A novel technique for microcrystalline graphite beneficiation based on alkali-acid leaching process

作者:Wang, Hao; Feng, Qiming; Liu, Kun*; Zuo, Kesheng; Tang, Xuekun
来源:Separation Science and Technology (Philadelphia), 2018, 53(6): 982-989.
DOI:10.1080/01496395.2017.1405986

摘要

Purification of microcrystalline graphite concentrate with alkali-acid leaching process was studied in this paper. The influences of alkali leaching temperature, NaOH concentration, alkali leaching time, HCl consumption, liquid-solid ratio, and acid leaching times were investigated respectively. Final refined products with carbon content in the range of 90.88%-98.36% were prepared from flotation concentrate with carbon content of 84.27%. In addition, the volatile content in the end product was reduced from 2.7% to 1.17%. X-ray diffraction (XRD) and scanning electron microscope equipped with energy-dispersive X-ray spectroscopy (SEM-EDS) analysis revealed that the crystal structure and morphology of graphite had no obvious change when impurities composed of Si, Al, and O were almost completely removed. Alkali-acid leaching process could enhance the carbon content of microcrystalline graphite to a higher level than the traditional method of alkali roasting-acid leaching process.