摘要
Efficient destruction of cyanide by thermal decomposition with ferric oxide addition was proposed. The mechanism of destruction of sodium cyanide with or without ferric oxide addition under various conditions was examined by XRD, DSC-TG, and chemical analysis technologies. In the absence of ferric oxide, sodium cyanide decomposes at 587.4 ℃ in air and 879.2 ℃ in argon atmosphere. In the presence of ferric oxide, about 60% of sodium cyanide decomposes at 350 ℃ for 30 min in argon, while almost all sodium cyanide decomposes within 30 min in air or O2 with mass ratio of ferric oxide to sodium cyanide of 1:1. The increase of ferric oxide addition, temperature, and heating time facilitates the destruction of sodium cyanide. It is believed that with ferric oxide addition, NaCN reacts with Fe2O3 to form Na4Fe(CN)6, Na2CO3, NaNO2 and Fe3O4 in argon. NaCN decomposes into NaCNO, Na4Fe(CN)6, minor NaNO2, and the formed NaCNO and Na4Fe(CN)6 further decompose into Na2CO3, CO2, N2, FeOx, and minor NOx in air or O2.
提出采用氧化铁催化热解高效除氰。采用XRD、DSC-TG、化学分析等手段对不同条件下添加和无添加氧化铁高效脱除氰化钠的机理进行研究。未添加氧化铁时,空气条件下,氰化钠在587.4℃开始发生分解;氩气条件下,氰化钠在879.2℃开始发生分解。添加氧化铁时,氩气条件下,大约60%的氰化钠在350℃热解30 min时发生分解;在空气或氧气条件下,当氧化铁与氰化钠质量比为1:1时,几乎所有的氰化钠在350℃热解30 min内完成脱除。研究表明,催化剂Fe2O3添加量的增加、除氰温度的升高及除氰时间的延长均有助于氰化钠的脱除。随着氧化铁的添加,氩气条件下,NaCN与Fe2O3反应生成Na4Fe(CN)6、Na2CO3、NaNO2和Fe3O4;空气或氧气条件下,NaCN分解生成NaCNO、Na4Fe(CN)6和微量的NaNO2,且形成的NaCNO和Na4Fe(CN)6随后发生分解,生成Na2CO3、CO2、N2、FeOx和微量的NOx。
基金
financial supports from the National Key R&D Program of China (2018YFC0604604)
the National Natural Science Foundation of China-Yunnan Joint Fund (U1702252)
the Fundamental Research Funds for Central Universities of China (N182506003)
the Key Scientific Research Project of Liaoning Province,China (2019JH2/10300051)。
