Pulp bleaching agent FAS|Thiourea Dioxide-FAS is one kind excellent pulp and paper bleaching agent, FAS can be used in reduction bleaching, waster paper deink bleaching. FAS is very stable in air and can be used under the normal equipments. Because of high reducibility and good stability, FAS is very suitable for high temperature continual bleaching, and there is good for environment, does not increase the waste water pollution load, conforms to the environmental protection requirements.