CN102168156A - Iron and aluminum melting separation method for complicated and hard-dressing aluminum and iron intergrowth ore - Google Patents

Abstract

The invention provides a method for melting and separating iron and aluminum of aluminum-iron paragenetic ore with complex embedding and refractory separation. The method comprises: loading the aluminum-iron paragenetic ore into the pre-reduction furnace (1), then feeding carbon monoxide and/or hydrogen into the pre-reduction furnace (1) to partially reduce the aluminum-iron paragenetic ore, and then partially reducing the The aluminum-iron paragenetic ore is put into the final reduction melting furnace (2), and the final reduction is further carried out by carbon heat and high temperature, and the upper and lower liquid phases are formed by using the different specific gravity of molten iron and alumina-containing slag at high temperature. Tapping and slag discharge to complete melt separation. The invention can realize the complete separation of iron and aluminum in the refractory complex aluminum-iron symbiotic ore, simultaneously ensure the high recovery rate of iron and aluminum and realize the comprehensive utilization of the complex refractory aluminum-iron symbiotic ore. Moreover, the process of the invention can obtain products such as iron, alumina, high-quality gas, cement and carbon dioxide without exhaust gas and waste residue, and has the characteristics of low energy consumption and high recovery rate.

Description

A method for melting and separating iron and aluminum of complex refractory aluminum-iron paragenetic ore

technical field

The invention belongs to the technical field of metallurgy, and relates to a smelting process for smelting aluminum-iron paragenetic ore based on a coal-oxygen smelting reduction method to separate high-temperature molten slag and iron.

Background technique

my country is rich in iron ore resources, and its total reserves rank among the top in the world, but it also shows the following characteristics: (1) The ore grade is low, and most of the iron ore resources are lean ores with relatively little iron content; (2) Polymetallic The symbiotic ore occupies a certain proportion, and the symbiotic elements with recycling value are often associated with iron-based ores, such as vanadium-titanium magnetite, rare earth symbiotic ore, aluminum-iron symbiotic iron ore, etc.; (3) each valuable element in the ore Difficult to sort, especially polymetallic symbiotic ore, it is difficult to find an effective way to achieve effective separation and extraction of each element. Among them, in my country's Guangxi, Guangdong, Anhui and adjacent Southeast Asian countries such as India and Indonesia, there are a large number of complex and difficult-to-handle aluminum-iron symbiotic ores, which are important iron ore and bauxite resources. This is because as the resources of high-grade and easy-to-separate iron ore are decreasing day by day, the resources are gradually becoming depleted, and the prices of iron ore and bauxite continue to rise year after year. It is urgent to rely on technological progress to maximize the development and utilization of these low Aluminum-iron paragenetic ore resources with complex grades and difficult selection are used to alleviate the shortage of iron and aluminum resources at home and abroad and the pressure of sharply rising prices of iron ore and bauxite, and to make corresponding contributions to the comprehensive utilization of natural resources in my country. Therefore, this The invention has important practical significance.

Aluminum in aluminum-iron symbiotic ores mainly exists in iron minerals in the form of fine particles or in the form of isomorphism. It is precisely the dense distribution of aluminum-iron minerals that makes it impossible to effectively realize aluminum by beneficiation. The dissociation of iron monomers has made aluminum-iron composite ore a typical refractory ore, which has not been well developed and utilized. How to utilize a large amount of aluminum-iron symbiotic ore resources accumulated at home and abroad to develop efficient aluminum-iron separation technology and realize the comprehensive utilization of aluminum-iron symbiotic ore resources is one of the important technical and process challenges for ferrous metal smelting and non-ferrous metal extraction. one. The grade of iron in Al-Fe paragenetic ore is relatively low, generally containing Fe ₂ O ₃ in the range of 35-48%, which has no economic extraction value from the perspective of iron and steel metallurgy; Economically valuable elements such as aluminum, titanium, vanadium, gallium, etc., generally contain Al ₂ O ₃ in the range of 20-40%. From the perspective of non-ferrous metallurgy, when aluminum metal is extracted efficiently, it is necessary to complete clinker roasting and aluminum-iron How to combine the extraction of iron and aluminum to construct a technically and economically feasible process will be the key issue for the comprehensive utilization of aluminum-iron symbiotic ores.

