JP2014201805A - Method for regenerating desulfurization slag and method for converting desulfurization slag to useful material - Google Patents
Method for regenerating desulfurization slag and method for converting desulfurization slag to useful material Download PDFInfo
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- 239000002893 slag Substances 0.000 title claims abstract description 161
- 238000006477 desulfuration reaction Methods 0.000 title claims abstract description 114
- 230000023556 desulfurization Effects 0.000 title claims abstract description 114
- 238000000034 method Methods 0.000 title claims abstract description 31
- 230000001172 regenerating effect Effects 0.000 title claims abstract description 6
- 239000000463 material Substances 0.000 title claims description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 105
- 229910052742 iron Inorganic materials 0.000 claims abstract description 45
- 238000010438 heat treatment Methods 0.000 claims abstract description 38
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 35
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 35
- 239000011593 sulfur Substances 0.000 claims abstract description 35
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 12
- 239000001301 oxygen Substances 0.000 claims abstract description 12
- 239000002245 particle Substances 0.000 claims abstract description 11
- 239000007789 gas Substances 0.000 claims abstract description 7
- 239000002184 metal Substances 0.000 claims description 48
- 229910052751 metal Inorganic materials 0.000 claims description 48
- 238000006243 chemical reaction Methods 0.000 claims description 20
- 239000003795 chemical substances by application Substances 0.000 claims description 19
- 239000000446 fuel Substances 0.000 claims description 7
- 238000011069 regeneration method Methods 0.000 claims description 6
- 230000008929 regeneration Effects 0.000 claims description 4
- WETINTNJFLGREW-UHFFFAOYSA-N calcium;iron;tetrahydrate Chemical compound O.O.O.O.[Ca].[Fe].[Fe] WETINTNJFLGREW-UHFFFAOYSA-N 0.000 abstract description 12
- 229910000805 Pig iron Inorganic materials 0.000 abstract 1
- 230000001276 controlling effect Effects 0.000 abstract 1
- 230000001105 regulatory effect Effects 0.000 abstract 1
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 43
- 239000000292 calcium oxide Substances 0.000 description 37
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 32
- 239000011575 calcium Substances 0.000 description 18
- 230000008569 process Effects 0.000 description 12
- 238000000926 separation method Methods 0.000 description 10
- 229910052791 calcium Inorganic materials 0.000 description 8
- 230000003009 desulfurizing effect Effects 0.000 description 8
- 238000009628 steelmaking Methods 0.000 description 7
- 238000012360 testing method Methods 0.000 description 7
- 235000012255 calcium oxide Nutrition 0.000 description 5
- 238000002844 melting Methods 0.000 description 5
- 239000002904 solvent Substances 0.000 description 5
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 4
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
- 238000007670 refining Methods 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000002485 combustion reaction Methods 0.000 description 3
- 238000010907 mechanical stirring Methods 0.000 description 3
- 238000003672 processing method Methods 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 2
- 229910004261 CaF 2 Inorganic materials 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 2
- 238000003723 Smelting Methods 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 229910000019 calcium carbonate Inorganic materials 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 229910001882 dioxygen Inorganic materials 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 238000011835 investigation Methods 0.000 description 2
- 238000007885 magnetic separation Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 239000005997 Calcium carbide Substances 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-N Sulfurous acid Chemical compound OS(O)=O LSNNMFCWUKXFEE-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000005261 decarburization Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 230000012447 hatching Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 238000004513 sizing Methods 0.000 description 1
- 235000017550 sodium carbonate Nutrition 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 239000000126 substance Substances 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
- 229910000859 α-Fe Inorganic materials 0.000 description 1
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Abstract
Description
本発明は、溶銑の脱硫処理で発生した、ＣａＯを主成分とする脱硫スラグから、この脱硫スラグに含有される硫黄を除去して脱硫スラグを再生する方法に関し、また、硫黄を除去した後の脱硫スラグを製鋼工程でＣａＯ源として有効活用する利材化方法に関する。 The present invention relates to a method for regenerating desulfurized slag by removing sulfur contained in the desulfurized slag from a desulfurized slag containing CaO as a main component generated by the desulfurization treatment of hot metal, and after removing the sulfur. The present invention relates to a material utilization method for effectively utilizing desulfurized slag as a CaO source in a steelmaking process.
鉄鋼製品の材料特性の向上及び品質要求の高まりを受け、溶銑の脱硫処理が溶銑における予備精錬として各製鉄所で行われている。この脱硫処理においては、溶銑中の硫黄（Ｓ）は、一般的に、酸化カルシウム（ＣａＯ）を主成分とするフラックス（脱硫剤）の添加、並びに、このフラックスと溶銑との撹拌処理により、硫化物形態となってスラグへ除去されている。尚、溶銑の脱硫処理とは、転炉にて脱炭精錬する前の溶銑段階で溶銑中の硫黄を除去する処理のことであり、また、この脱硫処理後に生成するスラグを「脱硫スラグ」と称している。 In response to the improvement in material properties and the quality requirements of steel products, hot metal desulfurization treatment is carried out at each steelworks as preliminary refining in hot metal. In this desulfurization treatment, sulfur (S) in hot metal is generally sulfided by adding a flux (desulfurization agent) mainly composed of calcium oxide (CaO) and stirring the flux with hot metal. It has been removed to slag as a physical form. The hot metal desulfurization treatment is a treatment for removing sulfur in the hot metal at the hot metal stage before decarburization and refining in the converter. Also, the slag generated after this desulfurization treatment is called “desulfurization slag”. It is called.
