Study on the Effect of Aging on the Ability of Calcium Carbide for Hot Metal Desulfurization

Abstract

Industrial trials and laboratory study are carried out to investigate the effect of aging on the ability of CaC 2 in hot metal desulfurization. The industrial trials indicate that the time of storage of calcium carbide within the limit of industrial practice has no appreciable effect on its ability of desulfurization. In the laboratory, samples of CaC 2 are prepared by exposing them in air for different times to promote formation of a Ca(OH) 2 outer layer. The thickness of Ca(OH) 2 increases with exposing time. Thereafter, the aged CaC 2 samples are employed for desulfurization at 1673 and 1773 K for 8 min. For all the samples after desulfurization, layers of graphite and CaO are found between the remaining CaC 2 particles and the outer CaS layer. The desulfurization using CaC 2 is found to proceed by the diffusion of calcium vapor through the product layers and then its reaction with dissolved sulfur in the hot metal at the surface. No appreciable difference in the thickness of the CaS layer is found with the samples exposed to air for different times. This finding explains well the industrial results.

Study on the Equilibrium of Slag and Hot Metal at Tapping with Respect to Sulfur

“…A detailed description of the experimental setup can be found in previous publications. [4,5] The main feature of the experimental setup is shown in Figure 2. A high temperature furnace with super Kanthal heating elements was used.…”

“…Sulfur removal has become more and more crucial in steelmaking, especially for steels with extremely low sulfur content. While the final removal of sulfur is usually carried out in secondary steelmaking, for example, in ladle treatment, the process of reducing sulfur content in the liquid metal starts very often by hot metal desulfurization . Due to its great relevance, a number of studies on hot metal desulfurization using different agents have been conducted .…”

“…While the final removal of sulfur is usually carried out in secondary steelmaking, for example, in ladle treatment, the process of reducing sulfur content in the liquid metal starts very often by hot metal desulfurization. [1][2][3][4][5][6] Due to its great relevance, a number of studies on hot metal desulfurization using different agents have been conducted. [1][2][3][4][5][6][7] The charged sulfur in the blast furnace is approximately 90 pct.…”

Experimental determination of sulphide capacities of blast furnace slags with higher MgO contents

“…The increasing demand on improvement of steel cleanness and process optimisation has drawn a great attention on the desulphurisation of hot metal before the BOF process [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. If the capacity of the blast furnace slag to capture sulphur can be optimally utilised, it would have a big impact on the process optimisation and material saving [5,6,8].…”

“…The details of the experimental setup can be found in previous publications [2,16]. As shown in Figure 1, a high temperature furnace with graphite heating element was employed.…”