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In this paper, an investigation was conducted on the effects arising from albite, K-feldspar, quartz (three particle sizes) and muscovite (two particle sizes) of spodumene flotation tailings on ceramics, as well as the corresponding crystal changes. As indicated by the results, albite and K-feldspar positively impacted the strength of ceramic materials. The flexural strength of ceramics was increased with the decrease in the particle size of quartz. The flexural strength and linear shrinkage of ceramic materials was increased with decreased particle size of muscovite. The melting of albite and the formation of eutectic phase from albite and quart filled the pores between mineral particles, which were found as the major sintering mechanism of ceramics. Furthermore, during the sintering process, the crystal phase transformation of α-quartz to β-quartz and the de-hydroxylation of muscovite and kaolinite was occurred. Lastly, tailings have the potential to be used as raw materials for ceramic materials. Quartz could be used as ridge materials and green materials for permeable ceramics, albite could be used as flux for low temperature sintered ceramics, and muscovite could be used to prepare mullite refractories. [Display omitted] [ABSTRACT FROM AUTHOR]

This work explored the use of spodumene flotation tailings (SFT) as an aggregate used in cement mortar to mitigate their environmental impact. The principal phase compositions of SFT were quartz (Qtz), feldspar (Fsp) and muscovite (Ms). So, the effects of variations in the particle size of Qtz, and mineral additives, Ms and Fsp, on the compressive strength and hydration products were examined. Ms additives imparted the lowest compressive strength. Finer Qtz aggregates (4000–106 µm) reduced the nano-pore volume, and Ms increased the nano-pore width of cement mortar. In addition, fewer hydration products, and poor crystallinity of both ettringite (Aft) and portlandite resulted in a decrease in the compressive strength of the cement mortar, eventually. Therefore, increasing the particle size or optimisation of the mineral composition of SFT could provide a facile route to improving the mechanical properties of cement mortars. [Display omitted] • SFT results fewer hydration products, and poor crystallisation. • A reduction in the Qtz particle size (4000–106 µm) reduced the compressive strength. • Ms additives imparted the lowest compressive strength because of its properties. • Finer Qtz aggregates (4000–106 µm) resulted in a reduced pore volume. [ABSTRACT FROM AUTHOR]

Spodumene and feldspar have little difference in flotability due to their similar crystal chemistry properties. Fe-octyl hydroxamic acid (OHA) (iron complexes of octyl hydroxamic acid) demonstrates excellent selectivity but restricted collecting performance in spodumene flotation. In this work, we added sodium dodecyl sulfate (SDS) into Fe-OHA to obtain a novel multiple ligand collector, which was named Fe-OHA-SDS to enhance the collection ability of Fe-OHA. The efficient separation of spodumene from feldspar (the recovery difference was about 84 %) was achieved by Fe-OHA-SDS without adding depressants and foaming agents at pH 6.2. The separation mechanisms were explored by Zeta potential, contact angle, in-situ microcalorimetric, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) measurements. The findings revealed that Fe-OHA-SDS was more easily bonded to the spodumene surface than the feldspar surface. Meanwhile, the adsorption of Fe-OHA-SDS significantly expanded the hydrophobicity differences on these two mineral surfaces. The Fe-OHA-SDS was adsorbed on the spodumene surface through the Fe-O bond, which differed from the interaction mechanism of traditional mixed collectors on mineral surfaces. Therefore, Fe-OHA-SDS was an efficient collector with potential application value in spodumene flotation. [Display omitted] [ABSTRACT FROM AUTHOR]

The agglomeration of bastnaesite and fine fluorite severely reduces the recovery of bastnaesite, and a method to address this issue is urgently needed. Using measurement techniques such as micro-flotation, contact angle, zeta potential, in situ attenuated total reflectance-Fourier transform infrared (In situ ATR-FTIR) spectroscopy, and extended theory for calculating the stability of solution colloid (E-DLVO theory), this study investigated the selective adsorption mechanism of sodium hexametaphosphate (SHMP). The flotation results indicated that when sodium oleate (NaOL) was used as the collector, SHMP was 2.5 × 10−6 M, showing an outstanding flotation separation of bastnaesite from fine fluorite. The contact angle and zeta potential results showed that SHMP selectively increased the surface hydrophobicity and decreased the surface potential of fluorite. Additionally, in situ ATR-FTIR spectroscopy measurements revealed that HPO 4 2- and H 2 PO 4 - of SHMP chemically reacted with Ca2+ ions on the surface of fluorite and finally formed CaHPO 4 and Ca(H 2 PO 4) 2 stable complexes. However, SHMP was adsorbed by bastnaesite. Furthermore, EDLVO theoretical calculations confirmed that with the addition of SHMP, the electrostatic attraction of the double electric layer between the particles weakened 10 times, hydration repulsion was intense, and the total force between the particles changed from attractive to repulsive. The results also showed that fluorite and bastnaesite dispersed each other. Thus, SHMP can be used as a high-performance selective depressant for the fluorite flotation to realize bastnaesite flotation. [Display omitted] [ABSTRACT FROM AUTHOR]