Effects and Mechanism of Fe 3+ on Flotation Separation of Feldspar and Epidote with Sodium Oleate at Natural pH

Separations

article

Weiwei Zeng¹  Guofan Zhang¹  Qing Shi¹  Leming Ou¹ 

[1] School of Minerals Processing and Bioengineering, Central South University;Department of Resources and Environment, Hunan Nonferrous Metals Vocational and Technical College

关键词: feldspar;    epidote;    Fe3+;    sodium oleate;    natural pH;   

DOI  :  10.21037/jtd-21-195

学科分类：社会科学、人文和艺术（综合）

来源: mdpi

【 摘 要 】

The most common beneficiation method for feldspar is flotation with a cationic (amine)collector under acidic conditions. However, there are several disadvantages to this, such as environmental pollution and equipment corrosion. In order to resolve such problems, it is important tostudy the flotation of feldspar using anionic collectors under natural pH conditions. The purposeof this paper is to study the effects and mechanism of Fe3+ on flotation separation of feldspar andepidote using sodium oleate (NaOL) at a natural pH. Through flotation experiments, adsorptionmeasurements, zeta potential testing, FTIR analysis and X-ray photoelectron spectroscopy (XPS),the mechanism of Fe3+ on the surface of feldspar and epidote is revealed, and the reason behindthe difference in flotation of the two minerals is discussed. The flotation test results show that Fe3+can significantly improve the flotation behavior of minerals when NaOL is used as a collector undernatural pH, and the highest recovery rates of feldspar and epidote are 90% and 43%, respectively.Analysis of the solution and adsorption measurement results show that Fe3+ is adsorbed on theminerals0surface in the form of Fe(OH)3, which promotes the adsorption of NaOL on the minerals’surface through Fe(OH)3, activating the flotation of feldspar and epidote. The difference in adsorption of Fe3+ between feldspar and epidote is the reason for this difference in flotation behavior. Theresults of the zeta potentials show that after being treated with Fe3+, the electrostatic adsorptionof NaOL displays a significant negative shift on the surface of feldspar, while there is almost noelectrostatic adsorption of NaOL on the surface of Fe3+-treated epidote. FTIR analysis confirmed thatthe difference in the adsorption of Fe3+ and NaOL on the surface of feldspar and epidote is due to thefact that there are more active particles (metal bonds) on the surface of feldspar than on the surfaceof epidote, and the properties of these metal bonds can be changed by Fe3+, which allows NaOL tobe more easily adsorbed on the mineral surface through –COO−. The possible adsorption form is“mineral-Fe3+–COO−“. Compared with the infrared spectrum of epidote, there is a new absorptionpeak at 1713.68 cm−1, which can be attributed to the C=O characteristic peak of NaOL in the infraredspectrum of Fe3+–NaOL-treated feldspar, which is why the floatability of feldspar is better thanepidote. XPS confirmed that the Fe on the surface of feldspar is Fe3+ in the form of Fe(OH)3, while Feon the surface of epidote is mainly Fe2O3(Fe–O) contained in mineral crystals. Furthermore, there isless adsorption of Fe3+ on the surface of epidote, and this discrepancy leads to the difference in theadsorption of NaOL on the minerals’ surface, which itself leads to the difference in flotation behaviorbetween feldspar and epidote. These findings indicate that the flotation separation of feldspar andepidote can be achieved using Fe3+ and NaOL under natural pH. This study may provide a referencefor the flotation mechanism of feldspar and epidote under natural pH.

【 授权许可】

CC BY