Ceramic Valve Solutions for Silicon Industry Waste Treatment
Reliable flow control for corrosive chlorosilane waste, abrasive silicon solids and crystallizing residues in waste gas, wastewater and solid waste treatment systems
Wear-resistant, corrosion-resistant and anti-clogging ceramic valve solutions for waste gas, wastewater, high-boiling residues and solid waste in polysilicon and silicone plants
Silicon Industry Waste Gas, Wastewater & Solid Waste Treatment
Recovery and environmentally safe treatment of:
- Waste gas: tail-gas recovery
- Waste liquid: distillation residues and high-boiling compounds
- Solid waste: cold-hydrogenation slurry, filter cake, and hydrolysis residues
Key Industries
- Organic Silicon
- Polysilicon
Operating Conditions
Operating temperature below 200°C. Media include silicon powder, hydrochloric acid, calcium chloride, precious-metal catalyst particles, higher chlorosilanes such as Si₂Cl₆ and Si₃Cl₈, residual SiHCl₃, SiCl₄ and SiH₂Cl₂, dissolved metal chlorides such as AlCl₃, FeCl₃ and TiCl₄, entrained trace silicon powder, and fine SiO₂ particles
| Parameter | Value | Parameter | Value |
|---|---|---|---|
| Medium | Hydrochloric acid, calcium chloride, silicon dioxide, precious-metal catalysts, etc. | Phase | Gas-solid and solid-liquid two-phase |
| Operating pressure | 6-30 bar | Pressure class | Class 150 |
| Differential pressure (ΔP) | ≤1 MPa | Nominal size | DN40-DN200 |
| Operating temperature | <250°C | Thermal shock | None |
| Characteristics | Abrasion and corrosion |
Medium details: Silicon powder
| Property | Specification |
|---|---|
| Chemical composition | Hydrochloric acid, calcium chloride, silicon dioxide and precious-metal catalysts |
| Corrosive components | Hydrochloric acid and calcium chloride |
| Corrosiveness (pH) | Not specified |
| Solids content | Relatively high |
| Particle size | 150-600 μm |
| Particle hardness | Mohs 6-7 (Highly Abrasive) |
Special Operating Conditions
Abrasion and Corrosion
- Hydrolysis of chlorosilanes produces HCl, which weakens metal surfaces. Continuous erosion by silicon powder, SiO₂, and metal-salt particles strips away the corroded layer, accelerating the damage
- Metal chlorides precipitate and crystallize, while high-boiling polymers adhere to the valve wall and solid deposits settle in the valve cavity. Conventional ball valves are prone to material accumulation, seizure, and failure to operate
- Intermittent operation of residue-discharge and drain valves creates repeated thermal cycling. Thermal expansion and contraction of crystalline deposits further damage the sealing surfaces
- The media are toxic and flammable. External leakage can generate HCl acid mist, while internal leakage may cause process cross-contamination and serious safety incidents. Low-emission sealing is therefore essential
Keywords: High Hardness · Powder Media · Crystallization and Scaling · Valve Seizure
Process Pain Points and Key Opportunities
Original Valve Materials and Types
Most existing valves use metal hard-seated or fluorine-lined designs, including globe valves, butterfly valves, and ball valves
Problems with Existing Valves
Hard particles cause severe abrasive wear. Valve seizure can score the sealing surfaces, while wear of the secondary seal leads to internal leakage
Corrosive media attack metal hard-seated valves
Crystallization and deposits cause valve components to seize or react with the process medium, resulting in blockage
Replacement Interval and Service Life
Service life varies from one to six months
Losses Caused by Shutdowns and Maintenance
- Interrupted production reduces operating efficiency
- Leakage of flammable or explosive gases may cause production accidents
- External leakage of process media causes environmental contamination
Additional Information
The silicon chemical industry is subject to strict environmental supervision. Process leaks can cause pollution and may result in production suspension or mandatory rectification
Keywords: High Cost · Short Service Life · Frequent Maintenance · Environmental Compliance · Crystallization and Scaling
Why Choose Ceramic Valves?
