Abstract: In order to separate fluorite and calcite more effectively by flotation,the effects of carboxymethyl cellulose (CMC) in the flotation separation of fluorite and calcite was studied by flotation test and various measurements such as contact angle,zeta potential,microcalorimetry,thereby revealing the selective inhibition mechanism for fluorite and calcite by CMC.The results showed that the CMC concentration of 20 mg/L depressed calcite efficiently and maximized the flotation separation at pH=8.Due to the high adsorption of —RCOO— dissociated from the CMC component on the calcite surface,the calcite surface only adsorbed a small quantity of oleate ions.At the same time,an apparent negative shift of calcite zeta potential was observed,leading to a greater hydrophilicity,consistent with the contact angle measurements.The proposed adsorption model indicated that the diminished active Ca²⁺ sites on the calcite surface was the main reason for its depression,with a reaction order of n=1.

Key words: carboxymethyl cellulose, fluorite, calcite, flotation separation, depression