Soda and Potash

Georg Ernst Stahl distinguished between the natural and artificial alkalies (soda and potash) as early as 1702, and noted that certain... 

Although chemists had long suspected that the alkaline earths are metallic oxides, the true nature of soda and potash was not surmised before the early nineteenth century (28). Lavoisier believed that they might contain nitrogen ... 

G. E. Stahl distinguishes between the natural and the artificial alkali (soda and potash). 

Achieving low fusion temperatures was largely adventitious in the earliest times but over the many years empirical additions were discovered. Chief among these were iron oxide, silica and lime added individually and under the right circumstances. Although we know now, soda and potash from the fuel ashes mixing with the ore also played a significant role. 

From this point we can proliferate other additions in limited amounts which further depress the fusion temperature. Notable of these are lime, alumina, soda and potash. The limitation in amounts is shown by phase diagrams to the facts that, above a limit, fusion temperatures climb rapidly. For example, an addition of 20% lime to the sio2-70% FeO mixture will lower the fusion temperature to 1150 C but a further addition up to 40% will bring the fusion temperature to over 1400 C. 

Only with soda and potash, the depression of the fusion temperatures continues with increasing amounts. 

Alkalies, caustic soda, and potash manufacturing industries... 

An immediate fruit of this new way of identifying different substances was a rapid increase in the number of known salts, and indeed of new substances of every sort. Different alkaline earths were identified, and chemists discovered that there were two distinct caustic alkalis (soda and potash). New acids, new... 

Alkali Any water-soluble substance having basic (as opposed to acidic) properties. In a restricted sense it is applied to the hydroxides of ammonium, lithium, potassium and sodium. Examples include soda and potash. Alkali are widely used in glass production. 

Fused caustic soda and potash, particularly under the influence of pressure, attack iron readily.3... 

Although compounds of sodium and potassium were known in ancient times, it was not until Humphrey Davy s famous electrolytic experiments in 1807 on molten caustic soda and potash that the metals themselves were first isolated. Lithium was first recognized as an alkali metal in various silicate and mica minerals in 1817 (by ArfVedson, who thus named it from the Greek word for stone) and first isolated, again by Davy, in 1818. The discovery of cesium (1860) and rubidium (1861) had to await the development of atomic spectroscopy (by Bunsen and Kirchoff) their names reflect the colors of their dominant spectral lines (Latin caesius, sky blue, and rubidus, deep-red). 

He conjectured further that soda and potash were probably complex even Lavoisier had allowed as much. Beddoes concluded with the reflection Should the present view lead, in but a single instance, to successful experiments on the decomposition of bodies of unascertained constitution, it would be a great advance towards the removal of the present difficulties in chemical theory and practice. ... 

In recent years, a number of electrolytic processes have utilized membranes in producing both anodic and cathodic products. By far, however, the most important application of this technology has been in the chlor-alkali industry. Intense commercial and academic interest has been focused into this field during the past decade so that ion exchange theory as applied to membranes is in a more advanced state than any of the other ion exchange systems. The primary examples of industrial chlor-alkali electrochemistry are found in the production of chlorine, caustic soda and potash, hydrogen and hypochlorite (1) (4). 

That a difference existed between soda and potash was only gradually realised. In 1702 Stahl distinguished between natural and artificial alkalis, evidently referring to soda and potash, noting that salts of the former sometimes possessed a different crystalline form from the corresponding salts of the latter. In 1736 Duhamel de Monceau observed further differences between mineral alkali, that is soda, and vegetable alkali or potash,... 

Seaweeds are a well-known source of minerals and their levels depend on different seaweed genera. Formerly, brovm seaweed was used for the production of soda and potash and it has also been a source for iodine... 

In the next step of the calculation, we must remember that the alumina (29.30% from Table 6) is combined in three minerals— kaolinite, soda mica, and potash mica. Knowing now the percentage soda and potash micas, we can calculate from their formulae how much AI2O3 they contain. Subtracting this amount from the total AlgOg (29.30%), we can find how much AlgOg is present as kaolinite, and hence calculate the percentage of kaolinite. 

Soda and potash liberate carbon dioxide on treatment with acids - a further feature of the latter. 

Soda and potash, once made by leaching ashes with water, can be converted into the caustic varieties by treatment with milk of lime, a suspension of slaked lime. 

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