WO2022194285A1 - 铌铁矿综合利用方法 - Google Patents

铌铁矿综合利用方法 Download PDF

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WO2022194285A1
WO2022194285A1 PCT/CN2022/081742 CN2022081742W WO2022194285A1 WO 2022194285 A1 WO2022194285 A1 WO 2022194285A1 CN 2022081742 W CN2022081742 W CN 2022081742W WO 2022194285 A1 WO2022194285 A1 WO 2022194285A1
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Prior art keywords
iron
niobium
furnace
slag
comprehensive utilization
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PCT/CN2022/081742
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English (en)
French (fr)
Inventor
李东波
陈学刚
王云
郭亚光
徐小锋
黎敏
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中国恩菲工程技术有限公司
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Publication of WO2022194285A1 publication Critical patent/WO2022194285A1/zh

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    • 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
    • C22B34/00—Obtaining refractory metals
    • C22B34/20—Obtaining niobium, tantalum or vanadium
    • C22B34/24—Obtaining niobium or tantalum
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B11/00—Making pig-iron other than in blast furnaces
    • 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
    • C22B5/00—General methods of reducing to metals
    • C22B5/02—Dry methods smelting of sulfides or formation of mattes
    • C22B5/10—Dry methods smelting of sulfides or formation of mattes by solid carbonaceous reducing agents
    • 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
    • C22B59/00—Obtaining rare earth metals
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/10—Reduction of greenhouse gas [GHG] emissions
    • Y02P10/143—Reduction of greenhouse gas [GHG] emissions of methane [CH4]

Definitions

  • the invention relates to the technical field of smelting, in particular to a method for comprehensive utilization of niobium iron ore.
  • the beneficiation method requires a combination of a variety of beneficiation processes, including gravity separation, magnetic separation, flotation and other beneficiation methods.
  • the beneficiation process is long, the water consumption is large, and the equipment is large. It is especially not suitable for water-deficient areas and areas with high environmental protection requirements for water treatment.
  • the beneficiation method generally has a low element recovery rate.
  • the reduction roasting-magnetic separation process is to reduce and roast niobium iron ore in pre-reduction equipment such as rotary kiln, shaft furnace, rotary hearth furnace or fluidized bed.
  • rare earth materials this method does not realize the separation of phosphorus and iron, nor does it realize the separation of niobium and rare earth, and the extraction and separation of elements is not complete.
  • the reduction roasting-electric furnace melting and fractionation method is also to carry out reduction roasting of niobium iron ore in pre-reduction equipment such as rotary kiln, shaft furnace, rotary hearth furnace or fluidized bed, and the product can be put into the electric furnace in hot state for deep reduction, and separated out
  • pre-reduction equipment such as rotary kiln, shaft furnace, rotary hearth furnace or fluidized bed
  • the product can be put into the electric furnace in hot state for deep reduction, and separated out
  • the subsequent dephosphorization of the obtained high phosphorus ferroniobium is relatively difficult, and the niobium recovery process is long.
  • the Chinese patent application with the application publication number CN101787450A discloses a method for enriching tantalum and niobium, rare earth elements, iron and phosphorus from rare metal ores. After magnetic separation, iron and phosphorus are enriched into the magnetic material, and elements such as tantalum, niobium and rare earth are enriched in the slag. The separation of elements in this process is not complete.
  • the phosphorus content in iron-containing materials is about 10%, and the phosphorus content in iron materials is relatively high High, and many valuable elements such as tantalum, niobium and rare earth have not been effectively separated.
  • the Chinese patent application with application publication number CN105154659A discloses a method for synchronously extracting iron and niobium from Bayan Obo low-grade ore.
  • the niobium-containing minerals are pre-reduced and then melted to separate molten iron and niobium-containing slag.
  • the slag is chlorinated to obtain niobium.
  • Chloride to achieve the purpose of extracting niobium, this method uses chlorine gas with high cost, high toxicity, and difficult to handle chlorine-containing slag.
  • the Chinese patent application with the application publication number CN105907990A discloses a method for producing ferroniobium by rotary hearth furnace pre-reduction-electric furnace melting. Raw materials with low phosphorus.
  • the existing beneficiation methods have long process flow, large water consumption and more equipment, and are especially not suitable for areas with water shortage and areas with high environmental protection requirements for water treatment, and the mineral processing methods generally have a low element recovery rate.
  • reduction roasting-magnetic separation, reduction roasting-electric furnace melting, blast furnace reduction and other methods all have the problem of incomplete separation of phosphorus, iron, niobium and rare earth elements, especially phosphorus is difficult to separate out, which makes the subsequent treatment process difficult to dephosphorize , the obtained ferroniobium products are of low value.
  • the main purpose of the present invention is to provide a comprehensive utilization method of niobium iron ore, so as to solve the problems of high recovery cost of niobium iron ore and difficult separation of ferrophosphorus in the prior art.
  • a method for comprehensive utilization of niobium iron ore comprising: step S1, reducing and side blowing smelting niobium iron ore in a side blowing furnace to obtain molten iron, slag and phosphorus-containing iron ore. Flue gas; Step S2, deeply reducing the slag in the electric furnace to obtain ferroniobium, rare earth-rich slag and electric furnace flue gas.
  • step S1 includes: reducing and side blowing smelting the material including the first reducing agent and niobite in the side blowing furnace, forming a slag layer and a metal molten pool in the side blowing furnace, and the slag layer is in the metal molten pool.
  • inject fuel and oxygen-enriched gas into the side-blown furnace preferably inject fuel and oxygen-enriching gas into the slag layer, preferably the temperature of reducing side blowing smelting is 1250 ⁇ 1450°C .
  • the above-mentioned fuel is selected from any one of pulverized coal, natural gas, coal gas and heavy oil, and the oxygen content in the oxygen-enriched gas is 40-99% by volume.
  • the above-mentioned first reductant is any one or more of bituminous coal, anthracite, lignite and coke, preferably the first reductant is a block reductant or a granular reductant, preferably the combination of niobite and the first reductant.
  • the mass ratio is 100:0-50, preferably 100:20-40.
  • step S2 includes: performing deep reduction of the slag, iron-containing material, second reducing agent and flux in an electric furnace to obtain ferroniobium and rare earth-rich slag, preferably the temperature for deep reduction is 1500-1600°C.
  • the above-mentioned slag is a hot slag produced directly from the side-blown furnace
  • the iron-containing material is preferably selected from molten iron, pig iron, steel scraps, iron-containing metallized pellets, iron-containing oxidized pellets, and iron ore.
  • the second reducing agent is selected from any one or more of bituminous coal, anthracite, lignite and coke
  • the flux is selected from any one of lime, limestone and dolomite, niobite, iron-containing materials and the weight ratio of the second reducing agent and the flux is 1000:200-400:5-40:100-300.
  • At least part of the above-mentioned iron-containing material, at least part of the second reducing agent and at least part of the flux are added in the form of composite pellets, and the main components of the composite pellet include iron, carbon and calcium oxide, preferably iron, calcium oxide and carbon.
  • the weight ratio is 100:40-110:2-15, the weight content of iron in the composite pellets is 40-70%, and the weight ratio of the composite pellets and niobite is 0-400:1000.
