Studies of incipient oxidation of coal-pyrite for improved pyrite rejection. First quarterly technical progress report, October 1, 1992--December 31, 1992
In order to foster the development of advanced coal cleaning technologies fundamental studies.of the initial stages of pyrite oxidation have been.initiated. This work is being done on pyrite surfaces that are freshly fractured in an electrolyte solution. This procedure produces surfaces that are initially unoxidized, allowing the subsequent oxidation processes to be studied in detail. It is shown that freshly fractured pyrite electrodes instantaneously (at fracture) assume a rest potential several hundred millivolts more negative than the usual open-circuit potential. A finite, anodic photocurrent, is also observed on the fractured electrodes. Following cleavage, the rest potential increases, indicating an oxidation reaction occurring on the electrodes. The photocurrent is relatively insensitive to this oxidation process, and to moderate anodic and cathodic polarization. However, strong cathodic polarization to about -0.76 V (SHE) at pH 9.2 causes the photocurrent to decrease to zero. No reversal in the sign of the photocurrent is observed and it is believed that the flat band potential occurs near -0.76 V, i.e., where the photocurrent goes to zero. Voltammetry indicates that pyrite also undergoes cathodic decomposition at -0.76 V. This establishes that pyrite must be cathodically decomposed to reach the flat band potential.
- Research Organization:
- Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Mining and Minerals Engineering
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG22-92PC92547
- OSTI ID:
- 10133384
- Report Number(s):
- DOE/PC/92547-1; ON: DE93009676
- Resource Relation:
- Other Information: PBD: 1992
- Country of Publication:
- United States
- Language:
- English
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