CN108588411A - A kind of preparation method of the high-carbonaceous metallized agglomerate of blast furnace - Google Patents

Abstract

The invention discloses a method for preparing a high-carbon-containing metallized agglomerate for a blast furnace, which belongs to the technical field of ironmaking. The raw materials are composed of ultra-fine iron ore concentrate, anthracite coal powder and weakly caking bituminous coal powder. The average particle size of iron ore powder is 1-5μm, and the average particle size of mixed coal powder is 50-100μm. After the raw materials are fully mixed, after adding a certain proportion of organic binder and water, use a ball press to press to form a raw mass. Then, it is roasted according to a certain temperature regime under the conditions of air isolation or N ₂ protection to prepare high-carbon metallized agglomerates. The carbon content of the high-carbon-containing metallized agglomerate of the present invention is 20-40 wt%, and has good cold strength, crushing strength after reaction and good CO ₂ reactivity. In blast furnace production, adding an appropriate proportion of high-carbon metallized agglomerates to the iron-containing mineral material layer is beneficial to reduce the coke ratio and energy consumption of the blast furnace without affecting the air permeability of the blast furnace. Since the carbon source of high-carbon metallized agglomerates comes from weakly cohesive bituminous coal and anthracite, it is beneficial to expand the use of non-coking coal in blast furnace ironmaking and reduce the dependence of blast furnace ironmaking on coke.

Description

A kind of preparation method of high-carbon-containing metallized agglomerate for blast furnace

technical field

The invention belongs to the field of iron and steel metallurgy, and relates to a method for preparing high-carbon-containing metallized agglomerates for blast furnace ironmaking.

Background technique

Blast furnace ironmaking is the main molten iron production process in the world. Coke is the most important raw material for blast furnaces in terms of improving the operating efficiency of blast furnaces and controlling the quality of molten iron. Coke constitutes a major part of the production costs of hot metal. Due to the lack of coking coal resources and coking is a highly polluting industry, low coke ratio ironmaking technology has always been an important research content of blast furnace ironmaking.

In blast furnace ironmaking, coke has the following three functions, namely: thermal function, as a fuel to provide heat for chemical reactions and molten iron and slag; chemical function, as a reducing agent to provide reducing gas for reducing iron-containing minerals; mechanical function, As a skeleton, it provides support for the iron-containing charge, so that liquid and gas can pass through the furnace, especially the lower part of the blast furnace. During the descent of the coke in the blast furnace, the coke is exposed to extreme reaction conditions. When the temperature rises to about 800°C, coke reacts with carbon dioxide produced by iron mineral reduction; when the temperature rises to 1200°C, coke reacts with liquid FeO and SiO ₂ and carburizes molten iron; when the temperature is high At 1500°C, the coke reacts with the oxygen in the hot air near the blast furnace roundabout. In the past few decades, a lot of research has been done on low coke ratio blast furnace ironmaking technology. The main technology in this area is blast furnace coal injection, which realizes partial substitution of non-coking coal for the consumption of coke in the roundabout area. At present, through the use of pulverized coal combustion catalyst, oxygen-enriched air blast and high air temperature, the amount of coal injection per ton of iron can reach 200kg. There are many difficulties to further increase the amount of coal injection per ton of iron, for example, further increasing the amount of coal injection per ton of iron will significantly affect the gas permeability and gas flow behavior in the lower part of the blast furnace. In the shaft area of the blast furnace at a temperature of 800-1200°C, about 10-20% of the coke consumption is due to carbon dissolution reactions. There are fewer technologies to reduce coke consumption in this area. Some researchers proposed to slow down coke gasification by adding passivation agent to coke, but the effect of passivation agent is not obvious. Secondly, some researchers also proposed to use high gasification iron coke to suppress coke gasification, but still need to mix a part of strong caking coal in the preparation process of iron coke (Chinese patent, CN 102827624 B, Chinese patent CN 104119939 B). Therefore, the coke-saving technology in the temperature range of 800-1200 °C is worthy of further study.

