Steel Smelting
Air-Suspension Blowers Optimize Slag Processing and Desulfurization in Steelmaking
A large integrated steel mill in Shandong, China, producing over 3 million tons of crude steel annually, faced critical inefficiencies in its steelmaking process. Two major operations consumed excessive energy and posed safety risks: the ”air-quenching (wind quenching)” treatment of liquid steel slag and the ”flue gas desulfurization (FGD)” system for sintering exhaust. The plant’s legacy system relied on oil-lubricated Roots blowers and multi-stage centrifugal units, which consumed over 15% of total plant electricity, generated noise above 100 dB, and risked oil carryover that could contaminate by-products . To reduce operating costs and improve workplace safety, the mill replaced 16 conventional blowers with an integrated system of ”air-suspension centrifugal blowers” featuring air-foil bearings and high-speed permanent magnet motors.
”1. Wind Quenching for Steel Slag Granulation”
In the slag processing yard, molten slag at ~1,500°C was poured into a flow channel. High-velocity air from the air-suspension blowers, directed through precision air knives, atomized the liquid slag into spherical solid particles. The oil-free, high-pressure air (up to 80 kPa) provided strong oxidation, enabling effective separation of metallic iron from slag—a critical step for scrap recovery . Previously, water quenching posed explosion risks and generated polluted wastewater, while natural cooling took over 48 hours and created large glassy masses difficult to handle .
”2. Desulfurization Oxidation”
In the sinter plant, the blowers supplied oxidation air to the wet FGD tower, converting calcium sulfite into commercial-grade gypsum. The VFD-equipped blowers enabled precise, stepless airflow adjustment to match fluctuating SO₂ loads, ensuring stable desulfurization efficiency without clogging .
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Result
After 12 months of operation, the mill achieved:
Energy Savings:
System-wide power consumption dropped by over ”30%”, saving approximately 4.2 million kWh annually, equivalent to ~$250,000 USD in electricity costs.
Safety & By-Product Quality:
Air-quenched slag formed uniform 2mm spherical particles, eliminating explosion hazards and wastewater treatment. The dry process simplified downstream magnetic separation, recovering more scrap iron . Noise levels in the blower room dropped from >100 dB to below ”80 dB”.
Maintenance Reduction:
Oil-free operation eliminated lubricant costs and routine bearing replacements, reducing maintenance expenses by over ”60%” and enabling unattended, remote operation.
Conclusion
This case demonstrates that air-suspension blowers offer a reliable, high-efficiency solution for steelmaking’s most demanding applications. By replacing oil-lubricated equipment, the mill cut energy costs, enhanced by-product value, and improved both environmental compliance and worker safety, achieving a payback period of under 18 months.
