煤灰的熔融特性是气化用煤的重要指标,添加助熔剂是降低高灰熔点煤灰熔融温度的主要方法。复合助熔剂可利用不同组分间的协同作用,显著降低助熔剂添加量,提高煤气化整体效率。选取钢渣(GZ)和赤泥(CN)两种工业固废制备复合助熔剂,考察气化条件下复合助熔剂对高灰熔点潞安煤(LA)灰熔融特性的影响,并分析了高温下煤灰中矿物质的变化。结果表明:添加量为2%~8%的钢渣、赤泥和钢渣与赤泥制备的复合助熔剂,均能降低潞安煤灰的熔融温度,且随钢渣与赤泥混合质量比的增加,潞安煤灰的熔融特征温度呈“V”型变化;钢渣与赤泥对降低潞安煤灰的熔融特征温度存在显著的协同作用,且协同作用与添加量、钢渣与赤泥的混合质量比密切相关;添加量为2%与混合质量比为9∶1、添加量为4%与混合质量比大于5∶5、添加量为6%和8%与所有混合质量比条件下,添加复合助熔剂后潞安煤灰的熔融特征温度均低于单独添加钢渣、赤泥后潞安煤灰的熔融特征温度。高温下潞安煤灰矿物质组成表明,添加量为2%与混合质量比为9∶1,添加复合助熔剂显著降低了潞安煤灰中莫来石和硅线石的含量;添加量为4%~8%,高温下潞安煤灰中钠长石与钙长石、方钙石、钙铝黄长石等含钙矿物质发生低温共熔,这是复合助熔剂对降低潞安煤灰熔融特征温度存在协同作用的根本原因。

Fusibilty of coal ash is an important parameter for coal gasification.  Addition of  flux is widely used to lower the high ash melting point coal ash fusion temperatures.  The complex flux  can significantly reduce the dosage of flux, improving the overall efficiency of coal gasification for the  synergistic effect between different components.  In this study, the impact of complex flux agents pre‐ pared from industrial solid waste, steel slag(GZ) and red mud(CN), the influence of complex flux on  ash fusibility of high ash melting point Lu’an coal (LA) ash was investigated, and the mineral trans‐ formation was analyzed by experiment and calculation.  The results show that addition amount of  2%−8% GZ, CN and complex flux can effectively lower the ash fusion temperatures (AFTs) of LA  ash.  As the mixing mass ratio of GZ and CN increases, the AFTs show a V-shaped variation; the  combination of GZ and CN has a significant synergistic effect on reducing the melting characteristic  temperature of Lu’an ash, and the synergistic effect is closely related to the addition amount and the  mixing mass ratio of GZ and CN; the AFTs of Lu’an ash with composite flux is lower than that with  GZ and CN alone, when the addition amount is 2% and the mixing mass ratio is 9∶1, or the addition  amount is 4%, the mixing mass ratio is greater than 5∶5, or the addition amount is 6 % and 8% with  all mixing mass ratios.  The mineral composition at high temperature demonstrates that when the addi‐ tion amount and the mixing mass ratio are 2% and 9∶1, the contents of mullite and sillimanite in Lu’ an ash at high temperature are significantly reduced; when the addition amount is 4%−8%, the low- temperature eutectic is formed between albite and anorthite, calcite, gehlenite and other calcium- containing minerals at high temperature.  These accounted for the synergistic effect of the composite  flux on reducing theAFTs of Lu’an ash.