• graphite electrodes
    Antioxidation Treatment

The graphite electrodes consumption is one of the most important costs in financial melt shop management. This cost should be optimized and reduced.

The electrodes consumption is composed of:

LINEAR TIP CONSUMPTION (around 60-70%) - current passage
(IT HAPPENS ONLY DURING POWER-ON)
The linear tip consumption is strictly connected to the amount of current flowing through the electrode, and the consumption index is proportional to the squared value of the current (I2). The melting power depends mainly from electrical current and decreasing it produces, in many cases, a drop in steel production.
UHP Grade





SIDE CONSUMPTION (around 30-40%) - graphite oxidation
(IT HAPPENS ALL THE TIME DURING PRODUCTION)
We have two types of oxidation:
The low-temperature oxidation (500<>800°C) occurs on the column part above the roof up to the clamp. The low-temperature oxidation destroys the connections between the grains of graphite and can flake the outer surface of the electrode. The high-temperature oxidation occurs on the column under the furnace roof (800<>2400°C in the tips) and increases proportionally to the amount of oxygen available for reaction. Here the rate of reaction is higher due to the movement of dissociated oxygen atoms. The effect is often so intense to generate a ”conical" shape to the tip of the electrode.
UHP Grade


ULTRA - 3H ANTI OXIDATION SOLUTION

MISANO Engineering applies and anti-oxidation treatment to the electrodes. With the usage of an autoclave, we perform an impregnation of the graphite electrodes with a solution made of aluminium particles, developed in cooperation with the laboratories of SHINTO Japan (POWER-3T).

The parameters that determine the infiltration rate in the material are:

ON 2013, MISANO ENGINEERING HAS INSTALLED A NEW TREATMENT STATION.

Electrodes loading

Electrodes are loaded into the treatment tank before the vacuum is created through the action of a mechanical pump;

Antioxidation liquid

The anti-oxidation liquid flows from the storage tank to the treatment tank according to the required program parameters;

Return of liquid

The liquid is sucked in the storage tank and the electrodes are extracted and then dried inside a gas furnace;

The new system uses a liquid with a higher concentration of anti-oxidation components (POWER-3H) and allows to modify the temperature of the anti-oxidation liquid, that is another parameter that improves the infiltration rate.

Heating system
The heating system into the storage tank has a scope to heat the liquid to 60/65°C before it flows inside the treatment tank.

Increasing the temperature of the liquid improves the original physical properties such as viscosity, to increase the penetration into the electrodes.

"Warm liquid" and "high concentration" are the main features of the new generation treatment:

ULTRA – 3H

After the electrodes drying phase, the anti-oxidation particles are strongly bonded to the graphite domains. This condition concurs to fight the natural effect of oxidation and delays its occurrence.

MISANO performs the ULTRA-3H treatment on electrodes with all the diameters, for EAF and LF applications, for the qualities HP, SHP and UHP.

Moreover, thanks to the customization of the treatment recipes, we guarantee a uniform absorption constant among all electrode qualities.

database of the recipes
The parameters used for each customer are stored to make sure to provide a uniform impregnation of every batch we deliver.

The treatment ULTRA – 3H doesn’t change the electro-physical properties of the electrodes and doesn’t leave any residues on the current contact pads.
At the end of the treatment, we register an increase of the density around 1% and a decreasing of the resistivity around 0,3-0,6%.
The aluminium particles are volatile and don’t impact the chemical composition of the steel.
The thermal expansion, the flexural strength, the compressive and tensile strength of the electrodes remain unchanged.

The anti-oxidation treatment ULTRA–3H is available in the facilities of Italy, United Arab Emirates and China.

ULTRA 3H locations
graphite electrodes