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Minerals of base metals
Published in Francis P. Gudyanga, Minerals in Africa, 2020
Sphalerite (Zn, Fe)S is the major commercial source of zinc metal [715]. Other sources of zinc are smithsonite (zinc carbonate), hemimorphite (zinc silicate), wurtzite (another zinc sulphide), and sometimes hydrozincate (basic zinc carbonate). Sphalerite consists largely of zinc sulphide with variable amounts of iron. Associated with it are minerals galena PbS, pyrite FeS2 and other sulphides as well as calcite CaCO3, dolomite CaMg(CO3)2, and fluorite CaF2. As a chalcophile, zinc has low affinity for oxides and prefers to bond with sulphides.
Occurrence and Production
Published in Frank Porter, Zinc Handbook, 1991
Some credit India with developing the first knowledge of true zinc smelting while others attribute its discovery to the Chinese. The production of metallic zinc certainly occurred much later than other common metals. Copper was smelted from its ores around 5000 B.C., lead about 4000 B.C. and iron about 2000 B.C., but zinc does not seem to have been available on a commercial scale until the 14th century A.D. although small quantities of metallic zinc were occasionally recovered from the flues of lead-smelting furnaces. Professor Li is quoted by Dawkins (1956) as suggesting that the development of zinc in China may be divided roughly into four periods distinguishable as follows: 1st-7th century-Zinc contained in articles was probably introduced from impure lead.7 th-10th century − Brass is made from zinc ore (smithsonite ZnCO3 ) and used for ornaments of which zinc is the chief component, but the Chinese did not know about metallic zinc at that time.10th-14th century-The zinc ore is mixed with copper to make brass coins, but the Chinese still did not know how to isolate zinc metal.From ca. A.D. 1450 - Zinc and brass are prepared from smithsonite; and metallic zinc is used for making coins and other articles.
Spectroscopic Methods
Published in Michael Dornbusch, Corrosion Analysis, 2018
Zinc surfaces have a low corrosion rate caused by the stable carbonate/ hydroxide passive layers broadening the passive range of the metal (compare Chap. 1.1.1). On corroded zinc surfaces in CO2 containing atmosphere and chloride containing electrolytes (sea water) often formed besides ZnO and Zn(OH)2 $ {\text{Zn(OH)}}_{ 2} $ complex compounds like Zn5(OH)8C12 $ {\text{Zn}}_{ 5} ( {\text{OH)}}_{ 8} {\text{C1}}_{ 2} $ (simonkolleite), ZnCO3 $ {\text{ZnCO}}_{ 3} $ (smithsonite) and Zn5(OH)6(CO3)2 $ {\text{Zn}}_{ 5} ( {\text{OH)}}_{6} ( {\text{CO}}_{ 3} )_{ 2} $ (hydrozincite) [80, 81]. The corresponding spectroscopic data of the corrosion products are summarized in Table 5.6 in the app. (for Raman data see also Ex. 3.15). Therefore carbonate based conversion layers on zinc and aluminium have been tried to precipitate on the surface to increase the corrosion protective performance of the surface. The zinc coated steel has been immersed into a carbon dioxide saturated solution at pH = 5 for 15 minutes (Fig. 3.46) and for the aluminium surface sodium fluoride has been added to the carbonate solution at pH = 3 for 15 minutes (Fig. 3.47). As already mentioned the samples have been sanded before the measurements to use the IRRAS methods to investigate the spectra.
James Smithson on the Calamines: Chemical Combination in Crystals
Published in Ambix, 2018
In recognition of Smithson’s contribution, the non-hydrous carbonate of zinc was subsequently named “smithsonite.” The name was proposed in 1832 by Haüy’s student and successor in the chair of mineralogy and geology at the Faculté des sciences in Paris, François Sulpice Beudant (1787–1850).64 The silicated zinc compound Smithson studied (the “electric” calamine) has since become known as “hemimorphite.” The name was proposed by the German mineralogist Adolph Kenngott (1818–1897) in 1853. Kenngott acknowledged that the property of hemimorphism was shared by other minerals, but he believed that using the name to signify this particular substance might encourage the identification of other stones with similar crystallography. To describe Smithson’s hydrated zinc carbonate Kenngott proposed the name “hydrozincite,” which is still used by mineralogists.65