A plant originally used mirabilite and coal to calcine sodium sulfide, but the single furnace at certain low yield level, adding hugely to production costs.Now the factory to be used semi-coke powder instead of coal to calcine sodium sulfide.After anal. the feasibility of semi-coke powder instead of coal in the process, the calcination experiments with semi-coke powder and mirabilite.This paper first analyzes the optimal dosage of mirabilite in each converter, and then use four converters to do parallel test, compared the content of sodium sulfide in crude black ash with the before calcination products, then compared the two results to the best material.The results showed that this alternative process could save raw material inputs and reduce the cost of raw materials, the average per ton of water reduction alkali can save the cost of 60.91 yuan.In addition, it could also make the average yield of single furnace was increased by 2.579 t/d.