Manganese-calcium carbonate decomposition

In the molten charge, silicon, phosphorus, sulfur, manganese, and carbon are converted to the corresponding oxides by reaction with iron oxide (Fe203). Oxides of carbon and sulfur pass off as gases, while the oxides of phosphorus and silicon combine with calcium oxide (formed by the decomposition of the limestone) to form phosphates and silicates ... 

Fte mUton.—Carbon monoxide can he prepared in -various ways. (1) It is formed when moo oxide, ferric oxide manganese dioxide, and many other oxides are heated with charcoal it is also formed -when chalk (calcium carbonate) and other carbonates are heated with metallic zinc or iron fiUngs the decomposition which takes place in these cases is represented by the following... 

Erdey and Paulik (100), in a simultaneous DTA-TG study, investigated the thermal decomposition of barium, strontium, manganese(II), calcium, magnesium, and zinc oxalates in air and nitrogen atmospheres. It was found that the evolved carbon dioxide formed in the reaction played an important part in that it may inhibit the progress of the reaction and shift the peak temperatures to higher values. 

The first reaction predominates if the product contains a large amount of water (-18%). This reaction is analogous to the disproportionation of aqueous hypochlorite. However, disproportionation is much slower in solid calcium hypochlorite than in solution. Under dry conditions, the second reaction predominates. It is catalyzed by transition metals including iron and manganese. It may occur explosively 150°C. Thus, calcium hypochlorite products usually contain some water or an additive such as magnesium sulfate heptahydrate. The third reaction is the reverse of chlorination. The fourth reaction is due to the adsorption of carbon dioxide from air or the release of carbon dioxide from carbonate salt impurities. It is accelerated by water and temperature. The first reaction accounts for -70%, and the second reaction -30%, of the decomposition of solid calcium hypochlorite made in the United States and stored in sealed containers at 25°C. ... 

Handling, Storage, and Precautions in solid form, this reagent is rather unstable. It sometimes undergoes spontaneous decomposition which occasionally results in a violent explosion attributed to impurities such as chloride ion, manganese dioxide, or nitrite ion. Stored in a desiccator over calcium oxide in the presence of ammonium carbonate to provide an ammoniacal atmosphere, it is stable for several months. 

Synthetic routes derived from molecular and non-molecular precursors have expedited the development of technologically important 2- and 3- dimensional materials. Such approaches have often proved superior to conventional ceramic techniques in that high purity bulk samples or thin films can be prepared at lower temperatures much more rapidly. Predominant among the precursor methods are those based on decomposition reactions. These either involve gaseous species, such as those used in chemical vapor deposition (CVD), or solids. Examples include the pyrolysis of the gas-phase precursor [(CH3)2A1(NH2)]3 to produce aluminum nitride (i) and the thermal decomposition of solid state carbonate precursors of calcium and manganese (Cai j,Mn C03, 0 < x < 1) to produce several of the known ternary compounds in the Ca-Mn-O system (2). Single-displacement reactions are also common as precursor methods. These approaches usually involve gas-phase reactions and are also used in CVD techniques. Examples here include the formation oi... 

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