Solid And Liquid Phase Equilibrium And Dynamics For The Reforming Process To Produce Calcium Hypophosphite

With the development of technology,calcium hypophosphite a common salt is used more and more widely,the traditional production method can not satisfied the demand of now.The transformation method of calcium hypophosphite can get high purity,uniform particle size of the product.The production method is double decomposition reaction.To improve the reaction conversion rate,the purity of the product,further optimize the process,the relevant phase diagram need to research.At present,the laboratory determined the phase diagram of Na⁺,Ca²⁺//Cl^-,H₂PO₂^--H₂O interaction quaternary system at 298.15k.But phase diagram data of other temperature is not perfect and need to further study.In this paper,the phase diagram of Na⁺,Ca²⁺//Cl^-,H₂PO₂^--H₂O interaction quaternary system at 325.15k was measured.The results are as follows:1.The solubility of sodium hypophosphite in water is affected by temperature and as temperature increases,which is relatively large in the range of 0?-100?.calcium hypophosphite solubility is not affected by temperature.With increasing temperature within the range of 0?-100? solubility of calcium hypophosphite decreased slightly.2.The study of ternary phase diagram adopted the method of isothermal.The study found:the system of CaCl₂^-Ca?H₂PO₂?₂^-H₂O is simple ternary system.There are two solid phase area and a eutectic point of two salt.The solid salt is CaC₂·H₂O,Ca?H₂PO₂?₂ respectively.Solid phase area of calcium hypophosphite is larger,smaller solubility;Ca?H₂PO₂?₂^-NaH₂PO₂^-H₂O system is complex ternary system.There are there solid phase area and two eutectic point of two salt.The solid salt are Ca?H₂PO₂?₂.NaH₂PO₂·H₂O?NaCa?H₂PO₂?₃ respectively.NaCa?H₂PO₂?₃ is a double salt,Which is unstable double salt.The solid-phase area of double salts is larger,smaller solubility.The system of NaCl-NaH₂PO₂^-H₂O is simple ternary system.There are two solid phase area and a eutectic point of two salt.The solid salt is NaCl?NaH₂PO₂·H₂O respectively.The solubility of sodium hypophosphite is larger so the solid phase area is smaller.3.The research of the quaternary system is still adopted isothermal method.The study found:the system of Na⁺,Ca²⁺//Cl-H₂PO₂^--H₂O have five solid phase area,seven two salt eutectic curve,three eutectic point of there salt and five eutectic point of two salt.There is not double salt in the system.The Solid phase area of calcium hypophosphite is the largest.The Solid phase area of sodium hypophosphite is the smallest.The eutectic line of NaCI-Ca?H₂PO₂?₂ show this method is feasible to produce calcium hypophosphite.The presence the eutectic line of sodium chloride,calcium hypophosphite and double salt,this double salt can interfere with product yield and quality methods.