Overview of Application Scenarios
In the production processes of chlor-alkali, sodium chlorate, sodium hypochlorite, and other high-concentration oxidizing media, metal corrosion failure is a critical technical challenge. These media exhibit extremely strong corrosive properties towards conventional carbon steel, 304, and 316L stainless steels, requiring the use of corrosion-resistant materials such as nickel-based alloys or titanium/titanium alloys that can withstand chlorine gas, chloride ions, and oxidation.
Material Application Areas Breakdown
| Equipment | Recommended Material | Description |
| Electrolyzer Shells (Liner/Composite) | Titanium Gr2, Titanium Composite Steel Plate | Direct contact with electrolyte and chlorine gas |
| Anode Conductive Busbar | Nickel-based Alloys (Inconel 600/625) | High current, high-temperature, and high-chlorine environment, preventing stress corrosion |
| Anode Supports and Connectors | Incoloy 825, Monel 400 | Long-term contact with chlorine gas and hydrogen, resistant to pitting and stress corrosion |
| Filters, Heat Exchangers | Titanium Gr2/Gr7, Incoloy 825 | Chlor-alkali, sodium chlorate, high-temperature filtration and heat exchange |
| Evaporator/Condenser Systems | Hastelloy C-276/C-22 | High-concentration sodium hypochlorite, resistant to chlorine and oxidation |
| Valves, Pump Housings, Impellers | Titanium Alloys, Monel 400, Alloy 20 | Medium circulation and discharge |
Titanium/Titanium Alloys in Electrolytic Plants: Key Applications and Advantages
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Titanium Stability in Chlorine Environments
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Titanium forms a stable TiO₂ passive layer in wet chlorine and cold chlorine environments, making it virtually corrosion-resistant.
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In high-temperature chlorine and dry chlorine environments, titanium may undergo chlorination reactions, thus requiring cooling or humidification systems.
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Key Titanium Alloy Recommendations
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Gr2 (Commercial Pure Titanium): Most commonly used, cost-effective, and resistant to wet chlorine and alkaline corrosion.
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Gr7 (Palladium-Alloyed Titanium): Enhances resistance to pitting corrosion, suitable for harsh oxygen-reducing conditions.
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Ti-0.2Pd or Ti-3Al-2.5V: Increases strength and fatigue performance.
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Nickel-Based Alloys in the Chlor-Alkali Industry: Challenges and Value
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Resistance to Chloride Ion Stress Corrosion Cracking (SCC)
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Inconel 600, 625: Provides excellent resistance to high-temperature chlorine gas corrosion, suitable for anode leads, connections, and heating coils.
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Incoloy 825: Excellent resistance to chloride ions, sulfides, acids, and alkalis, ideal for mixed medium environments.
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Monel 400 (Nickel-Copper Alloy): Resistant to hydrofluoric acid, sodium hypochlorite, and chlorine gas, widely used in pumps, valves, flanges, and impellers.
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Electrical Conductivity of Nickel-Based Alloys in High-Load Current Environments
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Nickel-based alloys have significantly higher electrical conductivity than titanium, making them ideal for use in anode busbars, connectors, and conductive parts to avoid electrical losses and potential drift.
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Technological Barriers and Future Trends
| Material | Technological Barriers | Future Trends |
| Titanium and Titanium Alloys | High equipment manufacturing requirements, complex welding processes (argon arc, plasma welding) | Composite sheet technology (Steel-Titanium composite), Palladium-alloyed titanium for enhanced corrosion resistance |
| Nickel-Based Alloys | High raw material costs, difficult to process, welding requirements (prone to cracking) | Nanocrystalline nickel-based alloys (improving corrosion resistance), New Inconel X series alloys |
Case Studies and Applications
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In the industry, imported Japanese or European titanium composite plates are commonly used for electrolyzer shells (Q345 steel + Gr2 titanium liner).
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Anode busbars and conductive systems are typically made from Inconel 600 or Monel 400, depending on load levels.