RT Journal Article
T1 Thermal Transformation of Natural Schwertmannite in the Presence of Chromium
T2 Thermal transformation of Schw
A1 Lázaro, Carlos
A1 Antelo Cortizas, Juan Manuel
A1 Carabante, Iván
A1 Otero-Fariña, Alba
A1 Vázquez Verdes, Pedro
A1 Dacunha-Marinho, Bruno
A1 Fiol López, Sarah
K1 Anoxic conditions
K1 Acid mine drainage
K1 Schwertmannite
K1 Hematite
K1 Termal transformation
K1 Chromium
K1 Arsenic
K1 Adsorption
AB Schwertmannite is a metastable mineral playing a crucial role in the immobilization of metal(oid)s in acid mine drainage (AMD) systems. High temperatures associated with wildfires could lead to a sudden schwertmannite transformation, changing the mobility of metal(oid)s. The objective of the present study was to examine the thermal transformation from schwertmannite to hematite, and the subsequent effect on the chromium partitioning. The immobilization of arsenate after thermal transformation and its implications on chromium mobility was also evaluated. Natural schwertmannite, with increasing contents of chromium, was thermally treated between 200 to 800 °C. Transformation products were characterized by solid-phase techniques and selective chemical extractions. Results indicated a transformation to hematite at temperatures above 400 °C. The presence of chromium barely affected the temperature at which the transformation occurred, although partitioning of chromium in the mineral changed with temperature. As the temperature increased from 25 °C to 400 °C, chromium was less mobile and less outcompeted by arsenic adsorption, suggesting a larger contribution of inner-sphere complexes with increasing temperature. At temperatures above 600 °C, non-mobile forms strongly associated with neo-formed hematite were found. Finally, neo-formation of hematite led to a decrease in arsenic adsorption, implying a potentially enhanced arsenic mobility in AMD systems upon wildfires.
PB MDPI
SN 2075163X
YR 2022
FD 2022-06
LK https://hdl.handle.net/10347/41097
UL https://hdl.handle.net/10347/41097
LA eng
NO Lázaro, C., Antelo, J., Carabante, I., Otero-Fariña, A., Verdes, P. V., Dacunha-Marinho, B., & Fiol, S. (2022). Thermal Transformation of Natural Schwertmannite in the Presence of Chromium. Minerals, 12(6), 726. https://doi.org/10.3390/min12060726
NO Xunta de Galicia - Consellería de Educación e Ordenación Universitaria de Galicia (Consolidation of Competitive Groups of Investigation; GI-1245, ED431C 2018/12)
NO Xunta de Galicia - Consellería de Educación e Ordenación Universitaria de Galicia (CRETUS; ED431E 2018/01)
NO Interreg VA Spain-Portugal Programme (EU) through the project Terramater (0701_TERRAMATER_1_E)
DS Minerva
RD 24 abr 2026