At present, domestic and foreign studies on the separation methods of aluminum and iron in aluminum-iron symbiotic ores are mainly divided into three ways:

(1) Sorting first, followed by smelting, that is, the ore is separated into high-grade aluminum concentrate and iron concentrate by mineral processing, and then aluminum and iron are extracted from the respective concentrates by adopting their respective processes. This approach includes the application of hydrocyclone classification, dispersion-flocculation, shaking table, gravity separation of jigging, magnetic separation, magnetic separation-flotation combined process, chemical roasting-leaching process, etc., this method It is suitable for processing aluminum-containing iron ore with simple structure. It has no obvious effect on ores with complex aluminum-iron intercalation relationship and poor dissociation performance. The problem lies in the physical beneficiation process including gravity separation, magnetic separation and flotation. , or use the chemical beneficiation process of adding chemical reagents to extract iron to reduce aluminum, because the particle size of aluminum and iron in this type of ore is very fine, and the relationship between aluminum and iron in the ore is complicated. On the one hand, this method causes iron. The recovery rate is difficult to guarantee. On the other hand, the content of Al ₂ O ₃ in the iron concentrate is still high, which is difficult to meet the production requirements of the iron-making industry;

(2) Aluminum first and then iron, that is, the Bayer process of dissolving aluminum/red mud to recover iron. This process has some research results for the recovery of iron in red mud. These results have reference and guiding significance for the separation of iron and aluminum in aluminum-iron symbiotic ores According to relevant reports at home and abroad, methods for extracting iron from high-iron red mud mainly include reduction sintering method, direct reduction method, magnetization roasting method and smelting method, but this process requires effective alumina and active alumina in the ore. The silicon oxide ratio is higher, and the current process of recovering iron from red mud is difficult to guarantee in terms of technical and economic benefits;

(3) Iron first and then aluminum, that is, blast furnace or electric furnace smelting iron/slag leaching and aluminum extraction process. This process can effectively separate iron and aluminum. This process generally uses aluminum-iron paragenetic ore directly for blast furnace ironmaking, or with high-grade Iron ore with low gangue content is blended and smelted by blast furnace; but the main problem is that if aluminum-iron symbiotic ore with high Al ₂ O ₃ content is used directly for blast furnace smelting, because the Al ₂ O ₃ in pellets or sinter Compared with ordinary pellets or sinter, the content of slag is greatly increased, which will cause the viscosity and melting point of the slag to increase, the fluidity of the slag will become poor, which will affect the smooth operation of the blast furnace, the desulfurization ability will drop sharply, the coke ratio will increase significantly, and the operation of the blast furnace will be difficult. Significant deterioration, although many researchers at home and abroad have carried out some useful explorations, by improving the quality of incoming raw materials, strengthening the smelting operation system, and using it in conjunction with high-grade iron ore to inhibit the excessive Al ₂ O ₃ content from sintering and ironmaking However, the effect is not satisfactory, the production cost is greatly increased, and there are great limitations in industrial application, which cannot fundamentally solve the problem that the aluminum-iron symbiotic ore is difficult to smelt in the blast furnace.

To sum up, although scholars at home and abroad have conducted extensive research on the separation of aluminum and iron in Al-Fe paragenetic ores, there is still a lack of economical and effective separation methods for Al-Fe paragenetic ores with complex intercalation relationships. In fact, to solve this problem, the overall metallurgical process must be reconsidered. A reasonable solution is to not only ensure the efficient dissociation and extraction of iron and aluminum technically, but also be economically feasible in terms of benefits. Therefore, in order to comprehensively utilize this kind of aluminum-iron symbiotic ore resources with abundant reserves, to develop efficient and economical iron-aluminum separation technology and process, and to improve the utilization rate of aluminum-iron symbiotic ore, the present invention is proposed.

Contents of the invention

Aiming at the above problems, the present invention proposes a process of adopting gas-based pre-reduction-high-temperature final reduction melting-preparation of calcium aluminate slag-extraction of alumina, thereby fundamentally solving the problem of iron, iron, It is difficult to effectively separate aluminum, and realize the complete separation of valuable elements of iron and aluminum contained in a large number of refractory and sluggish aluminum-iron symbiotic ores.

The present invention provides a method for melting and separating iron and aluminum of aluminum-iron paragenetic ore with complex embedding and refractory separation. The method comprises the following steps: loading the aluminum-iron paragenetic ore into a pre-reduction furnace, and then feeding carbon monoxide into the pre-reduction furnace and/or hydrogen to partially reduce the Al-Fe paragenetic ore, and then put the partially reduced Al-Fe paragenetic ore into the final reduction smelting furnace for further final reduction through carbon heat and high temperature, using molten iron at high temperature and The specific gravity of slag containing alumina is different to form upper and lower liquid phases to discharge iron and slag respectively, so as to complete the melting separation.

According to the iron-aluminum melting separation method of the present invention, wherein, the step of partially reducing the aluminum-iron paragenetic ore may include: directly adding the aluminum-iron paragenetic ore from the upper part of the pre-reduction furnace, and simultaneously feeding reduction gas into the lower part of the pre-reduction furnace, The reducing gas temperature ranges from 750°C to 950°C, and the reduction potential ranges from 0.6 to 1.0, so as to produce metallized aluminum-iron symbiotic pellets with a metallization rate in the range of 40%-90%.

According to the iron-aluminum melting separation method of the present invention, wherein, the final reduction step may include: feeding the metallized aluminum-iron symbiotic pellets into the final reduction and melting furnace through the feeding pipe of the pre-reduction furnace, and simultaneously Add lump coal at a ratio of 20% to 40% of the fuel weight ratio, and add limestone flux appropriately according to the content of alumina and silica in the ore, so as to keep the alkalinity in the slag at CaO/SiO ₂ =1.2±0.3, CaO /Al ₂ O ₃ = within the range of 1.2±0.2; and inject oxygen and coal powder with a purity greater than 90% into the final reduction melting furnace through the coal-oxygen injection system, and the coal ratio is 60% to 80% of the total fuel ratio Proportional injection, the fuel ratio is 750±200kg/tHM, and oxygen is injected into the upper part of the reactor at the same time, and the gas temperature in the furnace is controlled by adjusting the ratio of oxygen injected into the upper and lower parts of the final reduction melting furnace and the secondary combustion rate of gas And the degree of oxidation of the gas, the secondary combustion rate is controlled within the range of 5% to 45%, and the corresponding temperature of the slag in the furnace is 1650±150°C.

According to the iron-aluminum melting separation method of the present invention, the total iron grade of the aluminum-iron paragenetic ore may be above 25% by weight.

According to the method for melting and separating iron and aluminum of the present invention, the pre-reduction furnace may include a fluidized bed, a shaft furnace, a rotary hearth furnace or a rotary kiln, and the final reduction and smelting furnace may be an oxygen-coal smelting reduction furnace.

According to the iron-aluminum melting separation method of the present invention, the method may further include the step of adding lime to the discharged slag to generate calcium aluminate slag ore phase. Preferably, the step of adding lime to the discharged slag to generate calcium aluminate slag mineral phase may be to discharge the high-temperature alumina-containing slag in the final reduction melting furnace into the slag mineral phase adjustment device, and Lime is added thereto, and the amount of lime added must ensure that the alkalinity in the slag is within the range of CaO/SiO ₂ =2.0±0.1, CaO/Al ₂ O ₃ =1.4±0.2, so that the weight ratio of the mineral phase of the product More than 90% is calcium aluminate slag.

According to the iron-aluminum melting separation method of the present invention, the method may further include the step of hydrogen-enriched upgrading of the high-temperature gas generated in the final reduction step. Preferably, the hydrogen-enriched upgrading step may include: first dedusting the high-temperature gas through a hot cyclone dust collector, re-injecting the dust into the final reduction melting furnace through an oxygen-coal injection system, and purifying the high-temperature gas through a hot cyclone dust collector Enter the high-temperature coal gas hydrogen-rich reforming furnace, and add cold gas or natural gas of similar composition to the high-temperature gas hydrogen-rich reforming furnace to realize reforming or use the physical heat of high-temperature gas to chemically react with the red-hot carbon bed to convert the oxidative Gases CO ₂ and H ₂ O are transformed into reducing gases CO and H ₂ , increasing the reduction potential chemical energy of the coal gas and making it rich in hydrogen.

According to the iron-aluminum melting separation method of the present invention, the method may further include a tail gas treatment and recovery step of separating and utilizing carbon dioxide through a carbon dioxide separation and capture device.

