Effect of liquid to solid ratio on leaching of metals from mineral processing waste

GEOC 110

Souhail R. Al-Abed, National Risk Management Research Laboratory, United States Environmental Protection Agency, 26 W. Martin Luther King Dr, Cincinnati, OH 45268, Jaydeep Purandare, England Geosystem, 15375 Barranca Pkwy, Suite F-106, Irvine, CA 92618, and Derrick Allen, National Risk Management Research Laboratory, USEPA, 26 W. Martin Luther King Dr, Cincinnati, OH 45268.
Various anthropogenic activities generate hazardous solid wastes that are affluent in heavy metals, which can cause significant damage to the environment and human health. A mineral processing waste was used to study the effect of liquid to solid ratio (L/S) on the leaching behavior of metals. Leaching tests in the form of column and batch studies were carried out to investigate liquid to solid ratios ranging from 0.7 to 50. Although the waste passed the limits regulated under the Toxicity Characteristic Leaching Procedure (TCLP), a high concentration of metals was found to leach by the two leaching tests. The leaching of As, Cu and Zn were all highly dependent on the L/S ratio. Higher concentrations of metals were leached at the lower L/S ratios. The leaching of all the three metals was found to stabilize beyond an L/S of about 10. Approximately 70% of the copper measured by acid digestion leached during the batch test. Copper was found at concentrations as high as 300 mg/l at an L/S ratio of about 1.5 as obtained from the column study.
 

Poster Session
6:00 PM-9:00 PM, Tuesday, March 30, 2004 Anaheim Convention Center -- Hall A, Poster

Division of Geochemistry

The 227th ACS National Meeting, Anaheim, CA, March 28-April 1, 2004