The quality of the products, operational costs and environmental impact are important factors in the actual context of world economy globalization. The models are used to describe closer the real physicochemical processes that take place in a real plant. In this paper, the modeling and simulation of soda ash manufacturing process were done using ASPEN PLUS. The evolutions of the processes parameters (flows, composition, temperatures, pressures etc.) were studied during the synthesis steps: ammonia absorption into brine, carbonation process of ammoniacal brine and recovery of ammonia from the process wastewater. The simulation results were compared with real plant operation data in order to validate the applications. From the comparison, one can observe a close similarity between simulation results and the real plant data. This fact validates the applications developed for process simulation and proves the utility of the model in analyzing and optimization of the real plant operation.