In order to concentrate the diluted sulfuric acid from the titanium dioxide (TiO

2

) production of sulphate process

a new concentration process was proposed by coupling chemical dehydration and multi-effect evaporation. The ferrous sulfate monohydrate (FeSO

4

·H

2

O)

as the dehydrant

was added to the diluted sulfuric acid to form ferrous sulfate heptahydrate (FeSO

4

·7H

2

O) according to the H

2

SO

4

-FeSO

4

-H

2

O phase diagrams

which partially removes the water. This process was named as Chemical Dehydration Process. The residual water was further removed by two-effect evaporation and finally 70 wt% sulfuric acid was obtained. The FeSO

4

·H

2

O can be regenerated through drying and dehydration of FeSO

4

·7H

2

O. The results show that FeSO

4

·H

2

O is the most suitable dehydrant

the optimal reaction time of chemical dehydration process is 30 min

and low temperature is favorable for the dehydration reaction. 45.17% of the entire removed water can be removed by chemical dehydration from the diluted sulfuri

c acid. This chemical dehydration process is also energy efficient with 24.76% saving compared with the direct evaporation process. Furthermore

51.21% of the FeSO

4

dissolved originally in the diluted sulfuric acid are precipitated out during the chemical dehydration

which greatly reduces the solid precipitation and effectively alleviates the scaling in the subsequent multi-effect evaporation process.