A simplified process for the extractive distillation of nitric acid

Abstract

A simple process for the concentration of aqueous nitric acid has been demonstrated in pilot plant operation as part of the Consolidated Fuel Reprocessing Program at the Oak Ridge National Laboratory. A mathematical model of this process shows reasonable agreement with important experimental data. This extractive distillation process utilizes an aqueous solution of magnesium nitrate as the solvent and is a simplified version of that used commercially. The process features two vessels for the distillation and solvent recovery operations. The acid feed and product compositions and flow rates were determined with reasonable certainty. The internal process flow rates and compositions of the boiling solutions in the distillation and solvent recovery vessels could not be determined with as much certainty. The development and use of a process model provides greater insight into the process than was available from the experimental data and also provides methods of process design and simulation.

Extractive Distillation Configuration for Nitric Acid Dehydration Using Sulfuric Acid as a Solvent

“…In the case of dehydration of nitric acid, magnesium nitrite and sulfuric acid are proposed as extracting agents for extractive distillation in the literature. , Vailiancourt commented that magnesium nitrate is a less efficient extractive entrainer than sulfuric acid as it requires a higher number of stages and reflux ratio, which ultimately leads to a higher energy consumption and quantity of entrainer to achieve the same separation. The feasibility of using sulfuric acid to dehydrate spent nitric acid has already been reported .…”