Zinc-Containing Dust Ash Collector in Steel Plants

In steel production, especially during sintering, electric arc furnace (EAF) smelting, and secondary metallurgy processes, significant volumes of flue gas are generated containing fine particulate matter, among which zinc and its compounds are prevalent. These zinc-containing dusts, if not properly captured, not only contribute to environmental pollution but also pose operational challenges, such as equipment corrosion and material buildup in ducts.

To address these challenges, baghouse dust collectors with optimized filtration configurations are widely implemented. These collectors operate under high-temperature and chemically aggressive environments, requiring careful selection of filter materials and system design.

Sources of Zinc-Containing Dust

Zinc enters the steel production process primarily through:

• Use of galvanized scrap in electric arc furnaces.
• Addition of zinc-bearing materials in sintering and pelletizing.
• Surface coatings or residues on recycled input materials.

During thermal processing, zinc vaporizes and later recondenses as fine particles (ZnO, ZnFe₂O₄, etc.), often smaller than 1 μm, making them difficult to capture using coarse mechanical separation methods alone.

Key Requirements for the Dust Collector

1. High Filtration Efficiency
   Due to the sub-micron size of zinc particles, filter bags must maintain high collection efficiency—often exceeding 99.9%—to comply with environmental regulations and ensure recovery potential.
2. Temperature Resistance
   Depending on the flue gas origin, operating temperatures can reach 200–260 °C. Filter media like PTFE membrane laminated glass fiber or aramid blends are commonly used.
3. Chemical Compatibility
   Zinc dust often coexists with acidic gases (e.g., SO₂, HCl). Filter materials must resist acid attack and hydrolysis, especially under high humidity.
4. Dust Recovery & Reuse Potential
   Collected zinc-containing dust is frequently sent for recycling to recover valuable zinc. The design must allow for clean, dry dust discharge and minimized contamination with other materials.
5. Maintenance Access & Online Cleaning
   Pulse-jet baghouse systems are often preferred for their effective cleaning performance. Online pulse cleaning ensures continuous operation without the need to shut down the system.

Suitable Filter Bag Materials

Operational Considerations

• Dust load: High dust concentration may require pre-separation or multi-stage filtration to protect the main filter.
• Condensation risk: Proper insulation and gas temperature control prevent zinc chlorides from condensing, which can cause corrosion and clogging.
• Explosion hazard: Zinc dust is potentially combustible. Proper grounding, anti-static filter bags, and explosion vents are necessary safety features.

This type of dust collector system plays a dual role—pollution control and zinc recovery—within integrated steel plants and EAF mini mills. It supports both environmental compliance and material circularity in metallurgical operations.