Nitric Acid

Systems

Pfaudler offers different processes for nitric acid concentrations, depending on the required final concentration.
Medium Concentration of Nitric Acid using the Pfaudler MoNA® Process HNO3 forms an azeotropic mixture with water at a concentration of approx. 68% HNO3. Using the Pfaudler MoNA® process, weak nitric acid is concentrated up to this composition by rectification.

High Concentration of Nitric Acid

To break the azeotropic point for achieving concentrations up to 99 wt% nitric acid (HNO3), an extractive rectification is necessary.

Pfaudler offers two different processes for carrying out the rectification.

High Concentration of Nitric Acid using the Pfaudler HoN-SA® Process

Using the HoN-SA® process, 99% HNO3 can be obtained (even higher, upon clients request) thorugh extractive rectification using sulfuric acid as an extractive agent to break up the azeotrope and extract the water. The sulfuric acid is reconcentrated and internally recycled.

High Concentration of Nitric Acid using the Pfaudler HoN-MA® Process

Using the HoN-MA® process, 99% HNO3 can be obtained (even higher, upon clients request) through extractive rectification using magnesium nitrate as an extractive agent to break up the azeotrope and extract the water. The magnesium nitrate is reconcentrated and internally recycled.

Within both the processes, the extractive agent is reconcentrated and fed back to the HNO3 concentration column. This allows a closed loop without consumption of the agent.

In both process technologies, an additional off-gas treatment is part of the overall process design, which helps in achieving a yield of more than 99.5% nitric acid.