SU406907A1 - - Google Patents

Description

The invention relates to the field of ferrous metallurgy, in particular, to the production of ferroalloys. The known methods of refining ferrous metals from carbon and phosphorus by treating them with slags with a high content of iron and calcium oxides are not suitable for refining ferroalloys with high salts of chromium, manganese, vanadium, titanium, and tungsten, which reduce iron from nglake to metal. In order to eliminate the above disadvantages, the metal (ferroalloy) is treated with basic slag in the presence of silicon in the amount of 10-60% by weight of the metal, and also the fact that silicon is introduced into the metal before slag processing. For the efficiency of the process, lime slag is used with SiOan-TiOg-fZrOa + AlgOs content not exceeding 40% in an amount of 0.1-6.0 by weight of the metal. The maximum effect is obtained when a melt consisting of Sar2 and Ca is introduced into the metal after its treatment with lime slag, taken in a ratio of 1: 0.5-1: 5. The molten metal is treated with a liquid basic slag without oxidation of the metal, i.e. under reducing conditions. The presence of silicon contributes to the transfer of carbon and phosphorus to the main slag. The content of iron, manganese, chromium, etc. in the slag is low and their losses from the slag are insignificant. Phosphorus and carbon dissolved in the metal interact with calcium oxide and silicon. In all processes, phosphorus and carbon are absorbed by a highly basic slag containing less than 40% Zi02 + Ti02 + Zr02 + Al2O3 in the form of calcium, barium and magnesium phosphides. Silicon reduces calcium, barium, and magnesium, which bind phosphorus in the form of phosphides. Experiments have shown that optimal conditions and dephosphorization are obtained when slag is present in an amount of 2.0-6.0 by weight of the metal. After the slag is drained in the metal, a part of phosphorus and carbon remains, therefore, to completely remove impurities, a molten slag is introduced into the metal, consisting of CaFa and Ca in a ratio of 1: 0.5-1: 5 in an amount of 0.2-0.8 from metal weight. With a decrease in the silicon content in the metal of less than 10%, the removal efficiency decreases sharply, with an increase of more than 60%, phosphorus dissolves in the alloy in the form of alkali earth metal phosphides. Example. In the ladle lined with magnesite brick, pour 2 tons of waste slag, refined ferrochrome, burning:%: CaO52,3 MgO11.5

SiOs28,2

SrgOz3,8

FeO0.75

Slag temperature is 1780 ° C. 2.8 tons of silicochrome containing 51.3% Si, 32.5% Cg, 0.022% P, 0.032% C are poured into the ladle with slag. The temperature of the metal during casting is 1620 ° C. After holding the metal and slag in the ladle for 20 minutes, the silicochrome contains 49.6% Si, 33.1% Cg, 0.008% P, 0.021% C. Thus, the carbon content is reduced by 34.3% and phosphorus by 63.6% from the initial content of these impurities in the metal.

Liquid ferromanganese is treated with molten metal Ca and Ba in an amount of 30% by weight of the alloy at a temperature of 1300 ° C. The initial ferromanganese contains 0.224% P, and after treatment with Ca and Ba, respectively, 0.0055 and 0.011% R. The degree of dephosphorization is 97.54 and 95.1%. The same initial ferromanganese is treated with molten mixtures: 50% Ca + 50% CaFg; 50% Ba + 50% BaRg.

The phosphorus content decreases from 0.224 to 0.0045 and 0.012%, i.e., by 97.9 and 94.6% of the initial (respectively).

The subject matter of the invention

The method of refining metals from carbon and phosphorus under reducing conditions by treatment with lime slag, which, in order to increase the efficiency of removing carbon and phosphorus, silicon is tentatively injected into the metal in an amount of 10-60% by weight of the metal and the treatment is carried out by continuously pouring the metal into slag to its content of ferrous oxide of 0.1-0.8%, and

calcium in the metal 0.1-5.0%.