Compared with the prior art, the advantages and/or characteristics of the present invention mainly include the following aspects:

(1) The present invention can completely separate the two most important elements, iron and aluminum, in the complex and difficult-to-select aluminum-iron paragenetic ore, and realize the comprehensive utilization of complex and difficult-to-select aluminum-iron paragenetic ore; the process can directly produce high-quality For molten iron, the recovery rate of iron is above 95%, and the traditional iron and steel metallurgical process can be used to obtain iron and steel products in the follow-up; in addition, the process is completed at the same time as iron smelting, and the mineral conditions for extracting alumina are completed to provide a mineral phase basis for further extraction of alumina;

(2) The smelting reduction process is used to replace the blast furnace ironmaking, and the three processes of coking, sintering and blast furnace smelting are shortened to the smelting reduction process, which simplifies the production process and improves production efficiency; and the dependence of the entire process on coke will be removed, and coal will be used instead Coke can directly produce molten iron and effectively use energy, which can reduce the dependence of the iron and steel industry on coking coal resources, and will significantly reduce the smelting cost of ironmaking production;

(3) Since this process adopts pure oxygen technology, the tail gas does not contain nitrogen and _NOx , which is more conducive to the separation, capture and storage of _CO2 . This process can significantly reduce the emission of harmful _NOx and greenhouse gas _CO2 , and The main components of the spoil after leaching Al ₂ O ₃ are 2CaO·SiO ₂ and CaCO ₃ , which can be used to produce cement without waste discharge, which is beneficial to environmental protection.

The invention can make the characteristic iron ore such as aluminum-iron symbiotic ore with rich reserves in my country become a strategic resource that can be smelted at low cost, and can effectively alleviate the external dependence of the iron ore source of my country's iron and steel industry. And with the increasingly tight supply of coking coal and stricter environmental protection requirements, the advantages of this study become more prominent. Therefore, the present invention realizes the complete separation and separate extraction of aluminum-iron symbiotic ore, adopts a new generation of smelting reduction slag iron separation technology that is beneficial to environmental protection, and realizes the concept of iron production and aluminum production centered on efficient utilization of resources and energy and technological innovations.

Description of drawings

Fig. 1 shows an example flow chart of an aluminum-iron symgenetic ore based on pre-reduction-final reduction smelting according to an exemplary embodiment of the present invention. In the attached drawings: 1 is the pre-reduction furnace, 2 is the final reduction melting furnace, 3 is the high-temperature coal gas hydrogen-rich upgrading furnace, 4 is the hot cyclone separator, 5 is the carbon dioxide separation and capture equipment, and 6 is the oxygen coal injection system , 7 is a slag mineral phase adjustment device, 8 is an alumina leaching and roasting device, and 9 is a cement production equipment.

Detailed ways

The present invention will be described in detail below in conjunction with each relevant device shown in the accompanying drawings.

There are mainly two reduction equipment used in the process of the present invention, one is the pre-reduction furnace 1 commonly used in metallurgical reduction, fluidized bed, shaft furnace, rotary hearth furnace or rotary kiln can be selected; the other core metallurgical equipment is final reduction melting The sub-furnace 2, which may be an oxygen-coal smelting reduction furnace, completes the separation of embedded complex refractory aluminum-iron symbiotic ore while ironmaking is carried out in the final reduction smelting furnace 2. The main process flow of the present invention is to load the aluminum-iron symbiotic ore powder or pellets into the pre-reduction furnace after mud washing, and then pass carbon monoxide and hydrogen into the pre-reduction furnace to reduce the powder ore or pellets. Iron oxides, and then put the fine ore or pellets that have been partially reduced in the gas phase into the final reduction smelting furnace, and further perform final reduction by carbothermal high temperature, using molten iron and alumina-containing slag at high temperature The specific gravity is different to form upper and lower liquid phases, and the iron and slag are discharged separately to realize the complete separation of metallic iron and slag; lime is added to the discharged slag, and the amount of lime added is controlled to make it chemically react and generate favorable The calcium aluminate slag phase of alumina is extracted to lay the mineral foundation conditions for the subsequent final extraction of alumina.