溶銑の脱硫処理比率の上昇に伴って、脱硫スラグの発生量が増加している。上記のように、脱硫スラグには硫黄が含まれており、水の存在する環境下で脱硫スラグを再利用すると硫黄（黄水）が溶出し、環境に悪影響を与える懸念があり、発生量が増加している脱硫スラグの利材化には大きな制約のあるのが実体である。また、溶銑の脱硫処理におけるＣａＯの脱硫剤としての利用効率は高々数％程度であり、溶銑の脱硫処理で使用されるＣａＯの大部分は、未利用のまま脱硫スラグとして製鉄所外へ排出されている。 The amount of desulfurized slag generated is increasing with the increase in the desulfurization ratio of hot metal. As mentioned above, desulfurized slag contains sulfur, and if desulfurized slag is reused in an environment where water is present, sulfur (yellow water) may be eluted, which may adversely affect the environment, and the amount generated In reality, there are substantial restrictions on the increasing use of desulfurized slag. In addition, the utilization efficiency of CaO as a desulfurizing agent in hot metal desulfurization is at most several percent, and most of the CaO used in hot metal desulfurization is discharged outside the steelworks as desulfurized slag. ing.
そこで、これらの課題を解決するべく以下のような技術が提案されている。 In order to solve these problems, the following techniques have been proposed.
例えば、特許文献１には、硫黄及びカルシウム（Ｃａ）を含有する鉄鋼スラグを溶媒に浸漬し、該溶媒中に二酸化炭素を吹き込み、且つ溶媒をｐＨ４〜１０に調整することで、鉄鋼スラグに含まれる硫黄成分とＣａ成分とを溶媒中に抽出するとともに、抽出されたＣａ成分を前記二酸化炭素と反応させて炭酸カルシウムを生成させ、該炭酸カルシウムを処理済スラグとともに回収する硫黄・Ｃａ含有スラグの処理方法が開示されている。
For example, in Patent Document 1, steel slag containing sulfur and calcium (Ca) is immersed in a solvent, carbon dioxide is blown into the solvent, and the solvent is adjusted to
特許文献２には、脱硫スラグを大気中で１１００〜１４００℃に加熱処理し、この加熱処理により、「ＣａＳ＋ｘＣＯ／ＣＯ2→ＣａＯ＋ＳＯ2＋ｘＣ」の反応を利用して、脱硫スラグ中の硫黄を亜硫酸ガスとして脱硫スラグから除去するとともに、加熱処理で生成した溶湯と酸化物とを分離・回収する脱硫スラグの処理方法が開示されている。
In
特許文献３には、炉長と炉内径との比が５以下のロータリーキルンの上流開口端から、塩基度を０．８〜１．４に調整した平均粒子径が０．０２〜５ｍｍのスラグを装入するとともに、該スラグの還元当量の１．５〜４倍の還元剤を装入し、前記上流開口端から加熱用バーナーにより下流開口端に向けて燃焼火炎を放射し、ロータリーキルン内の処理物の温度を１２５０〜１４５０℃に調整してスラグを還元し、溶融スラグ及びメタルを得るスラグの溶融還元方法において、ロータリーキルンの下流開口端に、水平に対して１０〜４５°下向きの方向を向いた、ダムリングの生成を防止または抑制するためのバーナーを設置し、燃料に対する空気比を０．９〜１．５に調整して前記ロータリーキルン内を加熱するスラグの溶融還元方法が開示されている。 In Patent Document 3, a slag having an average particle diameter of 0.02 to 5 mm with a basicity adjusted to 0.8 to 1.4 from the upstream opening end of a rotary kiln having a ratio of the furnace length to the furnace inner diameter of 5 or less. In addition to charging, a reducing agent 1.5 to 4 times the reduction equivalent of the slag is charged, a combustion flame is emitted from the upstream opening end toward the downstream opening end by a heating burner, and processing in the rotary kiln In the slag smelting and reducing method for reducing the slag by adjusting the temperature of the product to 1250 to 1450 ° C. to obtain molten slag and metal, the downstream opening end of the rotary kiln is directed downward by 10 to 45 ° with respect to the horizontal. Disclosed is a slag smelting reduction method in which a burner for preventing or suppressing the generation of a dam ring is installed, the air ratio to fuel is adjusted to 0.9 to 1.5, and the inside of the rotary kiln is heated. It has been.
尚、「ダムリング」とは、完全に溶融していないスラグや浸炭が不十分で高融点のメタルがロータリーキルンの内壁に部分的に付着・堆積して形成されるリング状の堆積物、或いは、一旦溶融した処理物が冷却され、流動性が低下するためにロータリーキルンの内壁に部分的に付着し、この付着物が成長して堆積して形成されるリング状の堆積物であり、傾斜したロータリーキルン内を流れる溶融物や移動する反応生成物などが、あたかもダム（堰）が設置されたかのように堰き止められることから、「ダムリング」と称している。このダムリングの形成は、ロータリーキルンのような回転加熱型の反応炉では操業上の大きな問題となる。 The “dam ring” is a ring-shaped deposit formed by partially adhering and depositing slag or carburization that is not completely melted and a high melting point metal partially attached to the inner wall of the rotary kiln, or The slanted rotary kiln is a ring-shaped deposit that is formed by depositing a part of the inner surface of the rotary kiln that has been melted and deposited because the melted product is cooled and fluidity is lowered. It is called “dam ring” because melts flowing inside and moving reaction products are blocked as if a dam (weir) was installed. The formation of the dam ring is a major operational problem in a rotary heating reactor such as a rotary kiln.
しかしながら、上記従来技術には以下の問題がある。 However, the above prior art has the following problems.
即ち、特許文献１は湿式処理であり、湿式処理の場合、処理に必要な薬品が高価であるのみならず、大掛かりな処理設備が必要となり、設備費及び運転費ともに高価となる。 That is, Patent Document 1 is a wet process, and in the case of a wet process, not only the chemicals necessary for the process are expensive, but also a large-scale processing facility is required, and both the equipment cost and the operating cost are expensive.
