SU1730175A1 - Method of dephosphorization of high-carbon ferromanganese - Google Patents

Abstract

This invention relates to ferrous metallurgy, in particular to the production of carbon ferromanganese with a reduced phosphorus content. The aim of the invention is to increase the degree of dephosphorization and reduce the loss of manganese. The method includes the smelting of carbon ferromanganese with a silicon content of 4-10%, the production of smelting products, the removal of furnace slag, the desilication to a residual silicon concentration of 0.5-2.0% and the subsequent processing of the alloy with a dephosphorizing mixture. The method provides removal of 20-60% of phosphorus contained in carbon ferromanganese, and increases the recovery of manganese from 71.4% to 77.4%, 2 tab.

Description

This invention relates to ferrous metallurgy, in particular to the production of ferroalloys with a reduced phosphorus content.

The known method of dephosphorization of liquid ferromanganese using slag mixtures based on.

Its disadvantages are the low degree of dephosphorization, the need to smelt low- and medium-carbon manganese alloys, the obtaining of which is associated with significant losses from slag fly.

The aim of the invention is to increase the degree of dephosphorization while reducing the loss of manganese.

The goal is achieved by the fact that ferromanganese is melted with a silicon content of 4-10%, and before dephosphorization it

Bleed to a residual silicon concentration of 0.5–2%.

The choice of initial and final silicon content is due to the need to achieve a positive effect of removing phosphorus from ferromanganese.

The oxidation of ferromanganese silicon can be carried out by any technique known in metallurgy, in particular by treating the liquid metal outside the furnace with manganese ore, scale, purging with oxygen-containing gas, etc.

The effectiveness of the process of removing phosphorus from a metal is determined by the residual concentration of carbon in the alloy before it is treated with dephosphorizing mixtures. Table 1 shows the practically achieved ratio between the concentrations of silicon and carbon in ferromanganese.

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As for reducing the loss of manganese, it is due to its higher extraction into the alloy during the smelting of ferromanganese with a high content of silicon.

PRI me R. In an electric furnace, a mixture of manganese-containing flux, cast iron shavings and a reducing agent was used to produce alloys of various compositions.

The ratio between the components in the mixture was varied so that the concentration of silicon in the finished metal ranged from 4 to 10%. After the metal was released into the ladle and the main part of the slag was separated, the metal was treated in some cases with scale or manganese ore, and in others with oxygen blowing. Upon reaching the silicon content in the alloy of 0.5-2.0, slag, based on carbides and calcium fluorides, was induced on its surface. After a short soak, the entire slag was removed.

Table 2 presents the main indicators of the process, the composition of the initial and final products.

In order to obtain comparable results of the amount of the dephosphorizing mixture, the same amount (5% by weight of the metal) was introduced in each experiment with the main composition (50% CaC2 + 50% CaF2).

The results suggest that the proposed method

provides phosphorus enhancement up to 66%, contained in ferromanganese, while reducing manganese losses by 2.5-6%.

The method can be implemented, as in ferroalloy plants, producing

carbon ferromanganese, as well as in the branches of steel smelting workshops, which prepare ferroalloys for use as alloying additives.

Ф орм ул а and з о б р ё te n and

A method of dephosphorizing carbon ferromanganese, which includes melting the alloy, releasing the alloy and slag into the ladle, removing furnace slag and then processing the alloy with a dephosphorizing mixture containing alkaline earth metal carbides, characterized in that silicon 4-10% and subjected to desiliconization to a residual silicon content of 0.5-2.0%, and then treated with a dephosphorizing mixture.

Table 1

 Cc is the degree of unsaturation of the metal by carbon.

table 2

Claims (1)

15 FORMULA AND PORTRAIT The method of dephosphorization of carbon ferromanganese, including smelting the alloy, releasing the alloy and slag into the ladle, removing furnace slag and then treating the alloy with a dephosphorizing mixture containing alkaline earth metal carbides, characterized in that, in order to increase the degree of dephosphorization while reducing manganese losses, the alloy is produced with a silicon content of 4-10% and is subjected to desiliconization to residual silicon contents of 0.5-2.0%, after which it is treated with a dephosphorizing mixture.