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1. Influence of carbonizer particle size: The carbonization process using a carbonizer involves a dissolution and diffusion process as well as an oxidation and loss process. Depending on the particle size of the carbonizer, the rates of dissolution and diffusion as well as oxidation and loss vary accordingly. The absorption rate of the carbonizer depends on the combined effect of its dissolution and diffusion rate as well as its oxidation loss rate: under normal conditions, smaller carbonizer particles result in a faster dissolution rate and a higher loss rate, while larger particles lead to a slower dissolution rate and a lower loss rate. The selection of the carbonizer particle size is related to the furnace diameter and capacity. Generally, when the diameter and capacity of the furnace are large, the particle size of the carbonizer should be larger; conversely, the particle size of the carbonizer should be smaller. For crystal graphite melted in electric furnaces with a capacity of less than 1 ton, the particle size requirement is 0.5–2.5 mm; for those with a capacity of 1 ton to 3 tons, the required particle size is 2.5–5 mm; for furnaces with a capacity of 3 tons to 10 tons, the required particle size is 5.0–20 mm. The particle size of crystal graphite used as a lining in ladles is 0.5–1 mm. 2. Effect of the amount of carbonizer added: Under the same temperature and chemical composition, the saturated carbon concentration in the molten iron remains constant. The solubility limit of carbon in cast iron (=1.3+0.0257T0.31-0.33-0.45+0.028, where T is the temperature of the molten iron). At a certain saturation level, the more carbonizer is added, the longer the time required for dissolution and diffusion, the greater the corresponding loss, and the lower the absorption rate will be. 3 Effect of temperature on the absorption rate of carburizing agents: From kinetic and thermodynamic perspectives, the oxidizing tendency of molten iron is related to the equilibrium temperature of the C-Si-O system; in other words, O in the molten iron reacts with C and Si. The equilibrium temperature varies depending on the target C and Si contents; when the molten iron is above the equilibrium temperature, carbon oxidation occurs preferentially, with C and O forming CO and CO2. As a result, the carbon oxidation loss in the molten iron increases. Therefore, above the equilibrium temperature, the absorption rate of the carburizing agent decreases; when the carburization temperature is below the equilibrium temperature, the lower temperature reduces the saturated solubility of carbon, and at the same time slows down the diffusion rate of carbon, resulting in a lower yield as well; the absorption rate of the carburizing agent is highest when the carburization temperature is at the equilibrium level. 4 Effect of molten iron stirring on the absorption rate of carbonizers: Stirring facilitates the dissolution and diffusion of carbon, preventing the carbonizers from remaining on the surface of the molten iron and being burned away. Before the carbonizer is completely dissolved, the stirring time is long and the absorption rate is high. Stirring can also reduce the carbonation and holding time, thereby shortening the production cycle and preventing the loss of alloying elements in the molten iron. However, excessive stirring not only has a significant impact on the service life of the furnace, but also, after the carburizing agent dissolves, stirring exacerbates the loss of carbon in the molten iron. Therefore, the appropriate stirring time for the molten iron should be such as to ensure complete dissolution of the carburizer. 5 Influence of the chemical composition of the molten iron on the absorption rate of the carburizer: When the initial carbon content in the molten iron is high, within a certain solubility limit, the absorption rate of the carburizer is slow, the amount absorbed is low, there is relatively more burning loss, and thus the absorption rate of the carburizer is low. The situation is the opposite when the initial carbon content of the molten iron is low. Furthermore, silicon and sulfur in the molten iron hinder the absorption of carbon, reducing the uptake rate of carbonizers; whereas manganese facilitates the absorption of carbon, increasing the uptake rate of carbonizers. In terms of the degree of influence, silicon has the greatest effect, followed by manganese, while carbon and sulfur have a lesser impact. These are the main factors that affect the absorption rate of carbonizers!