Decomposition behaviour of chromite in the HCl-HF system

doi:10.11949/0438-1157.20221479

Abstract

Abstract:

The production of chromium salt by acid leaching and decomposition of chromite shows a great application prospect because the process can avoid the production of hexavalent chromium [Cr(‍Ⅵ)]. Using hydrochloric acid as the acid-leaching agent can take advantage of the difference in solubility of metal ions in hydrochloric acid, making the process characterized by easy recovery of residual acid and chromium salts. However, it also makes the leaching efficiency of chromite leaching by hydrochloric acid low because of the dissolution equilibrium. In this paper, a new process study of hydrofluoric acid (HF) enhanced chromite leaching by hydrochloric acid is proposed to improve the chromite leaching process’s efficiency. Based on the previous work, this paper investigates the laws, kinetics, and process mechanism of HF-enhanced chromite hydrochloric acid leaching. The results show that HF can significantly enhance the leaching rate of Cr and Fe in chromite, which increases with the increase of HF dosage, while the leaching rate of Al and Mg shows a trend of increasing and then decreasing with the rise of HF dosage. The other crystalline silicates enter the slag phase. This finding provides a basis for selecting appropriate leaching conditions to better separate Cr from impurities such as Al and Mg in the leachate. Cr, Fe, Al and Mg leaching rates can reach about 92%, 94%, 17%, and 14%, respectively, at higher HF dosages. HF dosage not only influences the control steps of the kinetics of the chromite hydrochloric acid leaching process but also plays an essential role in promoting the conversion of Al, Mg and Si-containing substances in the leachate to crystalline silicates.

Key words: chromite, acid leaching process, hydrofluoric acid, process intensification

摘要：

铬铁矿酸浸分解制铬盐因其过程可以避免危险性物质六价铬[Cr(Ⅵ)]的产生而显示出较大应用前景，以盐酸为酸浸剂可以利用金属离子在盐酸中溶解度的差异，使工艺具有易于回收剩余酸和铬盐的特点。但是，也因为溶解平衡，使盐酸浸出铬铁矿的浸出效率较低，为了提高铬铁矿盐酸浸出过程的效率，提出了氢氟酸(HF)强化铬铁矿盐酸浸出的新工艺。在前期工作基础上，研究了HF强化铬铁矿盐酸浸出的规律、动力学及过程机理。结果表明，HF可以大大强化铬铁矿中Cr、Fe的浸出速率，且随HF用量增加而增大；而其中Al、Mg的浸出速率随HF用量的增加呈现先增加后减小的趋势，其主要原因是HF用量大时可以促进体系中含Al、Mg、Si物质形成Mg₂SiO₄、(Mg, ‍Al)SiO₃、Al₂SiO₅等结晶性硅酸盐，进入渣相中。这一发现为选择适当的浸出条件，实现浸出液中Cr与Al、Mg等杂质的更好分离提供了依据。在较高HF用量下，Cr、Fe、Al、Mg的浸出率可分别达到约92%、94%、17%、14%。HF的用量不仅影响铬铁矿盐酸浸出过程动力学的控制步骤，在促进浸出液中含Al、Mg、Si物质转化生成结晶性硅酸盐方面也起着重要的作用。

关键词: 铬铁矿, 酸浸, 氢氟酸, 过程强化

CLC Number:

TF 803.21

Hao CHEN, Yijuan TIAN, Xuejun QUAN, Ziwen JIANG, Gang LI. Decomposition behaviour of chromite in the HCl-HF system[J]. CIESC Journal, 2023, 74(3): 1161-1174.

陈号, 田仪娟, 全学军, 蒋子文, 李纲. 铬铁矿在HCl-HF体系中的分解行为[J]. 化工学报, 2023, 74(3): 1161-1174.

Figures/Tables 17

Fig.1 Experimental setup for the acid leaching of chromite

Table 1 Main chemical composition of chromite from South Africa

元素	含量/(mg/g)
Cr	293.79
Fe	181.96
Al	76.20
Mg	52.36
Si	16.40

Fig.2 XRD patterns of chromite from South Africa

Fig.3 SEM image of chromite from South Africa

Fig.4 Particle size distribution curve of chromite ore

Fig.5 Effect of HF dosage on the leaching rate of metals

Fig.6 XRD patterns of chromium residue at different HF dosage

Fig.7 Variation of leaching rate of major metal ions with time at different temperatures when HF dosage is 3 times the theoretical amount

Fig.8 Variation of leaching rate of major metal ions with time at different temperatures when HF dosage is 10 times the theoretical amount

Fig.9 XRD patterns of chromium residue at different leaching time when HF dosage is 3 times the theoretical amount

Fig.10 XRD patterns of chromium residue at different leaching time when HF dosage is 10 times the theoretical amount

Fig.11 SEM images of chromium residue at different leaching time when HF dosage is 3 times the theoretical amount

Fig.12 SEM images of chromium residue at different leaching time when HF dosage is 10 times the theoretical amount

