Aluminium; Its History, Occurrence, Properties, Metallurgy and Applications, Including Its Alloys

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1887 edition. Excerpt: ...There have been some improvements made in the form of apparatus over those used by Bunsen and Deville, designed to produce the metal on a commercial scale. The best one is that patented in Germany by Richard Gratzel. He uses melting-pots of porcelain, alumina, or aluminium, which serve also as negative electrodes. A number of these are placed in one furnace. The following section shows the arrangement (Fig. 16). The positive electrode K can be made of a mixture of anhydrous alumina and carbon pressed into shape and ignited. A mixture of alumina and gas-tar answers very well; or it can even be made of gas-tar and gas-retort carbon. During the operation little pieces of carbon fall from it and would contaminate the bath, but are kept from doing so by the mantle G. This isolating vessel G is perforated around the lower part at g, so that the chlorine gas liberated at K may escape through the tube 0', while reducing gases can be brought into the crucible by the tube 0'. To lessen the electrical resistance and to renew the bath of chloride or fluoride, D. R. Pat. No. 26,962. Fig. 16. bars of carbon, alumina, or magnesia are placed inside the isolating mantle Cr. This process is now being worked on a large scale in Germany, being also used for producing magnesium. There are works at Bremen and Hamburg. M. Duvivier states that by passing an electric 20 The Chemist, Aug. 1854. '1, current from eighty Bunsen cells through a small piece of laminated disthene between two carbon points, the disthene melted entirely in two or three minutes, the elements which composed it were partly disunited by the power of the electric current, and some aluminium freed from its oxygen-Several globules of the metal separated, one of which was as white and as hard as...