JP5707668B2 - Hot copper decoppering method - Google Patents
Hot copper decoppering method Download PDFInfo
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- JP5707668B2 JP5707668B2 JP2009006296A JP2009006296A JP5707668B2 JP 5707668 B2 JP5707668 B2 JP 5707668B2 JP 2009006296 A JP2009006296 A JP 2009006296A JP 2009006296 A JP2009006296 A JP 2009006296A JP 5707668 B2 JP5707668 B2 JP 5707668B2
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- copper
- hot metal
- refining agent
- iron
- copper removal
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- 239000010949 copper Substances 0.000 title claims description 164
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 title claims description 154
- 229910052802 copper Inorganic materials 0.000 title claims description 154
- 238000000034 method Methods 0.000 title claims description 48
- 229910052751 metal Inorganic materials 0.000 claims description 127
- 239000002184 metal Substances 0.000 claims description 127
- 238000007670 refining Methods 0.000 claims description 69
- 239000003795 chemical substances by application Substances 0.000 claims description 66
- 229910000831 Steel Inorganic materials 0.000 claims description 47
- 239000010959 steel Substances 0.000 claims description 47
- 239000011734 sodium Substances 0.000 claims description 42
- MBMLMWLHJBBADN-UHFFFAOYSA-N Ferrous sulfide Chemical compound [Fe]=S MBMLMWLHJBBADN-UHFFFAOYSA-N 0.000 claims description 23
- 102000005298 Iron-Sulfur Proteins Human genes 0.000 claims description 23
- 108010081409 Iron-Sulfur Proteins Proteins 0.000 claims description 23
- 229910000796 S alloy Inorganic materials 0.000 claims description 23
- 150000001339 alkali metal compounds Chemical class 0.000 claims description 22
- 238000006243 chemical reaction Methods 0.000 claims description 21
- 238000002844 melting Methods 0.000 claims description 12
- 230000008018 melting Effects 0.000 claims description 12
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Chemical compound [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 claims description 11
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 9
- 230000008569 process Effects 0.000 claims description 9
- 229910052708 sodium Inorganic materials 0.000 claims description 9
- 238000005255 carburizing Methods 0.000 claims description 8
- 238000010907 mechanical stirring Methods 0.000 claims description 8
- 239000000463 material Substances 0.000 claims description 7
- 229910052783 alkali metal Inorganic materials 0.000 claims description 5
- 150000001340 alkali metals Chemical class 0.000 claims description 5
- 229910001610 cryolite Inorganic materials 0.000 claims description 5
- 239000011775 sodium fluoride Substances 0.000 claims description 5
- 235000013024 sodium fluoride Nutrition 0.000 claims description 5
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 4
- 150000001875 compounds Chemical class 0.000 claims description 4
- 229910052744 lithium Inorganic materials 0.000 claims description 4
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims description 3
- 239000011591 potassium Substances 0.000 claims description 3
- 229910052700 potassium Inorganic materials 0.000 claims description 3
- NROKBHXJSPEDAR-UHFFFAOYSA-M potassium fluoride Chemical compound [F-].[K+] NROKBHXJSPEDAR-UHFFFAOYSA-M 0.000 claims description 3
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims description 2
- 150000004649 carbonic acid derivatives Chemical class 0.000 claims description 2
- ORUIBWPALBXDOA-UHFFFAOYSA-L magnesium fluoride Chemical compound [F-].[F-].[Mg+2] ORUIBWPALBXDOA-UHFFFAOYSA-L 0.000 claims description 2
- 150000004763 sulfides Chemical class 0.000 claims description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 claims 1
- 229910001634 calcium fluoride Inorganic materials 0.000 claims 1
- 150000004673 fluoride salts Chemical class 0.000 claims 1
- 229910001635 magnesium fluoride Inorganic materials 0.000 claims 1
- 235000003270 potassium fluoride Nutrition 0.000 claims 1
- 239000011698 potassium fluoride Substances 0.000 claims 1
- 238000003672 processing method Methods 0.000 claims 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 47
- 239000002893 slag Substances 0.000 description 30
- 229910052717 sulfur Inorganic materials 0.000 description 28
- 239000011593 sulfur Substances 0.000 description 27
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 26
- 150000004820 halides Chemical class 0.000 description 26
- 229910052742 iron Inorganic materials 0.000 description 24
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 21
- 238000012360 testing method Methods 0.000 description 20
- 230000004907 flux Effects 0.000 description 18
- 238000003756 stirring Methods 0.000 description 14
- 238000006477 desulfuration reaction Methods 0.000 description 10
- 230000023556 desulfurization Effects 0.000 description 10
- 229910000029 sodium carbonate Inorganic materials 0.000 description 10
- 235000017550 sodium carbonate Nutrition 0.000 description 10
- 238000009628 steelmaking Methods 0.000 description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 9
- 239000000571 coke Substances 0.000 description 9
- 229910052799 carbon Inorganic materials 0.000 description 8
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 6
- 239000003610 charcoal Substances 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 238000001704 evaporation Methods 0.000 description 4
- AMWRITDGCCNYAT-UHFFFAOYSA-L hydroxy(oxo)manganese;manganese Chemical compound [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 description 4
- JHJLBTNAGRQEKS-UHFFFAOYSA-M sodium bromide Chemical compound [Na+].[Br-] JHJLBTNAGRQEKS-UHFFFAOYSA-M 0.000 description 4
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 3
- 238000007664 blowing Methods 0.000 description 3
- 239000000460 chlorine Substances 0.000 description 3
- AQKDYYAZGHBAPR-UHFFFAOYSA-M copper;copper(1+);sulfanide Chemical compound [SH-].[Cu].[Cu+] AQKDYYAZGHBAPR-UHFFFAOYSA-M 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 230000008020 evaporation Effects 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 239000011780 sodium chloride Substances 0.000 description 3
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 description 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 2
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 2
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- 238000013019 agitation Methods 0.000 description 2
- 229910001508 alkali metal halide Inorganic materials 0.000 description 2
- 150000008045 alkali metal halides Chemical class 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Substances BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 description 2
- 229910052794 bromium Inorganic materials 0.000 description 2
- 229910052801 chlorine Inorganic materials 0.000 description 2
- 239000011737 fluorine Substances 0.000 description 2
- 229910052731 fluorine Inorganic materials 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 238000011835 investigation Methods 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 229910000027 potassium carbonate Inorganic materials 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000004064 recycling Methods 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 239000005997 Calcium carbide Substances 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 241001424392 Lucia limbaria Species 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 238000003723 Smelting Methods 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 229910052977 alkali metal sulfide Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- OMZSGWSJDCOLKM-UHFFFAOYSA-N copper(II) sulfide Chemical compound [S-2].[Cu+2] OMZSGWSJDCOLKM-UHFFFAOYSA-N 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000005261 decarburization Methods 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000005485 electric heating Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- -1 fluorine (F) Chemical class 0.000 description 1
- 238000005755 formation reaction Methods 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 238000007885 magnetic separation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000001103 potassium chloride Substances 0.000 description 1
- 235000011164 potassium chloride Nutrition 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 150000003463 sulfur Chemical class 0.000 description 1
- CLZWAWBPWVRRGI-UHFFFAOYSA-N tert-butyl 2-[2-[2-[2-[bis[2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]amino]-5-bromophenoxy]ethoxy]-4-methyl-n-[2-[(2-methylpropan-2-yl)oxy]-2-oxoethyl]anilino]acetate Chemical compound CC1=CC=C(N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)C(OCCOC=2C(=CC=C(Br)C=2)N(CC(=O)OC(C)(C)C)CC(=O)OC(C)(C)C)=C1 CLZWAWBPWVRRGI-UHFFFAOYSA-N 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Manufacture And Refinement Of Metals (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Description
本発明は、溶銑中に含まれる銅を除去する方法に関し、詳しくは、鉄源として鋼屑（鉄系スクラップ）を使用して高級鋼を製造する場合に、鋼屑中の銅に起因する、品質上の問題となる溶銑中の銅を除去する方法に関するものである。 The present invention relates to a method for removing copper contained in hot metal, specifically, when producing high-grade steel using steel scrap (iron-based scrap) as an iron source, resulting from copper in the steel scrap. The present invention relates to a method for removing copper in hot metal, which is a quality problem.
