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2 Physicochemical Problems of Mineral Processing

2 2024

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Study on the separation effects of the novel collector ODD on magnesite and quartz

Gao Gui, Sun Haoran, Wang Yulian, Sun Yishen, Han Huili, Yuan Zhigang

Physicochemical Problems of Mineral Processing

2024

Vol. 60, iss. 4

art. no. 190522

Traditional magnesite desilication flotation collectors struggle to efficiently remove quartz from low-grade magnesite, prompting the exploration of new, highly selective flotation collectors. Addressing this need has become a focal point in mineral processing research. This study introduced heptadecylamine ethylimidazoline quaternary ammonium salt (ODD) as a quartz flotation collector for separating quartz from magnesite. Flotation experiments involving single minerals and artificially mixed minerals demonstrated that magnesite and quartz could be effectively separated under specific conditions: an ODD concentration of 40mg/L and pH=7.0. Zeta potential assessments revealed that the adsorption of ODD increased the potential of quartz by 4.4 times compared to magnesite. Furthermore, contact angle measurements illustrated that ODD selectively increased the hydrophobicity of the quartz surface while not affecting the contact angle of magnesite. X-ray photoelectron spectroscopy (XPS) analysis indicated that ODD's selective adsorption at the quartz surface through interaction with the O sites on quartz rather than magnesite. Drawing from these findings, a flotation separation model from magnesite and quartz under the influence of ODD was formulated.

Study on the mechanism of controlling the morphology of basic magnesium carbonate prepared under different hydration conditions

Yang Yang, Bai Limei, Ma Yuxin, Wang Yulian

Physicochemical Problems of Mineral Processing

2024

Vol. 60, iss. 3

art. no. 189757

Basic magnesium carbonate is gaining prominence in flame retardant materials due to its excellent flame-retardant properties and clean decomposition products. This study investigates a hydration-carbonation method to address challenges related to the preparation, morphology control, and stability of magnesium basic carbonate. The impact of hydration conditions on the morphology of the carbonate was analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results indicate that spherical magnesium basic carbonate with regular morphology and uniform particle size can be achieved at a hydration temperature of 50°C for 1.5 hours. However, extending the hydration time and increasing the temperature resulted in irregular morphologies. Molecular dynamics simulations using the CASTEP and Forcite modules of Materials Studio were employed to understand the influence of hydration-carbonation conditions on the carbonate's morphology. The simulations revealed that the (1 1 1) and (2 0 0) crystal faces of MgO, with higher surface energies, promote the formation of precursor magnesium hydroxide nuclei, leading to heterogeneous magnesium alkali carbonate at elevated temperatures. Prolonged hydration time resulted in fragmented carbonate structures. To control the morphology of magnesium alkali carbonate, it is essential to optimize hydration temperature and duration. The simulation results corroborate experimental findings, providing deeper insights into the liquid-gas-solid adsorption relationships during the carbonation process. This study offers valuable guidelines for the controlled synthesis of magnesium basic carbonate, enhancing its applicability in flame retardant materials.