Predicting Solubility Of Electrolyte In Concentrated-seawater And Developing Of Data Analysis Platform

Extracting mineral crystal from concentrated-seawater is a promising technology,which classifies the concentrated-seawater as electrolyte solution.The solubility data iscritical.Exhaustively experimental detemination of such system is impossible.It is necessaryto use a theoretical model to obtain the electrolyte solubility.Based on both Pitzer equations and chemical equilibrium principle,the work builds asolubility product-oriented equilibrium equation,at the same time proposes a kind ofdynamic algorithm to predict the numerical solution of nonlinear equations.For accessing tothe real solution,the algorithm starting from a initial value,sequentially adds or subtracts astep to the concentration.When the concentration is far away from the real solution,using along step to ensure the convergence speed.On the contrary,using a short step to ensure theaccuracy.The step is dynamically adjusted according to the twice adjacent return values.Thecalculation effects of the algorithm for serveral brine systems prove that this methodperforms well.The relative error is not more than1%,the relationship between lterations andaccuracy is linear and the initial value doesn’s affect the convergence.Actually thethermodynamic data in a large temperature range is necessary.To break the limit that thePitzer equation is only appropriate at25°C,this work presents a methodology for thedetermination of the temperature dependency of the Pitzer’s parameters and the solubilityproduct.The influence of temperature is taken into account using only mixingenthalpies.The relative error is less than5%.A data analysis platform is developed for data sharing and automated calculation.Thegraphical interface is available and the Pitzer equations,solubility algorithm,temperatureparameter fixing are integrated in the platform.With the software,users can implementthermodynamic calculation and data management.