The presence of iron (Fe) and copper (Cu) negatively impacts molybdenum (Mo) recoveries in existing metallurgical processes. This study investigated the speciation of Mo in highly acidic solutions, exploring the removal of Fe and Cu from low-grade molybdenum calcine through acid washing. The species distribution diagram for the Mo-H 2 O system indicated that Mo predominantly existed as a monomeric and dimeric species at pH < 0. Acid washing experiment results indicated that 92 % of Fe and 97 % of Cu were removed, and the Mo loss rate remained <4 %. Furthermore, optimized conditions included 3 M H 2 SO 4 , 150 min, 90 °C, and a liquid–solid ratio of 2:1. Characterization through X-ray diffraction (XRD) and scanning electron microscopy- energy dispersion spectrum (SEM-EDS) analysis of the acid washing residue indicated that Mo existed in the form of MoO 3 . Furthermore, solvent extraction successfully recovered over 97 % of Mo from the acid washing solution. Recycling the raffinate into the acid washing process was found to reduce overall process costs. This study offered a practical and economical approach, optimizing the utilization of Mo resources by addressing challenges associated with Fe and Cu contents in existing processes.
Zhiqiang Zhao,Yangjia Hu,Jianhua Chen,Yangge Zhu,Liang Lu,Wei Xiong,Sigang Luo
In order to achieve the effective separation of copper-molybdenum in the presence of xanthate and kerosene, carrageenan was explored as a novel environmentally friendly molybdenite depressant in this work. The flotation behavior of molybdenite was studied by micro-flotation tests, and the depression mechanism was investigated through zeta potential, Fourier Transform Infrared Spectroscopy (FTIR) and atomic force microscope (AFM) analysis. The flotation results showed that molybdenite was significantly depressed by carrageenan in the pH range of 6–12 even in the presence of xanthate and kerosene. Zeta potential, FTIR and AFM measurement demonstrated that carrageenan could adsorb strongly on the molybdenite surface and change the surface wettability of molybdenite, thus significantly reducing the floatability of molybdenite.Keywords:flotation;molybdenite;separation;carrageenan;depressant
It is challenging to separate between molybdenite and chalcopyrite due to their comparable hydrophobic characteristics. Inorganic depressants were previously used to separate two minerals, but the results were unsatisfactory and polluted the environment. In this study, the molybdenite and chalcopyrite were separated using a highly effective and ecologically safe depressant, 2,4-Diamino-6-hydroxypyrimidine (DAHP). According to the single mineral experiment, chalcopyrite is totally depressed while molybdenite has superior floatability. The efficacy of DAHP as the depressant was validated by further artificially mixed mineral flotation experiments, indicating the possibility of separating chalcopyrite and molybdenite. The adsorption capacity experiment results showed that the adsorption capacity of DAHP on the surface of chalcopyrite was greater than that on the surface of molybdenite. Zeta potential experiment results show that DAHP is adsorbed on the surface of chalcopyrite and molybdenite through static electrostatic interactions . X-ray photoelectron spectroscopy (XPS) experiment results show that DAHP is mainly adsorbed on chalcopyrite surface through –NH 3 + group, which hinders the adsorption of kerosene. The electrostatic contact between DAHP and molybdenite has the least effect on kerosene adsorption. This study shows that DAHP has the potential to separate chalcopyrite and molybdenite as an efficient and environmentally friendly depressant.
To date, lime-free flotation processes are increasingly advocated due to many problems caused by the traditional process using lime (CaO) as a depressant and xanthate (BX) as a collector. In this work, we developed a combination of pyrogallic acid (PGA) and o-isopropyl ethylthiocarbamate (Z200) as an eco-friendly alternative to the lime-xanthate process for chalcopyrite-molybdenite (ccp-mlb) flotation. Roughing flotation experiments showed that this process yields ccp-mlb concentrate with similar recovery and grade of Cu and Mo as in the traditional lime-xanthate process. However, the huge advantage of the novel process is that it requires ten times lower dosages of sodium sulfide in the subsequent separation of ccp-mlb concentrate. The ab initio calculations explained this trend at the atomistic level, where hydrogen sulfide ions could desorb collector more easily from the Z200@ccp complex compared with BX@ccp. The same method could be applied for environmentally friendly separations of other resources with similar composition.
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