The production of high-purity quartz sand involves selecting and finely processing materials. They are natural quartz crystal, silicon stone, or quartzite. This material finds uses in glass manufacturing, water treatment, ceramics, and refractory materials. The production process generally includes these steps: selecting ores, crushing them, screening, washing, grinding, removing impurities, drying, and packaging. Now, let’s dive deeper into these steps.
I. High-Purity Quartz Sand Production Process
1. Ore Selection
High-purity quartz sand is typically made from materials such as silicon stone, quartzite, or natural quartz crystal. The raw materials are manually crushed, sorted, and prepared before being placed into storage bins.
2. Crushing
The crushing process involves the use of jaw crushers, impact crushers, and sand-making machines. Quartzite is uniformly fed into a jaw crusher by a vibrating feeder for coarse crushing. The crushed quartzite is then transported to a sand-making machine for fine crushing.
3. Screening
A circular vibrating screen is used to separate qualified sand and stones. Quartz sand particles with a size of less than 1mm are sent to a sand washer to remove stone powder and dust. While particles larger than 6mm are returned to the crushing system for re-crushing. This integrated screening and washing system forms a closed-loop process in conjunction with the crushing system.
4. Washing
Qualified sand and stones are placed in a washing pool according to the process standards. It is rinsed with clean water to remove impurities adhering to the surface of the ore. Operators involved in the washing process must wear clean protective boots.
5. Grinding
The quartz sand is ground into a fine powder to prepare it for impurity removal and produce high-purity quartz powder.
6. Impurity Removal
Impurity removal is achieved through several methods:
Gravity Separation: Shaking tables with appropriate water flow can effectively reduce mica content.
Magnetic Separation: Strong magnetic substances in quartz sand can be removed. Because various minerals have different magnetic properties.
Flotation: Mineral particles have different surface physical and chemical properties. Mica, feldspar, and iron-bearing minerals can be separated from quartz sand.
Acid leaching: Soak the quartz sand with a mixed acid solution of HCl and HF for six days. Mainly removes metal oxides and some silicate minerals. Acid leaching is an essential purification step in the production of high-purity quartz sand. This step is important, especially for quartz glass used in optical applications and photovoltaic semiconductors.
7. Washing
After acid leaching, the residual liquid containing dissolved impurities adheres to the quartz sand surface. This liquid is removed through a washing process. to disperse impurities and residual liquid into the liquid phase. Complete the washing process.
8. Drying and Inspection
The quartz sand is dehydrated and dried for inspection before packaging.
II. Challenges in High-Purity Quartz Sand Production
1. High-purity quartz sources are limited
High-purity quartz sand is mainly derived from granite quartz and vein quartz. Although natural quartz crystal has high purity and few inclusions. But they are mainly used in crystal manufacturing. But, high-grade natural quartz crystals are scarce and unevenly distributed. and lower quartz content in vein quartz. Procuring enough raw materials for high-purity quartz sand production poses a challenge.
2. Purity Testing and Quality ControlPurity Testing and Quality Control:
Leading international companies benefit from comprehensive research and testing systems. It gives them a competitive edge in ensuring product quality and consistent batch supply. High-purity quartz sand quality depends on factors like impurity levels and production materials. Conducting online tests at each production stage is essential to maintain product quality. ICP-OES is an effective method for measuring trace chemical compositions in high-purity materials.
3. Treatment of Acid-Washing Waste
Acid washing is an essential purification step. But it generates a substantial volume of acidic, high-salinity, highly colored, and turbid wastewater. This wastewater, particularly fluoride-containing effluents, presents a significant environmental challenge. So it is critical to manage waste to meet local environmental regulations effectively. At the same time, cost control is still the main concern of quartz processing companies.
III Global High-Purity Quartz Sand Leading Producers
The global production capacity for high-purity quartz sand is concentrated in a few key companies, including Unimin in the United States, TQC in Norway, Pacific Quartz, and Russian Quartz LLC.
