How to Produce 99.995% SiO₂ Quartz for Semiconductor/ Solar Industries?

2026-01-25

Producing 99.995% pure silicon dioxide (SiO₂) quartz for semiconductor and solar industries demands highly controlled processes to achieve the stringent purity requirements for electronic-grade materials. Below are the key steps involved in obtaining ultra-pure quartz:

1. Raw Material Selection

• Begin with natural quartz that has high purity. Opt for quartz deposits with minimal contamination of heavy metals, alkalis, and other impurities.
• Source quartz from areas known for their high-grade geological formations (such as Spruce Pine in the U.S., famous for its high-grade quartz).

2. Crushing and Grinding

• Crush and grind the quartz to the desired particle size using equipment made of highly inert material to prevent contamination. Avoid tools containing metals that could leach into the material.

3. Chemical Pre-Treatment

• Acid Leaching: Immerse the crushed quartz in strong acids (such as hydrofluoric acid, sulfuric acid, or hydrochloric acid) to remove surface contamination and impurities like iron and aluminum.
• Washing: After leaching, thoroughly wash the quartz in ultra-pure water to remove residual acids.

4. Thermal Treatment

• Heat the quartz in high-temperature furnaces (above 1000°C) to oxidize and volatilize impurities. Care needs to be taken to control the atmosphere (e.g., high-purity oxygen) during heating.

5. Purification via Fusion

• For ultra-high-purity quartz, fuse the material in electric arc furnaces made of high-purity materials like graphite or platinum.
• During melting, impurities are segregated, and ultra-pure quartz glass is produced.

6. Physical Separation Techniques

• Use advanced physical separation methods such as flotation or magnetic separation to remove remaining metallic impurities (e.g., iron or titanium).
• Employ size and density separation to isolate ultra-pure quartz grains.

7. Refinement Using Plasma or Chemical Vapor Purification

• Plasma Treatment: Subject the quartz particles to plasma purification to remove traces of volatile impurities.
• Chemical Vapor Deposition (CVD): Alternative methods involve CVD processes to deposit high-purity SiO₂ layers.

8. Carbon Removal

• Ensure removal of organic and carbon-based contaminants by treating quartz with oxidizing agents at high temperatures.

9. Quality Control and Testing

• Measure the purity using high-precision analytical methods such as:
  • ICP-MS (Inductively Coupled Plasma Mass Spectrometry)
  • XRF (X-ray Fluorescence)
  • Spectroscopic techniques.
• Ensure the presence of trace impurities (e.g., iron, titanium, alkali metals) is reduced to below 10 ppm or even in ppb ranges.

10. Final Packaging

• Package the quartz in ultra-clean containers in a controlled cleanroom environment (ISO Class 5 or better) to prevent post-purification contamination.

Considerations for Semiconductor/Solar Industries:

• Silicon Wafer Production: Beyond pure SiO₂ production, the quartz might be converted into high-purity silicon (Si) through reduction processes like carbothermal reduction in arc furnaces.
• Solar industry: Ultra-pure quartz is used to produce polysilicon for photovoltaic cells, necessitating further processes like Siemens processing or fluidized bed reactors.

Challenges:

• Maintaining ultra-high purity levels requires stringent control at every step to avoid contamination.
• Accessible deposits of high-purity quartz are limited globally.
• Capital expenditure for advanced equipment (e.g., plasma purification, CVD systems) is high.

By implementing advanced purification techniques and adhering to strict quality control, it is possible to produce 99.995% SiO₂ quartz that meets the demands of semiconductor and solar industries.

Prominer (Shanghai) Mining Technology Co., Ltd. specializes in providing complete mineral processing and advanced materials solutions globally. Our core focus includes: gold processing, lithium ore beneficiation, industrial minerals. Specializing in anode material production and graphite processing.

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