Anodization at high current density

We did not feel any of these methods would work reliably on a commercial scale at current densities in the range of 300 mA cm"2 or for commercial periods (at least 4000 hr). Rudge s work9,10 with porous carbon anodes was a very elegant solution to the problem (and formed the basis for the Phillips Electrochemical Fluorination process), but the high electrical resistance of the porous carbon limited it to small anodes at high current densities or lower current densities on large anodes. 

Cominco in the late 1960 s developed a method to precondition the anodes in separate cells outside the circuit (2). The process involves the creation of a hard dense Pb02 layer on the surface of the anode by oxidation of the anode at high current density in an acidic fluoride-containing electrolyte. This preconditioning process takes 8-12 hours. In this process the... 

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