Kinetics of Iron Removal From Ti-Extraction Blast Furnace Slag by Chlorination Calcination

Abstract

In this research, ammonium chloride was used to calcine Ti-extraction blast furnace slag (EBFS) with the aim of removing iron from it. The influences of calcination temperature, ammonium chloride to EBFS mass ratio and particle size on the rates of iron removal were investigated. The results show that the rate of iron removal increased to almost 100% with increases in calcination temperature and the NH4Cl to EBFS mass ratio, but decreased with increases in particle size. Iron is removed in the form of ferric chloride gas, and ammonium chloride can be recycled by recrystallization after decomposition. The bagdasarrym model was used to describe the calcination process at temperatures below 261°C, which was controlled by nonisothermal crystallization. The reaction kinetic equation was obtained and the apparent activation energy of 67.21 kJ/mol. Ferric chloride reaction product existed in the calcined slag in an amorphous solid state. The shrinking core model was used to describe the calcination process at temperatures above 261°C, which was controlled by surface chemical reactions. The reaction kinetic equation was obtained and the apparent activation energy was found to be 42.05 kJ/mol.

Keywords

• ti-extraction blast furnace slag
• iron removal
• chlorination calcination
• kinetics