RU2334925C1 - Shaft melting furnace - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention refers to metallurgy, particularly to assemblies for melting of metals. The shaft furnace consists of a shaft made in form of two truncated cones with big foundations coupled by means of a cylinder, of a device for loading of charge materials, the said device is made in form of two charging small and bigger truncated cones; the furnace also consists of a device for heating and of hearth. The ratio of diameters of the cylinder and smaller foundation of the lower cone of the shaft is 1.10-1.35. The ratio of diameters of the cylinder and the smaller foundation of the upper cone of the shaft is 1.05-1.25. The ratio of the height of the cylinder to the height of the upper and lower cones of the shaft is equal 1:(3.2-3.8):(1-1.2). The angle of tilt of the contact surface of the small and bigger loading truncated cones is 53°. The heating device is made as three plasmatrons, arranged in the dome of the furnace hearth along the radius per 120° and located at the angle of 40-50° to the axis of the furnace.

EFFECT: increased efficiency of furnace.

1 dwg

Description

The invention relates to the field of metallurgy, in particular to a device for melting metals.

Known as a prototype mine smelting furnace containing a shaft made in the form of two truncated cones, paired with a cylinder large bases, a device for loading charge materials made in the form of two loading small and large truncated cones, a device for heating, a furnace [1 ].

Significant disadvantages of this furnace are:

- low productivity of the furnace due to the low heating rate;

- unit orientation only for cast iron smelting;

- high production costs.

Also known is a shaft smelting furnace for continuous melting of cast iron, steel and non-ferrous metals, including a shaft for supplying a charge with burners for heating it to 1000 ° C, in which a crucible connected to it is installed under the shaft, communicating in its lower part with channels on the one hand, with the channel of the induction melting device, on the other hand, with a heated piggy bank, for example, induction, moreover, the channel of the induction melting device is made with an auxiliary tap hole or the channel connecting the crucible to the piggy bank, Position the higher level than the channel connecting the crucible with an induction device [2].

Significant disadvantages of this furnace are:

- low productivity of the furnace due to the low heating rate due to gas burners and induction heating, as well as irrational distribution of the flow of exhaust gases in the shaft of the furnace;

- non-universality and orientation of the unit only for cast iron smelting;

- the inability to ensure the sublimation of a number of oxide compounds (in particular zinc) and their selection for further use.

A well-known shaft furnace for smelting metals, including a shaft, a front forge with walls of the furnace piggy bank inclined to the bottom of the furnace and burners fixed in the front wall, channels are made on the bottom of the shaft connecting the shaft with the piggy bank, the axis of the burners are directed to the inclined wall, and in the furnace shaft perforated gratings are installed [3].

Significant disadvantages of this shaft furnace are:

- low efficiency of heat utilization of exhaust gases and non-use of heat from afterburning CO to CO ₂ for heating the remelted charge;

- irrational form of the shaft of the furnace, which does not allow to organize a good gas distribution of exhaust gases in the shaft of the furnace;

- the location of the hearth piggy bank on the side of the furnace shaft creates additional difficulties with the passage of the melted charge through the channel from the mine to the moneybox;

- irrational location of the burner devices and their low energy efficiency.

Also known is a shaft furnace for melting materials, mainly sodium sulfate mixed with coke, having a gas outlet, tuyeres and a hearth with tap holes, in which the hearth is equipped with a heated chamber connected by tuyeres [4].

Significant disadvantages of this shaft furnace are:

- low productivity of the furnace due to the low energy capacity of the heating sources, as well as due to the lack of use of heat of the exhaust gases;

- the inability to select sublimation products of a number of oxide materials (e.g. manganese, zinc) from the furnace shaft.

A shaft furnace is also known, made in the form of two truncated cones, conjugated by a cylinder with large bases, in which the ratio of the diameters of the cylinder and the smaller base of the lower cone is 1.12-1.29, and the diameters of the cylinder and the smaller base of the upper cone are 1.06- 1.22 [5].

Significant disadvantages of this shaft furnace are:

- low productivity of the furnace due to the low power of the burner devices;

- the impossibility of processing production waste;

- non-universality of the unit.

