CN118048516A - Chromite smelting method and equipment - Google Patents
Chromite smelting method and equipment Download PDFInfo
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- CN118048516A CN118048516A CN202410184523.XA CN202410184523A CN118048516A CN 118048516 A CN118048516 A CN 118048516A CN 202410184523 A CN202410184523 A CN 202410184523A CN 118048516 A CN118048516 A CN 118048516A
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- chromite
- molten pool
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- 238000003723 Smelting Methods 0.000 title claims abstract description 109
- 238000000034 method Methods 0.000 title claims abstract description 42
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 55
- 239000001301 oxygen Substances 0.000 claims abstract description 55
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 55
- 239000002893 slag Substances 0.000 claims abstract description 52
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 44
- 229910000604 Ferrochrome Inorganic materials 0.000 claims abstract description 39
- 239000003546 flue gas Substances 0.000 claims abstract description 37
- 239000000446 fuel Substances 0.000 claims abstract description 29
- 239000003245 coal Substances 0.000 claims abstract description 25
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 20
- 239000007789 gas Substances 0.000 claims abstract description 19
- 239000002994 raw material Substances 0.000 claims abstract description 18
- 239000000571 coke Substances 0.000 claims abstract description 12
- 238000007664 blowing Methods 0.000 claims abstract description 11
- 238000005507 spraying Methods 0.000 claims abstract description 7
- 239000007921 spray Substances 0.000 claims description 45
- 239000002918 waste heat Substances 0.000 claims description 22
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical group [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 19
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 16
- RHZUVFJBSILHOK-UHFFFAOYSA-N anthracen-1-ylmethanolate Chemical compound C1=CC=C2C=C3C(C[O-])=CC=CC3=CC2=C1 RHZUVFJBSILHOK-UHFFFAOYSA-N 0.000 claims description 11
- 239000003830 anthracite Substances 0.000 claims description 11
- 238000002485 combustion reaction Methods 0.000 claims description 11
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 11
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 10
- 238000011084 recovery Methods 0.000 claims description 10
- 229910052799 carbon Inorganic materials 0.000 claims description 9
- 239000000395 magnesium oxide Substances 0.000 claims description 8
- 229910002091 carbon monoxide Inorganic materials 0.000 claims description 7
- 239000003034 coal gas Substances 0.000 claims description 6
- 238000007599 discharging Methods 0.000 claims description 6
- 239000001095 magnesium carbonate Substances 0.000 claims description 6
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 claims description 6
- 235000014380 magnesium carbonate Nutrition 0.000 claims description 6
- 229910000021 magnesium carbonate Inorganic materials 0.000 claims description 6
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 6
- 239000001569 carbon dioxide Substances 0.000 claims description 5
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 5
- 239000010453 quartz Substances 0.000 claims description 5
- -1 cobble Substances 0.000 claims description 4
- 239000010931 gold Substances 0.000 claims description 4
- 229910052737 gold Inorganic materials 0.000 claims description 4
- 239000010439 graphite Substances 0.000 claims description 4
- 229910002804 graphite Inorganic materials 0.000 claims description 4
- 235000019738 Limestone Nutrition 0.000 claims description 3
- 239000002802 bituminous coal Substances 0.000 claims description 3
- 239000010459 dolomite Substances 0.000 claims description 3
- 229910000514 dolomite Inorganic materials 0.000 claims description 3
- 239000000295 fuel oil Substances 0.000 claims description 3
- 239000003502 gasoline Substances 0.000 claims description 3
- 239000001257 hydrogen Substances 0.000 claims description 3
- 229910052739 hydrogen Inorganic materials 0.000 claims description 3
- 239000003077 lignite Substances 0.000 claims description 3
- 239000006028 limestone Substances 0.000 claims description 3
- 239000003345 natural gas Substances 0.000 claims description 3
- 239000004575 stone Substances 0.000 claims description 3
- 239000002699 waste material Substances 0.000 claims description 3
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 2
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 2
- 239000004571 lime Substances 0.000 claims description 2
- 230000001105 regulatory effect Effects 0.000 claims description 2
- 238000005516 engineering process Methods 0.000 abstract description 13
- 239000000843 powder Substances 0.000 abstract description 13
- 230000007547 defect Effects 0.000 abstract description 5
- 230000001419 dependent effect Effects 0.000 abstract description 4
- 238000001035 drying Methods 0.000 abstract description 4
- 238000000227 grinding Methods 0.000 abstract description 4
- 238000005453 pelletization Methods 0.000 abstract description 4
- 239000000428 dust Substances 0.000 description 24
- 239000000779 smoke Substances 0.000 description 21
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 12
