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Title: PDU-scale testing of microbubble flotation

Technical Report ·
OSTI ID:5692185

Work during this past quarter was focused primarily on Task 1.1.4 (Modeling), Task 1.2.4 (Scale-Up Validation) and Task 1.2.5. (Coarse Coal Flotation). A mathematical model was developed to relate air hold-up and bubble diameter within the column to superficial gas and liquid flows. This model was then incorporated into an iterative scale-up procedure which is being validated as part of Task 1.2.4. Scale-up validation tests were conducted using minus 28-mesh run-of-mine Elkhorn seam coal in 6-, 8-, and 14-inch diameter microbubble flotation columns. The model from Task 1.2.4 was used to estimate bubble size data from the experimental data obtained in these tests, and the scale-up procedure was validated for these three columns. Finally, a performance comparison between microbubble column flotation and conventional flotation was carried out using minus 28-mesh Elkhorn seam coal. The microbubble column flotation process was found to reduce the ash content of the final product by approximately 50% over the product produced by conventional flotation at an equivalent combustible recovery. Furthermore, the 14-inch diameter microbubble column was able to produce a product containing approximately 1.5% ash with combustible recoveries in excess of 90% at a throughout of over 300 lb/hr. 4 refs., 10 figs.

Research Organization:
Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (USA). Dept. of Mining and Minerals Engineering
Sponsoring Organization:
USDOE; USDOE, Washington, DC (USA)
DOE Contract Number:
AC22-86PC91274
OSTI ID:
5692185
Report Number(s):
DOE/PC/91274-T5; ON: DE91012251
Country of Publication:
United States
Language:
English