中文摘要：

为阐明砷在铅阳极泥碱性加压氧化浸出过程(NaNO3为氧化剂;NaOH为碱性试剂)中的热力学特性，通过热力学计算绘制体系离子质量浓度为0.1mol/kg，温度为298、373、423和473K条件下的As-Na-H2O、N-H2O和As-N-Na-H2O系的φ-pH图。结果表明，砷的存在形态与pH值有关。当pH值较低时，砷主要以H3AsO4、H2AsO4-、24HAsO-、H2AsO2-及As2O3的形式存在；当pH>11.14时，砷主要以3AsO4-形式存在，高碱浓度及高温对砷浸出有利。碱性加压氧化浸出实验表明，砷浸出率变化趋势与As-N-Na-H2O系φ-pH图的热力学分析结果一致，在453K时砷的最佳浸出率为95.85%。

英文摘要：

In order to illustrate the thermodynamic characteristics of arsenic during alkaline pressure oxidation leaching process oflead anode slime(NaNO3as oxidant;NaOH as alkaline reagent),theφ-pH diagrams of As-Na-H2O,N-H2O,As-N-Na-H2Osystems at ionic mass concentration of0.1mol/kg and temperatures of298,373,423and473K were established according tothermodynamic calculation.The results show that the existence forms of arsenic are associated with pH value,which mainly exists inthe forms of H3AsO4,24H AsO-,24HAsO-,H2AsO2-and As2O3in lower pH region,while it mainly exists in the form of3AsO4-when pH>11.14.High alkali concentration and high temperature are advantageous to the arsenic leaching.The alkaline pressureoxidation leaching experiments display that the tendency of arsenic leaching rate confirms the thermodynamic analysis resultsobtained from theφ-pH diagrams of As-N-Na-H2O system,and the highest leaching rate of arsenic reaches95.85%at453K.