Flux Tank Handling and Protection
Table of Contents
Flux Management
As outlined in our blog post, Flux and Its Role in the Galvanizing Process, maintaining consistent flux conditions throughout the galvanizing process is crucial for optimal results. To help ensure your flux tanks remain in top condition, here are several best practices that can significantly improve your flux management:
- Regular Additions:
Every time material is dipped, the flux bath weakens, leading to a decline in coating quality. Weak flux can cause various issues such as poor coating, excessive coating thickness, and increased dross formation. To avoid these problems, it’s essential to keep the flux concentration between 400-550 g/L. A reliable method is to calculate the required flux amount and add 1 or more bags daily. Rather than adding all the flux to one side of the tank, distribute it evenly across the bath. This helps maintain a consistent flux concentration throughout the tank, ensuring even coating and better overall quality.
- Proper Rinsing Before Flux:
The flux tank is the heart of the pretreatment process, and it should be maintained as the cleanest tank in the entire plant. Contaminated flux will negatively impact the galvanizing process and lead to unnecessary costs in the zinc kettle. Using two rinsing tanks before the flux tank is ideal. After rinsing, allow sufficient time for the solution to drain properly, never carry dirty rinse water into the flux tank. This ensures the flux remains uncontaminated and preserves its effectiveness.
The key focus should be on preventing contamination of the flux by iron (Fe), as it can cause a range of issues in the galvanizing process.
Why Iron Content in the Flux Tank Matters?
Iron dissolved in the flux poses a significant challenge. When steel is dipped into flux contaminated with iron, it will be coated with both flux and iron. This iron is then carried into the zinc kettle, where it reacts with zinc, forming dross. For every 1 gram of iron, 19 grams of zinc will bond with it, creating 20 grams of dross. As a result, a high iron content in the flux leads to increased dross, causing zinc loss and higher operational costs.
Additionally, low pH in the flux can cause pickling of the steel and create iron, further increasing dross formation. To prevent this, the pH in the flux tank must be maintained between 4 and 5.
Skipping the rinsing process or not waiting long enough for the rinsing solution to drain can inadvertently transfer iron contamination into the flux tank, further contributing to dross formation.
How to Remove Iron from the Flux Tank?
Unfortunately, removing iron from the flux tank isn’t as simple as contaminating it, and there’s no quick fix you can implement manually. However, don’t worry— we have developed an innovative solution: the ANI – Flux Treatment Machine.
The ANI Metal Automatic Flux Treatment System is a proven and effective solution for flux regeneration. It keeps the flux bath free from iron (<1 gr/lt) through a continuous, automated process. Hydrogen peroxide is fed with a constant (adjustable) value according to the Fe2+ and Ammonia is fed according to the pH. This process allows iron hydroxide to precipitate out as a solid, which is then filtered as red mud, leaving the clean flux to return to the tank.
The Importance of Flux Maintenance
Maintaining a clean and efficient flux tank is far more cost-effective than dealing with the consequences of contaminated flux. Regular maintenance of the flux tank ensures high-quality, uniform coatings and minimizes zinc loss.
For more information on how to optimize your flux tank to improve your galvanizing process, be sure to visit our Flux Treatment page.