Ferrocoke for blast furnace and preparation method thereof

Abstract

The invention provides a preparation method of iron coke for a blast furnace, which comprises the following steps: S1) crushing a coal sample with fluidity within 10000 ddpm, and humidifying to obtain a basic coal sample; s2) mixing the basic coal sample with an iron-based material to obtain a mixed coal sample; and S3) mixing the mixed coal sample and the inferior oil, and coking to obtain the iron coke for the blast furnace. The invention further provides the iron coke for the blast furnace. According to the iron coke for the blast furnace and the preparation method of the iron coke, the iron coke is prepared by mixing the basic coal sample, the iron-based material and the inferior oil, the quality of colloid in the coal coking process is improved, the quality of the iron coke is improved, and harmless treatment and recycling of inferior oil waste are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of iron and steel metallurgy, and in particular to iron coke for blast furnace and a preparation method thereof. Background Art

[0002] Currently, 90% of the world's iron production comes from blast furnace ironmaking; compared with existing non-blast furnace ironmaking technologies, blast furnace ironmaking has the characteristics of good technical and economic indicators, simple process, large production volume and low energy consumption. It is predicted that blast furnace ironmaking will still be the main iron production process for some time to come.

[0003] As a porous, brittle, carbon-rich composite material, ferrocoke contains transition metal iron, which can reduce the energy barrier for the formation of unstable activated complexes and promote the formation of carbon-oxygen complexes. At the same time, during the gasification process, it attracts CO in the carbon-oxygen complexes through the reduction of its own oxide, accelerates the oxygen exchange rate in the gasification reaction, and promotes the gasification reaction process. At the same time, iron, as the final product of blast furnace ironmaking, has no adverse effect on the smooth operation of the blast furnace. Therefore, ferrocoke has obvious advantages such as improving coke reactivity and reducing carbon emissions. However, at present, the post-reaction strength of ferrocoke is low, which is difficult to meet the needs of blast furnace ironmaking. Therefore, how to improve the strength of ferrocoke and produce ferrocoke that can meet the needs of blast furnace use is of great significance.

[0004] Various types of inferior oils in life, such as recycled cooking oil, repeatedly used frying oil, inferior oils processed from various animal meats and offal, and oily waste generated in cooking oil production, account for about 15% of the annual consumption of cooking oil, about 4 to 8 million tons. Inferior oil is of extremely poor quality and extremely unhygienic. Its peroxide value, acid value, heavy metals, microorganisms, etc. are seriously exceeded, and it contains toxins. If it flows into rivers, it will cause eutrophication of water bodies. Once consumed, it will damage human white blood cells and digestive tract mucosa, causing food poisoning and even cancer. At the same time, inferior oil contains light hydrocarbons, high concentrations of fatty acids, triglycerides, etc. Therefore, it is necessary to make resource utilization of inferior oil waste, so that it can be used as an additive to prepare iron coke with coal, increase the amount of colloids in the coal coking process, and realize the harmless treatment of waste. Summary of the invention

[0005] The technical problem solved by the present invention is to provide a ferrocoke for blast furnace. The ferrocoke provided by the present application can not only realize the recycling of inferior oil, but also improve the quality of the ferrocoke.

[0006] In view of this, the present application provides a method for preparing iron coke for blast furnace, comprising the following steps: S1) crushing the coal sample with fluidity within 10000 ddpm and adjusting the humidity to obtain a basic coal sample; S2) mixing the basic coal sample and the iron-based material to obtain a mixed coal sample; S3) mixing the mixed coal sample and the inferior oil and coking them to obtain iron coke for blast furnace.

[0007] Preferably, the basic coal samples include: coal sample A with a fluidity of 1000-2000 ddpm, coal sample B with a fluidity of 10-1000 ddpm, coal sample C with a fluidity of 2000-5000 ddpm, and coal sample D with a fluidity less than 10 ddpm.

[0008] Preferably, the preparation of the basic coal sample is specifically as follows: Coal sample A, coal sample B, coal sample C and coal sample D are crushed and then moistened respectively, and the moistened coal sample A, coal sample B, coal sample C and coal sample D are mixed to obtain a basic coal sample.