Metallized agglomerates (metallized pellets) have now partially replaced traditional blast furnace iron-bearing charges consisting of lump ore, sinter and pellets. The main purpose of adding a part of metallized agglomerates to the blast furnace iron-containing charge is to increase the productivity of the blast furnace. Metallized agglomerates are usually prepared by direct reduction of cold-solidified internally complexed carbon agglomerates. The carbon content in metallized agglomerates (pellets) is currently about 2.0-4.0 wt%. If the carbon content of the metallized agglomerates can be greatly increased without destroying the strength of the metallized agglomerates, the carbon in the metallized agglomerates can also be gasified in the coke dissolution reaction zone (800-1200°C) of the blast furnace. This can make the high-carbon-containing metallized pellets further have the function of iron coke, realize the improvement of the CO content of the blast furnace gas and promote the reduction of the iron-containing charge. In addition, due to the low carbon content in the high-carbon metallized agglomerate, when the agglomerate falls to the reflow zone with the iron ore charge, most of the carbon in it has been gasified, and its carbon content drops to that of ordinary metallized balls. Therefore, it will not bring carbon residue particles into the lower part of the blast furnace, that is, it will not affect the gas permeability of the lower part of the blast furnace.

Contents of the invention

The object of the present invention is to provide a method for preparing high-carbon-containing metallized agglomerates for blast furnace ironmaking. The present invention intends to use ultra-fine iron ore powder and non-coking coal coal powder to prepare raw agglomerates + isolate the technical route of air or roast in an inert atmosphere. In the present invention, the high mechanical strength and high gasification performance of the high-carbon-containing metallized agglomerate are realized through the control of the particle size of the raw material and the control of the roasting temperature and atmosphere. Ensure that the prepared metallized agglomerate has high strength in the blast furnace and can maintain the gas permeability of the charge inside the blast furnace.

The technical proposal of the present invention is a method for preparing high-carbon metallized agglomerates for blast furnaces, including the preparation of raw materials and the roasting of the agglomerates. The preparation method includes:

A method for preparing a high-carbon-containing metallized block for blast furnaces, the method comprising the following steps:

Step 1, preparation of ultra-fine iron ore powder: crushing the iron ore and fully finely grinding it into iron ore powder with a ball mill;

Step 2, coal powder preparation: prepare the selected coal sample into coal powder;

Step 3. Mixing and briquetting of raw materials: Fully mix ultra-fine iron ore powder and coal powder according to the preset ratio, add a certain proportion of organic binder and water, and then press the raw agglomerate. The pressure used for pressing the agglomerate is 300 -400kg/cm ² , cold press forming to obtain a wet mass of Φ(15-20)mm×15-20mm;

Step 4, drying of raw agglomerates: fully drying the prepared raw agglomerates;

Step 5. Roasting the raw agglomerate: roasting the dried agglomerate under a certain atmosphere and a certain temperature regime.

Further, in the first step, the total iron content of the iron ore is greater than 60wt%, and the average particle size of the ore powder is 1-5 μm.

Further, in the second step, the coal is a mixture of weakly caking bituminous coal and anthracite, the average particle size of the pulverized coal is 50-100 μm, the fixed carbon content of the pulverized coal is 65-75%, and the volatile 18-25%, the ash content is less than 10%.

Further, in the third step, when the mineral powder and coal powder are mixed, the mass ratio of mineral powder to coal powder is in the range of 1.5-2.0.

Further, in the third step, the amount of organic binder used in the process of pressing the agglomerate does not exceed 2% of the mass of the mixture, and the water content used does not exceed 10%. The organic binder includes cellulose and waste paper pulp.

Further, in the step 4, the drying temperature of the raw agglomerate is 100-200° C., and the drying time is 1-2 hours.

Further, in the step five, the atmosphere is _N2 atmosphere or isolated air; the temperature regime is that the furnace temperature rises from room temperature to 900-1000°C at a rate of 5-10°C/min, and at 900-1000°C After keeping warm for 30-60min at ℃, cool down to room temperature naturally.

Below, the good technical effects brought by the main content of the technical solution of the present invention are described in detail.