Example 1

Fig. 1 shows an example flow chart of an aluminum-iron symgenetic ore based on pre-reduction-final reduction smelting according to an exemplary embodiment of the present invention. As shown in Figure 1, this exemplary embodiment provides a method for melting and separating iron and aluminum from a complex and refractory Al-Fe paragenetic ore, the method comprising: loading the pellets of the Al-Fe paragenetic ore into a pre-reduction furnace 1, and then feed carbon monoxide and/or hydrogen into the pre-reduction furnace 1 to partially reduce the pellets of Al-Fe paragenetic ore, thereby forming pellets in which part of the iron oxide is reduced, that is, partially metallized Al-Fe paragenetic ore . Then put the partially reduced pellets into the final reduction smelting furnace 2, further carry out final reduction by carbothermal high temperature, and use the difference in specific gravity between molten iron and alumina-containing slag at high temperature to form an upper and lower two. A liquid phase phenomenon, iron and slag discharge, respectively, to complete the melting separation and recycling of iron and aluminum metals in complex embedded and refractory aluminum-iron symbiotic ores.

Example 2

According to an exemplary embodiment of the present invention, the iron-aluminum melting and separation method of complex embedded and refractory aluminum-iron paragenetic ore includes the following steps.

1. Pre-reduction of iron-containing minerals. The aluminum-iron symbiotic ore powder or pellets after mud washing are directly added from the upper part of the pre-reduction furnace 1, and the reduction gas is introduced into the lower part of the pre-reduction furnace 1 at the same time. The temperature range of the reduction gas is 750 ° C, and the reduction potential range is 0.6 . In the pre-reduction furnace 1, the iron-containing oxides in the aluminum-containing iron symbiotic pellets undergo a reduction reaction with carbon monoxide or hydrogen in the reducing gas, and a part of the iron-containing minerals are reduced to obtain a direct reduction with a metallization rate of 40%. Metallized aluminum-iron symbiotic pellets. Here, preferably, considering the sufficient saving of energy, the tail gas of the pre-reduction furnace 1 can be used to preheat the aluminum-containing iron symbiotic pellets to 200-250° C. and then loaded into the first pre-reduction furnace.

2. Iron-containing minerals are finally reduced and melted and separated. The direct reduction metallized aluminum-iron pellets are fed into the final reduction melting furnace 2 through the feeding pipe of the pre-reduction furnace 1, and at the same time, lump coal is added in a proportion of 20% of the total fuel weight ratio, and according to the alumina in the ore Add limestone flux moderately according to the content of silicon dioxide, so as to keep the alkalinity in the slag as CaO/SiO ₂ =0.9, CaO/Al ₂ O ₃ =1.0; Oxygen with a purity greater than 95% and pulverized coal for ordinary blast furnace injection are injected into the furnace 2, and the pulverized coal is injected in a proportion of 80% of the total fuel weight ratio, and the fuel ratio is about 550kg/tHM. Oxygen is injected, and the temperature of the gas in the furnace and the degree of oxidation of the gas are controlled by adjusting the ratio of the upper and lower parts of oxygen injected into the final reduction melting furnace 2 and the secondary combustion rate of the gas. The secondary combustion rate is controlled to be about 5%. The slag temperature in the furnace is about 1500°C, so that all the reduced metallic iron is melted into molten iron, and the slag is all in a molten state, and then the iron and slag are discharged separately to complete the final reduction of direct reduction metallized aluminum iron pellets Complete separation of slag and iron; at this time, the products of the final reduction melting furnace 2 include molten iron, gas and alumina-containing slag.

3. Alumina recovery from slag. The high-temperature alumina-containing slag in the final reduction melting furnace 2 is discharged into the slag ore phase adjustment device 7, and lime is added therein. The amount of lime added must ensure that the basicity of the slag is CaO/SiO ₂ = 1.9, CaO/Al ₂ O ₃ =1.2, so that 90% by weight of the mineral phase of the product is calcium aluminate slag, and the traditional alumina leaching and roasting device 8 is roasted for 3 hours to obtain alumina products. The main components of the corresponding waste residue are 2CaO·SiO ₂ and CaCO ₃ materials, which can be used to produce cement products through the cement production equipment 9 .

