Understanding the sodium migration mechanism during combustion process is critical for the clean and efficient utilization of high-alkali coals. In this paper, sodium releasing characteristics of five typical high-alkali coals are experimentally investigated based on occurrence mode and X-ray diffraction analysis. The experiments are conducted in a tube-furnace to investigate the sodium releasing and mineral transformation characteristics. The silica-alumina minerals in coal ash have a sodium fixation effect and therefore reduce the sodium releasing rate. However, calcium-containing minerals can weaken this effect. The mole fraction ratio of (Ca + Mg)/(Al + Si) in coal ash correlate well with the sodium release rate (considering occurrence forms), which is further proved by experiments. A new prediction formula for sodium release rate is proposed and validated therefore. It also demonstrates that, the sodium release rate of coal with a high‑calcium content is high, and much sodium is released in the gas phase at high temperatures, thus retaining the calcium minerals in coal ash. The sodium release rate of coal with high silicon and aluminum contents is low, and sodium remains in the coal ash in the form of aluminosilicate at high temperatures. Finally, the migration and transformation mechanism of sodium-containing minerals in high-alkali coals is concluded.

了解燃烧过程中钠的迁移机理对于高碱煤的清洁高效利用至关重要。本文基于赋存模式和X射线衍射分析，对五种典型高碱煤的钠释放特性进行了实验研究。实验在管式炉中进行，以研究钠释放和矿物转化特性。煤灰中的硅铝矿物具有固钠作用，因此降低了钠的释放速率。然而，含钙矿物质会削弱这种效果。粉煤灰中(Ca+Mg)/(Al+Si)的摩尔分数比与钠的释放速率（考虑赋存形式）有很好的相关性，实验进一步证明了这一点。因此，提出并验证了一种新的钠释放率预测公式。也说明高钙煤的钠释放率高，在高温下大量的钠以气相释放，从而保留了煤灰中的钙矿物质。硅、铝含量高的煤的钠释放率低，钠在高温下以铝硅酸盐的形式残留在煤灰中。最后总结了含钠矿物在高碱煤中的迁移转化机制。硅、铝含量高的煤的钠释放率低，钠在高温下以铝硅酸盐的形式残留在煤灰中。最后总结了含钠矿物在高碱煤中的迁移转化机制。硅、铝含量高的煤的钠释放率低，钠在高温下以铝硅酸盐的形式残留在煤灰中。最后总结了含钠矿物在高碱煤中的迁移转化机制。