A coke enhancing modifier and its preparation method and coke modification method

Abstract

The present invention provides a coke strengthening and modifier, its preparation method, and a coke modification method, belonging to the field of blast furnace ironmaking technology. The coke strengthening and modifier provided by the present invention comprises the following raw material components: 15-30 parts boric anhydride; 10-14 parts solid water glass; 3-5 parts mineralizer; 5-8 parts film-forming agent; and 2-8 parts surface wetting agent. The mineralizer is a mixture of yttrium nitrate and cerium chloride in a 1:1 weight ratio. The coke strengthening and modifier provided by the present invention can form a coating on the coke surface, improving the toughness and strength of the coke, and slowing the dissolution reaction of the coke, thereby reducing the cost of existing blast furnace ironmaking. The coke strengthening and modifier has a wide range of raw material sources, a simple preparation process, and low cost. It is simple to use, requires a small amount, and has excellent modification effects. It can significantly reduce the reactivity of the coke and significantly increase the post-reaction strength of the coke. The method of the present invention can reduce the coke ratio, increase pig iron production, and reduce carbon emissions.

Description

Technical Field

[0001] The invention belongs to the technical field of blast furnace ironmaking, and particularly relates to a coke enhancing modifier, a preparation method thereof, and a coke modification method. Background Art

[0002] The steel industry is a high-energy-consuming and high-emission industry. Reducing the consumption of raw materials such as fossil energy and energy consumption in the production process through new materials and new processes has always been the goal pursued by enterprises.

[0003] Modern blast furnaces utilize technologies such as high air temperature, high air volume, oxygen enrichment, and a high coal ratio to achieve the goal of enhanced blast furnace smelting. Coke is an important metallurgical raw material. Its main functions in blast furnace ironmaking are as follows: (1) supporting the charge within the furnace, acting as a skeleton to ensure the charge's air permeability; (2) providing smelting energy through the exothermic reaction between combustion and oxygen; (3) acting as a reducing agent and carburizing agent for iron ore; and (4) filling and activating the hearth, providing a greater spatial coefficient for the hearth. Therefore, blast furnace ironmaking places high demands on coke collection.

[0004] Blast furnace ironmaking generally has the following requirements for coke: (1) It has high strength and is not easy to break. It can withstand the impact, extrusion, and wear of the coke from entering the furnace to the furnace hearth, which may reduce the particle size; (2) It has good resistance to dissolution. The dissolution of coke in high temperature areas, alkali metal corrosion, slag iron dissolution, and dissolution into molten iron should be as slow as possible; (3) The particle size range is narrow, which can ensure good air permeability.

[0005] However, the partial replacement of coke by pulverized coal weakens its role as a fuel, reducing agent, and carburizing agent in the blast furnace, while enhancing its role as a loosening skeleton, affecting the coke's thermal properties. This significantly prolongs the coke's residence time within the furnace and significantly increases its melt loss, leading to a decrease in its thermal strength and limiting further enhancements to blast furnace production. Therefore, reducing coke reactivity and increasing its post-reaction strength have become key to strengthening blast furnace production, reducing the coke ratio, and lowering ironmaking costs.

[0006] Among the existing methods, the common ways to reduce the coke ratio are to increase the smelting intensity, increase the wind temperature, increase the ore grade and improve the coke quality. However, these methods often have the problem of high costs and cannot be effectively applied to production operations.

[0007] Recent research has shown that the use of coke passivators can reduce coke reactivity and improve its post-reaction strength. For example, Cui Ping, Yang Min, and others used an immersion method to load H₃BO₃, Na₂CO₃, CaCl₂, and FeCl₃ into coke. Their results showed that minerals of varying concentrations could be incorporated into the coke through immersion, with the final form of boron being B₂O₃. The presence of alkali and iron can accelerate the dissolution reaction of the coke, while the presence of boron can inhibit the dissolution reaction and provide significant resistance or shielding against alkali and iron corrosion. Furthermore, the application of passivated coke in blast furnaces at Jigang has demonstrated that water quenching with a passivating agent significantly reduces the gasification reactivity of the coke and improves its post-reaction strength. Furthermore, Baotou Steel has conducted experimental studies on coke passivation, demonstrating that using boric acid water to simulate industrial coke quenching also significantly improves the thermal reactivity and post-reaction strength of the coke.

