(昆明理工大学 冶金与能源工程学院，昆明 650093)
摘 要: 采用水热臭葱石沉砷法研究高砷含铁溶液沉砷过程中钠离子及其它宏观技术参数对沉砷渣物相组成、目标元素含量、形貌特征、砷铁沉淀率以及沉砷渣中黄钠铁矾、碱式硫酸铁、次水合砷酸铁(FeAsO4？0.75H2O)等亚稳态铁物相转变行为的影响规律。结果表明：体系中Na+的存在对水热臭葱石沉砷过程的影响显著，初始Na+浓度为5 g/L时，形成以臭葱石、次水合砷酸铁为主并伴有部分亚稳态黄钠铁矾生成的沉砷渣，随着初始Na+浓度的升高，有利于黄钠铁矾的生成，渣中 震动吸收峰随之增强，臭葱石的形成逐步受到抑制；当Na+浓度达到10 g/L时，沉砷渣物相以次水合砷酸铁和黄钠铁矾为主，此时As、Fe的沉淀率分别为98.2%、93.3%，沉砷渣中Na、S的含量分别高达1.7%、4.6%。适当降低初始pH、缩短反应时间、降低反应温度均可抑制亚稳态黄钠铁矾物相的形成，有利于获得纯度较高的臭葱石沉砷渣；同时，延长反应时间可实现次水合砷酸铁向臭葱石的转化。
关键字: 水热法；臭葱石；钠离子；黄钠铁矾；次水合砷酸铁
（Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China）
Abstract:The effects of sodium ion and other macro-technical parameters on the phase composition, target element content, morphology, precipitation rate of arsenic and ferric in precipitation and the phase transition behavior of metastable ferric, such as Na-jarosite, basic ferric sulfate and ferric arsenate sub-hydrate (FeAsO4 0.75H2O) in arsenic-containing solution during scorodite precipitation, were studied. The results show that the presence of Na+ in the system has a significant effect on the arsenic fixation process of hydrothermal scorodite precipitation, when the initial concentration of Na+ is 5 g/L, scorodite and ferric arsenate sub-hydrate as the main components and partial metastable Na-jarosite are formed. With the increase of initial Na+ concentration, the vibration absorption peak in the precipitation is enhanced, and the formation of scorodite is gradually inhibited. When the concentration of Na+ reaches 10 g/L, the main phase of the precipitate is ferric arsenate sub-hydrate and Na-jarosite. At this time, the precipitation rates of As and Fe are 98.2% and 93.3%, respectively. The contents of Na and S in precipitate are as high as 1.7% and 4.6%, respectively. The formation of metastable Na-jarosite phase can be inhibited by properly reducing initial pH, reaction time and reaction temperature, which is conducive to obtaining scorodite precipitate with high purity. At the same time, the conversion of ferric arsenate sub-hydrate to scorodite can be realized by prolonging the reaction time.
Key words: hydrothermal method; scorodite; sodium ion; Na-jarosite; ferric arsenate sub-hydrate
