Method for removing iron ions from galvanizing flux solution

Abstract

A method for removing iron ions from galvanizing flux solution includes adding zinc chloride and ammonium chloride to a solvent in a preparing tank to prepare a first galvanizing flux solution which is transferred to a treatment tank, immersing an iron / steel piece in the first galvanizing flux solution to dissolve part of the surface to form iron ions, adding oxygen-rich gas to the first galvanizing flux solution to oxidize the iron ions to form a second galvanizing flux solution containing iron oxide precipitation, filtering the second galvanizing flux solution by a multilayer filter to form a third galvanizing flux solution without iron oxide or with low content of iron oxide, transferring the third galvanizing flux solution back to the treatment tank, and repeating the above steps by immersing another iron / steel piece in the first galvanizing flux solution so as to continuously remove iron ions generated.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention generally relates to a method for removing iron ions from flux solution, more specifically to a method for removing iron ions from galvanizing flux solution by oxidizing iron ions with oxygen-rich gas to form iron oxide precipitation without changing the content of zinc chloride and ammonium chloride in the galvanizing flux solution.[0003]2. The Prior Arts[0004]Traditionally, using the galvanizing flux solution to wet the surface of an iron piece is a common pre-treatment for hot-dip galvanizing, which facilitates the formations of the iron-zinc alloy layer with excellent corrosive-resistant property in the subsequent process so as to protect the iron piece from oxidations.[0005]In the wetting process, the surface of the iron piece is partly dissolved in the galvanizing flux solution to form iron ions, which may cause the molten zinc to form unwanted zinc ash in the latter hot-dip galvanizing proce...

AI Technical Summary

Benefits of technology

The present invention continuously removes iron ions from immersing an iron / steel piece into a galvanizing flux solution and maintains the content of zinc chloride and ammonium chloride without adding more. This ensures a continuous wetting effect on the surface of the iron / steel piece and helps in coating it with a zinc layer for protection against corrosion. It also helps in forming an iron-zinc alloy layer that has excellent resistance to oxidation.

Problems solved by technology

In the wetting process, the surface of the iron piece is partly dissolved in the galvanizing flux solution to form iron ions, which may cause the molten zinc to form unwanted zinc ash in the latter hot-dip galvanizing process.

As a result, the property of the iron-zinc layer is seriously deteriorated and the ability of anti-corrosions is greatly weakened.

As a result, the fabricating cost is increased.

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