Understanding the leaching behavior of calcium molybdate through the construction of lgc—pH diagrams

Abstract

CaMoO₄ is not only the main component of powellite, but also a key intermediate product in molybdenum metallurgy. The current leaching of CaMoO₄ is mainly in experimental and industrial research, and seldom in theoretical analysis. In this research, lgc - pH diagrams for Ca-Mo-H₂O, Ca-Mo-PO₄-H₂O, Ca-Mo-SiO₄-H₂O, Ca-Mo-CO₃-H₂O, Ca-Mo-Y(EDTA)-H₂O, and Ca-Mo-F-H₂O systems were constructed to predict the dissolution behavior of CaMoO₄ in Na₂EDTA, Na₂SiO₃, Na₃PO₄, Na₂CO₃, and NaF solutions. The diagrams suggest that CaMoO₄ can be dissolved by the five types of solutions and the solid products, for example, Ca₅(PO₄)₃OH, CaSiO₃, Ca₃Si₂O₇, CaCO₃ and CaF₂ were generated depending on the added reagent, while calcium combines with EDTA to form soluble CaY²⁻ in Na₂EDTA solution. The stability regions of CaMoO₄ and solid products are dependent on the ion concentration and pH value. Meanwhile, the proper increase of reagent concentration and pH is beneficial for raising the solubility of molybdenum. The leaching experiments of synthetic CaMoO₄ in various media indicate that CaMoO₄ can be dissolved with a high leaching efficiency which was in accord with the thermodynamic analysis. This work presents the construction of thermodynamic diagrams that is useful in the analysis of the encountered phenomena in molybdenum hydrometallurgy and provides a thermodynamic approach for treating CaMoO₄.

Keywords

thermodynamic / CaMoO₄ / leaching / lgc-pH diagrams

References

[1] LasheenT A, El-AhmadyM E, HassibH B, et al. . Molybdenum metallurgy review: Hydrometallurgical routes to recovery of molybdenum from ores and mineral raw materials [J]. Mineral Processing and Extractive Metallurgy Review, 2015, 36(3): 145-173

[2] LYU Ying, LI Hong-gui. Utilize tungsten concentrates of high molybdenum rationally [J]. China Tungsten Industry, 2005(5): 15–16, 21. (in Chinese)

[3] LiH. Production of high purity APT from scheelite and complex tungsten raw materials with a high Mo content [J]. Transactions of Nonferrous Metals Society of China, 2004, 14(2): 366-369

[4] LiY, YangJ, ZhaoZ. Recovery of tungsten and molybdenum from low-grade scheelite [J]. JOM, 2017, 69(10): 1958-1962

[5] ZhangW, WangC, MaB. Leaching kinetics of calcium molybdate with hydrochloric acid in presence of phosphoric acid [J]. Transactions of Nonferrous Metals Society of China, 2019, 29(4): 859-867

[6] LiuD, YangL, DengX, et al. . Re-Os isotopic data for molybdenum from Hejiangkou tungsten and tin polymetallic deposit in Chenzhou and its geological significance [J]. Journal of Central South University, 2016, 23(5): 1071-1084

[7] SinghS, ChettyM K, JunejaJ M, et al. . Studies on the processing of a low grade molybdenite concentrate by lime roasting [J]. Minerals Engineering, 1988, 1(4): 337-342

[8] JunejaJ M, SinghS, BoseD K. Investigations on the extraction of molybdenum and rhenium values from low grade molybdenite concentrate [J]. Hydrometallurgy, 1996, 41(2–3): 201-209

[9] WangM, WangX, LiuW. A novel technology of molybdenum extraction from low grade Ni-Mo ore [J]. Hydrometallurgy, 2009, 97(1–2): 126-130

[10] BhappuR B, ReynoldsD H, RomanR J. Molybdenum recovery from sulfide and oxide ores [J]. JOM, 1965, 17(11): 1199-1205

[11] JiangK, WangY, ZouX, et al. . Extraction of molybdenum from molybdenite concentrates with hydrometallurgical processing [J]. JOM, 2012, 64(11): 1285-1289

[12] ZhangQ, ZhaoQTungsten and molybdenum metallurgy [M], 2007, Beijing, Metallurgical Industry Press: 96(in Chinese)

[13] DOUGLAS D A, MENASHI J, RAPPAS A S. Process for recovering chromium, vanadium, molybdenum and tungsten values from a feed material: US4298581 [P]. 1981-11-03.