The high-carbon metallized agglomerate proposed by the invention can be used as an excellent raw material in blast furnace ironmaking, and the agglomerate has the following advantages.

(1) During the roasting process, the iron ore powder particles in the raw agglomerate are reduced by coal powder to ultrafine metal iron powder. These metal iron powders are distributed in the gaps between the carbon particles in a highly dispersed state, and adhere closely to the surface of the carbon particles. Therefore, the ultra-fine metal iron powder has a consolidation effect on the larger carbon particles from both mechanical and chemical effects. As a result, the high-carbon metallized agglomerate has good mechanical strength, which meets the requirements for the strength of the charge for blast furnace ironmaking.

(2) In the metallized agglomerate with high carbon content, iron is dispersed in the carbon matrix of the agglomerate. Since metallic iron can catalyze the gasification reaction of carbon, the discounted metallic iron powder forms many catalytic active points on the surface of carbon particles. Carbon in high-carbon metallized briquettes has a higher _CO2 reactivity than carbon in coke. When it is mixed with the iron-containing charge of the blast furnace in an appropriate proportion and charged into the furnace, the CO ₂ produced by the reduction of iron ore is quickly converted into CO by the carbon in the metallized agglomerates, so the high-carbon metallized agglomerates can improve the iron ore reduction conditions and improve blast furnace gas utilization.

(3) The CO ₂ produced by the reduction of iron minerals first reacts with the carbon in the metallized agglomerate for carbon gasification reaction, so the high carbon-containing metallized agglomerate mixed with the iron-containing mineral layer has a negative effect on the layered bulk coke. It also has a protective effect, so that the bulk coke entering the central coke layer has a larger particle size and strength, and improves the air and liquid permeability of the hearth and its surrounding areas.

(4) When the metallized agglomerate with high carbon content falls to the vicinity of the soft melting zone, since most of the carbon in it has been gasified, what remains in the agglomerate is mainly metallic iron and a small amount of gangue, which do not exist or rarely exist carbon particles. Therefore, its melting has no effect on the air permeability of the blast furnace reflow belt.

(5) The production process of high-carbon metallized agglomerates all uses non-coking coal, which has good effects in coal resource response measures and environmental protection measures in ironworks.

(6) The raw agglomerate adopts a cold pressing molding process and uses a small amount of cheap organic binder, so the cost is low and the pollution to the environment is less. At the same time, the production process of the invention is simple and has broad industrial application prospects.

Description of drawings

Fig. 1 is a process diagram for the preparation of high-carbon metallized agglomerates for blast furnaces of the present invention.

Figure 2 is the XRD pattern of the sample obtained in Example 1 of the present invention.

Figure 3(a) is the microscopic morphology of the sample obtained in Example 1 of the present invention; Figure 3(b) is the microscopic morphology of iron particles (white) and carbon particles (gray) in the obtained sample.

Figure 4 (a) is the microscopic appearance of the metallized pellets after high temperature reaction in Example 1 of the present invention; Figure 4 (b) is the metallized pellets after the high temperature reaction, wherein iron particles (white) and carbon particles (gray ) microscopic morphology.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings 1-4 and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. On the contrary, the invention covers any alternatives, modifications, equivalent methods and schemes within the spirit and scope of the invention as defined by the claims. Further, in order to make the public have a better understanding of the present invention, some specific details are described in detail in the following detailed description of the present invention. The present invention can be fully understood by those skilled in the art without the description of these detailed parts.

As shown in Figure 1, a method for preparing a high-carbon metallized agglomerate for a blast furnace specifically comprises the following steps:

Step 1. Preparation of ultra-fine iron ore powder: using iron ore concentrate raw material with a total iron content greater than 60wt%, after crushing and fully ball milling the iron ore concentrate, the average particle size of the obtained ore powder is 1-5 μm.

Step 2. Coal powder preparation: taking weak caking coal and anthracite as raw materials, crushing the coal sample with a crusher and a ball mill, ball milling and fully mixing, the average particle size of the obtained mixed coal powder is 50-100 μm.

