Sodium sulfate and ammonium sulfate composite salt heat decomposition to prepare sodium bisulfate process research

• 1、UniversityofScience&TechnologyBeijing,Institute of Engineering,ChineseAcademy of Sciences
• 2、Institute of Process Engineering,Chinese Academy of Sciences

Abstract：Treating and reasonably utilizing high-salinity wastewater is a challenging problem for the comprehensive management of such waste by many production enterprises. High-salinity wastewater containing sodium sulfate and ammonium sulfate is generated during processes in the chemical industry, wet metallurgy, petroleum refining, as well as the preparation of ternary precursors. Studying how to utilize high-salinity wastewater containing sodium sulfate and ammonium sulfate as a resource is of significant practical importance. Currently, the main methods of treating high-salinity wastewater containing these compounds are preparation of Yuan ming powder by deamination and crystallization. This article, building upon the traditional methods for treating wastewater with high concentrations of sodium sulfate and ammonium sulfate, will propose a comprehensive treatment approach for high-salinity waste water. In this paper, the thermal decomposition of ammonium sulfate by sodium sulfate was used to prepare sodium bisulfate. The thermodynamic analysis was carried out with the reaction temperature, reaction time and molar ratio of the reactants (sodium sulfate: ammonium sulfate) as variables, the hydrogen ion content, the ammonia nitrogen content, the sulfate radical content and the sodium ion content in the residue product are calculated as the indexes, the process conditions of preparing sodium bisulfate by thermal decomposition of ammonium sulfate with sodium sulfate were studied. The experimental results show that the conversion of the reaction can reach 78% when the reaction temperature is 380℃, the reaction time is 7 h and the molar ratio of the reactants (sodium sulfate: ammonium sulfate) is 1:1 under different steam conditions When the reaction temperature is 380℃, the reaction time is 7 h and the molar ratio of reactants (sodium sulfate: ammonium sulfate) is 1:1, the conversion of the reaction can reach 82 % . The introduction of water vapor can reduce the reaction temperature of double salt decomposition and promote the decomposition of double salt.

Keywords： Sodium sulfate Ammonium sulfate Sodium bisulfate Thermal decomposition Water vapor