  • the above-mentioned method for comprehensive utilization of niobium iron ore further includes: dedusting the phosphorus-containing flue gas to obtain phosphorus-containing flue gas and dedusting flue gas; optionally, purifying the dedusting flue gas after generating electricity in a waste heat boiler and evacuating it.
  • the electric furnace flue gas and the phosphorus-containing flue gas are combined for dust removal treatment.
  • the electrical energy obtained from the above-mentioned dust-removed flue gas is generated by the waste heat boiler as at least part of the electrical energy of the electric furnace in step S2.
  • niobite ore is rougher niobite obtained by gravity separation of niobite ore.
  • the reduction side blow smelting is performed on the niobium iron ore, and the phosphorus produced in the reduction process is discharged with the flue gas in time by using the side blow advantage of the reduction side blow smelting.
  • the separation of ferrophosphorus is realized, and the obtained molten iron and slag have low phosphorus content, which alleviates the problem of high phosphorus content in the raw materials in the subsequent extraction of niobium and rare earth; and based on the characteristics of side-blown smelting, the use of side-blown fuel method Heating, heating costs are low.
  • the above process does not require high-cost chlorine gas for chlorination, and the reduction side blowing smelting and deep reduction are both low-cost smelting methods, thus effectively controlling the cost of metal recovery in niobium iron ore.
  • the waste heat of the side-blown furnace can be recycled, and the generated electric energy can be used for deep reduction in the subsequent electric furnace, reducing the dependence on external electric energy resources.
  • iron-containing materials are added as an external iron source to achieve deep reduction to form niobium molten iron.
  • niobium iron ore of the present application can be directly sold or sold as corresponding products, so as to realize the separation of phosphorus, iron, niobium and rare earth elements in niobium iron ore. enrichment to achieve the purpose of comprehensive utilization of various valuable elements in niobium iron ore.
  • the present application provides a method for comprehensive utilization of niobium iron ore, which comprehensively utilizes iron niobium ore.
  • the method includes: step S1, performing reduction and side blowing smelting of niobium iron ore in a side blowing furnace to obtain molten iron, slag and phosphorus-containing flue gas; step S2, performing deep reduction on the slag in an electric furnace to obtain ferroniobium and rare earth-rich slag and furnace fumes.
  • the reduction side blowing smelting is first performed on the niobium iron ore, and the phosphorus produced in the reduction process is discharged with the flue gas in time by using the side blowing advantage of the reduction side blowing smelting, so as to realize the separation of ferrophosphorus.
  • the obtained molten iron and slag contain low phosphorus, which alleviates the problem of high phosphorus content in the raw materials in the subsequent extraction of niobium and rare earth; and based on the characteristics of side-blown smelting, the use of side-blown fuel for heating, the heating cost is relatively high. Low.
  • the above process does not require high-cost chlorine gas for chlorination, and the reduction side blowing smelting and deep reduction are both low-cost smelting methods, thus effectively controlling the cost of metal recovery in niobium iron ore.
  • the waste heat of the side-blown furnace can be recycled, and the generated electric energy can be used for deep reduction in the subsequent electric furnace, reducing the dependence on external electric energy resources.
  • iron-containing materials are added as an external iron source to achieve deep reduction to form niobium molten iron.
  • the above-mentioned side-blown reduction smelting process is in addition to the conventional carbon combustion reaction, such as:
  • Part of the reduced P enters the molten iron, and the other part is volatilized into the flue gas in the form of elemental phosphorus.
  • the phosphorus-containing flue gas, molten iron, ferroniobium, rare earth slag, etc. obtained by the comprehensive utilization method of niobium iron ore of the present application can be directly sold or sold as corresponding products, so as to realize the separation of phosphorus, iron, niobium and rare earth elements in niobium iron ore. enrichment to achieve the purpose of comprehensive utilization of various valuable elements in niobium iron ore.
  • the above-mentioned step S1 includes: performing reduction and side-blowing smelting of the material including the first reducing agent and niobite in a side-blowing furnace, forming a slag layer and a molten metal pool in the side-blowing furnace, and forming a slag layer in the side-blowing furnace.
  • the layer is above the metal molten pool, and during the reduction side blow smelting process, fuel and oxygen-enriched gas are injected into the side-blown furnace, preferably the slag layer is injected into the fuel and oxygen-enriched gas, preferably the temperature of the reduction side blow smelting It is 1250 ⁇ 1450 °C.
  • the reduction side-blown smelting is carried out by using the fuel and oxygen-enriched gas injected into the side-blowing furnace to burn to provide heat energy, which realizes full utilization of heat; on the other hand, when the fuel and oxygen-enriched gas are injected into the slag layer, the The disturbance of the slag and the volatilization of phosphorus are accelerated.
  • the fuels and reducing agents used in the above-mentioned reduction side blow smelting process of the present application can be selected with reference to the fuels and reducing agents commonly used in ore smelting side blow smelting in the prior art.
  • the oxygen volume content in the oxygen-enriched gas is 40-99%.
  • the first reducing agent is any one or more of bituminous coal, anthracite coal, lignite and coke.
  • the first reductant is a block reductant or a granular reductant, so as to avoid the first reductant being taken away by the flue gas and not being fully utilized.
  • the reduction degree and flue gas output can be controlled by adjusting the ratio of niobium iron ore to the first reducing agent. In order to achieve iron reduction as much as possible and control the subsequent flue gas treatment load, ferroniobium is preferred.
  • the mass ratio of the ore to the first reducing agent is 100:0-50, preferably 100:20-40.
  • coal or coke is both a fuel and a reducing agent, so it can also be used as a reducing agent.
  • the above step S2 includes: performing deep reduction of the slag, iron-containing material, second reducing agent and flux in an electric furnace to obtain ferroniobium and rare earth-rich slag, preferably the temperature of deep reduction is 1500 ⁇ 1600°C.
  • the low-phosphorus and low-iron slag obtained by side-blown reduction smelting is deeply reduced with iron-containing materials, the second reducing agent and flux.
  • the addition of iron-containing materials has the effect of increasing iron sources and reducing agents, reducing
  • the introduction of impurities in the deep reduction stage improves the deep reduction efficiency and reduction effect, which is conducive to reducing power consumption and improving product quality.
  • the amount of the obtained niobium-containing molten iron increases, which promotes the capture of niobium by the metal, improves the yield of niobium, and the phosphorus content in the obtained niobium iron is low.
  • the above-mentioned slag is a hot slag produced directly from a side-blown furnace.
  • the above-mentioned iron-containing materials can be selected from the iron-containing materials commonly used in the industry at present.
  • the iron-containing materials are preferably selected from molten iron, pig iron, steel scraps, iron-containing metallized pellets, iron-containing oxide pellets, iron ore. any of the .
  • the second reducing agent used in the deep reduction can be a commonly used reducing agent for the deep reduction.
  • the second reducing agent is preferably selected from any one or more of bituminous coal, anthracite, lignite and coke.
  • the flux can promote the melting of solid materials such as iron-containing materials.
  • the flux is preferably selected from any one of lime, limestone and dolomite.
  • the weight ratio of the above-mentioned niobate, iron-containing material, second reducing agent and flux is 1000:200-400:5-40:100-300 to improve the reduction efficiency of iron in the slag.
  • the main components of the composite pellets include iron, carbon and calcium oxide, preferably the weight ratio of iron, calcium oxide and carbon is 100:40-110:2-15, and the weight content of iron in the composite pellets is 40-70 %.