Step 3. Mixing and briquetting of raw materials: Mix the prepared ultra-fine iron ore powder and coal powder in a certain proportion, add a certain proportion of organic binder and water to the mixed material, and then use a double-roller briquetting machine Pressed into agglomerates with a size of Φ(15-20mm)×15-20mm, wherein the binder is an organic binder, and the amount of organic binder used in the ball making process does not exceed 2%, and the water content used does not exceed 10% .

In this step, when the mineral powder and coal powder are mixed, the mass ratio of mineral powder to coal powder is 1.5-2.0.

Step 4. Drying of raw agglomerates: In order to ensure the dryness of the raw agglomerates, the agglomerates can be dried naturally at 100-200° C. for 1-2 hours after natural drying for 24 hours to achieve full drying.

Step 5. Roasting of raw agglomerates: the dried agglomerates are roasted under a certain temperature regime and a certain atmosphere.

In this step, the temperature system for roasting the raw agglomerate is that the furnace temperature rises from room temperature to 900-1000° C. at a rate of 5-10° C., and after being kept at 900-1000° C. for 30-60 minutes, the furnace temperature is naturally cooled to room temperature. During the firing process, the atmosphere is isolated from air or protected by inert gas. The carbon content of the resulting metallized agglomerate is 20-40 wt%. During the slow roasting process, the ultra-fine iron oxide powder in the agglomerate is fully reduced during the roasting process, and the reaction between the iron ore powder and the coal powder particles will not be too intense to cause deformation of the agglomerate or cracks on the surface. The main phases in the agglomerate are metallic iron and carbon (as shown in Figure 2). Due to the extremely fine particle size of the iron ore powder used, the fine-grained metallic iron particles in the agglomerate after roasting are highly dispersed in the carbon matrix (as shown in Figure 3(a)). At the same time, it can be seen from Figure 3(b) that the size of these fine-grained metallic iron particles is less than 10μ, far smaller than the particle size of carbon particles; and tightly attached to the surface of carbon particles. From the microscopic analysis, the strength of the agglomerate comes from the interface where iron particles and coke particles are in close contact. On the interface, the surface of coke particles is uneven, with many micropores and cracks; the surface of metallic iron particles also has many fine (nanoscale) iron whiskers. These fine iron whiskers can be embedded in the pits and micropores on the surface of coke particles, which provide good conditions for the mechanical twisting of the interface between coke particles and metal iron particles, and the metal iron particles can be anchored on the surface of coke particles. At the same time, atomic diffusion will occur on the interface between coke particles and iron particles during high-temperature roasting to form compounds such as Fe ₃ C, so there will be partial fusion between the surface of coke particles and the surface of metallic iron, that is, iron-carbon also exists on the interface The strength of chemical bonds between atoms. For adjacent coke particles, these extremely fine-grained metal iron powders essentially act as a bond. The cohesive force of a single iron particle to coke particles is very weak, but the cohesive force of a large number of iron particles dispersed in the whole agglomerate is very considerable, thus effectively improving the strength and toughness of the whole agglomerate .

If high carbon-containing metallized agglomerates are used as blast furnace charge, its cold strength and crushing strength after screening must meet the requirements of blast furnace charge. After reacting for 1 hour under the conditions of simulating the environment in the high temperature zone of a blast furnace (temperature: 1100°C, atmosphere: CO:CO ₂ =4:1, gas flow rate: 1m/s), the microscopic morphology of the metallized agglomerate is shown in Figure 4 ( As shown in a), comparing Figure 3(a) and Figure 4(a), it can be seen that the particle size of the iron particles in the agglomerate after the reaction becomes significantly larger. Figure 4(b) shows the microscopic morphology of carbon particles and metallic iron in the agglomerate after the reaction. It can be seen that the metallic iron particles aggregate on the surface of the carbon particles, indicating that a metallic iron network is gradually formed inside the agglomerate during the reaction process. structure. The aggregation of metal iron particles and the formation of a network structure effectively improve the crushing strength of the agglomerates after reaction, so the agglomerates will not be pulverized in the high temperature area of the blast furnace.

