Abstract: Scheelite is one of the main sources of tungsten industrial raw materials，but its gangues are mostly fluorite，calcite and quartz.It is difficult to obtain qualified concentrate index because of the similar surface properties.Through flotation test for pure mineral，FTIR analysis，contact angle analysis and Zeta potential analysis，the adsorption behavior and mechanism of carboxylated chitosan，sodium lignosulfonate，sodium humate and combined depressents in the flotation separation of scheelite from fluorite and calcite at room temperature were studied.The flotation test results showed that carboxylated chitosan，sodium lignosulfonate and sodium humate strongly restrained fluorite and calcite，scheelite also has a slight effect，and the difference of floatability is small.Sodium lignosulfonate and sodium humate were combined according to the mass ratio of 4∶1 and named DWC-1 as an depressent for flotation.There was a great difference in the flotability between scheelite and the two gangues.Infrared spectrum，contact angle and Zeta potential analysis showed that the adsorption degree of DWC-1 on scheelite surface is much less than that of fluorite and calcite，and the main adsorption form is chemical adsorption.

Key words: scheelite, combined depressent, organic depressent, flotation