Gentle descaling for galvanized surfaces – ZINKOFIX

Depending on the type of metal present in the system and the composition of the coating, a suitably formulated stone removal agent must be used. We always supply pre-balanced combination products of acid and corrosion inhibitor, allowing our customers to begin the chemical remediation of their systems immediately.

ZINKOFIX – Water scale remover for galvanized containers, cooling towers, pipelines, etc.

Descaling of hot water boilers:

ZINKOFIX is suitable for descaling virtually all boilers; in particular, it can also be used to descale galvanized boilers, boilers with enamelled surfaces, stainless steel boilers, etc. If a sacrificial anode is present (this usually consists of magnesium and serves as corrosion protection), it must be removed before descaling.

The amount of material required depends on the extent of limescale buildup in the boiler, but is generally about 5-10% of the water content of ZINKOFIX (i.e., about 5-10 kg of ZINKOFIX is needed for a 100-liter boiler).

However, if the amount of limestone is known, the ZINKOFIX requirement can be calculated precisely (4 kg of ZINKOFIX are required for 1 m² of limestone surface and 1 mm of limestone coating; see also the ZINKOFIX data sheet).

Summary of the procedure:

• The boiler must be empty and cold before descaling begins.
• From an open intermediate container, water is pumped via a peristaltic pump into the cold water inlet of the boiler; a hose is attached to the hot water outlet of the boiler and the other end is hung in the intermediate container; the ZINKOFIX solution is prepared in the intermediate container and then pumped through.
• If the ZINKOFIX solution is still active but no longer foaming, the solution is drained (neutralize beforehand!), the boiler is filled with water and emptied again
• After pumping with SILIKO-GEL-pH6 (post-treatment agent), it is emptied again and rinsed with water.
• Disassemble the hose connections, reassemble the system and flush with water until it runs clear and odorless.

Descaling of cooling circuits:

The amount of material required depends, of course, on the amount of limescale present. If the amount of limescale is known, the required amount of ZINKOFIX can be calculated (see ZINKOFIX data sheet).
However, the amount of limescale in a cooling circuit often cannot even be estimated accurately. In such cases, the following rule of thumb has proven useful in practice:

• The ZINKOFIX requirement is approximately 5-10% of the minimum water volume required to operate a cooling tower. Therefore, if the minimum water volume in a cooling circuit is, for example, 5,000 liters, the ZINKOFIX requirement is approximately 250-500 kg.

It is also important that the destoning process with ZINKOFIX may only be carried out at room temperature (max. 30°C).

Summary of the procedure:

• Loose limescale and dirt are removed mechanically. The minimum water level necessary for proper cooling tower operation is then set. The cooling tower fans remain switched off for the entire duration of the cleaning process.
• The calculated amount of ZINKOFIX, based on the water content of the system (at least 5%), is pre-dissolved in water and added to the cooling tower basin; circulation pumps are switched on for a maximum of 2 minutes, then a 15-minute break – this process is repeated.
• Once the sludge and gas formation is complete and the ZINKOFIX solution is still active (reacting with limestone grit), the cooling system is emptied (usually after 4-8 hours). Neutralize with limestone grit beforehand!
• Intermediate rinse with water – introduce a 1% TRINEUTRAL solution, pump over, check pH value (at least 7), drain.
• Finally, rinse again until the system is clean.