[0009] Preferably, based on the basic coal sample, the content of coal sample A after moisture adjustment is 20~35wt%, the content of coal sample B after moisture adjustment is 30~45wt%, the content of coal sample C after moisture adjustment is 10~20wt%, the content of coal sample D after moisture adjustment is 0~20wt%, and the iron-based material is 1~10wt% of the basic coal sample.

[0010] Preferably, the coal sample A is main coking coal, the coal sample B is 1 / 3 coking coal, the coal sample C is fat coal, and the coal sample D is lean coal; the iron-based material is selected from one or more of iron concentrate, vanadium-titanium magnetite and iron-containing waste.

[0011] Preferably, the moisture content of the base coal sample is 9-10%; the acid value of the inferior oil is 1000-110 mg (KOH) / g, and the peroxide value is 100-110 mmol / kg.

[0012] Preferably, based on the total amount of the mixed coal sample and the inferior oil, the content of the inferior oil is 1-10wt%; the bulk density of the mixture of the mixed coal sample and the inferior oil is 0.7-0.9t / m 3 .

[0013] Preferably, the fluidity of the mixture of the mixed coal sample and the inferior oil is 1000~2000ddpm.

[0014] Preferably, the coking process is specifically as follows: The mixed material is heated to 700-900°C at 8-12°C / min, and then heated to 1000-1050°C at 18-25°C / min. The coking time is 7-8h.

[0015] The applicant provides a blast furnace iron coke, which is prepared from a coal sample with a fluidity within 10000 ddmp, an iron-based material and low-quality oil.

[0016] The present application provides a method for preparing ferrocoke for blast furnaces, which comprises the following steps: firstly, crushing a coal sample with a fluidity of less than 10000 ddpm and then adjusting the humidity to obtain a basic coal sample; then mixing the basic coal sample with an iron-based material to obtain a mixed coal sample; and finally mixing the mixed coal sample with inferior oil and then coking to obtain ferrocoke for blast furnaces; in the process of preparing ferrocoke for blast furnaces, the basic coal sample and the iron-based material are used as the basis, and inferior oil is introduced, so that the iron in the iron-based material can catalyze the decomposition of some organic matter in the inferior oil, thereby promoting the conversion of the inferior oil into the main component of colloid; at the same time, the benzene, fatty acids and esters in the inferior oil are cracked at high temperature to become the main components of the colloid in the coal coking process, thereby increasing the amount of colloid in the ferrocoke in the coal coking process and improving the quality of the ferrocoke; at the same time, the inferior oil is reused as a ferrocoke additive to achieve harmless treatment of waste. DETAILED DESCRIPTION

[0017] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0018] In view of the demand for ferrocoke for blast furnaces in the prior art and the demand for harmless treatment and reuse of inferior oil, the present application provides a method for preparing ferrocoke for blast furnaces, which introduces coal samples, iron-based materials and inferior oil in the preparation process and cokes them, thereby obtaining ferrocoke, which can increase the amount of colloids in the coal coking process, improve the quality of ferrocoke, and achieve harmless treatment and reuse of inferior oil. Specifically, the embodiment of the present invention discloses a method for preparing ferrocoke for blast furnaces, comprising the following steps: S1) crushing the coal sample with fluidity within 10000 ddpm and adjusting the humidity to obtain a basic coal sample; S2) mixing the basic coal sample and the iron-based material to obtain a mixed coal sample; S3) mixing the mixed coal sample and the inferior oil and coking them to obtain iron coke for blast furnace.

