Synergistic effect of microwave irradiation and CaF₂ on vanadium leaching

Abstract

The effect and mechanism of microwave irradiation on vanadium leaching were studied via a comparison between microwave heating and conventional heating. The results show a synergistic effect of microwave irradiation and calcium fluoride (CaF₂) on the vanadium leaching efficiency. It is confirmed that the vanadium leaching process can be improved by microwave irradiation when CaF₂ is present. The leaching rate of vanadium under microwave irradiation is increased by 8%–15% when 5wt% CaF₂ is added; by contrast, in the absence of CaF₂, the leaching rate is almost unaffected compared to that by conventional heating. Morphological analysis reveals that the particles are gradually eroded by acid under microwave irradiation, whereas some of the fine particles in samples subjected to conventional heating are tightly covered by a flocculent silicate product. Moreover, a large amount of Al and V and a small amount of Si are dissolved from samples under microwave heating, as revealed by the elemental analysis of leachates. Fourier transform infrared spectroscopic analysis also indicates a higher mass transfer coefficient in the diffusion layer of the raw material by microwave irradiation. When CaF₂ is present, the reaction energy barrier is lowered and the leaching process is controlled by the tightly covered product layer, resulting in a prominent effect of microwave irradiation.

Keywords

vanadium extraction / leaching / microwave irradiation / calcium fluoride / synergistic effects

References

[1] Zhang Y.M., Bao S.X., Liu T., Chen T.J., Huang J. The technology of extracting vanadium from stone coal in China: history, current status and future prospects. Hydrometallurgy, 2011, 109(1-2): 116.

[2] Zhang G.Q., Zhang T.A., Lü G.Z., Zhang Y., Liu Y., Liu Z.L. Extraction of vanadium from vanadium slag by high pressure oxidative acid leaching. Int. J. Miner. Metall. Mater., 2015, 22(1): 21.

[3] Yuan Y.Z., Zhang Y.M., Liu T., Chen T.J. Comparison of the mechanisms of microwave roasting and conventional roasting and of their effects on vanadium extraction from stone coal. Int. J. Miner. Metall. Mater., 2015, 22(5): 476.

[4] Zhai X.J., Fu Y., Zhang X., Ma L.Z., Xie F. Intensification of sulphation and pressure acid leaching of nickel laterite by microwave radiation. Hydrometallurgy, 2009, 99(3-4): 189.

[5] Hu Y.J., Zhang Y.M., Bao S.X., Liu T. Effects of the mineral phase and valence of vanadium on vanadium extraction from stone coal. Int. J. Miner. Metall. Mater., 2012, 19(10): 893.

[6] Li X.S., Xie B. Extraction of vanadium from high calcium vanadium slag using direct roasting and soda leaching. Int. J. Miner. Metall. Mater., 2012, 19(7): 595.

[7] Zhu X.B., Zhang Y.M., Huang J., Liu T., Wang Y. A kinetics study of multi-stage counter-current circulation acid leaching of vanadium from stone coal. Int. J. Miner. Process., 2012, 114-117, 1.

[8] Li H.Y., Wang K., Hua W.H., Yang Z., Zhou W., Xie B. Selective leaching of vanadium in calcification-roasted vanadium slag by ammonium carbonate. Hydrometallurgy, 2016, 160, 18.

[9] Wang F., Zhang Y.M., Huang J., Liu T., Wang Y., Yang X., Zhao J. Mechanisms of aid-leaching reagent calcium fluoride in the extracting vanadium processes from stone coal. Rare Met., 2013, 32(1): 57.

[10] Wang F., Zhang Y.M., Liu T., Huang J., Zhao J., Zhang G.B., Liu J. Comparison of direct acid leaching process and blank roasting acid leaching process in extracting vanadium from stone coal. Int. J. Miner. Process., 2014, 128, 40.

[11] Xue N.N., Zhang Y.M., Liu T., Huang J. Study of the dissolution behavior of muscovite in stone coal by oxygen pressure acid leaching. Metall. Mater. Trans. B, 2016, 47(1): 694.

[12] Terry B. The acid decomposition of silicate minerals: Part I.^Reactivities and modes of dissolution of silicates. Hydrometallurgy, 1983, 10(2): 135.

