Aluminum carbides

The purest available aluminum powder is mixed with the stoichiometric quantity of pure, finely divided carbon the mixture is placed in a carbon crucible sealed with a carbon stopper and heated to 2000°C in an atmosphere of Hg. The heating is discontinued after 30 minutes. The product is orange and contains, in addition to AI4C3, a small amount of A1 metal. The carbide is ground to a powder and the metallic impurity removed by treatment with ice-cold concentrated HCl. The excess carbon floats on the surface and may be skimmed off. The purity of the product is directly related to that of the starting material. The presence of nitrogen results in the formation of nitrogenous compounds. 

The conversion may also be achieved by heating in hydrogen for three hours to 1500°C. A bright yellow, microcystalllne carbide results. 

Golden yellow, hexagonal leaflets. M.p. 2100°C, decomposes above 2200°C. Methane is evolved on hydrolysis. 

Anhydrous HCN is condensed in vacuum onto a frozen ether solution of LiAlH4 and the mixture is allowed to melt slowly. The theoretical amount of Hg is evolved and LiAl(CN)4 precipitates. If an excess of HCN is used, it may be removed by evacuation, together with the ether. The LiAl(CN)4 residue is a white powder. 

Hydrolyzes readily. Decomposes after some time even in the absence of oxygen and moisture. 

---

Lead dioxide Aluminum carbide, hydrogen peroxide, hydrogen sulfide, hydroxylamine, ni-troalkanes, nitrogen compounds, nonmetal halides, peroxoformic acid, phosphorus, phosphorus trichloride, potassium, sulfur, sulfur dioxide, sulfides, tungsten, zirconium... 

Aluminum carbide. Incandescence on heating Ammonia, Surfuric acid. Ammonia is oxidized with incandescence in contact with the per-... 

J. Paul, Alkali overlayers on aluminum, alumina, and aluminum carbide, Journal Vacuum Science Technology A 5(4), 664-670 (1987). 

Cowles An electrothermal process for making aluminum alloys. A mixture of bauxite, charcoal, and the metal forming the alloy (usually copper), was heated in an electric furnace and the molten alloy tapped from the base. The process cannot be used for making aluminum alone because in the absence of the other metal the product would be aluminum carbide. Invented by the Cowles brothers and operated in Cleveland, OH in 1884 and later in Stoke-on-Trent, England. The electrical efficiency was poor and the process was superseded by the Hall-Heroult process. 

Produces aluminum carbide when the powder metal is heated with carbon at 2000°C or at 1000°C in presence of cryolite. 

Aluminum Carbide, Al4Cj, pale yel hexag crysts, mp 2200°, subliming in vacuo at at 1800, reacts with w giving methane together with less than 10% hydrogen. This... 

Aluminum Corbide. See Aluminum Acetylide and Aluminum Carbide under Acetylides Aluminum Chlorate. See under Chlorates Aluminum Chloride. See under Chlorides Aluminum Chloride-Nitromethone Complex. 

A gas-reaction purification process also has attracted attention over the years. This is based on aluminum trichloride gas reacting with molten aluminum at about 1000°C to produce aluminum monochloride gas. Aluminum fluoride gas may he substituted for the aluminum monochloride gas in the process. Raw materials for the process may be scrap aluminum, aluminum from thermal-reduction processes, aluminum carbide, or aluminum nitride. As of the beginning of 1987, none of these other processes are fully commercial. 

Carbide Aluminum carbide A14C3, yellowish-green solid, by reaction of aluminum oxide and carbon in the electric furnace, reacts with H.O to yield methane gas and aluminum hydroxide. 

Aluminum carbide Diamond abrasive (for harder samples)... 

Aluminum is manufactured by the electrolytic reduction of pure alumina (A1203) in a bath of fused cryolite (Na3AlF6). It is not possible to reduce alumina with carbon because aluminum carbide (A14C3) is formed and a back-reaction between aluminum vapor and carbon dioxide in the condenser quickly reforms the original aluminum oxide again. 

D. Tzeli, A. Mavridis, First-principles investigation of the boron and aluminum carbides BC and ALC and their anions BC- and A1C-1. J. Phys. Chem. A 105, 1175-1184 (2001)... 

Zhang, J., Ekstrom, T.C., Gordeev, S.K., and Jacob, M. Carbon with an onion-like structure obtained by chlorinating aluminum carbide. J. Mater. Chem. 10, 2000 1039-1041. 

Carbides, (a) The aluminum nitride made in Preparation 13 contains a considerable amount of carbide AI4C3. Treat some of this product, or some commercial aluminum carbide, with 6 N NaOH in a test tube with a delivery tube. Collect some of the gas over water, which will dissolve all the ammonia. Test the combustibility of this gas and find that it bums with a nearly colorless flame. 

Nearly all the metals form carbides which will hydrolyze more or less readily. The hydrolysis products of aluminum carbide are methane and aluminum hydroxide... 

---