%), K-feldspar (18.8%), albite (36.3%), muscovite (3.4%), and garnet (1.1%). Monazite U–Pb isotopic dating indicates that the No. 5 pegmatite from the Eastern Qinling was emplaced at ca. 420.2 ± 2.2 Ma, which confirms that high-purity quartz mineralization probably formed during the Early Devonian. In-situ laser ablation inductively coupled plasma mass spectrometry analysis of quartz show that quartz samples from Eastern Qinling have total trace element concentrations (Al, Ti, Sc, Li, B, Cr, Mn, and Fe) ranging from 23.2 to 52.8 ppm, slightly higher than the quartz (impurity element content from 13.4 to 25.9 ppm) of the Spruce Pine high-purity quartz deposit in western North Carolina. The No. 5 pegmatite of Eastern Qinling could be defined as one high-purity quartz deposit of China. [ABSTRACT FROM AUTHOR]

High-purity quartz (HPQ) is an important material widely used in many high-tech industries. It is a product processed from pure natural quartz raw materials, so selecting suitable quartz raw material is the key to successfully processing HPQ. Hydrothermal quartz vein is one of the most likely raw materials to be purified into HPQ because of its high SiO2 content. This study focuses on the evaluation of HPQ raw material potential of the two gold-bearing quartz vein tailing resources in Chibougamau (CBG) and Tianjingshan (TJS). Petrography and the contents of impurity elements in the two vein quartz samples before and after processing were studied by optical microscope, SEM, Raman spectrometry, XRD, LA-ICP-MS, and bulk solution ICP-OES. Petrographic results reveal that major impurities in quartz are feldspar, mica, iron compounds, ankerite, rutile, silicate melt, and fluid inclusions. LA-ICP-MS analysis result shows that the SiO2 contents are between 99.953–99.971 wt.% in CBG raw quartz and 99.969–99.976 wt.% in TJS raw quartz, respectively, with very low contents of impurity elements, except for Ca. Bulk solution ICP-OES analysis demonstrates that the CBG processed quartz sand has total impurity contents of 56.8 µg·g−1, with 13.1 µg·g−1 Al and 6.6 µg·g−1 Ti, and the TJS processed quartz sand has the total impurity contents of 85.2 µg·g−1 with 29.4 µg·g−1 Al and 6.1 µg·g−1 Ti. Both the contents of Al and Ti fit with the lattice-bound criteria for HPQ. These results, for most of the impurities, are likely hosted by silicate melt, fluid, and mineral inclusions, indicating that these two hydrothermal raw vein quartz samples can be upgraded to HPQ after processing by more advanced methods. Therefore, the CBG and TJS quartz vein deposits would be considered as potential future resources for HPQ to realize efficient recovery and utilization of tailings resources and to improve mine economic benefits.

Abstract: Quartzites are widespread within Earth's lithosphere, but their highly pure varieties occur quite infrequently. With the development of alternative energy sources, including solar, and with increasing demand for high-purity quartz for optics, interest has risen in high-purity silicon-bearing materials. The quartzites discovered in the southeast part of the Eastern Sayan Mountains are particularly attractive for exploration in terms of their raw material quality and feasibility to be enriched. For this reason, their genesis also merits study. Available geochemical data show that chemogenic (d18O > 29.2‰) siliceous-carbonate sediments of the Irkut Formation are fairly pure (impurity elements < 800 ppm), and that half the impurities are easily removed carbonate components of the rock. Bedded quartzites remote from the intrusive granitoids and near-contact quartzites were recognized based on geochemical and petrographic data. Influenced by the Sumsunur granitoids, the near-contact quartzites originally contained > 0.9% impurities, but later, under the action of sliding slabs of ophiolite dynamothermal treatment reduced impurities to < 100 ppm, resulting in "superquartzites" (highly pure quartzites). The presence of only minor structural impurities is due to the enrichment capacity of superquartzites to 10.1 ppm (7.2 ppm under special conditions) of 10 elements: Fe, Al, Ti, Ca, Mg, Cu, Mn, Na, K, and Li.Graphical Abstract: [ABSTRACT FROM AUTHOR]

This study focuses on the retrograde rheological and chemical evolution of quartz and the behaviour of quartzites during retrograde metamorphism following dry high grade metamorphism at 750°C, 7 kbar. SEM-CL and LA-HR-ICP-MS are applied to document quartz texture and chemistry, respectively. Four generations of quartz were distinguished by SEM-CL; Qz1, Qz2, Qz3 and Qz4. Qz1, brecciated and partly dissolved old grains, is enriched in B, Al and Ti when compared with the other types. Qz2, formed during brecciation and partial dissolution of Qz1, has low Al contents (<50 ppm) but, due to rutile inclusions, variable Ti contents when occurring in amphibolite (210–10 ppm) but more consistent values when occurring in quartzites (peak value 32 ppm). Qz3, dark grey luminescent quartz forming fluid migration channels (fluid pathways), has Ti < 5 ppm and Al contents below 10 ppm and B < 1 ppm. Qz4, comprises are group of quartz later than Qz3 filling micron thick cracks and pods with very low luminescent quartz, i.e. darker than Qz3. The textural and chemical evolution of quartz in our study is explained by two major influxes of aqueous fluids during regional uplift and retrogression. They facilitated rehydration and recrystallisation in the otherwise dry high grade quartzites. The first introduction of aqueous fluids was associated with brecciation of the high grade quartz (Qz1) and dissolution/precipitation of quartz (Qz2). Ti in quartz geothermometry (Wark and Watson, Contrib Mineral Petrol 152(6):637–652) gives 626°C in agreement with the retrograde PT-path deduced from phase diagrams. Later fluid influx associated with scapolitisation of amphibolite caused localised recrystallisation (Qz3) and alteration of biotite to muscovite along mm-wide fluid migration channels. During subsequent deformation, Qz3 deformed plastically and recovered by subgrain rotation recrystallisation (SGR), resulting in a reduction of grain size, whereas Qz1 quartz formed micro faults. Qz2 was plastic but did not experience SGR to the same degree as Qz3 quartz. Increased plasticity and recovery rates most likely relate to an increased H2O fugacity and the depletion in trace elements of the quartz lattice by promoting strain softening processes dislocation climb and recovery. [ABSTRACT FROM AUTHOR]