Precision-engineered high-purity silica products fabricated to drawing, serving semiconductor foundries, analytical spectroscopy, vacuum furnaces, and chemical processing facilities worldwide.
Precision spectrophotometer cells featuring molecular thermal fusion bonding with zero adhesive contamination, guaranteed matching transmission tolerance across UV-Vis spectroscopy channels.
Flat-lapped and double-side polished vacuum viewport substrates with surface roughness Ra < 0.5 nm, providing extreme thermal shock endurance under high-vacuum chamber inspection.
Heavy-duty circular quartz substrates designed for extreme heating environments, thermal plate shielding, and industrial culinary or pyrometallurgical heating platters with non-toxic purity.
Molded and hand-welded transparent silica combustion boats designed for tube furnace sample calcination, semiconductor diffusion carriers, and trace metal elemental analysis.
Micro-aperture capillary draw tubes engineered for gas chromatography, electrophoresis, optical fiber alignment sleeves, and precise medical flow dispensing systems.
Calibrated rough-ground quartz blanks featuring strict thickness tolerance and square-cut edges, serving as heavy-duty carrier substrates during silicon wafer grinding and CMP lapping.
Heavy-wall fused silica tubing with thick concentric cross-sections, providing outstanding mechanical pressure resistance for high-pressure sight gauges and chemical feed lines.
Heavy-bottom molded quartz beakers engineered to endure rapid thermal cycles up to 1200°C without devitrification, completely resistant to hot concentrated acids (excluding HF).
In the lexicon of industrial materials, Milky Quartz Tubes (commonly designated as opaque fused silica or porous-matrix quartz glass) represent a distinctive branch of high-purity amorphous silicon dioxide (SiO₂ ≥ 99.9%). While transparent quartz tubes are melted and continuously refined to evacuate virtually all gaseous inclusions, milky quartz is intentionally engineered with a homogeneous distribution of microscopic gas micro-bubbles (typically ranging from 5 to 30 microns in diameter) trapped within the fused silica matrix.
This micro-structural morphology acts as an intense scattering mechanism across the infrared (IR) and visible spectrum. Instead of allowing thermal radiation to transmit directly into adjacent components—as occurs with clear quartz—milky quartz diffuse-reflects and scatters infrared waves, functioning as an exceptional thermal barrier and radiation shield. When utilized in heating jackets, furnace muffles, and semiconductor diffusion chambers, milky quartz delivers radial thermal uniformity while preventing hot-spot degradation.
Furthermore, opaque fused silica maintains identical chemical inertness and extreme thermal shock tolerance compared to optical clear quartz: its coefficient of thermal expansion remains an extraordinary 5.5 × 10⁻⁷ /°C, permitting instant transitions from 1100°C to cold water quenching without fracture.
Precise physical, thermodynamic, and mechanical constants for furnace engineering and design validation.
| Property Parameter | Milky / Opaque Fused Quartz | Clear Transparent Fused Quartz | Engineering Impact in Procurement |
|---|---|---|---|
| Chemical Purity (SiO₂) | ≥ 99.90% | ≥ 99.99% | Ultra-low heavy metal contamination; prevents batch poisoning. |
| Bulk Density | 2.05 – 2.15 g/cm³ | 2.20 g/cm³ | Lower density due to closed micro-bubble cellular structure. |
| Thermal Expansion Coeff. (20–300°C) | 5.4 × 10⁻⁷ /°C | 5.5 × 10⁻⁷ /°C | Immune to extreme thermal gradient shock; superior to ceramics. |
| Maximum Continuous Working Temp | 1050°C – 1100°C | 1100°C – 1150°C | Maintains structural stability under continuous process cycles. |
| Short-Term Softening Point | 1660°C – 1680°C | 1683°C | Survives transient thermal spikes during annealing and CVD runs. |
| Infrared Radiation Behavior | Scattering / High Emissivity (0.85–0.90) | Direct Transmission (≥ 90%) | Milky quartz converts direct radiative hotspots into diffuse heat. |
| Dielectric Strength (20°C, 1MHz) | 2.5 × 10⁷ V/m | 3.0 × 10⁷ V/m | Exceptional electrical insulation inside high-voltage plasma setups. |
| Hydroxyl ([OH⁻]) Concentration | < 30 ppm to 150 ppm (Grade dependent) | < 5 ppm to 20 ppm (Electrically fused) | Governs high-temperature viscosity and devitrification rates. |
Donghai Kemzo Quartz Products Co., Ltd. capitalizes on the world's richest natural quartz reserve belt, vertical integration, and continuous technical evolution since 2011.
Situated directly in Donghai County (China’s Crystal Capital), we hold direct access to superior silica feedstock. Raw quartz crystals undergo ultrasonic scrubbing, flotation, and acid-leaching to eliminate iron, titanium, and alkali ions before the furnace charge.
