Control of pyrite surface chemistry in physical coal cleaning. Eleventh quarterly technical progress report, March 1, 1992--May 31, 1992
With the development of microbubble flotation, flotation also shows considerable promise as a method for cleaning micronized coal to produce superclean and ultraclean fuels. One major goal is to use flotation, as a low-cost physical beneficiation process, to remove pyrite from coal. However, this has proven to be a difficult task because often the pyrite contained in coal can be hydrophobic and reports to the froth. Previous studies have shown that pyrite, like other sulfide minerals, undergoes mixed potential electrochemical reactions when immersed in an aqueous solution. Therefore, it is essential to understand the electrochemical behavior of pyrite in order to effectively reject pyrite from coal. In a previous report, it was shown that pyrite could be successfully rejected from several coal samples by manipulating the solution potential with reducing and oxidizing reagents. Controlling the redox potential of flotation circuits offers a novel and very promising route for coal desulfurization by depressing the pyrite during flotation without adversely affecting the natural hydrophobicity of coal. However, much more work is needed to understand the mechanisms responsible for the natural flotation and electrochemical depression of pyrite to improve the effectiveness of this technique. During this report period, new work on using a particulate bed electrolyte composed of pyrite particles was initiated so the flotation of pyrite could be determined as a function of potential without using chemical redox reagents. This technique will simultaneously provide information on the electrochemical reactions taking place on the particulate bed electrodes, the flotation response, and any dissolved species in solution that have chromophores in the ultraviolet-visible region of the spectrum.
- Research Organization:
- Virginia Center for Coal and Minerals Processing, Blacksburg, VA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG22-89PC89789
- OSTI ID:
- 10178578
- Report Number(s):
- DOE/PC/89789-T11; ON: DE92040448
- Resource Relation:
- Other Information: PBD: [1992]
- Country of Publication:
- United States
- Language:
- English
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