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Study on fluoride fixation effect of Bayan Obo rare earth iron ore and three sodium agents under microwave irradiation

Guo Jing, Wen Ming, Li Jie, Hong Xunhai, Zhang Wenhao, Wang Yonglun

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 1

63--76

EN

To investigate the fluorine fixation of Bayan Obo rare-earth iron ores in beneficiation and metallurgy processes, the effect of three sodium agents, namely, sodium hydroxide, sodium carbonate, and sodium bicarbonate, on fluorine fixation under the action of microwaves was investigated using Xray diffraction, chemical detection, and orthogonal experiments. The effects of different types of sodium, roasting temperatures, sodium ratios, and roasting times on the fluorine fixation rate were evaluated. Results show that compared with conventional roasting, the fluorine fixation efficiency of Bayan Obo rare-earth iron ore under the action of microwave is superior after the formulation of the sodium agent, which is crucial for the study. Among the three sodium agents, the fluorine fixation effect of NaHCO3 can be used as the preferred sodium agent. Orthogonal experiments showed that the factors influencing the magnitude of the fluorine fixation rate are the roasting temperature, sodium agent ratio, and roasting constant temperature time in the order of priority. The optimal conditions for the fluorine fixation process are the microwave roasting temperature of 973.15 K, sodium bicarbonate ratio of 40%, and roasting time of 60 min. The highest fluorine fixation rate of 86.72% can be obtained. The findings of this study can provide a reference for the development of green and economic recovery processes for Bayan Obo rare-earth iron ores.

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Mechanistic study on the flotation of barite with C18H33NaO2 under microwave radiation based on UV-visible spectrophotometric analysis

Guo Jing, Wen Ming, Wu Jingxuan

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 6

art. no. 156349

EN

Based on the pure mineral flotation tests of barite, this study investigated the effect law of microwave on barite flotation by using a UV-visible spectrophotometer (L5), solution chemistry calculation, and zeta potential, scanning electron microscope (SEM), and other testing methods. Additionally, red flotation kinetic analysis was carried out to deeply explore the mechanism of C18H33NaO2 flotation of barite under microwave radiation. Mineral flotation tests showed that after microwave treatment, the flotation recovery of barite and deionized water increased by 2.67% and 3.35%, respectively, while that of the microwave action pulp and chemically added pulp decreased by 2.90% and 8.51%, respectively. Microwave action on barite can improve its flotation recovery (up to 95.27%). The action of microwave heating can improve the positive electrical properties of the surface of barite, and accordingly, its specific surface area would be enlarged. In this case, the adsorption rate of sodium oleate on the surface of barite increased, thereby improving the flotation recovery. The flotation kinetics analysis revealed that the k-value of the primary kinetic model was the most informative among the four models of flotation kinetics, and its fitting results can truly reflect the flotation results of barite before and after the microwave action. Through the analysis of barite flotation adsorption experiment under microwave action and with sodium oleate as a collector, this study revealed the mechanism of C1818H33NaO2 on barite flotation under a microwave roaster. This study provides an important reference for the research on efficient barite flotation.

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Internal Friction Study on the Influence of Pre-Deformation on Hydrogen Embrittlement Sensitivity of Dual-Phase Steel

Pang Qihang, Geng Cong, Wang Jiaji, Li Weijuan, Guo Jing, Yu Xiaoming

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 4

1315--1324

EN

In this study, an electrochemical method was used to permeate hydrogen through annealed DP590 steel under various pre-strain conditions (0-15%). Stress-strain and internal friction-temperature curves of the dual phase (DP) steel were obtained from slow strain-rate tensile tests and internal friction measurements, respectively. The diffusion of interstitial atoms, formation of Cottrell atmospheres, and embrittlement mechanism of DP steel were investigated under different prestress conditions before and after hydrogen permeation. The results show that the tensile strength of DP steel first decreases and then increases and the elongation sharply decreases with increasing pre-strain. The strength and ductility present similar trends with changes in pre-strain before and after hydrogen charging, however, after hydrogen charging, an obvious increase in tensile strength and decrease in elongation are observed. Furthermore, the γ peak amplitude decreases and the Snoek-Ke-Koster (SKK) peak amplitude increases with increasing internal pre-strain according to the friction-temperature curve. The γ peak and SKK peak exhibit the same trends with increasing pre-strain before and after hydrogen charging and both the γ peak and SKK peak decrease with hydrogen charging. The dislocation density in DP steel increases after hydrogen charging.

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Citric acid inhibits the floatability of quartz in the Mg2+ system

Wang Yonglun, Li Jie, Zhang Wenhao, Li Pengwei, Guo Jing, Yao Kai

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 6

1--11

EN

Citric acid is a small-molecule organic acid, which can be used as an inhibitor for the flotation of Mg2+ activated quartz. Methods such as flotation experiments, zeta potential, FTIR qualitative and quantitative calculations, and solution chemistry calculations were used in this study to conduct systematic research to study activation and inhibition mechanisms. The results show that adding only a quarter of citric acid under the optimal conditions of Mg2+ activated quartz produces the best inhibitory effect. Mg2+ and citric acid affect the zeta potential of the quartz surface in the zeta potential experiment. FTIR qualitatively found that under the action of Mg2+, sodium oleate was adsorbed on the quartz surface in the form of physical adsorption; quantitative analysis clearly explained that after the chemical reaction between citric acid and Mg2+, it desorbed from the quartz surface into the water system. According to the chemical calculation of the solution during the flotation process, it is found that the reaction product of citric acid and Mg2+ has no inhibitory effect; only the amount of Mg2+ is consumed, thereby reducing the number of activating factors and cutting off the medium of sodium oleate adsorbed on the surface of the quartz.