4. Hydrogen enrichment upgrading of high temperature gas. The final reduction melting furnace 2 of the present invention will also produce a large amount of high-temperature gas while obtaining molten iron and alumina-containing slag. The temperature of the gas is 1450°C. The method of hydrogen reforming furnace 3 to reform gas is to use the physical heat of high-temperature gas to chemically react with the hot carbon bed to transform oxidizing gases CO ₂ and H ₂ O into reducing gases CO and H ₂ , increasing the chemical reduction potential of the gas. Hydrogen-enriching can be carried out at the same time, the temperature of the gas is lowered to 950°C after reforming, and the cooled gas is dedusted by the hot cyclone dust collector 4, and the dust can be re-injected into the final reduction melting furnace 2 through the oxygen-coal injection system 6, Part of the gas purified by the hot cyclone dust collector 4 can enter the pre-reduction furnace 1 to provide reducing agent and heat for the pre-reduction furnace.

5. Exhaust gas treatment. The tail gas produced after the pre-reduction reaction of the materials in the pre-reduction furnace 1 only contains carbon monoxide, carbon dioxide, hydrogen and water vapor, and the carbon dioxide can be separated through the carbon dioxide separation and capture device 5. Another part of the excess gas produced by the quality furnace 3 is drawn out through pipelines, which can be supplied to users outside the system, or partly supplied to the subsequent alumina leaching and roasting device 8. Part of the captured carbon dioxide can be provided to other chemical users, and part of it can be stored , and the other part can also be supplied to the alumina leaching and roasting device 8 in the subsequent process of this process.

Example 3

This embodiment is basically the same as Embodiment 2, except that the temperature range of the reducing gas fed into the lower part of the pre-reduction furnace 1 is 950°C, and the reduction potential range is 1.0; the metal of the pellets reduced by the preheating reduction furnace 1 The conversion rate is 90%; in the final reduction step, the fuel ratio of the fuel consisting of 40% lump coal and 60% pulverized coal by weight is about 950kg/tHM, and the basicity of the slag is CaO/SiO ₂ = 1.5, CaO/Al ₂ O ₃ = 1.4, the secondary combustion rate is controlled to be about 45%, and the corresponding slag temperature in the furnace is about 1800°C; in the step of recovering alumina from the slag, the basicity of the slag is CaO/SiO ₂ =2.1, CaO/Al ₂ O ₃ =1.6, the resulting product contains 98% by weight of calcium aluminate slag, and the roasting time is 2 hours; The temperature is 1850°C, and the method of gas upgrading is as follows: mixing cold coal gas or natural gas with similar composition in the reforming furnace to realize the reforming, while completing the cooling, the reduction potential and hydrogen-rich degree of the gas are significantly improved, and the reformed coal gas After massaging, its temperature dropped to 750°C.

Example 4

In another exemplary embodiment according to the present invention, the iron-aluminum melting separation method of complex embedded and refractory aluminum-iron paragenetic ore includes the following steps.

1. Grinding and granulating. The aluminum-iron symbiotic ore raw material containing 41.2% Fe ₂ O ₃ , 27.5% Al ₂ O ₃ , and the aluminum-silicon ratio A/S in the ore is about 3 is crushed into 8mm powder ore by crushing equipment, and then the ore is ground Make it pulverized to a mineral powder with a particle size of 0.06mm, and then wash the mineral powder for mud washing, and then mix the pulverized mineral powder after mud washing with ordinary mining pelletizing binder and water, and put it into the agglomeration equipment The pelletizing is carried out in the medium, and the diameter of the pellets is 15-35mm, forming aluminum-containing iron pellets with a relatively uniform particle size.

2. Pre-reduction of iron-containing minerals. The aluminum-containing iron pellets are preheated to about 230°C with the exhaust gas of the pre-reduction shaft furnace, and then loaded into the pre-reduction shaft furnace 1. At the same time, the reduction gas is introduced into the lower part of the pre-reduction shaft furnace 1. The temperature of the reduction gas is 800°C, and the reduction potential is 0.95. In the pre-reduction shaft furnace 1, the iron-containing oxides in the aluminum-containing iron pellets undergo a reduction reaction with carbon monoxide or hydrogen in the reducing gas, and a part of the iron-containing minerals are reduced to obtain a direct metallization rate of 80%. Reduction of metallized aluminum-iron pellets.

