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Portland Cement Production That Uses Ash Left After Solid Waste Is Burned

Recycles Unwanted Garbage Residue and Reduces Costs of Cement Production

This Portland cement manufacturing system reliably integrates the bottom ash remaining after municipal solid waste incineration as a component in the raw kiln feed. The world produces more than 2 billion metric tons of municipal solid waste each year. In the United States, most solid waste is added to landfills. In some instances, solid waste is incinerated instead; while incineration greatly reduces waste volume, 20-35 percent of its weight remains as bottom ash. Recycling the bottom ash as material for cement production is attainable and would be a profitable means of reducing global waste. Replacing even up to 5 percent of Portland cement raw materials with incineration ash would significantly offset costs of global cement production and waste management.

Researchers at the University of Florida have developed a procedure for creating Portland cement that incorporates the world’s abundant supply of waste incineration ash as an input material. The process is an economically viable way to recycle bottom ash that reduces the environmental impact of both municipal solid waste incineration and cement manufacturing.



A system for manufacturing Portland cement, which incorporates ash from municipal solid waste incineration as a raw ingredient in the kiln feed.



  • Recycles bottom ash as material in cement kiln feed, reducing landfill waste produced by solid waste incineration plants
  • Reduces necessity of mining for raw kiln materials, saving cement manufacturers money and lowering their environmental impact
  • Decreases amount of landfilling, cutting costs for municipal solid waste incineration facilities
  • Kiln design and operation is very similar to that of a conventional kiln, enabling a smooth transition to using recycled incineration ash
  • New kiln feed composition enables lower carbon dioxide emissions, providing environmental benefits


This Portland cement manufacturing system enables use of municipal solid waste bottom ash in the cement kiln feed. Bottom ash is a safer alternative to other potential cement kiln ingredients such as fly ash, which has detrimental metal leaching properties. The system can replace up to 5 percent of the raw kiln feed with recycled bottom ash. The kiln feed containing the bottom ash forms ash-amended clinker, which when ground mixes to prepare cement products comparable to normal Portland cement products.

Patent Information: