Skip to main content Accessibility help
×
Home

Thermal desulfurization of pyrite: An in situ high-T neutron diffraction and DTA–TGA study

  • Hongwu Xu (a1), Xiaofeng Guo (a1), Lani A. Seaman (a2), Aaron J. Harrison (a2), Stephen J. Obrey (a2) and Katharine Page (a3)...

Abstract

To study thermal desulfurization of pyrite (FeS2), we conducted in situ neutron diffraction experiments in the temperature range 298–1073 K. On heating, pyrite remained stable up to 773 K, at which it started to decompose into pyrrhotite (Fe1−xS) and S2 gas. Rietveld analysis of the neutron data from 298 to 773 K allowed determination of the thermal expansion coefficient of pyrite (space group Pa $\bar 3$ ) to be αV = 3.7456 × 10−5 K−1, which largely results from the expansion of the Fe–S bond. With further increase in temperature to 1073 K, all the pyrite transformed to pyrrhotite (Fe1−xS) at 873 K. Unit-cell parameters of Fe1−xS (space group P63/mmc) increase on heating and decrease on cooling. However, the rates in cell expansion are larger than those in contraction. This hysteresis behavior can be attributed to continuous desulfurization of pyrrhotite (i.e., x in Fe1−xS decreases) with increasing temperature until the stoichiometric troilite (FeS) was formed at 1073 K. On cooling, troilite underwent a magnetic transition to an orthorhombic structure (space group Pnma) between 473 and 573 K. In addition, using differential thermal analysis (DTA) and thermogravimetric analysis (TGA) implemented with a differential scanning calorimeter, we performed kinetic measurements of pyrite decomposition. Detailed peak profile and Arrhenius (k = A exp(−Ea/RT)) analyses yielded an activation energy Ea of 302.3 ± 28.6 kJ/mol (based on DTA data) or 302.5 ± 26.4 kJ/mol (based on TGA data) and a ln(A) of 35.3 ± 0.1.

Copyright

Corresponding author

a)Address all correspondence to this author. e-mail: hxu@lanl.gov

Footnotes

Hide All
b)

Present address: Department of Chemistry, Washington State University, Pullman, Washington 99164, USA.

Footnotes

References

Hide All
1.Vaughan, D.J.: Sulfide mineralogy and geochemistry. (Rev. Mineral. Geochem. Volume 61, Mineralogical Society of America, Chantilly, VA, 2006) 714 pp.
2.Lin, Z. and Quvarfort, U.: Predicting the mobility of Zn, Fe, Cu, Pb, Cd from roasted sulfide (pyrite) residues—A case study of wastes from the sulfuric acid industry in Sweden. Waste Manage. 16, 671 (1996).
3.Hiskey, J. and Pritzker, M.: Electrochemical behavior of pyrite in sulfuric acid solutions containing silver ions. J. Appl. Electrochem. 18, 484 (1988).
4.Barnard, A.S. and Russo, S.P.: Shape and thermodynamic stability of pyrite FeS2 nanocrystals and nanorods. J. Phys. Chem. C 111, 11742 (2007).
5.Hu, G., Dam-Johansen, K., Wedel, S., and Hansen, J.P.: Decomposition and oxidation of pyrite. Prog. Energy Combust. Sci. 32, 295 (2006).
6.Deng, J., Wen, S., Chen, X., Xian, Y., and Wu, D.: Dynamic simulation of the thermal decomposition of pyrite under vacuum. Metall. Mater. Trans. A 45, 2445 (2014).
7.Hurst, H.J., Levy, J.H., and Warne, S.S.J.: The application of variable atmosphere thermomagnetometry to the thermal decomposition of pyrite. React. Solids 8, 159 (1990).
8.Lambert, J.M., Simkovich, G., and Walker, P.L.: The kinetics and mechanism of the pyrite-to-pyrrhotite transformation. Metall. Mater. Trans. B 29, 385 (1998).
9.Bhargava, S.K., Garg, A., and Subasinghe, N.D.: In situ high-temperature phase transformation studies on pyrite. Fuel 88, 988 (2009).
10.Xu, H., Zhao, Y., Vogel, S.C., Daemen, L.L., and Hickmott, D.D.: Anisotropic thermal expansion and hydrogen bonding behavior of portlandite: A high-temperature neutron diffraction study. J. Solid State Chem. 180, 1519 (2007).
11.Xu, H., Zhao, Y., Zhang, J., Hickmott, D.D., and Daemen, L.L.: In situ neutron diffraction study of deuterated portlandite Ca(OD)2 at high pressure and temperature. Phys. Chem. Miner. 34, 223 (2007).
12.Xu, H.W., Zhao, Y.S., Vogel, S.C., Hickmott, D.D., Daemen, L.L., and Hartl, M.A.: Thermal expansion and decomposition of jarosite: A high-temperature neutron diffraction study. Phys. Chem. Miner. 37, 73 (2010).
13.Xu, H.W., Costa, G.C.C., Stanek, C.R., and Navrotsky, A.: Structural behavior of Ba1.24Al2.48Ti5.52O16 hollandite at high temperature: An in situ neutron diffraction study. J. Am. Ceram. Soc. 98, 255 (2015).
14.Xu, H.W., Zhao, Y.S., Hickmott, D.D., Lane, N.J., Vogel, S.C., Zhang, J.Z., and Daemen, L.L.: High-temperature neutron diffraction study of deuterated brucite. Phys. Chem. Miner. 40, 799 (2013).
15.Hong, Y. and Fegley, B. Jr.: The kinetics and mechanism of pyrite thermal decomposition. Ber. Bunsenges. Phys. Chem. 101, 1870 (1997).
16.Andresen, A.F.: Magnetic phase transitions in stoichiometric FeS studied by means of neutron diffraction. Acta Chem. Scand. 14, 919 (1960).
17.Wang, H. and Salveson, I.: A review on the mineral chemistry of the non-stoichiometric iron sulphide, Fe1−xS (0 ≤ x ≤ 0.125): Polymorphs, phase relations and transitions, electronic and magnetic structures. Phase Transitions 78, 547 (2005).
18.Marshall, W.G., Nelmes, R.J., Loveday, J.S., Klotz, S., Besson, J.M., Hamel, G., and Parise, J.B.: High-pressure neutron-diffraction study of FeS. Phys. Rev. B 61, 11201 (2000).
19.Baranov, N.V., Ibrahim, P.N.G., Selezneva, N.V., Kazantsev, V.A., Volegov, A.S., and Shishkin, D.A.: Crystal structure, phase transitions and magnetic properties of pyrrhotite-type compounds Fe7−xTixS8. Phys. B 449, 229 (2014).
20.Li, F. and Franzen, H.F.: From pyrrhotite to troilite—An application of the Landau theory of phase-transitions. J. Alloys Compd. 215, L3 (1994).
21.Powell, A.V., Vaqueiro, P., Knight, K.S., Chapon, L.C., and Sanchez, R.D.: Structure and magnetism in synthetic pyrrhotite Fe7S8: A powder neutron-diffraction study. Phys. Rev. B 70, 014415, 1 (2004).
22.Tenailleau, C., Etschmann, B., Wang, H., Pring, A., Grguric, B.A., and Studer, A.: Thermal expansion of troilite and pyrrhotite determined by in situ cooling (873 to 373 K) neutron powder diffraction measurements. Mineral. Mag. 69, 205 (2005).
23.de Villiers, J.P.R. and Liles, D.C.: The crystal-structure and vacancy distribution in 6C pyrrhotite. Am. Mineral. 95, 148 (2010).
24.King, H.E. Jr. and Prewitt, C.T.: High-pressure and high-temperature polymorphism of iron sulfide (FeS). Acta Crystallogr., Sect. B: Struct. Crystallogr. Cryst. Chem. 38, 1877 (1982).
25.Andresen, A.F. and Torbo, P.: Phase transitions in FexS (x = 0.90–1.00) studied by neutron diffraction. Acta Chem. Scand. 21, 2841 (1967).
26.Rietveld, H.: A profile refinement method for nuclear and magnetic structures. J. Appl. Crystallogr. 2, 65 (1969).
27.Chrysta, S.B.: Thermal expansion of iron pyrites. Trans. Faraday Soc. 61, 1811 (1965).
28.Selivanov, E.N., Vershinin, A.D., and Gulyaeva, R.I.: Thermal expansion of troilite and pyrrhotine in helium and air. Inorg. Mater. 39, 1097 (2003).
29.Wendlandt, W.W.: Reaction kinetics by differential thermal analysis: A physical chemistry experiment. J. Chem. Educ. 38, 571 (1961).
30.Kissinger, H.E.: Reaction kinetics in differential thermal analysis. Anal. Chem. 29, 1702 (1957).
31.Coats, A.W. and Bright, N.F.H.: The kinetics of the thermal decomposition of pyrite. Can. J. Chem. 44, 1191 (1966).
32.Charpentier, L. and Masset, P.J.: Thermal decomposition of pyrite FeS2 under reducing conditions. Mater. Sci. Forum 654–656, 2398 (2010).
33.Li, R., Zhang, J., Tan, R., Gerdes, F., Luo, Z., Xu, H., Hollingsworth, J.A., Klinke, C., Chen, O., and Wang, Z.: Competing interactions between various entropic forces toward assembly of Pt3Ni octahedra into a body-centered cubic superlattice. Nano Lett. 16, 2792 (2016).
34.Phillips, B.L., Xu, H., Heaney, P.J., and Navrotsky, A.: 29Si and 27Al MAS-NMR spectroscopy of β-eucryptite (LiAlSiO4): The enthalpy of Si,Al ordering. Am. Mineral. 85, 181 (2000).
35.Zhu, J., Du, S., Yu, X., Zhang, J., Xu, H., Vogel, S.C., Germann, T.C., Francisco, J.S., Izumi, F., Momma, K., Kawamura, Y., Jin, C., and Zhao, Y.: Encapsulation kinetics and dynamics of carbon monoxide in clathrate hydrate. Nat. Commun. 5, 4128 (2014).
36.Zhang, J., Celestian, A., Parise, J.B., Xu, H., and Heaney, P.J.: A new polymorph of eucryptite (LiAlSiO4), ε-eucryptite, and thermal expansion of α- and ε-eucryptite at high pressure. Am. Mineral. 87, 566 (2002).
37.Xu, H., Navrotsky, A., Nyman, M.D., and Nenoff, T.M.: Thermochemistry of microporous silicotitanate phases in the Na2O–Cs2O–SiO2–TiO2–H2O system. J. Mater. Res. 15, 815 (2000).
38.Neuefeind, J., Feygenson, M., Carruth, J., Hoffmann, R., and Chipley, K.K.: The Nanoscale ordered MAterials diffractometer NOMAD at the spallation neutron source SNS. Nucl. Instrum. Methods Phys. Res., Sect. B 287, 68 (2012).
39.Larson, A.C. and Von Dreele, R.B.: General structure analysis system (GSAS); Los Alamos National Laboratory Report LAUR. 86–748, Los Alamos, NM, 2004, 224 pp.
40.Bayliss, P.: Crystal structure refinement of a weakly anisotropic pyrite. Am. Mineral. 62, 1168 (1977).
41.Alsén, N.: Röntgenographische Untersuchung der Kristallstrukturen von Magnetkies, Breithauptit, Pentlandit, Millerit und verwandten Verbindungen. Geol. Fören. Förh. 47, 19 (1925).
42.Von Dreele, R.B., Jorgensen, J.D., and Windsor, C.G.: Rietveld refinement with spallation neutron powder diffraction data. J. Appl. Crystallogr. 15, 581 (1982).
43.Guo, X., Ushakov, S.V., Labs, S., Curtius, H., Bosbach, D., and Navrotsky, A.: Energetics of metastudtite and implications for nuclear waste alteration. Proc. Natl. Acad. Sci. U. S. A. 111, 17737 (2014).
44.Guo, X., Wu, D., Xu, H., Burns, P.C., and Navrotsky, A.: Thermodynamic studies of studtite thermal decomposition pathways via amorphous intermediates UO3, U2O7, and UO4. J. Nucl. Mater. 478, 158 (2016).
45.Guo, X. and Xu, H.: Enthalpies of formation of polyhalite: A mineral relevant to salt repository. J. Chem. Thermodyn. 114, 44 (2017).

Keywords

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed