RU2380633C1 - Duplex-furnace for smelting of manganese alloys from ferrimanganese bases and concentrates and anthropogenic wastes of metallurgy - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: in arch of siphon there are implemented openings or windows for loading of carbon-bearing materials, partition with bottom window or windows for flow of melted slag into siphon is implemented in the form of common end wall for liquid-phase smelting shaft and siphon with electrode(s) and allows window or windows for fume extraction from under arch of siphon, located on level not higher than horizontal axis of top row of tuyeres of liquid-phase smelting shaft, siphon is outfitted by solid transverse partition, installed in its bottom part parallel to common end wall for liquid-phase smelting shaft and siphon at a distance enough for flow of required volume of slag melt from liquid-phase smelting shaft on surface of heated layer of carbon-bearing material, herewith solid transverse partition fully separates siphon from liquid-phase smelting shaft, and its top edge is located higher than horizontal axis of bottom row of tuyeres of liquid-phase smelting shaft.

EFFECT: invention provides decreasing of structure dimensions, utilising of all heat of effluent gas from siphon, decreasing of emissions amount of dioxide from siphon into environment.

1 dwg

Description

The present invention relates to the production of high-quality manganese ferroalloys from poor concentrates (such as ores, waste slag, sludge and dust), and can also be used for coke-free processing of poor manganese ores and concentrates, as well as industrial metallurgy wastes (converter dusts) , oil sludge, nodules of the sea shelf, etc.).

Traditionally around the world, for example, poor manganese-containing ores and man-made waste for ferromanganese are subsequently processed in a baking oven (a design widely known to specialists), then slag is poured into electric furnaces lined with coal blocks (Australian patent, Cl. No. 254219, 15.4, and Metallurgy Russian Railways) , 1967, No. 3), in which lead smelting.

The disadvantage of this type of equipment:

- the need to use three furnace units, in each of which a certain temperature is maintained;

- high energy consumption due to heat loss during transportation of the melts and a significant total area of the heat-conducting surfaces of the furnace units;

- low through use of manganese;

- large emissions of harmful substances (dusts, dioxides, etc.) into the environment.

Known furnace unit for the smelting of manganese ferroalloys, called in metallurgy a duplex furnace. For example, in A.S. 1038366 (MKI: C21C 5/52, published on 08.30.83, Bull. No. 32) describes a sequential scheme: loading poor manganese-containing materials into the first electric furnace, and then reloading the melting products into the next electric furnace and their subsequent melting. Due to the wide popularity of the design of electric furnaces, their description is not given here.

The disadvantages of this technical solution:

- high energy consumption (up to 1000 kWh of electricity per tonne of redistributed manganese slag);

- increased losses of manganese with associated metal (up to 20%);

- low demand for the associated metal;

- low degree of extraction of manganese from the slag in ferromanganese;

- high slag ratio.

A common drawback of both known furnace units is that these units are able to work satisfactorily (from the point of view of technical and economic indicators) only in case of preliminary preparation of the mixture (drying of sintering, briquetting, granulation, etc.);

with exact coordination of the time of loading, staying and unloading of material for each unit of the duplex process; when a complex system of gas treatment plants is included in the scheme (since the process is associated with significant emissions of finely dispersed materials and dioxides into the environment).

Known furnace units for duplex processes, such as, for example, for the processing of finely divided oxidized poor nickel-containing ores. In these units, the above disadvantages are eliminated, including the disadvantages of the above known duplex furnaces. The most progressive unit is described in RF patent No. 234888 for application No. 2006109262 dated March 24, 2006 (authors Salikhov Z.G., Schetinin A.P., Ishmetyev E.N.) on “Vanyukov’s furnace for melting materials containing colored and black metals".

This technical solution is taken as a prototype of the claimed invention as the closest in purpose and achieved positive technical results.

The prototype essentially consists of two furnace units connected in series or connected: a Vanyukov furnace and an electric arc furnace, minor structural changes of which may be required depending on the purpose of the type of duplex furnace in question and the achieved positive results.

The prototype Vanyukov’s furnace contains:

- liquid-phase smelter with coffered belts with lower and upper rows of tuyeres;

- pipes for loading the charge and removal of furnace gases on the arch and openings for the removal of liquid metal;

- inclined or stepped hearth;

- a partition with a bottom window or windows for the flow of slag melt into a siphon;

- an electrode (s) is installed on the siphon arch (s) with the possibility of movement;

- channel (s) for the release of slag and metal components of the melt from the bottom of the siphon.

The disadvantages of the prototype include:

- a large total surface area of the unit and the associated heat loss (the size of the recovery chamber is comparable or even larger than the size of the melting chamber);

- insufficient utilization of the heat of oxidation of CO gases released during the operation of the siphon in an electric arc furnace mode (to change the slag viscosity at the metal-slag separation boundary);

- a significant amount of emissions of CO (dioxide) from the siphon into the environment;

- the need for a carbon-containing material (coke or coal) upon receipt of conversion manganese slag or ferromanganese;

- a large amount of unclaimed synthetic cast iron or requiring further redistribution obtained at the first stage of smelting of manganese ferroalloys.

The purpose of the invention: the creation of a furnace unit - a duplex furnace for smelting manganese ferroalloys from poor manganese ores, concentrates and industrial wastes of metallurgy. The combination of new signs of significant improvement of the prototype gives a positive technical effect - eliminates the disadvantages of the known furnace units for smelting manganese ferroalloys.

The proposed duplex furnace for smelting manganese alloys contains a liquid phase smelter with coffered belts with lower and upper rows of tuyeres and with holes for removing gases and loading the charge and discharge of liquid metal, an inclined or stepped hearth, a partition with a lower window or windows for the release of slag melt into a siphon, on the arch of which electrode (s) are installed to control the temperature of the melt, and a channel (s) for the release of slag and metal components of the melt from its lower part.

In it, the role of the end wall of the melting shaft and siphon is played by a partition, the upper edge of which rests on the vault of the melting shaft, and the lower edge - on its bottom, the vault of the siphon, through the window (a) of the partition made (s) to remove gases from under its arch , at a level below the horizontal axis of the upper row of tuyeres of a liquid-phase melting mine, communicated with the melting mine and contains nozzles for loading carbon-containing materials (coke, coal, etc.) into the combustion zone of the arc of the electrode (s), and a solid siphon is installed in the lower part partition upper to omka which ends above the horizontal axis of the lower row of tuyeres and the lower edge rests on the hearth siphon. In parallel, a solid partition and a transverse partition with windows form a channel for melt flow from the melting zone to the surface of the carbon-containing reducing agent layer in the siphon.

In addition, the duplex furnace for smelting manganese alloys, the arch of its siphon through a partition window, which plays the role of a common end wall between the smelter and siphon with electrode (s), is in communication with the smelter below the horizontal axis of the upper row of tuyeres, for example, by 8 -12 sizes of the mouth of the tuyeres.

To confirm the achievement of the goal of obtaining positive technical effects and to prove the materiality of the distinguishing features, we describe the operation of the proposed design of a duplex furnace in the smelting of manganese alloys from poor ores and industrial wastes.

A duplex furnace for smelting manganese alloys from iron-manganese poor ores and concentrates and industrial wastes of metallurgy contains (see drawing): a coffered liquid-phase smelting mine - 1 with a body - 2 (the body is not mentioned further); tuyeres of the lower row - 3; tuyeres of the upper row - 4; vault - 6 with nozzles 7 for loading the charge for processing and nozzles - 8 for the removal of furnace gases on the arch and nozzle - 9 for the removal of liquid metal, bottom - 10 (flat, inclined, step or other shape), siphon - 11 with installed ( i) on its arch with electrode (s) - 12 for controlling the temperature of the melt and channels - 14 for the release of slag and metal component of the melt, a transverse partition - 13, the upper edge of which rests on the arch 6 of the melting shaft - 1, and the lower - on its bottom - 10; siphon vault - 14 with openings for supplying carbon-containing coal or coke (not indicated); as the end wall of the casing 2 of the melting shaft 1 and siphon 11, a partition 13 is used, having a bottom (s) window or windows 15 and a window 16 for removing furnace gases from under the siphon vault 11 into the lower zone of the upper row of tuyeres 4; the end wall of the siphon 11 is made in the form of a continuous transverse partition 17, the upper edge of which ends above the horizontal axis of the lower belt of the row of tuyeres 3, and the partition 17 itself is parallel to the transverse partition 13 with windows 15 at a distance sufficient to flow the entire volume of the melt flow from the smelting shaft 1 through the window 15 and the upper edge of the partition 17 to the surface of the layer of carbon-containing material in the siphon 11. The duplex furnace operates as follows.