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 12
- 229910052804 chromium Inorganic materials 0.000 description 12
- 239000011651 chromium Substances 0.000 description 12
- 238000010248 power generation Methods 0.000 description 11
- 229910045601 alloy Inorganic materials 0.000 description 10
- 239000000956 alloy Substances 0.000 description 10
- 238000005265 energy consumption Methods 0.000 description 9
- 239000000463 material Substances 0.000 description 9
- 239000004744 fabric Substances 0.000 description 7
- 229910052742 iron Inorganic materials 0.000 description 6
- 230000001502 supplementing effect Effects 0.000 description 6
- 239000002245 particle Substances 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 239000012159 carrier gas Substances 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 239000002817 coal dust Substances 0.000 description 3
- 239000003517 fume Substances 0.000 description 3
- 229910052500 inorganic mineral Inorganic materials 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 235000010755 mineral Nutrition 0.000 description 3
- 239000011707 mineral Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 230000000630 rising effect Effects 0.000 description 3
- 239000000377 silicon dioxide Substances 0.000 description 3
- 125000004432 carbon atom Chemical group C* 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000000498 cooling water Substances 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 125000004430 oxygen atom Chemical group O* 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 241001062472 Stokellia anisodon Species 0.000 description 1
- 239000011449 brick Substances 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 150000001844 chromium Chemical class 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 238000010405 reoxidation reaction Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/02—Roasting processes
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/52—Manufacture of steel in electric furnaces
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Mechanical Engineering (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
The invention discloses a chromite smelting method and equipment, wherein the method comprises the following steps: adding raw materials containing chromite, a reducing agent and a slag former into smelting equipment for smelting in a high-temperature molten pool, and spraying oxygen-enriched air and fuel into the molten pool by side blowing to burn and supply heat to the molten pool to obtain ferrochrome, slag and flue gas; oxygen-containing gas is conveyed to the upper part of the molten pool to burn with reducing gas in the flue gas, and the heat of the molten pool is supplemented. The ferrochrome powder ore or lump ore is directly smelted in the furnace without pretreatment, so that the procedures of fine grinding, pelletizing, drying and prereduction are omitted, and the treatment process flow is short. The method does not use electric energy as an energy source, solves the defect that chromite smelting is simply dependent on electric energy, and reduces the cost. The technology adopts coal as a reducing agent, and solves the defect of high price of coke used in the traditional technology.
Description
Technical Field
The invention relates to the technical field of metallurgy, in particular to a chromite smelting method and equipment.
Background
Chromium is an important strategic metal resource, belongs to one of 24 strategic mineral resources specified in national mineral resource planning (2016-2020), is mainly distributed in south Africa, zimbabwe, kazakhstan and other places in the world, and is relatively deficient in ferrochrome resources in China, and has external dependence of over 99 percent. About 90% of chromium ore is used for producing ferrochrome, about 5% is used for refractory materials, and about 5% is used for chemical chromium salt raw materials such as military industry, coating and the like.
At present, the technology for smelting the ferrochrome by the chromite mainly comprises a prereducing-electric furnace smelting technology, mainly comprises rotary kiln-electric furnace, shaft furnace-electric furnace and blast furnace smelting technology, wherein most of the chromite is fine ore after mineral separation, and the ferrochrome can be obtained by a plurality of working procedures of fine grinding, pelletizing, drying, prereducing, electric furnace smelting and the like. The power supply of each ton of ferrochrome needs to be more than 3000 degrees, the smelting process is seriously dependent on electric energy, and coke is also needed in the electric furnace smelting process.
The smelting of the ferrochrome in the prior art has long flow and large occupied area, and particularly depends on electric energy seriously. The method has a serious influence on ferrochrome smelting site selection, the chromium in China has extremely high external dependence, and enterprises also have to build power plants when constructing factories in foreign mines, so that the investment of fixed assets is huge. And the capability of treating ores per day of the unit hearth area of electric furnace smelting is limited to 2-8 t/d. Therefore, there is a need to develop a chromite smelting method and apparatus that does not rely on electrical energy and coke to reduce investment.
Disclosure of Invention
The invention provides a chromite smelting method and equipment for solving the problems of large investment, high energy consumption and high smelting cost caused by depending on electric energy and coke in the conventional chromite smelting. The above object can be achieved by the following technical scheme:
A chromite smelting method comprises the following steps:
Adding raw materials containing chromite, a reducing agent and a slag former into smelting equipment for smelting in a high-temperature molten pool, and spraying oxygen-enriched air and fuel into the molten pool by side blowing to burn and supply heat to the molten pool to obtain ferrochrome, slag and flue gas;
Oxygen-containing gas is conveyed to the upper part of the molten pool to burn with reducing gas in the flue gas, and the heat of the molten pool is supplemented.
Optionally, the chromite is non-pretreated fine ore or lump ore and is directly added into smelting equipment.
The invention directly feeds the fine ore or lump ore into the furnace for smelting, and omits the working procedures of fine grinding, pelletizing, drying, pre-reduction and the like. Oxygen-enriched air and fuel are blown into a molten pool to form strong stirring on the molten pool, and the treatment capacity and the reaction efficiency are high. The energy source is that materials such as coal dust and the like and oxygen-enriched air are directly combusted in slag to release heat, and electric energy is not used as the energy source, so that the defect that chromite smelting is purely dependent on electric energy is overcome.
Optionally, the reducing agent is a carbon-based reducing agent;
Optionally, the carbon-based reducing agent is at least one selected from anthracite, bituminous coal, lignite, coke, graphite, semi-coke and waste carbon electrode;
optionally, the carbon-based reducing agent is anthracite;
Optionally, the weight ratio of the reducing agent to chromite is 1-5:10.
The invention can adopt coal as the reducing agent, and solves the problems that the prior art needs to use a large amount of coke with high price and high pollution in the production process.
Optionally, the slag former is at least one of magnesite, quartz stone, dolomite, limestone, cobble, magnesia, quartz and lime;
Preferably, slag type MgO/Al 2O3 =0.5-1.5 is controlled by a slag former in the high-temperature molten pool smelting, and the ternary alkalinity of slag is 0.5-2.
Optionally, the volume fraction of oxygen in the oxygen-enriched air is 30% -99%;
Optionally, the fuel is at least one selected from pulverized coal, natural gas, coal gas, coke powder, graphite powder, heavy oil, gasoline, coal gas, hydrogen, granular coal and graphite particles;
Optionally, the ratio of oxygen to fuel in the oxygen-enriched air is adjusted in the high-temperature molten pool smelting process to ensure that the molar ratio of carbon dioxide to carbon monoxide generated by combustion is 0-1: 10. thus, the strong reducing atmosphere in the slag can be ensured, and the re-oxidation of the reduced metallic iron and chromium is avoided. For example, pulverized coal is used as fuel, the ratio of carbon atoms in the pulverized coal to oxygen atoms in the oxygen-enriched air should be adjusted to about 1:1, most or all of the fuel after combustion can be carbon monoxide, and no carbon dioxide is generated basically.
Optionally, the smelting temperature is 1500-1850 ℃;
optionally, the smelting temperature is 1600-1780 ℃.
Optionally, the oxygen-containing gas is air or oxygen-enriched air;
Optionally, the oxygen content in the oxygen-containing gas is 21% -99%.
Optionally, in the smelting process, the negative pressure of a hearth in the smelting equipment is-5 Pa to-200 Pa.
In the prior art, positive pressure is generally adopted, and negative pressure of a hearth is-5 Pa to-200 Pa, so that no carbon monoxide is leaked in the smelting process without sealing a furnace body and a charging system, the surrounding environment of the smelting furnace is good, and safety accidents are avoided.
The invention also provides
A chromite smelting apparatus, comprising:
The smelting furnace body is used for smelting raw materials;
The first spray gun is arranged at the lower part of the smelting furnace body, and a spray gun port is immersed in slag and is used for spraying oxygen-enriched air and fuel into a molten pool for combustion;
The second spray gun is arranged at the upper part or the furnace top of the smelting furnace body and is used for conveying oxygen-containing gas to the upper part of the molten pool and burning reducing gas in the flue gas;
the flue gas discharge port is arranged at the top of the smelting furnace body and is used for discharging flue gas in the smelting furnace body;
The slag-gold discharge port is arranged on the side wall of the lower part of the smelting furnace body.
Optionally, the chromite smelting equipment further comprises a waste heat recovery device for recovering waste heat of the flue gas. The recovered waste heat can be used for power generation or other purposes, and the comprehensive energy consumption is reduced by 10% -25% compared with the prior art.
Optionally, the chromite smelting equipment further comprises a raw material inlet, wherein the raw material inlet is arranged at the top of the smelting furnace body and is used for adding raw materials into the smelting furnace body;
Preferably, the number of the first spray guns is 2-100; the number of the second spray guns is 1-20.
The first spray gun is 1/100-99/100 of the slag layer in height, the spray gun opening is immersed in slag, and fuel and oxygen-enriched air are directly sprayed into the slag layer.
The reducing agent can be added into the molten pool in a lump or granule form (granularity is more than 1 mm) through a furnace top charging hole, and can also be finely ground into powder, and the powder is directly injected into a slag layer through a first spray gun.
Chromite and slag former can be added through a furnace top charging port, can be added to the surface of a molten pool or the molten pool through a second spray gun arranged at the furnace top, and can be directly sprayed into the molten pool through a first spray gun.
Optionally, the slag-metal discharge port is arranged at the side part of the furnace body and slightly higher than the furnace bottom, and slag and metal can be discharged together. The slag hole and the alloy hole can be arranged for separate discharge, the slag hole is arranged on the slag layer, the alloy hole is arranged on the alloy layer, and the discharge can be continuous by adopting a siphon hole and can be intermittent.
The technical scheme of the invention has the following advantages:
In the method, ferrochrome powder ore or lump ore is directly smelted in a furnace without pretreatment, so that the procedures of fine grinding, pelletizing, drying and prereduction are omitted, and the treatment process flow is short; the energy source is that materials such as coal dust and the like and oxygen-enriched air are directly combusted in slag to release heat, and meanwhile, the high-efficiency high-smelting-strength high-melting-efficiency high-melting-furnace is used for stirring a molten pool vigorously, and strong reducing gas overflowed from the molten pool is combusted to supplement heat for a melt, so that the fuel utilization rate is improved. The method does not use electric energy as an energy source, solves the defect that chromite smelting is simply dependent on electric energy, and reduces the cost. The technology adopts coal as a reducing agent, and solves the defect of high price of coke used in the traditional technology. The method for treating chromite to smelt ferrochrome has high smelting strength and 5-10 times of the treating capacity of the traditional submerged arc furnace; compared with the prior art, the comprehensive energy consumption for treating chromite is reduced by 10-25%.
The device has the advantages of short flow, low cost, low energy consumption, environmental protection, side-blowing waste heat power generation, no need of external electric energy, independent factory building, no dependence on external social infrastructure conditions, and low requirements on the process factory building conditions and flexible site selection, and is particularly suitable for underdeveloped areas of electric power system infrastructures. Low investment cost, short process flow, low comprehensive energy consumption, high efficiency, high smelting strength and environmental protection. The recovered waste heat can be used for power generation or other purposes, and the comprehensive energy consumption is reduced by 10% -25% compared with the prior art. Can be widely applied to upgrading and reconstruction of ferrochrome smelting new enterprises or old enterprises.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of the present invention;
FIG. 2is a schematic view of the structure of the smelting apparatus of the present invention.
Detailed Description
Various exemplary embodiments of the invention will now be described in detail, which should not be considered as limiting the invention, but rather as more detailed descriptions of certain aspects, features and embodiments of the invention. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
In addition, for numerical ranges in this disclosure, it is understood that each intermediate value between the upper and lower limits of the ranges is also specifically disclosed. Every smaller range between any stated value or stated range, and any other stated value or intermediate value within the stated range, is also encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention.
As used herein, the terms "comprising," "including," "having," "containing," and the like are intended to be inclusive and mean an inclusion, but not limited to.
The invention provides a chromite smelting method, as shown in figure 1, comprising the following steps:
Raw material preparation and batching: the granularity of the charging materials of ferrochrome ore or lump ore, slag forming agent and reducing agent (when the charging agent is added at the charging port at the furnace top) is less than 50mm, the water content is less than 10%, and the charging materials are added into the reinforced molten pool smelting furnace through a belt according to the batching scheme according to metallurgical calculation; the slag former is one or more selected from magnesite, quartz stone, dolomite, limestone and the like, and slag type MgO/Al 2O3 =0.5-1.5 is controlled, and the ternary alkalinity is 0.5-2. The materials are added through the charging ports arranged on the furnace top, and the number of the charging ports is 1-20.
