Enhancing flotation of smithsonite by using 1,3,5-Triazinane-2,4,6-trithione as sulfidation

1,3,5-Triazinane-2,4,6-trithione (TMT) was used for the first time as a sulfidation agent in the flotation of smithsonite. Results showed that 80.5% recovery rate could be obtained in the presence of TMT $(5 × 10^{-5} mol$ / $L)$ and butyl xanthate $(5 × 10^{-4} mol$ / $L)$. However, the recovery rate was only 59.4% when sodium sulfide $(5 × 10^{-5} mol$ / $L)$ was used. Micro-flotation test and contact angle measurement showed that TMT activation was better than sodium sulfide activation. Besides, the contact angle increased from 32.44° (untreated) to 89.58° (treated with TMT), which was significantly higher than 50.2° (treated with sodium sulfide). Fourier Transform Infrared spectroscopy(FT-IR) and Zeta potential test showed the chemisorption of TMT on the smithsonite surface. The results of ICP spectral detection and solution chemistry calculation revealed that $Zn_3TMT$ complex precipitates in the smithsonite pulp were formed on the mineral surface at pH 6.5. A hydrophobic film was also formed on the mineral surface after TMT treatment, and more adsorption sites were provided for butyl xanthate. Thus, the adsorption of collector was significantly enhanced.