3. Final reduction and melting separation of iron-containing minerals. The directly reduced metallized aluminum-iron pellets enter the final reduction smelting furnace 2 through the feeding pipe of the pre-reduction shaft furnace 1, and at the same time add 200kg/tHM lump coal and 132.5kg/tHM limestone flux to increase the alkalinity of the slag. CaO/SiO ₂ =1.4, CaO/Al ₂ O ₃ =1.3; and through the coal-oxygen injection system 6, inject into the final reduction smelting furnace 2 a purity of 93% oxygen and pulverized coal for ordinary blast furnace injection, The coal ratio is 530kg/tHM. At the same time, oxygen is injected into the upper part of the reactor, and the temperature of the gas in the furnace and the degree of oxidation of the gas are controlled by adjusting the ratio of oxygen injected into the upper and lower parts of the final reduction melting furnace 2 and the secondary combustion rate of the gas. , the secondary combustion rate is controlled at 25%, and the corresponding slag temperature in the furnace is 1650°C, so that all the reduced metallic iron is melted into molten iron, and all the slag is in a molten state, and then the iron and slag are discharged separately to complete the direct The final reduction of metallized aluminum-iron pellets and the complete separation of slag and iron; at this time, the products of the final reduction melting furnace 2 include molten iron, gas and alumina-containing slag.

4. Alumina recovery from slag. Discharge the high-temperature alumina-containing slag in the final reduction melting furnace 2 into the slag ore phase adjustment device 7, and add lime to it, and mix the lime so that CaO/SiO ₂ = 2.0, CaO/Al ₂ in the slag O ₃ =1.4, 100% of the product is calcium aluminate slag, which is roasted for 2.5 hours in the traditional alumina leaching and roasting device 8 to obtain alumina products, and the main components of the corresponding waste slag are 2CaO·SiO ₂ and CaCO ₃ Material, can produce cement product through cement production equipment 9.

5. Hydrogen enrichment upgrading of high temperature gas. The high-temperature gas produced by the final reduction melting furnace 2 first enters the high-temperature gas hydrogen-rich reforming furnace 3, and the temperature of the gas is reduced to 800°C after reforming. The blowing system 6 is re-sprayed into the final reduction smelting furnace 2, and the gas purified by the hot cyclone dust collector 4 enters the pre-reduction shaft furnace 1 to provide reducing agent and heat for the pre-reduction shaft furnace 1.

6. Exhaust gas treatment. The tail gas produced after the pre-reduction reaction of the materials in the pre-reduction shaft furnace 1 contains only carbon monoxide, carbon dioxide, hydrogen and water vapor, and the carbon dioxide is separated through the carbon dioxide separation and capture device 5. Another part of excess gas produced by the quality furnace 3 is drawn out through pipelines and supplied to users outside the system. 30% of the captured carbon dioxide is provided to other chemical users, and the other 70% is supplied to the alumina leaching and roasting device 8 in the subsequent process of this process.

To sum up, the main feature of this process is the process of air-based pre-reduction-high-temperature final reduction-preparation of calcium aluminate slag-leaching and roasting to extract alumina after pelletizing the aluminum-iron symbiotic ore. The significant difference between the process of the present invention and other processes or inventions is that the final reduction and melting can realize the complete separation of iron and aluminum in refractory complex aluminum-iron symbiotic ores, and at the same time ensure the high recovery rate of iron and aluminum, and realize complex refractory aluminum Comprehensive utilization of iron symbiotic ore, the process of the present invention has neither waste gas nor waste slag discharge, and the products that can be obtained include iron, alumina, high-quality gas, cement and carbon dioxide. The process of the present invention is a clean production process with low energy consumption and high recovery rate .

Claims (10)

