Decalcification with KALZITIN

The (dis)solution of the problem:

Acids armed with special corrosion inhibitors are used to remove calcium deposits. These anti-corrosive agents have been developed to protect metals against acidic attacks – an invisible (mono-molecular) protective film abates on the metal, not affecting the scale, so that the acid is free to remove the deposits.

The kind of descaling agent to be applied depends on metals existing in the system and composition of the scale. We offer perfectly balanced multifunctional products consisting of the appropriate acid and corresponding anti-corrosive agents, enabling our clients to start with descaling immediately. Against limescale our best established product is KALZITIN.


KALZITIN is available in two versions:

KALZITIN – most frequently employed dissolvent for boiler and mineral scale as well as rust, for vessels and pipes made of iron or steel.

KALZITIN-K – descaling agent especially for heat exchangers (and other vessels) made of copper and iron.

Method of Application for Boiler Decalcification

After assessment of the solubility of the scale deposit in KALZITIN and after calculating the amount of KALZITIN presumably needed, one has to checked wether the boiler / tank / pot / container in question is cooled down sufficiently (30°C maximum) and wether it is empty.

Thereafter one would have to continue as follows:

I. Filling and Dying of KALZITIN:

For boilers possessing a big water reservoir filling of KALZITIN is best achieved with the help of an acid pump (e.g. a BOY descaling pump) by using the topmost manhole or a cleaning opening.

In most of the cases, the amount of KALZITIN needed for the dissolution of the scale is smaller than the boiler volume. In these cases, KALZITIN has to be diluted with the respective amount of water. For bigger water reservoirs this is carried out as follows: some of the water for dilution is filled into the boiler first, then (or maybe at the same time) the calculated amount of KALZITIN is pumped in, and finally, the boiler is filled to the minimum level with water for dilution.

For an enhanced mixing of the components for descaling, the solution can be circulated in such a way, that the suction hose of the pump is connected to the water reservoir at a point as low as possible and the outlet (of the pressure hose) is situated at or as near as possible to the water level. If the pump remains switched on for one or several hours, depending on power and boiler volume, the KALZITIN-water mixture is continuously pumped from the bottom of the boiler to the top, and thus an exhaustive mixing is achieved.

For boilers possessing a small reservoir (relatively small water volume) like all water-tube boilers (e. g. radiant type boilers), quick steam generator etc., filling in KALZITIN is best achieved by pumping in the solution at the lowest point possible. As a large quantity of carbon dioxide is formed when dissolving the scale, care has to be taken to provide for an opening at the highest point of the system (air vent).

II. Interaction Time:

The interaction time depends on the amount and on the composition of the deposits to be dissolved. For boiler scale of high solubility and high carbonate content, which foams strongly when dissolved, interaction times of a couple of hours or over night are sufficient.
For boiler scale with higher contents of insoluble components, interaction times of 12 – 24 hours are required. To dissolve thick layers of rust as well as deposits containing gypsum or silicates, it might be necessary to heat the KALZITIN solution, whereupon the addition of 1.5 – 3.0 kg INHIBITOR-KFF per m3 solution is necessary. Care has to be taken that the temperature does not exceed 60°C.

Heating of KALZITIN solution when INHIBITOR-KFF is added:

After addition of INHIBITOR-KFF the burner is switched on for 2 minutes maximum. After 10 minutes the temperature of the boiler water is measured. It is necessary to wait for a complete mixing of the KALZITIN solution.
This procedure is repeated until the temperature of the KALZITIN solution has reached 60°C.

In any case, good mixing has to be provided. The KALZITIN treatment is terminated when the gas formation has stopped although the KALZITIN solution is still active (formation of foam with lime or mortar).

III. Aftertreatment:

After KALZITIN treatment the boiler is emptied; it has to be noted, that the remaining solution still contains free acid. This acid must be neutralized carefully before releasing the solution into the sewage system.

The drained boiler is once again filled with clean water, re-emptied and spouted. The system is then filled with a 0.5 – 1 % (bw) TRINEUTRAL solution for after-treatment. A neutralisation of remaining KALZITIN is achieved when the well mixed TRINEUTRAL solution in the boiler shows a pH value of 8 to 9. To achieve an uniform dissolution of TRINEUTRAL it is advisable to pump a TRINEUTRAL suspension into the boiler which is filled with water by approx. two thirds. To this end, the TRINEUTRAL is mixed in an open container with a large quantity of water (e. g. 1:10) and the supernatant solution is pumped into the boiler. Remaining solid matter is dissolved by mixing it with added water until all remains are dissolved; the resulting solution is pumped into the boiler. By no means is it allowed to throw the solid TRINEUTRAL simply into the boiler, as it would then sink to the bottom and would be dissolved very slowly.

Precautionary measures for the use of KALZITIN and other descaling agents:

Corresponding material safety data sheets must be observed unconditionally!
KALZITIN is an acidic reagent and can, therefore, affect surfaces that are not acid-resistant. Skin and clothes should not come in contact with KALZITIN. Rinse spills and sprinkles of KALZITIN immediately with a large quantity of water. During and after a treatment with KALZITIN, a boiler or a container must not be inspected with an open flame, as flammable gases might be present. Additionally, it is only allowed to enter a boiler cleaned with KALZITIN when it is thoroughly ventilated.

KALZITIN is allowed to be fillled into a cooled down boiler system only.