Lime Helps to Limit the Environmental Impacts of Steelmaking

Wastewater

Lime is the most available and cost-effective neutralizing agent among all alkali materials that treats wastewater. It can neutralize many organic and inorganic pollutants, including heavy metals and fluorine, and it meets the requirements for pH adjustments necessary for discharge from steel mills.

Carmeuse has extensive experience in chemical processes to treat wastewater from a variety of industrial sectors. Our solutions can help minimize costs while conforming to strict environmental standards for purified water not only in North American, but also throughout the world.

Residual Sludge and Solid Waste

Lime neutralizes free acids in chemical waste products and forms insoluble, chemically stable salts that are safe from leaching into the environment. Lime reacts with active silica/alumina in mineral sludge to stabilize the materials and form a solid and low-permeable matrix, contributing to the blocking of leaching contaminants. The use of quicklime helps dry and solidify sludge for final disposal or reuse; and lime-based binders provide highly permeable properties to solidified sludge and stabilized waste, keeping them safe from leaching contaminants.

Carmeuse’s lime products can be used in customized solutions for various types of sludge or waste disposal, particularly depending on the end reuse such as fertilizers. We offer lime products and binders that fit all types of processes to treat specific waste generated by the iron and steel industry.

Flue Gas Cleaning

Lime enables manufacturers to comply with regulations on emission levels. Its use provides customized flue gas cleaning solutions based on variable processes including sinter plants, coke oven, boilers and more, all of which have their own specifications and requirements.

Emissions levels for steel mills vary greatly. Carmeuse helps companies carefully evaluate the flue gas cleaning process and develop the best and most cost-effective solutions available for them.

Lime vs. Caustic Soda

Lime isn’t the only compound used in the steelmaking process to help mitigate environmental impacts. Caustic soda is also used. However, lime offers a multitude of advantages, both in terms of ease of use and efficiency, because it:

Is not as hazardous as caustic soda
Is the most economically favorable alkaline reagent for acid neutralization, pH adjustment and removal of metals
Neutralizes more quickly and completely
Has a slower reaction time than caustic soda, allowing for better control
Offers a stronger base than caustic soda
Is delivered dry, therefore the end user does not pay for water content
Creates a sludge that is low volume and easy to handle
Has a pH range that is optimal for metals removal
Does not freeze

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