锌灰资源化回收及超临界水热合成纳米氧化锌系统工艺

Zinc Ash Recycling and the System of Supercritical Hydrothermal Synthesis of Nano-Zinc Oxide

为了对锌灰进行资源化回收及对其经济性进行分析,将湿法回收工艺和超临界水热合成技术相结合,将锌灰生成价值较高的纳米氧化锌产品,采用Aspen Plus软件平台,建立了完整的系统工艺,并分析了系统运行过程中的物料成本及能耗成本。在硫酸浓度为2 mol·L^(-1)、固液比为1∶8、浸出温度为50℃、浸出时间为2 h、搅拌器转速为300 r·min^(-1)的条件下,锌灰中锌的浸出率达到了95%以上。除杂过程除去了Fe、Al、Ni、Cu等杂质,除杂后的溶液中锌的质量分数达到了97%。利用锌灰浸出液在400℃和25 MPa的超临界条件下,合成了平均粒径为26 nm的纳米氧化锌,晶体结晶度良好,纯度较高。通过与纯物料所合成的纳米氧化锌进行对比,验证了该技术的可行性,显著提升了系统运行的经济性。

In this study,a combination of wet recovery process and supercritical hydrothermal synthesis technology is employed to produce high-value nano-zinc oxide products from zinc ash,and an economic analysis of this approach to zinc ash recycling is conducted.A sound system is established using Aspen Plus,and material costs and energy consumption during system operation are analyzed.The leaching rate of zinc in the zinc ash exceeds 95%,under the conditions of sulfuric acid concentration of 2 mol·L^(-1),solid-liquid ratio of 1∶8,leaching temperature of 50℃,leaching time of 2 h,and stirrer speed of 300 r·min^(-1).Fe,Al,Ni,Cu and other impurities are eliminated in the impurity removal process,and the zinc content in the solution after impurity removal reaches 97%.The leaching solution of zinc ash is used to synthesize nano-zinc oxide with an average particle size of 26 nm under supercritical conditions of 400℃and 25 MPa.The resulting zinc oxide exhibits excellent crystallinity and high purity.The comparison with nano-zinc oxide synthesized from pure materials validates the feasibility of this technology,which significantly improves the system’s economic viability.