Surface Analysis of Cassiterite with Sodium Oleate in Aqueous Solution

Effect of Al (III) Ions on the Separation of Cassiterite and Clinochlore Through Reverse Flotation

Most hydrophobic clay minerals, such as clinochlore, are known to cause problems in the recovery of cassiterite. In this study, a new reagent scheme, i.e., sodium oleate (NaOL) as a collector and Al (III) ions as a depressant, for reverse flotation separation of cassiterite and clinochlore was investigated. The flotation performance and interaction mechanism were studied by microflotation tests, adsorption tests, contact angle measurements, and X-ray photoelectron spectroscopy (XPS) analysis. Results of single mineral flotation experiments showed that NaOL had a different flotation performance on cassiterite and clinochlore, and the addition of Al (III) ions could selectively inhibit the floatability of cassiterite. Reverse flotation tests performed on mixed minerals indicated that the separation of cassiterite and clinochlore could be achieved in the presence of NaOL and Al (III) ions. Adsorption experiments demonstrated that Al (III) ions hindered the adsorption of NaOL on cassiterite surfaces but exerted little influence on the adsorption of NaOL on clinochlore surfaces. Results of contact angle measurements indicated that Al (III) ions could impede the hydrophobization process of cassiterite in NaOL solution. XPS results showed that aluminum species were adsorbed onto the cassiterite surfaces through the interaction with O sites.

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

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.