ADVANCED FINE COAL CLEANING USING GRAVITY-BASED SEPARATORS
Dr. Rick Honaker
Dept of Mining Engineering
University of Kentucky
March 23, 2001 3:00pm
Ben Bandy Conference Center
Center for Applied Energy Research
The cleaning of fine coal, which is defined as 1 mm material, has been a major research topic over the past two decades. This emphasis was initially driven by the desire to produce a high-quality fuel by ultrafine grinding and cleaning coal as an alternative to petroleum in the late 1970s. However, the research resulted in the development of technologies that were proven to provide an enhance separation performance for the cleaning of fine coal typically found in operating coal preparation plants. The superior performance realized by the advanced technologies have provided substantial economical benefits by allowing improvements in mass yield from each of the other processing circuits and the overall preparation plant.
Current research continues to enhance the process efficiency of fine coal cleaning with a major emphasis on gravity-based separators. Spiral concentrators have been a popular gravity-based technology since the 1980s when composite materials provided lightweight units that could be installed in multiples to achieve the desired capacity. However, a high separation density and a modest efficiency performance are limiting characteristics of spirals.
Recent studies have found that spiral circuitry arrangements have the ability to decrease the separation density, which has resulted in significant economical gains for a mining company. Teeter-bed separators provide an alternative for cleaning 1 mm x 150 micron coal and have proven to provide separation densities below those achieved from spiral circuits at efficiencies that are comparable to the most efficient coarse coal separators. Furthermore, the development of Enhanced Gravity Separators (EGS) may allow gravity-based separators to be used on for cleaning coal to ultrafine particle size, thereby removing or limiting the need for expensive alternatives. The benefits of efficient fine coal cleaning and the application of advanced gravity-based separators will be discussed in this presentation.