Fig.13 Fitted curves for the leaching kinetic of the metals at different temperatures when HF dosage is 3 times theoretical amout

Table 2 Variation of the reaction rate constant with temperature for each metal in the leaching process when HF dosage is 3 times theoretical amount

Temperature/℃	固体产物层扩散控制				界面化学反应控制
Temperature/℃	k_i(Cr)/min^-1	k_i(Fe)/min^-1	k_i(Al)/min^-1	k_i(Mg)/min^-1	k_r(Cr)/min^-1	k_r(Fe)/min^-1	k_r(Al)/min^-1	k_r(Mg)/min^-1
100	2.46051×10^-6	9.19429×10^-6	5.27136×10^-6	1.56694×10^-6	5.44832×10^-5	1.06872×10^-4	5.76641×10^-5	4.38630×10^-5
120	1.73265×10^-5	3.41549×10^-5	3.57455×10^-5	4.22081×10^-6	1.44503×10^-4	2.06567×10^-4	1.39782×10^-4	7.21222×10^-5
140	9.50439×10^-5	1.53615×10^-4	1.65633×10^-4	1.77324×10^-5	3.45840×10^-4	4.47295×10^-4	2.94154×10^-4	1.42844×10^-4
160	2.55933×10^-4	3.57935×10^-4	4.91442×10^-4	8.11095×10^-5	5.93726×10^-4	5.55457×10^-4	5.06541×10^-4	3.15485×10^-4
180	5.38569×10^-4	7.36588×10^-4	9.23902×10^-4	2.46691×10^-4	8.93989×10^-4	1.06979×10^-3	7.47020×10^-4	5.66920×10^-4
200	1.06968×10^-3	1.37972×10^-3	1.4200×10^-3	7.58054×10^-4	1.32973×10^-3	1.54000×10^-3	9.83350×10^-4	8.39131×10^-4

Fig.14 Arrhenius plots for the leaching reactions of the metal elements in the chromite

Fig.15 Fitted curves for the leaching kinetic of the metals at different temperatures when HF dosage is 10 times theoretical amount