Below in conjunction with specific examples the method of the present invention is described in further detail, the chemical composition of iron concentrate used in the embodiment of the present invention is as shown in Table 1, the coal sample used is as shown in Table 2-3, and Table 4 is the coke composition for comparison .

Table 1. Iron concentrate chemical composition (wt%)

Table 2. Industrial analysis of weakly caking bituminous coal (Shenhua bituminous coal) (wt%)

Table 3. Industrial analysis of anthracite (Jiaozuo anthracite) (wt%)

Table 4. Industrial analysis of ordinary metallurgical coke for comparison (wt%)

Embodiment one

[1]. Preparation of ultra-fine iron ore powder: Table 1 shows the chemical analysis results of the iron ore concentrate used. Take 600g of iron ore concentrate, after the iron ore concentrate sample is crushed and fully ball milled, the average particle size of the obtained ore powder is 2.88 μm.

[2]. Coal powder preparation: Table 2 shows the industrial analysis results of the bituminous coal used, and Table 3 shows the industrial analysis results of the anthracite used. Take 150g of the above-mentioned bituminous coal sample and 150g of the above-mentioned anthracite sample. After crushing, ball milling and mixing the two coal samples, the average particle size of the mixed coal powder is 60 μm.

[3]. Mixing and briquetting of raw materials: fully mix the above-mentioned iron ore powder and mixed coal powder. The mixed material is made into agglomerates with a diameter of Φ15mm×15mm. Each mass has a mass of 5-6 g. The ball-making binder uses 2.0% cellulose.

[4]. Drying of raw agglomerates: After natural drying of raw agglomerates for 24 hours, further drying at 100° C. for 1 hour.

[5]. Roasting of raw agglomerates: using a tube furnace, roasting under the following conditions: the furnace temperature rises from room temperature to 1000 °C at a rate of 5 °C/min; after holding at 1000 °C for 30 min, cool to room temperature. During the roasting process, N ₂ was fed into the furnace at a volume flow rate of 500 ml/min. The carbon content of the resulting high carbon metallized agglomerates was 25 wt%.

According to the national standard GB/T14201-93 standard test, the cold strength of the obtained metallized agglomerate is 2000N/piece. Under the conditions of simulating the high-temperature zone environment in the blast furnace (temperature: 1100°C, atmosphere: CO:CO ₂ =4:1, gas flow rate: 1m/s), after 1 hour of reaction of 100g agglomerate sample, the reaction of this sample The crushing strength is 2500N/piece. Under the conditions of simulating the high-temperature area of a blast furnace (temperature: 1100°C, atmosphere: CO:CO ₂ =4:1, gas flow rate: 1m/s), the carbon gasification rate of 100g of agglomerates after 1 hour of reaction 70%. As a comparison, under the same reaction conditions, the carbon gasification rate of 100g of ordinary coke (composition shown in Table 4) with the same average particle size is 10%.

Embodiment two

[1]. Preparation of ultra-fine iron ore powder: Table 1 shows the chemical analysis results of the iron concentrate used. Take 600g of iron ore concentrate sample, and after preliminary crushing and full ball milling of the iron ore concentrate sample, the average particle size of the obtained iron ore powder is 3.56 μm.

[2]. Coal powder preparation: Table 2 shows the industrial analysis results of the bituminous coal used, and Table 3 shows the industrial analysis results of the anthracite used. Take 200g of the above-mentioned bituminous coal sample and 200g of the above-mentioned anthracite sample. After crushing, ball milling and mixing the two coal samples, the average particle size of the obtained mixed coal powder is 60 μm.

[3]. Mixing and briquetting of raw materials: fully mix the above-mentioned iron ore powder and mixed coal powder. The mixed material is pressed into a mass of Φ15mm×15mm. Each mass has a mass of 5-6 g. The ball-making binder uses 2.0% cellulose.

[4]. Drying of raw agglomerates: after natural drying of raw agglomerates for 24 hours, further drying at 100° C. for 2 hours.

