Salt, Sodium Chloride, Potassium Chloride

From earliest times on not only humans used rock salt to equalize the mineral balance of the body. For this purpose, also animals in the wilderness regularly visit salt deposits. Already rather early salt was artificially produced from salt springs or seawater. Salt was as valuable as gold. This can be derived from the fact that it became a rather precious commodity for which it was worth to accept the trouble and expenditures transporting it over long distances. The trade routes were called “Salt streets”. Both, the cities where salt was won and the owners of the salt production facilities obtained wealth and power. Today many city names still refer to the salt production: Salzburg, Bad Salzungen, Bad Reichenhall etc.  Beginning during the middle of the 19^th century, motivated through the work of Justus von Liebig, the mining production of potassium salt gained in significance, especially the production of mineral fertilizer.

The result was the search for salt cavities. Today there are extensive salt cavities known in Germany and also worldwide. Generally natural salt cavities develop by evaporation of ocean and fresh water in hot and dry (arid) climatic conditions. The in the water dissolved minerals crystallize during evaporation of the water in dependence of their solubility and deposit in layers on the ground. In this manner developed, for example approximately 250 million years ago, the domestic salt cavities through evaporation of a flat sea, the Zechsteinmeer, at which there were several cycles of evaporation and the afflux of fresh seawater. This caused that already deposited salts were partially dissolved again respectively recrystallized. Through this and often due to later tectonic influences, additional salt minerals were created, which were not present in the primary deposits. Similar processes were and are still occurring worldwide today.
The complex processes of the formation of salt cavities result in that from a few main elements like sodium, potassium, magnesium, calcium, chloride, sulphate and water, numerous salt minerals can be created. The most important are:

Almost 20 additional salt minerals like langbeinite, schönite, bischofite, leonite etc. can occur in the evaporates. They form the evaporates in the most different mineral compositions, from pure rock salt to the simultaneous combination of eight and more salt minerals.

A very elegant method for the determination of the mineral composition is the X-ray powder diffraction.
The K-UTEC AG Salt Technologies located in Sonderhausen/Germany, which possess a more than 50 year treasure trove of experiences in research of salt mining and processing, conducts such analyses on a large scale. The mineral composition is determined with the assistance of an X-ray Powder Diffractometer  “D2 Phaser from Bruker AXS” in Karlsruhe/Germany by analysing characteristic X-ray diagrams, as well as with the assistance microscopic procedures. The chemical analysis provides the element content from which the quantities of the minerals contained can be calculated.

• Comminuted with the Variable Speed Rotor Mill PULVERISETTE 14 classic line using a des 0.08 mm sieve
• Measured with the Laser Particle Sizer ANALYSETTE 22 MicroTec plus

The determination of the qualitative and quantitative mineral composition via the classic method is very elaborate. With the introduced method, in comparatively brief time it is possible to analyse the samples in regard to quality and in broad limits in regards to quantity. For small mineral contents below 1 % which can definitely be a decisive factor for the production, often only the classic evaluation with a microscope remains. The largest source of mistakes is the inhomogeneity of the cavities and unavoidable mistake during sampling. In this regard are the unavoidable mistakes during the sample preparation and the quantitative evaluation of the X-ray crystallography are relativized.