MRP土壌洗浄プロセスにおける汚染物質の分離

概要

論文の詳細を見る
MRP soil washing is physical-chemical separation based on mining and mineral processing principles for removing a broad range of organic and inorganic contaminants from soil. Generally, contaminants reside and are concentrated in a fine fraction. Grain-size distributions and load curves (contaminant distributions) of feed soil are studied to understand and characterize the soil particle/contaminant relationship. A small amount of contaminated fine particles is separated to the underflow (sand fraction) due to the misplacement of a hydrocyclone. Flotation is very useful for removing contaminated fine particles that remain in the cyclone underflow. In a flotation unit, contaminated particles are selectively made hydrophobic by modifying their surface properties with selective reagents. The hydrophobic particles attach to air bubbles and are carried to a froth layer. The separation of these contaminated particles is achieved by removing the froth layer. The separation of contaminated soil particles is investigated in a large-scale plant to understand the performance and validity of the hydrocyclone and flotation unit. A mathematical model that considers both the contaminant concentration ratio of the froth layer and the amount of froth is introduced and used in evaluating the removal efficiency of flotation.