[5]. Roasting of raw agglomerates: using a tube furnace, roasting under the following conditions: the furnace temperature rises to 1000°C at a heating rate of 10°C/min; after holding at 1000°C for 60 minutes, it is naturally cooled to room temperature. During the roasting process, N ₂ was fed into the furnace at a volume flow rate of 500 ml/min. The carbon content of the resulting metallized agglomerate was 33.0 wt%.

Tested according to the national standard GB/T14201-93, its cold strength is 1500N/piece. Under the conditions of simulating the high-temperature zone environment in the blast furnace (temperature: 1100°C, atmosphere: CO:CO ₂ =4:1, gas flow rate: 1m/s), after 1 hour of reaction of 100g agglomerate sample, the reaction of this sample The crushing strength is 2000N/piece. Under the conditions of simulating the high-temperature area of a blast furnace (temperature: 1100°C, atmosphere: CO:CO ₂ =4:1, gas flow rate: 1m/s), the carbon gasification rate of 100g of agglomerates after 1 hour of reaction 60%. As a comparison, under the same reaction conditions, the gasification rate of carbon in 100 g of ordinary coke (composition shown in Table 4) with the same average particle size is 10%.

Embodiment three

[1]. Preparation of ultra-fine iron ore powder: Table 1 shows the chemical analysis results of the iron concentrate used. Take 600g of iron concentrate sample. After the iron ore concentrate sample is crushed and fully ball milled, the average particle size of the obtained iron ore powder is 4.82 μm.

[2]. Coal powder preparation: Table 2 shows the industrial analysis results of the bituminous coal used, and Table 3 shows the industrial analysis results of the anthracite used. Take 150g of the above-mentioned bituminous coal sample and 150g of the above-mentioned anthracite sample. After crushing, ball milling and mixing the two coal samples, the average particle size of the mixed coal powder is 100 μm.

[3]. Mixing and briquetting of raw materials: fully mix the above-mentioned iron ore powder and mixed coal powder. The mixed material is pressed into a mass of Φ20mm×20mm. Each mass has a mass of 9-11 g. The ball binder uses 2.0% waste paper pulp.

[4]. Drying of raw agglomerates: after natural drying of raw agglomerates for 24 hours, further drying at 200° C. for 1 hour.

[5]. Roasting of raw agglomerates: using a tube furnace, roasting under the following conditions: the furnace temperature rises to 1000°C at a heating rate of 10°C/min; after holding at 1000°C for 30 minutes, it is naturally cooled to room temperature. During the roasting process, the furnace is isolated from air. The carbon content of the resulting metallized agglomerates was 24% by weight.

Tested according to the national standard GB/T14201-93, its cold strength is 1500N/piece. Under the conditions of simulating the high-temperature area in the blast furnace (temperature: 1100°C, atmosphere: CO:CO ₂ =4:1, gas flow rate: 1m/s), after 1 hour of reaction of 100g agglomerate sample, the post-reaction resistance of the sample The crushing strength is 3000N/piece. Under the conditions of simulating the high temperature zone environment in the blast furnace (temperature: 1100°C, atmosphere: CO:CO ₂ =4:1, gas flow rate: 1m/s), after 1 hour of reaction of 100g agglomerate sample, the carbon gas of the sample The transformation rate is 65%. As a comparison, under the same reaction conditions, the gasification rate of ordinary coke with the same average particle size (composition shown in Table 4) was 8%.

Embodiment four

[1]. Preparation of ultra-fine iron ore powder: Table 2 shows the chemical analysis results of the iron ore concentrate used. Take 600g of iron ore concentrate sample, after the iron ore concentrate sample is crushed and fully ball milled, the average particle size of the obtained iron ore powder is 1.50 μm.

[2]. Coal powder preparation: Table 2 shows the industrial analysis results of the bituminous coal used, and Table 3 shows the industrial analysis results of the anthracite used. Take 200g of the above-mentioned anthracite sample and 200g of the above-mentioned bituminous coal sample. After crushing, ball milling and mixing the two coal samples, the average particle size of the mixed coal powder is 80μm.

