Examination of the environmental behavior of phosphogypsum with the application of lab-scale experiment.

Abstract

Phosphogypsum (PG) is a reject of the phosphoric acid production process in phosphate fertilizer industries. The process results in the production of relatively large quantities of PG that it might cause serious environmental and human health concerns. The data of a laboratory investigation of PG are presented here. Lab-scale experiments with lysimeters were conducted in order to simulate and examine the environmental characteristics and the temporal behavior of PG leachates in terms of physicochemical characteristics and chemical composition. Based on the results, leachates from already deposited for many years PG or its mixture with marble powder, seemed to have better pH and conductivity values and lower elemental concentrations compared to leachates from freshly disposed PG. However, the leachates characteristics improve and stabilize in both cases after four days of irrigation or of 1080-1240 mm of rain. Most major elements were found to have minimal leachability, and the material satisfied the environmental limits for its disposal at landfills for inert and non-hazardous wastes.