The desired technical results of the invention are:

- increase the productivity of the furnace;

- ensuring the versatility of the unit in the processing of waste;

- reduction of production costs.

For this purpose, a shaft melting furnace is proposed, comprising a shaft made in the form of two truncated cones, conjugated by a cylinder with large bases, a device for loading charge materials, made in the form of two loading small and large truncated cones, a device for heating, a hearth, the ratio the diameters of the cylinder and the smaller base of the lower shaft cone are 1.10-1.35, and the diameters of the cylinder and the smaller base of the upper shaft cone are 1.05-1.25, the ratio of the height of the cylinder to the height of the upper and lower mine cones is 1: (3.2-3.8): (1-1.2); the angle of inclination of the contact surface of the loading small and large truncated cones is 53 °, and the heating device is made in the form of three plasmatrons placed in the arch of the furnace hearth at a radius of 120 ° and located at an angle of 40-50 ° to the axis of the furnace.

The scheme of the inventive shaft furnace is shown in the drawing. The claimed limits are selected based on the following premises.

The shaft is made in the form of two truncated cones, conjugated by a cylinder with large bases with a ratio of cylinder diameters (D _c ) and a smaller base of the lower cone (D _nk ) 1.10-1.35, and cylinder diameters (D _c ) and a smaller base of the upper cone (D _cr) 1.05-1.25, and the ratio _(p H) of height to the height of the upper cylinder (H _VC) and lower (H _nc) of the cone is in a ratio of 1: (3.2-3.8): (1: 1,2) based on ensuring good gas permeability of a column of charge materials and ensuring their preliminary heating and recovery in the furnace shaft. Overseas values of the claimed limits lead to an increase in aerodynamic drag and, as a consequence, a disturbance in the course of the furnace with a decrease in unit productivity.

A device for loading charge materials made in the form of two loading truncated cones eliminates the emission of exhaust gases from the shaft of the furnace, while the contact surface angle (53 °) is selected based on a combination of conditions for optimal filling of the unit and tight fit of the cone to the generatrix to exclude exhaust gas emissions from the furnace.

The placement of plasmatrons along a radius of 120 ° is selected based on ensuring high-quality heating of the material and its melting, and successful melting of the material is ensured by an angle of inclination of the plasmatrons of 40-50 ° to the axis of the furnace. If the angle changes more than 50 °, the lining can be destroyed, and when the angle decreases less than 40 °, the formation of "cold zones in the furnace". The inventive shaft furnace operates as follows.

The furnace is loaded with charge materials through a device for loading charge materials into the furnace (1) and consists of two cones - the upper and the lower. The mixture is fed to the upper cone, then the cone is lowered and the mixture is poured onto the lower cone, the upper cone rises, then the lower cone is lowered and the mixture enters the furnace shaft (4). The furnace gases as a result of such loading are not "knocked out" of the furnace. The evacuation of furnace gases is carried out through three holes in the upper part of the furnace through a pipeline for the removal of furnace gases (2). If necessary, flue gases with a high CO content can be fed to the furnace hearth using a flap valve (3). In addition, it is possible to take gases at a high temperature (more than 650-700 ° C) from the furnace hearth for the operation of the selection of sublimated oxides (for example zinc, manganese). The mixture consists of oxide materials (ores, screenings, slags, sludges, etc.), fluxes (if necessary) and a coke reducing agent (or coal briquettes). When passing through the shaft of the furnace (4), the charge is heated.

The furnace has three recovery zones:

Solid-phase reduction zone at t = 600-1100 ° C (depending on the chemical composition of the material)

MeO _(tv) + {CO} → MeO _(tv) + {CO ₂ }

{H ₂ O} + C _(tv) → {H ₂ } + {CO}

MeO _(tv) + {H ₂ } → Me _(tv) + {H ₂ O}

Solid-phase reduction zone at t = 1100-1300 ° C

{H ₂ O} + C _(tv) → {H ₂ } + {CO}

MeO _(tv) + {CO} → Me _(tv) + {CO ₂ }

MeO _(tv) + {H ₂ } → Me _(tv) + {H ₂ O}

{CO ₂ } + C _(tv) → 2 {CO}

Solid-phase reduction zone at t> 1300 ° С

(MeO) + C _(tv) → [Me] + {CO}

[MeC] + (MeO) → [Me] + {CO}

The heated mixture from the mine enters the furnace hearth (6), where the melting process is carried out.

