XXXI.—The action of sulphur dioxide on metal oxides. Part 1

Hammick, Dalziel Llewellyn

doi:10.1039/ct9171100379

Cited by 11 publications

(7 citation statements)

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“…The manganese dioxide used had a chemical composition corresponding to MnO1.88. The fractional conversion based on weight gain data was then calculated by means of the relationship X = (13) Some typical fractional conversion vs. time curves are shown in Figure 2. According to Bureau of Mines (2) x-ray analysis of their spent MnsOa after absorption in a simulated flue gas, MnS04 was the only product.…”

Section: Resultsmentioning

confidence: 99%

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Kinetic studies of sulfur dioxide absorption by manganese dioxide

Kiang¹,

Li²,

Rothfus³

1976

Environ. Sci. Technol.

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Absorption of sulfur dioxide from s 0 2 -N~ mixtures by manganese dioxide was studied a t temperatures from 573 to 723 K, with SO2 concentrations from 0.2 to 1 vol % and pellets of manganese dioxide 5/16 in. (7.94 mm), 3/8 in. (9.52 mm), and 7 /~~ in. (11.11 mm) in diameter. The absorption rate, the total pore volume, and the specific surface area of a reacted pellet all decreased with fractional conversion of oxide to sulfate. The maximum conversion observed was always less than 60%. Microscopic examinations of reacted pellets indicated that reaction was nontopochemical a t the temperatures studied. A model was proposed to describe the reaction kinetics, assuming the manganese dioxide pellet to consist of porous particles whose size remains unchanged during reaction. Equations were derived to relate the particle porosity and the specific surface area of a reacted pellet to conversion. The reaction was assumed to be irreversible and first order with respect to SO2 concentration and also proportional to the reacting surface area. The agreement between the model and experimental data was satisfactory. An activation energy of 10.3 f 0.8 kcal/g mol (4.3 f 0.3 X lo7 J/kg mol) was obtained.

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Section: Resultsmentioning

confidence: 99%

“…Chem., 193,265-75 (1951). (13) Smith, K. L., Jr., Hessler, R. R., Science, 184,72- 3 (1974). (11) Isaacs, J. D., Schwarzlose, R. A., ibid., 233,85-91 (1975).…”

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confidence: 99%

Kinetic studies of sulfur dioxide absorption by manganese dioxide

Kiang¹,

Li²,

Rothfus³

1976

Environ. Sci. Technol.

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“…Thermodynamic data [12] for reactions 30, 31 and 32 show that these are all endothermic in accord with the evidence from DTA experiments. This thermodynamic data also showed that the reactions between iron oxides and sulphur dioxide were exothermic and further evidence [13] showed that a temperature of 700-800 ~ was required for sulphur dioxide to react slowly with iron(III) oxide. indicates phase definitely present fl indicates phase probably present 11"…”

Section: (C) Iron(ill) Oxide -Niekel(ii) Sulphide Mixturesmentioning

confidence: 86%

Solid state reactions between nickel(II) sulphide and oxides of manganese and iron

Gladman

Buttler

1975

Journal of Thermal Analysis

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Thermogravimetry and differential thermal analysis have shown that, when nickel(II) sulphide and manganese or iron oxides are heated together, several reactions occur depending on the molar ratio of the reactants. Detailed examinations of these reactions have shown that there are a number of intermediate stages, including the formation of sulphates.Previous workers [1] have shown that, on heating, manganese(II) sulphide reacts with oxides of manganese to give overall reactions of the type SOLID + SOLID ~ SOLID + GAS Using the basic techniques of thermogravimetry, differential thermal analysis, X-ray powder diffraction and chemical analysis, it has been possible to elucidate the reactions occurring when nickel(II) sulphide and oxides of manganese or iron are heated together, and by taking samples from the mixtures during the reactions, to study the reaction mechanisms involved. This was prepared by heating MnSO4 9 4H20 in air at 800 ~ for 12 hours, washing the residue with water until free from sulphate and then drying. The sample contained 99.5 % Mn20 a and had the partrigetite structure. Experimental Reactants

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“…In the completely anhydrous state it reacts in a complex fashion to form Mn,O, and Mn,O, in addition to MnSO, (17). The trioxide (18) can also form manganese sulfate : higher temperatures employed in this study.…”

Section: X-ray Powder Diffraction Analysismentioning

confidence: 96%