Method and apparatus for treating acidic gas

The invention provides a method for treatinga acidic gas, which comprises following steps: (A) employing a first processor for receiving and treating the acidic gas to obtain a gas-phase material flow (1) and a liquid-phase material flow (2), wherein the material flow (2) is totally or partially recycled to the first processor; (B) employing a second processor for treating the material flow (1) from the first processor to obtain a gas-phase material flow (3) and a liquid-phase material flow (4) ; (C) employing a third processor for treating the material flow (3) from the second processor to obtain a gas-phase material flow (5) and a liquid-phase material flow (6); and (D) employing a fourth processor for receiving and treating a material flow (43) from the second processor and treating the gas-phase material flow (5) from the third processor to obtain a gas-phase material flow (7) and a liquid-phase material flow (8). The invention also provides an apparatus for treating the acidic gas.