特許文献２に開示された温度域においては、脱硫スラグは金属鉄を含有することから、スラグ中の金属鉄が酸化され、生成する酸化鉄がスラグ中のＣａＯと反応することで低融点のカルシウムフェライトが生成する。これが未溶融固体との混合物として処理容器内に付着し、ダムリングが発生する。ダムリングの発生は操業を大きく阻害する原因となることから、脱硫スラグの大規模処理の上で大きな問題となる。つまり、特許文献２は、ダムリングの発生を防止する対策が採られていないという問題がある。
In the temperature range disclosed in
特許文献３は、塩基度を０．８〜１．４に調整する必要があり、特許文献３を、ＣａＯを主成分とする脱硫スラグに適用する場合には、塩基度調整のためのＳｉＯ2源が必要となる。また、特許文献３では、ダムリングは生成しないものの、ダムリング解消用のバーナーを余分に設置することから、ランニングコストの上昇に繋がり、また、水平に対して１０〜４５°下向きのバーナーを設置しており、このバーナーによって炉体耐火物が直接炙られることから、耐火物の溶損にも繋がる。 In Patent Document 3, it is necessary to adjust the basicity to 0.8 to 1.4, and when Patent Document 3 is applied to desulfurized slag containing CaO as a main component, SiO 2 for adjusting the basicity. A source is needed. Further, in Patent Document 3, although a dam ring is not generated, an extra burner for eliminating the dam ring is installed, which leads to an increase in running cost, and a burner that is 10 to 45 ° downward with respect to the horizontal is installed. Since the furnace refractory is directly burned by this burner, it also leads to melting of the refractory.
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、溶銑の脱硫処理で発生する脱硫スラグを回転加熱型の反応炉で加熱処理し、この加熱処理で脱硫スラグに含有される硫黄を除去するにあたり、ダムリング解消用のバーナーを余分に設置することなく、カルシウムフェライトに起因するダムリングを発生させずに、安定的な加熱処理を連続して行うことのできる脱硫スラグの再生処理方法を提供することであり、また、硫黄を除去した後の脱硫スラグを製鋼工程でＣａＯ源として有効活用する利材化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 the object of the present invention is to heat-treat desulfurization slag generated by hot metal desulfurization treatment in a rotary heating reactor, and to contain the desulfurization slag by this heat treatment. Of desulfurized slag that can be continuously subjected to stable heat treatment without generating extra dam ring burners and without generating dam rings due to calcium ferrite. It is to provide a regeneration treatment method, and to provide a material utilization method for effectively utilizing desulfurized slag after removing sulfur as a CaO source in a steelmaking process.
上記課題を解決するための本発明の要旨は以下のとおりである。
［１］溶銑の脱硫処理で発生した、ＣａＯを主成分とする脱硫スラグを回転加熱型の反応炉に装入し、前記反応炉に設けられた燃料バーナーにより、前記反応炉の炉内雰囲気の温度を１０００〜１４００℃に制御するとともに、炉内雰囲気の酸素分圧をＰO2（atm）としたときＰO2が−８≦logＰO2≦−４となるように制御して反応炉内の前記脱硫スラグを加熱処理し、該加熱処理によって前記脱硫スラグ中の硫黄成分をＳＯｘとして気相側へ除去して脱硫スラグを再生する、脱硫スラグの再生処理方法であって、前記脱硫スラグは、その粒径が５ｍｍ以下になるように、前記反応炉に装入する前に予め整粒されており、且つ、前記脱硫スラグは、脱硫スラグ中に混入している金属鉄を除去するための処理が、前記反応炉に装入する前に予め施されていることを特徴とする、脱硫スラグの再生処理方法。
［２］反応炉に装入する脱硫スラグ中の金属鉄の含有量と、反応炉の炉内雰囲気の温度とが、反応炉に装入する脱硫スラグ中のＣａＯの含有量に対して、下記の（１）式の関係を満足するように、装入する脱硫スラグの金属鉄の含有量及び／または炉内雰囲気の温度とすることを特徴とする、上記［１］に記載の脱硫スラグの再生処理方法。
(質量％M-Fe)＜［ａ−(40/56)×(質量％CaO)］/(Ｔ−ｂ) …(1)
但し、（１）式において、（質量％Ｍ-Ｆｅ）は、脱硫スラグ中の金属鉄の含有量（質量％）、（質量％ＣａＯ）は、脱硫スラグ中のＣａＯの含有量（質量％）、Ｔは、反応炉の炉内雰囲気の温度（℃）である。また、ａ及びｂは、反応炉の炉内雰囲気の温度によって決まる定数である。
［３］上記［１］または上記［２］に記載の脱硫スラグの再生処理方法によって脱硫スラグ中の硫黄成分が除去された後の脱硫スラグを、溶銑の脱硫処理の脱硫剤として使用することを特徴とする、脱硫スラグの利材化方法。
The gist of the present invention for solving the above problems is as follows.
[1] The desulfurization slag containing CaO as a main component generated in the hot metal desulfurization treatment is charged into a rotary heating type reaction furnace, and a fuel burner provided in the reaction furnace allows the atmosphere in the furnace of the reaction furnace to be reduced. While controlling the temperature to 1000 to 1400 ° C. and controlling the oxygen partial pressure in the furnace atmosphere to P O2 (atm), P O2 is controlled to satisfy −8 ≦ log P O2 ≦ −4. A desulfurization slag regeneration treatment method in which desulfurization slag is heat treated, and sulfur component in the desulfurization slag is removed as SOx to the gas phase side by the heat treatment to regenerate the desulfurization slag. The particle size is adjusted to be 5 mm or less in advance before charging into the reactor, and the desulfurized slag is treated to remove metallic iron mixed in the desulfurized slag. Before charging into the reactor. Is characterized in that is, the reproduction processing method of desulfurization slag.
