The Danger of Hydrofluoric Acid
Views: 0 Author: Site Editor Publish Time: 2024-01-08 Origin: Site
Hydrofluoric acid is a key chemical in many industries, particularly as a surface treatment agent (glass, metals, ceramics, etc.) or as a reaction additive. It is used in many fields of activity, from the production of photovoltaic cells to industrial maintenance in the food industry. Despite the dangers associated with its use, there are few or no substitute products or techniques. This is why its production is growing along with its global demand.
Like the hydrofluoric acid HF, the fluorides in acidic environment generate a dual action which is both:
corrosive because of the H+ ions of the acid;
and toxic because of the fluoride ions F- which, thanks to the destruction of the superficial layer of skin or eye, can penetrate deeply, chelate calcium and magnesium, and thus disrupt the biological balances. This results in very severe necrosis and in disruptions of the various turnovers.
The destructive action of the acid mainly targets the superficial layers, whereas the fluoride ion does not damage them that much[1]. Then the devastation of these layers allows the HF and the fluoride ions that HF progressively releases to penetrate and to spread into the deepest tissues, resulting in liquefactive necrosis. This specific mechanism differentiates HF from other acids and particularly from strong acids which cause coagulation necrosis with precipitation of the tissular proteins.
The HF hazard is due to the double presence of H+ and F- in an acidic medium. Any acid can release H+ into the medium – any fluoride can release F-
In the equilibrium HF <-> H+ + F-, the first entity to be consumed is H+.
The more acidic the medium is, the higher the concentration in acid (meaning the concentration in H+) will be in the mixture, and the more the fluoride ions will be released and the more they will be able to react (Le Chatelier' s Principle).
This is the reason why the chemical substances derived from hydrofluoric acid have a specific classification, with more strict regulations for very toxic products, because there is still a HF hazard even for low concentrations.
