Sulfate calcium, oxidation results

Ramachandran and Smith obtained satisfactory agreement with experimental results on the reduction of nickel oxide with carbon monoxide (pore opening case) by considering the product layer diffusion coefficient as an adjustable parameter. Similarly, the model predicted pore closure and reaction die-off for the reaction of calcium oxide with sulfur dioxide, where the molar volume of calcium sulfate product is about three times that of the calcium oxide reactant. 

Catalysts active in the isomerization of n-butane have been synthesized by depositing sulfate ions on well-crystallized defective cubic structures based on ZrOz. This technique for introduction of sulfates does not result in any significant changes in the bulk properties of zirconium dioxide matrix. Active sulfated catalysts were prepared on the basis of cubic solid solutions of ZrOz with calcium oxide and on the basis of cubic anion-doped ZrOz. The dependence of the catalytic activity on the amount of calcium appeared to have a maximum corresponding to 10 mol.% Ca. Radical cations formed after adsorption of chlorobenzene on activated catalysts have been used as spin probes for detection of strong acceptor sites on the surface of the catalysts and estimation of their concentration. A good correlation has been observed between the presence of such sites on a catalyst surface and its activity in isomerization of n-butane. 

The results fiom these two types of data leads to our conclusion that the formation of CaO is a two step mechanism. The reduction of calcium sulfate to calcium sulfide (3) is the first step. By a consecutive reaction (4) the sulfur dioxide and the calcium oxide are formed. 

As a result of soil erosion, industrial and agricultural application, arsenic and it s compounds are widely distributed through the aquatic environment [16]. Arsenic can be removed from industrial waste by several methods before the waste is discharged into the water system. Some of the methods include precipitation by calcium oxide and ferric chloride, basic anion exchange resins, passage through lime and ashes, and flocculation with chlorine saturated water and ferrous sulfate [10]. 

Alkali metal haHdes can be volatile at incineration temperatures. Rapid quenching of volatile salts results in the formation of a submicrometer aerosol which must be removed or else exhaust stack opacity is likely to exceed allowed limits. Sulfates have low volatiHty and should end up in the ash. Alkaline earths also form basic oxides. Calcium is the most common and sulfates are formed ahead of haHdes. Calcium carbonate is not stable at incineration temperatures (see Calcium compounds). Transition metals are more likely to form an oxide ash. Iron (qv), for example, forms ferric oxide in preference to haHdes, sulfates, or carbonates. SiHca and alumina form complexes with the basic oxides, eg, alkaH metals, alkaline earths, and some transition-metal oxidation states, in the ash. 

In general, the chemistry of inorganic lead compounds is similar to that of the alkaline-earth elements. Thus the carbonate, nitrate, and sulfate of lead are isomorphous with the corresponding compounds of calcium, barium, and strontium. In addition, many inorganic lead compounds possess two or more crystalline forms having different properties. For example, the oxides and the sulfide of bivalent lead are frequendy colored as a result of their state of crystallisation. Pure, tetragonal a-PbO is red pure, orthorhombic P PbO is yeUow and crystals of lead sulfide, PbS, have a black, metallic luster. 

Other reactions taking place throughout the hardening period are substitution and addition reactions (29). Ferrite and sulfoferrite analogues of calcium monosulfoaluminate and ettringite form soHd solutions in which iron oxide substitutes continuously for the alumina. Reactions with the calcium sihcate hydrate result in the formation of additional substituted C—S—H gel at the expense of the crystalline aluminate, sulfate, and ferrite hydrate phases. 

Results For the St. Louis data, the target transformation analysis results for the fine fraction without July Uth and 5th are given in table 6. The presence of a motor vehicle source, a sulfur source, a soil or flyash source, a titanium source, and a zinc source are indicated. The sulfur, titanium and zinc factors were determined from the simple initial test vectors for those elements. The concentration of sulfur was not related to any other elements and represents a secondary sulfate aerosol resulting from the conversion of primary sulfur oxide emissions. Titanium was found to be associated with sulfur, calcium, iron, and barium. Rheingrover ( jt) identified the source of titanium as a paint-pigment factory located to the south of station 112. The zinc factor, associated with the elements chlorine, potassium, iron and lead, is attributed to refuse incinerator emissions. This factor could also represent particles from zinc and/or lead smelters, though a high chlorine concentration is usually associated with particles from refuse incinerators ( ). The sulfur concentration in the refined sulfate factor is consistent with that of ammonium sulfate. The calculated lead concentration in the motor vehicle factor of ten percent and a lead to bromine ratio of about 0.28 are typical of values reported in the literature (25). The concentration of lead in... 

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