二氧化硫脲自热危险性的研究

为评价二氧化硫脲的自热特性，采用同步热分析仪STA和化学品恒温试验箱对其热分解过程进行了研究。考察了质量为250g的样品在温度为100℃、120℃、140℃、160℃、180℃、200℃的自热特性，并考察了质量分别为50g、75g、100g、150g、200g、400g、600g、800g的样品在温度100℃条件下的自热特性。结果表明，二氧化硫脲的分解温度为1250℃，分解热为6013J/g，最大放热速率418mW/mg；二氧化硫脲的自热过程是一个热分解过程，自热最低起始温度为95℃，峰值温度最小为2015℃，且与质量呈函数关系；试验发现现有的自热试验标准或测试方法对二氧化硫脲危险性的划分存在一定的缺陷，建议以样品起始自热温度为基准到样品的峰值温差来判定其是否发生自热。

Study on self-heating hazard of thiourea dioxide

The self-heating characteristics of thiourea dioxide were studied by means of synchronization thermal ana- lyzer and chemical temperature chamber. In this article, the self-heating characteristics of 25.0g sample at the tem- perature of 100℃, 120℃, 140℃, 160℃, 180℃ ,200℃ and 50g, 75g, 100g, 150g, 200g, 400g, 600g,800g sample at 100℃ were tested. The testing results showed that the decomposition temperature and enthalpy of which is 125.0℃ and 601.3 J/g respectively. The maximum heat release rate is 41.8mW/mg. Its self-heating is a ther- mal decomposition process. The thiourea dioxide starting with a minimal self-heating temperature of 95℃ and the peak temperature of self-heating is a function of mass with the minimal temperature of 201.5℃. There are some flaws in self-heating standards or test methods of thiourea dioxide in classification of dangerous. It ws suggested to use the difference between initial decomposition temperature and self-heating peak temperature when judging a chemical whether self-heating or not.