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2 Physicochemical Problems of Mineral Processing

2 2020

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Study of N, N-bis (2-hydroxyethyl) -N-methyl dodecyl ammonium chloride as the novel collector in selective flotation separation of quartz and hematite

Liu Wenbao, Liu Wengang, Zhao Qiang, Wang Xinyang, Duan Hao, Peng Xiangyu, Wang Benying

Physicochemical Problems of Mineral Processing

2020

Vol. 56, iss. 2

286--299

A quaternary ammonium salt, N, N-bis (2-hydroxyethyl)-N-methyl dodecyl ammonium chloride (BHMDC), with high surface activity, was screened and firstly introduced in the reverse flotation of hematite ores based on Density Functional Theory (DFT) calculation and surface tension measurement. The interaction mechanism of BHMDC on the surfaces of quartz and hematite was studied by zeta potential measurement, X-ray photoelectron spectroscopy (XPS) and Fourier transforms infrared spectroscopy (FTIR), respectively. The results of DFT calculation and surface tension measurement indicated that BHMDC had higher selectivity and hydrophobicity than dodecylamine (DDA). The analyses of zeta potential measurement, FTIR, and XPS demonstrated that the adsorption of BHMDC on hematite and quartz surfaces were mainly dependent on hydrogen bonding and electrostatic interaction. Due to the more active sites (O atoms), the weaker charge and larger size of polar groups, BHMDC had better simulation results in performance than DDA, especially in selectivity. The flotation tests showed that BHMDC exhibited better flotation performance, which was consistent with the results of DFT calculation. And the efficient separation of hematite and quartz within the wide pH value range (4.0-10.0) was determined, which was also confirmed by zeta potential measurement. It also indicated that BHMDC was an excellent collector in the reverse flotation of hematite ores with great industrial potential, which could obtain the concentrate with the Fe grade of 65.37% and recovery of 88.92%

Investigating flotation behavior and mechanism of modified mineral oil in the separation of apatite ore

Wei Kefeng, Liu Wenbao, Peng Xiangyu, Liu Wengang, Naixu Zhang, Li Zhen

Physicochemical Problems of Mineral Processing

2020

Vol. 56, iss. 3

471--482

In order to enhance the separation floatation of apatite ore, one mineral oil (MO), a petroleum base oil, as a raw material was modified to obtain a novel high-efficiency collector. The optimized modified mineral oil collector (MPBO) was obtained by systematically modified experiments. The results showed that the optimized condition of modification was air-flow rate 0.15 m3/h, potassium permanganate 0.2% (0.04 g), the reaction time 24 h and the temperature 140 °C. The flotation performance and mechanism of MPBO were further studied by flotation tests, zeta potential measurements, Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The results of flotation tests showed that MPBO had a higher selectivity than oxidized paraffin soap. When 400 g/t MPBO was used as collector, the concentrate with 96.89% P2O5 recovery and 26.08% P2O5 grade was obtained. It also indicated that MPBO as the collector not only significantly improved the separation index of apatite ore flotation, but also greatly shortened and simplified the flotation process. The analysis of zeta potential, FTIR spectra and XPS revealed that carboxyl group was presented in the MPBO, which could form calcium carboxylate with calcium ion on the apatite surface by chemisorption.