[0008] These studies indicate that the use of coke modification or coke passivation agents can, to a certain extent, reduce the thermal reactivity of coke in blast furnace ironmaking and improve its post-reaction strength. However, these methods increase the production cost of the coking process and extend the investment cycle, thus affecting the overall economic benefits of the enterprise and contributing to the high cost of ironmaking.

[0009] Existing companies and scholars have also conducted a large amount of related research on patent methods. For example, patent CN 1321168 C discloses a coke modification method, which uses a mixture of titanium dioxide, boron oxide, and boric acid as a solute and sprays it on the coke surface to achieve the purpose of reducing the reactivity of the coke and increasing the strength after the reaction. For another example, patent CN101082008 B discloses a coke passivator containing lanthanide rare earth elements and its use method, which is to grind 1-30wt% borax, 1-20wt% wollastonite, and 0.01-5wt% lanthanide rare earth chloride salt, mix them with 60-90wt% boric acid, and add 0.01-2wt% carboxymethyl cellulose after mixing to prepare a coke passivator solution containing lanthanide rare earth elements. For example, patent CN107142121 B discloses a coke modifier and a coke modification method. The coke modifier is composed of 7 parts of boron oxide, 2 parts of sodium silicate and 1 part of polyacrylamide. The coke modifier is prepared into a coke modifier solution with a mass concentration of 4.0-7.0%, and then the coke modifier solution is sprayed before the coke is put into the furnace, thereby reducing the reactivity of the coke, increasing the strength after the reaction, and improving the permeability of the blast furnace.

[0010] Although the above patented method can reduce production costs to a certain extent, and the operation method only requires spraying the coke passivator on the coke, the coke modifier required by the above method is high in concentration and dosage, and the modification cost is relatively high. In addition, the effect of the modifier on reducing the reactivity of the coke and improving the post-reaction strength of the coke is not very significant, and still needs to be further improved.

[0011] Therefore, how to provide a coke enhancing modifier with convenient raw material source, low cost, simple preparation process, small amount of modifier and good modification effect has become a technical problem to be solved urgently. Summary of the Invention

[0012] The present invention is intended to address the above-mentioned technical problems, thereby providing a coke enhancing modifier, a preparation method thereof, and a coke modification method. The technical objectives of the present invention are, on the one hand, to address the problem that existing coke passivators have poor modification effects and are insufficient in reducing the reactivity of coke and improving the strength of coke after reaction; and, on the other hand, to address the problem that existing coke passivators or modifiers require high concentrations and large dosages, resulting in high modification costs.

[0013] In order to achieve the above technical objectives, the technical solutions adopted by the present invention are as follows:

[0014] The present invention first provides a coke enhancing and modifying agent, which comprises the following raw material components in parts by weight:

[0015] 15-30 parts of boric anhydride;

[0016] 10-14 parts of solid water glass;

[0017] 3-5 parts of mineralizer;

[0018] 5-8 parts of film-forming agent;

[0019] 2 to 8 parts of surface wetting agent;

[0020] Wherein, the mineralizer is a mixture of yttrium nitrate and cerium chloride in a weight ratio of 1:1.

[0021] Since the flaky cleavage structure of coke itself determines its easy breakage under the action of external force, the dissolution reaction in the soft melting zone is violent. The coke strengthening modifier of the present invention can form a coating layer on the surface of coke, which can not only improve the toughness and strength of coke, but also delay the dissolution reaction of coke. It is of great significance to improve the stability of blast furnace ironmaking process, reduce coke ratio, reduce emissions and improve economic benefits.

[0022] The coke-enhancing modifier of the present invention has an abundant raw material source, a simple preparation method, and low cost. When used in blast furnace ironmaking, the coke-enhancing modifier not only improves coke strength and reduces coke dissolution loss, but also reduces the coke ratio at a low cost. The coke-enhancing modifier of the present invention significantly reduces the reactivity of coke and significantly increases the post-reaction strength of coke.

[0023] On the other hand, the coke enhancing modifier of the present invention also has the advantages of low usage concentration, small usage amount and good modification effect, which can further reduce the investment cost of the modifier.

