Calcite with manganese

Bodine, M. W., H. D. Holland, and M. Borcsik (1965), "Coprecipitation of Manganese and Strontium with Calcite. Symposium Problems of Postmagmatic Ore Deposition", Prague2, 401-406. 

Manganese Numerous investigations have been made of the coprecipitation of transition and heavy metals with calcite and aragonite. The two elements that have received the most attention are Mn2+ and Zn2+. This attention probably stems from their potential importance for studying diagenetic processes (e.g., Pingitore, 1978). 

Manganese appears to be capable of altering the apparent solubility behavior of calcite in deep sea sediments. This element has long been noted to be associated with calcium carbonate in deep sea sediments (e.g., Wangersky and Joensuu, 1964), and extensive experimental evidence exists for coprecipitation of Mn2+ with calcite (see Chapter 3). Both Pedersen and Price (1982) and Boyle (1983) have noted the close association of Mn with carbonate material in Panama Basin sediments. In fact, some of the pore waters approach equilibrium with MnC03,and mixed carbonate... 

Bodine M.W., Holland H.D. and Borcsik M. (1965) Coprecipitation of manganese and strontium with calcite. Symposium Problems of Postmagmatic Ore Deposition, Prague 2,401-406. 

Franklin M.L. and Morse J.W. (1983) The interaction of manganese(II) with the surface of calcite in dilute solutions and seawater. Mar. Chem. 12, 241-254. 

At about 4000 m water depth, carbonate tests are dissolved, because their solubility depends on pressure (this depth in the ocean is called calcite compensation depth, abbreviated CCD). With the dissolution of tests the metals collected before are again liberated and can contribute to the growth of manganese nodules. 

Mn(H20)p,] +, is the stable cationic form of manganese. The hydrated ion is pale rose-pink in color. Representative salts are Mn(N03)2 6H20, MnSO/7HoO, and MnCl2 4H20. These salts and the mineral rhodochrosite, MnCOg, are ail rose-pink or rose-red. Crystals of rhodochrosite are isomorphous with calcite (Chap. 8). 

The trace element content of late diagenetic calcite contrasts markedly with that of calcite formed early in diagenesis. Often these are relatively depleted in iron and magnesium and enriched in manganese (Lynch and Land, 1996 Milliken, 1998 Milliken et of., 1998). It is common for iron and magnesium to covary in late diagenetic calcite. The reason for this is unclear. 

The wave-lengths contained in table 1 complete the series of measurements of the K critical absorption of the chemical elements that we have been making in our X-ray laboratory during the past few years.3,4 We now have values of the K critical absorption wave-lengths for most of the chemical elements from manganese (atomic number 25) to uranium (atomic number 92) both inclusive. These wave-lengths have been measured by means of the same ionization spectrometer and with the same calcite crystal, and are therefore comparable with each other. 

Many experiments oti electrokinetic remediation are carried out on a laboratory or pilot plant scale, with artificially polluted clay media like kaolin. This is because clay soils usually contain a variety of other substances that are present in smaller or trace amounts, such as organic matter, iron oxides, quartz, feldspars, aluminum and manganese hydroxides, titanium oxides, carbonates, and calcite, which could affect electrokinetic response by decreasing the resistance to the flow of water through the sediment [10]. 

More then 150 minerals containing uranium are known. Typically, however, uranium ores contain only about 0.1% uranium. In the commercial production of uranium metal, the ore is crushed, concentrated, roasted, and in most cases leached with sulfuric acid in the presence of an oxidizing agent such as manganese dioxide or chlorate ions to convert all of the uranium to uranyl sulfato complexes. Carbonate leaching is used to extract uranium from ores containing minerals such as calcite. The recovery of uranium... 

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