Intro
In Bayer alumina production, precise solid-liquid separation is essential for product quality, chemical efficiency, and operational stability. Traditional leaf filters often suffer from cloth wear, tearing, and high labor requirements, making reliable filtration a challenge.
Dongou Microfiltration systems provide high-precision, durable, and regenerable filtration solutions for each stage—including red mud washing, liquor clarification, and aluminum hydroxide separation—also supporting lithium recovery to enhance yield and economic efficiency.
Stage 1: Red Mud Washing & Separation
Challenge:
Post-digestion red mud slurry is viscous, abrasive, and uneven. Inefficient separation of entrained sodium aluminate causes alumina and caustic soda losses, increasing downstream processing costs.
Dongou Solution:
- High-Throughput Filtration Systems: Designed for effective flow and particle separation, our microporous filtration tubes ensure reliable red mud washing and maximize recovery of valuable sodium aluminate.
- Durable & Chemical-Resistant: Filters withstand high temperatures (up to 110°C), strong alkalinity, and abrasive solids for long-term stable operation.
- Continuous Stirring & Spraying: Inverted filtration tubes with internal stirring prevent cake buildup, ensuring uniform washing and preventing clogging.
- Minimized Reagent Loss: Efficient filtration preserves sodium aluminate solution, reducing soda consumption and improving plant economics.
Stage 2: Green/Spent Liquor Filtration & Lithium Adsorbent Separation
Challenge:
Pregnant or spent liquor contains colloidal silica, fine solids, and lithium-enriched aluminum hydroxide adsorbents. Their breakthrough can compromise crystal growth and reduce lithium recovery. Traditional leaf filters are prone to cloth wear, perforation, and high labor intensity.
Dongou Solution:
- 0.2 μm Precision Microfilters: Effectively separate fine solids and lithium adsorbents while maintaining high liquor clarity.
- Durable Filtration Tubes: Sintered high molecular weight polyethylene tubes resist strong alkali and high-temperature conditions, with long service life.
- Integrated Spraying & Continuous Stirring: Upper and lower filtration tubes work together, continuously washing filter surfaces and preventing filter cake accumulation.
- Regeneration Capability: Filters can be periodically chemically regenerated under strong alkali conditions, ensuring consistent performance with minimal downtime.
Stage 3: Aluminum Trihydrate Classification & Washing
Challenge:
Post-precipitation slurry requires seed separation and washing. Inefficient separation leads to uneven particle size, high residual soda, increased evaporation energy, and lower lithium recovery efficiency.
Dongou Solution:
- Custom-Configured Precision Microfilters: Separate fine seed from coarse product, optimizing aluminum hydroxide crystal growth and lithium adsorbent recovery.
- Efficient Washing & Recovery: Continuous filter operation with counter-current washing reduces water and chemical consumption, lowering operational costs.
- Mechanical Robustness: Equipment tolerates cyclic loading and abrasive solids, ensuring long-term reliability.
Stage 4: Spent Liquor Treatment & Purification
Challenge:
Circulating spent liquor accumulates impurities such as oxalates, sulfates, and fine solids, causing scaling in evaporators and reducing digestion efficiency.
Dongou Solution:
- Side-Stream Microfiltration: Continuous removal of sub-micron impurities keeps circulating liquor clean, protecting evaporators and overall process stability.
- Chemical and Physical Durability: Filtration tubes resist strong alkali, acids, and salts.
- Improved Plant Stability: Reduces scaling, extends maintenance cycles, and enhances thermal efficiency across the evaporation system.
Innovation Highlights
- High molecular weight polyethylene sintered filtration tubes.
- Filter elements withstand high temperature (110°C) and strong alkalinity.
- Inverted filtration tubes with internal stirring prevent cake buildup.
- Tubes withstand high-frequency, high-pressure air-liquid backflushing.
- Periodic strong-alkali chemical regeneration extends filter life.
- Long-life, stable, high-precision, high-throughput filtration.
Why Dongou Filters?
Custom Engineering: Lab sample analysis and pilot-scale testing ensure the optimal filter selection for each Bayer process stage and lithium recovery application.
Integrated Systems: Skid-mounted, PLC-controlled units with piping and platforms enable rapid installation and seamless commissioning.
Sustainable Productivity: Precision filtration across all process stages reduces chemical consumption, enhances product quality, and ensures operational stability.
Contact us today to request a customized purification network for your Bayer process alumina production.