Recent progress on research of molybdenite flotation: A review

Experimental and Mechanistic Study on Flotation Separation of Chalcopyrite and Molybdenite Using the Novel Depressant 2-Mercapto-6-Methylpyrimidin-4-ol

Chalcopyrite and molybdenite are vital strategic metal resources. Due to their close association in ores, flotation methods are commonly used for separation. The flotation separation method primarily employs the "copper depression and molybdenum flotation" process, enhancing the wettability difference between chalcopyrite and molybdenite through a chalcopyrite depressant. Traditional depressants often face challenges, including low selectivity, high dosage requirements, poor stability, and significant environmental pollution, highlighting the need for new, highly selective green reagents. This study introduces the novel chalcopyrite depressant 2-mercapto-6-methylpyrimidin-4-ol (MMO) for flotation separation. The influence of MMO on chalcopyrite and molybdenite flotation recovery was examined through microflotation experiments. Additionally, the effects of MMO and ethyl xanthate on surface wettability were assessed via contact angle measurements. The adsorption microstructure and interaction mechanism of MMO on chalcopyrite were elucidated using FT-IR, TOF-SIMS, and XPS analyses and DFT simulations. Results indicate that MMO enhances chalcopyrite hydrophilicity and exhibits a strong depressing effect on its flotation, while minimally impacting molybdenite recovery. Thus, it serves as an effective depressant. During adsorption, N and S atoms in MMO donate electrons to Fe and Cu ions, leading to triple bond adsorption and a stable chelate structure. These findings are crucial for achieving a greener and more efficient flotation separation of copper and molybdenum.

Hydrophilic Modification of Macroscopically Hydrophobic Mineral Talc and Its Specific Application in Flotation

Sodium diethyldithiocarbamate (DDTC), a common collector used to enhance the hydrophobicity of minerals in froth flotation, nevertheless weakens the hydrophobicity of the talc surface. To rationalize this anomaly, the interactions of a hydrophobic alkyl group and hydrophilic mineralophilic group (-NCS2-) of heteropolar surfactant DDTC, and a water molecule with the talc (001) surface, were investigated. Herein, DFT simulations found that the talc (001) surface features natural hydrophobicity determined by the competition between adhesion (surface water) and cohesion (water-water interactions). The interaction of the hydrophobic alkyl group of DDTC with the talc surface is more favorable compared to that of the -NCS2- group and H2O, favoring the hydrophilic modification of the talc surface. Additionally, adsorption isotherms, time-of-flight secondary ion mass spectrometry (ToF-SIMS), microflotation tests, and contact angle measurements also indicate that the differences in adsorption orientation of the heteropolar surfactant DDTC on the talc surface enhance the hydrophilicity of the talc surface, leading to a decreased recovery of the talc. This study provides crucial surface chemistry evidence for the selective adsorption of heteropolar surfactants and contributes to the understanding of the mechanism for the efficient flotation separation of molybdenite from talc.