Electrochemistry and Reactions in Molten Li[sub 2]SO[sub 4]-Na[sub 2]SO[sub 4]-K[sub 2]SO[sub 4]

Johnson, Keith E.; Laitinen, Herbert A.

doi:10.1149/1.2425739

Cited by 52 publications

(16 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…followed by the chemical combination reaction SOs-+ SO~-: S~062- [4] or followed by a further electrochemical reaction…”

Section: Resultsmentioning

confidence: 99%

“…Reaction [4] must be very slow; otherwise a cec mechanism would be observed instead of ace mechanism. Shores and Fang These reduction products were suggested without experimental substantiation, and apparently Eq.…”

Section: So8-+ E-: Soa 2-[5]mentioning

confidence: 99%

“…Liu (3) found sulfite and and the detection of SO2, the following parallel oxisulfide but little or no sulfur in the cathode comdationreactions for sulfate ions are proposed partment of a Li2SO4-KsSO4 melt electrolyzed be-8042------803 ~-~2 0'2 4-2e- [19] tween platinum electrodes at 625~ Johnson and Laitinen (4) reported that a eutectic LizSO4-NasSO4-KsSO4 58042-_--850162-+ 2 O2 + 4-6e- [20] melt at 550~ formed either sulfur or a metallic sulfide. 128042-----2.880192-4-5 O3--4-15e- [21] The present results show that at E = --2.0V with respect to a Ag/Ag+ reference .electrode, the products re-202-----O3-4-3e- [22] sulting from the cathodic reduction of sulfate ions are sulfide and peroxide with no sulfur or sulfite formaand a Pt or PtO3 dissolution reaction tion; this agrees partially with the previous results Pt 4-8 O~-----PtO6 s-4-5 O3 [23] from Liu and from Johnson and Laitinen.…”

Section: ~mentioning

confidence: 99%

See 2 more Smart Citations

Electrochemical Reactions in a Pure Na2 SO 4 Melt

Fang

Rapp

1983

J. Electrochem. Soc.

View full text Add to dashboard Cite

Cyclic voltammetry and chronopotentiometry were used to study the electrochemical reduction reactions of SO3 gas, Oz-and SO4 s-ions in a Na~SO4 melt at 900~ The reduction reaction of SO~ follows a ce mechanism: SO3 first reacts chemically with SO42-to form $2072-and then proceeds via a one-electron electrochemical reduction reaction to form SO3-. The reduction of peroxide 02-ions forms either O s-or both O 2-and superoxide O2 z-ions. Sulfate ions are subjected to decomposition at either very positive or very negative potentials. At very high positive potentials, sulfate ions decompose to evolve SOs and 02 gases, in addition superoxide ions are also formed. At very negative potentials, sulfate ions decompose to form sulfide and peroxide.In general, the attack of metals by a salt film in an oxidizing gas, which is called "hot corrosion" (1), becomes virulent only when the salt is molten. In this circumstance the alloy is physically separated from the gas phase by the molten salt so that the mechanism of corrosion must involve mainly electrochemical reactions. Obviously, an electrochemical study should be the most promising approach to investigate hot corrosion and might eventually explain the reaction mechanisms.Electrochemical studies have been confined mostly to alkali halide melts where a voluminous literature can be found(2). Sulfate melts, on the other hand, have received little study because of their limited practical importance except for their deleterious effect in the hot corrosion of metals. Na2SO4, because of its high thermodynamic stability, is the constituent most commonly found in the salt film deposited by the combustion of fossil fuels; knowledge about the electrochemical reactions taking place in this melt is essential to the understanding of the Na2SO4-induced hot corrosion mechanism. Electrochemical reduction of SO42-ions has been studied by several investigators. Liu (3) found sulfite and sulfide, but little or no sulfur, as the reduction products of a LisSO4-K2SO4 melt electrolyzed between platinum electrodes a~ 625~ Johnson and Laitinen (4) however reported that a eutectic Li~SO4-Na2SO4-KsSO4 melt electrolyzed at 550~ formed either sulfur or a metallic sulfide. In prolonged cathodic electrolysis of a LiSO4-K2SO4 melt at 625~ Burrows and Hills (5) observed the formation of elementary sulfur, oxide ions, and SOs. Reduction reactions for the dissolved gaseous species O2, SOs, and SO3 in the Li~SO4-K2SO4 eutectic melt were studied using cyclic voltammetry by Burrows and Hills (5). They found no cathodic reduction of dissolved oxygen but there were reduction waves for dissolved SO3 and SO2; nonetheless, no reduction reaction mechanism for SO3 and SO2 was given. Shores and Fang (6) suggested that the reduction of SO3 in a pure Na2SO4 melt at 900~ actually proceeded through the reduction of the pyrosulfate ion (S2OT ~-) which was the reaction product from reacting SO3 with SO42-. The present study concerns the electrochemical reactions of dissolved SOs, oxide ions, and sulfate ions (SO42-) in a pure ...

