Carbon Electrode Paste

Common Sense

Management of carbon electrode paste

If any dirty carbon electrode paste is put into the electrode barrel due to the bad management, it will cause local overheating and breakage of the electrode due to the different composition in different parts of the electrode. Therefore, during storage, transportation and use of carbon electrode paste, the following precautions should be paid special attention:

The storage area of carbon electrode paste should be a cement floor to strictly prevent the mixing of soil and impurities;

The carriage for transporting carbon electrode paste must be cleaned, and it is strictly prohibited to mix with coal powder, dust or other impurities;

The standby carbon electrode paste should be carefully managed and covered with a tarpaulin to avoid prolonged exposure to wind and sun, which may lead to mutual adhesion or quality deterioration.

Roasting of self-baking electrodes

In the smelting process, with the electrode is consumed and lowered, it is necessary to continuously add carbon electrode paste and continuously connect to lengthen the electrode barrel from the top. In this process, the height of the paste column should be well controlled so that the sintered electrodes with good quality can be produced by roasting.

According to the baking temperature and location, the baking process of self-baking electrodes can be roughly divided into the following three stages:

• The softening stage
• The volatile stage
• The Sintering stage

The methods to judge the sintering quality of electrodes

If it is found that the surface of the lowered electrode appears greyish white, dark but not red or just slightly red, it means that the baking is good; if the surface of the lowered electrode is red, it indicates the electrode is overburnt; if the surface appears black, it means that the electrode is underburnt. It can also be judged according to the smoking condition of the lowered electrode: it is normal if there is a small amount of smoke emitting from the lowered electrode; if there is no smoke, it means overburnt; if there is heavy smoke, it means underburnt. In addition, you can also use steel rod to poke the electrode that has just been placed under the lower edge of the copper tile: if the electrode is very hard and the steel rod can bounce back, it indicates it is overburnt; if the electrode is elastic, it means normal; if it is soft, it means underburning.

Common accidents of electrodes

Premature sintering: The carbon electrode paste has been sintered and hardened on the upper edge of the copper tile, which is called premature sintering. Premature electrode sintering will cause poor contact between the copper tile and the electrode, arcing and burning the copper tile, and it will also lead to hard break of the electrode.

Leakage paste: liquid or semi-liquid carbon electrode paste flowing out from the broken part of the electrode barrel is called leakage paste. In case of leakage paste, the power should be cut off immediately. Otherwise, the whole cylinder of carbon electrode paste may flow into the furnace, causing a serious accident. A slight leakage may easily cause such accidents as electrode soft breaking from the leakage paste.

Hard break: The break of the electrode at the sintered part is called hard break. In case of hard break, the electrode usually turns reddish first at some small cracks, and then become brighter and brighter, and suddenly, it turns white and is broken by arcing. At the time of hard break, there will be dazzling arcs and sounds, and the indication of the ammeter suddenly returns to zero.

Soft break: The break that occurs before the electrode is burnt ready is called soft break. Soft break is the most troublesome type of electrode accident. It is necessary to pay attention to all factors that may cause bad electrode sintering or electrode softening, and toc check and adjust all the factors that affect sintering effect frequently.

Carbon electrode paste suspension: The carbon electrode paste is suspended in the electrode barrel, which causes a larger space in the electrode barrel. This phenomenon is called carbon electrode paste suspension. If the carbon electrode paste suspension is not found and handled in time, when the empty electrode barrel enters the copper tile, it will burn the electrode barrel, causing an electrode breaking accident and affecting the normal operation of the electric furnace.

The causes of electrode accidents are various, and corresponding accident treatment methods and preventive measures are also different accordingly.

The normal roasting operation of the electrode depends not only on the quality of the carbon electrode paste, but also on various factors such as the type of the electric furnace, product type, furnace transformer parameters, roasting quality, operation, etc. These factors restrict and influence one another, and any one of the factors may influences other factors, even the normal production of the furnace.

If the electrodes management fails to meet the needs, various electrode accidents such as premature electrode sintering, paste leakage, hard break, soft break, and suspension may occur. After the occurrence of electrode accident, due to power outage or load reduction to deal with the electrode, the furnace condition will deteriorate, causing the electrode to rise and the temperature of the furnace bottom to drop, the output will decrease significantly, and the power consumption will increase. At the same time, due to abnormal furnace conditions and reaction on the electrode, the electrode breaks once more or underburnt. Electrode accidents will cause a large amount of electrical energy consumption, a large amount of raw material losses, reduced production capacity, and huge economic losses. Therefore, the correct roasting and management of electrodes is a fundamental measure to reduce electrode accidents, as well as an important link in the energy saving of electric furnace equipment.