[0019] In the preparation process of blast furnace iron coke, the present application first crushes and moistens the coal sample with a fluidity of less than 10000 ddpm to obtain a basic coal sample; in this process, the basic coal sample includes: coal type A with a fluidity of 1000-2000 ddpm, coal type B with a fluidity of 10-1000 ddpm, coal type C with a fluidity of 2000-5000 ddpm, and coal type D with a fluidity less than 10 ddpm; specifically, the fluidity of coal type A is 120 The fluidity of coal type A is 0~1800ddpm, the fluidity of coal type B is 20~800ddpm, the fluidity of coal type C is 2500~4600ddpm, and the fluidity of coal type D is 0~8ddpm; more specifically, the fluidity of coal type A is 1400~1750ddpm, the fluidity of coal type B is 240~710ddpm, the fluidity of coal type C is 3200~4100ddpm, and the fluidity of coal type D is 0~5ddpm. The fluidity is a side reflection of the colloid content in the coal type, which will affect the quality of iron coke.

[0020] In the present application, the coal types A, B, C and D can be selected from coal types well known to those skilled in the art according to the above-mentioned range of fluidity. For example, they can be independently selected from one or more of main coking coal, 1 / 3 coking coal, fat coal and lean coal. For example, the coal type A can be selected from main coking coal, the coal type B can be selected from 1 / 3 coking coal, the coal type C can be selected from fat coal, and the coal type D can be selected from lean coal. The main coking coal, the 1 / 3 coking coal, the fat coal and the lean coal are coal types well known to those skilled in the art, and the present application has no particular restrictions on their sources.

[0021] Furthermore, the preparation of the basic coal sample described in this application is specifically as follows: Coal type A, coal type B, coal type C and coal type D are crushed and humidified respectively, and the conditioned coal type A, coal type B, coal type C and coal type D are mixed to obtain a basic coal sample.

[0022] In the above-mentioned basic coal sample preparation process, the crushing is specifically carried out in a manner well known to those skilled in the art, and there is no particular limitation in this application. The moisture adjustment can be performed by directly adding water to the coal types A, B, C and D. The moisture content of the humidified coal type A is 9-10%, the moisture content of the humidified coal type B is 9-10%, the moisture content of the humidified coal type C is 9-10%, and the moisture content of the humidified coal type D is 9-10%.

[0023] The overlapping values ​​of the above fluidity, for example, 1000~2000ddpm specifically means greater than or equal to 1000ddpm and less than or equal to 2000ddpm, 10~1000ddpm specifically means greater than or equal to 10ddpm and less than 1000ddpm, and 2000~5000ddpm specifically means greater than 2000ddpm and less than or equal to 5000ddpm.

[0024] The present application then mixes the humidity-adjusted basic coal sample and the iron-based material to obtain a mixed coal sample; the mixing is a mixing method well known to those skilled in the art, and the present application does not impose any particular limitation on this. For example, the mixing is carried out in a mixer. Based on the basic coal sample, the content of the humidity-adjusted coal sample A is 20~35wt%, the content of the humidity-adjusted coal sample B is 30~45wt%, the content of the humidity-adjusted coal sample C is 10~20wt%, the content of the humidity-adjusted coal sample D is 0~20wt%, and the iron-based material is 1~10wt% of the basic coal sample; specifically, the content of the humidity-adjusted coal sample A is 22~33wt%, the content of the humidity-adjusted coal sample B is 32~43wt%, and the humidity-adjusted coal sample C is 10~20wt%. The content of coal sample C is 12-18wt%, the content of coal sample D after moisture adjustment is 2-15wt%, and the iron-based material is 3-8wt% of the basic coal sample; more specifically, the content of coal sample A after moisture adjustment is 25-30wt%, the content of coal sample B after moisture adjustment is 35-40wt%, the content of coal sample C after moisture adjustment is 13-16wt%, the content of coal sample D after moisture adjustment is 5-10wt%, and the iron-based material is 5-7wt% of the basic coal sample. In the present application, the iron-based material is selected from one or more of iron concentrate, vanadium-titanium magnetite and iron-containing waste; in a specific embodiment, the iron-based material is selected from vanadium-titanium iron concentrate; the iron concentrate, vanadium-titanium magnetite and iron-containing waste are materials well known to those skilled in the art, and their sources are not particularly limited in this application; in the present application, the TFe content in the iron-based material is ≥50% to ensure that the iron coke has sufficient reactivity.

