Electric Arc Furnace

Steel Making Process Applications

Electric Arc Furnace Lime Injection Systems for Foamy Slag Coagulation & Improved Environmental - Operational Benefits

Equipment & Technology Offered: Bulk Storage Silos (Welded or Bolted) and Metering System Pneumatic Dilute Phase Conveying System Injection Lances and Flexible Hoses PLC based Electrical Control Systems Can be added to Existing Lime Silos Custom Lime Batch Additions per Melt Yields a Cleaner, Safer Melt Shop
Photo: Dolomitic & High Calcium Blending & Dilute Phase Injection

Although Lime has been added to EAF style furnaces for decades, it has only been in the last 15 years that an efficient method was found to introduce the Lime to the melt through a sidewall panel in the furnace.  In the past Lime was added to the furnace directly by a mechanical screw via a fifth hole in the roof using a pipe or sometimes adding a whole supersack of lime. This method of mechanical dosing was messy, with lime fines being blown around the shop floor by the intense heat. With this method, the lime was not evenly distributed within the furnace and a large portion of lime ended up in the baghouse of the dust collection system.

The new Lime Injection technology transfers the Lime by pneumatic conveying from a pressurized system directly to the injector / lance system within the melt of the furnace. This new Injection technology allows for the recycling of waste bag house lime and waste process brick which reduces the facilities' disposal costs. The more efficient distribution of the Lime into the furnace results in a reduction of Lime consumption of 10% or higher. Additionally this process improvement yields a cleaner, safer shop environment, reduced costs of maintenance to the materials handling system. This pneumatic transfer system also allows the steelmaker the flexibility to blend various combinations of Dolomitic Lime and High Calcium Lime to the custom needs of the process. This ultimately reduces the cost of the Lime consumed in the process.

Dilute Phase or Dense Phase Pneumatic Conveying and bulk storage systems are utilized in this technology depending upon the particle size of Lime to be administered to the process.

In order for these types of installations to be successful, it is critical that the correct equipment design be considered based on the bulk handling and flow characteristics of the various grades of Lime. Expertise for these types of systems is only acquired through experience with the various Lime materials over a broad range of operating conditions.