The invention relates to a dry purification of emitted 
smoke dust containing 
fluoride, 
tar, dust and other harmful substances, in particular to a carbon 
roasting smoke dust dry purification method and a device thereof, the suction of an induced draft fan leads the 
smoke dust to enter a dry 
bottom type cooler to carry out the cooling process to lower the temperature, aluminum 
oxide in a reactor is utilized as an absorbent to carry out the absorption process of the 
fluoride, the 
tar and other harmful substances in the smoke dust, the separation 
filtration process of gas and the mixed 
solid is carried out in a bag 
dust collector, after the separation 
filtration, the gas is discharged from a 
chimney by the induced draft fan, the aluminum 
oxide is recycled, and other aluminum 
oxide containing the absorbed substances enters a collecting chamber by the collection as raw materials of electrolytic aluminum for standby. The process flow of the invention is simple, the one-time purification of the smoke is thorough, no 
pollution is generated, the aluminum oxide can be simultaneously recycled, the technology is advanced, the degree of 
automation is high, the production operation cost is effectively reduced, the technology is economic and reasonable, the removing efficiency of the smoke dust can achieve more than 99 percent, the content of the smoke dust in the emitted smoke dust is 10mg / Nm<3>, the content of 
tar is 10mg / Nm<3>, and the content of 
fluoride is 1mg / Nm<3>, which are higher than the national emission standards.