A PROPOSAL TO COMMERCIALIZE A SINTERED COAL ASH/FLUX MATERIAL FOR BUILDING PANELS

A PROPOSAL TO COMMERCIALIZE A SINTERED COAL ASH/FLUX MATERIAL FOR BUILDING PANELS

00-1/3.1B-1

Dry

University of Illinois at Urbana-Champaign

Illinois coal ash from the power plant at Little Egypt, owned by the Southern Illinois Power Cooperative in Marion, has heavy metals and is considered a difficult waste for disposal. In our process it has tremendous potential because of its high iron and metal content. Iron can provide a variety of colors while the heavy metals can be sequestered inside the panels.

Project Objectives And Technical Approach
The project objective was to develop commercially viable building products using Illinois coal ash. The technical approaches to achieving this objective were:

• to demonstrate the feasibility of sequestering ash metals in a value added product with competitive structural, insulative, density, water absorption and color properties.
• to study the microstructure to optimize the performance parameters of strength, density, water resistance and insulative properties. (Microstructure is the small scale internal makeup of a material which has certain physical properties which affect the larger scale performance characteristics.)
• to optimize the production parameters at the industrial facility to produce these panels.
• to develop a business plan to commercialize the product.

The commercial implementation plan required first developing a viable panel in the laboratory and then proceeding to develop the manufacturing conditions for the industrial partner's plant. The tasks were:

• to demonstrate the feasibility of sequestering ash metals in a value added product with competitive structural, insulative, weight, water absorption and color properties.
• to refine the microstructure in order to optimize the performance parameters of strength, density, water resistance and insulative properties.
• to optimize the production parameters at the industrial facility.

Fifteen large panels, four feet by eight feet by six inches were produced at the industrial facility and numerous smaller samples in the lab; including three 1'x1'x6" blocks. The parameters investigated at the industrial facility included refinement of the molds, addition of inexpensive fibers to reduce drying shrinkage, and pressing the panels, rather than mixing to reduce water use. Lab studies included loss on ignition of the ash correlated with strength data, and thermographic analysis measured interior heat soak rates and heating regimes.

The main findings were:

• Large panels without cracks can be manufactured in the factory.
• Addition of fibers reduces drying shrinkage cracks.
• The amount of carbon in the ash affects the strength - the more carbon, the weaker the product. A higher carbon content in the ash requires more water for mixing, producing a weaker panel.
• There is no problem in heating and sintering all the way through panels which contain metal chases; panels without such chases take longer to heat and sinter through their depth.
• Heating to above the critical 200°C in a moist chamber eliminates surface spalling.

The uncompleted technical goals are:

• To investigate the vacuum sintering of Illinois coal ash for other panels. This was not done because the industrial partner did not have a vacuum furnace available.
• To develop a business plan to commercialize the product.

11/1/2000

7/31/2002

2000