製鋼過程で使用する鉄源は、鉄鉱石を高炉で還元して得られる溶銑が主体であるが、鉄鋼材料の加工工程で発生する鋼屑や、建築物及び機械製品などの老朽化に伴って発生する鋼屑も、かなりの量が使用されている。高炉での溶銑の製造には、鉄鉱石を還元し且つ溶融するための多大なエネルギーを要するのに対し、鋼屑は溶解熱のみを必要としており、製鋼過程で鋼屑を利用した場合には、鉄鉱石の還元熱分のエネルギー使用量を少なくすることができるという利点がある。従って、省エネルギー及びＣＯ2削減による地球温暖化防止の観点からも、鋼屑利用の促進が望まれている。 The iron source used in the steelmaking process is mainly hot metal obtained by reducing iron ore in a blast furnace, but with the aging of steel scraps, buildings and machinery products generated in the processing process of steel materials A considerable amount of steel scrap is also used. The production of hot metal in the blast furnace requires a great deal of energy to reduce and melt iron ore, whereas steel scrap requires only heat of melting, and when steel scrap is used in the steelmaking process, There is an advantage that the amount of energy used for reducing heat of iron ore can be reduced. Therefore, from the viewpoint of energy saving and prevention of global warming by reducing CO 2, it is desired to promote the use of steel scrap.
ところで、鋼屑を再生利用する際に、これら鋼屑に随伴する銅及び錫に代表されるトランプエレメントが、鋼屑溶解の過程で不可避的に溶鉄中に混入する。トランプエレメントは鋼の性質を損なう成分であり、一定の濃度以下に保つ必要がある。そのため、高級鋼を製造する鉄源として、銅や錫を含む低級鋼屑の利用には限界があった。しかしながら、近年の鋼屑発生量の増加及びＣＯ2発生削減のための鋼屑増使用の要請を勘案すると、低級鋼屑の再生利用を進める必要がある。 By the way, when recycling steel scraps, trump elements represented by copper and tin accompanying these steel scraps are inevitably mixed in the molten iron in the process of steel scrap melting. The trump element is a component that impairs the properties of steel and must be kept below a certain concentration. Therefore, there is a limit to the use of low-grade steel scrap containing copper and tin as an iron source for producing high-grade steel. However, considering the recent increase in steel scrap generation and the demand for increased use of steel scrap to reduce CO 2 generation, it is necessary to promote recycling of lower steel scrap.
現在の低級鋼屑を使用するための実用化技術としては、鋼屑を物理的に分解して有害な部分を人力や磁力選別などの方法で分離し、有害な部分を分離したものを、有害成分をほとんど含有しない原料に配合して、鋼材の材料特性上問題のない範囲内で使用する以外に、有効な方法はない。このような方法では、使用済み自動車などの鋼屑を大量に再生利用することは不可能であり、今後予想される鋼屑多量発生時代に対応する鋼屑中の銅の除去技術としては、十分な解決策には成り得ない。 The practical technology for using the current low-grade steel scraps is that the steel scraps are physically decomposed and harmful parts are separated by methods such as human power and magnetic separation, and the harmful parts are separated. There is no effective method other than blending with raw materials containing almost no components and using them within the range where there is no problem in the material properties of the steel. With such a method, it is impossible to recycle a large amount of scrap steel from used cars, etc., and it is sufficient as a technology for removing copper in steel scrap corresponding to the era of the large amount of scrap scrap expected in the future. Cannot be a good solution.
一方、溶鉄に混入した後の脱銅方法について、以下に述べる原理的発明が公知になっている。つまり、含銅高炭素溶鉄とＦｅＳ−Ｎａ2Ｓ系フラックスとを接触させ、溶鉄中の銅成分をＣｕ2Ｓとしてフラックス中に分離除去する原理的技術知見が、非特許文献１及び非特許文献２に報告されている。この技術は、銅の除去技術として、前述の物理的除去方法に対して、より広い適用の可能性を提案するものである。但し、この方法では、ＦｅＳ−Ｎａ2Ｓ系フラックスが溶融して溶鉄上に形成されるスラグ中のＣｕ濃度と溶鉄中のＣｕ濃度との比である分配比が高々３０程度であり、スラグに充分な撹拌を与えて分配比を低下させないようにする必要がある。 On the other hand, the principle invention described below is known about the copper removal method after mixing in molten iron. That is, contacting the copper-containing high carbon molten iron and FeS-Na 2 S based flux principle technology knowledge to separate off in the flux of the copper component in the molten iron as Cu 2 S is, non-patent documents 1 and 2 is reported. This technique proposes a wider applicability to the above-described physical removal method as a copper removal technique. However, in this method, the distribution ratio, which is the ratio of the Cu concentration in the slag formed on the molten iron by melting the FeS-Na 2 S-based flux and the Cu concentration in the molten iron, is about 30 at most. It is necessary to give sufficient agitation so as not to lower the distribution ratio.
この原理的技術知見に基づいた脱銅処理方法として、特許文献１には、含銅鋼屑を加炭溶融して含銅高炭素溶鉄とした後、脱銅用の精錬剤として、Ｎａ2Ｓを主成分とするフラックスを添加し、溶銑とＮａ2Ｓを主成分とするフラックスとを接触反応させて、溶鉄中の銅成分をＣｕ2ＳとしてＮａ2Ｓ系フラックス中に分離除去する方法が開示されている。 As the copper removal treatment method based on this principle technical knowledge, Patent Document 1, after the copper-containing high carbon molten iron and carburized melt the copper-containing steel scraps, as refining agent for copper removal, Na 2 S Is a method in which a flux containing, as a main component, is added, a hot metal and a flux containing Na 2 S as a main component are brought into contact with each other, and the copper component in the molten iron is separated and removed as Cu 2 S into the Na 2 S-based flux. It is disclosed.
但し、特許文献１では３４０ｋｇ／ｔ-鉄もの大量のフラックスを用いて精錬処理を行っており、精錬コストやフラックスのハンドリングの点で実用化が困難である。更には、反応温度を１２００〜１５００℃に保つための電気加熱装置を備えるとともに、大気との接触を断つための有蓋の反応容器を使用しており、設備が大掛かりであり、設備的な観点からみても実用化技術として確立しているとは言いがたい。 However, in Patent Document 1, the refining process is performed using a large amount of flux as high as 340 kg / t-iron, and it is difficult to put it to practical use in terms of refining costs and flux handling. Furthermore, it is equipped with an electric heating device for maintaining the reaction temperature at 1200 to 1500 ° C., and uses a covered reaction vessel for cutting off contact with the atmosphere. It is hard to say that it has been established as a practical technology.
