The Use of Sludge Generated by the Neutralization of Acid Mine Drainage in the Cement Industry

The goal of this proposed study is to demonstrate the use of acid mine drainage (AMD) treatment sludge in the manufacture of Portland cement. Portland cement is composed of a mixture of calcium, silicon, aluminum, and iron oxides. When AMD is neutralized, sludge is precipitated that is composed largely of calcium, iron, and aluminum hydroxides. Disposal of this AMD treatment sludge is an economic burden that consumes resources that could otherwise be used to construct new treatment facilities. The successful completion of this project will result in the establishment of a process that will provide the cement industry with an economic source of calcium, aluminum, and iron while at the same time reducing the costs at AMD treatment facilities. This project will demonstrate the use of AMD treatment sludge from the Pennsylvania Department of Environmental Protection’s Rausch Creek treatment facility to manufacture Portland cement at Lehigh Cement’s Evansville plant. Once this process is successfully established, it can be used as a model for application at other cement and treatment facilities. The utility of this process is not limited to the eastern coal fields. The potential of using this approach exists anywhere that iron-rich drainages are being created. The cement industry, in many ways, is an ideal consumer of such sludge and would serve as a large beneficiary of process described. Small levels of impurities that would prevent the use of these materials in other industries are actually beneficial to the cement industry. Many AMDs contain some level of heavy metals. The highly alkaline environment found in hydrated Portland cement results in an environment where these metals are insoluble, thereby providing a safe, stable home for them. Once the use of AMD treatment sludge in the cement industry is demonstrated, other applications are sure to follow thereby increasing the value of the funds requested. The successful completion of the project will not only establish a source of raw materials but also spur interest in other applications. In summary, this project will result in the development of a process with significant economic and environmental benefits. Additionally, the process also will serve as a model for consideration in many other areas of application. The project is the culmination of several years of experience in research related to the utilization of AMD materials.