Superior Wear Resistance
- Structural ceramics reach HRA 90, substantially harder than the silicon powder handled in the process (approximately HRA 70), providing excellent resistance to abrasive wear
- Their inorganic, non-metallic composition and interlocking crystalline structure prevent metal adhesion and micro-welding, reducing damage caused by crystalline deposits and surface fatigue
Superior Corrosion Resistance
- Structural ceramics are naturally corrosion-resistant and can withstand complex corrosive media containing chlorosilanes and chlorides
- Metallic materials may suffer pitting, hydrogen embrittlement and other forms of chemical corrosion. Ceramics do not undergo electrochemical corrosion, providing long-term resistance without embrittlement
Fully Ceramic-Lined Ball Valve Design
- The fully ceramic-lined flow path completely isolates the process medium from the metal valve body, providing virtually zero metal contamination. Its self-cleaning action also helps prevent crystalline deposits and valve seizure
- The solid ceramic ball provides long-term impact resistance without significant performance degradation
Service-Life Guarantee
Minimum service life: Control valves ≥3 years; on/off valves ≥5 years
Lower replacement frequency means fewer plant shutdowns, reduced production losses, lower total operating costs and safer, more reliable operation
Conclusion: Specialized ceramic materials have successfully solved the severe wear and high-velocity particle erosion problems affecting conventional valves. These valves have been installed at critical waste-treatment points in organosilicon production systems operated by several of the world’s top ten organosilicon manufacturers
Case Study
End Users
- Xinjiang East Hope New Energy Co., Ltd., China, since 2016
- Xinjiang Daqo New Energy Co., Ltd., China, since 2016
- Sichuan Yongxiang Polysilicon Co., Ltd., China, since 2018
- Inner Mongolia Dongli Photovoltaic Electronics Co., Ltd., China, since 2018
Fluorine-lined valves were traditionally specified in imported process packages for waste treatment in polysilicon plants. However, these valves could not operate reliably because the waste streams contain hard particles such as silicon powder and chlorosilanes carried over from upstream processes
Polysilicon manufacturers subsequently commissioned major Chinese engineering institutes to optimize and upgrade the process, including further improvements to valve materials and specifications. Because waste-treatment flow rates fluctuate with changes in production load, the process requires high-performance control valves capable of stable, long-term operation. Ceramic valves have successfully addressed this challenge
As waste-treatment processes continue to improve, high-boiling residues are now cracked and recovered for reuse. These systems contain precious-metal catalysts and aluminum compounds. Ceramic valves have received strong recognition from plant operators and engineering institutes for their excellent corrosion resistance
Conclusion
Actual service life: Control valves ≥3 years; on/off valves ≥5 years
Silicon Waste Treatment: site photographs
Commonly Used Products
FCCV1
Standard Ceramic Ball Valve
The FCCV1 series is the standard model in the ceramic ball-valve range. It is designed for highly corrosive and severely abrasive service at temperatures up to 180°C and differential pressures up to 2.0 MPa
- Wide sealing surfaces and scraper-type valve seats provide reliable shutoff and extended service life
- The ball and valve-seat sealing surfaces are match-lapped to ensure tight sealing
- The stuffing box incorporates live loading that maintains a constant packing load even after substantial wear, extending packing service life
- The symmetrical valve design provides bidirectional sealing with no flow-direction restrictions
- Wide ceramic flange-sealing surfaces protect the metal flanges from erosion and corrosion by the process medium
ELCV
Economical Ceramic Ball Valve
The ELCV uses essentially the same basic structural design as the FCCV1 but does not include a top mounting platform. Materials can be selected flexibly according to the operating conditions, providing a more economical ceramic-valve solution, although overall reliability is slightly lower than that of the FCCV1
| Parameter | Specification |
|---|---|
| Valve design | Floating-ball construction |
| Flange standards | ASME B16.5 / HG / DIN / JIS |
| Pressure rating | PN10-PN50 / ASME Class 150-300 |
| Operating temperature | −40°C to 180°C |
FCRV
Ceramic C-Ball Valve
The valve features a special C-shaped design. Its ball consists of a C-shaped metal support and a one-piece ceramic ball segment mechanically connected and securely embedded together. The ceramic segment protects the metal support from direct erosion by the process medium
The concentric design keeps the ceramic ball segment in continuous contact with the seat during operation, allowing it to scrape away deposits adhering to the sealing surfaces and maintain reliable shut-off performance. It is particularly suitable for media prone to crystallization, scaling, agglomeration, high solids loading and valve jamming. Its cavity-free design minimizes material accumulation inside the valve
Size range: DN50-400
View FCRVContact Us
Talk to our team about your silicon waste treatment application
Discuss your application
