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Show PAPER NO. 11 Performance Testing of Ultrafine Pittsburgh 118 Coal in 12-lnch Advanced Flotation Column W. F. Musio!. J. J. Warchol, S. Y. Shiao. and S. J. Vecci The Babcock & Wilcox Company - Research and Development Divis/on Alliance. Ohio 4460 1 K. E. Harrison and D. D. Ferris ICF Kaiser Engineers Pittsburgh. Pennsy1vania 15222 T. J. Feeley U.S. Department of Energy - Pittsburgh Energy Technology Center Pittsburgh. Pennsylvania 15236 ABSTRACT The criteria for selecting a suitable advanced physical coal cleaning technology are: (1) maximum removal of pyritic sulfur with optimum Btu recovery, (2) high probability of commercial application, and (3) more cost-effective than flue gas desulfurization technology on a $/1On of sulfur removed basis. One physical cleaning technology having the potential to meet these criteria is advanced froth flotation. Babcock & Wilcox (B&W) has participated with ICF Kaiser Engineers to perform a OOE-supported project entitled "Engineering Development of Advanced Physical Fine Coal Cleaning Technologies - Froth Flotation." B&W was responsible for performing process studies in two areas. The rust area was precleaning of the raw Pittsburgh #8 coal in conventional coal preparation equipment (hydrocyclones and rougher flotation cells) to prepare the coal for ultrafine grinding and advanced froth flotation(1). The second area, which is the subject of this paper, was the ultrafme grinding and advanced froth flotation testing. Bench-scale and pilot-scale (100 to 200 poundslhour) tests were conducted at B&W's Alliance Research Center. An 8-liter pilot wet stirred ball mill was used to determine the operating conditions (rpm, media volume, feed solids concentration, and feed rate) and specific energy required to produce the ultrafine coal feed for advanced flotation. Two-inch diameter and 12-inch diameter flotation column cells were used to develop engineering performance and scale-up data for the advanced flotation process. The operating conditions and performance results of the ultrafine grinding and the advanced froth flotation testing are discussed. INTRODUCTION The desulfurization of coal prior to combustion has become an important option in the effective control of acid rain. Babcock & Wilcox has teamed with ICF Kaiser Engineers, Inc.; Virginia Poly technical Institute and State University (VPI); Ohio Coal Development Office (OCDO); Eimco Corporation; Consolidated Coal; The Center for Research on Sulfur in Coal (CRSC); and several developers of advanced flotation technology to perform the engineering development necessary to make advanced flotation technology a viable sulfur control candidate for private sector investment. The primary goal of this project is to develop an advanced froth flotation process which can maximize inorganic sulfur (pyrite) removal from coal while simultaneously reducing ash and achieving extremely high energy recoveries (90% or greater). As a rust phase of this project, a conceptual design for the advanced flotation process was developed and evaluated. Figure 1 shows a simplified process flowsheet identifying the major stages of the advanced flotation process. The process consists of four key unit operations: primary crushing and precleaning, microgrinding, advanced froth flotation, and dewatering. The design philosophy adopted for the advanced flotation process stressed a staged size reduction and precleaning approach commonly used in the mineral processing industry. By controlling the panicle size of the coal in successive physical cleaning operations, the efficiency of each individual operation can be maximized. This is especially important in any advanced physical cleaning process, such as froth flotation, where ultrafme |