TY - GEN
T1 - Synthesis and nature of the reaction of a solid solution of ammonium-potassium arsenojarosite in NaOH medium
AU - Méndez, J. Eliecer
AU - Flores, Mizraim U.
AU - Patiño, Francisco
AU - Reyes, Martín
AU - Juárez, Julio C.
AU - Reyes, Iván A.
AU - Palacios, Elia G.
N1 - Publisher Copyright:
© GDMB. All rights reserved.
PY - 2015
Y1 - 2015
N2 - A solid solution of ammonium-potassium arsenojarosite was synthesized for this study. It was chemically and mineralogically characterized by Inductively Coupled Plasma Spectrometry (ICP), elemental analysis, Atomic Absorption Spectrophotometry (AAS), X-Ray Diffraction (XRD) and Scanning Electron Microscopy with Energy-Dispersive X-Ray Spectroscopy (SEM-EDS). The following composition was obtained: 26.67 % Fe, 36.41 % SO4, 3.60 % K, 1 % NH4, 6.71 % AsO4 and 25.61 % OH–+H2O, which results in the following approximate formula: [(NH4)0.23K0.77] Fe2.47 [(SO4)1.69(AsO4)0.31] [(OH)4.1(H2O)1.9]. The amount of arsenic was higher than the reported by different authors who have synthesized similar compounds. The XRD results confirm that the obtained sample corresponds to ammonium-potassium arsenojarosite. The granulometric analysis showed that the main particle sizes are 38 and 25 µm, corresponding to mesh sizes 400 and 500. This indicates that a fine size particle was obtained. The compound’s nature of thereaction in NaOH was studied as well, showing an induction period characterized by the formation of active sites until a reaction front is established. It is followed by the progressive conversion period, in which K+, SO42- and NH4+increase in the solution until reaching stabilization. The reaction was followed by determination of K with AAS. The obtained results are consistent with the kinetic model of constant-size spherical particles and unreacted core with chemical control. Partially decomposed particles were also observed by SEM, where an unreacted arsenojarosite core, a reaction front and an ash halo made of amorphous Fe(OH)3 with adsorbed AsO4 can be seen.
AB - A solid solution of ammonium-potassium arsenojarosite was synthesized for this study. It was chemically and mineralogically characterized by Inductively Coupled Plasma Spectrometry (ICP), elemental analysis, Atomic Absorption Spectrophotometry (AAS), X-Ray Diffraction (XRD) and Scanning Electron Microscopy with Energy-Dispersive X-Ray Spectroscopy (SEM-EDS). The following composition was obtained: 26.67 % Fe, 36.41 % SO4, 3.60 % K, 1 % NH4, 6.71 % AsO4 and 25.61 % OH–+H2O, which results in the following approximate formula: [(NH4)0.23K0.77] Fe2.47 [(SO4)1.69(AsO4)0.31] [(OH)4.1(H2O)1.9]. The amount of arsenic was higher than the reported by different authors who have synthesized similar compounds. The XRD results confirm that the obtained sample corresponds to ammonium-potassium arsenojarosite. The granulometric analysis showed that the main particle sizes are 38 and 25 µm, corresponding to mesh sizes 400 and 500. This indicates that a fine size particle was obtained. The compound’s nature of thereaction in NaOH was studied as well, showing an induction period characterized by the formation of active sites until a reaction front is established. It is followed by the progressive conversion period, in which K+, SO42- and NH4+increase in the solution until reaching stabilization. The reaction was followed by determination of K with AAS. The obtained results are consistent with the kinetic model of constant-size spherical particles and unreacted core with chemical control. Partially decomposed particles were also observed by SEM, where an unreacted arsenojarosite core, a reaction front and an ash halo made of amorphous Fe(OH)3 with adsorbed AsO4 can be seen.
KW - Arsenojarosite
KW - Characterization
KW - Synthesis
UR - http://www.scopus.com/inward/record.url?scp=84994606519&partnerID=8YFLogxK
M3 - Contribución a la conferencia
AN - SCOPUS:84994606519
T3 - Proceedings - European Metallurgical Conference, EMC 2015
SP - 523
EP - 536
BT - Proceedings - European Metallurgical Conference, EMC 2015
PB - GDMB Verlag GmbH
T2 - 8th European Metallurgical Conference, EMC 2015
Y2 - 14 June 2015 through 17 June 2015
ER -