
Carbide in Metallurgy
Calcium carbide is a strong reduction chemical. It could also be used as a good and viable source of energy. This method has the most application in metallurgy. Because by implementing different methods it could be used as means of reducing concurrent costs.
In modern steel making operation and with ever increasing trends in casting there is an increasing demand for steel with reduced sulfur; therefore, increase in demand for calcium carbide shall be evident. It goes without saying that this increase in demand of calcium carbide is for the application of desulfurization. In addition to all that, calcium carbide shows a strong reaction with oxides, thus producing a large amount of heat. This heat is stored in the process that shall increase the efficiency in metallurgy. It goes without saying that calcium carbide could be considered as viable source of energy that will increase the productivity of steel making furnaces.
Desulfurization (Direct)
In modern steel plants there is less need for sulfur. Because the demand for casting parts is increased and calcium carbide is best suited for reducing the amount of sulfur in molten metal, there is a high demand of calcium carbide in steel making industry.
But this is accomplished by using magnesium where part of the sulfur is removed from the molten metal while being transferred in the ladle. Then the remaining sulfur is removed by the calcium carbide. In foundry manufactures, where molten iron is used, before the iron is injected into the mold, it must be desulfurized. This is usually done by adding grains of the calcium carbide into the molten iron.
The purity level and sizes of the grains are some of the most important factors in the efficiency of the application of carbide. The grain size of the calcium carbide is selected with special care. This is to ensure that the most surface contact in provided.
The Carbide Industry produces 5 different sizes of calcium carbide grains to satisfy customers’ needs. These products with special formula can cause all calcium carbides in the slag to react or only a small amount left un-reacted. Calcium carbide powder is injected in lower layers. The grain size of the powder is less than 105 microns. The calcium carbide could be mixed with other types of industrial powders or other known chemicals.
Slag Conditioning
Calcium carbide is a very important and necessary material for removing iron oxide in the furnace that is transferred during the loading of the ladle. When the larger grains of the carbide are added after charging into the flow of molten metal, it will react with the oxide and the grade of iron and expensive alloys will increase. In addition, if this is left out as it is, it shall interfere with the purification of steal making and shall influence in the desulfurization. Therefore, the efficiency of desulfurization will be reduced and any added alloy shall be oxidized. As a consequence, this will destroy the refractories.
Although aluminum, ferrosilicon, silicon carbide and even coke have been used for this purpose, calcium carbide has proven to be economically viable. Calcium carbide produces CO gas which uniformly distributes and mixes the carbide while foaming the stage. This does not require to add any balancing line as do silicon-base additives do. In this process heat is produced that does not allow the stag to chill, and under normal conditions it does not dissolve in the steel and therefore no amount of carbon is produced and there is no unexpected oxidation. Almost all of the material is used.
For such application, the carbide industry can produce calcium carbide in desired grades to meet the requirements of the customers.
Furnace Injection
Calcium carbide has a unique capability in reaction with metal oxides. This is accomplished without any adverse effect on chemical characteristics of the steel. In spite of that, a significant amount of energy is produced in the process. In the electric arc furnace, the energy produced during the oxide reduction is accomplished by the heated line particles and CO gas. This material helps to retain the heat and foaming the stage.
In order for the slag produced in electric arc furnace not to remain in the ladle, all the capabilities of the carbide could be used. This, in turn, could increase the energy efficiency and therefore the process of alloy recovery in electric arc furnace shall be done expeditiously.
For furnace injection purposes, larger size of calcium carbide is produced. These are more suitable for transporting the material into the furnace under high pressure airflow. It goes without saying an inert gas is used for this purpose.