[3]. Mixing and briquetting of raw materials: fully mix the above-mentioned iron ore powder and mixed coal powder. The mixed material is pressed into agglomerates with a diameter of Φ20mm×20mm. Each mass has a mass of 9-11 g. The ball binder uses 2.0% waste paper pulp.

[4]. Drying of raw agglomerates: after natural drying of raw agglomerates for 24 hours, further drying at 100° C. for 2 hours.

[5]. Roasting of raw agglomerates: using a tube furnace, roasting under the following conditions: the furnace temperature rises to 900°C at a heating rate of 5°C/min; after holding at 900°C for 30 minutes, it is naturally cooled to room temperature. During the roasting process, N ₂ was fed into the furnace at a volume flow rate of 500 ml/min. The carbon content of the resulting metallized agglomerate was 37% by weight.

According to the national standard GB/T14201-93 test, the cold strength of the agglomerate is 1900N/piece. Under the conditions of simulating the high-temperature zone environment in the blast furnace (temperature: 1100°C, atmosphere: CO:CO ₂ =4:1, gas flow rate: 1m/s), after 1 hour of reaction of 100g agglomerate sample, the reaction of this sample The crushing strength is 2900N/piece. Under the conditions of simulating the high temperature zone environment in the blast furnace (temperature: 1100°C, atmosphere: CO:CO ₂ =4:1, gas flow rate: 1m/s), after 1 hour of reaction of 100g agglomerate sample, the carbon gas of the sample The carbon gasification rate is 80%. As a comparison, under the same reaction conditions, the carbon gasification rate of ordinary coke with the same average particle size (composition shown in Table 4) is 8%.

Embodiment five (comparative example)

[1]. Preparation of ultra-fine iron ore powder: no iron ore powder is added.

[2]. Coal powder preparation: Table 2 shows the industrial analysis results of the bituminous coal used, and Table 3 shows the industrial analysis results of the anthracite used. Take 250g of the above-mentioned bituminous coal sample and 250g of the above-mentioned anthracite sample. After crushing, ball milling and mixing the two coal samples, the average particle size of the obtained mixed coal powder is 60 μm.

[3]. Mixing and briquetting of raw materials: the mixed material is pressed into agglomerates of Φ15mm×15mm, and the mass of each agglomerate is 5-6g. The binder adopts 2.0% waste paper pulp.

[4]. Drying of raw agglomerates: After natural drying of raw agglomerates for 24 hours, further drying at 200°C for 2 hours.

[5]. Roasting of raw agglomerates: using a tube furnace, roasting under the following conditions: the furnace temperature rises to 1000°C at a rate of 5°C/min; after holding at 1000°C for 30 minutes, it is naturally cooled to room temperature. During the _roasting process, N gas was fed into the furnace at a flow rate of 500ml/min. The carbon content of the agglomerates obtained was 91% by weight.

According to the national standard GB/T14201-93 test, its cold strength is 2200N/piece. Under the conditions of simulating the high temperature area in the blast furnace (temperature: 1100°C, atmosphere: CO:CO ₂ =4:1, gas flow rate: 1m/s), the 100g agglomerate sample reacts for 1 hour, and the sample is resistant to shattering after the reaction The strength is 300N/piece. Its mechanical strength cannot meet the requirements of blast furnace ironmaking.

Embodiment six (comparative example)

[1]. Preparation of ultra-fine iron ore powder: Table 2 shows the chemical analysis results of the iron ore concentrate used. Take 300g of iron ore concentrate sample, after the iron ore concentrate is crushed and fully ball milled, the average particle size of the obtained iron ore powder is 2.88 μm.

[2]. Coal powder preparation: Table 2 shows the industrial analysis results of the bituminous coal used, and Table 3 shows the industrial analysis results of the anthracite used. Take 150g of the above-mentioned bituminous coal sample and 150g of the above-mentioned non-coal sample. After primary crushing, ball milling and mixing, the average particle size of the mixed coal powder is 60μm.

