Simulation of chemical phenomena in the Co(NO3)2–Na2CO3–H2O system based on a thermodynamic model

Mostafa, M. G.; Matsumoto, A.; Wase, Kuniomi; Kishi, Yosuke

doi:10.1016/s0304-386x(00)00096-7

Cited by 5 publications

(6 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…From a critical review of the literature combined with an experimental study, efficient precipitation of cobalt can be obtained at pH > 9.0, with a residual aqueous cobalt concentration (< 0.015 ppm at pH = 10) complying with drinking water regulations (1 ppm) 47. The simulated solubility limit suggests the formation of a mixed cobalt hydroxy‐carbonate phase rather than a simple hydroxide or a carbonate solid, as previously pointed out 44, 45. Soluble hydroxide and carbonate complexes might not be stable in solution, thus limiting the solubility of the mixed precipitate.…”

Section: Resultssupporting

confidence: 60%

“…Data set 1: 3CoCO 3 . 4Co(OH) 2(s) from Mostafa et al45; all soluble species from Table 2 taken into account. Data set 2 : Co(OH) 2(s) from Smith and Martell31; all soluble species from Table 2 taken into account.…”

Section: Resultsmentioning

confidence: 99%

“…Data set 1: 3CoCO 3 . 4Co(OH) 2(s) from Mostafa et al45. OLI Systems Inc. ESP Process does not take into account C°CO

_{3}^{0}

, Co(HCO 3 ) + , Co 2 (OH) 3+ , Co 4 (OH)

_{4}^{4+}

, 3CoCO 3 .…”

Section: Resultsmentioning

confidence: 99%

“…The formation of the pure cobalt water‐free carbonate is expected to occur at temperatures above 160°C44 and hydroxy‐carbonates are preferentially formed at room temperature. However, solubility data for these compounds are severely limited: Only one reference could be found and this deals with an estimation of the solubility product of 3CoCO 3 .4Co(OH) 2 .6H 2 O, at ambient temperature 45. In the process of estimating K sp , the authors neglected the presence of the molecular form 3CoCO 3 .4Co(OH)

_{2}^{0}

in solution.…”

Section: Thermodynamic Modelsmentioning

confidence: 99%

See 3 more Smart Citations

Comparison of simulators for process and aqueous chemistry modeling

et al. 2005

View full text Add to dashboard Cite

Section: Resultssupporting

confidence: 60%

Section: Resultsmentioning

confidence: 99%

“…Data set 1: 3CoCO 3 . 4Co(OH) 2(s) from Mostafa et al45. OLI Systems Inc. ESP Process does not take into account C°CO

_{3}^{0}

, Co(HCO 3 ) + , Co 2 (OH) 3+ , Co 4 (OH)

_{4}^{4+}

, 3CoCO 3 .…”

Section: Resultsmentioning

confidence: 99%

_{2}^{0}

in solution.…”

Section: Thermodynamic Modelsmentioning

confidence: 99%

See 2 more Smart Citations

Comparison of simulators for process and aqueous chemistry modeling

et al. 2005

View full text Add to dashboard Cite

“…The narrow line of L-un, indicative of large crystallites, can be attributed to a cobalt hydroxy carbonate: Co(OH)(CO 3 ) 0.5 •0.11H 2 O [39]. The precipitation of mixed carbonate hydroxides is thermodynamically more likely than the precipitation of pure cobalt hydroxide, as was calculated by Mostafa et al [40]. For L-CNF, in addition to the graphitic lines, the three most intense diffraction lines of L-un, although somewhat broadened, are also observed.…”

Section: Investigation Of Dried Samplesmentioning

confidence: 73%

Preparation of Fischer–Tropsch cobalt catalysts supported on carbon nanofibers and silica using homogeneous deposition-precipitation

Bezemer

Radstake

Koot

et al. 2006

Journal of Catalysis

212

View full text Add to dashboard Cite

Homogeneous deposition-precipitation on either a silica or carbon nanofiber (CNF) support of cobalt from basic solution using ammonia evaporation was studied and compared with conventional deposition from an acidic solution using urea hydrolysis. In the low-pH experiment, the interaction between precipitate and silica was too high; cobalt hydrosilicates were formed requiring a reduction temperature of 600 • C, resulting in low cobalt dispersion. Lower interaction in experiments performed in a basic environment yielded a well-dispersed Co 3 O 4 phase on silica, and after reduction at only 500 • C, a catalyst with 13-nm cobalt particles was obtained. On CNF from an acidic solution, cobalt hydroxy carbonate precipitated and displayed a low interaction with the support resulting after reduction at 350 • C in a catalyst with 25-nm particles. From basic solution we obtained high dispersion of cobalt on the CNF, probably related to the greater ion adsorption. After drying, Co 3 O 4 crystallites were obtained that, after reduction at 350 • C, resulted in a catalyst with 8-nm Co particles. Samples prepared in the high-pH experiment had 2-4 times higher cobalt-specific activity in the Fischer-Tropsch reaction than their low-pH counterparts. CNF support materials combined with the high-pH deposition-precipitation technique hold considerable potential for cobalt-based Fischer-Tropsch catalysis.

show abstract