【摘要】 系统研究了氯化钙（CaCl₂）、醋酸钙（（CH₃COO）₂Ca）和氧化钙（CaO）三种钙源在钒酸钠溶液钙化沉钒过程中对钒酸钙生成行为的影响。通过调控钒酸钠溶液pH与钙源添加量，考察了沉钒过程三种体系的pH变化规律、钒沉淀率、产物物相及微观形貌。结果表明，钒酸钠溶液pH与钙源添加量对沉钒反应前后pH和钒酸钙种类有较大影响。三种钙源在优化条件下均可实现99%以上的钒沉淀率，氯化钙和醋酸钙体系需要高pH和高钙源添加量，而氧化钙体系能主动构建并维持强碱性环境，因此在宽泛的pH范围内仅需控制高钙源添加量即可稳定实现高沉钒率。氯化钙与醋酸钙体系的钙化沉钒产物为焦钒酸钙Ca₂V₂O₇，而氧化钙体系生成多钒酸钙Ca₇V₄O₁₇。此外，不同钙源所得钒酸钙产物的形貌也有较大差异。更多还原

【Abstract】 This study systematically investigates and compares the influence of three distinct calcium sources—calcium chloride（CaCl₂）, calcium acetate（（CH₃ COO）₂ Ca）, and calcium oxide（CaO）— on the precipitation behavior and product characteristics during the formation of calcium vanadate from sodium vanadate solutions. The research focuses on the effects of varying the initial pH value of the sodium vanadate solution and the dosage of each calcium source on key process indicators, including pH evolution during precipitation, vanadium removal efficiency, phase composition of the solid products, and their microscopic morphology. The findings demonstrate that both the initial alkalinity of the solution and the amount of calcium added play critical roles in determining the pH trajectory of the reaction mixture as well as the polymorph of calcium vanadate produced. Under the optimal operational conditions, all three calcium sources achieve an exceptionally high vanadium precipitation efficiency exceeding 99%. However, the pathways to this high efficiency differ markedly. The calcium chloride and calcium acetate systems require a high initial pH and substantial stoichiometric excess of the calcium reagent to drive the precipitation to completion. In contrast, calcium oxide actively generate and maintain a highly alkaline environment in situ through its hydrolysis, thereby supporting effective vanadium removal across a broader pH range with careful control of dosage. Regarding the solid products, calcium chloride and calcium acetate primarily yields calcium pyrovanadate（Ca₂V₂O₇）, whereas calcium oxide favors the formation of calcium polyvanadate(Ca₇V₄O₁₇). These differences in phase formation suggest distinct precipitation mechanisms and equilibrium states governed by the solubility, ionic activity, and accompanying anions of each calcium source. Furthermore, the morphological features of the precipitates— such as crystal habit, particle size, and aggregation pattern— vary considerably depending on the calcium precursor used. These variations can be attributed to differences in nucleation kinetics, growth rates, and possible interactions between the precipitating species and the anions introduced by the calcium salts. The study provides valuable insights into the selection of calcium agents for vanadium recovery processes, highlighting the trade-offs between reagent cost, pH value control requirements, and product characteristics. Calcium oxide, for instance, offers the advantage of pH self-regulation and high efficiency over a wide operating window, which may simplify process control in industrial applications. On the other hand, calcium chloride and calcium acetate, while also effective, demand more stringent control of solution chemistry and may involve higher chemical consumption. Future work could explore the detailed nucleation and growth kinetics, the role of intermediate species, and the longterm stability and leaching behavior of the different calcium vanadate phases produced under varied conditions. Such investigations would further optimize the precipitation process for vanadium extraction and recovery, contributing to more sustainable and efficient hydrometallurgical practices.更多还原