The treatment of heavy metal contaminated wash fluids using an electrokinetic depositional plating process

This Doctoral research project was undertaken to develop a new, improved, environmentally sound, and innovative remedial treatment process by which specific heavy metals, lead and cadmium, could be extracted from industrial wastes like electric arc furnace dust.; This research project included the development of a three step process, with the express purpose of attaining the required remedial goals involved and the ultimate removal of specific heavy metals from the industrial waste material, e.g. electric arc furnace dust.; The first step in this process was chelation, which involved the use of a 0.1 molar (M) ethylene-diaminetetraacetic acid (EDTA)/deionized water solution to bond or form an appropriate metal/EDTA complex. Results of this process indicated a cadmium removal efficiency between 70-80% and a lead removal efficiency between 75-80% from the original electric arc furnace dust levels. The liquid wash fluid containing both chelant and metals were then amenable to further treatment.; The second step in this process included the use of a pH adjustment process, which resulted in the lowering of the pH of the wash fluid for the express purpose of breaking those metal/chelate bonds or complexes that existed, and allowed for the direct recovery of the initial EDTA material. As a result of this process between 90-95% of the original EDTA used as a chelant in this process was recovered for use in later material wash processes.; Finally, the third step in this research process was an electrokinetic procedure by which lead and cadmium were liberated by successfully being electro-plated onto the selected graphite cathode electrode. An aqueous removal efficiency of these specific heavy metals was determined to be in the range of 93-97% from the original solution placed in the electro-kinetic unit for remedial treatment.; The technology developed as a result of this Doctoral research is directly applicable to any number of other materials, such as contaminated soils, industrial ash/sludge materials or residues, and solid or slurry materials. The use of this remedial process can show a significant reduction in contaminants.