Crystal growth characteristics of RO phase microwave heating in steel slag
The effects of the melting and crystallization temperatures,holding time,and cooling rate on the growth of RO phase(an MgO-FeO-MnO solid solution)crystals in steel slag during microwave heating were investigated using thermogravimetric differential scanning calorimetry and optical microanalysis;hence,the crystal growth characteristics were derived.The results reveal that steel slag has a melting temperature of 1 400 ℃.The average particle size of the RO phase crystals increases with a decreasing cooling rate;however,an excessively low cooling rate yields an uneven crystal particle size distribution.For a cooling rate of 1 ℃/min,the RO phase-crystal particle size distribution is uniform and the grain boundaries are clear.As the crystallization temperature decreases,the average RO phase-crystal particle size increases.When the crystallization temperature is 1180 ℃,the average RO phase-crystal particle size is maximized,almost doubling from 26pm for the original crystal to 43pm.Therefore,particle growth is achieved for RO phase crystals in steel slag.A complete crystal morphology and clear grain boundaries are obtained.Finally,the total iron content of the separated post-treatment steel slag is 1.2 times that of the pre-treatment concentrate.
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