Shu Kaiqian, Xu Longhua, Wu Houqin, Wang Zhoujie, Xu Yanbo, Fang Shuai
Key Laboratory of Solid Waste Treatment and Resource Recycle Ministry of Education, Southwest University of Science and Technology, Mianyang, Sichuan, PR China.
Key Laboratory of Solid Waste Treatment and Resource Recycle Ministry of Education, Southwest University of Science and Technology, Mianyang, Sichuan, PR China; State Key Laboratory for Environment-friendly Energy Materials, Southwest University of Science and Technology, Mianyang, Sichuan, PR China.
Ultrason Sonochem. 2019 Oct;57:98-107. doi: 10.1016/j.ultsonch.2019.05.017. Epub 2019 May 16.
In this study, we used flotation tests, Fourier transform infrared spectroscopy (FTIR), zeta potential, X-ray photoelectron spectroscopy (XPS), and microcalorimetry measurements to investigate the flotation and possible adsorption mechanisms of the ilmenite surface before and after ultrasonic pre-treatment. Flotation results show that under optimum conditions, the promotion effect of sonication on ilmenite is remarkable. The maximum recovery is 89.54% for ultrasonicated ilmenite at a pH of 4-5. For pH of 8-9, recovery increased again to 66.34%. Microcalorimetry indicates that the adsorption-driven heat release (-Q) is higher for ultrasonicated ilmenite than for raw one. After pre-treatment, the iso-electric point (IEP) changed from pH 6.2 to pH 4.2. FTIR spectra and zeta potential measurements indicated that metal ions as active sites on the ilmenite surface are probably changed by the ultrasonic treatment. XPS analysis shows that ultrasonic treatment can promotes the oxidation of Fe to Fe and improves the solubilization of Ca and Mg in the pH range of 4-5. Under weakly alkaline condition, ultrasound also can make Ca and Mg re-absorb onto the ilmenite surface as main active sites.
在本研究中，我们使用浮选试验、傅里叶变换红外光谱（FTIR）、zeta电位、X射线光电子能谱（XPS）和微量热法测量来研究超声预处理前后钛铁矿表面的浮选及可能的吸附机制。浮选结果表明，在最佳条件下，超声处理对钛铁矿的促进作用显著。超声处理后的钛铁矿在pH值为4 - 5时最大回收率为89.54%。在pH值为8 - 9时，回收率再次提高到66.34%。微量热法表明，超声处理后的钛铁矿吸附驱动的热释放（-Q）高于未处理的原矿。预处理后，等电点（IEP）从pH 6.2变为pH 4.2。FTIR光谱和zeta电位测量表明，钛铁矿表面作为活性位点的金属离子可能因超声处理而发生变化。XPS分析表明，超声处理可促进Fe氧化为Fe，并在pH值为4 - 5的范围内提高Ca和Mg的溶解性。在弱碱性条件下，超声也可使Ca和Mg作为主要活性位点重新吸附到钛铁矿表面。
