Method for preparing sodium sulfite by utilizing total alkali in hydrazine hydrate

The invention provides a method for preparing sodium sulfite by utilizing total alkali in hydrazine hydrate, belonging to the technical field of hydrazine hydrate. The method comprises the following steps of: adding one or several kinds of raw materials of SO2 gas, NaHSO3 or Na2S2O5 to a hydrazine hydrate solution until the pH value of the hydrazine hydrate solution is 6.0-7.0, cooling and crystallizing the hydrazine hydrate solution, and then carrying out solid-liquid separation to obtain Na2SO3.7H2O. The invention overcomes the defects of high energy consumption, high cost and the like when the traditional process is used for extracting hydrazine hydrate byproducts and provides the method for preparing the sodium sulfite by utilizing total alkali in the hydrazine hydrate; the whole production process does not have three-waste discharge and has low energy consumption, and the produced products have high additional values.