本発明は上記事情に鑑みてなされたもので、その目的とするところは、鉄源として銅含有鋼屑を使用し、該鋼屑を加炭溶解して製造される溶銑中の銅を、ＦｅＳ−Ｎａ2Ｓ系フラックスなどの硫黄含有フラックスにより除去するに際し、大がかりな設備を必要とせずに効率良く銅を除去することのできる、溶銑の脱銅処理方法を提供することである。 The present invention has been made in view of the above circumstances, and its object is to use copper-containing steel scrap as an iron source, and to add copper in hot metal produced by carburizing and melting the steel scrap to FeS. It is to provide a hot metal decoppering method capable of efficiently removing copper without requiring a large-scale facility when removing with a sulfur-containing flux such as a Na 2 S flux.
上記課題を解決するための第１の発明に係る溶銑の脱銅処理方法は、反応容器内に収容された銅含有溶銑に、精錬剤として、アルカリ金属の化合物と鉄−硫黄合金とハロゲン化物とを添加し、前記精錬剤により銅含有溶銑中の銅を吸収・除去することを特徴とするものである。 The method for removing copper from hot metal according to the first aspect of the present invention for solving the above-described problem includes a copper-containing hot metal contained in a reaction vessel, a refining agent, an alkali metal compound, an iron-sulfur alloy, and a halide. And the copper in the copper-containing hot metal is absorbed and removed by the refining agent.
第２の発明に係る溶銑の脱銅処理方法は、第１の発明において、前記銅含有溶銑は、銅含有鋼屑を加炭溶解して製造されたものであることを特徴とするものである。 The hot metal decoppering method according to the second invention is characterized in that, in the first invention, the copper-containing hot metal is produced by carburizing and dissolving copper-containing steel scraps. .
第３の発明に係る溶銑の脱銅処理方法は、第１または第２の発明において、前記アルカリ金属の化合物は、Ｎａ2ＣＯ3及び／またはＫ2ＣＯ3を主成分とする材料であることを特徴とするものである。 In the hot metal decopperizing method according to the third invention, in the first or second invention, the alkali metal compound is a material mainly composed of Na 2 CO 3 and / or K 2 CO 3. It is characterized by.
第４の発明に係る溶銑の脱銅処理方法は、第１ないし第３の発明の何れかにおいて、前記精錬剤は、ハロゲン化物と、アルカリ金属の化合物及び／または鉄−硫黄合金とが予め混合されたものであることを特徴とするものである。 According to a fourth aspect of the present invention, there is provided a hot metal decoppering method according to any one of the first to third aspects, wherein the refining agent is a mixture of a halide, an alkali metal compound and / or an iron-sulfur alloy. It is characterized by being made.
第５の発明に係る溶銑の脱銅処理方法は、第１ないし第４の発明の何れかにおいて、前記精錬剤によって銅を除去する前の銅含有溶銑は、温度が１２５０℃以上１４００℃以下であることを特徴とするものである。 In any one of the first to fourth inventions, the copper-containing hot metal before removing copper by the refining agent has a temperature of 1250 ° C. or higher and 1400 ° C. or lower. It is characterized by being.
第６の発明に係る溶銑の脱銅処理方法は、第１ないし第５の発明の何れかにおいて、前記脱銅処理を機械攪拌式精錬装置で行うことを特徴とするものである。 The hot metal decoppering method according to a sixth aspect of the present invention is characterized in that, in any of the first to fifth aspects, the decoppering process is performed by a mechanical stirring type refining apparatus.
本発明によれば、銅含有鋼屑を加炭溶解して製造した溶銑中の銅を分離・除去するための精錬剤として、アルカリ金属の化合物、例えばＮａ2ＣＯ3を主成分とする材料と、鉄−硫黄合金と、ハロゲン化物とを使用するので、添加されるハロゲン化物とアルカリ金属の化合物中のアルカリとでアルカリ金属のハロゲン化物が形成され、これによりアルカリ金属の蒸気圧が低下し、アルカリ金属化合物の蒸発ロスが減少し、少ないアルカリ金属化合物で効率良く溶銑を脱銅処理することが実現される。その結果、製鋼用溶銑の原料として従来使用困難であった、銅を多量に含む鋼屑の高級鋼への適用が可能となり、低級屑の利用促進やＣＯ2削減などの工業上有益な効果がもたらされる。 According to the present invention, as a refining agent for separating and removing copper in hot metal produced by carburizing and dissolving copper-containing steel scrap, an alkali metal compound, for example, a material mainly composed of Na 2 CO 3 and Since an iron-sulfur alloy and a halide are used, an alkali metal halide is formed by the added halide and the alkali in the alkali metal compound, thereby reducing the vapor pressure of the alkali metal, The evaporation loss of the alkali metal compound is reduced, and it is possible to efficiently remove the hot metal with a small amount of alkali metal compound. As a result, steel scrap containing a large amount of copper, which has been difficult to use as a raw material for hot metal for steelmaking, can be applied to high-grade steel, and industrially beneficial effects such as promoting the use of low-grade scrap and reducing CO 2 are achieved. Brought about.
以下、本発明を具体的に説明する。 Hereinafter, the present invention will be specifically described.
銅含有鋼屑を加炭溶解して炭素を含有した製鋼用溶銑を製造すると、鋼屑中の銅はほぼ全量が溶銑中に溶解する。本発明者らは、硫黄含有フラックスを精錬剤として用いて溶銑中の銅を硫化銅（Ｃｕ2Ｓ）として除去することに着目し、鋭意調査・研究を行った。その結果、溶銑からの脱銅反応には、（１）反応容器内の溶銑及び精錬剤の硫黄含有量を高めること、（２）精錬剤の塩基性を高めてＣｕ2Ｓの活量を低下させること、（３）精錬剤の溶融性を高めること、が重要であることを突き止めた。 When the hot metal for steelmaking containing carbon is produced by carburizing and dissolving copper-containing steel scrap, almost all of the copper in the steel scrap is dissolved in the hot metal. The present inventors paid attention to removing copper in molten iron as copper sulfide (Cu 2 S) using a sulfur-containing flux as a refining agent, and conducted earnest investigations and studies. As a result, in the copper removal reaction from hot metal, (1) to increase the sulfur content of the hot metal and the refining agent in the reaction vessel, (2) to increase the basicity of the refining agent and to reduce the Cu 2 S activity And (3) increasing the melting property of the refining agent was found to be important.
先ず、（１）の硫黄含有量については、精錬剤中の硫黄含有量を高めてもよいし、溶銑中の硫黄濃度を高めても、どちらでも構わないことが分かった。精錬剤中の硫黄含有量を高める手段としては、工業的にも広く利用されている鉄−硫黄合金（フェロサルファー）を用いることがコスト面でも好ましい。また、鉄−硫黄合金は溶銑中の硫黄濃度を高めるために用いることも当然可能である。 First, with regard to the sulfur content of (1), it was found that either the sulfur content in the refining agent may be increased or the sulfur concentration in the hot metal may be increased. As a means for increasing the sulfur content in the refining agent, it is preferable in terms of cost to use an iron-sulfur alloy (ferrosulfur) widely used industrially. Further, it is naturally possible to use the iron-sulfur alloy in order to increase the sulfur concentration in the hot metal.
次に、（２）及び（３）について説明する。連続鋳造機で使用されるモールドパウダーのような一般的なＣａＯ−ＳｉＯ2系フラックスを精錬剤として用い、この精錬剤中の硫黄含有量及び溶銑中の硫黄含有量を高めても、脱銅反応はほとんど起こらなかった。この要因について本発明者らは考察を重ねた結果、塩基性フラックスを用いてスラグ中のＣｕ2Ｓの活量を低下させる必要があることを知見した。そこで、Ｃｕ2Ｓの活量を低下させるべく、製鋼工程で一般的に用いられるＣａＯ系フラックスの添加を試みた。しかしながら、ＣａＯ系フラックスを添加した場合、スラグが固化してしまい脱銅反応を促進することはできなかった。そこで、ＣａＯ系フラックスよりも低融点で且つ強塩基性であるアルカリ金属の化合物を添加することを想起し、ＣａＯと同様に製鋼工程で一般的に用いられているＮａ2ＣＯ3（ソーダ灰）を用いて試験した。その結果、スラグの液相が確保でき、脱銅反応が促進されることを確認した。 Next, (2) and (3) will be described. Even if the general CaO-SiO 2 flux such as mold powder used in continuous casting machines is used as a refining agent and the sulfur content in the refining agent and the sulfur content in the hot metal are increased, the copper removal reaction Hardly happened. As a result of repeated investigations on this factor, the present inventors have found that it is necessary to reduce the activity of Cu 2 S in the slag using a basic flux. Therefore, in order to reduce the activity of Cu 2 S, an attempt was made to add a CaO-based flux that is generally used in the steel making process. However, when a CaO-based flux was added, the slag solidified and the copper removal reaction could not be promoted. Therefore, recalling the addition of an alkali metal compound having a lower melting point and stronger basicity than the CaO-based flux, Na 2 CO 3 (soda ash) generally used in the steelmaking process as with CaO. Were used to test. As a result, it was confirmed that a liquid phase of slag could be secured and the copper removal reaction was promoted.
この場合、添加したＮａ2ＣＯ3は、鉄−硫黄合金と反応してＮａ2Ｓを形成し、精錬剤が溶融して形成されるスラグ（「脱銅スラグ」とも記す）中では、Ｎａ2Ｓの形態で存在している。つまり、溶銑中の銅は、Ｎａ2ＳとＦｅＳとを主成分とする脱銅スラグにＣｕ2Ｓとして吸収されて、溶銑の脱銅反応が進行しており、効率的な脱銅反応のためには、脱銅スラグ中にＮａ2Ｓが、モル分率比で０．２以上存在することが好ましいことが知見された。つまり、アルカリ金属の硫化物を、脱銅スラグ中にモル分率比で０．２以上存在させることが重要であることが知見された。 In this case, the added Na 2 CO 3 reacts with the iron-sulfur alloy to form Na 2 S, and in the slag formed by melting the refining agent (also referred to as “decopper slag”), Na 2 It exists in the form of S. In other words, the copper in the hot metal is absorbed as Cu 2 S in the copper removal slag containing Na 2 S and FeS as main components, and the copper removal reaction of the hot metal proceeds, for efficient copper removal reaction. It was found that Na 2 S is preferably present in the copper removal slag at a molar fraction ratio of 0.2 or more. In other words, it has been found that it is important for the alkali metal sulfide to be present in the decopper slag at a molar fraction ratio of 0.2 or more.
しかしながら、ナトリウム（Ｎａ）は蒸気圧が高く、添加したＮａ2ＣＯ3が揮発ロスすることから、脱銅スラグ中にＮａ2Ｓをモル分率比で０．２以上存在させるためには、ソーダ灰などのＮａ2ＣＯ3を主成分とする材料を大量に添加する必要があった。 However, sodium (Na) has a high vapor pressure and volatilization loss of the added Na 2 CO 3 , so in order for Na 2 S to be present in the decopperized slag at a molar fraction ratio of 0.2 or more, soda It was necessary to add a large amount of a material mainly composed of Na 2 CO 3 such as ash.
そこで、このＮａ2ＣＯ3の揮発ロスを少なくすることを検討した。その結果、ナトリウムとの親和力が極めて強い、フッ素（Ｆ）、塩素（Ｃｌ）、臭素（Ｂｒ）などのハロゲン化物（ハロゲンが陰性元素として、より陽性の元素と化合した化合物）を精錬剤に加えることで、ナトリウムの蒸気圧が低下し、Ｎａ2ＣＯ3の揮発ロスが大幅に減少し、少ないＮａ2ＣＯ3で脱銅スラグ中にＮａ2Ｓをモル分率比で０．２以上確保できることが分かった。つまり、Ｎａ2ＣＯ3中のナトリウムは一旦ＮａＦ、ＮａＣｌ、ＮａＢｒなどのハロゲン化物となり、その後、大量に存在する鉄−硫黄合金と反応してＮａ2Ｓが形成される。一旦、ＮａＦ、ＮａＣｌ、ＮａＢｒなどの化合物となることで、ナトリウムの揮発ロスが抑制される。 Therefore, it was studied to reduce the volatilization loss of Na 2 CO 3 . As a result, halides such as fluorine (F), chlorine (Cl), and bromine (Br) (compounds that combine with a more positive element as a negative element) are added to the refining agent. As a result, the vapor pressure of sodium is reduced, the volatilization loss of Na 2 CO 3 is greatly reduced, and Na 2 S can be secured in a decopperized slag with a small Na 2 CO 3 in a molar fraction ratio of 0.2 or more. I understood. That is, sodium in Na 2 CO 3 once becomes a halide such as NaF, NaCl, and NaBr, and then reacts with a large amount of iron-sulfur alloy to form Na 2 S. Once it becomes a compound such as NaF, NaCl, or NaBr, sodium volatilization loss is suppressed.
この現象は、ナトリウム以外のアルカリ金属、例えば、カリウム（Ｋ）やリチウム（Ｌｉ）の化合物を硫黄含有フラックスの構成成分として使用した場合も、同様であることが分かった。つまり、カリウムやリチウムは、ナトリウムと同様に蒸気圧が高いが、フッ素、塩素、臭素などのハロゲンとの親和力が強く、一旦ハロゲン化物を形成することにより、揮発ロスが抑制される。 This phenomenon was found to be the same when an alkali metal other than sodium, for example, a compound of potassium (K) or lithium (Li) was used as a component of the sulfur-containing flux. That is, potassium and lithium have a high vapor pressure like sodium, but have strong affinity with halogens such as fluorine, chlorine and bromine, and once the halide is formed, volatilization loss is suppressed.
即ち、本発明においては、溶銑中の銅を分離除去するための精錬剤（以下、「脱銅用精錬剤」とも記す）として、アルカリ金属の化合物と、鉄−硫黄合金と、ハロゲン化物とを使用し、これらをそれぞれ単体のまま、または混合して銅含有溶銑に添加し、脱銅処理を実施する。 That is, in the present invention, an alkali metal compound, an iron-sulfur alloy, and a halide are used as a refining agent for separating and removing copper in the hot metal (hereinafter also referred to as “refining agent for copper removal”). These are used alone or mixed and added to the copper-containing hot metal to carry out the copper removal treatment.