Side-blowing oxygen-enriched air and fuel into a molten pool for combustion, smelting raw materials, adding the raw materials into a furnace, directly entering the vigorously stirred molten pool, and rapidly completing melting, slagging, reaction and slag-gold separation in the molten pool; slag and ferrochrome are separated, alloy is settled into the bottom, a bottom alloy layer is formed by a molten pool in the furnace, and a slag layer is formed on the upper part.
Wherein the smelting temperature of the molten pool is 1500-1850 ℃, the preferable temperature range is 1600-1780 ℃, the reducing agent can be anthracite, bituminous coal, lignite, coke, graphite, semi-coke, waste electrode and other carbon-containing materials, the reducing agent can be added into the molten pool through a charging hole at the top of the furnace in a block shape or a particle shape (the particle size is more than 1 mm), or can be finely ground into powder or a particle shape less than 5mm, and the powder or the particle shape can be directly blown into the molten pool by a first spray gun in a side blowing way.
Oxygen and fuel injected into the furnace burn, and in order to ensure a strong reducing atmosphere in the slag and avoid reoxidation of reduced metallic iron and chromium, most or all of the combustion should be made to generate carbon monoxide, and the carbon dioxide generation amount is less than 10% of the carbon monoxide. For example, pulverized coal is used as fuel, the ratio of carbon atoms in the pulverized coal to oxygen atoms in the oxygen-enriched air should be adjusted to about 1:1, most or all of the carbon monoxide is generated by burning, and no carbon dioxide is generated basically.
The top or side wall of the upper part of the molten raw material is provided with a second spray gun for spraying air or oxygen-enriched air (the oxygen-enriched concentration is 22% -99%), strong reducing gas overflowed from a molten pool is combusted, the heat is supplemented to the vigorously stirred molten pool, the heat supplementing efficiency is 40% -80%, reducing gas overflowed from the molten pool such as CO is combusted, and the combustion proportion is 50% -100%.
Oxygen-enriched air and fuel are injected, the oxygen concentration of the oxygen-enriched air is 50% -99%, and the fuel can be pulverized coal, natural gas, coal gas, coke powder, graphite powder, heavy oil, gasoline, coal gas, hydrogen and the like; the first spray gun is 1/100-99/100 of the slag layer in height, the spray gun opening is immersed in slag, and fuel and oxygen-enriched air are directly sprayed into the slag layer.
The negative pressure of a hearth in the side blowing furnace is-5 Pa to-200 Pa, the negative pressure is regulated according to a furnace structure, the flue gas is easy to leak from a charging port due to the excessively low negative pressure, the heat supplementing effect of secondary combustion on a molten pool is poor due to the excessively high negative pressure, and the temperature of discharged flue gas is high.
After the smoke after burning and supplementing heat is discharged out of the furnace, air is blown into the rising flue in a forced way, the temperature of the smoke and dust is reduced to 1000-1500 ℃, the cooled smoke and dust enters a waste heat recovery device to recover waste heat, and steam is used for power generation or other purposes and is collected by a cloth bag. The temperature of the flue gas and smoke dust discharged from the waste heat recovery system is reduced to 350 ℃, the temperature is reduced to below 200 ℃ through a surface cooling flue, and the obtained smoke dust is returned to the system after the smoke dust is collected through a cloth bag. The flue gas is treated to reach the discharge standard.
The scheme belongs to a ferrochrome smelting method and a device, wherein ferrochrome is smelted in a reinforced molten pool smelting furnace, and the recovery rate of iron and chromium respectively reaches more than 98 percent and more than 95 percent; the products are ferrochrome, smelting tailings, flue gas and smoke dust, and the smoke dust is collected and returned to the system to enter the furnace again for smelting.
A chromite smelting apparatus as shown in figure 2, comprising:
a smelting furnace body 1 for smelting raw materials;
The first spray gun 2 is arranged at the lower part of the smelting furnace body and is immersed in slag, and is used for spraying oxygen-enriched air and fuel into a molten pool for combustion; the number of the first spray guns is 2-100.