[0024] The use of other existing coke passivators or modifiers cannot achieve the technical effects of the present invention. In addition, the modification effect of the coke modifiers not included in the formulation of the present invention will be significantly reduced.

[0025] Furthermore, the coke enhancing modifier comprises the following raw material components in parts by weight:

[0026] 20 parts of boric anhydride;

[0027] 12 parts of solid water glass;

[0028] 4 parts of mineralizer;

[0029] 6 parts of film-forming agent;

[0030] 5 parts of surface wetting agent.

[0031] Furthermore, the film-forming agent includes hydroxypropyl cellulose or carboxymethyl cellulose.

[0032] Furthermore, the surface wetting agent includes sodium butylnaphthalenesulfonate.

[0033] Furthermore, the modulus of the solid water glass is 1.5 to 2.5.

[0034] Furthermore, the purity of the boric anhydride is above 98%.

[0035] A second object of the present invention is to provide a method for preparing the coke enhancing modifier as described above, comprising the following steps:

[0036] (1) Weigh the corresponding raw materials by weight and mix them;

[0037] (2) adding the mixed raw material obtained in step (1) into water and stirring uniformly to obtain a coke enhancing modifier with a mass concentration of 1 to 2%.

[0038] A third object of the present invention is to provide a coke modification method comprising the following steps:

[0039] (1) preparing a coke enhancing modifier solution;

[0040] (2) Spray the coke enhancing and modifying agent solution obtained in step (1) on the surface of the coke before the coke is put into the furnace.

[0041] Furthermore, the amount of the coke enhancing modifier solution in step (2) is 1 to 2% of the weight of the coke.

[0042] Furthermore, in step (2), the coke enhancing and modifying agent solution is sprayed onto the coke surface by a pressurizing device or a spraying device.

[0043] The beneficial effects of the present invention are as follows:

[0044] (1) The present invention provides a coke enhancing modifier, which has a wide source of raw materials, a simple preparation process and low cost;

[0045] (2) The coke enhancing modifier provided by the present invention has a low concentration, a small amount, a good modification effect, can significantly reduce the reactivity of coke, and greatly improve the post-reaction strength of coke;

[0046] (3) The coke strengthening and modifier provided by the present invention can form a coating layer on the surface of coke, which can improve the toughness and strength of coke, and can delay the dissolution reaction of coke, thereby reducing the cost of existing blast furnace ironmaking. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is described in detail below with reference to the following embodiments. It is necessary to point out that the following embodiments are only used to explain and illustrate the present invention and are not intended to limit the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above invention content still fall within the scope of protection of the present invention.

[0048] Example 1

[0049] A coke enhancing and modifying agent, comprising the following raw material components in parts by weight:

[0050] 15 parts of boric anhydride;

[0051] 10 parts of solid water glass;

[0052] 3 parts of mineralizer;

[0053] 5 parts of film-forming agent;

[0054] 2 parts of surface wetting agent;

[0055] The mineralizer is a mixture of yttrium nitrate and cerium chloride in a weight ratio of 1:1. The film-forming agent is hydroxypropyl cellulose or carboxymethyl cellulose. The surface wetting agent is sodium butyl naphthalene sulfonate. The modulus of the solid water glass is 1.5 to 2.5. The purity of the boric anhydride is 98%.

[0056] The preparation method of the above-mentioned coke enhancing modifier comprises the following steps:

[0057] (1) Weigh the corresponding raw materials by weight and mix them;

[0058] (2) Add the mixed raw material obtained in step (1) into water and stir evenly to obtain a coke enhancing modifier with a mass concentration of 1%.

[0059] Example 2

[0060] A coke enhancing and modifying agent, comprising the following raw material components in parts by weight:

[0061] 30 parts of boric anhydride;

[0062] 14 parts of solid water glass;

[0063] 5 parts of mineralizer;

[0064] 8 parts of film-forming agent;

[0065] 8 parts of surface wetting agent;

[0066] The mineralizer is a mixture of yttrium nitrate and cerium chloride in a weight ratio of 1:1. The film-forming agent is hydroxypropyl cellulose or carboxymethyl cellulose. The surface wetting agent is sodium butyl naphthalene sulfonate. The modulus of the solid water glass is 1.5 to 2.5. The purity of the boric anhydride is 98%.

