The agglomeration characteristics of river sand and wheat stalk ash mixture at various temperatures are investi- gated using a muffle furnace. The surface structural changes, as well as the elemental makeup of the sur...The agglomeration characteristics of river sand and wheat stalk ash mixture at various temperatures are investi- gated using a muffle furnace. The surface structural changes, as well as the elemental makeup of the surface and cross-section of the agglomerates, are analyzed by polarized light microscopy, scanning electron microscopy （SEM）, and energy dispersive X-ray （EDX）. Multi-phase equilibrium calculation is performed with FactSage in identifying the melting behavior of the river sand-wheat stalk ash mixture at high temperatures. No indication of agglomeration is detected below 850~C. At a temperature of 900-1000~C, however, obvious agglomeration is observed and the agglomerates solidify further as temperature increases. The presence of potassium and calcium enrichment causes the formation of a sticky sand surface that induces agglomeration. The main component of the agglomerate surface is KEO-42aO-SiO2, which melts at low temperatures. The formation of molten silicates causes particle cohesion. The main ingredient of the binding phase in the cross-section is K20-SiO2-Na20- Al2Oa--CaO; the agglomeration is not the result of the melting behavior of wheat stalk ash itself but the compre- hensive results of chemical reaction and the melting behavior at high temperatures. The multi-phase equilibrium calculations agree well with the experimental results.展开更多
基金supported by National Natural Science Foundation of China(Project Code:50706055)
文摘The agglomeration characteristics of river sand and wheat stalk ash mixture at various temperatures are investi- gated using a muffle furnace. The surface structural changes, as well as the elemental makeup of the surface and cross-section of the agglomerates, are analyzed by polarized light microscopy, scanning electron microscopy （SEM）, and energy dispersive X-ray （EDX）. Multi-phase equilibrium calculation is performed with FactSage in identifying the melting behavior of the river sand-wheat stalk ash mixture at high temperatures. No indication of agglomeration is detected below 850~C. At a temperature of 900-1000~C, however, obvious agglomeration is observed and the agglomerates solidify further as temperature increases. The presence of potassium and calcium enrichment causes the formation of a sticky sand surface that induces agglomeration. The main component of the agglomerate surface is KEO-42aO-SiO2, which melts at low temperatures. The formation of molten silicates causes particle cohesion. The main ingredient of the binding phase in the cross-section is K20-SiO2-Na20- Al2Oa--CaO; the agglomeration is not the result of the melting behavior of wheat stalk ash itself but the compre- hensive results of chemical reaction and the melting behavior at high temperatures. The multi-phase equilibrium calculations agree well with the experimental results.