[0025] Furthermore, the amount of coal type A with a fluidity of 1000-2000ddpm added after wetting is 20-35wt%, the amount of coal type B with a fluidity of 10-1000ddpm added after wetting is 30-45wt%, the amount of coal type C with a fluidity of 2000-5000ddpm added after wetting is 10-20wt%, and the amount of coal type D with a fluidity of less than 10ddpm added after wetting is 1-10%; specifically, the amount of coal type A with a fluidity of 1000-2000ddpm added after wetting is 22-33wt%, and the amount of coal type B with a fluidity of 10-1000ddpm added after wetting is 32-43wt%. wt%, the amount of coal type C with a fluidity of 2000~5000ddpm added after moistening is 12~18wt%, and the amount of coal type D with a fluidity of less than 10ddpm added after moistening is 2~15wt%; more specifically, the amount of coal type A with a fluidity of 1000~2000ddpm added after moistening is 25~30wt%, the amount of coal type B with a fluidity of 10~1000ddpm added after moistening is 35~40wt%, the amount of coal type C with a fluidity of 2000~5000ddpm added after moistening is 13~16wt%, and the amount of coal type D with a fluidity of less than 10ddpm added after moistening is 5~10wt%.

[0026] In the present application, as the content of the iron-based material increases, the reactivity of the iron coke increases, and the strength after the reaction decreases. The reduced strength makes it difficult for the iron coke to meet the requirements of blast furnace use. Therefore, the content of the iron-based material needs to be appropriate. Coal type A with a fluidity of 1000-2000 ddpm and coal type C with a fluidity of 2000-5000 ddpm are beneficial to the strength of the iron coke, among which A is the best and C is the second best.

[0027] Finally, the present application mixes the above-mentioned mixed coal sample and inferior oil and then cokes them to obtain iron coke for blast furnace; in this process, the inferior oil can be an inferior oil well known to those skilled in the art, and its acid value is 100~110mg (KOH) / g, and its peroxide value is 100~110mmol / kg. Specifically, the acid value of the inferior oil is 102~108mg (KOH) / g, and the peroxide value is 102~106mmol / kg. The acid value of the inferior oil can reflect the content of fatty acids in the inferior oil from the side, and fatty acids are components of the colloid of the bonding phase in the coal coking process. Therefore, the inferior oil with the above acid value is conducive to improving the quality of iron coke; the peroxide value is an indicator of the degree of oxidation of oils and fatty acids in the inferior oil, and the peroxide value within the above parameters can ensure the role of fatty acids in the coking process.

[0028] Based on the total mass of the mixed coal sample and the inferior oil, the content of the inferior oil is 1-10wt%, and the remainder is the mixed coal sample. Specifically, the content of the inferior oil is 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt% or 10wt%. If the content of the inferior oil is too high, it is easy to produce too much mobile phase, which is not conducive to the solidification in the later coal coking process, and thus not conducive to the strength of the coke. The bulk density of the mixed material of the mixed coal sample and the inferior oil is 0.7-0.9t / m 3 Specifically, the bulk density of the mixed coal sample and the inferior oil is 0.7 t / m 3 , 0.8t / m 3 or 0.9t / m 3 The fluidity of the mixture of the mixed coal sample and the inferior oil is 1000-2000 ddpm, and specifically, the fluidity of the mixture of the mixed coal sample and the inferior oil is 1200-1600 ddpm. In the present application, the coking is specifically: The mixed material is heated to 700-900°C at 8-12°C / min, and then heated to 1000-1050°C at 18-25°C / min. The coking time is 7-8h.

[0029] More specifically, the mixed material is heated to 700-800° C. at 9-10° C. / min, and then heated to 1050° C. at 20-23° C. / min, and the coking time is 7-8 hours.

[0030] The present application also provides an iron coke for blast furnace, which is prepared from a coal sample with a fluidity within 10000 ddmp, an iron-based material and low-quality oil.

