摘要
煤灰的熔融特性不仅与煤灰的化学组成有关,还与灰成分的矿物形态有关,其中酸性氧化物可提高煤灰熔融温度,碱性氧化物却呈现降低煤灰熔融温度与助熔剂的作用。煤灰熔融温度与相平衡性质的良好相关性,可利用三元相图来预测和解释。据此通过添加不同助剂与煤灰中氧化物相互作用生成高熔点或低熔点物质的方法可改变煤灰熔融特性,以适应不同排渣方式和气化工艺的选择;同时将经碱盐催化气化后的煤灰添加适当助剂煅烧后可使其中形成玻璃网络的氧化物(如SiO2)与修饰中间氧化物(Al2O3、Fe2O3等)和修饰网络氧化物(Na2O、CaO、MgO等)相互作用形成新的稳定硅酸盐复合物,实现了含碱灰渣的煅烧脱碱无害化。
Coal-ash fusibility exhibits corresponding relations to its chemical composition and mineral composition, in which acidic oxides can increase the ash fusion temperature, but the basic oxides play a role in helping fusion and can reduce the ash fusion point. Since the ash fusion temperature always depends on the final multi-phase equilibrium of coal-ash composed of various element compositions, the ternary phase equilibrium diagram could often be used to predict and explain the variations of ash fusion temperature. The above important results show not only adding different additives into the coal-ash changes its ash fusibility, which has been effectively applied to select a suitable way in discharging ash-slag and for coal gasification process, but also adding appropriate additives into the alkaline coal-ash, yielded from coal catalytic gasification, forms a stable silicate compound, which resulted from the interaction among the vitreous lattice oxides (e. g. SiO2), the modified median lattice oxides (Al2O3, Fe2O3, etc.) and modified meshwork oxides (Na2O, CaO, MgO, etc.) under a certain calcinations temperature, which has been successfully adopted for the harmless treatment for the alkaline coal-ash.
出处
《现代化工》
EI
CAS
CSCD
北大核心
2005年第5期22-26,28,共6页
Modern Chemical Industry
基金
国家自然科学基金(20376014)
福建省科技厅重点资助项目(HG99-01)
