Liquid Ion-Exchange Extraction For The Recovery Of Hydroxylamine Sulfate From Raschig Synthesis Mixtures: Application And Relative Study

There are many industrial process lines for production of hydroxylamine sulfate by Raschig synthesis method in China.However,the high purity solid hydroxylamine sulfate needs by China are imported from other countries.This is because the production of hydroxylamine sulfate by Raschig process is a mixture of aqueous solution containing high proportion of ammonium sulfate.The separation of hydroxylamine ion,NH₃OH⁺,from ammonium ion,NH₄⁺ in Raschig mixture remains difficulties.The needs of hydroxylamine sulfate are grow rapidly in China as the development of Nilon,medicine and digaital PCB industry.The recovery of hydroxylamine sulfate from Raschig mixtures is meaningful.In this work,the Liquid Ion-exchange Extraction was applied for the recovery of hydroxylamine sulfate from Raschig synthesis mixtures.Some key problems in this process were investigated,such as method to simultaneously analysis ions in solution,thermodynamics equilibrium in ion-exchange extraction,and physical properties in extraction phase.Meanwhile,the relative theory and modeling in these subjects were investigated.The main contents are generalized as follows:1.The potentiometric titration multivariate calibration method are applied to simultaneously determine H⁺,NH₃OH⁺ and NH₄⁺ in Raschig mixtures.A novel method based on Moving window(MW) strategy has been proposed to simultaneously choose the optimal pH region and latent variables(LVs) number for PLS regression in potentiometric titration multivariate calibration.In this method,the leave-one-out cross-validation with varying LVs number is run on different selected moving window and,consequently,that revealing optimal results is selected.The results show that calibration models constructed from titration data subjected to MW pre-treatment provide improvements in reducing both data dimension and prediction error.2.The liquid-liquid ion extraction equilibrium of NH₄⁺ salt of bis(2-ethylhexyl) phosphoric acid in kerosene with Raschig mixture is investigated in different aqueous salt and organic extractant concentrations.An improved model incorporating Pitzer's equations for calculation of thermodynamic properties of aqueous salts solutions was implemented into liquid ion-exchange extraction.The experimental equilibrium data can be correlated well by the proposed model.3.A new one parameters model for binary mixtures based on Eyring absolute rate theory and Flory Huggins equation is presented.The new model was tested with 462 binary systems (include 84 binary alkane mixtures),with AAD%of 1.42%,while 2.25%for Grunberg-Nissan equation.The model can also apply to correlate viscosity data of Ionic liquid+dilution systems, with AAD%of 3.96%,while 6.96%for Grunberg-Nissan equation.4.Densities and viscosities of binary mixtures of Tri-n-butyl phosphate with cyclohexane, and n-heptane have been measured over the entire range of composition at T=(288.15,293.15, 298.15,303.15,and 308.15) K and atmospheric pressure.Densities and viscosities of binary mixtures of Tris(2-ethylhexyl)phosphate with cyclohexane,or n-hexane have been measured over the entire range of composition at T=(293.15,298.15,and 303.15) K and atmospheric pressure.The new one parameter model proposed by this work for liquid mixture viscosity was applied to correlate the experimental viscosity data.In addition the new group of phosphate is defined for Unifac-Visco model.The interaction parameters of new Unifac-Visco group were obtained by regression the viscosity data from this work and literatures.5.The densities of aqueous solution of pure hydroxylamine sulfate at T=(283.15,288.15, 293.15,298.15,303.15,308.15,313.15) K and solution of hydroxylamine sulfate containing ammonium sulfate at T=(293.15,298.15,303.15,308.15,313.15) K have been determined. The viscosities of these binary and ternary mixtures at T=(298.15,303.15,308.15) K are also presented.The Masson-type equation and extended Jones-Dole equation in terms of ionic strength are used to correlate the density and viscosity of aqueous solution of hydroxylamine sulfate,respectively.The ideal mixing rule of Young's has been applied to predict the ternary densities and viscosities of aqueous hydroxylamine sulfate+ammonium sulfate solution.