A DFT study on the structure–reactivity relationship of aliphatic oxime derivatives as copper chelating agents and malachite flotation collectors

Xianglin Yang,Sheng Liu,Guangyi Liu,Hong Zhong 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.46 No.-

Aliphatic oxime derivatives C7H15CX¼NOH (X = H, CH3, NH2 or OH) have been commercially used ascopper(II) extractants orflotation collectors, but the true nature of their reactivity toward Cu2+ or mineralsurfaces still remains elusive. Using density functional theory (DFT) method, the structure–reactivityrelationship of these aliphatic oxime derivatives was evaluated at B3LYP/6-311 + G(d, p) level. The resultsindicated that the O or N atoms in the head group of octanaldoxime (OTAO), methyl n-heptyl ketoxime(MHKO), N-hydroxyoctanimidamide(HOIM) and n-octanohydroxamic acid (OTHA) are the chemicalreaction center. The reactivity of the aliphatic oxime ionic species increases successively with thereplacement of hydrogen atom by methyl, amino and hydroxyl, suggesting that the affinity of them tocopper species is as follows: OTHA > HOIM > OTAO > MHKO, which coincides with the order of theirbinding energy toward Cu2+. Theflotation performance of aliphatic oxime derivatives to malachite was inthe order of OTHA > OTAO > HOIM > MHKO, which was in line with the combination effect of theirreactivity and hydrophobicity. The established structure–reactivity relationship provides an atomic levelunderstanding of the structural requirements for aliphatic oximes to recover cupric ions or copper oxideminerals.

A novel surfactant, N,N-diethyl-N0-cyclohexylthiourea: Synthesis, flotation and adsorption on chalcopyrite

Zhiling He,Guangyi Liu,Xianglin Yang,Wei Liu 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.37 No.-

In this paper, a novel surfactant, N,N-diethyl-N0-cyclohexylthiourea (DECHTU) was synthesized and firstintroduced as a collector for chalcopyrite flotation. The micro-flotation results demonstratedchalcopyrite with adsorbed DECHTU exhibited good hydrophobicity and was effectively concentratedby nitrogen bubbles under pH 4–8. The adsorption of DECHTU onto chalcopyrite surfaces was fitted wellby the pseudo-second-order model and Langmuir isotherm, and was a spontaneously exothermicchemisorption process. The adsorption enthalpy change, entropy change and free energy change wereDH = 31.10 kJ mol 1, DS = 6.32 J mol 1 and DG (298 K) = 29.41 kJ mol 1, respectively. The activa-tion energy of the adsorption process was 17.39 kJ mol 1. The zeta potential results implied thatDECHTU adsorbed onto chalcopyrite surfaces as its anionic species with the release of H+ ion of NH–C(55S)–N group into aqueous solutions. The XPS spectra confirmed that there existed Cu(I)–DECHTUsurface complexes on chalcopyrite surface by bonding of copper atom with the sulfur atom of DECHTU,accompanying with the reduction of cupric to cuprous.

Cone-beam computed tomography-guided threedimensional evaluation of treatment effectiveness of the Frog appliance

Mujia Li,Xiaoxia Su,Yang Li,Xianglin Li,Xinqin Si 대한치과교정학회 2019 대한치과교정학회지 Vol.49 No.3

Objective: To evaluate the effectiveness of the Frog appliance in three dimensions by using cone-beam computed tomography (CBCT) images. Methods: Forty patients (21 boys and 19 girls), averaged 11.7 years old, with an Angle Class II division 1 malocclusion were included in our study. They had either late mixed dentition or early permanent dentition, and the maxillary second molars had not yet erupted. All patients underwent CBCT before and after the treatment for measuring changes in the maxillary first molars, second premolars, central incisors, and profile. Paired-samples t-test was used to compare the mean difference in each variable before treatment and after the first phase of treatment. Results: The maxillary first molars were effectively distalized by 4.25 mm (p < 0.001) and 3.53 mm (p < 0.05) in the dental crown and root apex, respectively. The tipping increased by 2.25o, but the difference was not significant. Moreover the teeth moved buccally by 0.84 mm (p < 0.05) and 2.87 mm (p < 0.01) in the mesiobuccal and distobuccal cusps, respectively, whereas no significant changes occurred in the root apex. Regarding the anchorage parts, the angle of the maxillary central incisor’s long axis to the sella-nasion plane increased by 2.76o (p < 0.05) and the distance from the upper lip to the esthetic plane decreased by 0.52 mm (p = 0.01). Conclusions: The Frog appliance effectively distalized the maxillary molars with an acceptable degree of tipping, distobuccal rotation, and buccal crown torque, with only slight anchorage loss. Furthermore, CBCT image demonstrated that it is a simple and reliable method for three-dimensional analysis.

