RU2471874C1 - Method of removing titanium from high-chromium melts - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: method comprises tapping metal from furnace to ladle, building CaO-SiO₂-MgO-system slag up on metal melt surface, and adding iron chloride as chlorinating agent to liquid slag. Then, melts are soaked to termination of reaction of titanium removal from metal in gas phase in the form of volatile titanium chloride. To accelerate reaction of refinement and removal of titanium chlorides from reaction zone, the melts are blown by neutral gases, for example, argon or carbon oxide.

EFFECT: higher quality and efficiency, nonpolluting process.

3 cl, 1 tbl

Description

The invention relates to the field of metallurgy of ferrous metals and can be used for refining of titanium steel and iron-based alloys, in particular for refining chromium ferroalloys with different carbon contents.

Known pyrometallurgical method for removing titanium from silicon ferroalloys by blowing gaseous chlorine in a ladle (MA Ryss. Production of ferroalloys - M .: Metallurgy, 1985, 344 pp.). In this case, liquid ferrosilicon is blown with gaseous chlorine in the ladle, which makes it possible to obtain an alloy with a content of about 0.5% Ti, regardless of its initial concentration in the ferroalloy. However, this method is cheaper than the smelting of pure ferrosilicon from highly pure materials (Gasik M.I., Lyakishev N.P., Emlin B.I. Theory and production technology of ferroalloys - M .: Metallurgy, 1988, 463 pp.).

The disadvantages of the above method of removing titanium from silicon ferroalloys by purging with gaseous chlorine include the use of expensive and toxic reagents, the difficulty of ensuring normal sanitary and hygienic conditions in industrial premises and the environmental friendliness of the production process. At the same time, the process itself provides only relatively high residual titanium concentrations in the ferroalloy of about 0.5% in comparison with modern requirements at a level of less than 0.1% of titanium in the alloy. In addition, this method of detanitizing ferroalloys is not applicable to chromium ferroalloys due to the intensive development of harmful reactions of the interaction of gaseous chlorine with the leading element of such ferroalloys chromium. This leads to non-production consumption of chlorine, and to the loss of valuable chromium in the gas phase while braking the target reaction for the removal of titanium.

The present invention is aimed at eliminating the above disadvantages.

This is achieved by the fact that when performing the method of removing titanium from high-chromium melts, a slag-forming mixture of the CaO-SiO ₂ -MgO system in the amount of 3-10% by weight of the metal and a chlorinating reagent FeCl ₃ (iron chloride) in the amount of 1 are loaded onto the surface of the metal melt in the ladle. -3% by weight of the metal while blowing the melts with argon with a flow rate of 0.2-2 m ³ / (t · min) for 10-40 minutes In this case, titanium in the form of titanium chlorides is removed from the melt into the gas phase.

The invention consists in the following.

In contrast to the prototype, instead of the chlorinating reagent - gaseous chlorine, less reactive iron chloride is used. As a result, there are no side reactions of the formation of iron chlorides, reactions of the formation of iron chlorides are absent, reactions of the formation of chromium chlorides are suppressed, and the target reaction of the formation of titanium chlorides still retains sufficient completeness. To keep volatile iron chloride on the surface of liquid ferrochrome, a slag-like mixture of the CaO-SiO ₂ -MgO system is used. Liquid slag of this composition dissolves iron chloride, thereby reducing the elasticity of the iron vapor in the system. As a result, iron chloride stays in the system for a time sufficient for the complete reaction of detanization. At the same time, purging the metal in the ladle with argon mixes the melts in the ladle, which accelerates the delivery of dissolved titanium to the reaction surface while simultaneously removing the formed titanium tetrachloride from the metal-slag system. Instead of argon gas, a non-deficient mixture of gaseous carbon monoxide CO and carbon dioxide CO ₂ with a CO / CO ₂ ratio _of at least 95/5 can be used to purge the melts to avoid oxidation of the components of ferrochrome with carbon dioxide.

Other technological operations during the implementation of the method are carried out in accordance with the known instructions in force at ferroalloy enterprises.

Table 1 shows the results of experimental swimming trunks by the proposed method. The treatment was subjected to carbon ferrochrome grade ФХ800 with the initial content of chromium 60% and titanium 0,084%. On the surface of the melt, slag of the CaO-SiO ₂ -MgO system was introduced in an amount of 10% by weight of the metal and a chlorinating reagent FeCl ₃ in the amount of 3% by weight of the metal was introduced into the slag with the melt being blown with argon at a flow rate of 0.2 m ³ / (t · min )

At the end of the purge, the titanium content in the ferrochrome melt decreased to 0.045%, which corresponds to a 46% degree of detanization, while maintaining the chromium content in ferrochrome at a level of 60%.

The chromium ferroalloys obtained using the proposed technology correspond to ferrochrome grades of the highest quality category for titanium, and the technology of extra-furnace removal of titanium is a promising and effective chlorine process, which, to a much lesser extent than, for example, purging with gaseous chlorine to remove titanium, pollutes the environment while maintaining chromium in the ferroalloy.

Thus, the proposed method for the removal of titanium from high-chromium melts is quite simple, economical and efficient.

Table 1 The dependence of the concentration of titanium in carbon ferrochrome on the processing time Melting time, min The concentration of titanium in ferrochrome [Ti],% The degree of removal of titanium R _Ti ,% 0.00 0,084 0.00 0.21 0,083 1.19 1.31 0,078 7.14 2.48 0,073 13.10 3.74 0,068 19.05 5.09 0,063 25.00 6.55 0.058 30.95 8.14 0,053 36.90 9.89 0,048 42.86 11.83 0,043 48.81 14.00 0,038 54.76 16.49 0,033 60.71 19.38 0,028 66.67 22.84 0,023 72.62 27.15 0.018 78.57 32.87 0.013 84.52 41.41 0.008 90.48

Claims (3)

1. The method of removing titanium from high-chromium ferroalloys, including the release of ferrochrome from the furnace into the ladle and guidance on the surface of the metal melt of the slag of the CaO-SiO ₂ -MgO system, characterized in that a chlorinating agent in the form of iron chloride FeCl ₃ is introduced into the liquid slag and the melts are maintained metal and slag to complete the reactions of removal of titanium from the metal into the gas phase in the form of volatile titanium chlorides. 2. The method according to claim 1, characterized in that the molten metal and slag are purged with gaseous argon with a flow rate of 0.2-2 m ³ / (t · min). 3. The method according to claim 1, characterized in that the molten metal and slag are purged with a mixture of gaseous carbon monoxide CO and carbon dioxide CO ₂ at a ratio of CO / CO _{2 of} at least 95/5 with a flow rate of 0.2-2 m ³ / (t Min).