The horn is structurally composed of a refractory vault (7) and a hearth (8). In the arch (7), three plasmatrons (5) are introduced through three holes located along a radius of 120 °. For ease of melting, the angle of entry of the plasma torches can vary from 40 to 50 ° to the axis of the furnace. For convenience of repairs, the shaft of the furnace (4) can be disconnected from the furnace hearth by a shut-off device (10), as a result of which the roof of the furnace (7) and the hearth (8) can be shotcrete or repaired. During repairs, a new hearth may be installed under the shaft of the furnace. The inaccurate assembly (11) is equipped with a gate (9) for successful closure. In order to exclude the release of metal from the furnace hearth, the fully flying unit (11) is located above the lower point of the molten metal, i.e. the furnace always runs on a molten metal substrate. The melting is carried out periodically, with the metal being discharged into the ladle with slag, and the metal from the slag being separated in the ladle.

The shaft furnace is equipped with gas cleaning. Immediately after the exhaust ring (12), the gases enter the afterburning unit (13), which is a pipe-in-pipe installation where, after suction of air in the chamber, the afterburning of CO to CO ₂ occurs. Then the gases enter the refractory duct (14) and enter the deposition chamber of large particles (15). After that, the gases enter the cooler (16), which is a pipeline with a high contact surface, where the gases cool to 150 ° C. If the temperature at the outlet of the cooler is more than 150 ° C, then an additional pump is turned on - a booster (17), which “dilutes” the furnace gases with atmospheric air, as a result of which the temperature of the mixture drops to 150 ° C. Gas purification is carried out in the bag filter unit (18). To create the required vacuum, a smoke exhauster is used (19). The purified gases with a dust content of less than 5 mg / m ³ are emitted through the pipe (20) into the atmosphere.

The inventive pilot melting furnace was used in the processing of sludge and slag. So to obtain zinc oxide used the following technology. Briquettes of blast furnace slurry mixed with coke were loaded into the furnace. Sublimation of zinc was carried out in the furnace of the furnace, where the selection of gases was carried out. The furnace gases were purified according to the claimed scheme, as a result of which the ZnO content in the dust collected on the bag filters changed from 89 to 92%. Moreover, the resulting alloy contained 4.1-4.6% C; 0.30-0.80% Mn; 0.30-0.50% Si and was used for shaped iron castings.

In the redistribution of slag in electric steelmaking, the selection of gases was carried out through the upper part of the furnace shaft. The resulting alloy contained 3.8-4.2% C; 0.40-0.90% Mn; 0.38-0.64% Si.

The productivity of the furnace compared with the cupola unit has increased 1.7-2.4 times, the inventive furnace allows the remelting of metallurgical waste (slag, sludge) without additional coke consumption, the cost of producing an alloy is reduced by an average of 16.48 rubles per ton of alloy .

Information sources

1. Leonidov N.K. The construction and equipment of blast furnaces. - M .: Metallurgizdat, 1955 .-- 400 p.

2. A.S. USSR No. 206607, class F27B 1/02.

3. A.S. USSR No. 389375, class F27B 1/00.

4. A.S. USSR No. 381.853, class F27B 1/00.

5. A.S. USSR No. 1332124, cl. F27B 1/00.

Claims (1)

A shaft smelting furnace comprising a shaft made in the form of two truncated cones, conjugated by a cylinder with large bases, a device for loading charge materials, made in the form of two loading small and large truncated cones, a heating device, a furnace, characterized in that the ratio of diameters the cylinder and the smaller base of the lower shaft cone is 1.10-1.35, and the diameters of the cylinder and the smaller base of the upper shaft cone is 1.05-1.25, the ratio of the height of the cylinder to the height of the upper and lower cone s of the mine is 1: (3.2-3.8) :( 1-1.2), the angle of inclination of the contact surface of the loading small and large truncated cones is 53 °, and the heating device is made in the form of three plasmatrons placed in the arch the furnace hearth is at a radius of 120 ° and located at an angle of 40-50 ° to the axis of the furnace.