[13] Zhang G.Q., Zhang T.A., Lü G.Z., Zhang Y., Liu Y., Zhang W.G. Effects of microwave roasting on the kinetics of extracting vanadium from vanadium slag. JOM, 2016, 68(2): 577.

[14] Al-Harahsheh M., Kingman S. The influence of microwaves on the leaching of sphalerite in ferric chloride. Chem. Eng. Process., 2007, 46(10): 883.

[15] Bayca S.U. Microwave radiation leaching of colemanite in sulfuric acid solutions. Sep. Purif. Technol., 2013, 105, 24.

[16] Aydoğan S., Erdemoğlu M., Uçar G., Aras A. Kinetics of galena dissolution in nitric acid solutions with hydrogen peroxide. Hydrometallurgy, 2007, 88(1-4): 52.

[17] Wang N.N., Wang P. Study and application status of microwave in organic wastewater treatment: a review. Chem. Eng. J., 2016, 283(1): 193.

[18] Shen X.M., Li L.S., Wu Z.J., Lü H.H., Lü J. Ultrasonic-assisted acid leaching of indium from blast furnace sludge. Metall. Mater. Trans. B, 2013, 44(6): 1324.

[19] Chen G., Chen J., Zhang Z.Y., Guo S.H., Zhang Z.B., Peng J.H., Srinivasakannan C., Li X.Q., Zhuang Y.K., Xu Z.M. Leaching of refractory gold ores by microwave irradiation: comparison with conventional leaching. Metallurgist, 2013, 57(7): 647.

[20] Pinto I.S.S., Soares H.M.V.M. Microwave-assisted selective leaching of nickel from spent hydrodesulphurization catalyst: a comparative study between sulphuric and organic acids. Hydrometallurgy, 2013, 140, 20.

[21] Pinto I.S.S., Soares H.M.V.M. Selective leaching of molybdenum from spent hydrodesulphurization catalysts using ultrasound and microwave methods. Hydrometallurgy, 2012, 129-130, 19.

[22] Zhang L.Y., Mo J.M., Li X.H., Pan L.P., Liang X.Y., Wei G.T. A kinetics study of indium leaching from indium-bearing zinc ferrite under microwave heating. Metall. Mater. Trans. B, 2013, 44(6): 1329.

[23] Ma Z.Y., Yang H.Y., Huang S.T., Lü Y., Xiong L. Ultra fast microwave-assisted leaching for the recovery of copper and tellurium from copper anode slime. Int. J. Miner. Metall. Mater., 2015, 22(6): 582.

[24] Zhao J., Zhang Y.M., Huang J., Liu T., Wang F., Wang Y., Liu J. Study on the impact of F-contained leaching agent on acid leaching of vanadium from stone coal. Met Mine, 2013, 1, 90.

[25] Wen L., Liang W.X., Zhang Z.G., Huang J.C. The Infrared Spectroscopy of Minerals, 1989, Chongqing, Chongqing University Press, 89.

[26] Kaufhold D., Hein M., Dohrmann R., Ufer K. Quantification of the mineralogical composition of clays using FTIR spectroscopy. Vib. Spectrosc., 2012, 59, 29.

[27] Diaz M., LaPerche V., Harsh J., Prost R. Far infrared spectra of K⁺ in the dioctahedral and trioctahedral mixed-layer minerals. Am. Miner., 2002, 87(8-9): 1207.

[28] Prost R., Laperche V. Far-infrared study of potassium in micas. Clays Clay Miner., 1990, 38(4): 351.

[29] Laperche V., Prost R. Assignment of the far-infrared absorption bands of K in micas. Clays Clay Miner., 1991, 39(3): 281.

[30] Friedrich F., Gasharova B., Mathis Y.L., Nüesch R., Weidler P.G. Far-infrared spectroscopy of interlayer vibrations of Cu(II), Mg(II), Zn(II), and Al(III) intercalated muscovite. Appl. Spectrosc., 2006, 60(7): 723.

[31] Ritz M., Vaculíková L., Plevová E. Identification of clay minerals by infrared spectroscopy and discriminant analysis. Appl. Spectrosc., 2010, 64(12): 1379.