本発明において使用するアルカリ金属の化合物としては、リチウム、ナトリウム、カルシウムのそれぞれ酸化物、炭酸塩、硫化物などを使用できるが、経済性の観点から、Ｎａ2ＣＯ3（ソーダ灰）またはＫ2ＣＯ3、或いは両者の混合物を使用することが好ましい。 As the alkali metal compound used in the present invention, oxides, carbonates, sulfides, etc. of lithium, sodium, and calcium can be used. From the viewpoint of economy, Na 2 CO 3 (soda ash) or K 2 It is preferable to use CO 3 or a mixture of both.
本発明において、Ｎａ2ＣＯ3やＫ2ＣＯ3などのアルカリ金属化合物の揮発ロスを少なくするために使用可能なハロゲン化物としては、例えば、塩化カリウム（ＫＣｌ）、弗化カリウム（ＫＦ）、塩化ナトリウム（ＮａＣｌ）、弗化ナトリウム（ＮａＦ）、弗化マグネシウム（ＭｇＦ2）、弗化カルシウム（ＣａＦ2）、氷晶石（Ｎａ3ＡｌＦ6）などである。 In the present invention, examples of halides that can be used to reduce volatilization loss of alkali metal compounds such as Na 2 CO 3 and K 2 CO 3 include potassium chloride (KCl), potassium fluoride (KF), and chloride. Sodium (NaCl), sodium fluoride (NaF), magnesium fluoride (MgF 2 ), calcium fluoride (CaF 2 ), cryolite (Na 3 AlF 6 ) and the like.
これらのハロゲン化物を、アルカリ金属の化合物または鉄−硫黄合金、或いは、アルカリ金属の化合物及び鉄−硫黄合金の双方と予め混合して、溶銑に添加することで、より一層アルカリ金属化合物の揮発ロスは少なくなることが分かった。 These halides are mixed in advance with an alkali metal compound or an iron-sulfur alloy, or both an alkali metal compound and an iron-sulfur alloy, and added to the hot metal to further reduce the volatilization loss of the alkali metal compound. Was found to be less.
尚、本発明者らは、アルカリ金属の化合物と鉄−硫黄合金とを予め混合してから溶銑に添加することで、より一層の脱銅効率の向上が望めることを確認しており、ハロゲン化物を除いて、アルカリ金属の化合物と鉄−硫黄合金との２つを予め混合しても構わない。また、脱銅用精錬剤のうちの鉄−硫黄合金のみを先に溶銑に添加し、溶銑中の硫黄濃度を高めた後に、ハロゲン化物及びアルカリ金属の化合物を、それぞれ単体で或いは混合して溶銑に添加することでも、十分に効率の良い脱銅処理を得ることができる。 In addition, the present inventors have confirmed that a further improvement in copper removal efficiency can be expected by adding an alkali metal compound and an iron-sulfur alloy in advance to the hot metal, and the halide is expected. Except for, two of an alkali metal compound and an iron-sulfur alloy may be mixed in advance. Also, only the iron-sulfur alloy of the copper removal refining agent is first added to the hot metal to increase the sulfur concentration in the hot metal, and then the halide and alkali metal compounds are used alone or mixed to form the hot metal. Also by adding to, a sufficiently efficient copper removal treatment can be obtained.
この硫黄を含有した脱銅用精錬剤による脱銅は、分配比（脱銅スラグ中のＣｕ濃度と溶銑中のＣｕ濃度との比）の低いプロセスであるため、脱銅を十分に進行させるには、前記精錬剤の添加により反応容器内に形成される脱銅スラグ側の物質移動を促進させる必要がある。このためには、脱銅スラグ層も撹拌することが重要である。特に、本発明では溶銑段階で脱銅処理しており、溶銑の温度域（１２００〜１４００℃）は溶鋼の温度域（１５５０〜１７００℃）に比較して低温であり、スラグの流動性も低く、スラグの撹拌が重要である。 Since copper removal using this sulfur-containing refining agent for copper removal is a process with a low distribution ratio (ratio of Cu concentration in the copper removal slag and Cu concentration in the hot metal), the copper removal is sufficiently advanced. It is necessary to promote the mass transfer on the side of the copper removal slag formed in the reaction vessel by the addition of the refining agent. For this purpose, it is important to stir the copper removal slag layer. In particular, in the present invention, the copper removal treatment is performed in the hot metal stage, the hot metal temperature range (1200 to 1400 ° C.) is lower than the molten steel temperature range (1550 to 1700 ° C.), and the slag fluidity is also low. Slag agitation is important.
溶銑及び溶銑上に存在するスラグを同時に攪拌する方法として、反応容器内の溶銑に浸漬させたインジェクションランスまたは反応容器の底部に設置した羽口から、攪拌用ガスを吹き込んでスラグと溶銑とを攪拌する方法も採り得るが、本発明においては、良好な攪拌が得られることから、機械攪拌式精錬装置を用いて脱銅処理を行うことが好ましい。機械攪拌式精錬装置としては、インペラ（「攪拌羽根」ともいう）を使用した撹拌が代表的である。つまり、取鍋状の反応容器内に収容された溶銑にインペラを浸漬させ、このインペラを、軸心を回転軸として回転させ、溶銑及び溶銑上に添加された脱銅用精錬剤を強制的に攪拌する方法である。機械攪拌式精錬装置では、溶銑上に投入された脱銅用精錬剤が溶銑内に充分に巻き込まれ、溶銑と脱銅用精錬剤との撹拌が充分に行われる。一方、特許文献１に示されたガス撹拌法では、スラグは溶銑中に巻き込まれ難く、撹拌は不充分である。 As a method of simultaneously stirring the hot metal and the slag present on the hot metal, stirring gas is blown from an injection lance immersed in the hot metal in the reaction vessel or a tuyere installed at the bottom of the reaction vessel to stir the slag and hot metal. However, in the present invention, it is preferable to perform a copper removal treatment using a mechanical stirring type refining apparatus because good stirring can be obtained. As a mechanical stirring type refining apparatus, stirring using an impeller (also referred to as “stirring blade”) is typical. In other words, the impeller is immersed in the hot metal contained in a ladle-shaped reaction vessel, and the impeller is rotated about the axis of rotation to forcibly remove the copper refining agent added on the hot metal and hot metal. It is a method of stirring. In the mechanical stirring type refining apparatus, the copper removal refining agent charged on the hot metal is sufficiently entrained in the hot metal, and the hot metal and the copper removal refining agent are sufficiently stirred. On the other hand, in the gas stirring method disclosed in Patent Document 1, the slag is not easily caught in the hot metal, and stirring is insufficient.
また、溶銑に浸漬させたインジェクションランスから搬送用ガスとともに粉体状の脱銅用精錬剤を溶銑中に吹き込み添加する方法、所謂フラックス吹き込み法も好ましい処理方法である。この場合、溶銑中に吹き込まれた粉体状の脱銅精錬剤は溶銑と直接接触し、しかも、新たな未反応の脱銅用精錬剤が連続的に溶銑と接触するので、スラグ側の物質移動を促進させた場合と同等の効果が発現し、溶銑と脱銅用精錬剤との反応が促進される。また、搬送用ガスは攪拌用ガスとしても機能するので、機械攪拌式精錬装置ほどの攪拌強度はないものの、溶銑と溶銑上の脱銅スラグとの攪拌が行われる。 Further, a method in which a powdered copper refining agent is blown into the molten iron from the injection lance immersed in the molten iron and so-called flux blowing is also a preferable treatment method. In this case, the powdered copper removal refining agent blown into the hot metal is in direct contact with the hot metal, and new unreacted copper removal refining agent is in continuous contact with the hot metal, so that the slag side material The effect equivalent to the case where the movement is promoted is exhibited, and the reaction between the hot metal and the copper refining agent is promoted. Further, since the carrier gas also functions as a stirring gas, the stirring of the hot metal and the copper removal slag on the hot metal is performed although the stirring strength is not as high as that of the mechanical stirring type refining apparatus.
