Кварц is one of the most abundant and versatile minerals on Earth, playing a critical role in numerous industries from construction to high-tech electronics. For a process from raw minerals to finely processed powder, advanced equipment like a quartz grinding mill becomes essential. Understanding quartz’s properties and processing needs is key to unlock its full potential.
1 Mineralogical Characteristics & Key Properties
Quartz (SiO₂) is an oxide of silicon with a framework structure. It generally refers to α-quartz (low-temperature quartz, trigonal system) and β-quartz (high-temperature quartz, hexagonal system), with a transformation temperature of 573°C. Unspecified quartz typically means α-quartz.
In mineralogical classification, quartz belongs to the oxide class and quartz group. Sometimes, due to its position at the end-member of silicates, it is also classified as a silicate. The quartz group includes various polymorphs of SiO₂ like quartz, cristobalite, tridymite, coesite, and stishovite, with the latter two being high-pressure phases.
The theoretical chemical composition of quartz is 100% SiO₂, or Si 46.74% and O 53.26%. Natural quartz is relatively pure but can contain trace impurity elements like Al, K, Na, Li, Ca, Fe, Mg, Mn, Ti, Cu, Zn, Cr, Ni, B, P due to isomorphous substitution.
The open framework crystal structure of quartz SiO₂ results in a relatively low density of 2.65. However, the Si-O bonds in the [SiO₄] tetrahedra are strong, giving quartz a hardness of 7 on the Mohs scale. It is resistant to acids (except HF), slightly soluble in KOH solution, and has a high melting point (1710–1756°C), cooling into fused silica (quartz glass) upon solidification.
Quartz is a hard, wear-resistant silicate mineral with stable chemical properties. It is typically colorless or milky white but can show various colors due to impurities. It’s translucent, with a hardness of 7, brittle conchoidal fracture, vitreous luster, and specific gravity of 2.65. It exhibits optical activity, piezoelectricity, poor thermal conductivity, non-conductivity, and significant anisotropy in its electrical, thermal, and some mechanical properties.
2 The Past: Seven Major Mineral Resource Types of Quartz
Quartz is widely distributed in nature with diverse origins. Currently, there are seven main industrial deposit types for quartz mineral resources: Natural Crystal, Quartz Sandstone, Quartzite, Vein Quartz, Powdered Quartz, Natural Silica Sand, and Granitic Quartz.
Natural Crystal
A large, colorless, transparent quartz crystal mineral primarily composed of silica dioxide. It forms in cavities, rock fractures, joints, or faults under strict conditions requiring ample space, silica-rich hydrothermal fluids, specific temperature/pressure, and sufficient time.
Quartz Sandstone
A consolidated sandy sedimentary rock with quartz and siliceous clast content generally >95%. Accessory minerals are often feldspar, mica, and clay minerals, with few heavy minerals. The cement is typically siliceous.
Кварцит
A metamorphic rock formed from quartz sandstone or other siliceous rocks via regional or thermal contact metamorphism. Associated minerals can include feldspar, mica, clay minerals, and trace amounts of tourmaline, hematite, and zircon. Compared to quartz sandstone, it is denser, harder, and more compact.
Жильный кварц
Mainly formed by magmatic hydrothermal activity related to granite. It has a massive structure, simple mineral composition (almost entirely quartz), with SiO₂ content usually over 99%. Vein quartz deposits are typically small-scale, with steep occurrence, thickness from a few meters to tens of meters, and lengths from tens to hundreds of meters.
Powdered Quartz (Ammosite)
A natural powdered quartz ore with very fine particles and high SiO₂ content. It primarily forms from weathered siliceous parent rock, creating sedimentary weathering deposits. Specific geological conditions, warm-humid paleoclimate, and gentle paleotopography cause the siliceous rock to disintegrate, with water carrying away impurities to form the deposit.
Natural Silica Sand
A sandy quartz mineral resource formed by long-term natural weathering of parent rocks like granite, quartzite, quartz sandstone, and vein quartz. Associated minerals include feldspar, rock debris, mica, clay minerals, and heavy minerals like zircon, tourmaline, ilmenite, and amphibole. Mainly marine and lacustrine sedimentary sand deposits.
Granitic Quartz
The fundamental reason companies like Sibelco’s IOTA series achieved an international monopoly in high-purity quartz is their unique raw material – granitic quartz from Spruce Pine, North Carolina, USA. This specific quartz deposit has a legendary discovery story.
