Waste to Resource: Coal Fly Ash Beneficiation

Dimitrios Kakaris Porter, and Dr. Timothy Dittrich, Department of Civil and Environmental Engineering, Wayne State University, 42 W. Warren Ave., Detroit MI 48202

In 2018, the United States was the third largest consumer of coal, incinerating 624 mega tons of coal in power plants. When coal is combusted, about 10% of the mass is left behind as metals and minerals in a waste product called coal combustion residuals (CCR). This waste is generally hauled to landfills, which impacts our economy and environment by taking space and resources in order to dispose of it. A large portion of the ash consists of minerals such as silica dioxide and various clays, which under the right conditions can be a valuable resource.  Each ton of CCR also has ~$300 of value in critical metals known as rare earth elements (REEs). The goal of my project is to economically utilize the CCR for beneficial reuse, including recovering metals and using the mineral content for things such as concrete aggregate. The issue with directly reusing CCR in concrete is that it also contains potentially harmful metals (e.g., Hg, As) that can lead to unpredictable outcomes such as metal leaching into the environment. The purpose of this research is to process CCR sequentially so that benefits are maximized, and economic and environmental costs are minimized. The ash is first subjected to a magnetic separation to separate about 10%wt of the material, presumed to contain mostly iron. Next, the ash will be hydrothermally treated and then acidified for REE extraction. The remaining ash will undergo a purification phase and be tested for use in concrete. The concrete samples will then be subject to leaching experiments using established ASTM standards. The expectation is that useful metals can be extracted, and harmful concrete leachate can be reduced. This research will provide insight to the processes that can turn this costly waste into a productive resource. 

Additional Abstract Information

Presenter: Dimitrios Kakaris Porter

Institution: Wayne State University

Type: Poster

Subject: Civil Engineering

Status: Approved

Time and Location

Session: Poster 4
Date/Time: Tue 11:00am-12:00pm
Session Number: 3629