References 32

1	Sanchez-Segado S, Jha A. Physical chemistry of roasting and leaching reactions for chromium chemical manufacturing and its impact on environment—a review[M]//Materials Processing Fundamentals. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2013: 225-236.
2	Xu H B, Zheng S L, Zhang Y, et al. Oxidative leaching of a Vietnamese chromite ore in highly concentrated potassium hydroxide aqueous solution at 300℃ and atmospheric pressure[J]. Minerals Engineering, 2005, 18(5): 527-535.
3	Antony M P, Jha A, Tathavadkar V. Alkali roasting of Indian chromite ores: thermodynamic and kinetic considerations[J]. Mineral Processing and Extractive Metallurgy, 2006, 115(2): 71-79.
4	Liu Z B, Zheng J Y, Liu W Z, et al. Identification of the key host phases of Cr in fresh chromite ore processing residue (COPR)[J]. Science of the Total Environment, 2020, 703: 135075.
5	Zhang X R, Li G, Wu J, et al. Leaching of valuable elements from the waste chromite ore processing residue: a kinetic analysis[J]. ACS Omega, 2020, 5(31): 19633-19638.
6	Zhang Y, Li Z H, Qi T, et al. Green manufacturing process of chromium compounds[J]. Environmental Progress, 2005, 24(1): 44-50.
7	陈宁, 董明甫, 黄玉西, 等. 铬盐产业绿色发展现状及展望[J]. 无机盐工业, 2018, 50(10): 10-13.
	Chen N, Dong M F, Huang Y X, et al. Current status and prospect of green development of chromium salts industry[J]. Inorganic Chemicals Industry, 2018, 50(10): 10-13.
8	封承飞, 曾奎, 田仪娟, 等. 铬铁矿液相氧化浸出及动力学研究[J]. 湿法冶金, 2022, 41(3): 205-212.
	Feng C F, Zeng K, Tian Y J, et al. Pressure oxidative leaching and leaching kinetics of chromite[J]. Hydrometallurgy of China, 2022, 41(3): 205-212.
9	Zhang Y, Li Z H, Qi T, et al. Green chemistry of chromate cleaner production[J]. Chinese Journal of Chemistry, 1999, 17(3): 258-266.
10	张懿, 李佐虎, 王志宽, 等. 铬酸钠的清洁生产方法: 1226512[P]. 1999-08-25.
	Zhang Y, Li Z H, Wang Z K, et al. Method for cleaner production of sodium vanadate and sodium chromate by pressure leaching of vanadium slag: 1226512[P]. 1999-08-25.
11	中国科学院过程工程研究所. 铬盐清洁生产技术实现万吨规模生产: 万吨级铬盐清洁生产技术优化集成与标志性工程建设[J]. 中国科学院院刊, 2007, 22(5): 423-424.
	Institute of Process Engineering, Chinese Academy of Sciences. Cleaner production technology of chromium salt realizes 10,000-ton scale production—optimization and integration of cleaner production technology of 10,000-ton chromium salt and landmark project construction[J]. Bulletin of Chinese Academy of Sciences, 2007, 22(5): 423-424.
12	Zhang B, Shi P Y, Jiang M F. Advances towards a clean hydrometallurgical process for chromite[J]. Minerals, 2016, 6(1): 7.
13	Vardar E, Eric R H, Letowski F K. Acid leaching of chromite[J]. Minerals Engineering, 1994, 7(5/6): 605-617.
14	Zhao Q, Liu C J, Shi P Y, et al. Cleaner production of chromium oxide from low Fe(Ⅱ)-chromite[J]. Minerals, 2020, 10(5): 460.
15	Zhao Q, Liu C J, Li B K, et al. Decomposition mechanism of chromite in sulfuric acid-dichromic acid solution[J]. International Journal of Minerals, Metallurgy, and Materials, 2017, 24(12): 1361-1369.
16	Shi P Y, Liu C J, Zhao Q, et al. Study on mechanisms of different sulfuric acid leaching technologies of chromite[J]. International Journal of Minerals, Metallurgy, and Materials, 2017, 24(9): 983-990.
17	Liu C J, Qi J, Jiang M F. Experimental study on sulfuric acid leaching behavior of chromite with different temperature[J]. Advanced Materials Research, 2011, 361/362/363: 628-631.
18	Geveci A, Topkaya Y, Ayhan E. Sulfuric acid leaching of Turkish chromite concentrate[J]. Minerals Engineering, 2002, 15(11): 885-888.
19	Zhao Q, Liu C J, Yang D P, et al. A cleaner method for preparation of chromium oxide from chromite[J]. Process Safety and Environmental Protection, 2017, 105: 91-100.
20	Amer M A. Processing of Ras-Shait chromite deposits[J]. Hydrometallurgy, 1992, 28(1): 29-43.
21	Biermann W J, Heinrichs M. The attack of chromite by sulphuric acid [J]. Canadian Journal of Chemistry, 1960, 38(9): 1449-1454.
22	Jiang M F, Zhao Q, Liu C J, et al. Sulfuric acid leaching of South African chromite. Part 2: Optimization of leaching conditions[J]. International Journal of Mineral Processing, 2014, 130: 102-107.
23	Zhao Q, Liu C J, Shi P Y, et al. Sulfuric acid leaching of South African chromite. Part 1: Study on leaching behavior[J]. International Journal of Mineral Processing, 2014, 130: 95-101.
24	Lai H X, Huang L Q, Gan C H, et al. Enhanced acid leaching of metallurgical grade silicon in hydrofluoric acid containing hydrogen peroxide as oxidizing agent[J]. Hydrometallurgy, 2016, 164: 103-110.
25	Koohestani B, Darban A K, Mokhtari P, et al. Influence of hydrofluoric acid leaching and roasting on mineralogical phase transformation of pyrite in sulfidic mine tailings[J]. Minerals, 2020, 10(6): 513.
26	Li X B, Xu W B, Zhou Q S, et al. Leaching kinetics of acid-soluble Cr(‍Ⅵ) from chromite ore processing residue with hydrofluoric acid[J]. Journal of Central South University, 2011, 18(2): 399-405.
27	李密, 黄婧, 戴士祥, 等. 采用HF和HClO₄从铀尾矿中浸出铀的试验研究[J]. 中国矿业大学学报, 2016, 45(3): 639-645.
	Li M, Huang J, Dai S X, et al. Extraction of uranium from uranium tailings by acid leaching with HF and HClO₄ [J]. Journal of China University of Mining & Technology, 2016, 45(3): 639-645.
28	Guo H, Yu H Z, Zhou A A, et al. Kinetics of leaching lithium from α‍-spodumene in enhanced acid treatment using HF/H₂SO₄ as medium[J]. Transactions of Nonferrous Metals Society of China, 2019, 29(2): 407-415.
29	Guo H, Kuang G, Li H, et al. Enhanced lithium leaching from lepidolite in continuous tubular reactor using H₂SO₄+H₂SiF₆ as lixiviant[J]. Transactions of Nonferrous Metals Society of China, 2021, 31(7): 2165-2173.
30	Philip K G, Charles Q J. Critical evaluation of coupling particle size distribution with the shrinking core model[J]. Chemical Engineering Science, 2004, 59(10): 1979-1987.
31	Li Y B, Kawashima N, Li J, et al. A review of the structure, and fundamental mechanisms and kinetics of the leaching of chalcopyrite[J]. Advances in Colloid and Interface Science, 2013, 197/198: 1-32.
32	An J, Yang W Q, Yin J G, et al. Kinetics of phosphorus removal from high-phosphorus iron ores by HCl leaching[J]. Advanced Materials Research, 2013, 868: 455-458.

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