Initially mined for feldspar and muscovite, quartz was a waste by-product. In the 1970s, as crystal resources for quartz glass dwindled, finding alternatives became urgent. Through improved flotation technology, quartz from granitic pegmatites replaced crystal for producing high-purity quartz sand, a market the US still dominates today.
3 The Present: Typical Applications of Quartz
Quartz finds extensive applications. After various processing stages, it’s used in glass, foundry, ceramics, refractories, chemicals, petroleum extraction, water purification, construction, new energy PV, electronic semiconductors, optical fiber, optics, light sources, high-end fiber materials, industrial fillers, and more.
Largest Volume Application
The glass industry is the largest consumer of quartz, used widely in construction, automotive, new energy, and medical fields. Main products include flat, container, tempered, photovoltaic, electronic, and pharmaceutical glass.
In 2021, China’s glass output was 10.17 million weight boxes, consuming ~34.06 million tons of quartz sand. National data shows in 2023, China produced 9.69 million weight boxes of flat glass (consuming ~32.47 million tons quartz sand) and 24.78 million tons of PV rolled glass (consuming ~17.6 million tons of low-iron quartz sand at ~0.71t per ton of glass). Thus, flat and PV glass alone consumed over 50 million tons of quartz sand in 2023.
Downstream demand comes from real estate, automotive, appliances, PV, daily containers, and electronics. Historically, ~75% was real estate-related; future conventional glass demand grows slowly due to the property sector downturn. Driven by “Dual Carbon” goals, global PV installations will continue growing, sustaining PV glass demand increase.
To achieve the precise fineness required for various glass production stages, efficient size reduction is key. This is where a specialized quartz grinding millproves invaluable, ensuring consistent particle size distribution for optimal melting and product quality.
Highest-End Applications:
Semiconductors
The core of semiconductor IC manufacturing is chip production, involving single crystal growth, wafer manufacturing, IC chip production, and packaging. The most critical and demanding steps are silicon wafer manufacturing and wafer fabrication. Quartz is used mainly for semiconductor-grade quartz crucibles and auxiliary materials in wafer manufacturing.
Quartz products are used throughout silicon wafer and wafer processing in key steps like diffusion, oxidation, deposition, and etching. High-purity quartz sand of 5N2 purity can make semiconductor quartz crucibles, while 4N and 4N8 purity sands are for quartz materials used in wafer oxidation and diffusion.
Optical Fiber
Driven by large-scale information network construction, global fiber optic communication has developed rapidly. China is now the largest producer and consumer. Fiber preforms are the core of theindustrial chain. Quartz glass for fibers is a fundamental material. Quartz substrate and jacket tubes are high-end quartz pipes crucial in preform preparation.
Researchers from Jiuzhi Guangdianzicail Technology Co., Ltd. and the State Key Laboratory of Optical Fiber and Cable Manufacturing Technology used natural quartz powder and Plasma Solid Phase Outer Deposition (PSOD) to produce large-size quartz jacket tubes for single-mode fiber preforms. The products feature one-step forming, low hydroxyl content, few impurities, large specifications, and good vitrification, meeting single-mode preform needs. This offers new materials and processes for low-attenuation fibers with broad prospects in next-gen ultra-low loss communication fibers.
Hottest Applications
In recent years, “The New Three” – new energy vehicles, lithium batteries, and solar PV cells – have added luster to Chinese manufacturing, especially in exports, providing new momentum for high-quality economic development.
In the PV industrial chain, quartz products are pivotal. Besides PV glass made from ultra-clear, low-iron quartz sand, quartz crucibles produced from high-purity quartz sand are the most standout product in quartz downstream applications recently.
Quartz crucibles, a specialized quartz glass product, offer cleanliness, homogeneity, and high-temperature resistance. They are widely used in solar and semiconductor crystal silicon production and are consumables. Compared to regular quartz sand, high-purity quartz sand prepared via beneficiation offers better high-temperature resistance and thermal stability. As the core material, quartz sand purity is the key indicator ensuring superior crucible performance.
Epic Powder Quartz Grinding Mill
Processing quartz for demanding applications like high-purity quartz sand or fillers requires precise grinding and classification. Эпический порошок specializes in providing advanced quartz grinding mill. With grinding mill equipment ranging from Air classifiers and Ball mills to Jet mills, we can meet diverse production requirements for quartz and other minerals, ensuring optimal fineness, purity, and efficiency for your specific applications. Partnering with Epic Powder ensures you have the technology and expertise to handle various quartz materials and achieve your desired production outcomes. Contact us today to have your tailored-made quartz grinding mill.
