Chemical Coal Cleaning Process and Costs Refinement for Coal-Water Slurry Manufacture. Monthly Report

摘要

Test work in January centered on investigation of HCl leaching parameters. Some initial hot-water leaching tests were also performed. A test series was begun to investigate the effect of HCl leaching conditions on product ash content. Based on the regression analysis of NaOH leaching results, two sets of caustic leach conditions were specified to generate low and higher ash products as feed for leaching. The HCl-leached filter cakes were split in half; one half was analyzed as-is while the other half was subjected to hot-water leaching prior to analysis. Tests conducted on the higher ash products were completed and results are shown in Table 1. In the range of 2 to 10% HCl, an improvement from 1.39 to 1.13% ash after HCl leaching and from 1.10 to 0.93% ash after hot-water leaching was observed. The high ash content shown for Test H2 (0.05% HCl) is a result of the release of additional NaOH after the caustic cake had been initially neutralized. The 0.05% HCl was then not sufficient to generate a low enough pH to remove acid-soluble ash components. Residual chlorine and sulfur levels were monitored. Sulfur levels were essentially the same after acid and hot-water leaching. No difference in sulfur content was observed as a function of acid strength. Residual chlorine levels were reduced after the hot-water leaching step. A trend of higher chlorine content with increasing HCl strength was noted. 2 tables. (ERA citation 10:017878)