[2] The content of metallic iron in the desulfurization slag charged into the reaction furnace and the temperature in the furnace atmosphere of the reaction furnace are as follows with respect to the content of CaO in the desulfurization slag charged into the reaction furnace: The desulfurized slag as set forth in [1] above, wherein the content of metallic iron in the desulfurized slag to be charged and / or the temperature in the furnace atmosphere is set so as to satisfy the relationship of the formula (1). Playback processing method.
(Mass% M-Fe) <[a- (40/56) × (mass% CaO)] / (Tb) (1)
However, in the formula (1), (mass% M-Fe) is the content (% by mass) of metallic iron in the desulfurized slag, and (mass% CaO) is the content (mass%) of CaO in the desulfurized slag. , T is the temperature (° C.) of the atmosphere inside the reactor. Further, a and b are constants determined by the temperature of the atmosphere in the reactor.
[3] Use of the desulfurized slag after the sulfur component in the desulfurized slag has been removed by the desulfurized slag regeneration method described in [1] or [2] above as a desulfurizing agent for the desulfurization treatment of hot metal. A method for making desulfurized slag into a useful material.
本発明によれば、溶銑の脱硫処理で発生する脱硫スラグを製鋼工程へリサイクルするにあたり、先ず、例えば気流分離法や磁力分離法によって脱硫スラグから事前に金属鉄を除去し、その後、回転加熱型の反応炉を用いて、脱硫スラグ中の硫黄を気相側へＳＯｘとして除去する加熱処理を脱硫スラグに施すので、炉内雰囲気の温度及び酸素ポテンシャルを調整して行う加熱処理では、カルシウムフェライトに起因するダムリングの発生を防止することができ、連続した安定的な加熱処理が可能となり、ランニングコストの削減が達成される。また、硫黄成分が除去された後の脱硫スラグを、溶銑の脱硫処理での投射用脱硫剤としてリサイクルするので、脱硫スラグの発生量を大幅に少なくすることが可能となり、溶銑の脱硫処理コストを、従来に比較して大幅に低減することが実現される。 According to the present invention, when recycling the desulfurized slag generated in the hot metal desulfurization process to the steelmaking process, first, for example, the metallic iron is removed from the desulfurized slag in advance by an air flow separation method or a magnetic force separation method, and then the rotary heating type Is used to remove sulfur in the desulfurized slag as SOx to the gas phase side, and the desulfurized slag is subjected to heat treatment by adjusting the temperature and oxygen potential of the furnace atmosphere. Occurrence of the dam ring caused can be prevented, continuous and stable heat treatment can be performed, and the running cost can be reduced. In addition, since the desulfurized slag after the sulfur component is removed is recycled as a projection desulfurizing agent in the hot metal desulfurization process, the amount of desulfurized slag generated can be greatly reduced, and the desulfurization cost of the hot metal is reduced. Thus, it is possible to achieve a significant reduction compared to the prior art.
以下、本発明を詳細に説明する。 Hereinafter, the present invention will be described in detail.
本発明者らは、ＣａＯ単体、或いは、ＣａＯにＣａＦ2またはＡｌ2Ｏ3をＣａＯの滓化促進剤とて添加したＣａＯ−ＣａＦ2やＣａＯ−Ａｌ2Ｏ3などのＣａＯを主成分（ＣａＯ含有量５０質量％以上）とする脱硫剤を用いた溶銑の脱硫処理で発生する脱硫スラグを、製鋼工程、主に溶銑脱硫工程の脱硫剤用のＣａＯ源としてリサイクルするにあたり、リサイクル使用する前に、脱硫スラグから脱硫スラグ中の硫黄成分を除去する方法を検討した。 The present inventors have used CaO alone or CaO such as CaO—CaF 2 or CaO—Al 2 O 3 in which CaF 2 or Al 2 O 3 is added to CaO as a CaO hatching accelerator (CaO). Before recycling the desulfurization slag generated in the hot metal desulfurization process using a desulfurizing agent with a content of 50% by mass or more) as a CaO source for the desulfurizing agent in the steelmaking process, mainly in the hot metal desulfurization process Then, a method for removing sulfur components in desulfurized slag from desulfurized slag was examined.
具体的には、バーナー加熱タイプの回転加熱型の反応炉（「ロータリーキルン」ともいう）を反応容器として使用し、脱硫スラグからの硫黄除去条件について実験・調査を行った。その結果、図１に示すように、反応炉内の雰囲気温度を１０００〜１５００℃の範囲として脱硫スラグに加熱処理を施し、且つ、そのときの炉内雰囲気の酸素分圧（ＰO2（atm））を−８≦logＰO2≦−４に保つことで、脱硫スラグからの硫黄成分の除去が効率的に行われることが確認された。尚、ここで、反応炉内の雰囲気温度とは、炉内で最も低温となる、キルン出側の雰囲気温度である。 Specifically, a burner heating type rotary heating reactor (also referred to as “rotary kiln”) was used as a reaction vessel, and experiments and investigations were conducted on the conditions for removing sulfur from desulfurized slag. As a result, as shown in FIG. 1, the desulfurization slag was heated with the atmospheric temperature in the reactor in the range of 1000 to 1500 ° C., and the oxygen partial pressure (P O2 (atm)) in the furnace atmosphere at that time ) Is maintained at −8 ≦ log P O2 ≦ −4, it has been confirmed that the removal of the sulfur component from the desulfurized slag is performed efficiently. Here, the atmospheric temperature in the reaction furnace is the atmospheric temperature on the exit side of the kiln that is the lowest temperature in the furnace.
