Waste as a Resource
Lehigh Cement regards waste materials and by-products from other industries as valuable raw materials and fuels, which we use in manufacturing new products. By doing so, we are making an active contribution to waste management, recycling and the preservation of resources. Our use of alternative raw materials and fuels may also offset the use of virgin materials or help to supplement or replace fossil fuel energy sources in our processes.
Below is a list of alternative materials and fuels currently being used at Lehigh Hanson, Canada Region.
 Iron Slag/Ferrous Granules
This material represents a source of iron for both Edmonton and Delta cement plants. It is produced as a by-product from a metallurgical facility in Trail, BC. This waste material is used as an alternative to a virgin source of iron and diverts a usable waste material from entering a landfill.
Bottom Ash
Bottom Ash is a waste product of the coal-fired thermal generating power stations and is used as a supplemental silica source in the production of cement. It is formed when ash particles accumulate together, becoming too large to be carried from the furnace into the flue gas. It impinges on the walls or is collected in the ash hopper at the bottom of the furnace. The material is dark grey/black in colour and is either land filled or used as a fill material (typically in the remaining pits from the mining of coal). Lehigh Cement uses this material as a partial replacement to virgin clay due to its silica content and low alkalis.
Fly Ash
Fly Ash (like bottom ash) is a by-product of combustion from the coal-fired power plants. Fly Ash is finer and lighter than bottom ash and as such rises with the flue gas where it is collected by the power plant’s pollution abatement equipment (ESP or baghouse). Lehigh Cement makes use of this waste product as a partial clinker substitution and intergrinds the fly ash with cement to manufacture InterCem®. Utilizing the fly ash in this manner helps Lehigh Cement lower its Greenhouse Gas footprint associated with cement production. The creation of InterCem also helps downstream users of cement by creating a consistent product with a ‘pre-mixed’ quality, thereby freeing up storage requirements at the concrete production facility.
Recycled Concrete/Aggregates
Waste concrete is crushed, screened and reused as aggregate for bulk fills, bank protection, drainage structures and in new concrete pours where applicable.
Link to Portland Cement Association recycled aggregate page.
 Tire Derived Fuel
Waste tires are used as fuels, partially replacing the use of coal. The high heating values of waste tires helps to reduce the nitrogen dioxides (NOx) emissions at cement plants.
Commercial-Grade Contaminated Soil
This waste material is diverted from landfill when used in cement kilns as a partial replacement for shale feedstocks (raw material). The contamination is effectively and safely destroyed within the cement kiln and used in the production of cement.
Waste Iron Granules
Spent granules used in various media blasting (sand-blasting) operations can be used as an iron source in cement manufacturing. The use of this material diverts it from landfill while transforming it into a useable product component.
Pure Silica Geyserite
Geyserite is a reddish-coloured waste product from silica mining that is considered a contaminate for pure silica mining. The utilization of this material in cement plants reduces the amount of material that would otherwise be wasted or sent to the landfill. |
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