The second spray gun 3 is arranged at the upper part of the smelting furnace body, and is used for conveying oxygen-containing gas to the upper part of the molten pool and burning reducing gas in the flue gas; specifically, 1 to 20 second spray guns can be arranged on the furnace top at the upper part of the molten pool or the slag layer at the side part of the furnace body to spray air or oxygen-enriched air.
The flue gas discharge port 5 is arranged at the top of the smelting furnace body and is used for discharging flue gas in the smelting furnace body; the fume exhaust port is arranged at one end of the furnace body in the length direction, and the temperature of fume and dust of the discharged fume is 1600-1800 ℃. After the flue gas exits the furnace, air is blown into the rising flue gas by force, all the unburned CO is completely combusted in the rising flue gas or in the secondary combustion chamber and cooled to 1000-1500 ℃, the cooled flue gas and smoke enter a waste heat recovery device to recover waste heat, and the steam is used for power generation or heating and cloth bag dust collection. The temperature of the flue gas and smoke dust discharged from the waste heat recovery system is reduced to 350 ℃, and after the surface is cooled, the obtained smoke dust is collected by a cloth bag, and the obtained smoke dust is returned to the system. The flue gas is treated to reach the discharge standard.
And a slag-gold discharge port 4 which is arranged on the side wall of the lower part of the smelting furnace body. Slag is discharged together with the alloy and separated in the ladle; two discharge ports can be respectively arranged at the bottom and the middle, alloy and slag can be respectively discharged, materials are continuously added in the smelting process, and slag and alloy are intermittently discharged or continuously discharged in a siphon mode. If a discharge port is arranged, the discharge port is arranged at one end far away from the charging port; if two discharge ports are arranged, the slag discharge port is arranged at one end far away from the charging port.
The raw material inlet is arranged at the top of the smelting furnace body and is used for adding raw materials into the smelting furnace body;
the side-blown converter body is rectangular, the first spray guns are arranged on two sides of the length direction, and the second spray guns are arranged on two sides of the length direction if arranged on the side wall, and can also be arranged at the top of the furnace;
The side part of the smelting furnace body is provided with a copper cooling water jacket, refractory bricks are lined, and slag can be hung on the cooling water jacket.
The first spray gun can adopt a single-channel spray gun, a double-channel spray gun or a multi-channel spray gun; the second spray gun adopts a single-channel spray gun or a double-channel spray gun;
The smelting equipment can also be combined to adopt a pre-reduction furnace kiln (rotary kiln, shaft furnace) +reinforced molten pool smelting furnace, a pre-reduction furnace kiln (rotary kiln, shaft furnace) +reinforced molten pool smelting furnace+submerged arc furnace (direct current furnace, alternating current furnace), a side-blowing smelting furnace+side-blowing reducing furnace, a side-blowing smelting furnace+side-blowing reducing furnace+submerged arc furnace (direct current furnace, alternating current furnace) and the like according to the process production requirement, the process arrangement mode is flexible, the ladle or hot slag chute conveying can be adopted, and the oxidation or reduction atmosphere in the furnace kiln can be controlled according to the requirement in different working sections.
In addition, chromite and slag forming agent can be added through a charging port at the furnace top, can be added to the surface of a molten pool or the molten pool through a second spray gun arranged at the furnace top, and can be directly sprayed into the molten pool through a first spray gun.
The ferrochrome ore powder composition treated in each example is shown in Table 1
TABLE 1 ferrochrome ore composition
Example 1
The ferrochrome ore shown in table 1 is adopted, ferrochrome ore powder with 8 percent of water, anthracite, silica and magnesite with granularity less than 30mm are added into a furnace from a furnace top feed port through a belt, the smelting temperature of a molten pool is 1700 ℃, pulverized coal is used as fuel, the oxygen enrichment concentration of oxygen enriched air is 80 percent, a second spray gun is uniformly arranged on the furnace top, and the oxygen enrichment concentration is 30 percent. MgO/Al 2O3 =1, ternary alkalinity is 1.2, air is used as carrier gas to blow fuel coal powder into slag through a first spray gun, 80% oxygen-enriched air 1385.8Nm 3 is consumed per ton of ferrochrome alloy, anthracite is 0.488t, 1.1t of coal powder, iron and chromium content in smelting slag is reduced to 1.5% and 3% respectively, and chromium content of produced ferrochrome alloy is 50.05%. The flue gas overflowed from the molten pool is combusted in the hearth through the second spray gun, the heat supplementing efficiency of the molten pool is 65%, the temperature of flue gas and smoke dust discharged from the furnace is 1650 ℃, forced air is blown through the flue to be reduced to 1300 ℃, the flue gas and smoke dust enter the waste heat recovery device to recover waste heat, steam is used for power generation or heating, and the smoke dust obtained through cloth bag dust collection is returned to the system. And discharging the produced ferrochrome and tailings through a bottom discharge port, and clarifying and separating in a ladle.
