Comparison of Magnesium Oxide Extraction from Victorian Brown Coal Fly Ash and Steel Making Slag Using Regenerative Ammonium Chloride
نویسندگان
چکیده
In this study, the treatment of fly ash and steel making slag in aqueous ammonia chloride has been conducted. These zero-value wastes have distinctively high concentrations of magnesium, calcium and iron. The ammonium chloride has been employed as the leaching reagent to extract MgO out of fly ash and slag, and the dissolved cations in the leachate were subsequently precipitated by carbonation. Two types of fly ashes from different power plants (Hazelwood and Yallourn) and typical Steel making slag have been tested in a five-cycle test to assess the leaching capability of the regenerated ammonium salt upon recycling and to study the effect of impurities on leaching and carbonation percentage of fly ash and slag. Carbonation percentage of more than 90 and 80% for Hazelwood fly ash and steel making slag respectively led to successful extraction of MgO. Negligible extraction of magnesium was confirmed for Yallourn fly ash, due to the strong association of MgO and Fe2O3 as spinel.
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