Environmental guidance for your business in Northern Ireland & Scotland

Fluxing baths

Fluxing baths: part of the galvanising process

After the surface of the item to be galvanised has been prepared by degreasing and acid pickling, it is immersed in a fluxing bath. The bath usually contains a solution of zinc ammonium chloride which prevents oxidation and increases zinc 'wetting'. The coated steel is then dried, either at ambient temperature or using the exhaust gases from the molten zinc bath.

What you must do

You must comply with your duty of care responsibilities when dealing with waste.

Duty of care - your waste responsibilities

You must not make any discharge to surface water or groundwater without consulting your environmental regulator. If you discharge without an authorisation, permit or consent from your environmental regulator you could be prosecuted and fined or imprisoned.

Water pollution

You must not discharge trade effluent to a public sewer without trade effluent consent or a trade effluent agreement with your water and sewerage company or authority. If you discharge without a consent or agreement you could be prosecuted and fined or imprisoned.

Trade effluent - discharges to sewers

The zinc ammonium chloride baths need to be periodically drained and replaced. Spent flux has hazardous properties that mean you will need to deal with it as hazardous/special waste.

Hazardous / special waste

Good practice

Use heat recovered from the zinc bath to raise the temperature of the fluxing baths.

Insulate the fluxing baths to reduce the amount of energy you need.

Cover the fluxing bath when it is not in use to reduce evaporation.

Ensure that the article is adequately dried after fluxing to prevent zinc splattering and poor surface finish at the galvanising stage.

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