[3]. Mixing and briquetting of raw materials: the mixed material is pressed into agglomerates with a diameter of Φ15mm×15mm. Each mass has a mass of 5-6 g. The binder adopts 2.0% waste paper pulp.

[4]. Drying of raw agglomerates: after natural drying of raw agglomerates for 24 hours, further drying at 200° C. for 1 hour.

[5]. Roasting of raw agglomerates: using a tube furnace, roasting under the following conditions: the furnace temperature rises to 1000°C at a rate of 5°C/min; after holding at 1000°C for 30 minutes, it is naturally cooled to room temperature. During the roasting process, N ₂ was fed into the furnace at a volume flow rate of 500 ml/min. The carbon content of the resulting agglomerate was 47 wt%.

Tested according to the national standard GB/T14201-93, the cold strength of the agglomerate sample is 500N/piece. Under the conditions of simulating the high-temperature zone environment in a blast furnace (temperature: 1100°C, atmosphere: CO:CO ₂ =4:1, gas flow rate: 1m/s), after 1 hour of reaction of 100g agglomerates, the post-reaction resistance of the sample The crushing strength is 300N/piece. Its strength cannot meet the requirements of blast furnace ironmaking.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications and substitutions can be made to these embodiments without departing from the principle and spirit of the present invention. and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (7)

1. a kind of blast furnace preparation method of high-carbonaceous metallized agglomerate, it is characterised in that：It the described method comprises the following steps：

Step 1: prepared by ultra-fine Iron Ore Powder：Iron ore is crushed and is fully finely ground into Iron Ore Powder with ball mill；

Step 2: pulverized coal preparation：Selected coal sample is prepared into coal dust；

Step 3: mixing and the briquetting of raw material：Ultra-fine Iron Ore Powder and coal dust are sufficiently mixed according to preset ratio, addition is certain Green briquette is suppressed after the organic binder and water of ratio, it is 300-400kg/cm to suppress pressure used in agglomerate², cold moudling obtains The moist mass of Φ (15-20) mm × 15-20mm；

Step 4: green briquette is dried：Green briquette obtained is fully dry；

Step 5: green briquette roasts：Agglomerate after drying is roasted under certain atmosphere and under certain temperature schedule.

2. the preparation method of the high-carbonaceous metallized agglomerate of blast furnace according to claim 1, it is characterised in that:The step 1 In, all iron content of the iron ore is more than 60wt%, and the average particle size of the ultra-fine Iron Ore Powder is 1-5 μm.

3. the preparation method of the high-carbonaceous metallized agglomerate of blast furnace according to claim 1, it is characterised in that:The step 2 In, the coal dust is weak cohesive bituminous coal and anthracitic mixture；The average particle size of the coal dust intermixture is 50-100 μm；Institute The fixation carbon content for stating coal dust intermixture is 65-75wt%, and volatile matter 18-25wt%, ash content is less than 10wt%.

4. the preparation method of the high-carbonaceous metallized agglomerate of blast furnace according to claim 1, it is characterised in that:Miberal powder and coal dust When being mixed, ranging from 1.5-2.0 of the miberal powder to the mass ratio of coal dust.

5. the preparation method of the high-carbonaceous metallized agglomerate of blast furnace according to claim 1, it is characterised in that:The step 3 In, the organic adhesive dosage during compacting agglomerate is no more than the 2% of mixture quality, and water content used is no more than 10%, organic binder is cellulose or secondary stock.

6. the preparation method of the high-carbonaceous metallized agglomerate of blast furnace according to claim 1, it is characterised in that:The step 4 In, green briquette drying temperature is 100-200 DEG C, drying time 1-2h.

7. the preparation method of the high-carbonaceous metallized agglomerate of blast furnace according to claim 1, it is characterised in that:The step 5 In, the atmosphere is N₂Atmosphere or isolation air；The temperature schedule be furnace temperature from room temperature with the heating rate of 5-10 DEG C/min It is raised to 900-1000 DEG C, after keeping the temperature 30-60min at a temperature of 900-1000 DEG C, naturally cools to room temperature.