A sodium-zinc sorbent based flue gas desulfurization technology (Na-Zn-FGD) was proposed based on the experiments and analyses of the thermal decomposition characteristics of CaSO

3

and ZnSO

3

·2.5H

2

O

the waste products of calcium-based semi-dry and zinc-based flue gas desulfurization (Ca-SD-FGD and Zn-SD-FGD) technologies

respectively. Itwas found that ZnSO

3

·2.5H

2

O first lost crystal H

2

O at 100 ℃ and then decomposed into SO

2

and solid ZnO at 260 ℃ in the air

while CaSO

3

is oxidized at 450 ℃ before it decomposed in the air. The experimental results confirm that Zn-SD-FGD technology is good for SO

2

removal and recycling

but with problem in clogging and high operational cost. The proposed Na-Zn-FGD is clogging proof

and more cost-effective. In the newprocess

Na

2

CO

3

is used to generate Na

2

CO

3

for SO

2

absorption

and the intermediate product NaHSO

3

reacts with ZnO powders

producing ZnSO

3

·2.5H

2

O precipitate and Na

2

CO

3

solution. The Na

2

CO

3

solution is clogging proof

which is re-used for SO

2

absorption. By thermal decomposition of ZnSO

3

·2.5H

2

O

ZnO is re-generated and SO

2

with high purity is co-produced as well. The cycle consumes some amount of raw material Na

2

CO

3

and a small amount of ZnO only. The newly proposed FGD technology could be a substitute of the traditional semi-dry FGD technologies.