Uniform granulation process of low-nitrogen low-hydrogen carburant

Abstract

The invention relates to the technical field of carburants, and particularly discloses a low-nitrogen low-hydrogen carburant uniform granulation process which comprises the following steps: selecting raw materials, and ball-milling into powder; reducing pressure and removing nitrogen; calcining, dehydrogenating, desulfurizing and denitrifying; carrying out graphitization denitrification and dehydrogenation treatment; mixing the raw materials; uniformly granulating; drying and forming; the raw materials selected by the process are graphite, pitch coke and petroleum coke with relatively low nitrogen content and hydrogen content, and have the characteristics of high fixed carbon, high absorptivity, low sulfur and low nitrogen, and nitrogen atoms in the graphite, pitch coke and petroleum coke are released from a carbon structure in a pressure reduction manner, so that the nitrogen atoms are further removed, and the nitrogen content is reduced. Carrying out deep denitrification and dehydrogenation treatment through calcination dehydrogenation treatment and graphitization treatment; and then a semi-finished product is prepared through foaming treatment, then the semi-finished product is uniformly granulated into a finished product through a granulator, and the finished product improves the quality of a casting.

Description

Technical Field

[0001] The invention relates to the technical field of carburizers, in particular to a uniform granulation process for a low-nitrogen and low-hydrogen carburizer. Background Art

[0002] In the smelting process of steel products, the smelting loss of carbon in the molten iron is often increased due to factors such as long smelting time, insulation time, and overheating time, resulting in a decrease in the carbon content in the molten iron, which leads to the carbon content in the molten iron failing to reach the expected theoretical value of refining; the carbon-containing substance added to make up for the carbon content burned during the steel smelting process is called a recarburizer. The existing recarburizer contains many impurities, and graphitization treatment is often used to reduce impurities. However, the recarburizer after graphitization treatment still has some impurities, and the carbon particles of the graphitized recarburizer have small pores and poor permeability, which cannot increase the carbon particles. The specific surface area of ​​the carbon particles makes it difficult for the carbon particles to contact the molten iron in the molten state, resulting in a decrease in the absorption rate and carbonization efficiency; the existing carbonizers have more nitrogen and hydrogen impurities, and a high nitrogen content may affect the uniform distribution of carbon, resulting in uneven carbonization, or even excessive or insufficient carbon, thereby affecting the quality of castings or smelted products; excessive nitrogen content may cause crack-like pores in castings, affecting the quality of castings; excessive hydrogen content may cause the carbon element in the carbonizer to be diluted, reducing its carbon content and purity, thereby affecting the performance and quality of the product; for this purpose, a uniform granulation process for a low-nitrogen and low-hydrogen carbonizer is provided. Summary of the invention

[0003] The purpose of the present invention is to provide a uniform granulation process for a low-nitrogen and low-hydrogen carburizer in view of the defects of the prior art, so as to solve the problems raised by the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solution: a uniform granulation process of a low-nitrogen and low-hydrogen carburizer, the specific steps of which are as follows:

[0005] Step 1: Raw material selection: graphite, asphalt coke, petroleum coke, foaming agent, water;

[0006] Step 2: ball-milling graphite, asphalt coke and petroleum coke into powders and then mixing them to obtain a mixture A;

[0007] Step 3: The mixture A ground in step 2 is decompressed to release nitrogen atoms in the mixture from the carbon structure, thereby forming nitrogen gas, and the released nitrogen gas is collected and processed. The decompression time is 2-3 hours to obtain a mixture B;

[0008] Step 4: calcination, dehydrogenation, desulfurization and denitrification treatment, the mixture B obtained in step 3 is subjected to calcination and dehydrogenation treatment to obtain a mixture C;

[0009] Step 5: Graphitization, denitrogenation and dehydrogenation treatment; the mixture C obtained in step 4 is graphitized to obtain a mixture D;

[0010] Step 6: Raw material mixing treatment: Cool the mixture D obtained in step 5, add water and stir for 10-15 minutes, then add a foaming agent and stir for 10-30 minutes to obtain a mixture E;

[0011] Step 7: uniform granulation: the mixture E obtained in step 6 is granulated by a granulator to obtain a mixture F;

[0012] Step 8: Drying and molding: The mixture F in step 7 is heated and dried to obtain a finished carburizer.

[0013] As a preferred technical solution of the present invention, the graphite, asphalt coke, petroleum coke, foaming agent and water in step 1 are respectively as follows in parts by weight: graphite 45-55, asphalt coke 35-40, petroleum coke 30-40, foaming agent 4-8 and water 200-250.

[0014] As a preferred technical solution of the present invention, the particle size of the ball milling in step 2 is 0.2-0.6 mm.

[0015] As a preferred technical solution of the present invention, the foaming agent is sodium bicarbonate.

