Graphitized carburant and preparation method thereof

Abstract

The invention provides a graphitized carburant and a preparation method thereof, and relates to the technical field of carburant preparation. The graphitization carburant is prepared from pretreated petroleum coke, purified graphite electrode waste, wood charcoal, carboxymethyl cellulose sodium and modified starch, wherein the pretreated petroleum coke is obtained by soaking petroleum coke in alkali liquor, cleaning with ethanol, drying, filling oxygen under the pressure of 3-5 Mpa for high-pressure treatment and calcining; the modified starch is obtained by gelatinizing cassava starch, performing microwave shaping and crushing. According to the method, the defects in the prior art are overcome, the purity of the carburant can be effectively guaranteed, meanwhile, the recarburization effect of the carburant is further improved, and the economic benefit of overall production is improved.

Description

Technical Field

[0001] This invention relates to the field of carbon raiser preparation technology, specifically to a graphitized carbon raiser and its preparation method. Background Technology

[0002] Graphitized carbon raisers are carbon-containing materials with graphite as the main component, whose molecular structure is changed through high-temperature graphitization treatment. They are characterized by high purity, high crystallinity, and low sulfur and nitrogen content, and are widely used in steel smelting, casting and other fields to effectively improve steel performance and reduce production costs.

[0003] Currently, the main raw materials for graphitized recarburizers include petroleum coke, pitch coke, biomass raw materials, and graphite waste. Generally, the raw materials are graphitized and then bonded and pressed into shape, which reduces the overall carbon content. Due to differences in raw material composition and mixing methods, the uniformity of pores also varies, which has a certain impact on the carbon absorption rate of the final product smelting. Therefore, ensuring the purity of graphitized recarburizers and improving their performance is a major research direction at present. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a graphitized recarburizing agent and its preparation method, which can effectively ensure the purity of the recarburizing agent, while further improving the recarburizing effect of the recarburizing agent and enhancing the overall economic benefits of production.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A graphitized recarburizing agent, wherein the graphitized recarburizing agent is prepared from the following raw materials in parts by weight: 15-20 parts of pretreated petroleum coke, 10-20 parts of purified graphite electrode waste, 8-10 parts of wood charcoal, 2-4 parts of sodium hydroxymethyl cellulose, and 3-5 parts of modified starch; wherein the pretreated petroleum coke is obtained by soaking petroleum coke in alkaline solution, washing it with ethanol, drying it, and then subjecting it to high-pressure treatment under oxygen at a pressure of 3-5 MPa, followed by calcination; wherein the modified starch is obtained by gelatinizing cassava starch, microwaving it, and then pulverizing it.

[0006] Preferably, the specific preparation method of the pretreated petroleum coke includes the following steps: S1-1. Place the petroleum coke in an aqueous sodium hydroxide solution with a pH of 9.5-10 and stir at 45-60℃ for 30-50 minutes. Then remove it and rinse it with ethanol until neutral to obtain alkaline-treated petroleum coke. S1-2. Place the alkali-treated petroleum coke under a pressure of 3-5 MPa and introduce oxygen. React for 20-30 minutes, then remove it to obtain high-pressure oxidized petroleum coke for later use. S1-3. The high-pressure oxidized petroleum coke is calcined at 1200-1500℃ for 1-2 hours under a nitrogen atmosphere, and then crushed to a particle size of 10-20mm to obtain pretreated petroleum coke.

[0007] Preferably, the method for preparing the modified starch includes the following steps: S2-1. Add 5 times the volume of water to the cassava starch and stir evenly. Then, stir and sulfonate the starch in a water bath at 60-65℃ for 30-40 minutes. After that, dry it at 45℃ until the moisture content is ≤20% to obtain the gelatinized starch material for later use. S2-2. Place the above gelatinized starch material in a microwave oven and microwave it at 280W until it reaches a constant weight to obtain modified starch.

[0008] Preferably, the preparation of the purified graphite electrode waste is as follows: the graphite electrode waste is ground into a slurry with water, the pH is adjusted to 4-5 with sulfuric acid, soaked and rinsed with clean water, then placed in an alkaline solution with a pH of 10-11 and stirred, then rinsed with clean water and dried to obtain the final product.

[0009] The preparation method of graphitized recarburizing agent includes the following steps: (1) Mix and grind the pretreated petroleum coke, purified graphite electrode waste and wood carbon, and then heat to 2000-2500℃ for graphitization treatment for 1.5-2 hours to obtain graphitized raw materials for later use. (2) Mix the above graphitized raw materials with sodium hydroxymethyl cellulose and modified starch, then add 2 times the volume of water and stir thoroughly to obtain a mixture for later use. (3) Place the above mixture in a sintering furnace and sinter it at 200-300℃. Take it out and crush it initially. Then raise the temperature to 400-500℃ and continue sintering. Take it out and cool it down. Then continue to crush it to control the particle size to 0.2-2mm to obtain graphitized carbon raiser.

