Material selection for concentrated phosphoric acid reaction vessels
Thread Content
In the reaction vessel, concentrated phosphoric acid is used as a catalyst, with a concentration of 80–92%, and the temperature ranges from 0–50°C. What type of material is best for the reaction vessel – enamel or 316L? I’ve read some discussions on forums, but I’m still not quite sure
At room temperature, phosphoric acid, especially dilute phosphoric acid, has little corrosive effect on enamel and glass. However, concentrated phosphoric acid, when heated, reacts with SiO2 in glass or ceramics to produce silicon phosphate and water.
Therefore, 321 and 316 are used in phosphate production enterprises; other materials do not meet the requirements.
Okay, so what are the typical concentration and temperature ranges for which enamel is resistant to phosphoric acid? 316L should work as well, right? Does the 316 series work across the entire range of concentrations of concentrated phosphoric acid?
We used to produce phosphoric acid and polyphosphoric acid, and the material used for the arsenic removal reactors was 316L!