この脱銅処理の際、雰囲気への大気の混入を防ぐために、Ａｒガスなどの不活性ガスやプロパンなどの還元性ガスを溶銑浴面上に供給してもよい。脱銅処理後、脱銅用精錬剤の添加により形成された脱銅スラグを系外に除去する。 In the copper removal treatment, an inert gas such as Ar gas or a reducing gas such as propane may be supplied onto the hot metal bath surface in order to prevent air from entering the atmosphere. After the copper removal treatment, the copper removal slag formed by addition of the copper removal refining agent is removed from the system.
本発明において、脱銅処理前の溶銑、つまり、銅含有鋼屑を加炭溶解して製造される、炭素を含有する製鋼用溶銑の温度は、１２００℃以上１５００℃以下、望ましくは１２５０℃以上１４００℃以下であることが好ましい。溶銑温度が１２００℃未満では、低温に起因する脱銅用精錬剤及び溶銑自体の固化・凝固が懸念される。特に、その後の脱硫工程や転炉脱炭工程での温度保証を考慮すると、１２５０℃以上とすることが望ましい。一方、１５００℃以上では、高温による脱銅用精錬剤の蒸発が無視できない。つまり、脱銅用精錬剤の蒸発を抑えて効率的に脱銅反応を行うには、溶銑温度は低いほど好ましく、従って、効率的な脱銅反応のためには、溶銑温度を１４００℃以下とすることが望ましい。 In the present invention, the temperature of the hot metal before copper removal treatment, that is, the temperature of the hot metal for steelmaking containing carbon produced by carburizing and melting copper-containing steel scrap is 1200 ° C. or higher and 1500 ° C. or lower, preferably 1250 ° C. or higher. It is preferable that it is 1400 degrees C or less. If the hot metal temperature is less than 1200 ° C., there is a concern that the refining agent for copper removal and the hot metal itself solidify and solidify due to the low temperature. In particular, considering the temperature guarantee in the subsequent desulfurization process and converter decarburization process, it is desirable to set the temperature to 1250 ° C. or higher. On the other hand, at 1500 ° C. or higher, evaporation of the decopper refining agent due to high temperature cannot be ignored. In other words, the hot metal temperature is preferably as low as possible in order to efficiently perform the copper removal reaction while suppressing the evaporation of the decoppering refining agent. Therefore, the hot metal temperature is set to 1400 ° C. or lower for efficient copper removal reaction. It is desirable to do.
また、脱銅処理前の溶銑中の炭素濃度は２質量％以上が好ましい。溶銑中の銅が硫化銅（Ｃｕ2Ｓ）となる反応は、熱力学的に溶銑中の炭素濃度が高いほど進行しやすいことが知られている。脱銅処理前の溶銑中の炭素濃度が２質量％未満では、硫化銅の生成反応が充分に起こらないことに加え、溶銑の液相線温度が上昇し、溶銑の容器壁への付着などが問題となる。また更に、脱銅処理前の溶銑中の銅濃度は０．１質量％以上１．０質量％以下であることが好ましい。脱銅処理前の溶銑中の銅濃度が１．０質量％を超えると銅の除去に必要な脱銅用精錬剤の量が過大となり、実用上の負荷が大きい。一方、０．１質量％未満の場合には、脱銅処理を施さなくても、例えば、銅含有量の低い溶銑で希釈するなどして対処可能である。 The carbon concentration in the hot metal before the copper removal treatment is preferably 2% by mass or more. It is known that the reaction in which the copper in the hot metal becomes copper sulfide (Cu 2 S) proceeds more thermodynamically as the carbon concentration in the hot metal becomes higher. If the carbon concentration in the hot metal before the copper removal treatment is less than 2% by mass, the formation reaction of copper sulfide does not occur sufficiently, the liquidus temperature of the hot metal rises, and the hot metal adheres to the vessel wall. It becomes a problem. Furthermore, the copper concentration in the hot metal before the copper removal treatment is preferably 0.1% by mass or more and 1.0% by mass or less. When the copper concentration in the hot metal before the copper removal treatment exceeds 1.0% by mass, the amount of the refining agent for copper removal necessary for removing copper is excessive, and the practical load is large. On the other hand, when it is less than 0.1% by mass, it can be dealt with by, for example, diluting with a hot metal having a low copper content without performing a copper removal treatment.
更に、脱銅処理前の溶銑の硫黄濃度としては、０．０１質量％以上が好ましく、０．０５質量％以上が更に好ましい。脱銅処理前の溶銑の硫黄濃度が０．０１質量％未満では、脱銅用精錬剤から溶銑中への硫黄の溶解量が過大となり、脱銅用精錬剤の利用効率が低くなり経済的でない。硫黄濃度の上限は特に規定する必要はないが、余りに高濃度であると脱硫処理に支障を来すので、０．５質量％以下とすることが望ましい。 Furthermore, the sulfur concentration of the hot metal before the copper removal treatment is preferably 0.01% by mass or more, and more preferably 0.05% by mass or more. If the concentration of sulfur in the hot metal before the copper removal treatment is less than 0.01% by mass, the amount of sulfur dissolved in the hot metal from the copper removal refining agent becomes excessive, and the use efficiency of the copper removal refining agent becomes low and it is not economical. . The upper limit of the sulfur concentration does not need to be specified in particular, but if it is too high, the desulfurization treatment will be hindered, so it is preferable to set it to 0.5 mass% or less.
脱銅処理前の上記以外の溶銑の成分としては、例えば珪素濃度は０．５質量％以下、マンガン濃度は０．５質量％以下が望ましい。これらの濃度を超えると、脱銅処理中のこれら成分の酸化により生じる酸化珪素及び酸化マンガンがスラグに移行してスラグ量が増大し、スラグ処理が困難になるだけでなく、酸化珪素及び酸化マンガンが脱銅用精錬剤の脱銅反応を阻害する恐れがある。 As the hot metal components other than those described above before the copper removal treatment, for example, the silicon concentration is preferably 0.5% by mass or less and the manganese concentration is preferably 0.5% by mass or less. When these concentrations are exceeded, silicon oxide and manganese oxide generated by oxidation of these components during the copper removal treatment are transferred to slag to increase the amount of slag, making slag treatment difficult, as well as silicon oxide and manganese oxide. May inhibit the copper removal reaction of the copper removal refining agent.
尚、銅含有鋼屑を加炭溶解して製造した製鋼用溶銑に、必要に応じて高炉から出銑された溶銑（以下、「高炉溶銑」と呼ぶ）を混合して銅濃度を希釈し、その後、混合した溶銑に含まれる銅を、脱銅用精錬剤を用いて除去するようにしてもよい。 In addition, the hot metal for steelmaking manufactured by carburizing and melting copper-containing steel scrap is mixed with hot metal discharged from the blast furnace (hereinafter referred to as “blast furnace hot metal”) as necessary to dilute the copper concentration. Then, you may make it remove the copper contained in the mixed hot metal using the refining agent for copper removal.
