Coal ash utilisation: Turning waste into resources

The coal mining industry has been around for generations, but today’s operations are vastly different than sending men with a bird, pickaxe, hammers, and chisels into the mines to chip off pieces of sedimentary rock. One concern with modern coal mining is the waste left behind from the burning of fossil fuels by industry and power plants, such as coal ash.

Why should professionals in the coal and power industries worry about coal ash?

Coal ash is made up of various components, such as bottom ash, boiler slag, fly ash, and flue gas desulfurisation material. It contains heavy metals, such as arsenic, lead, selenium, and mercury, which must be handled properly to avoid contaminating the environment. Repurposing and properly handling power industry waste prevents issues such as contaminated groundwater and air quality issues.

Ways to repurpose coal ash

Most commonly, fly ash is used for concrete and cement production because it is fine and powdery. Bottom ash is coarser and used as fill material. Currently, a mere 10% of coal ash is reused, but there are many opportunities to repurpose the by-products, such as:

Construction and infrastructure projects

Fly ash is an ingredient used in green concrete. The ash increases the material’s strength and longevity so it can be used as a lighter-weight alternative to traditional concrete, but still durable enough for roads and fill material.

Agricultural improvements

Coal ash is sometimes used to improve soil because it adds nutrients and retains water in droughts. However, companies must work closely with an energy consultant, set goals, follow regulations and be cautious about heavy metal contamination. Hiring an energy consultant can save a business money and ensure leadership meets its goals.

Filler for mines and under pipes

Bottom ash is coarse and may be used in place of materials such as pea gravel. Utility companies laying pipes for water or sewers might use coal ash as a stabiliser before laying the pipes on the ground.

Some people use coal ash to fill in old, abandoned mines to prevent weakness in the ground above and avoid sinkholes.

Manufacturing

One use of FGD gypsum is to create drywall. It works in place of mined gypsum. Factories press the FGD between paper layers for each drywall panel. The sustainability factor increases because waste materials get reused and the need for new gypsum mining is reduced.

The FGD gypsum must be processed to remove any toxic materials. The Environmental Protection Agency has numerous regulations regarding the storage of coal ash, whether for disposal or reuse.

Changing the trajectory of coal ash

Those in the coal industry and power production often face public backlash about the potential contamination of nearby water sources. However, as more plants find ways to utilise waste materials in positive ways, public perception is improving. Taking the time to educate the public about coal ash and gain its support for a more sustainable process is key to increasing reuse and reducing environmental impact.

Author bio

Jane Marsh is a seasoned environmental journalist and the Editor-in-Chief of Environment.co, specialising in in-depth coverage of environmental trends, sustainability, and the evolving energy landscape. With her work featured on leading platforms like Renewable Energy Magazine, Manufacturing.net, and Nation of Change, Jane brings a keen perspective on the intersection of energy innovation and industry practices.

Read the article online at: https://www.worldcoal.com/power/23122024/coal-ash-utilisation-turning-waste-into-resources/