In this study

a route for simultaneous mineralization of CO

2

and production of titanium dioxide and ammonium alum

and microporous silicon dioxide from titanium-bearing blast furnace slag (TBBF slag) was proposed

which is comprised of (NH

4

)

2

SO

4

roasting

acid leaching

ammonium alum crystallization

silicic acid flocculation and Ti hydrolysis. The effects of relevant process parameters were systematically investigated. The results showed that under the optimal roasting and leaching conditions about 85% of titanium and 84.6% of aluminum could be extracted while only 30% of silicon entered the leachate. 84% of Al

3+

was crystallized from the leachate in the form of ammonium aluminum sulfate dodecahydrate with a purity up to 99.5 wt%. About 85% of the soluble silicic acid was flocculated with the aid of secondary alcohol polyoxyethylene ether 9 (AEO-9) to yield a microporous SiO

2

material (97.4 wt%) from the crystallized mother liquor. The Al- and Si-depleted solution was then hydrolyzed to generate a titanium dioxide (99.1 wt%) with uniform particle size distrib

ution. It was figured out that approximately 146 kg TiO

2

could be produced from 1000 kg of TBBF slag. Therefore

the improved process is a promising method for industrial application.