銅含有鋼屑を加炭溶解して溶銑を製造する工程としては、電気炉を用いた方法、転炉を用いた方法、竪型炉を用いた方法などがあるが、特に、内部に炭材ベッドを形成した竪型炉を用いた方法が好ましい。 As a process for producing hot metal by carburizing and dissolving copper-containing steel scrap, there are a method using an electric furnace, a method using a converter, a method using a vertical furnace, etc. A method using a vertical furnace in which a bed is formed is preferable.
ここで、内部に炭材ベッドを形成した竪型炉とは、竪型炉の上部から銅含有鋼屑及びコークス更には必要に応じて造滓剤を装入し、竪型炉の下部に設けた羽口から、空気、酸素富化空気、酸素ガス、熱風などを送風してコークスを燃焼させ、コークスの燃焼熱によって銅含有鋼屑及び造滓剤を溶解し、炉底部の出湯口から溶銑及び溶融スラグを取り出す装置である。この場合、炉底から羽口の上方或る高さ位置までの範囲にはコークスだけを詰め、これを燃焼してコークスの上部に装入した銅含有鋼屑を溶解している。炉底に詰めるコークスを「炭材ベッド」と呼び、この炭材ベッドは燃焼して消耗するので、これを補いながら溶解を継続するために、炉体の上部からコークスを装入する。銅含有鋼屑が溶解して生成される溶融鉄は、コークスの間隙を流下し、コークスにより加炭されて溶銑が生成される。この内部に炭材ベッドを形成した竪型炉は、電気炉などに比較してエネルギー効率が高いことが知られている。 Here, a vertical furnace with a charcoal bed formed inside is a steel containing copper-containing steel scraps and coke from the upper part of the vertical furnace and, if necessary, a slagging agent, and is provided at the lower part of the vertical furnace. The coke is burned by blowing air, oxygen-enriched air, oxygen gas, hot air, etc. from the heated tuyere, and the copper-containing steel scrap and iron making agent are melted by the combustion heat of the coke, and the hot metal is melted from the tap at the bottom of the furnace. And an apparatus for taking out molten slag. In this case, only the coke is packed in the range from the furnace bottom to a certain height above the tuyere, and this is burned to melt the copper-containing steel scrap charged in the upper part of the coke. The coke that fills the bottom of the furnace is called a “charcoal bed”, and the charcoal bed burns and wears out. To compensate for this, the coke is charged from the top of the furnace body. The molten iron produced by melting the copper-containing steel scraps flows down the coke gap and is carburized by the coke to produce hot metal. It is known that a vertical furnace having a charcoal bed formed therein has higher energy efficiency than an electric furnace or the like.
このような、内部に炭材ベッドを形成した竪型炉を用いて溶銑を製造する場合、高炉溶銑に比して溶銑中の硫黄濃度は一般的に高くなる。この硫黄濃度の高い状態を利用して、脱銅用精錬剤による脱銅を有利に進めることができる。溶銑中の硫黄濃度が高いことにより、脱銅用精錬剤から溶銑中への硫黄の移動が少なくて済み、脱銅用精錬剤の利用効率を高めることができる。 When hot metal is produced using such a vertical furnace in which a carbon material bed is formed, the sulfur concentration in the hot metal is generally higher than that in the blast furnace hot metal. Taking advantage of this high sulfur concentration, copper removal with a copper removal refining agent can be advantageously promoted. Since the sulfur concentration in the hot metal is high, there is little movement of sulfur from the decopper refining agent into the hot metal, and the utilization efficiency of the decopper refining agent can be increased.
このような脱銅処理に伴い、脱銅用精錬剤中の硫黄が不可避的に溶銑中に移行するため、溶銑中の硫黄濃度は上昇する。従って、脱銅処理を行った後、溶銑中の硫黄を除去する処理を行う。この脱硫処理は、公知の機械攪拌式精錬装置による方法、ランスからの粉体吹き込みによる方法、転炉を使用する方法などの何れであってもよい。脱硫剤としては、ＣａＯを主成分とする脱硫剤、カルシウム・カーバイドを主成分とする脱硫剤、ソーダ灰を主成分とする脱硫剤、金属Ｍｇなど種々の脱硫剤を使用することができる。 Along with such copper removal treatment, sulfur in the copper removal refining agent inevitably moves into the hot metal, so the sulfur concentration in the hot metal increases. Therefore, after performing a copper removal treatment, a treatment for removing sulfur in the hot metal is performed. This desulfurization treatment may be any of a method using a known mechanical stirring type refining device, a method by blowing powder from a lance, a method using a converter, and the like. As the desulfurization agent, various desulfurization agents such as a desulfurization agent mainly composed of CaO, a desulfurization agent mainly composed of calcium carbide, a desulfurization agent mainly composed of soda ash, and metallic Mg can be used.
この脱硫処理に先立ち、脱銅処理に供した脱銅用精錬剤を反応容器から除去することが必要である。脱銅用精錬剤を除去しないまま、脱硫処理すると、脱銅用精錬剤中の硫化銅（Ｃｕ2Ｓ）が分解して溶銑に戻り、溶銑中の銅濃度が上昇する恐れがあるからである。スラグ除去作業は、公知のスラグドラッガーを用いた方法、スラグ吸引機による方法、溶銑収容容器を傾けて容器内のスラグを排出する方法などの何れでもよく、各製鉄所の保有する設備状況に適したものを選択すればよい。 Prior to this desulfurization treatment, it is necessary to remove the decopper refining agent used for the decopperization treatment from the reaction vessel. If the desulfurization treatment is performed without removing the copper removal refining agent, the copper sulfide (Cu 2 S) in the copper removal refining agent is decomposed and returned to the hot metal, which may increase the copper concentration in the hot metal. . The slag removal operation may be any of a method using a known slag dragger, a method using a slag suction machine, a method of discharging the slag in the container by inclining the hot metal container, and is suitable for the equipment situation possessed by each steelworks You can select the one you want.
以上説明したように、本発明によれば、銅を含有する溶銑中の銅を分離・除去するための脱銅用精錬剤として、Ｎａ2ＣＯ3などのアルカリ金属の化合物と、鉄−硫黄合金と、ハロゲン化物とを使用するので、添加されるハロゲン化物とアルカリ金属化合物中のアルカリ金属とでアルカリ金属のハロゲン化物が形成され、これによりアルカリ金属の蒸気圧が低下し、アルカリ金属化合物の蒸発ロスが減少し、少ないアルカリ金属化合物で効率良く溶銑を脱銅処理することが実現される。その結果、銅含有鋼屑から銅含有量の少ない溶銑を効率良く得ることが可能となる。 As described above, according to the present invention, an alkaline metal compound such as Na 2 CO 3 and an iron-sulfur alloy are used as a copper removal refining agent for separating and removing copper in the hot metal containing copper. And a halide, an alkali metal halide is formed by the added halide and the alkali metal in the alkali metal compound, thereby reducing the vapor pressure of the alkali metal and evaporating the alkali metal compound. Loss is reduced, and it is possible to efficiently remove copper from the hot metal with a small alkali metal compound. As a result, it is possible to efficiently obtain hot metal having a small copper content from the copper-containing steel scrap.
