Dissolution Kinetics Of Salt Mixture ?Na₂CO₃+Na₂SO₄+NaCl? In Pure Water

The paper based on theory and law of salt-water system,mechanism and model of dissolution kinetics theory.Dissolution process of mixed salt?Na₂CO₃+ Na₂SO₄+ NaCl?under the condition of 15 oC,20oC and 25 oC was studied in this paper by means of chemical analysis and solid phase identification.Also,the dissolving process under different stirring speed,sample amounts and the amount of NaCl at 25 oC was studied.The dissolution kinetic equation was calculated by computer simulation adopting dynamic model,and the reaction order was obtained.The main research contents and conclusions are as follows.?1?The mixed salts were tableted is helpful to slow the dissolution rate of mixed salts?Na₂CO₃+ Na₂SO₄+ NaCl?.?2?Na₂CO₃ will react with Na₂SO₄ to form burkeite after the concentration reaches a certain extents during the dissolution process of mixed salts?Na₂CO₃+ Na₂SO₄+ NaCl?.Tablet compressing is advantageous to form burkeite,and burkeite was started to produce in 20 minutes after the mixed salts was dissolved.But there is no burkeite generated in the late of dissolution process.?3?Dissolution process of mixed salts?Na₂CO₃+ Na₂SO₄+NaCl?is an exothermic process.?4?At the early stage of the dissolution process,the stirring speed act as the dominant factor,but common ion effect will become the dominant factor after the three salts solution reach a certain concentration.At the same time,the generation of burkeite will impact the dissolution of mixed salts.?5?The stirring speed has little influence on the time required for each salt to reach a steady state.However,because of the same ion effect in the dissolution process,the stirring speed has a great influence on the dissolved concentration of the three salts.?6?With the increase of sample quantity,the dissolved concentration of Cl-and CO32-was increased,but the disslution concentration of SO42-was decreased.But the time required for Cl-and SO42-to reach a steady state was increased,the time required for CO32-to reach a steady state was basically the same.?7?With the increase of the amount of NaCl in the solute,the disslotion concentration of Cl-was increased,but the dissolved concentration of SO42-was decreased,while the dissolved concentration of CO32-was decreased slightly,but the effect was nit obvious.The time required for Cl-and SO42-to reach a steady state increases when the amount of NaCl was increased,but the time required for CO32-to reach a steady state is basically the same.?8?The dissolution kinetics equations of NaCl in the system were simulated,and get some better fitting results.The dissolution process was controlled by the diffusion process,and the dissolution process including interface reaction and diffusion process;some conditions are accompanied by chemical reactions.In the case of the chemical reaction in the system,the Stumm basic differential equation and its modified form are used.It is also proved that there is a chemical reaction in the system.