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US 6,174,383 B1Granted
Method at treatment of metals
AssigneeEka Chemicals AB
InventorsCharlotte Angel, Troy Berglind, Arne Frestad, Sven-Eric Lunner, Anders Waleij
Life of this patent
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Abstract
The invention relates to a method at pickling of steel in an acidic aqueous pickling solution containing Fe3+ and Fe2+, wherein the steel is contacted with pickling solution that continuously is brought to circulate through a conduit into which hydrogen peroxide is supplied to oxidize Fe2+ to Fe3+.
Claims10
A method for pickling steel to remove an oxide layer from its surface comprising the steps of:
- (a) immersing steel in a bath of acidic pickling solution containing Fe2+ and Fe3+ ions;
- (b) pickling the steel by contact with the pickling solution in the bath;
- (c) continuously circulating the pickling solution in the bath by passing the pickling solution through a conduit;
- (d) oxidizing at least a portion of the Fe2+ ions in the pickling solution to Fe3+ ions by adding hydrogen peroxide to the pickling solution circulating in the conduit, the hydrogen peroxide being added in such an amount that the pickling solution which contacts the steel in the bath is substantially free of hydrogen peroxide.
1 more element
A method for pickling steel to remove an oxide layer from its surface comprising the steps of:
- (a) immersing steel in a vat of acidic pickling solution containing Fe2+ and Fe3+ ions;
- (b) pickling the steel by contact with the pickling solution in the bath, the pickling solution having a content of Fe2+ of from about 0.2 to about 35 grams/liter;
- (c) continuously circulating the pickling solution in the bath by passing the pickling solution through a conduit;
- (d) oxidizing at least a portion of the Fe2+ ions in the pickling solution to Fe3+ ions by adding hydrogen peroxide to the pickling solution circulating in the conduit, the hydrogen peroxide being added in such an amount that the pickling solution which contacts the steel in the bath is substantially free of hydrogen peroxide.
1 more element
Dependencies are inferred from the claim text.