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Coal Ash Solutions

Astec Industries is a leading manufacturer of equipment and solutions for infrastructure development. Astec provides advanced process control and thermal treatment technologies that support materials beneficiation in the coal ash industry. With expert engineering, comprehensive services, and robust digital tools, Astec helps end users improve operational efficiency while achieving sustainable, cost‑effective performance.

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Coal Ash Beneficiation System

The system provides a method for improving the quality of coal ash by integrating drying, particle sizing, and carbon reduction into a continuous beneficiation process. The technology uses controlled heat, air classification, and staged carbon removal to produce a consistent, low‑carbon, properly sized coal ash suitable for use in concrete and other applications, while maximizing energy efficiency through heat recovery and closed‑loop material handling.

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coal ash plant layout render with no background

1

Moist fly ash is loaded into a bin, metered onto a conveyor, screened to remove oversized material, and recycled as needed to ensure consistent feed quality.

2

Screened material enters a rotary dryer where moisture is removed using recovered process heat, producing a stable, low moisture feed for classification.

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An air classifier separates particles to meet ASTM size requirements with oversized material milled and returned in a closed-loop to maintain uniform particle size.

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Sized fly ash passes through sequential carbon-reduction drums (as needed) where controlled combustion lowers LOI to target levels before cooling and storage.

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Heat recovery and closed-loop handling maximize energy efficiency while producing a dry, properly sized, low-carbon fly ash suitable for beneficial use.

Our proven technology and commitment to client satisfaction ensure optimal performance and a successful transition to coal ash utilization. Contact Astec today to discuss your coal ash beneficiation needs and explore how our industry-leading solutions can benefit your operation.

Coal Ash
Beneficiation Process

The coal ash beneficiation system is designed to convert high‑moisture, carbon‑laden coal ash into a dry, ASTM‑compliant material suitable for commercial use. The process integrates drying, classification, milled, and staged carbon reduction, supported by an energy‑efficient heat‑recovery configuration.

The process begins with ambient‑temperature coal ash (approximately 20% moisture) loaded into a cold‑material feed bin. Material is metered onto an inclined conveyor and delivered to a scalping screen. Oversized material is routed through a clod breaker and recycled, while acceptable material proceeds to the drying stage. Load sensors on the transfer conveyor support process control and inventory management.

Wet coal ash enters a parallel‑flow rotary dryer, where moisture is removed using heat recovered from downstream carbon‑reduction drums. A supplemental burner provides backup heat when needed. Dried material is combined with baghouse‑collected fines before entering the classification system.

The air classifier separates particles based on ASTM C618 size requirements. Conforming particles are captured in a secondary baghouse, while oversized particles are directed to a ball mill for size reduction and then returned to the classifier. This closed‑loop system ensures consistent particle size distribution.

Sized, carbon‑laden fly ash is conveyed to a feed silo and introduced into the initial carbon‑reduction drum, where controlled combustion removes a portion of the carbon content. The partially treated ash is then transferred to subsequent feed silos and processed through additional carbon‑reduction drums as needed to achieve the desired final carbon level. After the final reduction stage, the material is cooled and conveyed to storage or loaded into pneumatic trailers or railcars.

Exhaust gases from the carbon‑reduction drums are combined and routed to the rotary dryer inlet. This configuration links all drums and significantly reduces process fuel consumption, improving overall process efficiency.

The system produces a dry, properly sized, carbon‑reduced coal ash suitable for beneficial reuse while maximizing energy efficiency through integrated heat recovery and closed‑loop material handling.

One Technology Many Industries

Our engineering team works with customers across each of these industries to understand their specific material characteristics, throughput requirements, and regulatory constraints — then designs a system that meets those needs precisely. No off-the-shelf solutions. Every system is engineered to order.

  • Coal Ash & Fly Ash Beneficiation
  • Wastewater Biosolids
  • Industrial & Frac Sand
  • Minerals & Aggregates
  • Soil Remediation
  • Drill Cuttings & Oilfield Waste
  • Biomass & Wood Waste
  • Fertilizer & Compost
  • Animal Bedding
Discuss Your Application

Our rotary drying technology now processes biosolids at municipal wastewater facilities. These systems reduce waste volume and support sustainable biosolids management, showcasing the environmental and cross‑industry versatility of our core technology.

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Kevin Risley

Director of Sales Engineering
1.423.413.7987
[email protected]

Aaron Schoolfield

Sales Development
1.423.551.0550
[email protected]