Pyrite and Marcasite Surface Area as Influenced by Morphology and Particle Diameter

Abstract

The morphology of massive and framboidal pyrites and marcasite extracted from lignitic cores was examined with light and scanning electron microscopes. The primary objective was to determine the surface area for these sulfide minerals. Framboidal pyrite spheres consisted of micron‐sized crystals and suggested a high surface area compared to other iron (Fe) sulfides. Specific surface space was determined using the linear form of the B.E.T. equation and N2 gas as the adsorbate.Framboidal pyrite was composed of individual microcrystals that ranged from 1 to 5 µm in diameter. Surface area of framboidal pyrite remained near 2.0 m2/g for mean diameters ranging from 150 to 60 µm but increased to as high as 4.0 m2/g for diameters between 5 and 2 µm. Marcasite spheres were 4 to 5 times larger in diameter than single framboids. Surface area of all fractions of marcasite and massive pyrite ranged from 0.2 to 0.5 m2/g. Specific surface decreased as particle size increased.

Factors Controlling In Situ Biogeochemical Transformation of Trichloroethene: Field Survey

“…In addition, the specific surface area measured by Lee and Batchelor () using the ethylene glycol monoethyl ether method of 27.8 m 2 /g appears to be an order of magnitude too high compared to other measurements. A specific surface area of 2.0 m 2 /g was measured for 60 to 150 µm diameter framboidal pyrite with 1 to 5 µm microcrystals using the Brunauer Emmett Teller method (Pugh et al ). A specific surface area of 0.2 to 3.1 m 2 /g was measured for ground and dry sieved pyrite with a grain size of 63 to 75 µm (Wolfe et al ).…”

Acid demineralization with critical point drying: A method for kerogen isolation that preserves microstructure

“…Although the quantity of kerogen obtained was insufficient to measure the abundance of elements besides C, H, N, O, and S, summing the measured elements plus the abundance of Fe expected by attributing all measured S to pyrite closes material balance to within 7 wt% (which is comprised of undetermined minerals). The surface area of pyrite is approximately 4 m 2 /g [33], which makes a negligible contribution to the surface areas of isolated kerogens listed below. The surface area of the undetermined minerals was assumed to be negligible as well.…”

Implications of Pyrite Oxidation for Engineering Works

“…Framboidal pyrite is widely believed to oxidise faster than pyrite in ''chunks'' or cubes of equal size (e.g., Pugh et al 1981). The porous nature of the structure, a result of the spacing between individual microcrystals, provides a large exposed surface area on which oxidation reactions can occur.…”