  • the weight ratio of the composite pellets and the niobite is 0-400:1000, so as to improve the reduction efficiency of iron in the slag.
  • the above-mentioned iron-containing material, the second reducing agent and the flux can be partially or completely added in the form of composite pellets, so the dosage of the composite pellets can be changed within the above-mentioned range of 0 to 400:1000, as long as the overall satisfaction of niobite, containing
  • the weight ratio of the iron material, the second reducing agent and the flux can be 1000:200-400:5-40:100-300.
  • the above-mentioned comprehensive utilization method of niobium iron ore further includes: performing dedusting treatment on phosphorus-containing flue gas to obtain phosphorus-containing flue gas and dedusting flue gas; null.
  • the phosphorus-containing flue gas is dedusted, and phosphorus is collected in the flue gas; then the dedusted flue gas can be passed through the waste heat boiler to generate electricity to utilize the waste heat.
  • the flue gas emitted by the waste heat boiler can be evacuated after conventional purification treatment.
  • the amount of flue gas produced by the deep reduction of the electric furnace is small.
  • the above-mentioned comprehensive utilization method of niobium iron ore is preferred to combine the flue gas of the electric furnace and the phosphorus-containing flue gas for dedusting treatment.
  • the weight percentages of the components of niobate used in the following examples are as follows, wherein the first niobate is the niobite raw ore, and the second niobate is the mineral after rough gravity separation.
  • the niobium iron ore is directly sent to the feeding port of the side-blown furnace through the belt conveyor, and put into the furnace (the amount of pre-blended coal is 0).
  • the pulverized coal and oxygen-enriched gas are injected into the molten pool by the side-blown lance.
  • the oxygen-enriched gas is composed of a mixture of oxygen and air.
  • the main technical parameters of the side-blown furnace injection system are: pulverized coal 292kg, oxygen 290Nm 3 , air 131Nm 3 , oxygen-enriched concentration 75.07%, side-blown furnace melting pool temperature is 1450 ⁇ 1500 °C, can produce 673kg of slag, phosphorus content Hot metal 106kg, soot 78kg, high temperature flue gas 784Nm 3 .
  • the slag composition 3.22% FeO, 0.47% P 2 O 5 , 0.99% Nb 2 O 5 , 1.21% REO; the phosphorus-containing molten iron composition: 0.1% C, 3.89% P, 0.03% Nb; the flue dust contains 27.99% phosphorus.
  • the slag enters the electric furnace for deep reduction and smelting.
  • 8.47kg of anthracite, 228kg of lime, and 202kg of pig iron need to be added for each ton of niobium iron ore.
  • slag composition 0.32% FeO, 0.04% Nb 2 O 5 , 0.95% REO; ferroniobium composition: 3.8% C, 0.08% P, 2.0% Nb.
  • the waste heat boiler After the high temperature flue gas of the side blowing furnace and the electric furnace is combined, the waste heat boiler is used to generate electricity.
  • the waste heat boiler generates 695KWh of electricity per ton of niobium iron ore, which is used to power the electric furnace.
  • the niobium iron ore 1 and anthracite are fed directly into the charging port of the side-blown furnace and put into the furnace according to the mass ratio of 100:10 using belt ingredients (100kg of anthracite for each ton of ore).
  • Niobium iron ore and anthracite are put into the molten pool of the side-blown furnace for reduction and side-blowing smelting.
  • Coal powder and oxygen-rich gas are injected into the molten pool by the side-blowing lance.
  • the main technical parameters of the side-blown furnace injection system are: pulverized coal 160kg, oxygen 268Nm 3 , air 37Nm 3 , oxygen-enriched concentration 89.98%, the temperature of the side-blown furnace molten pool is 1350 ⁇ 1400 °C, can produce slag 668kg, Phosphorus-containing molten iron 109kg, soot 75kg, high temperature flue gas 650Nm 3 .
  • slag composition 2.57% FeO, 0.94% P 2 O 5 , 1.00% Nb 2 O 5 , 1.22% REO; phosphorus-containing molten iron composition: 0.13% C, 3.77% P, 0.03% Nb; flue dust contains 27.57% phosphorus.
  • the slag enters the electric furnace for deep reduction and smelting.
  • 9.5kg of anthracite, 248kg of lime, and 334kg of molten iron need to be added for each ton of niobium iron ore, and the power consumption is 332KWh.
  • ferroniobium 348kg Among them, slag composition: 0.26% FeO, 0.03% Nb 2 O 5 , 0.93% REO; ferroniobium composition: 4.0% C, 0.09% P, 1.29% Nb.
  • the waste heat boiler will be used to generate electricity.
  • the second niobium iron ore and anthracite are fed into the side-blowing furnace feeding port and put into the furnace by using the belt batching (400kg of anthracite per ton of ore) according to the mass ratio of 100:40.
  • Niobium iron ore and anthracite are put into the molten pool of the side-blown furnace for reduction and side-blown smelting.
  • Natural gas and oxygen-rich gas are injected into the molten pool by the side-blown lance.
  • the main technical parameters of the side-blown furnace injection system are: natural gas 30Nm 3 , oxygen 278Nm 3 , air 722Nm 3 , oxygen-enriched concentration 42.83%, the side-blown furnace molten pool temperature is 1350 ⁇ 1400 °C, can produce slag 605kg, containing Phosphorus molten iron 172kg, soot 91kg, high temperature flue gas 1410Nm 3 .
  • the slag composition 3.22% FeO, 0.63% P 2 O 5 , 1.74% Nb 2 O 5 , 2.12% REO; the phosphorus-containing molten iron composition: 0.11% C, 2.91% P, 0.03% Nb; the flue dust contains 29.16% phosphorus.
  • the slag enters the electric furnace for deep reduction and smelting.
  • the temperature of the pool is 1550 ⁇ 1600°C
  • the output of slag is 676kg and ferroniobium is 194kg.
  • slag composition 0.32% FeO, 0.08% Nb 2 O 5 , 1.88% REO; ferroniobium composition: 4.3% C, 0.1% P, 3.55% Nb.
  • the waste heat boiler will be used to generate electricity.
  • the niobium iron ore II is directly sent to the charging port of the side-blown furnace and put into the furnace.
  • Niobium iron ore II is put into the melting pool of the side blowing furnace for reduction and side blowing smelting.
  • Coal powder, natural gas and oxygen-rich gas are injected into the melting pool by the side-blown lance.
  • the main technical parameters of the side-blown furnace injection system are: 300kg of pulverized coal, 30Nm 3 of natural gas, 304Nm 3 of oxygen, 99% oxygen concentration, the temperature of the molten pool of the side-blown furnace is 1400 ⁇ 1450°C, and the output of 594kg of slag , Phosphorus-containing molten iron 172kg, soot 91kg, high temperature flue gas 658Nm 3 .
  • the composition of slag 3.52% FeO, 0.64% P 2 O 5 , 1.77% Nb 2 O 5 , 2.16% REO; the composition of phosphorus-containing molten iron: 0.13% C, 2.9% P, 0.04% Nb; the phosphorus content of soot is 29.24%.
  • the slag enters the electric furnace for deep reduction and smelting.
