Nitric Acid

Abstract

Nitric acid is a strong acid, a powerful oxidizing compound, and a nitrating agent. These properties make it an important basic chemical compound that is used in the production of many important chemicals such as fertilizers, polyurethanes, organic chemical intermediates, pharmaceuticals, synthetic fibers, dyes, insecticides, fungicides, and explosives. Nitric acid is produced through the oxidation of ammonia to nitrogen oxides, which are then absorbed by water to produce nitric acid. Weak nitric acid processes produce nitric acid in the concentration range of 50–65 wt %. The two main types of weak acid process are the monopressure process and the dual‐pressure process. The monopressure process operates at either moderate (0.3–0.6 MPa) or high pressure (0.7–1.2 MPa). The dual‐pressure process performs the conversion of ammonia at atmospheric or moderate pressures (0.3–0.6 MPa) and the absorption of nitrogen oxides at high pressure (1.1–1.5 MPa). Nitrogen oxides in the tail gas leaving the process are reduced to below environmental regulatory limits by either extended absorption or catalytic abatement. Strong nitric acid of 98–99 wt % is produced by either extractive distillation or direct strong nitric acid process. The extractive distillation process uses either magnesium nitrate or sulfuric acid as a dehydrating agent to surpass the maximum boiling azeotrope of nitric acid. The direct strong nitric acid process is similar to the weak nitric acid process, but has additional processing steps that bypass the azeotrope to produce strong nitric acid. Information on the chemical and physical properties, manufacturing processes, materials of construction, uses, safety and health, analytical methods, and process licensors of nitric acid is included.

High Pressure Raman Spectroscopy of Nitric Acid

“…It is known that the molecule of pure nitric acid is planar under room conditions with a C S symmetry. According to Stern et al 4 and Luzzati et al, 20 the structure is monoclinic. Luzzati suggests that twinning and disordering occur in the crystal owing to the position of the hydrogen atoms.…”

“…peaks decreases with increasing concentration of water, in agreement with the equilibrium of reaction 1 and the literature. 4,15,19 Depending on the water concentration, the appearance of the ν 1 NO 3…”

“…The concentrated acid is especially known to react explosively with compounds such as ethanol, and its oxidizing properties have been used for military and aerospace applications. 4 Nitric acid does not seem to be an explosive compound by itself, but, associated with specific compounds, it is used as a powerful propellant. Actually, the chemical mechanism of nitric acid based monergols and propergols is not confidently established, and detonation effects can occur depending on concentration, temperature, pressure, and nature of the mixtures.…”

Pressure and Temperature Study of Nitric Acid by Raman Spectroscopy.

“…The measurements have been performed in pure (fresh distilled compound by CEA Le Ripault, France) and hydrated commercial (Prolabo-France) product. Table 1 gives the thermophysical properties of nitric acid and its hydrates [6].…”

Extraction of Copper and Zinc from Waste Printed Circuit Boards

“…Although nitric acid is well-known for its strong oxidizing power [27], we studied its efficiency for the extraction of Cu and Zn, and the co-extraction of other metals from powdered WPCBs at ambient temperature ( Figure 6). It was observed that the extraction efficiency of Cu increased slowly with respect to increasing concentration from 1.0 to 3.5 M. A further increase in the concentration to 4.0 M did not have much effect on the extraction efficiency.…”