Iron pyrites carbon

Potential Processes. Sulfur vapor reacts with other hydrocarbon gases, such as acetjiene [74-86-2] (94) or ethylene [74-85-1] (95), to form carbon disulfide. Higher hydrocarbons can produce mercaptan, sulfide, and thiophene intermediates along with carbon disulfide, and the quantity of intermediates increases if insufficient sulfur is added (96). Light gas oil was reported to be successflil on a semiworks scale (97). In the reaction with hydrocarbons or carbon, pyrites can be the sulfur source. With methane and iron pyrite the reaction products are carbon disulfide, hydrogen sulfide, and iron or iron sulfide. Pyrite can be reduced with carbon monoxide to produce carbon disulfide. 

Siilfuric acid from iron pyrites Paint pigments roasting of metallic oxides Refractory clays calcination of refractory clay to reduce shrinkage Foundry sand removal of carbon from used foundry sand Fullers earth calcination of fuller s-earth material... 

Beyond these two columns, the removal of all valence electrons is usually not energetically possible. For example, iron has eight valence electrons but forms only two stable cations, Fe and Fe. Compounds of iron containing these ions are abundant in the Earth s crust. Pyrite (FeS2) and iron(II) carbonate (FeC03, or siderite) are examples of Fe salts. Iron(IIt) oxide (Fc2 O3, or hematite) can be viewed as a network of Fe cations and O anions. One of the most abundant iron ores, magnetite, has the chemical formula FC3 O4 and contains a 2 1 ratio of Fe and Fe cations. The formula of magnetite can also be written as FeO FC2 O3 to emphasize the presence of two different cations. 

Brown iron ore is found both in amorphous masses, and in crystals of a variety of forme, according as the ore may have been produced either by the decomposition of iron pyrites, or substitution and oxidation of carbonate of iron. It also occurs in small rounded pieces, either loose or conglomerated, in which state it is known as pea iron ore. When mixed with clay and other earthy matters, and of a soft texture, in which state it is found in great beds, it is termed yellow oehre. It exists in great quantities in Normandy, Berry, Lorraine, Burgundy, and constitutes the principal supply of ore for many of the French ironworks. ... 

Ash, as determined by the standard test method (ASTM D-3174), is the residue remaining after burning the coal and coke and differs in composition from the original inorganic constituents present in the coal. Incineration causes an expulsion of all water, the loss of carbon dioxide from carbonates, the conversion of iron pyrites into ferric oxide, and other chemical reactions. In addition, the ash, as determined by this test method, will differ in amount from ash produced in furnace operations and other firing systems because incineration conditions influence the chemistry and amount of the ash. 

The results of leaching ground raw coals with HN03 alone are indicated in Table I. The sulfur content of the acid-leached coal is indicative of the organically bound sulfur, while the ash content reflects the removal of iron pyrite and other minerals such as carbonates which are soluble in nitric acid. It can be seen that acid leaching alone reduced the sulfur content of Cherokee coal by 57%,... 

In the laboratory ferric oxide may be obtained in a variety of ways. Thus when ferric hydroxide or sulphate is strongly heated ferric oxide remains behind, and the same applies if ferric chloride or sulphide, ferrous oxide or carbonate, or indeed the majority of ferrous salts,3 are heated in contact with air. Several of these methods are adopted on a manufacturing scale. For example, in the manufacture of sulphuric acid 4 iron pyrites is roasted in air, leaving a residue of ferric oxide. Thus —... 

Artificial pyrrhotite has also been obtained by passing hydrogen sulphide over heated ferrous chloride, air having been previously expelled by passage of carbon dioxide9 and by decomposing marcasite or iron pyrites with hydrogen sulphide at temperatures above 575° C.8 The reaction may be first detected at about this temperature and proceeds fairly rapidly at 665° C. The mineral is not a definite compound, but in all probability a solid solution of sulphur m iron sulphide.10... 

It is found in non-elemental form in sulfates (gypsum), in sulfidic ores (e.g. iron pyrites and copper, zinc, lead, nickel and cobalt sulfides) and in fossil fuels. In natural gas and crude oil it occurs bonded to both hydrogen and carbon and... 

Previous work has shown that ash-forming mineral matter, including iron pyrites, can be removed from coal by leaching the finely divided material with a hot caustic solution under pressure followed by washing with a dilute mineral acid (1-6). Recently, similar results have been achieved in leaching fine-size coal with hot sodium carbonate solutions (J7). In both cases, quartz appears to dissolve in the hot alkaline solution, while clay minerals and iron pyrite are converted into acid-soluble compounds which are removed in the acid washing step. Acid also removes any carbonate minerals which are present in the coal. 

It was further shown that iron pyrite reacts with hot alkaline solutions to form hematite and soluble sulfur species. Sodium hydroxide is considerably more effective than sodium carbonate for this reaction. However, the effectiveness of sodium carbonate solutions can be increased by increasing the treatment temperature and to a lesser extent by increasing the alkali concentration. The hematite produced is readily dissolved by hot mineral acids. 

The formation of reduced carbon can account for the qualitative features of the oxygen cycle. The fate of the reduced carbon in sediments is, however, coupled with the sulfur cycle, as described by Berner (1984) and Garrels and Lerman (1981). Some of the reduced carbon may be oxidized by bacteria under anoxic conditions with sulfate acting as the oxidizing agent. The carbon is fully oxidized to carbonate and the sulfur is reduced in several stages to a sulfide or to iron pyrite. The "stripped-down", balanced, chemist s redox equation is ... 

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