上記回転加熱型の反応炉では、炉内をバーナーで加熱しており、バーナー用燃料と、この燃料の燃焼用酸素ガスとの混合比率を調整することで、炉内雰囲気の酸素分圧（ＰO2（atm））を容易に調整することができる。つまり、供給する燃焼用酸素ガスを、供給するバーナー用燃料の当量に対して少なくすれば、炉内の酸素分圧（ＰO2（atm））は低下する。また、脱硫スラグからの硫黄除去反応を効率的に行うために、加熱処理する脱硫スラグの粒径（直径）は５ｍｍ以下とすることが必要である。脱硫スラグの粒径は篩によって特定されるものであり、従って、目開き寸法が５ｍｍの篩を通過する限り、長径が５ｍｍを超える紡錘形の粒子が混入しても構わない。 In the rotary heating type reactor, the inside of the furnace is heated by a burner, and the oxygen partial pressure (P) in the furnace atmosphere is adjusted by adjusting the mixing ratio of the fuel for the burner and the oxygen gas for combustion of this fuel. O2 (atm)) can be adjusted easily. That is, if the combustion oxygen gas supplied is reduced relative to the equivalent of the burner fuel supplied, the oxygen partial pressure (P O2 (atm)) in the furnace decreases. Further, in order to efficiently perform the sulfur removal reaction from the desulfurized slag, the particle size (diameter) of the desulfurized slag to be heat-treated needs to be 5 mm or less. The particle size of the desulfurized slag is specified by the sieve. Therefore, spindle-shaped particles having a major axis exceeding 5 mm may be mixed as long as it passes through a sieve having an opening size of 5 mm.
しかしながら、事前に金属鉄が分離・除去されていない脱硫スラグを１０００〜１４００℃の範囲で加熱処理すると、加熱処理によって生成する溶融物と装入した未溶融固体との混合物が炉壁に付着し、ダムリングが生成する場合が発生した。ダムリングが生成する場合には、操業が阻害され、安定した加熱処理はできなかった。また、雰囲気温度が１４００℃を超えると、雰囲気温度が高いために、事前の金属鉄の分離・除去に拘わらず、脱硫スラグが半溶融状態となってダムリングが発生した。このことから、反応炉内の雰囲気温度は１０００〜１４００℃の範囲に制御する必要のあることがわかった。 However, if desulfurized slag from which metallic iron has not been separated and removed in advance is heat-treated at a temperature in the range of 1000 to 1400 ° C., a mixture of the melt produced by the heat treatment and the charged unmelted solid adheres to the furnace wall. When a dam ring is generated, it occurs. When dam rings were formed, the operation was hindered and stable heat treatment was not possible. Further, when the ambient temperature exceeded 1400 ° C., the ambient temperature was high, so that the desulphurized slag was in a semi-molten state and dam ring was generated regardless of the prior separation and removal of metallic iron. From this, it was found that the atmospheric temperature in the reactor must be controlled in the range of 1000 to 1400 ° C.
一般的に、ＣａＯを主成分とする脱硫剤は、機械攪拌式脱硫装置での溶銑の脱硫処理で使用されている。これは、ＣａＯを主成分とする脱硫剤は、金属Ｍｇ、カルシウムカーバイド、ソーダ灰などの他の脱硫剤に比較して脱硫能が低いことから、機械攪拌式脱硫装置を用いて溶銑と脱硫剤とを強攪拌させ、脱硫反応を促進させることが必要であるからである。従って、溶銑と脱硫剤とを強攪拌させることから、ＣａＯを主成分とする脱硫剤を用いた溶銑の脱硫処理後に生成する脱硫スラグには、多くの金属鉄が混入する。 In general, a desulfurization agent containing CaO as a main component is used in the desulfurization treatment of hot metal in a mechanical stirring desulfurization apparatus. This is because the desulfurization agent mainly composed of CaO has a lower desulfurization ability than other desulfurization agents such as metal Mg, calcium carbide, and soda ash. This is because it is necessary to vigorously stir and accelerate the desulfurization reaction. Therefore, since the hot metal and the desulfurization agent are vigorously stirred, a large amount of metallic iron is mixed in the desulfurization slag generated after the desulfurization treatment of the hot metal using the desulfurization agent mainly composed of CaO.
事前に金属鉄の除去処理を施さずに加熱処理して、脱硫スラグからの硫黄の除去を試みると、スラグ中の金属鉄が酸化され、生成する酸化鉄がスラグ中のＣａＯと反応することで低融点のカルシウムフェライトが生成する。特に、回転加熱型の反応炉においては、低融点のカルシウムフェライト融体の生成はダムリング発生の原因となることから、脱硫スラグに事前に除鉄処理を施す必要のあることが判明した。 If you try to remove sulfur from desulfurized slag by heat treatment without removing metallic iron in advance, the metallic iron in the slag is oxidized, and the iron oxide that is produced reacts with CaO in the slag. Low melting calcium ferrite is formed. In particular, in a rotary heating type reactor, the formation of a low-melting calcium ferrite melt causes dam ring generation, and it has been found that it is necessary to subject the desulfurized slag to iron removal in advance.
そこで、カルシウムフェライトが生成されない条件を熱力学的に検討した。その結果、脱硫スラグに対する雰囲気温度が１０００〜１４００℃の範囲では、反応温度に応じて、脱硫スラグ中の金属鉄の含有量とスラグ中のＣａＯの含有量とを調整することで、カルシウムフェライトの生成が抑制できることがわかった。 Therefore, the conditions under which calcium ferrite was not generated were studied thermodynamically. As a result, in the range where the atmospheric temperature for desulfurized slag is 1000 to 1400 ° C., by adjusting the content of metallic iron in the desulfurized slag and the content of CaO in the slag according to the reaction temperature, It was found that the production can be suppressed.
