Manganese, 66-67 carbonate sulfide

Lead enters surface water from atmospheric fallout, run-off, or wastewater. Little lead is transferred from natural minerals or leached from soil. Pb ", the stable ionic species of lead, forms complexes of low solubility with major anions in the natural environment such as the hydroxide, carbonate, sulfide, and sulfate ions, which limit solubility. Organolead complexes are formed with humic materials, which maintain lead in a bound form even at low pH. Lead is effectively removed from the water column to the sediment by adsorption to organic matter and clay minerals, precipitation as insoluble salt (the carbonate, sulfate, or sulfide) and reaction with hydrous iron, aluminum, and manganese oxides. Lead does not appear to bioconcentrate significantly in fish but does in some shellfish such as mussels. When released to the atmosphere, lead will generally occur as particulate matter and will be subject to gravitational settling. Transformation to oxides and carbonates may also occur. 

Manganese dioxide and the salts manganese carbonate and manganese sulfide are poorly water-soluble, whereas the sulfate, chloride, nitrate and the permanganate ion... 

Magnesium carbonate Magnesium fluoride Magnesium hydroxide Magnesium phosphate Manganese(II) sulfide Mercury(I) chloride Mercury(II) sulfide Nickel(II) sulfide Silver bromide Silver carbonate Silver chloride Silver chromate Silver iodide Silver sulfate Silver sulfide Strontium carbonate Strontium sulfate Tin(II) sulfide Zinc sulfide... 

Aluminum hydroxide Barium carbonate Barium fluoride Barium sulfate Bismuth sulfide Cadmium sulfide Calcium carbonate Calcium fluoride Calcium hydroxide Calcium phosphate Chromium(III) hydroxide Cobah(U) sulfide Copper(I) bromide Copper(I) iodide CopperfU) hydroxide Copper(II) sulfide Iron(II) hydroxide Iron(III) hydroxide Iron(II) sulfide Lead(II) carbonate Lead(II) chloride Leadfll) chromate Lead(II) fluoride Lead(II) iodide Lead (II) sulfide Magnesium carbonate Magnesium hydroxide Manganese(II) sulfide Mercury(l) chloride Mercury(U) sulfide Nickel(II) sulfide Silver bromide Silver carbonate Silver chloride Silver iodide Silver sulfide Strontium carbonate Strontium sulfate Tin(II) sulfide Zinc hydroxide Zinc sulfide... 

Steam and natural waters. Titanium alloys are highly resistant to water, natural waters, and steam to temperatures in excess of 300°C. Excellent performance can be expected in high-purity water and fresh water. Titanium is relatively immime to microbiologically influenced corrosion (MIC). Typical contaminants found in natural water streams, such as iron and manganese oxides, sulfides, sulfates, carbonates, and chlorides do not compromise titanium s performance. Titanium remains totally unaffected by chlorination treatments used to control biofouling. 

The principal ores of zinc are sphalerite (sulfide), smithsonite (carbonate), calamine (silicate), and franklinite (zine, manganese, iron oxide). One method of zinc extraction involves roasting its ores to form the oxide and reducing the oxide with coal or carbon, with subsequent distillation of the metal. 

None of the natural sulfides of manganese are of any commercial importance. Some siUcates have been mined. Rhodonite and braunite are of iaterest because these are frequendy associated with the oxide and carbonate minerals. The chemical composition of some common manganese minerals are given ia Table 3. 

A few of the transition metals, including gold, platinum, and iridium, are found in nature as pure elements, but most of the others are found associated with either sulfur or oxygen. Iron, manganese, and the metals of Groups 3 to 6 (except for Mo) are most often found as oxides less often, they occur as sulfates or carbonates. Molybdenum and the metals of Groups 7 to 12 (e.xcept forMn and Fe) are most often found as sulfides. 

By far the most important ores of iron come from Precambrian banded iron formations (BIF), which are essentially chemical sediments of alternating siliceous and iron-rich bands. The most notable occurrences are those at Hamersley in Australia, Lake Superior in USA and Canada, Transvaal in South Africa, and Bihar and Karnataka in India. The important manganese deposits of the world are associated with sedimentary deposits the manganese nodules on the ocean floor are also chemically precipitated from solutions. Phosphorites, the main source of phosphates, are special types of sedimentary deposits formed under marine conditions. Bedded iron sulfide deposits are formed by sulfate reducing bacteria in sedimentary environments. Similarly uranium-vanadium in sandstone-type uranium deposits and stratiform lead and zinc concentrations associated with carbonate rocks owe their origin to syngenetic chemical precipitation. 

Carbon, activated Chlorates Calcium hypochlorite, all oxidizing agents, unsaturated oils Ammonium salts, acids, metal powders, sulfur, finely divided organic or combustible materials, cyanides, metal sulfides, manganese dioxide, sulfur dioxide, organic acids... 

Ostwald s step rule holds that a thermodynamically unstable mineral reacts over time to form a sequence of progressively more stable minerals (e.g., Morse and Casey, 1988 Steefel and Van Cappellen, 1990 Nordeng and Sibley, 1994). The step rule is observed to operate, especially at low temperature, in a number of min-eralogic systems, including the carbonates, silica polymorphs, iron and manganese oxides, iron sulfides, phosphates, clay minerals, and zeolites. 

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