[0031] The present application provides a blast furnace iron coke and a preparation method thereof, which utilizes inferior oil as the raw material of the iron coke, and achieves harmless treatment and reuse of the inferior oil while improving the quality of the iron coke.

[0032] In order to further understand the present invention, the preparation method of blast furnace iron coke provided by the present invention is described in detail below in conjunction with embodiments, and the protection scope of the present invention is not limited by the following embodiments. Example 1

[0033] Select coking coal, 1 / 3 coking coal, fat coal and lean coal with different fluidity (specific basic physical property analysis and thermoplastic characteristics are shown in Table 1), where the fluidity of coking coal is 1406ddpm, the fluidity of 1 / 3 coking coal is 248ddpm, the fluidity of fat coal is 4066ddpm, and the fluidity of lean coal is 0ddpm. The above coal samples are crushed respectively as basic coal samples; the above basic coal samples are humidified respectively to control the moisture content at 10%; The four kinds of basic coal samples after moisture adjustment and iron-based substances are mixed in a mixer, and the mixing ratio of the four kinds of coal samples is: main coking coal-30wt%, 1 / 3 coking coal-40wt%, fat coal-20wt%, lean coal-10wt%, and vanadium-titanium iron concentrate is 5% of the total weight of the above basic coal samples (based on the total weight of the basic coal samples, the main components of the vanadium-titanium iron concentrate are shown in Table 2), to obtain a mixed coal sample; Select inferior oil (main indicators are shown in Table 3) and mix it evenly with the mixed coal sample in a mixer. The fluidity of the obtained mixed material is 1218 ddpm. The amount of inferior oil added is 5wt%, and the rest is the mixed coal sample. Then put the mixed material into the coking reactor for tamping. First, raise the temperature of the coal sample to 800℃ at a heating rate of 10℃ / min, place the coking reactor in the center of the coke oven, and then raise the temperature to 1050℃ at a rate of 20℃ / min. Coking constant temperature time is 8h, then take out the coking reactor and cool it at room temperature to obtain iron coke for blast furnace. The bulk density of the mixed material in the coking reactor is 0.9t / m 3 The performance and structural indicators of the prepared ferrocoke are shown in Table 4.

[0034] Table 1 Basic physical properties and thermoplastic characteristics of coal samples Mad: air-dried basis moisture, Ad: air-dried basis; Vd: volatile matter, d: dry basis; Table 2 Main chemical composition data of vanadium-titanium iron concentrate / % TFe FeO <![CDATA[TiO 2 ]]> <![CDATA[V 2 THE 5 ]]> <![CDATA[SiO 2 ]]> <![CDATA[Al 2 THE 3 ]]> CaO 55.88 32.89 9.68 0.715 4.01 3.6 0.53 Table 3 Inferior oil index data table Acid value mg (KOH) / g Peroxide value mmol / kg 102 106 Table 4 Performance index data table of iron coke prepared in this example Reactivity / % Strength after reaction / % Crushing strength / % Wear resistance / % 33.27 60.45 89.23 4.17 As can be seen from Table 4, the post-reaction strength index of the coke prepared in this embodiment is better than the post-reaction strength of the first-class metallurgical coke by ≥60%, which meets the requirements of blast furnace production; and at the same time has the characteristics of high reactivity. Example 2

