New insights into the oleate flotation response of feldspar particles of different sizes: Anisotropic adsorption model

Longhua Xu; Jia Tian; Houqin Wu; Wei Deng; Yaohui Yang; Wei Sun; Zhiyong Gao; Yuehua Hu

doi:10.1016/j.jcis.2017.06.009

New insights into the oleate flotation response of feldspar particles of different sizes: Anisotropic adsorption model

J Colloid Interface Sci. 2017 Nov 1:505:500-508. doi: 10.1016/j.jcis.2017.06.009. Epub 2017 Jun 8.

Authors

Longhua Xu¹, Jia Tian², Houqin Wu³, Wei Deng⁴, Yaohui Yang⁴, Wei Sun⁵, Zhiyong Gao⁵, Yuehua Hu⁶

Affiliations

¹ Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education, Southwest University of Science and Technology, Mianyang, Sichuan 621010, PR China; School of Resources Processing and Bioengineering, Central South University, Changsha, Hunan 410083, PR China; State Key Laboratory of Mineral Processing, Beijing 102628, PR China. Electronic address: neuxulonghua@163.com.
² Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education, Southwest University of Science and Technology, Mianyang, Sichuan 621010, PR China; School of Resources Processing and Bioengineering, Central South University, Changsha, Hunan 410083, PR China.
³ Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education, Southwest University of Science and Technology, Mianyang, Sichuan 621010, PR China.
⁴ Institute of Multipurpose Utilization of Mineral Resources, Chinese Academy of Geological Science, Chengdu, Sichuan 610041, PR China.
⁵ School of Resources Processing and Bioengineering, Central South University, Changsha, Hunan 410083, PR China.
⁶ School of Resources Processing and Bioengineering, Central South University, Changsha, Hunan 410083, PR China. Electronic address: hyh@csu.edu.cn.

PMID: 28641174
DOI: 10.1016/j.jcis.2017.06.009

Abstract

The anisotropic adsorption of sodium oleate (NaOL) on feldspar surfaces was investigated to elucidate the different flotation properties of feldspar particles of four different size ranges. Microflotation experiments showed that the feldspar flotation recovery of particles with sizes spanning different ranges decreased in the order 0-19>19-38>45-75>38-45μm. Zeta potential and FTIR measurements showed that NaOL was chemically adsorbed on the Al sites of the feldspar surface. The anisotropic surface energies and broken bond densities estimated by density functional theory calculations showed that, although feldspar mostly exposed (010) and (001) surfaces, only the (001) surfaces contained the Al sites needed for NaOL adsorption. The interaction energies calculated by molecular dynamics simulations confirmed the more favorable NaOL adsorption on (001) than (010) surfaces, which may represent the main cause for the anisotropic NaOL adsorption on feldspar particles of different sizes. SEM measurements showed that the main exposed surfaces on coarse and fine feldspar particles were the side (010) and basal (001) ones, respectively. A higher fraction of Al-rich (001) surfaces is exposed on fine feldspar particles, resulting in better floatability compared with coarse particles. XPS and adsorption measurements confirmed that the Al content on the feldspar surface varied with the particle size, explaining the different NaOL flotation of feldspar particles of different sizes. Therefore, the present results suggest that coarsely ground ore should be used for the separation of feldspar gangue minerals. Further improvements in the flotation separation of feldspar from associated valuable minerals can be achieved through selective comminution or grinding processes favoring the exposure of (010) surfaces.

Keywords: Anisotropic adsorption; Feldspar; Flotation; Particle size; Surface crystal chemistry.