无烟粉煤催化气化含碱灰渣的煅烧脱碱

Calcination de-alkali of alkali coal-cinder yielded from catalytic gasification for pulverized anthracite

在具有温控的小型高温加热炉中,通过静态煅烧研究了温度、时间及助剂对高变质程度无烟粉煤催化气化后的含碱灰渣中碱含量的影响,结果表明:最佳的脱碱煅烧温度及时间分别为870℃和30min;最佳的脱碱助剂高岭土在其添加浓度为5%时,灰渣脱碱率可达100%.采用X射线粉晶衍射及扫描电镜对煅烧后的灰渣进行表征,揭示了含碱灰渣煅烧脱碱过程的实质,即在适宜煅烧温度下,含碱灰渣中被活化的主要矿物质SiO2(形成玻璃网络氧化物)、Al2O3(修饰中间氧化物)和熔融并分解的Na2CO3(分解为修饰网络氧化物Na2O)等发生化学反应转变为中性物质霞石(NaAlSiO4)及其他无定形复合硅酸盐,从而降低了灰渣中的碱含量.

The effects of calcination temperature, time and additives on the alkali content of coal-cinder from the catalytic gasification of pulverized anthracite were examined by using the static calcination method in a laboratory high temperature furnace in this study. The results indicated that the optimum calcination temperature and time were respectively 870℃ and 30 min, and the optimum dealkalization additive is kaolinite. By adding only 5 % kaolinite in the calcination process, the dealkalization rate could be increased to 100%. Most importantly, with analyzing the calcined cinder by X-ray powder diffraction （XRD） and scanning electron microscope （SEM）, it was clear that at an appropriate calcination temperature, the activated SiO2 and Al2O3 in alkaline coal-cinder would react with the decomposed fused Na2CO3 to form a new neutral matter nepheline （NaAlSiO4） and other amorphous silicate compounds, causing an obvious reduction of the alkali content in coal-cinder.