Molten-Caustic-Leaching (Gravimelt) System Integration Project. Quarterly report, July--September 1989

Operation of the Gravimelt Integrated Test Circuit for desulfurization and demineralization of coal has been completed. A 48-test process matrix was performed over 750 hours of operational time resulting in production of 3,000 pounds of treated coal suitable for further test and evaluation. Analysis of the several thousand data is underway. Assessment of coal material balance data shows an average 98% closure with 2% conversion of coal to humics and phenolics, 3% conversion to hydrogen and methane and 3 1/2% loss as carbonate. Assessment of sulfur forms data shows a mean residual pyritic sulfur of 0.022% for Pittsburgh No. 8 seam coal and 0.01% for Kentucky No. 9. Organic sulfur removal was dependent on conditions with lowest at 0.08% after processing in the plant. The mean sulfate sulfur level was 0.28% with a standard deviation of only 0.06%