Studies On Preparing Sodium Hexafluoroantimonate And Determining The Solubility Of Sodium Hexafluoroantimonate

A new method of preparing qualified sodium hexafluoroantimonate in the solution directly has been proposed in this article in view of the problem of doing it traditionally in the anhydrous system.Two methods of adopting sodium antimonate and antimony white as the raw material have been tested respectively.At last,sodium antimonate is choosed as the raw material to do the pilot scale test,and qualified sodium hexafluoroantimonate product has been prepared.Meanwhile,solubility of sodium hexafluoroantimonate has been determined to instruct this preparation process,and experiment has been conducted to make sure the main affecting factors of its solubility.Firstly,the process of preparing sodium hexafluoroantimonate using sodium antimonate as the raw material has been tested.The effects of dissolve temperature,the dosage of H₂O₂,the dosage of NaF on the quality of hexafluoroantimonate have been investigated.The best preparing conditions has been determined:NaSb(OH)₆:HF=1:6.5,the amount of hydrogen peroxide to the theory 1.1 times,the dissolve temperature 80℃;,dissolve time 2h,the amount of NaF 0.50%.Secondly,the process of preparing sodium hexafluoroantimonate using antimony white as the raw material has been tested.The effects of dissolve temperature,the addition time of H₂O₂,the dosage of NaOH on the quality of hexafluoroantimonate have been investigated.The best preparing conditions has been determined:Sb₂O₃:HF:H₂O₂=1:12:2,the addition time of H₂O₂ 20 min,the dissolve temperature 80℃;dissolve time 2h,the excess coefficient of NaOH 1.05.According to the quality requirement of sodium hexafluoroantimonate, the pilot scale test using sodium antimonate as the raw material have been accomplished.The main components of sodium hexafluoroantimonate were as follow(%):Sb 46.98,Sb(â…¢)0.033,F 43.85,F(dissociative)0.43,Na8.86;The production cost of sodium hexafluoroantimonate was about 31460 yuan per ton.The method has been applied in industrial production.The constant temperature dissolve equilibrium method was applied to determine the solubility of sodium hexafluoroantimonate in different temperature.The solubility of sodium hexafluoroantimonate in 45℃is 634.8 g·L^-1.The effects of equilibrium time,dissolve temperature,the dosage of NaF, the dosage of HF on determining the solubility of sodium hexafluoroantimonate have been investigated.When equilibrium time is over 8h,the solubility of sodium hexafluoroantimonate in the dissolution process and the crystallization process are consistent.The solubility of sodium hexafluoroantimonate would increase with the temperature rise.The solubility of sodium hexafluoroantimonate decreases gradually with the increasing of the dosage of NaF between 0.5 and 1.5%(weight ratio).The solubility of sodium hexafluoroantimonate would increase gradually with the increasing of the dosage of HF between 0.5 and 1.5%(Volume ratio).