Key points of furnace washing operation of silicon metal furnace
After the silicon metal smelting through the furnace wash, slag has been partially discharged, the furnace chamber than the normal smelting empty, thus reducing a lot of work for the maintenance of the lining. If it is planned to stop the furnace for a long time, even if not to repair the lining, but also to wash the furnace to make the chamber more empty, and then send electricity to open the furnace when the electrode is easier to insert into the charge, to improve the furnace temperature and as soon as possible to create favorable conditions for normal smelting. Therefore, the larger capacity of silicon metal electric furnace, before the suspension of the furnace have a washing process.
In the process of silicon metal smelting in special circumstances, for some reason, the furnace slag accumulation is too much, the crucible is very small, take all kinds of methods have failed to reverse the furnace condition can also be used to wash the furnace method of slagging, expand the crucible, and then newly charged smelting.
Smaller capacity electric furnace, furnace temperature is low, as far as possible not to wash the furnace operation.
The slagging agent used for furnace washing is mainly lime. When the material surface is not lowered enough or electrode work end short (because not roasted well can not be put down), in the lime also with the right amount of silica (20 ~ 30% of the amount of lime). In order to improve the fluidity of the slag, sometimes 20 to 30 minutes before the slag release also add 10 to 20% of the amount of limestone fluorspar.
Why add slag-making agent can make it thin? Because the material in the furnace is mainly SiO2, Al2O3, SiC and the first three impregnated with coke particles. SiO2 and Al2O3 are acidic and neutral oxides, both have a high melting point, especially where there is also a considerable amount of SiC and C solid particles with a very high melting point. Therefore, even at very high temperatures they are still very viscous, but when lime is added, alkaline CaO combines with SiO2 and Al2O3 to form a low melting point, good flowability of the slag, while the SiC and C, due to the increase in the amount of slag and its improved mobility, can be adequately diffused and destroyed, its concentration is greatly reduced, so that the slag is easily discharged from the furnace.
The furnace washing operation is such that, in order to reduce the furnace washing workload and to ensure that the electrode can adequately heat the furnace bottom, the charge level is lowered starting eight hours before the furnace washing, as much as possible. Furnace washing is operated under open arc, the electrode is consumed quickly due to strong oxidation and scouring by air and slag, so the electrode should be ensured to have a long enough working end. After the material surface is lowered, lime can be added one after another to wash the furnace. Generally, 1~2 furnaces can be washed. The amount of lime to be added to each furnace should be determined by the size of the furnace capacity, how much slag inside the furnace, etc. The amount of lime to be added to the larger capacity electric furnace is about 4 tons per furnace.
Washing furnace is a heavy operation, such as not very careful will also occur safety accidents, so pay special attention to the following points: 1.
1. The temperature at the furnace mouth is very high when washing the furnace, always observe the operation of the equipment, especially the water cooling system, to prevent water leakage, so as to avoid explosive accidents.
2. must ensure that no hard breakage of electrode accident
3. The amount of slag discharge when washing the furnace is very large, we must especially strengthen the work before the furnace, prepare the table bag, keep the site before the furnace dry and water-free, and do not stack flammable materials such as oxygen bottles nearby to prevent burn-through accidents and safety accidents due to slag overflow.
4. Because the furnace wall by a large number of good mobility of the slag erosion and erosion, easy to produce running eyes and furnace mouth burn through the accident, should be noted.
The above is the key and operation of furnace washing in the silicon metal smelting process. If you want to know more about silicon metal or want to purchase silicon metal please contact me.