Our proprietary electric arc and continuous gas-fired melting lines enable precise bubble density control for milky quartz tubes. Outer diameters from 1.5 mm up to 450 mm can be pulled with wall thickness tolerances controlled within ±0.15 mm.
Certified under ISO 9001 and Jiangsu High Technology Enterprise status, every export lot undergoes laser micrometer concentricity verification, spectrophotometric scatter testing, and polarizing stress inspection to eliminate residual thermal stress.
Serving clients across North America, Europe, East Asia, and South America under FOB, CIF, DDU, and DDP terms. Products feature individually partitioned foam isolation, vacuum bubble wrapping, and heavy plywood export crates with shock sensors.
Standard tube drawing is only the beginning. Kemzo Quartz integrates extensive secondary fabrication workshops equipped with precision CNC glass lathes, automatic diamond cut-off saws, ultrasonic drilling heads, and hydrogen-oxygen glassblowing benches.
We regularly machine, shape, and weld milky quartz tubes with custom quartz flanges, ground standard-taper joints (ST 24/40, 29/42, etc.), closed hemispherical ends, spiral cooling channels, and threaded ports for thermocouple insertions. Every part is post-annealed in electric ovens up to 1215°C to release mechanical stresses prior to crating.
Key market transitions shaping procurement specifications for advanced semiconductor nodes, solar photovoltaics, and sustainable thermal processing.
Next-gen semiconductor furnace designs (3nm/2nm process equipment) require extreme micro-pore diameter consistency. Traditional opaque quartz had random void sizes; upcoming standards demand controlled bubble distributions (< 15 μm) to eliminate local mechanical stress concentrators and ensure uniform infrared reflectance.
With the rapid expansion of n-type TOPCon, HJT, and Perovskite-Silicon tandem solar wafer lines, demand for heavy-diameter milky quartz heating muffles has surged. Leading Chinese exporters are scaling continuous rotary fusion technology to supply outer diameters exceeding 450–600 mm with structural wall integrity.
Device sensitivity to trace ionic contamination (Li, Na, K) has tightened drastically. Sourcing protocols are moving toward strict < 0.5 ppm threshold limits for mobile alkali ions to avoid premature devitrification (cristobalite crystal growth) at continuous 1100°C furnace runs, extending quartz tube service lifespans by over 40%.
Global ESG compliance is accelerating the transition from fossil fuel oxy-hydrogen burners to renewable electric furnace fusion. This clean melting architecture drastically lowers embedded carbon metrics while practically eliminating hydroxyl ([OH⁻]) pickup from combustion vapor.
Direct engineering answers to technical queries, dimensional tolerances, material certifications, and export logistics.
Milky quartz contains a controlled matrix of microscopic encapsulated air micro-bubbles that diffuse and scatter infrared and visible wavelengths, acting as a thermal shield with high emissivity. Clear quartz is melted to evacuate bubbles, providing optical transparency (>90% transmission). Both share identical chemical resistance and an ultra-low expansion coefficient of 5.5 × 10⁻⁷ /°C.
For standard outer diameters (OD 10 mm – 150 mm), our outer diameter tolerance is maintained within ±0.2 mm to ±0.5 mm, and wall thickness tolerance within ±0.15 mm to ±0.25 mm. For custom CNC-ground or precision-machined sections, we routinely hit ±0.05 mm, fully compliant with DIN ISO 2768-m standards.
Yes. With over 11 years of dedicated OEM/ODM experience, our engineering department reviews STEP, DWG, DXF, or PDF engineering prints. We confirm structural feasibility, draft thermal expansion budgets, and output precision prototypes typically within 5–7 business days.
Each tube is individually capped, wrapped in multi-layer polyethylene shock film, and isolated inside slotted high-density EPE foam compartments so glass surfaces cannot contact one another. These inner boxes are secured inside heavy-duty, fumigation-free wooden export crates rated for ocean pallet loads and air freight handling.
Devitrification (re-crystallization into high-temperature cristobalite) occurs above 1150°C if the quartz surface is contaminated by finger grease, dust, or alkali salts (Na, K, Ca). When kept clean and operated in neutral/acidic atmospheres, our tubes run continuously at 1100°C for thousands of hours without surface haze or structural sagging.
We support multiple payment methods including T/T, L/C at sight, and PayPal across major currencies (USD, EUR, AUD, GBP, CNY). Available delivery terms span EXW, FOB Lianyungang/Qingdao/Shanghai, CFR, CIF, and door-to-door DDU/DDP services worldwide.
Contact our senior technical sales team with your exact dimensions, wall thicknesses, operating temperatures, or drawings. Receive verified quotation, DFM feedback, and official material data sheets within 1 hour.