The utilization of citric acid as a depressant for the flotation separation of barite from fluorite

To achieve the efficient flotation separation of barite from fluorite, citric acid (CA) was utilized as a depressant for fluorite in this study. Microflotation showed that both fluorite and barite had good floatability when using sodium oleate (NaOl) as the collector, while fluorite was selectively depressed when using CA as the depressant. Real ore flotation confirmed that CA could be used as a depressant to successfully separate barite from fluorite. Adsorption experiments and ICP-AES tests revealed that the addition of CA caused the dissolution of Ca2+ from the fluorite surface, but it had no significant effects on Ba2+ on the barite surface. SEM-EDS analysis further revealed a reduction in the Ca/F ratio on the fluorite surface with the addition of CA. Zeta potential measurements indicated that NaOl could be adsorbed onto the barite surface rather than the fluorite surface in the presence of CA. Solution chemistry calculations demonstrated that L3- more easily interacts with Ca2+ than Ba2+ at pH 8.5. These findings indicated that the selective inhibition of fluorite by CA could be attributed to the dissolution of Ca2+ from the mineral surface, which reduced the number of activated sites for the adsorption of NaOl.