更に、脱硫スラグ中の金属鉄の含有量とスラグ中のＣａＯの含有量とをどのように調整すれば、カルシウムフェライトの生成が抑制できるかを確認するために、バーナー加熱タイプの回転加熱型の反応炉を用い、脱硫スラグ中の金属鉄の含有量及び雰囲気温度を変更し、ダムリング発生の有無を調査する試験を行った。図２に、試験結果を示す。 Furthermore, in order to confirm whether the production of calcium ferrite can be suppressed by adjusting the content of metallic iron in the desulfurized slag and the content of CaO in the slag, the rotation heating type of the burner heating type Using a reaction furnace, the content of metallic iron in desulfurized slag and the atmospheric temperature were changed, and a test was conducted to investigate the presence or absence of dam ring generation. FIG. 2 shows the test results.
図２において、横軸は、脱硫スラグ中のＣａ含有量（質量％）と金属鉄含有量（質量％）との和に対する脱硫スラグ中の金属鉄含有量（質量％）の比率であり、縦軸は、雰囲気温度であり、また、符号「○」はダムリングが発生しない試験、符号「□」はダムリングが発生した試験、符号「●」は脱硫不良の試験である。図２の符号「□」で示した条件のうち、１４００℃以上の条件では、雰囲気温度が高いために脱硫スラグが半溶融状態となってダムリングが発生し、１０００〜１４００℃の条件では、カルシウムフェライトが生成したためにダムリングが発生した。 In FIG. 2, the horizontal axis represents the ratio of the metal iron content (mass%) in the desulfurized slag to the sum of the Ca content (mass%) and the metal iron content (mass%) in the desulfurized slag, and the vertical axis The axis is the ambient temperature, the symbol “◯” is a test in which no dam ring is generated, the symbol “□” is a test in which a dam ring is generated, and the symbol “●” is a test for defective desulfurization. Among the conditions indicated by the symbol “□” in FIG. 2, under the condition of 1400 ° C. or higher, the atmosphere temperature is high, so the desulfurized slag is in a semi-molten state and dam ring is generated, and under the condition of 1000 to 1400 ° C., Damring occurred due to the formation of calcium ferrite.
また、図２における折れ線の境界線は、１０００℃の雰囲気温度を基点として雰囲気温度を１００℃単位として熱力学的検討のもとに定めたダムリング発生の有無の境界線である。つまり、雰囲気温度が１０００〜１４００℃の範囲において、横軸の金属鉄含有量の比率に対して、境界線よりも上側の雰囲気温度ではダムリングが発生せず、境界線よりも下側の雰囲気温度ではダムリングが発生することを意味している。図２から明らかなように、雰囲気温度が高くなるほど、脱硫スラグ中の金属鉄含有量の比率が高くなってもダムリングが発生しないことがわかる。 Further, the boundary line of the broken line in FIG. 2 is a boundary line indicating whether or not a dam ring is generated, which is determined based on thermodynamic investigation with an atmospheric temperature of 100 ° C. as a base point and an atmospheric temperature of 1000 ° C. That is, when the ambient temperature is in the range of 1000 to 1400 ° C., the dam ring does not occur at the ambient temperature above the boundary line with respect to the ratio of the metallic iron content on the horizontal axis, and the atmosphere below the boundary line It means that dam ring occurs at temperature. As is clear from FIG. 2, it can be seen that dam rings do not occur as the ambient temperature increases even if the ratio of the content of metallic iron in the desulfurized slag increases.
図２に示す、ダムリング有無の境界線は、下記の（２）式で表される。
Ｔ＝ａ×(質量％M-Fe)/[(質量％M-Fe)＋(質量％Ca)]＋ｂ …(2)
但し、（２）式において、Ｔは雰囲気温度（℃）、つまり、反応炉の炉内雰囲気温度（℃）であり、（質量％Ｍ-Ｆｅ）は、脱硫スラグ中の金属鉄含有量（質量％）、（質量％Ｃａ）は、脱硫スラグ中のＣａ含有量（質量％）である。また、ａ及びｂは定数であり、定数ａ及び定数ｂは、下記の（３）式の平衡定数に脱硫スラグ処理時の炉内雰囲気の酸素分圧の最大値（logＰO2=−４（atm））を適用し、Ｃａ、Ｆｅの比を規定することで、各温度域において下記の表１に示す値として求めることができる。
2Ca＋2Fe＋5/2O2→Ca2Fe2O5 …(3)
The boundary line with or without dam ring shown in FIG. 2 is expressed by the following equation (2).
T = a × (mass% M-Fe) / [(mass% M-Fe) + (mass% Ca)] + b (2)
However, in the formula (2), T is the atmospheric temperature (° C.), that is, the atmospheric temperature (° C.) in the reactor, and (mass% M-Fe) is the content of metal iron (mass by mass) in the desulfurized slag. %) And (mass% Ca) are Ca contents (mass%) in the desulfurized slag. Further, a and b are constants, and the constants a and b are the maximum values of the oxygen partial pressure in the furnace atmosphere during the desulfurization slag treatment (log P O2 = −4 (atm )) And by defining the ratio of Ca and Fe, the values shown in Table 1 below can be obtained in each temperature range.
2Ca + 2Fe + 5 / 2O 2 → Ca 2 Fe 2 O 5 (3)
（２）式の右辺以下の温度になると、Ｃａ2Ｆｅ2Ｏ5が生成する（３）式が進行することから、カルシウムフェライトが生成することが予想される。 When the temperature is equal to or lower than the right side of the formula (2), the formula (3) in which Ca 2 Fe 2 O 5 is generated proceeds, so that calcium ferrite is expected to be generated.
