Decomposition mechanism of chromite in sulfuric acid–dichromic acid solution

Abstract

The sulfuric acid leaching process is regarded as a promising, cleaner method to prepare trivalent chromium products from chromite; however, the decomposition mechanism of the ore is poorly understood. In this work, binary spinels of Mg–Al, Mg–Fe, and Mg–Cr in the powdered and lump states were synthesized and used as raw materials to investigate the decomposition mechanism of chromite in sulfuric acid–dichromic acid solution. The leaching yields of metallic elements and the changes in morphology of the spinel were studied. The experimental results showed that the three spinels were stable in sulfuric acid solution and that dichromic acid had little influence on the decomposition behavior of the Mg–Al spinel and Mg–Fe spinel because Mg²⁺, Al³⁺, and Fe³⁺ in spinels cannot be oxidized by Cr6+. However, in the case of the Mg–Cr spinel, dichromic acid substantially promoted the decomposition efficiency and functioned as a catalyst. The decomposition mechanism of chromite in sulfuric acid–dichromic acid solution was illustrated on the basis of the findings of this study.

Keywords

hydrometallurgy / chromite / sulfuric acid leaching / spinel / decomposition mechanism

References

[1] Chen M., Shu J.F., Mao H.K., Xie X.D., Hemley R.J. Natural occurrence and synthesis of two new postspinel polymorphs of chromite. PNAS, 2003, 100(25): 14651.

[2] Yarkadaş G., Yildiz K. Effects of mechanical activation on the soda roasting of chromite. Can. Metall. Q., 2009, 48(1): 69.

[3] Hussein M.K., Kolta G.A., Abdel Aal O. Extraction of chromium from Egyptian chromite ores. Can. Metall. Q., 1972, 11(3): 481.

[4] Zhang M.X., Jiang C.L., Wei S.A., Tan S.Y., Dong L.C. Solubility equilibrium of the NaOH–H₂O–Na₂CrO₄–Na₂SiO₃–NaAlO₂ multicomponent systems involved in the liquid-phase oxidation of chromite. Ind. Eng. Chem. Res., 2014, 53(47): 18311.

[5] Chen G., Wang J.J., Wang X.H., Zheng S.L., Du H., Zhang Y. An investigation on the kinetics of chromium dissolution from Philippine chromite ore at high oxygen pressure in KOH sub-molten salt solution. Hydrometallurgy, 2013, 139, 46.

[6] Qi T.G., Liu N., Li X.B., Peng Z.H., Liu G.H., Zhou Q.S. Thermodynamics of chromite ore oxidative roasting process. J. Cent. South Univ. Technol., 2011, 18(1): 83.

[7] Sampath S., Sali S.K., Jayadevan N.C. Thermochemical studies in the sodium–chromium–oxygen system. Thermochim. Acta, 1990, 159, 327.

[8] Jagupilla S.C., Wazne M., Moon D.H. Assessment of ferrous chloride and Portland cement for the remediation of chromite ore processing residue. Chemosphere, 2015, 136, 95.

[9] Dey S., Paul A.K. Evaluation of chromate reductase activity in the cell-free culture filtrate of Arthrobacter sp. SUK 1201 isolated from chromite mine overburden. Chemosphere, 2016, 156, 69.

[10] S.B. Wilbur, H. Abadin, M. Fay, D. Yu, B. Tencza, L. Ingerman, J. Klotzbach, and S. James, Toxicological Profile for Chromium, Agency for Toxic Substances and Disease Registry, Atlanta, p. 155.

[11] Senol A. Amine extraction of chromium(VI) from aqueous acidic solutions. Sep. Purif. Technol., 2004, 36(1): 63.

[12] Geveci A., Topkaya Y., Ayhan E. Sulfuric acid leaching of Turkish chromite concentrate. Miner. Eng., 2002, 15(11): 885.

[13] Liu C.J., Qi J., Jiang M.F. Experimental study on sulfuric acid leaching behavior of chromite with different temperature. Adv. Mater. Res., 2011, 361-363(1): 628.

[14] Zhao Q., Liu C.J., Shi P.Y., Zhang B., Jiang M.F., Zhang Q.S., Zevenhoven R., Saxén H. Sulfuric acid leaching kinetics of South African chromite. Int. J. Miner. Metall. Mater., 2015, 22(3): 233.

[15] Liu K., Chen Q.Y., Hu H.P. Comparative leaching of minerals by sulphuric acid in a Chinese ferruginous nickel laterite ore. Hydrometallurgy, 2009, 98(3-4): 281.

[16] Zhao Q., Liu C.J., Yang D.P., Shi P.Y., Jiang M.F., Li B.K., Saxén H., Zevenhoven R. A cleaner method for preparation of chromium oxide from chromite. Process Saf. Environ. Prot., 2017, 105, 91.

[17] Li X.B., Xu W.B., Zhou Q.S., Peng Z.H., Liu G.H. Leaching kinetics of acid-soluble Cr(VI) from chromite ore processing residue with hydrofluoric acid. J. Cent. South Univ. Technol., 2011, 18(2): 399.

[18] Das G.K., Acharya S., Anand S., Das R.P. Acid pressure leaching of nickel-containing chromite overburden in the presence of additives. Hydrometallurgy, 1995, 39(1-3): 117.

[19] Das G.K., Anand S., Acharya S., Das R.P. Characterisation and acid pressure leaching of various nickel-bearing chromite overburden samples. Hydrometallurgy, 1997, 44(1-2): 97.

[20] Liu C.J., Sun L.F., Shi P.Y., Jiang M.F. Study on sulphuric acid leaching technology from chromite. J. Ecotechnol. Res., 2006, 12(3): 177.

[21] Biermann W.J., Heinrichs M. The attack of chromite by sulfuric acid. Can. J. Chem., 1960, 38, 1449.

[22] Vardar E., Eric R.H., Letowski F.K. Acid leaching of chromite. Miner. Eng., 1994, 7(5-6): 605.

[23] Jiang M.F., Zhao Q., Liu C.J., Shi P.Y., Zhang B., Zhang Q.S., Saxén H., Zevenhoven R. Sulfuric acid leaching of South African chromite. Part 2: Optimization of leaching conditions. Int. J. Miner. Process., 2014, 130, 102.

[24] Zhao Q., Liu C.J., Shi P.Y., Zhang B., Jiang M.F., Zhang Q.S., Saxén H., Zevenhoven R. Sulfuric acid leaching of South African chromite. Part 1: Study on leaching behavior. Int. J. Miner. Process., 2014, 130, 95.

[25] Samada Y., Miki T., Hino M. Prevention of chromium elution from stainless steel slag into seawater. ISIJ Int., 2011, 51(5): 728.

[26] G.D. Zhou, X.Z. Ye, and N.Z. Wu, Chemical Elements Survey, Science Press, Beijing, p. 166.