6 Ten thousand t wet-base chromite is treated in one year, the unit hearth area treatment capacity is 21t/d, the annual consumption of reduction coal 13438t and the annual consumption of fuel pulverized coal 30175t are adopted, the grade of the produced ferrochrome 27432t is consistent with that of the conventional technology, the waste heat is comprehensively recovered, the power generation or steam is comprehensively recovered, the whole plant is satisfied, other products are sold, and the comprehensive energy consumption is reduced by 18.1 percent compared with that of the conventional technology.
Example 2
The ferrochrome ore shown in table 1 is adopted, ferrochrome ore powder with 8 percent of water, anthracite, silica and magnesite with granularity less than 30mm are added into a furnace through a belt from a furnace top feed port, the smelting temperature of a molten pool is 1730 ℃, pulverized coal is used as fuel, the oxygen-enriched air is enriched in oxygen by 95 percent, a second spray gun is uniformly arranged on the furnace top, and the oxygen-enriched concentration is sprayed by 30 percent. MgO/Al 2O3 =1, the ternary alkalinity is 1.2, the air is used as carrier gas to blow fuel coal dust into slag through a first spray gun, each ton of ferrochrome consumes 95% oxygen-enriched air 1106.8Nm 3, anthracite is 0.49t, pulverized coal is 1.03t, the iron and chromium contents in smelting slag are respectively reduced to 1.3% and 2.5%, and the chromium content of the produced ferrochrome is 50.30%. The flue gas overflowed from the molten pool is combusted in the hearth through the second spray gun, the heat supplementing efficiency of the molten pool is 65%, the temperature of flue gas and smoke dust discharged from the furnace is 1650 ℃, forced air is blown through the flue to be reduced to 1300 ℃, the flue gas and smoke dust enter the waste heat recovery device to recover waste heat, steam is used for power generation or heating, and the smoke dust obtained through cloth bag dust collection is returned to the system. And discharging the produced ferrochrome and tailings through a bottom discharge port, and clarifying and separating in a ladle.
6 Ten thousand t wet-base chromite is treated in one year, the unit hearth area treatment capacity is 25t/d, the annual consumption of reduction coal 13608.52t and the annual consumption of fuel pulverized coal 28801.7t are carried out, the grade of the produced ferrochrome is 27753t which is slightly higher than that of the conventional technology, the waste heat is comprehensively recovered, the power generation or steam is comprehensively recovered, other sales are carried out except the whole factory use is satisfied, the comprehensive energy consumption is reduced by 19.2 percent compared with the conventional technology, and the external electric energy is not required.
Example 3
The ferrochrome ore shown in table 1 is adopted, ferrochrome ore powder with 8% of water content, silica with granularity less than 30mm and magnesite are added into a furnace from a furnace top feed port through a belt, anthracite is blown into a molten pool through a spray gun, the smelting temperature of the molten pool is 1650 ℃, pulverized coal is used as fuel, oxygen enriched air is enriched in oxygen concentration of 95%, a second spray gun is uniformly arranged on the furnace top, and oxygen enriched concentration is blown in 30%. MgO/Al 2O3 =1, the ternary alkalinity is 1.2, the air is used as carrier gas to blow fuel coal powder into slag through a first spray gun, each ton of ferrochrome consumes 70% oxygen-enriched air 1665.6Nm 3, anthracite is 0.489t, the pulverized coal is 1.16t, the iron and chromium contents in the smelting slag are respectively reduced to 2% and 3.5%, and the chromium content of the produced ferrochrome is 50.09%. The flue gas overflowed from the molten pool is combusted in the hearth through the second spray gun, the heat supplementing efficiency of the molten pool is 65%, the temperature of flue gas and smoke dust discharged from the furnace is 1650 ℃, forced air is blown through the flue to be reduced to 1300 ℃, the flue gas and smoke dust enter the waste heat recovery device to recover waste heat, steam is used for power generation or heating, and the smoke dust obtained through cloth bag dust collection is returned to the system. And discharging the produced ferrochrome and tailings through a bottom discharge port, and clarifying and separating in a ladle.
