Abstract

It is difficult to separate scheelite especially from fluorite with fatty acid collectors because the adsorption mechanism of these collectors occurs through chemisorption of the oleate ion onto the mineral surface. A simplified flotation process using Pb-BHA complexes was developed to replace the energy-inefficient Petrov’s process of using a fatty acid, increasing the recovery of scheelite and reducing the cost. The relationship between surface chemical properties (crystal chemistry, solubility, and Zeta potential) of minerals and flotation by using a fatty acid or Pb-BHA complexes was studied in detail to provide new insights into the selective separation mechanism. The results indicate that the scheelite surface exposes more O atoms than Ca and that they are negatively charged due to the anisometric dissolution of Ca and WO4, which provides the possibility for separation using selective interfacial reaction. The Fourier Transform infrared spectroscopy (FTIR) and Zeta potential results indicate that both chemical and electrostatic adsorption play an important role in the adsorption of Pb-BHA complexes on the scheelite surface. The X-ray photoelectron spectroscopy (XPS) results of the atomic composition and binding energies confirmed the presence of the adsorbed Pb-BHA complexes and that Pb, O and Ca may be the active adsorption sites. Therefore, scheelite was able to be collected by forming either a Ca-O-Pbcollector or W-O-Pb-collector (BHA). However, fluorite was only able to be collected by a fatty acid collector and colloidal [H2SiO3]n −, and a high temperature was needed improve the selective desorption of the adsorbed fatty acid collector by forming Ca-[H2SiO3]n − on the fluorite surface, resulting in serious problems in industry. However, the Pb-BHA complexes significantly contribute to improving the recovery of scheelite minerals, simplifying the flotation process, and circulation of the residual reagents and water.

Keywords: 

Pb-BHA complexes 

Fatty acid 

Scheelite 

Fluorite 

Petrov's process 

Water treatment