[0067] The preparation method of the above-mentioned coke enhancing modifier comprises the following steps:

[0068] (1) Weigh the corresponding raw materials by weight and mix them;

[0069] (2) Add the mixed raw material obtained in step (1) into water and stir evenly to obtain a coke enhancing modifier with a mass concentration of 1%.

[0070] Example 3

[0071] A coke enhancing and modifying agent, comprising the following raw material components in parts by weight:

[0072] 20 parts of boric anhydride;

[0073] 12 parts of solid water glass;

[0074] 4 parts of mineralizer;

[0075] 6 parts of film-forming agent;

[0076] 5 parts of surface wetting agent.

[0077] The mineralizer is a mixture of yttrium nitrate and cerium chloride in a weight ratio of 1:1. The film-forming agent is hydroxypropyl cellulose or carboxymethyl cellulose. The surface wetting agent is sodium butyl naphthalene sulfonate. The modulus of the solid water glass is 1.5 to 2.5. The purity of the boric anhydride is 98%.

[0078] The preparation method of the above-mentioned coke enhancing modifier comprises the following steps:

[0079] (1) Weigh the corresponding raw materials by weight and mix them;

[0080] (2) Add the mixed raw material obtained in step (1) into water and stir evenly to obtain a coke enhancing modifier with a mass concentration of 1%.

[0081] Comparative Example 1

[0082] Compared with the coke passivator containing lanthanide rare earth elements in patent CN 101082008 B, the coke passivator is added at 3wt% of the coke mass, its reactivity can be reduced to 19.57%, and the strength after thermal reaction can be increased to 75.62%.

[0083] Comparative Example 2

[0084] Compared with the coke passivator containing trace additives in patent CN 102041129 B, the coke passivator is added at 5wt% of the coke mass, its reactivity can be reduced to 18.72%, and the strength after thermal reaction can be increased to 77.64%.

[0085] Comparative Example 3

[0086] Compared with the coke modifier in patent CN 107142121 B, the concentration of the coke modifier solution is 7wt%. When 30kg of coke modifier is sprayed per ton of coke, its reactivity can be reduced to 18.30% and the strength after thermal reaction can be increased to 71.29%.

[0087] Comparative Example 4

[0088] The method of Example 1 is followed, except that only yttrium nitrate is used as the mineralizer.

[0089] Comparative Example 5

[0090] The method of Example 2 is followed, except that only cerium chloride is used as the mineralizer.

[0091] Comparative Example 6

[0092] The method of Example 3 is followed, except that the mineralizer is a mixture of lanthanum nitrate and cerium chloride in a weight ratio of 1:1.

[0093] Comparative Example 7

[0094] The method of Example 3 is followed, except that the mineralizer is a mixture of yttrium nitrate and cerium chloride in a weight ratio of 2:1.

[0095] Comparative Example 8

[0096] The method of Example 3 is followed, except that the mineralizer is a mixture of yttrium nitrate and cerium chloride in a weight ratio of 1:2.

[0097] Comparative Example 9

[0098] The method of Example 3 is followed, except that the mineralizer is a mixture of yttrium nitrate and cerium chloride in a weight ratio of 1.5:1.

[0099] Comparative Example 10

[0100] The method of Example 3 is followed, except that the mineralizer is a mixture of yttrium nitrate and cerium chloride in a weight ratio of 1:1.5.

[0101] Comparative Example 11

[0102] The method of Example 3 is followed, except that boric anhydride is replaced by borax.

[0103] Experimental Example 1

[0104] The coke enhancing modifiers obtained in the above examples and comparative examples were respectively used for coke modification. The modification method was as follows: the prepared coke enhancing modifier solution was sprayed on the surface of coke (10 kg) before the coke was put into the furnace, and the amount of the coke enhancing modifier solution (0.2 kg) was fixed at 1% of the weight of the coke. During the spraying, a pressure pump and a nozzle were used to perform a three-dimensional cross-spraying and atomized spraying to spray the coke enhancing modifier solution on the surface of the coke.

[0105] The thermal reactivity and post-reaction strength of coke were measured according to the standard "GB / T 4000-2017 Test method for reactivity and post-reaction strength of coke". The results are shown in Table 1 below.

