Study On Resource Recovering Of Carbonate Heavy Oil Deposit Reactive Extraction Wastewater

Carbonate heavy oil deposit reactive extraction wastewater has strong acidity,high concentration of heavy metal ions and large amount of waste liquor.If it is not properly handled,it will not only cause serious environmental pollution,but also causes a great waste of resource.In this paper,chemical precipitation and crystallization coupling technology was used for the recovery of the wastewater,which provided a theoretical basis for the future of industrialization.In this paper,the simulated wastewater was prepared by the reaction of formic acid with Indonesian oil sand residue.The effect of formic acid dosage,initial water addition and stirring time on the preparation process were investigated according to single factor experiments.The main metal ions in oil sand residue and solution were characterized by XRF and ICP.By comparing the removal efficiency of different pH values and two kinds of alkali on metal ions,calcium hydroxide was selected to remove neutralized slag at pH 8 in this paper.It could remove some impurity ions for the recovery of high purity calcium formate,and achieve the effective enrichment of iron and aluminum ions.The solubility of calcium formate in pure water and four different binary solvent mixture at different temperatures were determined by gravimetric method.Results in-dicated that the solubility of calcium formate increased slightly with the increase of temperature and decreased significantly with the increase of organic solvent content in binary solvents.The Apelblat equation,CNIBS/R-K equation and Jouyban-Acree equa-tion were applied for the correlation of experimental solubility.These thermodynamic models were all in good agreement with the experimental values.Besides,the thermo-dynamic parameters including enthalpy,entropy,and Gibbs free energy were calculated,which provided data basis for subsequent crystallization process.According to single factor experiments,the effect of water evaporation quantity,evaporation rate,stirring rate and adding seed were investigated on the purity,particle size and morphology of calcium formate.And the optimum crystallization parameters were determined.The differences of energy consumption and crystal form between dis-solution crystallization and vacuum evaporation crystallization were compared.From the economic point of view,vacuum evaporation crystallization was adopted to produce high-purity calcium formate with larger particle size and achieve high economic value.