KR820001566B1 - Blast furnace smelting of zinc - Google Patents

Abstract

A blast furnace tuyers has a main section in the form of a pipe having a central passage (1). The mouth(4) forming part of the tuyere comprises an extension to the upper pipe wall which is inclined towards its base and has a hood shape so that gas crossing the tuyere mouth is directed towards the base. The extension (2) also comprises an outlet orifice (14) for gas having a surface area greater than that of the central passage cross-section. The tuyere assists in increasing the production of carbon monoxide by increasing contact between coke and air so that zinc oxide contained in the slag and which would otherwise be lost is reduced to zinc for recovery.

Description

Blast furnace

The accompanying drawings are schematic longitudinal cross-sectional views of the furnace tufts according to the invention.

The present invention relates to a zinc smelting furnace, and more particularly to blowing into such a furnace.

Currently, smelting of zinc in blast furnaces is well known in the art, and has been put to mass production since the 1950s. (See, for example, "Smelting of Zinc in Furnaces" by Morgan and Woods, published in Metallurgioal Reviews (156), November 16, 1971).

In this method, air or oxygen-enriched air is introduced from the tuyere near the bottom, and zinc vapor-containing gas is withdrawn from the outlet near the top of the no-shaft, so that a small droplet of molten lead is sprayed. Zinc condenses from the gas in the condenser.

One problem with smelting zinc in such furnaces is the loss of zinc contained in the form of zinc oxide in the slag falling to the bottom. These slags contain about 10% zinc as zinc oxide, not to mention the overall reduction in the recovery of zinc from the oxide material charged into the furnace. Therefore, until now, various attempts have been made to reduce the loss of zinc in slag. However, the requirement that zinc oxide in other slag-forming components is easy to dissolve and requires the maximum fuel saving possible has made this difficult. Although the recovery of zinc from lead furnace slag has been limited by the slag volatilization method in which air and reducing material are blown into the molten slag of lead furnace to volatilize zinc to oxidize zinc, it is not preferable for zinc furnace slag. . This is because it requires an investment to install a separate plant and is also expensive in terms of fuel consumption.

British Patent 1458869 describes a method of reducing zinc loss in slag by blowing into slag pools from tufts inclined downwards at an angle of 12 ° to 20 ° with respect to the horizontal. This method reduces the zinc content of the slag to some extent but still requires good gas-slag contact.

In order to maximize the reduction of the zinc in the slag at the bottom, it is necessary to bring the carbon monoxide-containing gas into contact with the highly dispersed molten slag. Therefore two are required.

1. Disperse molten slag to the maximum in blowing

2. A small drop of slag is raised along the furnace opening, and then a small drop of slag falls under gravity to flow counter to the rising carbon monoxide-containing gas stream.

Carbon monoxide is produced by the reaction of carbon in slag or coke with oxygen in blowing air, or carbon dioxide and carbon in the bottom part.

The present invention provides a tuyere specially designed to increase physical contact between slag and gas.

Therefore, an object of the present invention is in the form of a tube having a central portion of the tuyere, the front end of the tuyere has an extension in the form of a hood inclined downward to the upper wall of the tube and passes through the tuyere tip The gas is inclined downward along the extension, and the gas outlet of the extension is to provide a tuyeres of the furnace having a larger cross-sectional area of the hole of the tube.

The "cross section area of the hole of the tube" herein means the area of the cut surface when the tube portion is cut in a plane perpendicular to the longitudinal side of the tube portion of the tuyere.

The extension is straight or curved in the longitudinal direction.

In the case where the extension part is straight in the longitudinal direction, the angle between the longitudinal side of the tube portion of the tuyere and the wall of the extension part is preferably in the range of 12 ° to 20 °, particularly 15 ° to 16 °. If the angle is larger than 20 °, the resistance of the gas becomes high, causing excessive pressure drop, and it is difficult to clean the air flow restriction in picking up the air flow restriction with a stick. As described in British Patent No. 1446869, it can be understood that the subjective tube portion itself of the tuyere is inclined downward at an angle of 12 ° to 20 ° with respect to the horizontal. In this case, the charge-direction inclination of the extension portion is 30 degrees or more with respect to the horizontal.

