Process for electrolytically coating a steel object on one or both sides

A process for electrolytically coating a steel object on one or both sides, preferably a steel strip with zinc or a zinc-iron alloy, in which the object is connected as the cathode in a galvanic cell and metallic zinc or a zinc-iron alloy is deposited upon the object from an aqueous solution of zinc chloride with a pH of 0.1 to 3.0, and preferably 1.0 to 2.0, using insoluble anodes. For the deposition of metallic zinc, the concentration of the zinc chloride solution is set from 50 to 1000 g/l ZnCl2 and that of divalent iron ions from 0.5 to 60 g/l and the mol ratio of zinc to iron in the electrolyte is maintained at 3 or over. Part of the flow of the electrolyte solution is preferably continuously fed into a column filled with metallic zinc in which the trivalent iron is reduced during electrolysis to divalent iron and at the same time metallic zinc is dissolved. In order to deposit a zinc-iron alloy, the mol ratio of zinc to iron in the electrolyte is set at under 3. The invention also includes a device for the advantageous performance of the process.

Method of electrolytically pickling special steel

Process for electrolytical coating

Abstract: Process for the electrolytic coating on one side only of flat parts made of steel, in particular steel strips, with a metal or metal alloy, in particular with a zinc-nickel-allay, characterised by the application on both sides of the part of a thin layer of the same material as used for the coating on one side only; subsequent coating on one side only; and finally electrolytic dissolution of the thin layer on the side, opposite the side to be coated permanently. For dissolving an aqueous solution of an alkali or alkaline earth chloride, preferably sodium or potassium chloride, having a pH-value of 7 - 12, is used as electrolyte.

GALVANIZATION PROCEDURE - ONLY ONE SIDE OR BOTH SIDES - OF A TUNED STEEL.

In a process for single- and double-sided electrolytic zinc-plating of stainless steel, the latter in the form of a stainless steel strip is connected as the cathode in an electroplating cell, and metallic zinc is deposited on the stainless steel strip from an aqueous solution of a zinc salt at pH 1.0 to 2.5, preferably 1.5 to 2.0, whereby contact corrosion due to sheet is avoided; this is of great importance particularly in the automobile industry.

Method for electrolytically pickling metal strips

The invention relates to a method for electrolytically pickling metal strips (1), in particular stainless steel strips. In the pickling method (2), the metal strip (1) is descaled in a pickling solution (B) using an electric current, and the used pickling solution (6) enriched with metals is regenerated. The metals dissolved in the pickling acid (6) are separated from the regenerated pickling solution (B) as metal hydroxides (9). According to the invention, the metal hydroxides (9) are dissolved in acid (11) and the resulting metal-containing solution (14) undergoes a pyrohydrolytic treatment, preferably in a spray roasting reactor (15), in order to form metal oxides (16).

Verfahren zum elektrolytischen beizen von metallbändern

Den Gegenstand dieser Erfindung bildet ein Verfahren zum elektrolytischen Beizen von Metallbändern (1), insbesondere von Edelstahlbändern. Bei dem Beizverfahren (2) wird das Metallband (1) in einer Beizlösung (8) mit Hilfe von elektrischem Strom vom Zunder befreit und die verbrauchte mit Metallen angereicherte Beizlösung (6) wird regeneriert. Die in der Beizsäure (6) gelösten Metalle werden als Metallhydroxide (9) von der regenerierten Beizlösung (8) abgetrennt. Erfindungsgemäß werden die Metallhydroxide (9) in Säure (11) aufgelöst und die dabei entstehende metallhaltige Lösung (14) einer pyrohydrolytischen Behandlung, vorzugsweise in einem Sprühröstreaktor (15), zur Bildung von Metalloxiden (16) unterzogen.