Electrolytic cleaning of rectifier tanks

IN UNDERTAKING a general overhaul of a mercury arc rectifier at periodic intervals, the problem of interior cleaning of the tanks always has been a troublesome one. The tank in use usually has accumulated considerable contamination of loose material eroded from the elements of the rectifier. In addition to a dirty condition of the mercury pool, a quite hardened black slick scum may cover a large area of the tank walls. After removing all the interior parts, past practice has been either to sand-blast or wire-brush the tank walls and bottom in an effort to furnish a clean tank for the introduction of the new mercury needed for further operation.