Such tuyere is produced by welding a precast cast extension to the tip of the tube.

Here, the "wall" of the tuyere is a hollow wall in which a circulation passage of a cooling fluid (usually water) is installed in the middle. This applies to both the tubular part and the extension of the tuyere. In fact, the tuyere is designed to install an annular space between the inner wall and the outer wall, in which a baffle is inserted, thus forming a cooling water passage between the baffle and the inner and outer walls.

In one preferred configuration, water passes through a baffle inserted into the hollow space between these inner and outer walls and a passage formed between the inner and outer walls, and flows longitudinally throughout the tip portion of the tuyere. This flow of water is a "malti pass" in which the incoming coolant flows through the first part of the tuyere, one third of the periphery of the tuyere, and then the water in sequence Passing through the at least one second portion and the final third portion preferably passes through the tip of the tuyere and exits the tuyere. The perimeter of the tuyere is divided into three parts by suitable partitions.

The extension of the tuyere deflects the gas passing through the tuyere tip, thereby causing turbulence and further spreading the slag when it hits the slag pool.

Another object of the present invention is to provide a zinc smelting furnace having at least one tuyere according to the present invention in which the longitudinal side of the tube portion of the tuyere is inclined downward at an angle of 12 ° to 20 ° with respect to the horizontal.

Still another object of the present invention is to blow air into the blast furnace through at least one tuyere having a main tube portion and an extension portion in the form of a downward slope of the upper wall thereof, wherein air is discharged through a hole having an area larger than the cross-sectional area of the tube. It is to provide a method of smelting zinc in the furnace.

It is well known in the furnace technology to provide a downward slope tuyere and its downward slope extension. Moreover, there is no conventional blast furnace for the furnace in which the disturbance part is provided in the front-end | tip.

Comparing the tuyere according to the invention with other curved tip tuye

(a) less pressure drop

(b) easy to clean by picking sticks to remove blockages

(c) it is easy to take out from the pit

(d) slag-gas interaction is improved.

DETAILED DESCRIPTION An embodiment of the present invention will be described below with reference to the accompanying drawings.

The depicted tuyere has a main tube part with a central hole 1 and an extension 2 in the form of a hood on the top wall. 3 and 4 show the inlet and outlet tubes of the cooling water, respectively. A blowing pipe 5 is provided in the central hole of the tuyere. At the tip of the tuyere, a baffle 6 is inserted into the annular space between the inner wall 7 and the outer wall 8 and forms passages 9 and 10 for allowing the cooling water to pass into the tip.

The coolant flowing from the inlet pipe 3 passes through the chamber 13, passes through the passages 10 and 9 through the inner surface of the tuyere inner wall, and then flows through the inner surface of the outer wall. This water flow flows in the first 1/3 of the surroundings of the tuyere. The water flowing out of this first portion passes through the septum into the surrounding second portion and this form of flow is repeated. Finally, the water is discharged from the second part and enters the surrounding third part 12, and this form of flow is repeated again, and the water circulating in the air flow finally enters the seal 11, where the discharge pipe 4 It is sent out from

The cross-sectional area of the outlet 14 of the tuyere is larger than the hole 1 of the tuyere section. Therefore, the air blown out from the pipe portion of the blower tube 5 is discharged from the outlet 14 and deflected downward to expand.

Claims (1)

As described in the text and shown in the drawings, the gas passing through the end of the tuyere is in the form of a tube having a central hole with the main part of the tuyere, and has a hood-like extension portion inclined downwardly to the upper wall of the tuyere. Is a downward deflection along the extension and the area of the gas outlet of the extension is larger than the cross-sectional area of the hole of the tube.

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