1. Unimin (Now Sibelco)
Company Overview
In the global quartz industry, US-based Sibelco has established itself as a dominant player. Sibelco has an absolute monopoly on international high-purity quartz sand products of 4N8 and above. The market share exceeds 90%. They have an absolute pricing advantage in the quartz sand industry.
Sibelco’s main products include quartz, feldspar, nepheline syenite, olivine, calcium carbonate, clay, kaolin, lime, and limestone products. Their silica (quartz) is a high melting point, hard, chemically inert mineral. They are widely used in glass, ceramics, construction, metallurgy, and other fields. The company’s silica products include dry sand, green sand, low iron sand, and calcined sand.
Sibelco’s fused quartz is a high-temperature crystalline form of high-purity quartz. Produced by calcination at 1500°C and iron-free grinding. Sibelco fused quartz offers strong advantages in whiteness and durability. It is widely used in the fields of artificial stone, coatings, and polymers.
Source
Sibelco’s high-purity quartz sand is sourced from the White Mountains region of Spruce Pine, North Carolina. It is the only high-purity quartz deposit in the world affected by the Allegheny diagenetic movement. This deposit has the advantages of large ore body size, few quartz fluid impurities, and stable ore quality. Currently, the mining rights of the Spruce Pine mining area are held by TQC of Norway and Sibelco North America (formerly Unimin). Unimin (Sibelco) has mined in the area since 1970. Owning the mining rights to the Spruce Pine deposit is a key factor in Unimin (Sibelco) becoming a global industry giant.
2. TQC
Company Overview
Norwegian TQC has been at the forefront of high-purity quartz production in western Norway since 1996. It operates multiple underground and surface mines. TQC consolidates the efforts of its US subsidiary Engeseth Ceramics as well as KT Feldspar and Feldspar AS. It created a new company focused on the production of quartz, feldspar, and mica products. TQC’s high-purity quartz products are used in a variety of industries, including semiconductor, solar, optical, lighting, and bioactive glass.
Sources and Capacity
The high-purity quartz extracted and processed by the company ranks among the best in the world. This virgin quartz comes primarily from the Spruce Pine Mine in North Carolina. The pegmatite formations there contain almost no impurities. TQC is licensed in Norway to produce 30,000 tons of high-purity quartz per year.
3. Pacific Quartz
Company Overview
Jiangsu Pacific Quartz Co., Ltd. is a vertically integrated enterprise specializing in high-quality quartz material processing. Founded in 1992, the company went public on the Shanghai Stock Exchange A-share main board in 2014 (Stock Name: Quartz Co., Stock Code: 603688). The company has developed over thirty years. It has become a benchmark enterprise in China’s quartz material industry.
Main Products
The company excels in various industries, including lighting, photovoltaics, fiber optics, optics, semiconductors, and more. They offer a wide range of quartz products, such as high-purity quartz sand, quartz tubes (rods), large quartz diffusion tubes, cylinders, ingots, plates, and various components. In the lighting sector, they specialize in quartz tubes and rods for various lighting applications. For fiber optics, they provide fiber-grade jackets, core tubes, tubes, and rods. In semiconductors, they focus on semiconductor-grade quartz tubes, rods, cylinders, ingots, plates, and quartz ceramic crucibles. They also supply synthetic quartz materials for UV optics, standard quartz materials for optics, and infrared optical-grade quartz materials. In the photovoltaic industry, they manufacture solar-grade quartz tubes, rods, milky quartz ingots, and quartz sand.
Source
The company’s quartz is mainly purchased from external sources. In 2021, overseas quartz procurement accounted for 93.32%. Imports mainly come from Brazil, Africa, India, the United States, and other countries and regions. Their primary suppliers provide stability. They have signed long-term framework agreements with suppliers.
HanLink can provide different specification silica powder. They are used in the film industry and the plastic industry. They are also used as an anti-scratch, wear-resistant filler, matting agent, and additive for powder coatings in paint formulations