6 Ten thousand t wet-base chromite is treated in one year, the unit hearth area treatment capacity is 18t/d, the annual consumption of reduction coal 13258.38t and the annual consumption of pulverized coal 31456.05t are carried out, the produced ferrochrome 27063t is slightly higher than that of the conventional technology, the waste heat is comprehensively recovered, the power generation or steam is comprehensively recovered, the whole plant is satisfied, other products are sold, and the comprehensive energy consumption is reduced by 15.6 percent compared with that of the conventional technology.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the invention.
Claims (10)
1. The chromite smelting method is characterized by comprising the following steps of:
Adding raw materials containing chromite, a reducing agent and a slag former into smelting equipment for smelting in a high-temperature molten pool, and spraying oxygen-enriched air and fuel into the molten pool by side blowing to burn and supply heat to the molten pool to obtain ferrochrome, slag and flue gas;
Oxygen-containing gas is conveyed to the upper part of the molten pool to burn with reducing gas in the flue gas, and the heat of the molten pool is supplemented.
2. The chromite smelting process according to claim 1, wherein the reducing agent is a carbon-based reducing agent; preferably, the carbon-based reducing agent is at least one of anthracite, bituminous coal, lignite, coke, graphite, semi-coke and waste carbon electrode;
Preferably, the carbon-based reducing agent is anthracite;
preferably, the weight ratio of the reducing agent to chromite is 1-5:10.
3. The chromite smelting method according to claim 1, wherein the slag former is at least one of magnesite, quartz stone, dolomite, limestone, cobble, magnesia, quartz, lime;
Preferably, slag type MgO/Al 2O3 =0.5-1.5 is controlled by a slag former in the high-temperature molten pool smelting, and the ternary alkalinity of slag is 0.5-2.
4. The chromite smelting method according to claim 1, wherein the volume fraction of oxygen in the oxygen-enriched air is 30% to 99%;
preferably, the fuel is at least one selected from pulverized coal, natural gas, coal gas, coke powder, graphite powder, heavy oil, gasoline, coal gas and hydrogen;
Preferably, the ratio of oxygen to fuel in the oxygen-enriched air is regulated in the high-temperature molten pool smelting process to ensure that the molar ratio of carbon dioxide to carbon monoxide generated by combustion is 0-1: 10.
5. The chromite smelting method according to claim 1, wherein the high temperature molten bath smelting temperature is 1500 ℃ to 1850 ℃;
preferably, the smelting temperature of the high-temperature molten pool is 1600-1780 ℃.
6. The chromite smelting process according to claim 1, wherein the oxygen-containing gas is air or oxygen-enriched air;
Preferably, the oxygen content in the oxygen-containing gas is 21% -99%.
7. The chromite smelting method according to claim 1, wherein in the high-temperature bath smelting process, the negative pressure of a hearth in the smelting equipment is-5 to-200 Pa.
8. A chromite smelting apparatus, comprising:
The smelting furnace body is used for smelting raw materials;
The first spray gun is arranged at the lower part of the smelting furnace body, and a spray gun port is immersed in slag and is used for spraying oxygen-enriched air and fuel into a molten pool for combustion;
The second spray gun is arranged at the upper part or the furnace top of the smelting furnace body and is used for conveying oxygen-containing gas to the upper part of the molten pool and burning reducing gas in the flue gas;
the flue gas discharge port is arranged at the top of the smelting furnace body and is used for discharging flue gas in the smelting furnace body;
The slag-gold discharge port is arranged on the side wall of the lower part of the smelting furnace body.
9. Chromite smelting plant according to claim 8, characterised in that it further comprises waste heat recovery means for recovering waste heat of flue gas.
10. The chromite smelting apparatus according to claim 8, further comprising a raw material inlet provided at the top of the smelting furnace body for feeding raw material into the smelting furnace body;
Preferably, the number of the first spray guns is 2-100; the number of the second spray guns is 1-20.
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