  • 356kg of steel scraps, 35kg of coke, 144kg of lime are consumed per ton of niobium iron ore, and the power consumption is 378KWh.
  • ferroniobium 384kg are consumed per ton of niobium iron ore, and the power consumption is 378KWh.
  • slag composition 0.19% FeO, 0.05% Nb 2 O 5 , 1.98% REO; ferroniobium composition: 2.5% C, 0.04% P, 1.81% Nb.
  • the waste heat boiler will be used to generate electricity.
  • the niobium iron ore II is directly sent to the charging port of the side-blown furnace and put into the furnace.
  • Niobium iron ore II is put into the melting pool of the side blowing furnace for reduction and side blowing smelting.
  • Coal powder, natural gas and oxygen-rich gas are injected into the melting pool by the side-blown lance.
  • the main technical parameters of the side-blown furnace injection system are: 300kg of pulverized coal, 30Nm 3 of natural gas, 304Nm 3 of oxygen, 99% oxygen concentration, the temperature of the molten pool of the side-blown furnace is 1400 ⁇ 1450°C, and the output of 594kg of slag , Phosphorus-containing molten iron 172kg, soot 91kg, high temperature flue gas 658Nm 3 .
  • the composition of slag 3.52% FeO, 0.64% P 2 O 5 , 1.77% Nb 2 O 5 , 2.16% REO; the composition of phosphorus-containing molten iron: 0.13% C, 2.9% P, 0.04% Nb; the phosphorus content of soot is 29.24%.
  • the slag enters the electric furnace for deep reduction and smelting.
  • 398kg of steel scraps, 50kg of coke, 97kg of lime are consumed per ton of niobium iron ore, and the power consumption is 340KWh.
  • ferroniobium 436kg are consumed per ton of niobium iron ore, and the power consumption is 340KWh.
  • slag composition 0.19% FeO, 0.03% Nb 2 O 5 , 2.07% REO; ferroniobium composition: 4.5% C, 0.03% P, 1.64% Nb.
  • the waste heat boiler After the high-temperature flue gas of the side-blown furnace and the electric furnace is combined, the waste heat boiler is used to generate electricity.
  • the waste heat boiler generates 1202KWh of electricity per ton of niobium iron ore, which is used to power the electric furnace.
  • Example 5 Compared with Example 5, in the deep reduction stage of the electric furnace, when less iron source is added, that is, the mass ratio of niobium iron ore:steel scrap is 1000:100, the Nb 2 O 5 content in the slag obtained at this time is 0.17%, which is higher than The 0.03% in Example 5 shows that when iron-containing materials are appropriately added in the deep reduction stage, it is helpful for the capture of niobium.
  • Example 5 Compared with Example 5, in the deep reduction stage of the electric furnace, the deep reduction cannot be carried out without adding steel chips, and the recovery of niobium cannot be achieved without obtaining the metal phase.
  • niobium iron ore raw material is simply re-selected or directly enters the silo without beneficiation, and is used as a raw material, which simplifies or omits the beneficiation process;
  • the content of Fe and P in the slag obtained by side blowing reduction is 1-5% and 0.1-0.5% respectively.
  • the slag contains low phosphorus, and niobium and rare earth elements basically remain in the slag.
