Preparation And Far Infrared Emission Properties Of Iron Ore Tailings Composite Ceramics

Far-infrared functional ceramics, mainly prepared by transition metal oxide, zirconium oxide, quartz, cordierite, etc, exhibit broad application prospects in saving energy and human health care. In this work, iron ore tailings was regarded as the main object, through optimizing the batching and burning system, we have successfully prepared iron ore tailings composite ceramic materials with infrared emission properties, and also studied its far-infrared emission mechanism and influence factors, which is a new way for the high value-added functional application of iron ore tailings resources.By analyzing the chemical composition of iron ore tailings, iron ore tailings, calcium, and silica were designed as raw materials of far-infrared ceramics,tourmaline and rare earth were used separately as additives in order to further improve the far-infrared emission properties of ceramics. The mass ratio of iron ore tailings, calcium, and silica were 6:1:1 in raw materials. The sintering and melting temperature of tourmaline composite iron ore tailings ceramics are 1065-1075oC and 1075-1081oC, respectively; while that of rare earth composite iron ore tailings ceramics are 1062-1070oC and 1065-1075oC, respectively.The analysis of TG-DTA and hot stage microscope were used to study the effects of tourmaline and rare earth on the densification sintering of iron ore tailings ceramics. With increasing the content of tourmaline, iron ore tailings composite ceramics’ density increased from 1.68 g/cm3 to 1.96 g/cm3, and its sintering temperature reduced from 1070℃ to 1065℃. With increasing the content of rare earth, iron ore tailings composite ceramics’ density increased from 1.65 g/cm3 to 1.79 g/cm3, and its sintering temperature reduced from 1070℃ to 1062℃. Kissinger method was used to calculate the activation energy for raw materials in the process of heating. For tourmaline composite iron ore tailings ceramics, the activation energy of carbonate decomposition are 209.39 ~ 233.37 k J/mol, activation energy of sintering are 101.79~174.36 k J/mol. For rare earth composite iron ore tailings ceramics, the activation energy of carbonate decomposition are 191.53~223.41 k J/mol, activation energy of sintering are 96.880~164.16 k J/mol. Both of tourmaline and rare earth are conducive to speed up the reaction rate, and promote the sintering of iron ore tailings ceramics.The emission mechanism of ore tailings composite ceramics of was established based on the two aspects of crystal structure and vibration of the chemical bond. The far-infrared emission of ceramics increased first and then decreased both with increasing the tourmaline and rare earth contents. When adding 5 wt.% tourmaline, its peak value of far-infrared emission is 0.925. Fe2+ from tourmaline replaced Ca2+ to form isomorphism, which enhanced the Ca-O vibration in diopside, then improved its far-infrared emission. When adding 7 wt.% rare earth, its peak value of far-infrared emission is 0.914. Rare earth Ce4+ formed solid solution with iron diopside, which enhanced the vibration of Mg-O in octahedral and Fe-O in tetrahedron, thus the far-infrared emission was improved.