高周波誘導溶解炉を用いて、黒鉛ルツボ中で銅を０．４質量％、硫黄を０．３％含有する炭素飽和溶銑を調製した。この溶銑に、ソーダ灰（Ｎａ2ＣＯ3）または炭酸カリウム（Ｋ2ＣＯ3）、鉄−硫黄合金（フェロサルファー、硫黄含有量：４８質量％）及びハロゲン化物を脱銅用精錬剤として添加し、溶銑に脱銅処理を施す試験を実施した（試験Ｎo.１〜６）。また、比較のために、ハロゲン化物を添加しないで、ソーダ灰または炭酸カリウムと、鉄−硫黄合金とを脱銅用精錬剤として添加する脱銅試験も実施した（試験Ｎo.７〜８）。ソーダ灰または炭酸カリウムと、鉄−硫黄合金と、ハロゲン化物とは予め混合して脱銅用精錬剤とした。 Using a high frequency induction melting furnace, a carbon saturated hot metal containing 0.4% by mass of copper and 0.3% of sulfur was prepared in a graphite crucible. To this hot metal, soda ash (Na 2 CO 3 ) or potassium carbonate (K 2 CO 3 ), an iron-sulfur alloy (ferrosulfur, sulfur content: 48 mass%) and a halide are added as a refining agent for copper removal. A test for removing copper from the hot metal was carried out (Test Nos. 1 to 6). For comparison, a copper removal test was also performed in which soda ash or potassium carbonate and an iron-sulfur alloy were added as a copper refining agent without adding a halide (Test Nos. 7 to 8). Soda ash or potassium carbonate, iron-sulfur alloy, and halide were mixed in advance to obtain a refining agent for copper removal.
表１に、試験条件及び試験結果を一覧で示す。尚、何れの実験も溶銑温度は１３５０℃に調整した。 Table 1 shows a list of test conditions and test results. In all experiments, the hot metal temperature was adjusted to 1350 ° C.
表１に示すように、脱銅用精錬剤にハロゲン化物を加えた試験Ｎo.１〜６では、脱銅率が何れも３３％以上であり、ハロゲン化物を加えていない試験Ｎo.７，８に比べて効率良く脱銅処理することができた。 As shown in Table 1, in test Nos. 1 to 6 in which halides were added to a copper refining agent, the copper removal rate was 33% or more, and test Nos. 7 and 8 in which no halide was added. Compared to the above, it was possible to remove copper efficiently.
これらの結果から、本発明によれば高い脱銅率が得られ、銅含有溶銑から銅含有量の低い溶銑を効率的に製造できることが確認できた。 From these results, it was confirmed that according to the present invention, a high copper removal rate was obtained, and it was possible to efficiently produce hot metal having a low copper content from copper-containing hot metal.
内部に炭材ベッドを形成した竪型炉を用いて、銅含有鋼屑を溶解して製鋼用溶銑を製造し、この溶銑を溶銑鍋で受銑し、溶銑鍋内の溶銑に、ソーダ灰（Ｎａ2ＣＯ3）、鉄−硫黄合金（フェロサルファー、硫黄含有量：４８質量％）及びハロゲン化物を脱銅用精錬剤として添加し、溶銑に脱銅処理を施す試験を実施した（試験Ｎo.９〜１０）。ハロゲン化物として、試験Ｎo.９ではＮａＦ、試験Ｎo.１０では氷晶石（主な化学組成Ｎａ3ＡｌＦ6）を使用した。また、比較のために、ハロゲン化物を使用しないで、ソーダ灰及び鉄−硫黄合金のみを脱銅用精錬剤として添加する脱銅試験も実施した（試験Ｎo.１１）。ソーダ灰、鉄−硫黄合金及びハロゲン化物は予め混合して脱銅用精錬剤とした。 Using a vertical furnace with a charcoal bed formed inside, copper-containing steel scrap is melted to produce hot metal for steelmaking. This hot metal is received in the hot metal ladle, and soda ash ( Na 2 CO 3 ), an iron-sulfur alloy (ferrosulfur, sulfur content: 48% by mass) and a halide were added as a refining agent for copper removal, and a test for removing copper from the hot metal was carried out (Test No. 9-10). As the halide, NaF was used in Test No. 9 and cryolite (main chemical composition Na 3 AlF 6 ) was used in Test No. 10. In addition, for comparison, a copper removal test was performed in which only soda ash and an iron-sulfur alloy were added as a refining agent for copper removal without using a halide (Test No. 11). Soda ash, iron-sulfur alloy and halide were mixed in advance to obtain a refining agent for copper removal.
脱銅処理は、試験Ｎo.９〜１１ともに、溶銑鍋に約５トンの製鋼用溶銑を装入し、機械攪拌式精錬装置において、鍋上に設けた精錬剤供給用ホッパーから脱銅用精錬剤を添加し、耐火物で被覆したインペラを溶銑中に浸漬させ、インペラを回転して溶銑及び脱銅用精錬剤を攪拌して行った。脱銅用精錬剤の添加量は、ソーダ灰（Ｎａ2ＣＯ3）を溶銑トンあたり２５ｋｇ、鉄−硫黄合金を溶銑トンあたり３７ｋｇ、ハロゲン化物は、ＮａＦを溶銑トンあたり４．５ｋｇまたは氷晶石を溶銑トンあたり３．４ｋｇとした。 In both tests No. 9 to 11, the copper removal treatment was carried out by charging the hot metal ladle with about 5 tons of steelmaking hot metal and using a mechanical stirring type refining device to refining for copper removal from the smelting agent supply hopper provided on the pan. Then, the impeller coated with the refractory was immersed in the hot metal, and the impeller was rotated to stir the hot metal and the copper refining agent. The addition amount of the refining agent for copper removal is 25 kg of hot soda ash (Na 2 CO 3 ) per ton of hot metal, 37 kg of iron-sulfur alloy per ton of hot metal, and the halide is 4.5 kg of hot metal per ton of hot metal or cryolite. Was 3.4 kg per ton of hot metal.
表２に、試験条件及び試験結果を一覧で示す。表２に記載以外の脱銅処理前の溶銑成分は、珪素が０．２０質量％、マンガンが０．１５質量％、燐が０．０５０質量％になるように調製して試験した。 Table 2 lists the test conditions and test results. The hot metal components before copper removal treatment other than those described in Table 2 were prepared and tested so that silicon was 0.20 mass%, manganese was 0.15 mass%, and phosphorus was 0.050 mass%.
表２に示すように、脱銅用精錬剤にハロゲン化物としてＮａＦまたは氷晶石を加えた試験Ｎo.９〜１０では、ハロゲン化物を加えていない試験Ｎo.１１に比べて、脱銅率が高位であった。 As shown in Table 2, in the test No. 9 to 10 in which NaF or cryolite was added as a halide to the copper refining agent, the copper removal rate was higher than that in the test No. 11 in which no halide was added. It was high.
これらの結果から、本発明によれば高い脱銅率が得られ、銅含有鋼屑から銅含有量の低い溶銑を効率的に製造できることが確認できた。 From these results, it was confirmed that according to the present invention, a high copper removal rate was obtained, and it was possible to efficiently produce hot metal having a low copper content from copper-containing steel scrap.
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