  • Coal injection reduction and volatilization smelting is carried out in the side-blown furnace, which promotes the reduction and volatilization of phosphorus in the raw materials, and realizes the volatilization and separation of phosphorus.
  • the phosphorus volatilization rate is more than 60%. >20%, soot can be used as raw material for phosphorus extraction.
  • the high-temperature flue gas of the side-blown furnace uses the waste heat boiler to recover the waste heat for power generation, and the flue gas dust removal can reach the standard discharge.
  • the recovered electric energy is used for the subsequent deep reduction of the electric furnace, and other surplus electric energy is used for the daily electricity consumption of the plant or external transmission.
  • the side-blown slag enters the electric furnace for deep reduction.
  • iron-containing materials, reducing agents and fluxes are added, or composite pellets are added to increase the quality of the metal phase and enhance the capture effect of the metal on niobium in the slag.
  • molten iron and pig iron contain carbon, which can not only supplement iron, but also have strong reducibility.
  • the addition of molten iron and pig iron can also reduce the amount of reducing agent added and reduce the heat consumption of electric furnaces.
  • the flue gas generated by the electric furnace is incorporated into the flue gas treatment system of the side-blown furnace.
  • the electric energy used is generated by the waste heat of the high-temperature flue gas of the side-blown furnace.
  • the energy flow distribution of the material inflow is reasonable, and the reduction of the side-blown furnace can be dynamically adjusted according to the reduction degree. In order to adjust the power consumption of deep reduction, it is convenient to control the reasonable distribution of energy and materials in the plant area.

Abstract

本发明提供了一种铌铁矿综合利用方法。该铌铁矿综合利用方法包括：步骤S1，将铌铁矿在侧吹炉中进行还原侧吹熔炼，得到铁水、炉渣和含磷烟气；步骤S2，对炉渣在电炉中进行深度还原，得到铌铁、富稀土渣和电炉烟气。本申请首先对铌铁矿进行还原侧吹熔炼实现了磷铁的分离，所得铁水和炉渣中含磷较低，减轻了后续提取铌和稀土过程中原料中磷含量高带来的问题，且还原侧吹熔炼和深度还原均为低成本熔炼方式，因此有效控制了铌铁矿中金属回收的成本。同时，侧吹炉余热可回收利用，产出的电能可用于后续电炉中的深度还原，减少对外部电能资源的依赖。深度还原阶段，添加含铁物料作为外加铁源实现深度还原，形成铌铁水。

Description

铌铁矿综合利用方法 技术领域
本发明涉及冶炼技术领域，具体而言，涉及一种铌铁矿综合利用方法。
背景技术
目前铌、铁、磷及稀土等多种元素伴生的矿物一般采用选矿、还原焙烧-磁选、还原焙烧-电炉熔分、高炉还原等的方式对有价元素进行分离和富集。
通常选矿方法需多种选矿工艺联合，包括重选、磁选、浮选等选矿方法，选矿流程长、用水量大、设备较多，尤其不适合缺水区域和水处理环保要求高的区域，且选矿方法一般元素回收率较低。还原焙烧-磁选工艺是将铌铁矿在回转窑、竖炉、转底炉或流化床等预还原设备中进行还原焙烧，产物经破碎后磁选分离出含铁、磷物料和含铌、稀土物料，该方法并没有实现磷和铁的分离，也没有实现铌和稀土的分离，元素提取分离不彻底。还原焙烧-电炉熔分方式也是将铌铁矿在回转窑、竖炉、转底炉或流化床等预还原设备中进行还原焙烧，产物可热态投入至电炉中进行深度还原，分离出含磷、铌、铁的高磷铌铁和富稀土炉渣，所得的高磷铌铁后续脱磷难度较大，铌回收工序较长。高炉还原铌铁矿工艺是将铌铁矿烧结造块，并在高炉内进行还原，所得产品也为高磷铌铁和富稀土炉渣，同样存在铌铁后续脱磷难度大、铌回收工序较长的问题。
申请公布号为CN101787450A的中国专利申请公开了一种从稀有金属矿石中富集钽铌、稀土元素、铁和磷的方法，将矿物、熔剂和还原剂按比例混合压球后焙烧，焙烧产物再经磁选将铁、磷富集到磁性物质中，钽、铌及稀土等元素富集在渣中，该工艺元素分离不彻底，含铁物质中磷含量约10％，铁物料中含磷较高，且钽、铌及稀土等多种有价元素仍未能有效分离出。
申请公布号为CN105154659A的中国专利申请公开了一种白云鄂博低品位矿同步提取铁和铌的方法，含铌矿物预还原后熔融，分离出铁水和含铌渣，炉渣在经氯化得到铌的氯化物，实现提取铌的目的，本方法使用氯气成本较高、毒性大、含氯炉渣也难以处理。
申请公布号为CN105907990A的中国专利申请公开了一种转底炉预还原-电炉熔分的生产铌铁的方法，但该方法不具有脱磷作用，所得铌铁磷含量较高，仅能处理含磷较低的原料。
可见，现有选矿方式工艺流程长、用水量大、设备较多，尤其不适合缺水区域和水处理环保要求高的区域，且选矿方法一般元素回收率较低。而还原焙烧-磁选、还原焙烧-电炉熔分、高炉还原等方式均存在磷、铁、铌及稀土等元素分离不彻底的问题，尤其是磷难以分离出去，导致后续处理工序脱磷难度大，所得铌铁产品价值不高。还原焙烧-磁选、还原焙烧-电炉熔分、高炉还原等工艺还存在预处理流程长，需要造球或烧结工序，且高炉还原的方法还存在大量 消耗焦炭的问题。还原焙烧-电炉熔分工艺需要额外消耗电能，能耗成本高，尤其对于缺电或用电成本较高区域更不适合。
发明内容
