Characterization of the Impurity Phases in Phosphogypsum by the EBSD-XPS Method
TANG Ming-zhu1, WANG Zhi-ying1, WANG Yun-shan2*, BAO Wei-jun2, YANG Gang2, SUN Yong3
1. School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300130, China
2. National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
3. Key Laboratory of Carbonaceous Wastes Processing and Process Intensification of Zhejiang Province, The University of Nottingham Ningbo China, Ningbo 315100, China
Abstract：Phosphogypsum (PG) is a solid by product generated from the wet phosphoric acid process. A broad spectrum of compositions, including phosphorus, fluorine, silicon, and other hazardous impurities in the PG matrix significantly affect the PG’s quality as the end-products, let alone its persistent ecological and environmental impacts caused by the huge quantity of storage and disposal. Therefore, identification of its impurity phases of PG becomes pivotal. Not only it provides the theoretical guidance for the separation processing but it also sheds insightful lightonits value-added utilization. Different spectral characterization techniques were deployed to unveil its impurity phases in the PG. The X-ray fluorescence spectroscopy (XRF) results show that the elements including P, Si, F and Al remain at a relatively higher level, while the elements such as Ba, Fe and Mg are present at the trace level. The X-ray diffraction spectroscopy (XRD) spectrum presents the dominant crystallite gypsum, whilethe crystal spectrum of other impurities is hardly observed. The electron backscatter diffraction (EBSD) by scanning electron microscope (SEM) results indicate the impurities in the form of silicon dioxide, sodium fluorosilicate, potassium fluorosilicate, calcium fluorophosphate, calcium fluoride, barium sulfate, iron sulfide, and aluminum oxide, etc. These compositions exist as the singular metallic oxides and present in the binary, ternary and multiple metallic oxides complex, making the impurities as a series ofthe composites in the crystallite PG framework. In order to investigate the surface binding energy of the prepared PG, X-ray photoelectron spectroscopy (XPS) was also employed. The results indicate the complexities of the impurities as in the form of calcium silicate,aluminum fluoride, magnesium fluoride, aluminum sulfate, aluminum phosphate, calcium phosphate, calcium hydrogen phosphate and calcium dihydrogen phosphate. In addition, the XPS result also shows the close featured positions, which underpins the characteristic peaks of calcium phosphate, calcium hydrogen phosphate, calcium dihydrogen phosphate and calcium fluorophosphates, indicating their relative similar surface bonding energy. To the best of the author’s knowledge, thecombined characterization techniques using both EBSD and XPS, have been rarely applied in the elucidation of complex phase of the impurities of PG generated from the phosphoric acid process. The inherent advantages of using this proposed hybrid spectrum technique withan accurate establishment of the structure-activity relationship between the impurity phases and calcium sulfate crystal, the comprehensive constructing impurity phases, will pave a new way for the impurity phase characterization, value-added conversion, and integrated utilization of PG.
唐明珠，王志英，王云山，包炜军，杨 刚，孙 勇. EBSD-XPS法分析磷石膏中杂质物相[J]. 光谱学与光谱分析, 2022, 42(01): 136-140.
TANG Ming-zhu, WANG Zhi-ying, WANG Yun-shan, BAO Wei-jun, YANG Gang, SUN Yong. Characterization of the Impurity Phases in Phosphogypsum by the EBSD-XPS Method. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2022, 42(01): 136-140.
[1] WANG Ai-wen，CHEN De-yu，HUANG Tao（王艾文，陈德玉，黄 滔）. Non-Metallic Mines（非金属矿），2020，43（4）：84.
[2] Ma Baoguo，Lu Wenda，Su Ying，et al. Journal of Cleaner Production，2017，195：396.
[3] Tebogo Mashifana，Freeman Ntuli，Felix Okonta. South Afrian Journal of Chemical Engineering，2019，27：1.
[4] Alaa M Rashad. Journal of Cleaner Production，2017，166：732.
[5] Yassine Ennaciri，Llham Zdah，Hanan EI Alaoui-Belghiti. Chemical Engineering Communications，2020，207：382.
[6] ZHAO Hong-tao，BAO Wei-jun，SUN Zhen-hua，et al（赵红涛，包炜军，孙振华，等）. Chemical Industry and Engineering Paogress（化工进展），2017，36（4）：1240.
[7] Dalia Nizeviciene，Danute Vaiciukyniene，Boguslaw Michalik，et al. Construction and Building Materials，2018，180：134.
[8] GAO Shang，HUANG Meng-shi，WANG Jun-zhao，et al（高 尚，黄梦诗，王君兆，等）. Materials Science and Technology（材料科学与工艺），2020，28（4）：1.
[9] Canovas C R，Chapron S，Arrachart G，et al. Journal of Cleaner Production，2019，219：225.
[10] Bruckner R，Chun H U，Goretzki H，et al. Journal of Non-Crystalline Solids，1980，42：49.
[11] Kallury K M R，Cheung M，Ghaemmaghami V，et al. Colloids and Surfaces，1992，63：1.
[12] Jiang Yunbin，Kideok D Kwon，Wang Shaofeng，et al. Science of the Total Environment，2019，696：1.
[13] Wagner C D，Passoja D E，Hillery H F，et al. J. Vac. Sci. Technol.，1982，21：993.
[14] Hess A，Kemnitz E，Lippitz A，et al. Journal of Catalysis，1994，148：270.