show abstract

“…followed by the chemical combination reaction SOs-+ SO~-: S~062- [4] or followed by a further electrochemical reaction…”

Section: Resultsmentioning

confidence: 99%

Section: So8-+ E-: Soa 2-[5]mentioning

confidence: 99%

Section: ~mentioning

confidence: 99%

See 1 more Smart Citation

Electrochemical Reactions in a Pure Na2 SO 4 Melt

Fang

Rapp

1983

J. Electrochem. Soc.

View full text Add to dashboard Cite

show abstract

“…In sulfate melts like that of Townley, removal via an oxide mechanism has been shown by other authors (Salzano and Newman, 1972;Park and Rapp, 1986;Johnson and Laitinen, 1963). The mechanism proposed by these authors was simpler than that of the pyrosulfate system; generally a "direct" reduction of SO, was observed, considered to be due to an oxide mechanism.…”

Section: ( 2 )mentioning

confidence: 85%

Electrochemical membrane flue‐gas desulfurization: K₂SO₄/V₂O₅ electrolyte

Schmidt

Winnick

1998

AIChE Journal

View full text Add to dashboard Cite

show abstract

“…Electrochemical measurements were first reported by Liang, Bowen, and E l l i~t t ,~ using a reference electrode which operates at a sodium oxide activity fixed by the reaction 1/2W(s) + NazS(s) + '/202(g) = 1/~WS2(s) + NazO (6) inside a @-alumina membrane. Electrochemical measurements were first reported by Liang, Bowen, and E l l i~t t ,~ using a reference electrode which operates at a sodium oxide activity fixed by the reaction 1/2W(s) + NazS(s) + '/202(g) = 1/~WS2(s) + NazO (6) inside a @-alumina membrane.…”

Section: Potentiometric Studies (I) Oxide Activity In Purementioning

confidence: 99%

Studies of the sodium oxide-sodium sulfate system

Stern¹,

Deanhardt²,

Panayappan³

1979

J. Phys. Chem.

View full text Add to dashboard Cite

6) The small term (0.04 f 0.16) (DN/kJ mot') has been neglected inside the square brackets. Similarly negligible dependencies on the donor properties of the solvents were obtalned also for azide, tetraphenyiborate, and thiocyanate anlons, besides chloride. Only for bromide and i d i e are the coefficients of (DN/W mol-') comparable with the standard error: 0.13 * 0.17 and -0.17 f 0.08, respectively.(The original definitions of E, and DN are in terms of kcai mol-'; 1 cal = 4.184 J.) (7) A. Publication costs assisted by the Naval Research LaboratoryThe behavior of Na20-Na2S04 melts at 920 "C has been studied by four techniques; (1) chemical analysis of quenched melts, (2) manometric experiments in which the reversible uptake of O2 by the melts was observed,(3) potentiometric studies, using oxide ion specific zirconia electrodes, and (4) voltammetry, which detects the number of oxidizable species. In oxygen atmospheres all four studies are consistent with peroxide formation in the melt, although values of the peroxide/oxide ratio vary somewhat with method. At low O2 pressures (<0.1%), the potentiometric results are anomalous. 02,16Two prominent anodic waves were observed when Na20 was added to the melt; the first (wave I) occurred at --LO6 V vs. the Ag/Ag2S04 reference electrode and the second (wave 11) at --0.07 V. A third anodic wave appeared as a shoulder of anodic wave I1 at --0.49 V.This shoulder disappeared when the oxygen pressure above the melt was increased, as shown in Figure 7. Even though the shoulder was not positively identified, it is probably due to some oxidizable impurity in Na20.for curves A, B, and C, respectively. 02-+ 202 = 202-

show abstract

Electrochemistry and Reactions in Molten Li[sub 2]SO[sub 4]-Na[sub 2]SO[sub 4]-K[sub 2]SO[sub 4]

Cited by 52 publications

References 11 publications

Electrochemical Reactions in a Pure Na2 SO 4 Melt

Electrochemical Reactions in a Pure Na2 SO 4 Melt

Electrochemical membrane flue‐gas desulfurization: K₂SO₄/V₂O₅ electrolyte

Studies of the sodium oxide-sodium sulfate system

Contact Info

Product

Resources

About

Electrochemistry and Reactions in Molten Li[sub 2]SO[sub 4]-Na[sub 2]SO[sub 4]-K[sub 2]SO[sub 4]

Cited by 52 publications

References 11 publications

Electrochemical Reactions in a Pure Na2 SO 4 Melt

Electrochemical Reactions in a Pure Na2 SO 4 Melt

Electrochemical membrane flue‐gas desulfurization: K2SO4/V2O5 electrolyte

Studies of the sodium oxide-sodium sulfate system

Contact Info

Product

Resources

About

Electrochemical membrane flue‐gas desulfurization: K₂SO₄/V₂O₅ electrolyte