本发明的主要目的在于提供一种铌铁矿综合利用方法，以解决现有技术中的铌铁矿回收成本高、磷铁难分离的问题。
为了实现上述目的，根据本发明的一个方面，提供了一种铌铁矿综合利用方法，包括：步骤S1，将铌铁矿在侧吹炉中进行还原侧吹熔炼，得到铁水、炉渣和含磷烟气；步骤S2，对炉渣在电炉中进行深度还原，得到铌铁、富稀土渣和电炉烟气。
进一步地，上述步骤S1包括：将包括第一还原剂和铌铁矿的物料在侧吹炉中进行还原侧吹熔炼，在侧吹炉中形成炉渣层和金属熔池，炉渣层在金属熔池的上方，且在还原侧吹熔炼的过程中向侧吹炉中喷入燃料和富氧气体，优选向炉渣层中喷入燃料和富氧气体，优选还原侧吹熔炼的温度为1250～1450℃。
进一步地，上述燃料选自煤粉、天然气、煤气和重油中的任意一种，富氧气体中氧气体积含量40～99％。
进一步地，上述第一还原剂为烟煤、无烟煤、褐煤和焦炭中的任意一种或多种，优选第一还原剂为块状还原剂或粒状还原剂，优选铌铁矿与第一还原剂的质量比为100∶0～50，优选为100∶20～40。
进一步地，上述步骤S2包括：将炉渣、含铁物料、第二还原剂和熔剂在电炉中进行深度还原，得到铌铁和富稀土渣，优选深度还原的温度为1500～1600℃。
进一步地，上述炉渣为直接从侧吹炉中产出的热态炉渣，优选含铁物料选自铁水、生铁、钢屑、含铁金属化球团、含铁氧化球团、铁矿石中的任意一种，优选第二还原剂选自烟煤、无烟煤、褐煤和焦炭中的任意一种或多种，优选熔剂选自石灰、石灰石和白云石中的任意一种，铌铁矿、含铁物料、第二还原剂和熔剂的重量比为1000∶200～400∶5～40∶100～300。
进一步地，至少部分上述含铁物料、至少部分第二还原剂和至少部分熔剂以复合球团的方式加入，复合球团的主要成分包括铁、碳和氧化钙，优选铁、氧化钙和碳的重量比为100∶40～110∶2～15，复合球团中铁的重量含量为40～70％，复合球团和铌铁矿的重量比为0～400∶1000。
进一步地，上述铌铁矿综合利用方法还包括：对含磷烟气进行除尘处理，得到含磷烟尘和除尘烟气；可选地，将除尘烟气经余热锅炉发电后净化处理排空。
进一步地，上述铌铁矿综合利用方法将电炉烟气和含磷烟气合并后进行除尘处理。
进一步地，上述除尘烟气经余热锅炉发电所得电能作为步骤S2的电炉的至少部分电能。
进一步地，上述铌铁矿为铌铁矿矿石经过重选得到的粗选铌铁矿。
应用本发明的技术方案，本申请的铌铁矿综合利用方法中，首先对铌铁矿进行还原侧吹熔炼，利用还原侧吹熔炼的侧吹优势将还原过程中产生的磷及时随烟气排出，实现了磷铁的分离，所得铁水和炉渣中含磷较低，减轻了后续提取铌和稀土过程中原料中磷含量高带来的问题；而且基于侧吹熔炼的特点，使用侧吹燃料方式供热，供热成本较低。另外，上述过程不需要成本较高的氯气进行氯化，还原侧吹熔炼和深度还原均为低成本熔炼方式，因此有效控制了铌铁矿中金属回收的成本。同时，侧吹炉余热可回收利用，产出的电能可用于后续电炉中的深度还原，减少对外部电能资源的依赖。深度还原阶段，添加含铁物料作为外加铁源实现深度还原，形成铌铁水。本申请的铌铁矿综合利用方法所得的含磷烟气、铁水、铌铁、稀土炉渣等可直接出售或制成相应产品出售，实现铌铁矿中磷、铁、铌及稀土等元素的分离富集，达到铌铁矿中多种有价元素综合利用的目的。
具体实施方式
需要说明的是，在不冲突的情况下，本申请中的实施例及实施例中的特征可以相互组合。下面将并结合实施例来详细说明本发明。
如本申请背景技术所分析的，现有技术中的铌铁矿回收成本高、磷铁难分离，为了解决该问题，本申请提供了一种铌铁矿综合利用方法，该铌铁矿综合利用方法包括：步骤S1，将铌铁矿在侧吹炉中进行还原侧吹熔炼，得到铁水、炉渣和含磷烟气；步骤S2，对炉渣在电炉中进行深度还原，得到铌铁、富稀土渣和电炉烟气。
本申请的铌铁矿综合利用方法中，首先对铌铁矿进行还原侧吹熔炼，利用还原侧吹熔炼的侧吹优势将还原过程中产生的磷及时随烟气排出，实现了磷铁的分离，所得铁水和炉渣中含磷较低，减轻了后续提取铌和稀土过程中原料中磷含量高带来的问题；而且基于侧吹熔炼的特点，使用侧吹燃料方式供热，供热成本较低。另外，上述过程不需要成本较高的氯气进行氯化，还原侧吹熔炼和深度还原均为低成本熔炼方式，因此有效控制了铌铁矿中金属回收的成本。同时，侧吹炉余热可回收利用，产出的电能可用于后续电炉中的深度还原，减少对外部电能资源的依赖。深度还原阶段，添加含铁物料作为外加铁源实现深度还原，形成铌铁水。
具体地，上述侧吹还原熔炼过程除了常规的碳燃烧反应，比如：
C+O 2↑＝CO↑、2C+O 2↑＝2CO↑、CH 4↑+3O 2↑＝CO 2↑+2H 2O↑，
还发生如下铁的还原：
C+Fe 2O 3＝2FeO+CO↑、CO↑+Fe 2O 3＝2FeO+CO 2↑、C+FeO＝Fe+CO↑；
以及P的还原挥发反应，比如：
5C+P 2O 5＝2P↑+5CO↑、5C+2P 2O 5＝4P↑+5CO 2↑，
被还原的P部分进入铁水，另一部分则以磷单质的形式挥发进入烟气中。
在电炉中进行的深度还原阶段，炉渣中Nb 2O 5开始被还原，并与加入的铁源和碳一起形成铌铁水，Nb 2O 5+5C＝2Nb+5CO↑，此阶段由于还原性较强，不产生CO 2。
本申请的铌铁矿综合利用方法所得的含磷烟气、铁水、铌铁、稀土炉渣等可直接出售或制成相应产品出售，实现铌铁矿中磷、铁、铌及稀土等元素的分离富集，达到铌铁矿中多种有价元素综合利用的目的。
本申请上述步骤S1所处理的铌铁矿可以为铌铁矿矿石或者为铌铁矿矿石经过重选得到的粗选铌铁矿。即使经过重选，由于重选流程去除矿石中的大部分石英即有价元素含量低的硅酸盐成分，该流程相对于现有技术中的选矿流程简单、流程少、用水少，避免了多种有价金属的损失。且采用本申请的方法，铌铁矿可以直接在侧吹炉中进行处理，不需要进行干造球、预还原等原料预处理工序，减少了冶炼配套设施。
在本申请一些实施例中，上述步骤S1包括：将包括第一还原剂和铌铁矿的物料在侧吹炉中进行还原侧吹熔炼，在侧吹炉中形成炉渣层和金属熔池，炉渣层在金属熔池的上方，且在还原侧吹熔炼的过程中向侧吹炉中喷入燃料和富氧气体，优选向炉渣层中喷入燃料和富氧气体，优选还原侧吹熔炼的温度为1250～1450℃。利用向侧吹炉内喷入的燃料和富氧气体燃烧提供热能进行还原侧吹熔炼，实现了对热量的充分利用；另一方面，在向炉渣层中喷入燃料和富氧气体时，实现了炉渣的扰动，加快了磷的挥发。
本申请上述还原侧吹熔炼过程所采用的燃料和还原剂均可以现有技术中矿石冶炼侧吹熔炼常用的燃料和还原剂为参考进行选择，为了提高热能利用并且减少杂质引入，优选上述燃料选自煤粉、天然气、煤气和重油中的任意一种，富氧气体中氧气体积含量40～99％。
优选地，上述第一还原剂为烟煤、无烟煤、褐煤和焦炭中的任意一种或多种。优选第一还原剂为块状还原剂或粒状还原剂，避免了第一还原剂被烟气带走而不能充分利用。在侧吹还原熔炼过程中，可以通过调整铌铁矿和第一还原剂的比例来调控还原程度和烟气产量，为了尽可能实现铁的还原，并控制后续的烟气处理负荷，优选铌铁矿与第一还原剂的质量比为100∶0～50，优选为100∶20～40。
还原侧吹熔炼阶段，煤或焦既是燃料也具有还原性，因此还可以作为还原剂使用，其加入方式有两种，与铌铁矿一起预配入(比如通过皮带预配入)，或通过侧吹喷枪喷吹进入熔池中，因此当采用煤粉作为燃料时，其既可以作为燃料提供热量又可以作为还原剂用于还原铁。
在本申请另一些实施例中，上述步骤S2包括：将炉渣、含铁物料、第二还原剂和熔剂在电炉中进行深度还原，得到铌铁和富稀土渣，优选深度还原的温度为1500～1600℃。
侧吹还原熔炼所得到的低磷、低铁炉渣与含铁物料、第二还原剂和熔剂进行深度还原，在该深度还原阶段，含铁物料的加入具有增加铁源和还原剂的作用，减少了深度还原阶段杂 质的引入，提高深度还原效率和还原效果，利于降低电耗和提升产品质量。所得含铌铁水量增加，促进了金属对铌的捕集，提高了铌的收率，且所得铌铁中磷含量较低。
