Experimental Study on Oxidizing Roasting Process of Black Dross

The oxidizing roasting process of the black dross was investigated by X-ray diffraction, thermogravimetry–differential thermal analysis and thermodynamic calculation, and the effects of roasting conditions on the removal rate of AlN and salt flux in black dross were studied. The results show that the best roast conditions for oxidation of AlN are as follows: the roast temperature is about 800 °C, and the roast time is about 60 min. The removal rate of AlN is up to 93.8%. Salt flux in black dross can be removed in the form of flue gas, but it needs a higher temperature than AlN oxidation reaction. The removal rate of salt flux can reach 80% when it is roasted at 1200 °C for 60 min.