（２）式をＭ-Ｆｅについて整理し、％Ｃａを％ＣａＯに換算すると、ダムリングが発生しない条件として、下記の（１）式が得られる。
(質量％M-Fe)＜［ａ−(40/56)×(質量％CaO)］/(Ｔ−ｂ) …(1)
即ち、雰囲気温度（Ｔ）とスラグ中ＣａＯ濃度（質量％）とを（１）式に適用したときに算出される（質量％Ｍ-Ｆｅ）に対して、脱硫スラグ中の金属鉄含有量（質量％）が高ければカルシウムフェライトが生成するが、脱硫スラグ中の金属鉄含有量が算出される（質量％Ｍ-Ｆｅ）に対して低くなるように、事前に金属鉄除去処理を施せば、カルシウムフェライトが生成せず、ダムリングの発生を抑制することが可能となる。
When the formula (2) is arranged for M-Fe and% Ca is converted to% CaO, the following formula (1) is obtained as a condition that dam ring does not occur.
(Mass% M-Fe) <[a- (40/56) × (mass% CaO)] / (Tb) (1)
That is, with respect to (mass% M-Fe) calculated when the atmospheric temperature (T) and the CaO concentration (mass%) in the slag are applied to the formula (1), the content of metallic iron in the desulfurized slag ( (Mass%) is high, calcium ferrite is generated. However, if the metal iron removal treatment is performed in advance so that the metal iron content in the desulfurized slag is lower than the calculated (mass% M-Fe), Calcium ferrite is not generated, and dam ring generation can be suppressed.
本発明は、上記試験結果に基づきなされたもので、本発明に係る脱硫スラグの再生処理方法は、脱硫スラグを回転加熱型の反応炉に装入し、前記反応炉に設けられた燃料バーナーにより、反応炉の炉内雰囲気の温度を１０００〜１４００℃に制御するとともに炉内雰囲気の酸素分圧（ＰO2（atm））を−８≦logＰO2≦−４に制御して反応炉内に装入した脱硫スラグを加熱処理し、該加熱処理によって前記脱硫スラグ中の硫黄成分をＳＯｘとして気相側へ除去して脱硫スラグを再生する、脱硫スラグの再生処理方法であって、前記脱硫スラグは、その粒径が５ｍｍ以下になるように、前記反応炉に装入する前に予め整粒されており、且つ、前記脱硫スラグは、脱硫スラグ中に混入する金属鉄を除去するための処理が、前記反応炉に装入する前に予め施されていることを必須の条件とする。 The present invention was made on the basis of the above test results, and the desulfurization slag regeneration method according to the present invention was carried out by charging the desulfurization slag into a rotary heating reactor and using a fuel burner provided in the reactor. In addition, the temperature of the reactor atmosphere in the reactor is controlled to 1000 to 1400 ° C., and the oxygen partial pressure (P O2 (atm)) in the reactor atmosphere is controlled to −8 ≦ log P O2 ≦ −4. The desulfurization slag is reprocessed by heat-treating the desulfurization slag that has been added, and removing the sulfur component in the desulfurization slag as SOx to the gas phase side by the heat treatment to regenerate the desulfurization slag, The particle size of the desulfurized slag is preliminarily adjusted before being charged into the reactor so that the particle size thereof is 5 mm or less, and the desulfurized slag is subjected to a treatment for removing metallic iron mixed in the desulfurized slag. Before charging into the reactor The essential condition that has been subjected order.
脱硫スラグからの金属鉄の分離には、例えば磁力を用いた分離や、金属鉄とスラグとの比重差を利用した遠心気流分離などを用いることができる。金属鉄の分離を促進させる観点から、脱硫スラグを５ｍｍ以下の粒径に破砕・整粒した後、金属鉄の分離処理を行うことが好ましい。 For separation of metallic iron from desulfurized slag, for example, separation using magnetic force, centrifugal airflow separation using the specific gravity difference between metallic iron and slag, or the like can be used. From the viewpoint of promoting separation of metallic iron, it is preferable to perform separation treatment of metallic iron after crushing and sizing the desulfurized slag to a particle size of 5 mm or less.
硫黄成分を除去した後の脱硫スラグは、硫黄含有量の少ないＣａＯ源として製鋼工程で再利用することが可能であり、製鋼工程で再利用した場合には、脱硫スラグ自体の発生量が減少して脱硫スラグの処理コストを削減できるとともに、ＣａＯ系精錬用媒溶剤の削減にも繋がる。本発明者らは、溶銑脱硫時の投射設備の脱硫剤として、粉状の生石灰と遜色なく利用できることを確認している。 The desulfurized slag after removing the sulfur component can be reused in the steelmaking process as a CaO source with a low sulfur content. When reused in the steelmaking process, the amount of desulfurized slag itself is reduced. As a result, the processing cost of the desulfurization slag can be reduced and the CaO-based refining medium solvent can be reduced. The inventors of the present invention have confirmed that it can be used as powdered quicklime as a desulfurization agent for a projection facility during hot metal desulfurization.
以上説明したように、本発明によれば、溶銑の脱硫処理で発生する脱硫スラグを製鋼工程へリサイクルするにあたり、先ず、例えば気流分離法や磁力分離法によって脱硫スラグから事前に金属鉄を除去し、その後、回転加熱型の反応炉を用いて、脱硫スラグ中の硫黄を気相側へＳＯｘとして除去する加熱処理を脱硫スラグに施すので、この加熱処理ではカルシウムフェライトに起因するダムリングの発生を防止することができ、連続した安定的な加熱処理が可能となり、ランニングコストの削減が達成される。 As described above, according to the present invention, when recycling the desulfurization slag generated in the hot metal desulfurization process to the steelmaking process, first, metallic iron is removed from the desulfurization slag in advance by, for example, an air separation method or a magnetic separation method. Then, since heat treatment for removing sulfur in the desulfurized slag as SOx to the gas phase side is performed on the desulfurized slag using a rotary heating type reactor, the dam ring due to calcium ferrite is generated in this heat treatment. Can be prevented, continuous and stable heat treatment is possible, and a reduction in running cost is achieved.
