RU2002810C1 - Slag-forming composition - Google Patents

Abstract

Usage: when smelting cast iron in gas abroad in order to protect liquid metal from oxidation and increase the fluidity of metal Slag-forming mixture is blown into a gas cupola and deposited on the surface of the melt. A slag-forming mixture containing crushed limestone, coke and ferrosilicon is proposed in the following ratio of components, wt%: known to 3 - 20, ferrosycy 5 - 30, coke - the rest. 2 tab.

Description

And the acquisition is from metallurgy and can be used in the smelting of cast iron in gas cupolas.

Known slag-forming mixture used when razltzka steel in the mold, containing the following components, wt.%:

Silicate block 40-55

Fluorspar 4-10

Blast furnace slag5-U

Aluminum powder 15-20 Manganese ore 20-25

Known for the rest

A slag-forming mixture in the form of a powder in a stream of compressed air was blown into a gas cupola, deposited on the surface of liquid slag, mixed with it, increased the fluidity of acidic slag, but the liquid iron passing through the slag did not increase its fluidity, which was disadvantage of using said slag-forming mixture.

In foreign practice, the creation of a slag-forming mixture in coke-free cupola furnaces is used by water injection into the high-temperature zone of the cupola of a carbon-containing powder, mainly coke. Coke powder with a dust grain of up to 3 mm is blown through a channel in the cupola wall in a stream of compressed air. The coke powder injection site is below the tunnels of the gas burners, but above the upper level of the molten metal in the pool. Upon entering the high-temperature zone of the coke-free cupola cupola, coke powder is deposited on the surface of the slag, mixed with slag, and heated by fuel combustion products, hot slag. The resulting slag-carbon mixture partially deoxidizes and carburizes the molten iron passing through it. But with acidic slag, the liquid metal is saturated with sulfur contained in the coke powder, which reduces the liquid fluidity of the metal. In addition, the liquid metal is not sufficiently deoxidized.

The purpose of the invention is to protect the liquid metal from oxidation, to increase the fluidity of the metal.

Based on the studies, a slag-forming mixture containing crushed limestone, coke and different from the known ones was developed in that it additionally contains crushed ferrosilicon in the following ratio of components, May,%:

Known k3-20

Ferrosilicon 5-30

Coke Else

The introduction of a slag-forming mixture of the specified composition into the gas cupola ensures protection of molten iron from oxidation, and an increase in the fluidity of the metal. .

Slag-forming mixture of this composition

wa allows you to reduce the sulfur content in

metal, since the input of lime helps to increase the basicity of the slag during high alumina lining of the overheating chamber, saturate the metal with carbon from

introduced coke and silicon from the introduced ferrosilicon, Water slag-forming mixture of a new composition leads to the formation of reducing slag on the surface of the liquid metal in the overheating chamber.

Consequently, conditions are created to protect the molten metal from oxidation.

The slag-forming mixture is blown into a gas cupola and deposited on the surface of the melt. For feeding slag converters

mixtures can be used shot blasting apparatus. The selection of the shot blasting apparatus necessary to be made taking into account the small capacity for feeding the slag-forming mixture into the gas cupola "has {more than 7% of the cupola capacity for molten cast iron). It is necessary to regulate the flow of the slag-forming mixture. For this, the shot blasting machine must be equipped

metering and regulating the flow rate of the mixture device.

Table 1 shows the compositions of the mixtures, and Table 2 shows their effect on metal losses due to oxidation in a gas cupola and

the fluidity of cast iron during constant chemical composition and temperature of liquid metal t when a standard technological spiral sample is poured into the mold.

The composition of the cast iron is as follows: 3.3% carbon, 1.8% silicon, 0.4% manganese, 0.06% sulfur, 0.1% phosphorus. Liquid metal temperature t 1370 ° C. The fluidity of cast iron was characterized by the length of the cast iron cast in the form of a technological spiral sample. Cast iron was melted in a gas cupola with a remote overheating chamber with a capacity of 2 t / h.

(5G) USSR Copyright Certificate No. 1574G67, cl. C 22 C 35/00, 1988.

Germany application No. 2207502, class. C 21 C 1/08, 1973.

Table 1

Claims (1)

The claims 5 it contains SLAG-FORMING MIXTURE for the following ratio of components, work of cast iron in a gas cupola, wt.%: living ferrosilicon and coke, Known k3-20 Ferrosilicon 5-30 coke, characterized in that, in order to increase the fluidity of the metal, it is additional 10 Coke table 2 Rest