The development of a construction material using electric arc furnace dust

Abstract

During the 1970s, the United States passed a series of laws regulating the handling and disposal of hazardous material. The new rules drastically increased the cost of processing toxic wastes. Consequently, many producers began investigating methods that would render toxic material non-hazardous. one solution developed was cement encapsulation, a process that incorporates toxic material into a cement matrix, thus solidifying the waste and reducing the potential for the migration of toxins into the environment. This process can be used to prepare a waste for disposal or can be used to develop a construction material, thus mitigating costs further. This solution was selected by Roanoke Electric Steel as a possible way to dispose of electric arc furnace dust, a by-product which contains a variety of heavy metals which are classified as hazardous by the United States Environmental Protection Agency.

In this study, the furnace dust was incorporated into mortar as a portion of the fine aggregate. By including a chelating agent and a stabilizing agent, mortar was developed which meets the requirements of ASTM C150 with respect to strength and time of setting. The optimum mixture has a 28 day strength of 4500 psi and passed the EP Toxicity test, as required by the Environmental Protection Agency before a material can be delisted. To further validate the use of furnace dust in masonry products, the mortar was evaluated for its dimensional stability, both physical and chemical, and for its freezing and thawing durability characteristics.