Stainless Steel External Coil Tube for Lithium Precipitation Reactor

Product Overview

The Stainless Steel External Coil Tube (Model: JX-CT-487) is a precision-engineered heat transfer component manufactured by Wenzhou Jixing Metal Materials Co., Ltd. Specifically designed for integration into high-efficiency settling external coil lithium precipitation reactors (沉锂釜), this coil tube serves as the primary thermal exchange medium within lithium-ion battery precursor manufacturing processes. The product is engineered to facilitate efficient heat dissipation and thermal regulation during the lithium carbonate precipitation reaction, ensuring optimal crystallization conditions for battery-grade lithium carbonate production.

This coil tube system represents a critical component in the advanced lithium refining supply chain, providing superior heat transfer performance while maintaining material integrity under harsh alkaline and high-temperature operating environments.

Material & Properties

Base Material

Key Mechanical Properties

Specifications

Parameter Specification Standard / Tolerance
Outer Diameter (OD) Φ19.0 mm / Φ25.4 mm / Φ33.7 mm ±0.15 mm (ASME B36.19M)
Wall Thickness 1.65 mm / 2.11 mm / 2.87 mm ±10% of nominal
Coil Length (per spool) 15 m – 120 m (configurable) ±0.5%
Bending Radius (minimum) ≥3.0 × OD ASME B31.3
Surface Finish Ra ≤ 0.8 μm (electropolished / passivated) ASTM A967 / AMS 2700
Pressure Rating (design) Up to 1.6 MPa (232 psi) @ 200°C EN 13480-3
Heat Transfer Efficiency ≥92% (compared to flat-plate baseline) Internal testing protocol
Welding Method Orbital TIG (GTAW) / Argon arc welding ASME IX, AWS D10.9
End Connection Flanged / Threaded / Socket-weld ASME B16.5 / B1.20.1
Coating (optional) PTFE-lined / Ceramic-coated inner surface ASTM B148
Maximum Operating Pressure 2.5 MPa (363 psi) Hydrostatic test at 1.5× design pressure
Service Life (design) ≥15 years under standard operating conditions Accelerated corrosion testing validated

Manufacturing Process

1. Raw Material Selection & Inspection

Virgin stainless steel seamless tubes are sourced from certified mills meeting ASTM A213 / EN 10216-5 specifications. Incoming material undergoes 100% chemical composition analysis (spectrographic), mechanical property verification, and ultrasonic flaw detection (UT) per ASTM E271.

2. Coil Forming & Cold Bending

The straight tube segments are fed through precision hydraulic coiling machines to form the external coil geometry. Cold bending is performed at ambient temperature to maintain the austenitic microstructure. The bending process is controlled to prevent localized strain hardening, with a minimum bend radius of 3.0 × OD to avoid wall thinning exceeding 10%.

3. Welding & Joining

All longitudinal and circumferential welds are executed using automated orbital TIG (Tungsten Inert Gas) welding with pure argon shielding gas (purity ≥99.995%). Back-purging with argon prevents internal oxidation. Weld parameters are controlled to maintain heat input below 2.5 kJ/mm to prevent sensitization. Post-weld inspection includes:

4. Solution Annealing & Pickling

The completed coil assembly undergoes solution annealing at 1050°C ± 25°C followed by rapid water quenching to restore full austenitic structure and eliminate residual stresses. Subsequent pickling removes oxide scale using a nitric-hydrofluoric acid solution, followed by passivation per ASTM A967 to establish a chromium-rich passive film thickness of ≥5 nm.

5. Surface Finishing

For applications requiring ultra-clean surfaces (lithium carbonate crystallization), the internal bore receives electropolishing treatment to achieve a surface roughness of Ra ≤ 0.4 μm, eliminating crevices where lithium salts could accumulate. This process also enhances the passive film uniformity and corrosion resistance by up to 3× compared to mechanical polishing.

6. Final Assembly & Testing

Each coil tube assembly undergoes hydrostatic pressure testing at 1.5 × design pressure (3.75 MPa) with a minimum hold time of 30 minutes. Dimensional verification is performed using laser scanning and coordinate measuring machines (CMM). Final product is packaged in protective moisture-barrier wrapping with desiccant packs for shipment.

Applications

Primary Application: Lithium Carbonate Precipitation Reactors

The JX-CT-487 external coil tube is purpose-engineered for integration into the High-Efficiency Settling External Coil Lithium Precipitation Kettle (高效沉降外盘管式沉锂釜). In this system, the coil tube functions as the external heat exchanger, removing reaction heat generated during the precipitation of lithium carbonate from lithium hydroxide and sodium carbonate solutions. Key application parameters include:

Secondary Applications

Quality Certifications & Compliance

Manufacturing Certifications

Product Standards Compliance

Testing & Verification Reports

Unique Selling Points

1. Purpose-Engineered for Lithium Chemistry: Unlike generic stainless steel coils, the JX-CT-487 is specifically designed for the unique corrosive environment of lithium precipitation reactors, with material selection and surface treatment optimized for lithium hydroxide and carbonate media.

2. Superior Heat Transfer Performance: The optimized coil geometry and internal surface finish deliver ≥92% heat transfer efficiency, enabling faster precipitation kinetics and higher throughput in lithium carbonate production.

3. Ultra-Clean Internal Surface: Electropolished interior (Ra ≤ 0.4 μm) prevents lithium salt deposition and product contamination, critical for maintaining battery-grade purity specifications.

4. Extended Service Life: Solution-annealed, passivated, and optionally PTFE-lined configurations provide design life exceeding 15 years, significantly reducing maintenance intervals and total cost of ownership.

5. Full Traceability: Every coil tube assembly is serialized with complete material traceability from mill heat number through final testing, meeting the stringent quality documentation requirements of the battery materials supply chain.