Wet synthesis of high-density basic cobalt carbonate powder and thermodynamic analysis of Co(Ⅱ)-NH3-CO32--H2O system
XU Wei1, XIA Jie1,2, ZHANG Kejun1, HU Bin1, BAI Dehong1, HE Kai1, YUAN Tiechui2, LI Ruidi2
1. Quzhou Huayou Cobalt New Material Co., Ltd., Quzhou 324000, China; 2. Powder Metallurgy Research Institute, Central South University, Changsha 410083, China
Abstract：CoCl2 and four kinds of precipitants commonly used in industry, namely (NH4)2CO3, NH4HCO3, Na2CO3 and NaHCO3, were used as raw materials to prepare basic cobalt carbonate by wet synthesis. The as-prepared basic cobalt carbonate were studied by means of lazer particle analyzer, scanning electron microscope, X-ray diffractometer and vibrating densitometer. The effects of solution pH value and NH3 concentration on particle size, microscopic morphology, crystal structure and density of basic cobalt carbonate powder were evaluated, and the thermodynamic analysis of Co(II)-NH3-CO32--H2O system was performed as well. The results show that the pH value and NH3 concentration of the solution have a great influence on the complexation and precipitation behavior of cobalt ions. Based on the complexing precipitation process, the tap density of the basic cobalt carbonate solid powders prepared with NH4HCO3 and (NH4)2CO3 precipitant is higher. Based on the principle of simultaneous equilibrium and mass conservation, the thermodynamic diagram of lg[Co]total on pH under different solution compositions was drawn, and the effect of solution pH value of different systems on the precipitation process was further studied. The results show that the precipitation rate of cobalt ions is more than 90% when the pH is 6-8. In the Na2CO3 and NaHCO3 precipitant systems, free Co2+ is dominant during the transient, and it precipitates rapidly after contacting the precipitant to form loose flocculated basic cobalt carbonate powders. In the (NH4)2CO3 and NH4HCO3 precipitant systems, Co2+ is coordinated with ammonia, the precipitation process procees slowly with the release of Co2+ from multi coordinated Co(NH3)n2+ (n=1, 2,…, 6), results in dense powders.
[1] LÜ X W, LIU Y, HAO R, et al.Urchin-like Al-doped Co3O4 nanospheres rich in surface oxygen vacancies enable efficient ammonia electrosynthesis[J]. ACS Applied Materials & Interfaces, 2020, 12(15): 17502-17508. [2] ZHAO S, WEI Z.Shape-controlled Co3O4 as advanced electrode materials for high-performance supercapacitor[J]. International Journal of Electrochemical Science, 2019, 14(7): 6276-6282. [3] PARK J S, CHO J S, KIM J H, et al.Electrochemical properties of micron-sized Co3O4 hollow powders consisting of size controlled hollow nanospheres[J]. Journal of Alloys and Compounds, 2016, 689(12): 554-563. [4] 胡雷, 刘志宏. 四氧化三钴粉末的制备与应用现状[J]. 粉末冶金材料科学与工程, 2008, 13(4): 195-200. HU Lei, LIU Zhihong.Preparation and application of Co3O4 powder[J]. Materials Science and Engineering of Powder Metallurgy, 2008, 13(4): 195-200. [5] ARDIZZONE S, SPINOLO G, TRASATTI S.The point of zero charge of Co3O4 prepared by thermal decomposition of basic cobalt carbonate[J]. Electrochimica Acta, 1995, 40(16): 2683-2686. [6] 李艳, 林晨光, 曹瑞军. 