液相沉淀-煅烧法制备大粒径球形四氧化三钴

Synthesis of Spherical Co_3O_4 with Large-size via Liquid Phase Precipitation-calcination Method

以硫酸钴为原料,碳酸氢铵为沉淀剂,采用液相沉淀法合成了大粒径球形碳酸钴,考察了不同晶种量、pH和硫酸钴溶液流量对碳酸钴形貌、粒度分布、振实密度和硫元素质量分数的影响,并探究了碳酸钴的生长机理。通过分步煅烧,并设置不同升温时间使碳酸钴热分解,得出优化四氧化三钴理化指标的煅烧条件。结果表明,当晶种量为2 kg,pH在7.2～7.5,硫酸钴溶液流量为500 mL/h时,采用分段式热分解碳酸钴,各温区按统一时间(60 min)升温,所得四氧化三钴形貌为球形,中值粒径为16.52μm,振实密度达2.26 g/cm3。

The spherical CoCO3 precursor was prepared by precipitation method using cobalt sulfate as cobalt source and ammonium bicarbonate as precipitating agent. The influences of dosage of seed crystal, pH value, and flow rate of cobalt sulfate solution on the morphology, particle size distribution, tap density and sulfur mass fraction of CoCO3 were investigated. Meanwhile, the growth mechanism of CoCO3 was studied. CoCO3 precursor was calcined at different heating-up time in order to optimize the physical and chemical properties of Co3O4. The results showed that the spherical Co3O4 with 16.52μm in median particle diameter and 2.26 g/cm^3 tap density could be obtained when the dosage of seed crystal was 2 kg, the pH value was 7.2-7.5, the flow rate of cobalt sulfate solution was 500 mL/h, and the thermal decomposition of precursor was carried out by staged heating, with 60 min heating-up time for each stage.