[0016] As a preferred technical solution of the present invention, the calcination temperature of step 4 is 1800-2000°C, and the calcination time is 20-24h.

[0017] As a preferred technical solution of the present invention, the graphitization temperature of step 5 is 3000-3500° C., and the graphitization time is 1-2 h.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: the raw materials selected by the process of the present invention are all graphite, asphalt coke and petroleum coke with low nitrogen and hydrogen contents, which have the characteristics of high fixed carbon, high absorption rate, low sulfur and low nitrogen, and the nitrogen atoms in the graphite, asphalt coke and petroleum coke are released from the carbon structure by means of decompression, thereby further removing the nitrogen atoms, and then undergoing deep denitrification and dehydrogenation treatment by calcination dehydrogenation treatment and graphitization treatment; thereby reducing the nitrogen and hydrogen in the raw materials, and then undergoing foaming treatment to make semi-finished products, thereby improving the permeability of the pores of the carbon particles, and then being uniformly granulated into finished products by a granulator, and the finished products improve the quality of the castings. DETAILED DESCRIPTION

[0019] The preferred embodiments of the present invention are described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0020] Embodiment 1: The present invention provides a technical solution: a uniform granulation process of a low-nitrogen and low-hydrogen carburizer, the specific steps are as follows:

[0021] Step 1: Raw material selection: graphite, asphalt coke, petroleum coke, foaming agent, and water are selected; the weight proportions are as follows: graphite 45, asphalt coke 35, petroleum coke 30, sodium bicarbonate 4, and water 200;

[0022] Step 2: ball-milling graphite, asphalt coke and petroleum coke into powders and then mixing them to obtain a mixture A, wherein the particle size of the ball-milled particles is 0.2-0.6 mm;

[0023] Step 3: The mixture A ground in step 2 is decompressed to release nitrogen atoms in the mixture from the carbon structure, thereby forming nitrogen gas, and the released nitrogen gas is collected and processed. The decompression time is 2-3 hours to obtain a mixture B;

[0024] Step 4: Calcination, dehydrogenation, desulfurization and denitrification treatment. The mixture B obtained in step 3 is subjected to calcination and dehydrogenation treatment at a temperature of 1800° C. for 20 hours to obtain a mixture C.

[0025] Step 5: graphitization denitrogenation and dehydrogenation treatment; the mixture C obtained in step 4 is graphitized at a graphitization temperature of 3000° C. for a graphitization time of 1 h to obtain a mixture D;

[0026] Step 6: Raw material mixing treatment: Cool the mixture D obtained in step 5, add water and stir for 10-15 minutes, then add a foaming agent and stir for 10-30 minutes to obtain a mixture E;

[0027] Step 7: uniform granulation: the mixture E obtained in step 6 is granulated by a granulator to obtain a mixture F;

[0028] Step 8: Drying and molding: The mixture F in step 7 is heated and dried to obtain a finished carburizer.

[0029] Embodiment 2: The present invention provides a technical solution: a uniform granulation process of a low-nitrogen and low-hydrogen carburizer, the specific steps are as follows:

[0030] Step 1: Raw material selection: graphite, asphalt coke, petroleum coke, foaming agent, and water are selected; the weight proportions are as follows: 50 parts of graphite, 38 parts of asphalt coke, 35 parts of petroleum coke, 6 parts of sodium bicarbonate, and 220 parts of water;

[0031] Step 2: ball-milling graphite, asphalt coke and petroleum coke into powders and then mixing them to obtain a mixture A, wherein the particle size of the ball-milled particles is 0.2-0.6 mm;

[0032] Step 3: The mixture A ground in step 2 is decompressed to release nitrogen atoms in the mixture from the carbon structure, thereby forming nitrogen gas, and the released nitrogen gas is collected and processed. The decompression time is 2-3 hours to obtain a mixture B;

[0033] Step 4: Calcination, dehydrogenation, desulfurization and denitrification treatment. The mixture B obtained in step 3 is subjected to calcination and dehydrogenation treatment at a calcination temperature of 1900° C. for 22 hours to obtain a mixture C.

[0034] Step 5: graphitization denitrogenation and dehydrogenation treatment; the mixture C obtained in step 4 is graphitized at a graphitization temperature of 3400° C. for a graphitization time of 1.5 h to obtain a mixture D;

[0035] Step 6: Raw material mixing treatment: Cool the mixture D obtained in step 5, add water and stir for 10-15 minutes, then add a foaming agent and stir for 10-30 minutes to obtain a mixture E;

[0036] Step 7: uniform granulation: the mixture E obtained in step 6 is granulated by a granulator to obtain a mixture F;

[0037] Step 8: Drying and molding: The mixture F in step 7 is heated and dried to obtain a finished carburizer.

