When does saltpetre appear?
the saltpetre can also appear as a result of rainwater infiltration or excessive humidity in a dwelling, due to poor ventilation, for example. * Capillarity, or capillary rise, refers to the migration of humidity in a wall in contact with damp ground.
Treatment anti-saltpetre: Fixer of salts hygroscopic When it is not possible to wait several months before the complete drying of the wallit is therefore advisable to use the treatment physical anti-saltpetre, the fixer of salts hygroscopic.
The first step is to vigorously rub the wall with a couch grass brush. Then wash with hot water containing Marseille soap or detergent. Rinse while making sure all whitish deposits are gone.
In France, the salt trade became a generalized royal monopoly throughout the kingdom in 1342 by Philip VI of Valois, partly to finance the expenses occasioned by the Hundred Years’ War. This monopoly makes it possible to collect a tax: the salt tax. The salt granaries are the most obvious manifestation of this policy.
Salt having become very cheap, its use has recently become abusive, causing an increase in the rate of cardiovascular diseases. For example, the French average is 9 g per day while the WHO recommendations recommend a maximum of 5 g.
Mining salt, like salt from salars, must nevertheless be purified to contain only sodium chloride for many uses, this is called refined salt. The largest salt factories in Europe today are located in Delfzijl at the mouth of the Ems in the Netherlands.
Sea salt is no longer produced except where production can be highly mechanized, such as on the coasts of the Mediterranean or for the production of luxury food salt. Many salt marshes have been converted into clear (refining basins) for oyster farming, into breeding basins (fish, shellfish).