Abstract: The flotation separation of scheelite and calcite remains difficult because of their similar surface active sites
and physicochemical properties. In order to explore efficient and environmentally friendly inhibitor of calcite in scheelite flotation,
the selective inhibition effect of sodium lignosulfonate carboxymethylation modifier (SLS) on calcite was discussed
through single mineral flotation test and artificial mixed mineral flotation test,and its selective inhibition mechanism was explored
through UV-Vis,adsorption capacity test,Zeta potential test,Fourier transform infrared spectroscopy (FTIR) test and Xray
photoelectron spectroscopy (XPS) test. The flotation test results indicated that under specific conditions,2. 5 mg/ L SLS
could increase the flotation recovery difference between scheelite and calcite from 63. 40 percentage points to 72. 28 percentage
points,and the flotation separation effect was significantly better than that before modification. UV-Vis analysis showed that the
conjugated structure of the carboxymethylation modifier changed significantly within the π-π∗ transition wavelength range. The
adsorption capacity and Zeta potential determination results demonstrated that SLS has a large adsorption capacity and a strong
effect on the calcite surface,indicated selective inhibition effect of SLS in calcite. FTIR and XPS analysis results revealed that
SLS can inhibit calcite through chemisorption between active groups such as carboxyl,hydroxyl,sulfonic acid,and the active
site Ca2+ on the calcite surface,thereby achieving the efficient separation of scheelite and calcite.

Key words: sodium lignosulfonate,carboxymethylation modification,flotation separation,inhibitor,calcite,scheelite