SU804692A1 - Method of out-of-furnace treatment of cast iron - Google Patents

Description

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This invention relates to ferrous metallurgy, in particular to off-plant desulfurization and the refining of cast iron with magnesium.

There is a known method of non-treatment of pig iron, in which various reagents are used, for example, magic, which provides deep desulfurization, refining and modification of cast iron. Various methods are proposed for introducing magnesium into the liquid metal.

The proposed method relates to the processing of cast iron in various containers with dispersed powdered, granulated, granular and other magnesium.

There is a known method of non-treatment of pig iron by blowing magnesium through a submerged tuyere, which means that the blowing process is carried out at an inductance of 2.04, 5 g of magnesium per ton of pig iron per second and a rate of introduction of magnesium at 1530 m / s.

For carrying out this method, tuyeres submerged in a liquid metal are commonly used, of which the most reliable are tuyeres with an outlet broadening. A method for treating cast iron with magnesium injection is implemented in a series of

& country factories, after processing, iron is obtained that is characterized by purity by sulfur, by nonmetallic incorporation and gases.

At the same time, during the operation, it was found that of the anesthetic method has a number of disadvantages, especially in cases of large loading of cast iron in large-capacity buckets (tip

0 torpedo, cigar-shaped and others.). Thus, it was found that at a high flow rate of the jet and; 1 the magnesium particles were dropping the tuyere, the volume of the liquid metal in the form of a dense stream that evaporates B to the volume of liquid iron due to its heat is injected. Due to the non-uniform flow, there are magni and pulsations in it,

0 The process of evaporation of magnesium is uneven and unstable. Such a phenomenon is accompanied by an increased vigor of the treatment process, a decrease in the degree of assimilation of the reagent, and an intensive overgrowth of the internal cavity of the fur-1y reaction products. This suggests that the technological parameters of the magnesium supply, proposed in a known manner, do not fully correspond to the organization

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the most optimal mode of entry of magnesium into liquid iron and evaporation.

The aim of the invention is to organize a more rational thermal mode of introducing magnesium into liquid iron, reducing the turbulence of the TI treatment process and increasing the filling of the buckets with pig iron to be treated with magnesium.

This goal is achieved by the fact that the supply of magnesium into the liquid metal is carried out at a speed of 0.04-10 m / s and at a flow rate of magnesium in the range of 0.2-1.8 g / s per ton of pig iron.

The treatment of cast iron with dispersed magnesium in this method is carried out as follows.

The tuyere, through which magnesium is introduced, is immersed in molten iron in a ladle or other container. During the immersion, the gas is fed through its internal cavity, which prevents the tuyere from being filled with liquid iron. After the tuyere is immersed in the molten iron, dispersed magnesium is supplied. In this case, the dispersed magnesium is supplied at the input rate of 0.0410 m / s at a magnesium feed rate of 0.2-1.8 g / s per ton of pig iron.

The main heat source for evaporation of magnesium is the surface of the molten iron under the broadened part of the submerged cbypzvibi.

Since the injection of magnesium into the broadened part of the tuyere is carried out along a descending line, the axis of which is at an angle to the horizontal plane, which is greater than the angle of repose of dispersed magnesium, it can be moved at speeds lower than the soar speed of particles.

Pneumatic conveying of magnesium at low speeds and in a dense stream makes it possible to several times reduce the flow rate of the transporting air, i.e. reduce the loss of magnesium, oxidizing due to oxygen

The minimum pneumatic conveying speed of the dispersed material is 0.04 m / s. Speeds of 10 m / s can reach the flow of granular particles

magnesium at low air flow and when moving along the vertical channel of the tuyere, if the flow has a low particle concentration of 5-50 kg / m.

Due to this mode of supply, there are no dense flows of magnesium embedded in the liquid metal, but quiet contact of the magnesium particles with the gas-liquid metal interface occurs in the melt volume. As a result, the process of heating, melting and evaporating the magnesium particles is established, and the process of cast iron processing proceeds calmly and technologically. This does not lead to a decrease in the overgrowth of the internal cavity of the broadening part (of the Burmese through which the magnesium is supplied to the cast iron. The quieter, established nature of the introduction of magnesium purges into the liquid metal, the more relaxed nature of the pig iron processing process in the ladle increases eliminate the dangerous vibrations of the buckets and increase the degree of assimilation of the injected magnesium.

Thus, the proposed method off-treatment of cast iron with dispersed magnesium, aimed at organizing the most rational mode of magnesium input, achieved at a low particle injection rate (0.04-10 m / s) and a small feed rate of mA; rot (0.2-1, 8 g per 1 ton of pig iron), allows to reduce the rapidity of the processing process and increase the pouring of the ladle with liquid metal.

Claims (1)

Invention Formula The method of non-treatment of pig iron, which consists in injecting magnesium into the melt, characterized in that, in order to organize a rational thermal regime for the introduction of magnesium and reduce emissions, magnesium is introduced into the iron at a speed of 0.0410 m / s in an amount of O ,, 2-1 , 8 g / s per 1 ton of iron.