Thermal Behavior of Pyrite and Its Relation to Carbon and Sulfur Oxidation in Clays

Abstract

The thermal behavior of pyrite in air was studied. A one-step mechanism for the oxidation of pyrite to hematite exists and accounts for previously reported weight-loss, DTA, and gas train data which implied a two-step mechanism. Proper control of the oxidation temperature is very important in completing the pyrite oxidation.

Nanominerals and nanoparticles in feed coal and bottom ash: implications for human health effects

“…Fig. 3a) suggest direct transformation of pyrite upon heating in air, others show transformation into hematite via an intermediate stage involving pyrrhotite growth (Bhargava et al 2009;Bunt and Waanders 2009;Bunt et al 2008;Jorgensen and Moyle 1982;Schorr and Everhart 1969).…”

Phases formed during the thermal analysis of pyrite in air

“…Wustite has not been identified, though its presence was alluded to by Blachere [7] and there were mentions of its formation during the oxidation of pyrrhotite, [13,15]. Sulphate has been claimed to be present, either as the ferrous [2,4,5,[16][17] or ferric forms [2,13], but Schorr and Everhart [6] using high-temperature XRD found no evidence of sulphates. Similarly Niwa and Wada [12], who also used XRD techniques, were unable to find evidence of sulphates.…”

“…Agreement as to the intermediate phases is not unanimous. Pyrrhotite was claimed to be present, or hinted at as a possibility, by many workers (3 -5, 7-9, 11, 12, 14] but it was searched for by Banerjee [2J using XRD and chemical means and Schorr and Everhart [6] using XRD alone, and reported absent. Similarly, although magnetite was claimed to be present by several workers [4,5,8,9,11], Schwab and Philinis [13] could not detect it by XRD.…”

Visible-light-driven inactivation of Escherichia coli K-12 over thermal treated natural pyrrhotite

“…S6A. Therefore, the thermal process can be described by the following reactions based on above results and discussion [18,19,33]:…”

“…For example, NMS need 6 h irradiation to totally inactivate 7 Log 10 cfu/mL E. coli under the optimized condition, accompanied with 0.6 ppm Zn 2+ released into the liquid [5]. Thermal modification of natural minerals may be a good choice to address the above two problems simultaneously, because heating can repair the lattice defects and improve the crystalline degree [13], amplify the crystalline size [14], transform the mineral phase [15][16][17][18], and possibly remove the impurities [19][20][21].…”