[0010] Preferably, in step (1), the grinding and pulverizing process passes through an 80-mesh sieve.

[0011] Preferably, in step (2), the stirring speed for thorough mixing is 800-1000 r / min, and the stirring time is 15-20 min.

[0012] Preferably, the initial sintering time in step (3) is 50-80 min, and the sintering time is 60-90 min.

[0013] This invention provides a graphitized recarburizing agent and its preparation method, which has the following advantages compared with the prior art: This invention uses pretreated petroleum coke, graphite electrode waste, and charcoal as main raw materials to produce a graphitized recarburizing agent. The utilization efficiency of the petroleum coke is improved through alkaline leaching, high-pressure oxygen treatment, and calcination, further reducing the impurity content in the recarburizing agent and enhancing its recarburizing effect. Simultaneously, sodium hydroxymethyl cellulose and modified starch are used to mix the raw materials, promoting uniformity in mixing. Subsequent two sintering processes remove impurities from the sodium hydroxymethyl cellulose and modified starch while retaining their carbon content, ensuring uniform pore size in the product and comprehensively improving the overall effectiveness of the recarburizing agent. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] Example 1: Preparation of graphite recarburizer: 1. Preparation of raw materials: 1.1 Preparation of pretreated petroleum coke: (1) Place the petroleum coke in an aqueous sodium hydroxide solution with a pH of 10, stir at 50°C for 40 min, then remove and rinse with ethanol until neutral to obtain alkaline-treated petroleum coke. (2) The alkali-treated petroleum coke was placed under a pressure of 4 MPa and oxygen was introduced. After reacting for 25 minutes, it was taken out to obtain high-pressure oxidized petroleum coke for later use. (3) The high-pressure oxidized petroleum coke was calcined at 1400℃ for 1.5h under nitrogen atmosphere and then crushed to a particle size of 10-20mm to obtain pretreated petroleum coke.

[0016] 1.2 Preparation of calcined petroleum coke: (1) Place the petroleum coke in an aqueous sodium hydroxide solution with a pH of 10, stir at 50°C for 40 min, then remove and rinse with ethanol until neutral to obtain alkaline-treated petroleum coke. (2) The alkali-treated petroleum coke was calcined at 1400℃ for 1.5h under a nitrogen atmosphere and then crushed to a particle size of 10-20mm to obtain calcined petroleum coke.

[0017] 1.3 Obtaining modified starch: (1) Select cassava starch. Add 5 times the volume of water to the cassava starch and stir evenly. Then stir and sulfonate at 65°C water bath temperature for 35 minutes. Then dry at 45°C until the moisture content is ≤20% to obtain gelatinized starch material for later use. (2) Place the above gelatinized starch material in a microwave oven and microwave it at 280W until it reaches a constant weight to obtain modified starch.

[0018] 1.4. Coconut shell biochar is selected for wood charcoal.

[0019] 1.5 Preparation of purified graphite electrode waste: (1) Grind the graphite electrode waste with 5 times the volume of water into a slurry, then add sulfuric acid to adjust the pH to 4, soak for 2 hours, and then rinse with water until neutral to obtain acid-treated graphite electrode waste. (2) The above-obtained acid-treated graphite electrode waste was placed in a potassium hydroxide solution with a pH of 10 and soaked for 1 hour. After rinsing with clean water, it was dried at 55°C to obtain purified graphite electrode waste.

[0020] 2. Preparation of graphitized recarburizing agent: (1) Prepare materials according to the following weight parts: 18 parts petroleum coke, 15 parts purified graphite electrode waste, 9 parts wood charcoal, 3 parts sodium hydroxymethyl cellulose, and 4 parts starch. (2) Petroleum coke, purified graphite electrode waste and wood charcoal are mixed, ground and crushed and passed through an 80-mesh sieve. Then the temperature is raised to 2400℃ for graphitization treatment for 2 hours to obtain graphitized raw materials for use. (3) Mix the above graphitized raw materials with sodium hydroxymethyl cellulose and starch, then add 2 times the volume of water and stir for 20 minutes at a speed of 900 r / min to obtain a mixture for later use. (4) Place the above mixture in a sintering furnace and sinter it at 250°C for 70 minutes. Take it out and crush it initially. Then raise the temperature to 450°C and continue sintering for 80 minutes. Take it out and let it cool. Then continue crushing to control the particle size to 0.2-2 mm to obtain graphitized carbon raiser.

