Inhibition mechanism of Ca2+, Mg2+ and Fe3+ in fine cassiterite flotation using octanohydroxamic acid.

Liuyi Ren,Ming Zhang,Hang Qiu,Wenqing Qin,Penggang Wei,Yubiao Li

doi:10.1098/rsos.180158

Liuyi Ren, Ming Zhang + Show 4 more

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https://doi.org/10.1098/rsos.180158

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Abstract

The existence of metal ions should not be ignored in both hydrometallurgy and flotation. In this study, the effects of Ca2+, Mg2+ and Fe3+ on the flotation performance of cassiterite using octanohydroxamic acid (OHA) as the collector were investigated by micro-flotation tests, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, contact angle, zeta (ζ) potential measurements and atomic force microscopy (AFM) imaging. The results of the flotation and contact angle experiments showed that the addition of Ca2+, Mg2+ and Fe3+ significantly decreased both the recovery and contact angle of cassiterite with pH ranged from 6.0 to 12.0 in the presence of OHA collector. ζ-Potential measurements, solution chemistry analysis and FTIR measurements indicated that the flotation recovery of the cassiterite declined due to the CaOH+, MgOH+ and Fe(OH)3 sites on the cassiterite surface. XPS results indicated that the chemisorption of OHA and calcium ions on the cassiterite surface finally changed its chemical properties. The AFM images also revealed that new species Fe(OH)3 of Fe3+ formed and adsorbed on the cassiterite surface at pH 9.0. The adsorption of Fe(OH)3 reduced the adsorption of OHA on the cassiterite surface, thus the hydrophobicity of cassiterite was deteriorated.

Highlights

Tin is a common metal used in many areas because of its high malleability, ductility and resistance to corrosion
The binding energies of Sn3d5/2 and Sn3d3/2 on the cassiterite surfaces treated by calcium ions and octanohydroxamic acid (OHA) were decreased by 0.2 eV and 0.1 eV, respectively, compared to the one treated with calcium ions. These results indicate that a weak interaction occurred between the calcium ions and Sn sites on the cassiterite surface, and the Sn sites on the cassiterite surfaces exhibited low reactivity [29,33]
Contact angle results indicated that the contact angle of cassiterite decreased in the presence of both OHA and metal ions compared to OHA alone at the pH range of 6–12

Summary

Introduction

Tin is a common metal used in many areas because of its high malleability, ductility and resistance to corrosion. Cassiterite is an economically important mineral of tin in the Earth’s crust [1]. Gravity separation (including jigs, spirals and tables) is the dominant beneficiation strategy for the recovery of cassiterite based on the density difference between the valuable and associated gangue minerals [2,3,4]. Gravity concentration is sensitive to the particle size. Once cassiterite particle size is below 40 mm, it is greatly lost in the gravity tailings [5]

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