The drag-out is the liquid of the coating bath that remains on the coated surface and it is removed by taking the object out of the bath.

The losses of the coating liquid of metallization depend on the shape of the products, the time available for removing the drag-out and the bath's temperature, which influences its viscosity. Baths with high concentrations and viscosities lead to the production of important quantities of drag-out.

The presence of a large volume of drag-out pollutes the following processing baths, with has as a consequence the reduction of the baths' life (eg when alkaline drag-out enters in acid bath). Moreover, the large amount of drag-out causes losses in chemical components, leading to the increased need of raw material, increases the quantity of produced mud and creates high requirements in water in order to clean the products after the coating.

A way to reduce the drag-out quantity is to provide to the coated object enough drain time. In addition, the spraying method can be used for rinsing the objects above of the coating bath and also the coating baths' temperatures should be increased in order to reduce the baths' viscosity and facilitate the drag-out removal.

Another effective way to reduce the drag-out is the careful and correct immersion of the objects in the coating baths, while the produced drag-out is going to be collected in existing tanks.













METAL PROCESSING
INDUSTRY



INTRO

- Production process
- Waste



GOOD PRACTICES
OF WASTE MINIMISATION


- Drag - out minimisation
- Water consumption reduction
- Baths' life extension
- Raw & auxiliary materials
substitution

- Housekeeping practices
- Metals' recovery
& water recycling