Near Neutral Oxidation Of Pyrite In Coal Slurry Solids Technical Report March 1 May 31 1995

Download or read book Near-neutral Oxidation of Pyrite in Coal Slurry Solids. Technical Report, March 1--May 31, 1995 written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this research project are determining the rate of oxidation of pyrite associated with coaly particles (coal slurry solid) when the pH of the surrounding environment is held at approximately 7.8. Coaly particles that contain pyrite are generated during the preparation of Illinois Basin coal for market. These particles are discharged to an impoundment, which eventually must be reclaimed. The purpose for reclamation is either to prevent the generation of acidic solution as the pyrite in the coal slurry solid reacts with air, or to prevent the migration of the acidic solution to a groundwater aquifer. The reclamation is usually accomplished by covering the impoundment with a four-foot-thick layer of topsoil. One possible alternative method for reclamation of a coal slurry impoundment is to mix in alkaline residue from the fluidized-bed combustion of coal. This codisposal would slow the production of acid and would also neutralize any acid produced. If the codisposal method is found to be environmentally acceptable, it will save the coal mining companies part of their cost of reclamation, and also provide a safe and useful disposal outlet for a portion of the residue that is generated by the fluidized-bed combustion of coal. Pyrite oxidation experiments were conducted during the quarter in the following manner. Air, free of carbon dioxide, is bubbled through water in a covered beaker. The pH is adjusted to 7.8 and the solution is circulated by a peristaltic pump through the coal slurry sample contained in a cellulose thimble in a Soxhlet tube mounted above the beaker. The pH of the solution is continuously statted to 7.8 by addition of NaOH solution. Samples are pipetted from the reaction solution for sulfate determination. The rate of oxidation of pyrite in coal slurry solids sample CSS-2a was calculated from the rate of production of sulfate ion to be 1.71[times] 10[sup[minus]6][micro]mole pyrite per minute per[micro]mole of pyrite present.