[0021] Following the preparation method described above, different graphitized recarburizing agents were prepared by selecting different petroleum coke and starch materials according to Table 1 below: Table 1 Comparative Example 1: Preparation of graphitized recarburizer-4: (1) Prepare materials according to the following weight parts: 18 parts of pretreated petroleum coke, 15 parts of purified graphite electrode waste, and 9 parts of wood charcoal; (2) The pretreated petroleum coke, purified graphite electrode waste and wood charcoal are mixed, ground and crushed and passed through an 80-mesh sieve. Then the temperature is raised to 2400℃ for graphitization treatment for 2 hours to obtain graphitized raw materials for later use. (3) Place the above graphitized raw material in a sintering furnace and sinter it at 250°C for 70 minutes. Take it out and crush it initially. Then raise the temperature to 450°C and continue sintering for 80 minutes. Take it out and cool it down. Then continue crushing to control the particle size to 0.2-2 mm to obtain graphitized carbon raiser-4.

[0022] Detection: 1. The carbon and sulfur contents of the above-mentioned carbon raisers-1, carbon raiser-2, carbon raiser-3, and carbon raiser-4 were tested (carbon content was measured using a Muffle Furnace-KSW spectrometer, and sulfur content was measured using a PE ICP-2100DV spectrometer). The specific results are shown in Table 2 below: Table 2 2. Test the carbon absorption rate of each group of carbon raisers: Different carburizing agents were selected for HT300 smelting, and the carburization absorption rate was calculated for different addition amounts. The specific results are shown in Table 3 below. Table 3 As shown in the table above, when the amount of carbon raiser-4 increases from 0.6% to 0.7%, the carbon raiser absorption rate differs by 2.6%, indicating that carbon raiser-4 has relatively poor stability, and the overall carbon raiser absorption rate is best with carbon raiser-1.

[0023] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A graphitizing recarburizer, characterized by, The graphitized recarburizer is prepared from the following raw materials by weight: pretreated petroleum coke 15-20 parts, purified graphite electrode waste 10-20 parts, wooden carbon 8-10 parts, sodium hydroxymethyl cellulose 2-4 parts, modified starch 3-5 parts; The pretreated petroleum coke is obtained by soaking petroleum coke in alkali liquor, cleaning with ethanol, drying, filling oxygen at a pressure of 3-5 MPa for high-pressure treatment, and calcining. The modified starch is obtained by gelatinizing cassava starch, microwave shaping, and crushing.

2. The graphitized recarburizer according to claim 1, characterized in that, The specific preparation method of the pretreated petroleum coke comprises the following steps: S1-1, put the petroleum coke in a sodium hydroxide aqueous solution with a pH of 9.5-10, stir at 45-60°C for 30-50 min, then take out and rinse with ethanol until neutral, to obtain alkali-treated petroleum coke; S1-2, put the alkali-treated petroleum coke under a pressure of 3-5 MPa and fill oxygen, react for 20-30 min, then take out, to obtain high-pressure oxidation-treated petroleum coke for standby; S1-3, calcine the high-pressure oxidation-treated petroleum coke at a temperature of 1200-1500°C under a nitrogen atmosphere for 1-2 h, then crush to a particle size of 10-20 mm, to obtain pretreated petroleum coke.

3. The graphitized recarburizer according to claim 1, characterized in that, The preparation method of the modified starch comprises the following steps: S2-1, add cassava starch to 5 times the volume of water, stir uniformly, then stir and sulfonate at a water bath temperature of 60-65°C for 30-40 min, then dry at 45°C until the water content is ≤20%, to obtain gelatinized starch material for standby; S2-2, microwave the above gelatinized starch material in a microwave oven at a power of 280 W to constant weight, to obtain modified starch.

4. The graphitized recarburizer of claim 1, wherein The purified graphite electrode waste is prepared as follows: Grind the graphite electrode waste into a slurry with water, adjust the pH to 4-5 with sulfuric acid, soak, then rinse with clean water, stir and treat in an alkaline solution with a pH of 10-11, then rinse with clean water and dry to obtain.

5. A process for the production of graphitized recarburizer as claimed in any one of claims 1 to 4, characterized in that, The preparation method comprises the following steps: (1) mix and grind the pretreated petroleum coke, purified graphite electrode waste, and wooden carbon, then heat to 2000-2500°C for graphitization treatment for 1.5-2 h, to obtain graphitized raw material for standby; (2) mix the above graphitized raw material with sodium hydroxymethyl cellulose and modified starch, then add 2 times the volume of water, stir thoroughly, to obtain a mixture for standby; (3) put the above mixture into a sintering furnace, preliminarily sinter at a temperature of 200-300°C, take out and crush, then heat to a temperature of 400-500°C for continuous sintering, take out and cool, then continue to crush to control the particle size to 0.2-2 mm, to obtain the graphitized recarburizer.

6. The method of claim 5, wherein: In step (1), the grinding and crushing is through an 80-mesh sieve.

7. The method of claim 5, wherein: In step (2), the stirring speed for thorough stirring is 800-1000 r / min, and the stirring time is 15-20 min.

8. The method of claim 5, wherein: In step (3), the preliminary sintering time is 50-80 min, and the continuous sintering time is 60-90 min.

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