[0038] Embodiment 3: The present invention provides a technical solution: a uniform granulation process of a low-nitrogen and low-hydrogen carburizer, the specific steps are as follows:

[0039] Step 1: Raw material selection: graphite, asphalt coke, petroleum coke, foaming agent, and water are selected; the weight proportions are as follows: 55 graphite, 40 asphalt coke, 40 petroleum coke, 8 sodium bicarbonate, and 250 water;

[0040] Step 2: ball-milling graphite, asphalt coke and petroleum coke into powders and then mixing them to obtain a mixture A, wherein the particle size of the ball-milled particles is 0.2-0.6 mm;

[0041] Step 3: The mixture A ground in step 2 is decompressed to release nitrogen atoms in the mixture from the carbon structure, thereby forming nitrogen gas, and the released nitrogen gas is collected and processed. The decompression time is 2-3 hours to obtain a mixture B;

[0042] Step 4: calcination, dehydrogenation, desulfurization and denitrification treatment, the mixture B obtained in step 3 is subjected to calcination and dehydrogenation treatment, the calcination temperature is 2000° C., the calcination time is 24 hours, and a mixture C is obtained;

[0043] Step 5: graphitization denitrogenation and dehydrogenation treatment; the mixture C obtained in step 4 is graphitized at a graphitization temperature of 3500° C. for a graphitization time of 2 h to obtain a mixture D;

[0044] Step 6: Raw material mixing treatment: Cool the mixture D obtained in step 5, add water and stir for 10-15 minutes, then add a foaming agent and stir for 10-30 minutes to obtain a mixture E;

[0045] Step 7: uniform granulation: the mixture E obtained in step 6 is granulated by a granulator to obtain a mixture F;

[0046] Step 8: Drying and molding: The mixture F in step 7 is heated and dried to obtain a finished carburizer.

[0047] Comparative example: carburizer purchased on the market;

[0048] The products obtained in Examples 1-3 and the recarburizers purchased on the market were tested for nitrogen, hydrogen and sulfur, as shown in the following table:

[0049]

[0050]

[0051] In summary, the recarburizer obtained by the process of the present invention has a high carbon content and low sulfur content, hydrogen content and nitrogen content. When used, the quality of the casting can be improved.

[0052] The above embodiments only express the implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Claims

1. A process for uniformly granulating a low-nitrogen and low-hydrogen carburizer, characterized in that: The specific steps are as follows: Step 1: Raw material selection: graphite, asphalt coke, petroleum coke, foaming agent, water; Step 2: ball-milling graphite, asphalt coke and petroleum coke into powders and then mixing them to obtain a mixture A; Step 3: The mixture A ground in step 2 is decompressed to release nitrogen atoms in the mixture from the carbon structure, thereby forming nitrogen gas, and the released nitrogen gas is collected and processed. The decompression time is 2-3 hours to obtain a mixture B; Step 4: calcination, dehydrogenation, desulfurization and denitrification treatment, the mixture B obtained in step 3 is subjected to calcination and dehydrogenation treatment to obtain a mixture C; Step 5: Graphitization, denitrogenation and dehydrogenation treatment; the mixture C obtained in step 4 is graphitized to obtain a mixture D; Step 6: Raw material mixing treatment: Cool the mixture D obtained in step 5, add water and stir for 10-15 minutes, then add a foaming agent and stir for 10-30 minutes to obtain a mixture E; Step 7: uniform granulation: the mixture E obtained in step 6 is granulated by a granulator to obtain a mixture F; Step 8: Drying and molding: The mixture F in step 7 is heated and dried to obtain a finished carburizer.

2. The uniform granulation process of low-nitrogen and low-hydrogen carburizer according to claim 1, characterized in that: The graphite, asphalt coke, petroleum coke, foaming agent and water in step 1 are respectively as follows in parts by weight: 45-55 graphite, 35-40 asphalt coke, 30-40 petroleum coke, 4-8 foaming agent and 200-250 water.

3. The uniform granulation process of low-nitrogen and low-hydrogen carburizer according to claim 1, characterized in that: The particle size of the ball mill in step 2 is 0.2-0.6 mm.

4. The uniform granulation process of low-nitrogen and low-hydrogen carburizer according to claim 1, characterized in that: The foaming agent is sodium bicarbonate.

5. The uniform granulation process of low-nitrogen and low-hydrogen carburizer according to claim 1, characterized in that: The calcination temperature of step 4 is 1800-2000° C., and the calcination time is 20-24 hours.

6. The uniform granulation process of low-nitrogen and low-hydrogen carburizer according to claim 1, characterized in that: The graphitization temperature of step 5 is 3000-3500° C., and the graphitization time is 1-2 h.

Images