Aluminum Company of America

Donald L Stewart

Utah Tsao

Alfred F LaCamera

Jan H Van Linden

Thomas R Hornack

John M Urbanic

David A Wohleber

Roger C Johnson

Thomas V Pierce

James O Parkhill

Jan H vanLinden

A process is disclosed for treating salt-containing aluminum dross to remove potassium and sodium chloride salts therefrom. The process generally comprises treating the dross in a first treating step with a leaching solution having a pH maintained in the range of about 6-7 to remove a portion of the salt content thereof; filtering the residual solids from the first leaching solution; and treating the filtered solids in a second treating step with a second leaching solution having a pH maintained above about 8, and preferably above about 9. The pH of the first leaching solution is maintained in the desired range by the addition of hydrochloric acid, and the pH of the second leaching solution is maintained in the desired range by the addition of potassium and/or sodium hydroxide.

Process for the removal of salts from aluminum dross

Salt-based melting process

A method is disclosed for preventing the condensation of aluminum chloride (AlCl.sub.3) in a fractional distillation column which is operated to separate a fraction which does not include AlCl.sub.3 from a mixture containing AlCl.sub.3 and other metal chlorides and which is operated at temperatures which include the sublimation or melting points of AlCl.sub.3 at the operating pressure of the column. According to this method, titanium tetrachloride (TiCl.sub.4) is maintained in the column in an amount at least as great, by weight, as the amount of AlCl.sub.3 contained in the mixture.

Method for preventing the undesirable condensation of aluminum chloride

Metal chlorides such as aluminum chloride (AlCl.sub.3) are separated from a mixture containing metal chlorides including AlCl.sub.3 and ferric chloride (FeCl.sub.3). In order to effect this separation, the mixture is subjected to a fractional distillation process utilizing an array of distillation columns. According to this process, the mixture is introduced into a first distillation column which is operated at temperatures and pressures sufficient to separate FeCl.sub.3 from the mixture while avoiding the formation of a solid solution of FeCl.sub.3 and AlCl.sub.3 within the column. At least one additional distillation column is then employed to separate metal chlorides from the remaining mixture from the first column.

Fractional distillation process for the production of aluminum chloride

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Greensburg, PA, United States of America

Donald L Stewart