Flotation separation of scheelite and apatite by polysaccharide depressant xanthan gum

Abstract Tungsten is a crucial rare metal with extensive application in modern industries and scheelite is the major resource for tungsten production. In this work, xanthan gum (XG), a non-toxic, environmentally friendly polysaccharide, was explored as a depressant of apatite during the scheelite flotation. The results of single mineral flotation and artificial mixed minerals flotation showed that XG exhibited efficient selective depressive effect on apatite rather than on scheelite. The Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis indicated that the chelation action between the –COO– groups and the Ca on apatite surface was responsible for XG chelating adsorption. The firm XG chemisorption on apatite surface hindered subsequent sodium oleate (NaOl) chemisorption. Due to fewer available surface Ca sites and intenser anions group electronegativity on scheelite, the XG adsorption on scheelite surface was weak and it exhibited little effect on following NaOl chemisorption. As a result, the flotation separation of scheelite from apatite was achieved using XG as depressant and NaOl as collector.