What nitric acid concentration is considered concentrated nitric acid?
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As the title says. For the remaining 65% nitric acid at 80 degrees Celsius, is 316 stainless steel suitable? Is it a waste?
No relevant data was found, but there are several similar sets: 20% HNO3 + 3% HF at 25 degrees Celsius for 316 steel: 3.7 mm/a; 20% HNO3 + 3% HF at 50 degrees Celsius for 316 steel: 19.0 mm/a
I’ll also provide the group data: Nitric acid concentration: 70%, Temperature: boiling, Corrosion rate: 0.064–0.2 mm/a
This post was last edited by ship200 on 2009-9-3 at 09:16. The corrosion rate at 65% is less than 0.1 mm/a; at 70%, it is also less than 0.1 mm/a. At 65%, the corrosion rate at 90 degrees is less than 1 mm/a, but there is a tendency for intergranular corrosion. This information is based on Outokumpu’s corrosion data
According to the information I found, 65% nitric acid at 80 degrees Celsius can be used with 316 material, but it does not indicate that intergranular corrosion will occur. Intergranular corrosion mainly occurs when stainless steel is heated between 500 and 900 degrees Celsius, or for extended periods at lower temperatures; this leads to the formation of chromium-deficient regions at the grain boundaries, resulting in corrosion by nitric acid!
What concentration of nitric acid is considered concentrated nitric acid?
In general experiments, the nitric acid used is either below 1 mol/L or above 8 mol/L; concentrations within this range are not commonly used. Nitric acid with a concentration of 8 mol/L or higher is generally referred to as concentrated nitric acid. The mass fraction of concentrated nitric acid is generally around 68%
According to national standards, nitric acid with a concentration of over 97% (by mass) is considered concentrated nitric acid.
The concentration of concentrated nitric acid is generally not 97%. The typical percentage concentration as well as the molar concentration for concentrated nitric acid are 69.8% and 16 mol/L respectively
Please provide the specific sources for both 69.8% and 97%.
By **standard, nitric acid with a concentration of 68% or less is considered dilute nitric acid, while concentrated nitric acid typically has concentrations of 75% or 98%.