Carbothermic smelting of aluminum

Stroup, P. T.

doi:10.1007/bf03397219

Cited by 9 publications

(8 citation statements)

References 4 publications

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“…The solubility of carbon in liquid A1 has been measured many times and most results [8][9][10][11][12] are essentially consistent with each other in the temperature range 1600-2600 °C. However, experimental measurements at lower temperatures show a large discrepancy.…”

Section: Experimental Information and Parameter Evaluationmentioning

confidence: 69%

“…Recently, Simensen [15] remeasured the solubility from 960 to 1000 °C and found that it changes from 6 ppm to 12.5 ppm accordingly, which agrees very well with the extrapolation from the data of Oden and McCune [12] at higher temperature. As a consequence, these data [15] together with all others [8][9][10][11][12] at higher temperatures were used in the present work in order to evaluate the properties of the liquid phase.…”

Section: Experimental Information and Parameter Evaluationmentioning

confidence: 99%

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Solubility of carbon in liquid Al and stability of Al4C3

Qiu

Metselaar

1994

Journal of Alloys and Compounds

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Using thermodynamic models the properties of the Al-C liquid phase have been evaluated from experimental information on the carbon solubility in liquid Al. After slight modification of the description of A14C3 presented by Gluschko and Gurvitch [1], the solubility has been described very well from 950 to 2500 °C with a regular solution model for the liquid phase. Stability of A14C3 was examined through thermodynamic calculations under various conditions. It has been shown that the description of A14C3 can account very well for most thermochemical measurements in a wide temperature range.

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Section: Experimental Information and Parameter Evaluationmentioning

confidence: 69%

Section: Experimental Information and Parameter Evaluationmentioning

confidence: 99%

Solubility of carbon in liquid Al and stability of Al4C3

Qiu

Metselaar

1994

Journal of Alloys and Compounds

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“…41 In our case, the use of nanosize Al 2 O 3 particles (<25 nm), lower HFIH sintering temperatures (1600℃) and shorter dwell time (∼3 min) facilitate Al 2 OC formation at the interface. 42,43 Based on structural and thermal investigations, it is presumed that Al 2 OC phase formation occurs in a two-step process; the presence of GNS causes carbothermal reduction of the Al 2 O 3 nanoparticles along with generation of gaseous Al 2 O and CO gas (equation (1)) followed by further reaction between Al 2 O and residual carbon to produce Al 2 OC phase (equation (2)). …”

Section: Resultsmentioning

confidence: 99%

Chemical and structural analyses of the graphene nanosheet/alumina ceramic interfacial region in rapidly consolidated ceramic nanocomposites

Ahmad

Islam

Alharthi

et al. 2017

Journal of Composite Materials

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Graphene nanosheets (GNS) reinforced Al2O3 nanocomposites were prepared by a rapid sintering route. The microhardness and fracture toughness values of the resulting nanocomposites simultaneously increased due to efficient graphene nanosheet incorporation and chemical interaction with the Al2O3 matrix grains. The properties enhancement is attributed to uniformly dispersed graphene nanosheet in the consolidated structure promoted by high surface roughness and ability of graphene nanosheet to decorate Al2O3 nanoparticles, strong GNS/Al2O3 chemical interaction during colloidal mixing and pullout/crack bridging toughening mechanisms during mechanical testing. The GNS/Al2O3 interaction during different processing stages was thoroughly examined by thermal and structural investigation of the interfacial area. We report formation of an intermediate aluminum oxycarbide phase via a confined carbothermal reduction reaction at the GNS/Al2O3 interface. The graphene nanosheet surface roughness improves GNS/Al2O3 mechanical attachment and chemical compatibility. The Al2O3/GNS interface phase facilitates efficient load transfer, thus delaying failure through impediment of crack propagation. The resulting nanocomposites, therefore, offer superior toughness.

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“…Formerly, using this process on reactive metals has been of little commercial value, since the products obtained are usually a mixture of the free metal with undesired metal oxides and carbides (Stroup, 1964;Wilhelm, 1964), requiring an expensive separation of the metal component from the residue. Anderson andParlee (1974, 1976) have developed an economically attractive carbothermic reduction scheme for converting metal oxides to the metal in good yields without the formation of metal carbides, oxycarbides, suboxides, and other undesired products that characterized the previously-known form of carbothermic reduction.…”

Section: Introductionmentioning

confidence: 99%

A chemical theory for the thermodynamics of highly‐solvated liquid metal mixtures

et al. 1982

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SCOPEThe proper use of liquid metals as solvents makes possible a wide range of new and advantageous chemical processes. For example the carbothermic reduction of reactive metal oxide ores in appropriate solvents could represent very substantial savings over the conventional, highly energy-intensive electrochemical production of aluminum, magnesium, and titantium. Traditionally the refining of pure reactor grade zirconium from ziconia by chemical separation of the hafnium impurities has been most difficult, but the Zn-Hf reduction and separation may be. accomplished directly and virtually quantitatively in a proper metal solvent. Solvent metal processes have even been shown to be successful in the separation of uranium from fission byproducts, thus leading to an environmentally acceptable and secure method for the reprocessing of spent nuclear fuel elements. All of these processes are currently at bench scale, and for implementation a mathematical model is required for scale-up. All depend on the unique thermodynamic properties of liquid metal solutions, and in this work a chemical theory of solutions is used to characterize the strong interactions of solutions forming intermetallic compounds, when activity coefficients may deviate from Raoult's law by many orders of magnitude. Such models should be instrumental in the investigation, development, and rational design of liquid metal solvent processes. CONCLUSION AND SIGNIFICANCEStrongly solvating (compound-forming) liquid metal mixtures can be well characterized thermodynamically by a chemical model of solution behavior. Using such a model, the liquid activities are well represented for mixtures forming either a single or multiple compounds. In addition the method is successfully extended to multicomponent systems and to the representation of the solid-liquid phase boundary. Since such systems always exhibit strong negative derivations from Raoult's Law, liquidliquid equilibria never occurs. The model presented is capable of accounting for both "physical" and "chemical" forces, and the general equations are developed. For the systems studied the compound formation is generally quite strong and the physical forces may be considered negligible by comparison. This assumption permits a direct linear least-squares solution of the equations to find the equilibrium constants for compound formation, which are the only parameters in the excess Gibbs energy equation. The chemical model is shown to be far superior for these systems to the traditional solutions to the Gibbs-Duham Equation; the Redlich-Kister, Van Laar, and Wilson equations are mathematically incapable of representing such systems.

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Carbothermic smelting of aluminum

Cited by 9 publications

References 4 publications

Solubility of carbon in liquid Al and stability of Al4C3

Solubility of carbon in liquid Al and stability of Al4C3

Chemical and structural analyses of the graphene nanosheet/alumina ceramic interfacial region in rapidly consolidated ceramic nanocomposites

A chemical theory for the thermodynamics of highly‐solvated liquid metal mixtures

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