The Critical Role of Stainless Steel in Lithium Production

Lithium producers face mounting pressure to scale operations quickly and efficiently as the electric vehicle revolution accelerates and global energy storage demands surge.

For procurement engineers and project managers overseeing these critical facilities, selecting suitable materials for process piping systems can mean the difference between consistent production and costly shutdowns.

This article explores the specific challenges of both primary lithium extraction methods and provides detailed material recommendations backed by real-world applications.

Learn which stainless steel grades excel in different environments, understand their practical limitations, and gain valuable insights for working effectively with corrosion engineers to optimize your stainless steel piping systems.

Understanding Lithium Extraction Methods

Brine Mining Process

The process begins with careful geological surveys to identify suitable brine aquifers. 

Once located, wells are drilled and fitted with specialized pumping systems designed to handle the corrosive nature of the brine. 

The extracted brine undergoes a series of concentration steps, where solar evaporation gradually increases lithium concentrations from less than 0.2% to approximately 6%.

During this process, various compounds precipitate out in a specific sequence: first sodium chloride, then potassium chloride, and finally magnesium chloride, leaving a concentrated lithium solution.

The final stages involve chemical treatment with sodium carbonate to precipitate lithium carbonate, followed by filtration and purification to achieve battery-grade lithium compounds. 

While energy-efficient due to its reliance on solar evaporation, this method faces increasing scrutiny due to its extensive water consumption and potential impact on local ecosystems.

Hard Rock Mining Process

The process involves several critical stages. 

Initially, the mined spodumene ore (1 to 4% lithium oxide on average) undergoes primary crushing to reduce large rocks to manageable sizes, typically less than 15cm. 

Secondary and tertiary crushing further reduces particle size before ball mills grind the material to a fine powder.

The powder enters a flotation circuit where air bubbles and specialized chemicals separate lithium-bearing minerals from waste rock.

The concentrated ore then moves to the conversion process, where it's heated in rotary kilns to temperatures in excess of 1100°C to transform the crystal structure, making it more reactive to chemical treatment.

After cooling, the material is mixed with sulfuric acid and roasted again, converting lithium into a water-soluble form. 

The resulting solution undergoes multiple purification steps, including filtration, precipitation, and ion exchange, to remove impurities before final processing into battery-grade lithium compounds.

Optimal Stainless Steel Alloys for Brine Mining

316L Stainless Steel

316L stainless steel effectively handles sodium chloride concentrations up to 26%. Its molybdenum content helps prevent pitting corrosion, while low carbon levels reduce corrosion risk during high-temperature welding. 

This makes it perfect for general piping systems where chemical exposure is constant but not extreme.

2205 Duplex

2205 duplex stainless steel provides twice the strength of standard grades, allowing thinner pipe walls in high-pressure applications. 

This results in roughly 20% material cost savings while maintaining excellent resistance to chloride-induced corrosion, making it particularly valuable in high-pressure brine transport systems.

904L

The high nickel and molybdenum content in 904L creates superior resistance to reducing and oxidizing acids. This makes it ideal for handling complex chemical mixtures in lithium precipitation, including concentrated lime and soda ash solutions. 

It's the preferred choice for areas with extreme chemical exposure.

Optimal Stainless Steel Alloys for Hard Rock Mining

Hastelloy C-276

Hastelloy C-276 excels in sulfuric acid environments up to 250°C. Its unique composition protects against stress corrosion cracking and pitting, making it essential for acid leaching circuits.

This alloy maintains its integrity even under the most demanding conditions.

2205 Duplex

In hard rock processing, 2205 duplex stainless steel handles slurries containing up to 50% solids while maintaining structural integrity.

Its strength and corrosion resistance makes it particularly effective in pumping and transport systems where abrasion is a significant concern.

316L

316L performs effectively in auxiliary systems operating below 60°C with moderate acid concentrations.

It provides a cost-effective solution for water handling, cooling systems, and general process piping where conditions are less severe.

This makes it an economical choice for many supporting operations.

The Importance of Engineering Expertise in Designing Lithium Extraction Systems

The complexity of lithium extraction facilities demands a sophisticated approach to material selection and system design.

Corrosion engineers play a pivotal role in analyzing the intricate chemical and mechanical environments present throughout these operations.

Their expertise helps facilities avoid costly failures while optimizing capital expenditure on materials.

Material Selection Process

Corrosion engineers develop detailed corrosion curves for each facility's unique chemical environment.

These technical roadmaps guide material selection based on operating temperatures, chemical concentrations, and pressure requirements.

The analysis extends beyond simple chemical resistance to include factors like erosion from slurries, thermal cycling stress, and mechanical loads.

Total Cost of Ownership Analysis

While premium alloys like Hastelloy C-276 and 904L stainless steel carry higher initial costs, they often deliver superior long-term value through:

• Extended equipment lifespan
• Reduced maintenance frequency
• Lower risk of catastrophic failure
• Minimized production interruptions
• Decreased replacement part inventory

System Design Optimization

Engineering expertise ensures that piping systems are designed not just for chemical compatibility but also for:

• Optimal flow characteristics to minimize erosion
• Sufficient access points for inspection and maintenance
• Strategic material transitions to reduce galvanic corrosion
• Proper support and flexibility for thermal expansion
• Enhanced reliability in critical process areas

Risk Mitigation Strategies

Experienced corrosion engineers help facilities develop comprehensive monitoring and maintenance programs. 

These programs typically include regular thickness testing, corrosion coupon analysis, and predictive maintenance schedules tailored to specific equipment and operating conditions. 

This proactive approach helps prevent unexpected failures and extends the system’s lifetime.

Lithium producers can leverage engineering expertise during the design phase to create robust, efficient systems that balance performance requirements with economic constraints. 

This investment in technical knowledge pays dividends throughout the facility's operational life through reduced maintenance costs and improved system reliability.

Conclusion

The lithium industry continues to evolve, with emerging extraction technologies that may require specialized materials. 

Staying informed about materials developments and maintaining relationships with qualified corrosion engineers and suppliers ensures optimal system performance as technology advances.

Procurement engineers should keep detailed records of material performance in their applications, as this data proves invaluable for future expansion projects and system upgrades.

Regular consultation with metallurgists and corrosion specialists helps ensure that material selections remain optimal as processes evolve and production demands increase.

If you’re looking for an experienced, dependable source of stainless steel for your lithium extraction or processing projects, contact the analysts at Unified Alloys today.

With decades of experience serving industries of all sizes throughout North America and Canada, we have the knowledge and selection to help you achieve your production goals.

References:

• New Castle Stainless Plate: Lithium Close Up [PDF]
• Lithium Harvest: Lithium Extraction Methods
• Springer Nature Link: The Corrosion of Metals by Molten Lithium
• The International Journal of Electrochemical Science: A Comparative Study on the Corrosion Behavior of 316L and 304 Stainless Steels in a Simulated Alkaline Environment for Lithium Extraction [PDF]
• Special Piping Materials: An Update on the Lithium Market
• Special Piping Materials: Stainless Steel and the Mining Industry
• California Energy Commission: Pilot Scale Recovery of Lithium from Geothermal Brines [PDF]
• Piedmont Lithium: Lithium 101