为了提高能源利用效率，优选上述炉渣为直接从侧吹炉中产出的热态炉渣。
上述含铁物料可以选用目前工业常用的含铁材料，为了降低成本和便于利用，优选含铁物料选自铁水、生铁、钢屑、含铁金属化球团、含铁氧化球团、铁矿石中的任意一种。深度还原所用的第二还原剂可以采用深度还原常用的还原剂，为了降低成本，优选第二还原剂选自烟煤、无烟煤、褐煤和焦炭中的任意一种或多种。熔剂可以促进含铁物料等固态材料的熔融，为了降低成本，优选熔剂选自石灰、石灰石和白云石中的任意一种。
经过试验探索，优选上述铌铁矿、含铁物料、第二还原剂和熔剂的重量比为1000∶200～400∶5～40∶100～300，以提高炉渣中铁的还原效率。
在一些实施例中，至少部分上述含铁物料、至少部分第二还原剂和至少部分熔剂以复合球团的方式加入，简化了物料加入方式，提高了各主要元素配比的精确性。优选地，上述复合球团的主要成分包括铁、碳和氧化钙，优选铁、氧化钙和碳的重量比为100∶40～110∶2～15，复合球团中铁的重量含量为40～70％。复合球团和铌铁矿的重量比为0～400∶1000，以提高炉渣中铁的还原效率。上述含铁物料、第二还原剂和熔剂可以部分或全部以复合球团的方式加入，因此复合球团的用量可以在上述0～400∶1000的范围内变化，只要整体满足铌铁矿、含铁物料、第二还原剂和熔剂的重量比为1000∶200～400∶5～40∶100～300即可。
在一些实施例中，上述铌铁矿综合利用方法还包括：对含磷烟气进行除尘处理，得到含磷烟尘和除尘烟气；可选地，将除尘烟气经余热锅炉发电后净化处理排空。对含磷烟气进行除尘处理，将磷收集在烟尘中；接着可以将除尘烟气经余热锅炉进行发电以利用其中的余热。余热锅炉放出的烟气经过常规的净化处理即可排空。经过上述过程，对还原侧吹熔炼的烟气热量和资源进行有效的回收利用，提高了本申请方法的综合效益。
电炉深度还原所产生的烟气量较少，为了减少设备投资，优选上述铌铁矿综合利用方法将电炉烟气和含磷烟气合并后进行除尘处理。
进一步地，为了实现能源综合利用，优选上述除尘烟气经余热锅炉发电所得电能作为步骤S2的电炉的至少部分电能。在实施本申请的方法时，可以通过调整还原侧吹熔炼的还原程度和深度还原阶段所配物料类型，灵活调整烟气余热发电量和深度还原段电能消耗，可以实现厂区内电能产销平衡，不依赖外界电能，也不使电能过剩，可独立建厂不依赖外界社会基础建设条件，特别适合电力系统基础设施不发达区域，该工艺建厂条件要求低，选址灵活。
以下将结合实施例和对比例，进一步说明本申请的有益效果。
以下实施例使用的铌铁矿成分重量百分含量如下，其中铌铁矿一为铌铁矿原矿，铌铁矿二为粗重选之后矿物。
表1
矿物种类 Fe 2O 3 FeO K 2O P 2O 5 CaO MgO SiO 2 Al 2O 3 Nb 2O 5 REO 水分 未知
铌铁矿一 16.67 031 2.54 6.28 7.57 0.37 37.39 10.39 0.69 0.84 13.52 余量
铌铁矿二 25.68 0.48 3.71 7.64 9.82 0.48 24.26 10.95 108 132 10.92 余量
实施例1
将铌铁矿一通过皮带机直接送入至侧吹炉加料口，投入炉内(预配煤量为0)。
铌铁矿一投入至侧吹炉熔池内进行还原侧吹熔炼，煤粉和富氧气体由侧吹喷枪喷入熔池中富含氧气体由氧气和空气混合组成，处理每吨铌铁矿时，侧吹炉喷吹系统主要技术参数为：煤粉292kg，氧气290Nm 3，空气131Nm 3，富氧浓度75.07％，侧吹炉熔池温度为1450～1500℃，可产出炉渣673kg、含磷铁水106kg、烟尘78kg、高温烟气784Nm 3。其中，炉渣成分：3.22％FeO、0.47％P 2O 5、0.99％Nb 2O 5、1.21％REO；含磷铁水成分：0.1％C、3.89％P、0.03％Nb；烟尘含磷27.99％。
炉渣进入电炉内进行深度还原熔炼，电炉深度还原阶段处理每吨铌铁矿所需加入无烟煤8.47kg，石灰228kg，生铁块202kg，耗电339KWh，电炉熔池温度1500～1550℃，可产出炉渣861kg，铌铁220kg。其中，炉渣成分：0.32％FeO、0.04％Nb 2O 5、0.95％REO；铌铁成分：3.8％C、0.08％P、2.0％Nb。
侧吹炉和电炉高温烟气汇合后使用余热锅炉发电，处理每吨铌铁矿余热锅炉发电量为695KWh，为电炉供电。
实施例2
将铌铁矿一、无烟煤按照质量比为100∶10的配比使用皮带配料(每吨矿配加无烟煤100kg)，直接送入至侧吹炉加料口，投入炉内。
铌铁矿一和无烟煤投入至侧吹炉熔池内进行还原侧吹熔炼，煤粉和富氧气体由侧吹喷枪喷入熔池中富含氧气体由氧气和空气混合组成，处理每吨铌铁矿时，侧吹炉喷吹系统主要技术参数为：煤粉160kg，氧气268Nm 3，空气37Nm 3，富氧浓度89.98％，侧吹炉熔池温度为1350～1400℃，可产出炉渣668kg、含磷铁水109kg、烟尘75kg、高温烟气650Nm 3。其中，炉渣成分：2.57％FeO、0.94％P 2O 5、1.00％Nb 2O 5、1.22％REO；含磷铁水成分：0.13％C、3.77％P、0.03％Nb；烟尘含磷27.57％。
炉渣进入电炉内进行深度还原熔炼，电炉深度还原阶段处理每吨铌铁矿所需加入无烟煤9.5kg，石灰248kg，铁水334kg，耗电332KWh，电炉熔池温度1500～1550℃，可产出炉渣877kg，铌铁348kg。其中，炉渣成分：0.26％FeO、0.03％Nb 2O 5、0.93％REO；铌铁成分：4.0％C、0.09％P、1.29％Nb。
侧吹炉和电炉高温烟气汇合后使用余热锅炉发电，处理每吨铌铁矿余热锅炉发电量为590KWh，为电炉供电。
实施例3
将铌铁矿二、无烟煤按照质量比为100∶40的配比使用皮带配料(每吨矿配加无烟煤400kg)，直接送入至侧吹炉加料口，投入炉内。
铌铁矿二和无烟煤投入至侧吹炉熔池内进行还原侧吹熔炼，天然气和富氧气体由侧吹喷枪喷入熔池中富含氧气体由氧气和空气混合组成，处理每吨铌铁矿时，侧吹炉喷吹系统主要技术参数为：天然气30Nm 3，氧气278Nm 3，空气722Nm 3，富氧浓度42.83％，侧吹炉熔池温度为1350～1400℃，可产出炉渣605kg、含磷铁水172kg、烟尘91kg、高温烟气1410Nm 3。其中，炉渣成分：3.22％FeO、0.63％P 2O 5、1.74％Nb 2O 5、2.12％REO；含磷铁水成分：0.11％C、2.91％P、0.03％Nb；烟尘含磷29.16％。
炉渣进入电炉内，进行深度还原熔炼，电炉深度还原阶段处理每吨铌铁矿所需加入复合球团388kg(球团中Fe∶CaO∶C＝100∶57∶15)，耗电371KWh，电炉熔池温度1550～1600℃，可产出炉渣676kg，铌铁194kg。其中，炉渣成分：0.32％FeO、0.08％Nb 2O 5、1.88％REO；铌铁成分：4.3％C、0.1％P、3.55％Nb。
侧吹炉和电炉高温烟气汇合后使用余热锅炉发电，处理每吨铌铁矿余热锅炉发电量为1183KWh，为电炉供电。
实施例4
将铌铁矿二直接送入至侧吹炉加料口，投入炉内。
铌铁矿二投入至侧吹炉熔池内进行还原侧吹熔炼，煤粉、天然气和富氧气体由侧吹喷枪喷入熔池中富含氧气体由氧气和空气混合组成，处理每吨铌铁矿时，侧吹炉喷吹系统主要技术参数为：喷吹煤粉300kg，天然气30Nm 3，氧气304Nm 3，氧气浓度99％，侧吹炉熔池温度为1400～1450℃，可产出炉渣594kg，含磷铁水172kg，烟尘91kg，高温烟气658Nm 3。其中，炉渣成分：3.52％FeO、0.64％P 2O 5、1.77％Nb 2O 5、2.16％REO；含磷铁水成分：0.13％C、2.9％P、0.04％Nb；烟尘含磷29.24％。
