TY - JOUR
T1 - Incorporating pH into DFT-D+U and microflotation recovery studies on heterocyclic collector-pyrite interactions
AU - Mkhonto, Peace P.
AU - Zhang, Xingrong
AU - McFadzean, Belinda
AU - Taguta, Jestos
AU - Zhu, Yangge
AU - Han, Long
AU - Ngoepe, Phuti E.
N1 - Publisher Copyright:
© 2024 The Author(s)
PY - 2024/6/13
Y1 - 2024/6/13
N2 - This study adopted both computational and experimental approaches to design by modification of 2-mercaptobenzothiazole (MBT), 2-mercaptobenzoxazole (MBO) and 2-mercaptobenzimidazole (MBI) heterocyclic collectors by introducing a carbon sulphide (–CS2) group and forming 2-trithiocarbonatebenzothiazole (TTCBT), 2-trithiocarbonatebenzoxazole (TTCBO) and 2-trithiocarbonatebenzomidazole (TTCBI) derivatives collectors. The adsorption behaviour of the heterocyclic collectors (and derivatives) on pyrite and subsequent hydrophobicity at different pH conditions were characterised using molecular modelling and microflotation approaches, respectively. The computational adsorptions were performed on dry and hydrated surfaces in their neutral thiolate and thione (acidic) form on the pyrite (1 0 0) surface. It was found that under dry and neutral conditions the TTCBONa and TTCBTNa were more exothermic, while under dry and acidic conditions the TTCBIH was more exothermic followed by MBIH and MBTH. Under hydrated and neutral conditions MBONa was predicted as the most exothermic, while for hydrated and acidic conditions MBTH, TTCBTH and TTCBIH were more exothermic. It was found that under acidic conditions, the heterocyclic collectors were more exothermic than for neutral condition on the hydrated surface. The microflotation at pH = 8 showed that MBO achieved higher recoveries, while at pH = 6 MBT, TTCBT and TTCBI achieved higher recoveries that could reach 90 %. The derivatives under acidic conditions were found to have good recovery performance, which showed that the introduction of a –CS2 group on the exocyclic sulphur atom improved the affinity and therefore hydrophobicity of the mercapto-heterocyclic collectors on the pyrite surface, and thus these derivatives can enhance the flotation of pyrite minerals. In addition, the computational predictions complimented by experimental recoveries are essential to a meaningful development of modelling as a tool in mineral processing reagent design.
AB - This study adopted both computational and experimental approaches to design by modification of 2-mercaptobenzothiazole (MBT), 2-mercaptobenzoxazole (MBO) and 2-mercaptobenzimidazole (MBI) heterocyclic collectors by introducing a carbon sulphide (–CS2) group and forming 2-trithiocarbonatebenzothiazole (TTCBT), 2-trithiocarbonatebenzoxazole (TTCBO) and 2-trithiocarbonatebenzomidazole (TTCBI) derivatives collectors. The adsorption behaviour of the heterocyclic collectors (and derivatives) on pyrite and subsequent hydrophobicity at different pH conditions were characterised using molecular modelling and microflotation approaches, respectively. The computational adsorptions were performed on dry and hydrated surfaces in their neutral thiolate and thione (acidic) form on the pyrite (1 0 0) surface. It was found that under dry and neutral conditions the TTCBONa and TTCBTNa were more exothermic, while under dry and acidic conditions the TTCBIH was more exothermic followed by MBIH and MBTH. Under hydrated and neutral conditions MBONa was predicted as the most exothermic, while for hydrated and acidic conditions MBTH, TTCBTH and TTCBIH were more exothermic. It was found that under acidic conditions, the heterocyclic collectors were more exothermic than for neutral condition on the hydrated surface. The microflotation at pH = 8 showed that MBO achieved higher recoveries, while at pH = 6 MBT, TTCBT and TTCBI achieved higher recoveries that could reach 90 %. The derivatives under acidic conditions were found to have good recovery performance, which showed that the introduction of a –CS2 group on the exocyclic sulphur atom improved the affinity and therefore hydrophobicity of the mercapto-heterocyclic collectors on the pyrite surface, and thus these derivatives can enhance the flotation of pyrite minerals. In addition, the computational predictions complimented by experimental recoveries are essential to a meaningful development of modelling as a tool in mineral processing reagent design.
KW - Adsorption of energies
KW - DFT-D+U
KW - Heterocyclic collectors
KW - Microflotation
KW - Pyrite mineral
KW - pH conditions
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UR - http://www.scopus.com/inward/citedby.url?scp=85185188207&partnerID=8YFLogxK
U2 - 10.1016/j.seppur.2024.126430
DO - 10.1016/j.seppur.2024.126430
M3 - Article
AN - SCOPUS:85185188207
SN - 1383-5866
VL - 337
JO - Separation and Purification Technology
JF - Separation and Purification Technology
M1 - 126430
ER -