摘要 |
The invention relates to organoaluminum electrolytes for the electrolytic deposition of high-purity aluminum, which are characterized in that they contain mixtures of organoaluminum complex compounds of the type MF ~ 2 AlR3 (A), wherein M represents potassium or mixtures of K with a maximum of about 15% by mole of sodium, as well as trialkylaluminum AlR3 (B) which has not been complexed to an alkali metal fluoride in a molar ratio of A . B of from 4:0.6 to 4:2, as well as a polyfunctional Lewis base of the type R'-OCH2CH2-OR" (C) in a molar ratio of B : C of from 1:0.5 to 1:1. The organyl radicals R in A are ethyl groups (Et), methyl groups (Me) and iso-butyl groups (iBu) in a molar ratio of Et: Me:iBu as 3:m:n, wherein m and n are numerical values of between 1.1 and 0 and the sum (m+n) is from 0.75 to 1.4. As the solvent for said electrolytes there are used from 3 to 4.5 moles, relative to the amount of alkali metal fluoride employed, of an aromatic hydro-carbon which is liquid at 0 .degree.C or a mixture of such hydrocarbons. The invention further relates to a process for the electrolytic deposition of high-purity aluminum by using said electrolytes.
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