炉渣进入电炉内，进行深度还原熔炼，电炉深度还原阶段处理每吨铌铁矿需消耗钢屑356kg，焦炭35kg，石灰144kg，耗电378KWh，电炉熔池温度1550～1600℃，可产出炉渣646kg，铌铁384kg。其中，炉渣成分：0.19％FeO、0.05％Nb 2O 5、1.98％REO；铌铁成分：2.5％C、0.04％P、1.81％Nb。
侧吹炉和电炉高温烟气汇合后使用余热锅炉发电，处理每吨铌铁矿余热锅炉发电量为1532KWh，为电炉供电。
实施例5
将铌铁矿二直接送入至侧吹炉加料口，投入炉内。
铌铁矿二投入至侧吹炉熔池内进行还原侧吹熔炼，煤粉、天然气和富氧气体由侧吹喷枪喷入熔池中富含氧气体由氧气和空气混合组成，处理每吨铌铁矿时，侧吹炉喷吹系统主要技术参数为：喷吹煤粉300kg，天然气30Nm 3，氧气304Nm 3，氧气浓度99％，侧吹炉熔池温度为1400～1450℃，可产出炉渣594kg，含磷铁水172kg，烟尘91kg，高温烟气658Nm 3。其中，炉渣成分：3.52％FeO、0.64％P 2O 5、1.77％Nb 2O 5、2.16％REO；含磷铁水成分：0.13％C、2.9％P、0.04％Nb；烟尘含磷29.24％。
炉渣进入电炉内，进行深度还原熔炼，电炉深度还原阶段处理每吨铌铁矿需消耗钢屑398kg，焦炭50kg，石灰97kg，耗电340KWh，电炉熔池温度1550～1600℃，可产出炉渣618kg，铌铁436kg。其中，炉渣成分：0.19％FeO、0.03％Nb 2O 5、2.07％REO；铌铁成分：4.5％C、0.03％P、1.64％Nb。
侧吹炉和电炉高温烟气汇合后使用余热锅炉发电，处理每吨铌铁矿余热锅炉发电量为1202KWh，为电炉供电。
实施例6
同实施例5对比，在电炉深度还原阶段，添加较少铁源时，即铌铁矿：钢屑质量比为1000∶100，此时获得的炉渣中Nb 2O 5含量为0.17％，高于实施例5中的0.03％，说明深度还原阶段适当增加含铁物料时，有助于铌的捕集。
对比例1
同实施例5对比，在电炉深度还原阶段，不添加钢屑无法进行深度还原，无法获得金属相无法实现铌的回收。
从以上的描述中，可以看出，本发明上述的实施例实现了如下技术效果：
1)铌铁矿原料进行简单重选或不进行选矿直接进入料仓，作为原料使用，简化或省略了选矿工序；
2)铌铁矿与还原剂皮带机配料后，直接投入至侧吹炉，炉内快速实现升温、熔化和还原等多个过程，省去了原料预处理过程，处理流程较短；
3)侧吹还原所得铁水中P、Nb含量分别＜4％，＜0.05％，铁水磷、铌含量较低，实现了铁的分离。
4)侧吹还原所得炉渣中Fe、P含量分别为1～5％，0.1～0.5％，渣含磷较低，铌和稀土元素基本仍残留在炉渣中。
5)侧吹炉内进行喷煤还原挥发冶炼，促进了原料中磷的还原挥发，实现磷的挥发分离，磷挥发率＞60％，大部分磷进入烟尘，可获得含磷烟尘，烟尘磷含量＞20％，烟尘可作为提磷原料。
6)侧吹炉高温烟气使用余热锅炉回收余热发电，烟气除尘可达标排放，所回收电能用于后续电炉深度还原，其他富余电能用于厂区日常用电或对外输送。
7)侧吹炉渣进入电炉内进行深度还原，深度还原阶段加入含铁物料、还原剂和熔剂，或加入复合球团，增加金属相质量，可增强金属对渣中铌的捕集效果。比如铁水、生铁块中含有碳，不仅可以补充铁，还具有较强还原性，铁水和生铁的加入还具有减少还原剂加入量、降低电炉热量消耗的作用。
8)电炉深度还原所得铌铁水中C、Nb、P含量分别为2.0～4.5％、0.5～4％、＜0.1％，含磷较低，后续脱磷成本较低。
9)电炉深度还原所得富稀土渣中Fe、Nb、RE含量分别为＜0.5％、＜0.1％、＞0.5％，铌的提取较彻底，稀土富集效果好，增强了铌和稀土的分离效果。
10)电炉所产生的烟气并入侧吹炉烟气处理系统，所用电能来自侧吹炉高温烟气的余热发电，物质流入能量流分布合理，且可依据还原程度动态调整侧吹炉的还原度，进而调整深度还原电能消耗，便于控制厂区能量与物质的合理分布。
以上所述仅为本发明的优选实施例而已，并不用于限制本发明，对于本领域的技术人员来说，本发明可以有各种更改和变化。凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (11)

  1. 一种铌铁矿综合利用方法，其特征在于，包括：
    步骤S1，将铌铁矿在侧吹炉中进行还原侧吹熔炼，得到铁水、炉渣和含磷烟气；
    步骤S2，对所述炉渣在电炉中进行深度还原，得到铌铁、富稀土渣和电炉烟气。
  2. 根据权利要求1所述的铌铁矿综合利用方法，其特征在于，所述步骤S1包括：
    将包括第一还原剂和所述铌铁矿的物料在侧吹炉中进行还原侧吹熔炼，在所述侧吹炉中形成炉渣层和金属熔池，所述炉渣层在所述金属熔池的上方，且在所述还原侧吹熔炼的过程中向所述侧吹炉中喷入燃料和富氧气体，优选向所述炉渣层中喷入所述燃料和所述富氧气体，优选所述还原侧吹熔炼的温度为1250～1450℃。
  3. 根据权利要求2所述的铌铁矿综合利用方法，其特征在于，所述燃料选自煤粉、天然气、煤气和重油中的任意一种，所述富氧气体中氧气体积含量40～99％。
  4. 根据权利要求2所述的铌铁矿综合利用方法，其特征在于，所述第一还原剂为烟煤、无烟煤、褐煤和焦炭中的任意一种或多种，优选所述第一还原剂为块状还原剂或粒状还原剂，优选所述铌铁矿与所述第一还原剂的质量比为100∶0～50，优选为100∶20～40。
  5. 根据权利要求1所述的铌铁矿综合利用方法，其特征在于，所述步骤S2包括：
    将所述炉渣、含铁物料、第二还原剂和熔剂在所述电炉中进行深度还原，得到铌铁和富稀土渣，优选所述深度还原的温度为1500～1600℃。
  6. 根据权利要求5所述的铌铁矿综合利用方法，其特征在于，所述炉渣为直接从所述侧吹炉中产出的热态炉渣，优选所述含铁物料选自铁水、生铁、钢屑、含铁金属化球团、含铁氧化球团、铁矿石中的任意一种，优选所述第二还原剂选自烟煤、无烟煤、褐煤和焦炭中的任意一种或多种，优选所述熔剂选自石灰、石灰石和白云石中的任意一种，所述铌铁矿、所述含铁物料、所述第二还原剂和所述熔剂的重量比为1000∶200～400∶5～40∶100～300。
  7. 根据权利要求5或6所述的铌铁矿综合利用方法，其特征在于，至少部分所述含铁物料、至少部分所述第二还原剂和至少部分所述熔剂以复合球团的方式加入，所述复合球团的主要成分包括铁、碳和氧化钙，优选所述铁、所述氧化钙和所述碳的重量比为100∶40～110∶2～15，所述复合球团中所述铁的重量含量为40～70％，所述复合球团和所述铌铁矿的重量比为0～400∶1000。
  8. 根据权利要求1所述的铌铁矿综合利用方法，其特征在于，所述铌铁矿综合利用方法还包括：
    对所述含磷烟气进行除尘处理，得到含磷烟尘和除尘烟气；
    可选地，将所述除尘烟气经余热锅炉发电后净化处理排空。
  9. 根据权利要求8所述的铌铁矿综合利用方法，其特征在于，所述铌铁矿综合利用方法将所述电炉烟气和所述含磷烟气合并后进行所述除尘处理。
  10. 根据权利要求8所述的铌铁矿综合利用方法，其特征在于，所述除尘烟气经所述余热锅炉发电所得电能作为所述步骤S2的电炉的至少部分电能。
  11. 根据权利要求1所述的铌铁矿综合利用方法，其特征在于，所述铌铁矿为铌铁矿矿石经过重选得到的粗选铌铁矿。
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