[0106] Table 1

[0107]

[0108]

[0109] The experimental results in Table 1 above demonstrate that the coke-enhancing and modifier prepared in the Examples of the present invention exhibits excellent coke modification effects and excellent thermal performance enhancement, reducing coke reactivity to 11.35% and increasing post-reaction strength to 85.10%. Furthermore, the coke-enhancing and modifier of the present invention achieves excellent results with minimal usage and low concentration.

[0110] However, when the coke modifiers in other comparative examples or prior art are used and the concentration and dosage are reduced, the modification effect on the coke is poor and the effect of the present invention cannot be achieved.

[0111] Tests have shown that the coke-enhancing modifier of the present invention effectively inhibits coke pulverization within the furnace, enhances its skeletal support, improves blast furnace permeability, reduces blast furnace overburden, lowers slag viscosity, and increases molten iron fluidity. The modified coke reduces the coke ratio by 10-15 kg / t iron in the blast furnace reaction, and increases pig iron production by 5-8%.

[0112] By adopting the method of the present invention, compared with the unmodified coke, the coke consumption is reduced by 8-13 kg per ton of pig iron. Assuming the coke price is 2500 yuan / ton, the coke procurement cost per ton of pig iron is reduced by 20-32.5 yuan. After deducting the procurement cost of the coke enhancement modifier of 12 yuan / ton, the cost per ton of iron is reduced by 12-22.5 yuan.

[0113] By adopting the method of the present invention, the amount of coke can be reduced by 8-13 kg per ton of pig iron, and carbon dioxide emissions can be reduced by 19.9-32.37 kg, bringing in carbon sequestration income of 0.5-0.81 yuan.

[0114] Based on the production of 100 million tons of pig iron, the coke enhancement modifier of the present invention can reduce the cost of iron per ton for enterprises by 1.2-2.25 billion yuan and generate carbon sequestration income of 50-81 million yuan, and at the same time play a positive role in the realization of my country's grand goals.

Claims

1. A coke enhancing modifier, characterized in that: The coke enhancing modifier comprises the following raw material components in parts by weight: 15-30 parts of boric anhydride; 10-14 parts of solid water glass; 3-5 parts of mineralizer; 5-8 parts of film-forming agent; 2 to 8 parts of surface wetting agent; Wherein, the mineralizer is a mixture of yttrium nitrate and cerium chloride in a weight ratio of 1:

1.

2. The coke enhancing and modifying agent according to claim 1, characterized in that The coke enhancing modifier comprises the following raw material components in parts by weight: 20 parts of boric anhydride; 12 parts of solid water glass; 4 parts of mineralizer; 6 parts of film-forming agent; 5 parts of surface wetting agent.

3. The coke enhancing and modifying agent according to claim 1 or 2, characterized in that The film-forming agent includes hydroxypropyl cellulose or carboxymethyl cellulose.

4. The coke enhancing and modifying agent according to claim 1 or 2, characterized in that The surface wetting agent includes sodium butylnaphthalenesulfonate.

5. The coke enhancing and modifying agent according to claim 1 or 2, characterized in that: The modulus of the solid water glass is 1.5 to 2.

5.

6. The coke enhancing modifier according to claim 1 or 2, characterized in that: The purity of the boric anhydride is above 98%.

7. A method for preparing the coke enhancing and modifying agent according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Weigh the corresponding raw materials by weight and mix them; (2) adding the mixed raw material obtained in step (1) into water and stirring uniformly to obtain a coke enhancing modifier with a mass concentration of 1 to 2%.

8. A coke modification method, characterized in that: The following steps are involved: (1) preparing a coke enhancing modifier solution according to the method of claim 7; (2) Spray the coke enhancing and modifying agent solution obtained in step (1) on the surface of the coke before the coke is put into the furnace.

9. The coke modification method according to claim 8, characterized in that The amount of the coke enhancing and modifying agent solution in step (2) is 1 to 2% of the weight of the coke.

10. The coke modification method according to claim 8 or 9, characterized in that: In step (2), the coke enhancing and modifying agent solution is sprayed onto the coke surface through a pressurizing device or a spraying device.

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