Method for recycling sodium formate and sodium sulfite from waste sodium hydrosulfite liquid with sodium formate method

The invention relates to a method for recycling sodium formate and sodium sulfite from waste sodium hydrosulfite liquid with a sodium formate method. The method comprises the following steps of: carrying out precise filtration and ultrafiltration on waste sodium hydrosulfite liquid with the sodium formate method to remove insoluble substances and granular impurities in the liquid; and then introducing the liquid into a nanofiltration device for nanofiltration separation, wherein after being evaporated and concentrated, an obtained nanofiltration permeate solution can be used as a raw material of the sodium hydrosulfite and returned to a sodium hydrosulfite production station, and can also be continuously evaporated, concentrated, crystallized, centrifuged and filtered to obtain a sodium formate product of which the purity is higher than 95 percent; and an obtained nanofiltration concentrated solution can be introduced into an evaporator for concentrating and then is crystallized, centrifuged and filtered to obtain a crude sodium sulfite product. The method has the technical advantages of no secondary pollution, high purity of the sodium formate, simple process and easiness for industrial realization, wherein the purity can be up to higher than 95 percent.