Raw material composition for needle coke, green coke and its manufacturing method, needle coke for graphite electrodes and its manufacturing method, manufacturing method for graphite electrodes
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- MITSUBISHI CHEM CORP
- Filing Date
- 2022-10-11
- Publication Date
- 2026-06-23
AI Technical Summary
【0010】 本発明によれば、原料ピッチ中にインヒビターが内包されているニードルコークス用原料組成物を用いることにより、ニードルコークスの製造時に多大なコストをかけることなく、ニードルコークスのパッフィングを抑制し、黒鉛電極の製造歩留まりと特性を向上させることができる。
Smart Images
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Figure 0007878003000001
Abstract
Claims
1. A raw material composition for needle coke used in the manufacture of graphite electrodes, The raw material pitch contains an inhibitor for graphite electrode manufacturing. A raw material composition for needle coke, wherein the inhibitor for manufacturing graphite electrodes comprises a composite oxide having the following elements (Mα) and (Mβ). Element (Mα): At least one metallic element selected from the group consisting of K, Sc, alkaline earth metal elements, and rare earth metal elements. Element (Mβ): At least one element selected from the group consisting of Group 4, Group 8, Group 9, Group 10, Group 13, Group 14, and Group 15 of the long-period periodic table.
2. The raw material composition for needle coke according to claim 1, wherein the compositional formula of the composite oxide is the following formula (1). Ma ３－ｘ Mβ １－ｙ O ５－ｚ ・・・(1) (In the equation, 0 ≤ x < 3, 0 ≤ y < 1, and 0 ≤ z < 5.)
3. The raw material composition for needle coke according to claim 1, wherein the raw material pitch comprises one or more pitches derived from coal tar, FCC decanted oil, ethylene heavy end, petroleum residue, petroleum waste, biomass oil, or biomasterl.
4. The raw material composition for needle coke according to claim 1, wherein when X is the ratio (by weight) of the inhibitor for manufacturing graphite electrodes to the total weight of the raw material pitch, 0.01 < X < 5.
5. Green coke, which is a carbide of the raw material composition for needle coke according to any one of claims 1 to 4.
6. The green coke according to claim 5, wherein when Y is the ratio (by weight) of the inhibitor for graphite electrode production to the total weight of green coke, 0.02 < Y < 10.
7. A method for producing green coke, comprising coking a needle coke raw material composition according to any one of claims 1 to 4 to obtain green coke.
8. A method for producing green coke according to claim 7, wherein the coking temperature is 300°C or higher and 600°C or lower.
9. The method for producing green coke according to claim 7, wherein the pressure during caulking is 0.01 MPa or more and 0.99 MPa or less in gauge pressure.
10. A method for producing green coke according to claim 7, comprising mixing the graphite electrode manufacturing inhibitor and the raw material pitch in a tank and coking it.
11. A method for producing green coke according to claim 7, comprising mixing the graphite electrode manufacturing inhibitor and the raw material pitch in a pipe and then caulking it.
12. Needle coke for graphite electrodes, which is a carbonized form of green coke as described in claim 5.
13. The needle coke for graphite electrodes according to claim 12, wherein when Z is the ratio (weight %) of the inhibitor for manufacturing graphite electrodes to the total weight of the needle coke for graphite electrodes, 0.02 < Z < 15.
14. The puffing value P calculated using the following formula (I) for the test piece created in the following evaluation test (i) ２８００ Needle coke for graphite electrodes according to claim 12, wherein the content is 0.60% or less. P ２８００ =(L2-L1) / L1×100 ・・・(I) However, L1 and L2 in equation (I) have the following meanings. L1: Thickness of the test piece before firing (mm) L2: Thickness of the test piece after firing at 2800°C (mm) <Evaluation Test (i)> The graphite electrode needle coke and 30% by weight of binder pitch relative to the graphite electrode needle coke are mixed and kneaded for 5 minutes while heating at 165°C. This is molded into a disc shape of 20 mmΦ × 3 mm to 15 mm, and fired in a firing furnace at 1000°C for 3 hours to burn off the binder pitch and create a test piece. The test piece is fired at a heating rate of 20°C / min to 2800°C, and L1 and L2 of the test piece are measured before and after firing.
15. The puffing value P calculated using the following formula (II) for the test piece created in the following evaluation test (ii) １７００－２１００ Needle coke for graphite electrodes according to claim 12, wherein the content is 0.60% or less. P １７００－２１００ =(L3-L4) / L5×100 ・・・(II) However, L3, L4, and L5 in equation (II) have the following meanings. L3: Thickness of the test piece at 2100°C firing (mm) L4: Thickness of the test piece at 1700°C firing (mm) L5: Thickness of the test piece at 1000°C firing (mm) <Evaluation Test (ii)> The graphite electrode needle coke and 30% by weight of binder pitch relative to the graphite electrode needle coke are mixed and kneaded for 5 minutes while heating at 165°C. This is molded into a disc shape of 20 mmΦ × 3 mm to 15 mm and fired in a firing furnace at 1000°C for 3 hours to burn off the binder pitch and create a test piece. The test piece is fired at a heating rate of 20°C / min up to 2800°C using a heating thermal expansion measuring device, and L3, L4, and L5 of the test piece are measured during firing.
16. In the evaluation test (i), a test piece is prepared in the same manner except that needle coke using raw material pitch not containing the inhibitor for manufacturing the graphite electrode is used, and the puffing value (blank) calculated by the formula (I) of the test piece is taken as P ２８００ｂ When it is ２８００ / P ２８００ｂ The needle coke for a graphite electrode according to claim 14, wherein the ratio of the puffing values calculated by is less than 1.
17. In the evaluation test (ii) described above, a test piece was prepared in the same manner as in the evaluation test (ii), except that needle coke made from raw material pitch that does not contain the inhibitor for graphite electrode manufacturing was used, and the puffing value (blank) of the test piece calculated by formula (II) described above was set to P １７００－２１００ｂ In that case, P １７００－２１００ / P １７００－２１００ｂ Needle coke for graphite electrodes according to claim 15, wherein the ratio of the puffing values calculated is less than 1.
18. A method for producing needle coke for graphite electrodes, comprising calcining the raw coke described in claim 5 at a temperature of 1000°C to 1700°C to obtain needle coke.
19. A method for manufacturing a graphite electrode, comprising using needle coke for graphite electrodes as described in claim 12 as aggregate and obtaining a graphite electrode by graphitization treatment.
20. The method for manufacturing a graphite electrode according to claim 19, wherein the temperature of the graphitization treatment is 2500°C or more and 3000°C or less.
21. The method for manufacturing a graphite electrode according to claim 19, wherein the proportion of the inhibitor for manufacturing the graphite electrode remaining in the graphite electrode is 0.01% by weight or less.