[0035] Select coking coal, 1 / 3 coking coal, fat coal and lean coal with different fluidity (specific basic physical property analysis and thermoplastic characteristics are shown in Table 1), where the fluidity of coking coal is 1406ddpm, the fluidity of 1 / 3 coking coal is 248ddpm, the fluidity of fat coal is 4066ddpm, and the fluidity of lean coal is 0ddpm. The above coal samples are crushed respectively as basic coal samples; the above basic coal samples are humidified respectively to control the moisture content at 10%; The four kinds of basic coal samples after moisture adjustment and iron-based substances are mixed in a mixer, and the mixing ratio of the four kinds of coal samples is: main coking coal-30wt%, 1 / 3 coking coal-40wt%, fat coal-20wt%, lean coal-10wt%, and vanadium-titanium iron concentrate is 5% of the total weight of the above basic coal samples (based on the total weight of the basic coal samples, the main components of the vanadium-titanium iron concentrate are shown in Table 2), to obtain a mixed coal sample; Select inferior oil (main indicators are shown in Table 3) and mix the mixed coal sample in a mixer to mix evenly. The fluidity of the obtained mixed material is 1564 ddpm. The amount of inferior oil added is 10wt%, and the rest is the mixed coal sample. Then put the mixed material into the coking reactor for tamping. First, raise the temperature of the coal sample to 800℃ at a heating rate of 10℃ / min, place the coking reactor in the center of the coke oven, and then raise the temperature to 1050℃ at a rate of 20℃ / min. Coking constant temperature time is 8h, then take out the coking reactor and cool it at room temperature to obtain iron coke for blast furnace. The bulk density of the mixed material in the coking reactor is 0.9t / m 3 The performance and structural indicators of the prepared iron coke are shown in Table 5; Table 5 Performance and structural index data table of iron coke Reactivity / % Strength after reaction / % Crushing strength / % Wear resistance / % 33.24 65.78 90.12 3.54 It can be seen from Table 5 that the post-reaction strength index of the coke prepared in this embodiment is better than the post-reaction strength of the first-class metallurgical coke by ≥60%, which meets the requirements of blast furnace production; and at the same time has the characteristics of high reactivity.

[0036] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0037] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing blast furnace iron coke, comprising the following steps: S1) crushing the coal sample with fluidity within 10000 ddpm and adjusting the humidity to obtain a basic coal sample; S2) mixing the basic coal sample and the iron-based material to obtain a mixed coal sample; S3) The mixed coal sample and the inferior oil are mixed and coked to obtain iron coke for blast furnace.

2. The preparation method according to claim 1, characterized in that: The basic coal samples include: coal sample A with a fluidity of 1000-2000 ddpm, coal sample B with a fluidity of 10-1000 ddpm, coal sample C with a fluidity of 2000-5000 ddpm, and coal sample D with a fluidity less than 10 ddpm.

3. The preparation method according to claim 1, characterized in that: The preparation of the basic coal sample is specifically as follows: Coal sample A, coal sample B, coal sample C and coal sample D are crushed and then moistened respectively, and the moistened coal sample A, coal sample B, coal sample C and coal sample D are mixed to obtain a basic coal sample.

4. The preparation method according to claim 2 or 3, characterized in that: Based on the basic coal sample, the content of the wetted coal sample A is 20~35wt%, the content of the wetted coal sample B is 30~45wt%, the content of the wetted coal sample C is 10~20wt%, the content of the wetted coal sample D is 0~20wt%, and the iron-based material is 1~10wt% of the basic coal sample.

5. The preparation method according to claim 2 or 3, characterized in that: The coal sample A is main coking coal, the coal sample B is 1 / 3 coking coal, the coal sample C is fat coal, and the coal sample D is lean coal; the iron-based material is selected from one or more of iron concentrate, vanadium-titanium magnetite and iron-containing waste.

6. The preparation method according to claim 4, characterized in that: The moisture content of the basic coal sample is 9~10%; the acid value of the inferior oil is 1000~110mg (KOH) / g, and the peroxide value is 100~110mmol / kg.

7. The preparation method according to claim 1, characterized in that: Based on the total amount of the mixed coal sample and the inferior oil, the content of the inferior oil is 1-10wt%; the bulk density of the mixed material of the mixed coal sample and the inferior oil is 0.7-0.9t / m 3 .

8. The preparation method according to claim 1, characterized in that: The fluidity of the mixture of the mixed coal sample and the inferior oil is 1000-2000 ddpm.

9. The preparation method according to claim 1, characterized in that: The coking process is specifically as follows: The mixed material is heated to 700-900°C at 8-12°C / min, and then heated to 1000-1050°C at 18-25°C / min. The coking time is 7-8h.

10. A blast furnace iron coke prepared from a coal sample with a fluidity of less than 10,000 ddmp, an iron-based material and low-quality oil.