The role of HABTC’s hydroxamate and dithiocarbamate groups in chalcopyrite flotation

Sheng Liu,Guangyi Liu,Hong Zhong,Xianglin Yang 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.52 No.-

In this paper, S-[(2-hydroxyamino)-2-oxoethyl]-N,N-dibutyl-dithiocarbamate (HABTC) wasfirst synthesizedand characterized by 1H NMR, 13C NMR and FTIR. The role of HABTC’s hydroxamate anddithiocarbamate groups in chalcopyriteflotation was evaluated by micro-flotation, bench-scaleflotation,adsorption experiments, zeta potential and X-ray photoelectron spectroscopy (XPS). HABTC exhibitedexcellent affinity to chalcopyrite particles under pH 6–10 and achieved superiorflotation recovery ofcopper minerals in comparison with sodium isobutyl xanthate (SIBX). The adsorption thermodynamicsand kinetics elucidated that HABTC adsorption on to chalcopyrite surfaces was a spontaneouslyendothermic chemisorption process. Zeta potential demonstrated that HABTC might chemisorb on to thepositive sites of chalcopyrite surfaces. XPS spectra further revealed that both dithiocarbamate andhydroxamate groups of HABTC anchored on chalcopyrite surfaces through Cu(II)-hydroxamate and Cu(I)-dithiocarbamate configurations, resulting in an enhanced collecting power of HABTC to chalcopyriteparticles.

Thiadiazole-thione surfactants: Preparation, flotation performance and adsorption mechanism to malachite

Yaoguo Huang,Guangyi Liu,Jun Liu,Xianglin Yang,Zhiyong Zhang 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.67 No.-

In this paper, novel thiadiazole-thione surfactants including 5-heptyl-1,3,4-thiadiazole-2-thione (HpSDT), 5-phenyl-1,3,4-thiadiazole-2-thione (PSDT) and 5-(2-hydroxyphenyl)-1,3,4-thiadiazole-2-thione (HPhSDT) were synthesized and originally introduced as collectors in froth flotation. Micro-flotation tests showed that HpSDT exhibited better flotation response to malachite than PSDT and HPhSDT, as well as excellent flotation selectivity against quartz. The contact angle results inferred that the hydrophobization intensity of these collectors toward malachite was in the order as HpSDT > PSDT > HPhSDT. ζ-potential recommended a chemisorption of HpSDT on malachite surfaces. FTIR deduced that cupric or cuprous atoms might bond with the S and N atoms of HpSDT to form a conjugated ring. XPS further gave an additional evidence that HpSDT-Cu(I) complexes were produced on malachite surfaces via combining surface Cu atoms with HpSDT’s N and S atoms, with reducing surface Cu(II) to Cu(I). The tighter orientation arrangement on malachite and stronger hydrophobicity rendered HpSDT to possess better flotation affinity toward malachite than PSDT and HPhSDT.

Separation of chalcopyrite from galena with 3-amyl-4-amino-1, 2, 4-triazole-5-thione collector: Flotation behavior and mechanism

Zhiyong Zhang,Yiming Wang,Guangyi Liu,Sheng Liu,Jun Liu,Xianglin Yang 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.92 No.-

3-Amyl-4-amino-1,2,4-triazole-5-thione (AATT) reacted with Cu2+ or Pb2+ ions in aqueous solutions toform CuAATT and Pb(AATT)2 complexes and their solubility product constants were measured as 10 16.17and 10-20.60, respectively. In the moderately-alkaline media, both chalcopyrite and galena chemisorbedAATT on to their surfaces, and the adsorption amount of AATT on chalcopyrite was bigger than that ongalena, which rendered a stronger hydrophobization toward chalcopyrite. While under the high-alkalinepulp, AATT only chemisorbed on chalcopyrite, not on galena. The micro-flotationfindings indicated thatAATT was a favorable collector forflotation enrichment of chalcopyrite and galena at pH <11.0, andrealized an efficientflotation separation of chalcopyrite from galena under pH>11.5. The CuAATTcomplexwas more insoluble than Pb(AATT)2, which implied a stronger affinity of AATT toward chalcopyrite thangalena and returned their selectiveflotation separation at the high-alkaline condition.