Semiconductor electrochemistry of coal pyrite

Technical Report · Mon Feb 01 00:00:00 EST 1993

DOI:https://doi.org/10.2172/6939018· OSTI ID:6939018

Osseo-Asare, K; Wei, D

This project seeks to advance the fundamental understanding of the physics-chemical processes occurring at the pyrite/aqueous interface, in the context of coal cleaning, coal desulfurization, and acid minedrainage. A novel approach to the study of pyrite aqueous electrochemistry is proposed, based on the use of both synthetic and natural ( i.e. coal-derived) pyrite specimens, the utilization of.pyrite both in the form of micro (i.e. colloidal and subcolloidal) and macro (i.e. rotating ring disk) electrodes, and the application of in-situ direct electroanalytical and spectroelectrochemical characterization techniques. The kinetic study of the reaction between sulfide and ferrous ions in solution suggested that the black species formed initially is FeHS[sup +] intermediate. To farther confirm this mechanism, the experiments aimed at establishing the stoichiometry for the intermediate were carried out thermodynamically with a stopped-flow spectrophotometric technique. The results showed that the mole ratio of H[sup [minus]]/Fe[sup 2+] is 1 to 1 for the intermediate product, which is in good agreement with the kinetic results previously obtained. Furthermore, the equilibrium constant for the reaction Fe[sup 2+] + H[sup [minus]] = FeHS[sup +] was determined as K = 10[sup 4.34]. The forward rate constant is 10[sup 3.81](mol/l)[sup [minus]1]sec[sup [minus]1] and the backward rate constant is 10[sup [minus]0.53] (mol/l)[sup [minus]1] sec[sup [minus]1].

• Research Organization: Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering
• Sponsoring Organization: USDOE; USDOE, Washington, DC (United States)
• DOE Contract Number: FG22-91PC91303
• OSTI ID: 6939018
• Report Number(s): DOE/PC/91303-T5; ON: DE93012461
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
COAL
DESULFURIZATION
IRON COMPOUNDS
CHEMICAL REACTION KINETICS
PYRITE
ELECTROCHEMISTRY
SULFIDES
CATIONS
CLEANING
EXPERIMENTAL DATA
PROGRESS REPORT
REACTION INTERMEDIATES
SPECTROPHOTOMETRY
CARBONACEOUS MATERIALS
CHALCOGENIDES
CHARGED PARTICLES
CHEMICAL REACTIONS
CHEMISTRY
DATA
DOCUMENT TYPES
ENERGY SOURCES
FOSSIL FUELS
FUELS
INFORMATION
IONS
KINETICS
MATERIALS
MINERALS
NUMERICAL DATA
REACTION KINETICS
SULFIDE MINERALS
SULFUR COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
010300* - Coal
Lignite
& Peat- Preparation- (1987-)
400400 - Electrochemistry
400201 - Chemical & Physicochemical Properties