[14] LinL, LiuK, ShibayamaA, et al. . Recovery of tungsten and vanadium from tungsten alloy scrap [J]. Hydrometallurgy, 2004, 72(1–2): 1-8

[15] LiZ, ChuY. A literature review of the recovery of molybdenum and vanadium from spent hydrodesulphurisation catalysts, Part II: Separation and purification [J]. Hydrometallurgy, 2009, 98(1–2): 10-20

[16] SwinkelsP L J, van der WeijdenR D, AjahA N, et al. . Conceptual process design as a prerequisite for solving environmental problems: A case study of molybdenum removal and recovery from wastewater [J]. Minerals Engineering, 2004, 17(2): 205-215

[17] WangM, WeiC, FanG, et al. . Molybdenum recovery from oxygen pressure water leaching residue of Ni - Mo ore [J]. Rare Metals, 2013, 32(2): 208-212

[18] NguyenT H, LeeM S. Development of a hydrometallurgical process for the recovery of calcium molybdate and cobalt oxalate powders from spent hydrodesulphurization (HDS) catalyst [J]. Journal of Cleaner Production, 2015, 90: 388-396

[19] IlhanS, KalpakliA O, KahrumanC, et al. . The use of Langmuir-Hinshelwood mechanism to explain the kinetics of calcium molybdate leaching in oxalic acid solution [J]. Hydrometallurgy, 2012, 127–128: 91-98

[20] ZhangW, LiJ, ZhaoZ, et al. . Recovery and separation of W and Mo from high-molybdenum synthetic scheelite in HCl solutions containing H₂O₂ [J]. Hydrometallurgy, 2015, 155: 1-5

[21] PanM, ZhuY. Experimental study on leaching molybdenum at high-pressure from calcium molybdate [J]. China Molybdenum Industry, 2005, 29(6): 19-21(in Chinese)

[22] ZhangW, YangJ, ZhaoZ, et al. . Coordination leaching of tungsten from scheelite concentrate with phosphorus in nitric acid [J]. Journal of Central South University, 2016, 23(6): 1312-1317

[23] ZhangW, WangC, MaB. Leaching kinetics of calcium molybdate with hydrochloric acid in presence of phosphoric acid [J]. Transactions of Nonferrous Metals Society of China, 2019, 29(4): 859-867

[24] ZhangD, YangT, LiuW, et al. . Pressure leaching of bismuth sulfide concentrate containing molybdenum and tungsten in alkaline solution [J]. Journal of Central South University, 2012, 19(12): 3390-3395

[25] ZhaoZ, LiJ, WangS, et al. . Extracting tungsten from scheelite concentrate with caustic soda by autoclaving process [J]. Hydrometallurgy, 2011, 108(1–2): 152-156

[26] MartinsJ P. Kinetics of soda ash leaching of low-grade scheelite concentrates [J]. Hydrometallurgy, 1996, 42(2): 221-236

[27] KonishiY, KatadaH, AsaiS. Leaching kinetics of tungsten from low-grade scheelite ore in aqueous Na₄EDTA solutions [J]. Hydrometallurgy, 1990, 23(2–3): 141-152

[28] YangJ, HeL, LiuX, et al. . Comparative kinetic analysis of conventional and ultrasound-assisted leaching of scheelite by sodium carbonate [J]. Transactions of Nonferrous Metals Society of China, 2018, 28(4): 775-782

[29] Osseo-AsareK. Solution chemistry of tungsten leaching systems [J]. Metallurgical Transactions B, 1982, 13(4): 555-564

[30] SpeightJ GLange’s handbook of chemistry [M], 200516th EditionNew York, McGraw-Hill

[31] CasassasE. Handbook of chemical equilibria in analytical chemistry [J]. TrAC Trends in Analytical Chemistry, 1985, 4(10): 20-21

[32] ChughtaiA, MarshallR, NancollasG H. Complexes in calcium phosphate solutions [J]. The Journal of Physical Chemistry, 1968, 72(1): 208-211

[33] ZhaoZTheory and application of tungsten metallurgy [M], 2013, Beijing, Tsinghua University Press: 7780(in Chinese)

[34] LiH, YinG, SunP, et al. Behabiviours of accompanying molybdenum and tin minerals in the alkaline decomposition of tungsten concentrate [M], 1997, Changsha, Central South University Press: 72(in Chinese)