1. A kind of embedding complex, refractory aluminum-iron paragenetic ore iron-aluminum melting separation method is characterized in that comprising the following steps: Put the Al-Fe ore into the pre-reduction furnace (1), then feed carbon monoxide and/or hydrogen into the pre-reduction furnace (1) to partially reduce the Al-Fe ore, and then put the partially reduced Al-Fe ore into the pre-reduction furnace (1) Put it into the final reduction smelting furnace (2), and further perform final reduction through carbon heat and high temperature, and use the difference in specific gravity between molten iron and alumina-containing slag at high temperature to form two liquid phases, the upper and lower liquid phases, respectively, for iron tapping and slag discharge , to complete the melt separation. 2. The iron-aluminum melting and separation method of aluminum-iron paragenetic ore according to claim 1, characterized in that, the step of partially reducing the aluminum-iron paragenetic ore comprises: direct the aluminum-iron paragenetic ore from the upper part of the pre-reduction furnace (1) Adding, and at the same time, reducing gas is introduced into the lower part of the pre-reduction furnace (1), the temperature range of the reducing gas is 750°C-950°C, and the range of the reduction potential is 0.6-1.0, so as to obtain a metallization rate in the range of 40%-90%. Metallized aluminum-iron symbiotic pellets. 3. The method for melting and separating iron and aluminum of aluminum-iron symbiotic ore according to claim 1, characterized in that, the final reduction step comprises: passing metallized aluminum-iron symbiotic pellets through the feeding pipe of the pre-reduction furnace (1) Send it into the final reduction melting furnace (2), add lump coal at a ratio of 20% to 40% of the total fuel weight ratio, and add limestone flux appropriately according to the content of alumina and silicon dioxide in the ore to maintain The basicity in the molten slag is within the range of CaO/SiO ₂ =1.2±0.3, CaO/Al ₂ O ₃ =1.2±0.2; Oxygen and pulverized coal with a purity greater than 90%, the coal ratio is injected according to the ratio of 60% to 80% of the total fuel ratio, and the fuel ratio is 750±200kg/tHM, and oxygen is injected into the upper part of the reactor, and the final reduction is achieved by adjusting the injection The proportion of oxygen in the upper and lower parts of the melting furnace (2) and the secondary combustion rate of the gas control the temperature of the gas in the furnace and the oxidation degree of the gas. The secondary combustion rate is controlled within the range of 5% to 45%. The slag temperature is at 1650±150°C. 4 . The method for melting and separating iron and aluminum of the aluminum-iron paragenetic ore according to claim 1 , wherein the total iron grade of the aluminum-iron paragenetic ore is above 25% by weight. 5. The method for melting and separating iron and aluminum of aluminum-iron symbiotic ore according to claim 1, characterized in that, the pre-reduction furnace (1) comprises a fluidized bed, a shaft furnace, a rotary hearth furnace or a rotary kiln, and the final reduction The smelting furnace (2) is an oxygen-coal smelting reduction furnace. 6. The method for melting and separating iron and aluminum of aluminum-iron paragenetic ore according to any one of claims 1 to 5, characterized in that, the method also includes adding lime to the discharged slag to generate calcium aluminate slag ore phase A step of. 7. The aluminum-iron paragenetic ore iron-aluminum melting separation method according to claim 6, characterized in that, the step of adding lime to the discharged slag to generate the calcium aluminate slag ore phase is to convert the final reduction melting furnace The high-temperature alumina-containing slag in (2) is discharged into the slag ore phase adjustment device (7), and lime is added thereto. The amount of lime added must ensure that the alkalinity in the slag is at CaO/SiO ₂ =2.0± 0.1, CaO/Al ₂ O ₃ =1.4±0.2, so that more than 90% of the mineral phase of the product is calcium aluminate slag by weight. 8. The method for melting and separating iron and aluminum of aluminum-iron paragenetic ore according to any one of claims 1 to 5, characterized in that, the method also includes hydrogen-rich upgrading of the high-temperature gas produced in the final reduction step step. 9. The method for melting and separating iron and aluminum in aluminum-iron symbiotic ore according to claim 8, characterized in that, the hydrogen-enriched upgrading step comprises: first dedusting the high-temperature gas through a hot cyclone dust collector (4), and the dust passes through the oxygen coal The injection system (6) is re-injected into the final reduction melting furnace (2), and the high-temperature gas purified by the hot cyclone dust collector (4) enters the high-temperature gas hydrogen-rich upgrading furnace (3), and is transferred to the high-temperature gas hydrogen-rich reformer. The quality furnace (3) is mixed with cold gas or natural gas of similar composition to achieve upgrading or to use the physical heat of high-temperature gas to chemically react with the hot carbon bed to convert the oxidizing gas CO ₂ and H ₂ O into the reducing gas CO and H ₂ , increase the reduction potential chemical energy of the gas and make it rich in hydrogen. 10. The method for melting and separating iron and aluminum of aluminum-iron symbiotic ore according to any one of claims 1 to 5 or 7 or 9, characterized in that, the method also includes carbon dioxide separation and capture equipment (5) Tail gas treatment and recovery steps for separation and utilization.

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