Research on Reduction of Sulphur in Iron Melt
Abstract
Sulphur is a harmful and unwanted impurity in iron melt, and its control is a long-term task for ironmaking industry. In this paper, the reduction methods for different types of sulphur sources in iron melt are discussed. According to the different characteristics of sulphur reduction, the advantages and disadvantages of each method and their application conditions in actual production are also analyzed. With the development and utilization of new physical and chemical methods, it is proposed that the combined use of several reduction methods can effectively reduce the sulphur content in iron melt and obtain qualified iron products.
Keywords: iron melt; sulphur; reduction; physical and chemical methods
1.Introduction
Sulphur, as an undesired impurity element in iron melt, will cause environmental pollution and reduce the quality of steel products. It has become a long-term challenge for ironmaking industry to control and reduce sulphur content in iron melt continuously. Traditional reduction methods for sulphur in iron melt include mechanical desulfurization and chemical desulfurization. However, these methods have high requirements for technological conditions and cannot meet the requirements of current production. Therefore, how to improve the reduction methods for sulphur in iron melt and obtain qualified iron products has become a key issue in practice.
2.Characteristics of Sulphur Reduction in Iron Melt
Different reduction methods have different effects on different sulphur sources. Generally, there are three types of sulphur sources: sulphide ore, flux and match rod, among which sulphide ore is the main source of sulphur in iron melt. The reduction of sulphur in iron melt mainly depends on three factors: the reaction of sulphur with oxygen in iron melt, the reaction between iron and sulphur and the adsorption of iron and sulphur on the surface of solid inclusions. In the process of ironmaking, due to the great amount of sulphur, the reduction of sulphur by reaction and adsorption can hardly meet the requirements of qualified iron products. Therefore, physical and chemical methods need to be combined for sulphur reduction.
3.Sulphur Reduction in Iron Melt
(1) Mechanical desulfurization: It is the most commonly used method to reduce the sulphur content in iron melt. Through a series of processes such as aerator stirring and slag holding, the sulphur contained in the slag can be kept in the slag and discharged by the slag. However, the mechanical desulfurization method is difficult to control, and it is not suitable for large-scale reduction.
(2) Chemical desulfurization: It is a method of desulfurization that utilizes the strong reducibility of some reducing agents, such as magnesia-containing carbon-containing materials, to reduce the reaction of sulphur-bearing compounds with oxygen in iron melt and reduce their solubility. In actual production, chemical desulfurization is mostly used to reduce the sulphur content of flux and steel.
(3) Physical desulfurization: This method utilizes the hydrophobic and electrostatic effects of solid inclusions such as silicon, ferromanganese, lime and so on in iron melt, so that some sulphur-containing compounds are adsorbed on the surface of these inclusions to achieve the purpose of desulfurization.
(4) New physical and chemical methods: In recent years, with the development of new materials and their application to ironmaking, a variety of new physical and chemical desulfurization methods have been developed. These methods not only improve the reduction effect but also reduce the cost of processing. For example, the low-sulphur coil has a low content of chemical oxygen and a wide application range. With its use in production, it can effectively reduce the sulphur content of iron melt.
4.Conclusion
The sulphur content in iron melt has a great influence on the quality of metallurgical products. Therefore, the reduction of sulphur in iron melt has always been the focus of attention. At present, there are various methods to reduce sulphur in iron melt, and each has its own advantages and disadvantages. Therefore, in actual production, the combined use of multiple desulfurization methods can effectively reduce the sulphur content of iron melt and obtain qualified iron products.