The duplex furnace is heated to a certain temperature according to a predetermined time schedule. Then, molten slag (open-hearth, blast furnace or other low-melting slag) is charged with a coffered liquid-phase melting mine 1 until the level reaches the lower row of tuyeres 3. After heating of the roof 6, charge and coal are gradually fed through pipes 7, and oxygen-air-gas (methane) the mixture supplied through the lower row of tuyeres 3 and starting burners (not shown) creates a bubbling liquid-phase medium throughout the entire volume of melting mine 1. Since ferromanganese raw materials (enrichment waste, etc.), unfractionated coal, flux (to ensure the necessary viscosity of the melt) are actively mixed, the heat from the combustion of coal (and methane) is consumed to heat and melt the mixture, and products of incomplete combustion of it — carbon monoxide (CO) and H ₂ —are used as a reducing agent for oxides whose thermodynamic strength is lower than manganese oxide, i.e. those that can be restored with carbon monoxide. Manganese oxides are not reduced under these conditions. Reduced iron and phosphorus are deposited on the bottom 10 of the furnace and this alloy is in great demand by metallurgists (90% Fe, 0.5-3.0% Mn; 0.3-0.5% Si; 3.5-4.0% C; 2.5-4.0% P) continuously leaves the pipe 9 of the melting mine 1. Slag freed of impurities (iron, phosphorus, non-ferrous metals) and containing mainly manganese oxides and oxides whose thermodynamic strength is higher than that of manganese oxide (oxides of silicon, calcium, magnesium, aluminum, barium, etc.), through the lower (s) window (s) 15 of the transverse partition 13 and the upper edge of the continuous partition 17 continuously flows emitted onto the heated layer of a carbon-containing reducing agent formed by loading it through the loading nozzles 11 on the siphon vault 11. Passing through the carbon-containing layer, manganese and silicon oxides are reduced to different degrees, depending on the required nomenclature of the ferroalloy (carbon ferromanganese or silicomanganese), which is determined by the temperature, layer thickness and basicity of the final slag in siphon 11 (these parameters are supported by a high-precision automation system - not shown in the drawing). The resulting smelting products are released from the furnace simultaneously and separately. Due to the loading of the charge into the volume of the melting shaft 1, filled with finely dispersed “particles” of the melt, and the “heap” (in the form of a dense flow) movement of the charge flow with subsequent immersion in the melt in the absence of high exhaust gas velocities in the above-slag space does not create conditions for the removal of dust from a liquid phase smelter. This is confirmed by the practice of furnaces: liquid-phase melting in the processing of finely dispersed materials provides a reduction in dust removal by up to 30 times in comparison with a shaft, blast furnace or baffle furnace (s). Since the loaded manganese-containing charge is first wetted by immersing in a layer of molten slag, then it is ejected by the tuyeres of the lower row into the upper zone of the melting mine 1, the iron reduction reaction is many times more intense than in other known furnace units, and CO and Н _{2 are} separated from the recovery process in the upper zone of the mine and burned out by tuyeres of the upper row of tuyeres. In this case, the heat released during the afterburning of CO and H ₂ , coming into contact with the smallest particles of metal and slag, returns back to the liquid-phase bubbling layer.

The resulting melt of reduced oxides in the siphon 11 is discharged through the siphon nozzle (hole 14). The composition of this smelting product: 70-75% Mn, 17-20% Si, 1.5-2.5% C, 0.1-0.3% P and the rest Fe. The CO gases emitted during the production of this product are continuously discharged through window (a) 16 in the partition 13 and burn to CO ₂ (i.e., the dioxide, which is especially hazardous to the environment, disappears), and heat (approximately 30% of the heat of the furnace melting zone (by this value) it is possible to reduce the flow of coolants into the melting zone of the furnace, and due to the general degree of partition 13, 1/4 of the vertical parts of the furnace is reduced, and consequently, heat losses to the environment are reduced by the same amount) is transferred to the liquid-phase bubbling layer.

Thus, the combination of new elements and their location can increase the extraction of Fe by 30-35%, manganese by 15-25% and at the same time utilize the heat of the exhaust gases back into the processes of the duplex furnace, which also reduces energy costs by 15-25%, as well as allows you to get rid, almost completely, of especially hazardous to health dioxides.

The proposed duplex-furnace device for implementing the production method of ferromanganese or silicomanganese can be successfully used for the production of other types of ferroalloys from poor ores, ferromanganese concentrates and metallurgical waste, without the use of coke and without preliminary preparation of the processed raw materials with a loss of valuable components by 20-40% at this stage.

Claims (1)

A duplex furnace for smelting manganese alloys from iron-manganese poor ores and concentrates and industrial metallurgical waste, containing a liquid-phase smelter with coffered belts with lower and upper rows of tuyeres, with nozzles for loading the charge and removal of furnace gases on the roof and a hole for removing liquid metal, an inclined or stepped hearth, a partition with a bottom window or windows for the flow of slag melt into a siphon, on the arch of which is installed (s) electrode (s) for controlling the temperature of the melt and channel (s) For the release of slag and metal components of the melt from the bottom of the siphon, characterized in that openings or windows for loading carbon-containing materials are made in the siphon arch, a partition with a lower window or windows for the flow of slag melt into the siphon is made in the form of a common end wall for a liquid-phase melting mine and a siphon with electrode (s) and has a window or windows for the removal of gases from under the siphon vault, located (s) at a level not higher than the horizontal axis of the upper row of tuyeres of a liquid-phase melting mine, siphon sn abzhen with a continuous transverse partition installed in its lower part parallel to the common end wall for the liquid-phase smelter and siphon at a distance sufficient to flow the required volume of slag melt from the liquid-phase smelter to the surface of the heated layer of carbon-containing material, while a solid transverse partition completely separates the siphon from the liquid-phase melting shaft, and its upper edge is located above the horizontal axis of the lower row of tuyeres of the liquid-phase melting shaft.

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