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Originally Posted by Jim McDougall
... I admit I am still unclear on the differences in saltpeter, between sodium and potassium nitrates. It seems that both of these compounds are derived from bat guano. The only notable difference seems to be that the 'potassium' version is less 'hygroscopic' (susceptible to moisture effects) if I have understood correctly...
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Hopefuly Yulzari doesn't find all this a senseless bunch of words ...
Saltpetre refers to the combinations which form the multi-base nitrogenous acid, in particular the potassium and sodium hydroxides. More narrowly, the name saltpeter refers to potassium nitrate (KN03), and is reserved for sodium or saltpeter nitrate from Chile or Peru. Saltpeter was first cited by Geber in the 8th century, who called it salt petrae and the alchemists used the designation salt niter. This salt results from the decomposition of plant and animal organic matter and may, under favorable conditions, form efflorescences in certain soils, which should have attracted human attention in ancient times. Such efflorescences appear, in particular, in geographical areas characterized by abundant deposits of organic matter and where the climate is warm and with a prolonged and regular dry season, during which it is possible for such matter to decompose without being carried by water. the rains. The areas where the largest saltpeter deposits appear are India, Ceylon, Syria, Egypt, the Maghreb, South Africa, Peru, Bolivia, and Brazil, among others.
From the mid-nineteenth century a new method of saltpeter production was imposed: the conversion of nitro, that is, the production of potassium nitrate from sodium nitrate or saltpeter from Chile, imported mainly from that country. and from Peru. In this method, sodium nitrate and potassium chloride are reacted in aqueous solution at 90 ° C: NaN03 + KCI NaCl + KN03
THE NATURAL SALTPETER ...
This would be basically the following. We began by accommodating in casks layers of the earth from which the saltpeter was to extracted, alternated with those of ash, and sometimes with layers of straw added to facilitate the passage of water. A pit is dug into the upper part of this arrangement, where potash (our potassium carbonate) was added, and then water. After a while, the salt-laden water was allowed to flow (through taps or previously sealed holes) and evaporated in boilers. During the evaporation process, the mass of common salt (our sodium chloride) that was formed was removed with a slotted spoon until it had only the liquid. It was continued until complete evaporation, when finally there was the “raw or unclean” saltpeter, which would later be refined.
THE ARTIFICIAL SALTPETER ...
Saltpeter can also be obtained artificially through methods that humans have long mastered, as evidenced by Cristobal Rojas's in 1607. A traditional way of artificially obtaining potassium nitrate is to mix decomposing organic matter, such as nitrogen-rich stable waste, with plant ash (which contains a high percentage of potassium salts) and limestone. he difference would be that artificial saltirs were built by “the hands of men, and nitrate [was] ahi produced at the expense of human industry” 30. Equating the two ways of saltpeter formation, it would only be appropriate to decide on the most appropriate one. Couto, however, considers that the best way to “form” the saltpeter would be in the artificial salitaria, which, according to the author, “is no other thing but a palhaça house, under which certain amounts of land are gathered, that managed in a way are abundantly impregnated with potassium nitrate, or saltpeter. ”Couto goes on to explain how to build the salad boxes, in a wealth of detail that would make this article very extensive if we wanted to reproduce them. In any case, tanks should be built where the “salitifiable” materials should be deposited, which, properly treated, after a certain period would give the precious salt. But before moving on to the “recipe” itself, Couto says it is important for the “salitreiro” to know that: “potassium nitrate, this salt whose production and harvest is the object of its readings, is made up of three principles, oxygeneo, nitrogen, and potash: the combination of the first two constitutes nitric acid, and this later with potash said nitrate or saltpeter. Nitrogen could be obtained, as we have long known, from materials of animal and plant origin in which it could be found in large quantities. That is: “Generally all the lands called dung, […] the dark lands that are taken from the dark places, as under the houses, and above all there are livestock, wineries, horsemen […] are also good the dark lands underneath the treetops, […] the lands of the cemeteries, the farms, especially the sheep, the hens, doves, the corn fields, […] the mud of the villages, latrines, ponds, and alagoas…