超细晶WC-Co硬质合金用纳米钴粉的研究现状与展望[J]. 稀有金属, 2011, 35(3): 451-457. LI Yan, LIN Chenguang, CAO Ruijun.Research status and prospect of nanometer cobalt powder for ultrafine WC-Co hard alloys[J]. Chinese Journal of Rare Metals, 2011, 35(3): 451-457. [7] 宇文超, 刘秉国, 彭金辉, 等. 响应曲面法优化碱式碳酸钴煅烧制备Co3O4工艺研究[J]. 矿冶工程, 2021, 41(1): 114-118. YU Wenchao, LIU Bingguo, PENG Jinhui, et al.Optimization of calcination with basic cobalt carbonate for preparation of Co3O4 by response surface methodology[J]. Mining and Metallurgical Engineering, 2021, 41(1): 114-118. [8] 黄草明, 教光辉, 肖发新, 等. 沉淀法制备微米四氧化三钴试验研究[J]. 湿法冶金, 2019, 38(3): 243-248. HUANG Caoming, JIAO Guanghui, XIAO Faxin, et al.Preparation of micron cobaltosic oxide by precipitation method[J]. Hydrometallurgy of China, 2019, 38(3): 243-248. [9] 刘人生, 王丽平, 秦鸣飞, 等. 液相沉淀-煅烧法制备大粒径球形四氧化三钴[J]. 精细化工, 2019, 36(2): 206-211. LIU Rensheng, WANG Liping, QIN Mingfei, et al.Synthesis of spherical Co3O4 with large-size via liquid phase precipitation- calcination method[J]. Fine Chemicals, 2019, 36(2): 206-211. [10] 王崇国, 陈卫东. 超细球形钴粉制备[J]. 有色金属工程, 2014, 4(6): 18-20. WANG Chongguo, CHEN Weidong.Preparation of ultrafine spherical cobalt powder[J]. Nonferrous Metals Engineering, 2014, 4(6): 18-20. [11] HE L H, ZHAO Z W, LIU X H, et al.Thermodynamics analysis of LiFePO4 precipitation from Li-Fe(II)-P-H2O system at 298 K[J]. Transactions of Nonferrous Metals Society of China, 2012, 22(7): 1766-1770. [12] YAO Y L, ZHANG C F, ZHAN J, et al.Thermodynamics analysis of Ni2+-C2H8N2-C2O42--H2O system and preparation of Ni microfiber[J]. Transactions of Nonferrous Metals Society of China, 2013, 23(11): 3456-3461. [13] LI Y J, LI L, SU Q Y, et al.Thermodynamic analysis of Li-Ni-Co-Mn-H2O system and synthesis of LiNi0.5Co0.2Mn0.3O2 composite oxide via aqueous process[J]. Journal of Central South University, 2019, 26(10): 2668-2680. [14] 苏继桃, 苏玉长, 赖智广, 等. 共沉淀法制备镍、钴、锰复合碳酸盐的热力学分析[J]. 硅酸盐学报, 2006, 34(6): 695-698. SU Jitao, SU Yuchang, LAI Zhiguang, et al.Thermodynamic analysis of preparation of multiple carbonate of Ni, Co and Mn by coprecipitation method[J]. Journal of the Chinese Ceramic Society, 2006, 34(6): 695-698. [15] 李洪桂, 郑清远, 张启修, 等. 湿法冶金学[M]. 长沙: 中南大学出版社, 2002: 362-364. LI Honggui, ZHENG Qingyuan, ZHANG Qixiu, et al.Hydrometallurgy[M]. Changsha: Central South University Press, 2002: 362-364. [16] GUO X Y, HUANG K, ZHANG D M.Preparation of basic nickel carbonate particles in solution system of Ni(Ⅱ)-NH3-CO32--H2O[J]. Transactions of Nonferrous Metals Society of China, 2004, 14(5): 1006-1011. [17] 彭忠东, 杨建红, 邹忠, 等. 共沉淀法制备掺杂氧化锌压敏陶瓷粉料热力学分析[J]. 无机材料学报, 1999, 14(5): 733-738. PENG Zhongdong, YANG Jianhong, ZOU Zhong, et al.Thermodynamic analysis of doped zinc oxide varistor ceramic powders by coprecipitation process[J]. Journal of Inorganic Materials, 1999, 14(5): 733-738. [18] 傅崇说. 有色冶金应用基础研究[M]. 北京: 科学出版社, 1993: 18-20. FU Chongyue.Fundamental Research on Nonferrous Metallurgy Application[M]. Beijing: Science Press, 1993: 18-20. [19] 李庆扬. 数值分析[M]. 北京: 清华大学出版社, 2008: 222-228. LI Qingyang.Numerical Analysis[M]. Beijing: Tsinghua University Press, 2008: 222-228.
2022, Vol. 27 
