Ammonium nitrate production routes: The vapor-phase neutralization of ammonia with nitric acid to form ammonium nitrate is commonly referred to as which named process?

Introduction:
Ammonium nitrate (AN) is produced by reacting ammonia with nitric acid. Industrially, this neutralization can be carried out in liquid or vapor phases. Named processes help distinguish operating regimes and equipment designs used in fertilizer manufacture.

Given Data / Assumptions:

• Reaction: NH3 + HNO3 → NH4NO3 (highly exothermic).
• Focus: vapor-phase neutralization terminology.
• Application: prill/granule production for fertilizers.

Concept / Approach:
The vapor-phase route, historically known as the Stengel process, feeds gaseous ammonia and nitric acid vapor (or mist) to achieve rapid neutralization and produce AN with controlled moisture content before concentration and finishing. Other names in the list denote unrelated processes: Haber for ammonia synthesis, Le Chatelier for equilibrium principle (not a process), DuPont as a company, and Ostwald for nitric acid production from ammonia oxidation—not AN neutralization.

Step-by-Step Solution:
Identify the target operation: vapor-phase NH3–HNO3 neutralization.Match to the correct named route: Stengel process.Exclude names associated with other chemistries (Haber, Ostwald, etc.).

Verification / Alternative check:
Fertilizer technology references distinguish liquid neutralizers from the Stengel vapor-phase method, emphasizing equipment differences and control of off-gases and moisture.

Why Other Options Are Wrong:

• Haber: Ammonia synthesis, not AN production.
• Le-Chatelier's: A principle, not a named AN process.
• DuPont's: A company; not a standard process name here.
• Ostwald: Nitric acid production, not the neutralization step.

Common Pitfalls:
Conflating the nitric acid (Ostwald) and ammonia (Haber) upstream processes with the downstream neutralization step that actually makes ammonium nitrate.

Final Answer:
Stengel