A modified co-polyacrylamide to depress molybdenite in Cu/Mo separation and its competitive adsorption mechanism between reagents

• Published in: Separation and purification technology 2024-06, Vol.337, p.126239, Article 126239
• Main Authors: Zhang, Xingrong, Jiang, Xinyao, Luo, Anruo, Chen, Jianhua, Meng, Yao
• Format: Article
• Language: English
• Subjects: Chalcopyrite; Flotation separation; Molybdenite; PAMDTC depressant; Physical adsorption
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2023.126239

•PAMDTC showed a strong depressing performance on molybdenite when using DEDTC collector.•PAMDTC could prevent the DEDTC attachment on molybdenite surface by competitive adsorption.•DS of the dithiocarbamate group in PAMDTC would greatly influence its depression power to minerals.•PAMDTC adsorbed on molybdenite surface mainly by physical adsorption based on DFT simulations. In this research, a co-poly(acrylamide-allyldithiocarbamate) (PAMDTC) depressant was prepared by modifying polyacrylamide (PAM) and firstly utilized to depress molybdenite in Cu/Mo flotation separation. PAMDTC exhibited superior depression efficacy on molybdenite to unmodified polyacrylamide (PAM) based on micro-flotation tests results when using diethyldithiocarbamate (DEDTC) as the collector. In addition, it was found that the degree of substitution (DS) of allyldithiocarbamate group in PAMDTC would greatly influence its depression power and selectivity to minerals as an important factor. Finally, a competitive adsorption between PAMDTC and DEDTC on molybdenite surface was discovered and detected by adsorption tests, contact angle measurements, FTIR, XPS analysis and DFT simulations. The findings from adsorption tests and contact angle measurements implied that PAMDTC could prevent DEDTC collector adsorbing on molybdenite surface, but had few influences on the adsorption of DEDTC on chalcopyrite surface, providing adequate evidence of a competitive adsorption. Moreover, FTIR, XPS and DFT simulation analysis results further confirmed that PAMDTC physically adsorbed on molybdenite surface, simultaneously, it showed a stronger adsorption than DEDTC collector judging from these results of bond length, adsorption energy and electron density in DFT simulations.