Structural collapse in phlogopite mica-rich mine tailings induced by mechanochemical treatment and implications to alkali activation potential. (1st June 2020)

• Record Type: Journal Article
• Authors: Niu, He; Kinnunen, Paivo; Sreenivasan, Harisankar; Adesanya, Elijah; Illikainen, Mirja
• Is Part Of: Minerals engineering. Volume 151(2020)
• Publication Date: 2020-06-01
• Subjects: Mechanochemical treatment -- Vibratory disc mill -- Mine tailings -- Geopolymer precursor -- Amorphization; Mines and mineral resources -- Periodicals; Ressources minérales -- Périodiques; Mines and mineral resources; Periodicals; Electronic journals; 622
• DOI: 10.1016/j.mineng.2020.106331
• Languages: English
• ISSNs: 0892-6875

Abstract

Graphical abstract: Highlights: More than 70% of amorphous content was obtained after 16-min grinding. Thermal properties of all ground samples were detailed. Schematic model of the collapsed phlogopite was proposed. Particles morphology was analysed based on Mineral Liberation Technique. Abstract: The alkali activation of mine tailings is of interest to diminish the impoundment storage of large waste stream from mining industry. However, most of the mine tailings, like phosphate mine tailings generated in Finland, are rather inert and need pre-treatment to induce the reactivity for alkali activation. In this work, mechanochemical treatment was conducted to improve the reactivity of phosphate mine tailings. The ground specimens were subjected to the crystal structural analysis of X-Ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and thermal analyses by Thermogravimetry/Differential Thermal Analysis (TG/DTA), showing the increment of amorphous content and structural degradation as a function of grinding time. The subsequent alkaline reactivity test illustrated incremental alkaline dissolution of Si, Al and K and a schematic diagram of altered phlogopite structure (sources of aluminosilicates in tailings) was also proposed. Additionally, the mineralogical composition of individual particles was carried out by mineral liberation analysis (MLA), thereby evaluating the influence of pre-treatment on the mineralogy of tailings. The results indicate profound micromorphological changes and structural cleavage of the precursor due to grinding, which strongly increase alkaline reactivity.