高炉から出銑された高炉溶銑には０．０３質量％程度の硫黄が含有されており、溶銑脱硫工程において、脱硫剤としてＣａＯ源を添加し、機械攪拌式脱硫装置で撹拌処理することで、溶銑は、硫黄濃度が０．００３質量％程度にまで脱硫処理される。この脱硫処理で発生する脱硫スラグに対して、本発明を適用する試験を実施した。 The blast furnace hot metal discharged from the blast furnace contains about 0.03% by mass of sulfur, and in the hot metal desulfurization process, a CaO source is added as a desulfurizing agent, and the mixture is stirred with a mechanical stirring desulfurization apparatus. The hot metal is desulfurized to a sulfur concentration of about 0.003% by mass. The test which applies this invention was implemented with respect to the desulfurization slag generate | occur | produced by this desulfurization process.
脱硫処理で発生した脱硫スラグの代表組成を表２に示す。金属鉄を除去する前の脱硫スラグには、１０質量％程度の金属鉄が混入している。 Table 2 shows representative compositions of desulfurization slag generated by the desulfurization treatment. About 10% by mass of metal iron is mixed in the desulfurized slag before the metal iron is removed.
上記の脱硫スラグ５０トンを粒径５ｍｍ以下に破砕・整粒し、その後、遠心気流分離及び／または磁力分離による金属鉄の除去処理を施し、脱硫スラグ中の金属鉄含有量とＣａＯ含有量との比を変えた。このようにして得られた脱硫スラグを、加熱バーナーを備えたロータリーキルンに装入し、バーナーによって脱硫スラグを加熱して、脱硫スラグからの硫黄除去処理を実施した。 The above desulfurized slag 50 tons is crushed and sized to a particle size of 5 mm or less, and then subjected to a removal process of metallic iron by centrifugal airflow separation and / or magnetic separation, and the metallic iron content and CaO content in the desulfurized slag The ratio of was changed. The desulfurization slag thus obtained was charged into a rotary kiln equipped with a heating burner, and the desulfurization slag was heated by the burner to carry out a sulfur removal treatment from the desulfurization slag.
図１に、各雰囲気温度における炉内雰囲気酸素分圧（logＰO2（atm））と脱硫率との関係を示す。雰囲気温度が１０００℃よりも低い条件では硫黄成分の除去が十分でなく、１０００℃以上の条件においては、炉内雰囲気の酸素分圧が−８≦logＰO2≦−４を満たすときに８０％以上の高い脱硫率が得られた。 FIG. 1 shows the relationship between the in-furnace oxygen partial pressure (log P O2 (atm)) and the desulfurization rate at each ambient temperature. When the atmospheric temperature is lower than 1000 ° C., the sulfur component is not sufficiently removed. When the atmospheric temperature is 1000 ° C. or higher, 80% or higher when the oxygen partial pressure in the furnace atmosphere satisfies −8 ≦ log P O2 ≦ −4. A high desulfurization rate was obtained.
図２に、脱硫スラグ中のＣａ含有量（質量％Ｃａ）と脱硫スラグ中の金属鉄含有量（質量％Ｍ-Ｆｅ）との和に対する脱硫スラグ中の金属鉄含有量（質量％Ｍ-Ｆｅ）の比率と、雰囲気温度（Ｔ）との関係から、ダムリング発生の有無を調査した結果を示す。脱硫スラグ中の金属鉄含有量（質量％Ｍ-Ｆｅ）及び脱硫スラグ中のＣａ含有量（質量％Ｃａ）は分析して求めた値である。 FIG. 2 shows the metal iron content (mass% M-Fe) in the desulfurized slag with respect to the sum of the Ca content (mass% Ca) in the desulfurized slag and the metal iron content (mass% M-Fe) in the desulfurized slag. ) And the relationship between the ambient temperature (T) and the result of investigating the occurrence of dam ring. The metal iron content (mass% M-Fe) in the desulfurized slag and the Ca content (mass% Ca) in the desulfurized slag are values obtained by analysis.
図２の符号「○」で示した条件では、ダムリングが発生せず、脱硫率も８０％以上の結果が得られた。一方、図２の符号「●」で示した条件では、雰囲気温度が低く脱硫率が悪かった。また、図２の符号「□」で示した条件のうち、１４００℃以上の条件では、雰囲気温度が高いために脱硫スラグが半溶融状態となってダムリングが発生し、１０００〜１４００℃の条件では、カルシウムフェライトが生成したためにダムリングが発生し、何れも操業が阻害された。 Under the conditions indicated by the symbol “◯” in FIG. 2, no dam ring was generated, and a desulfurization rate of 80% or more was obtained. On the other hand, under the conditions indicated by the symbol “●” in FIG. 2, the ambient temperature was low and the desulfurization rate was poor. In addition, among the conditions indicated by the symbol “□” in FIG. 2, under the conditions of 1400 ° C. or higher, the atmosphere temperature is high, so the desulfurized slag is in a semi-molten state and dam rings are generated, and the conditions of 1000 to 1400 ° C. Then, dam ring was generated because calcium ferrite was generated, and the operation was hindered in all cases.
脱硫率が８０％以上の加熱処理後の脱硫スラグを投射設備の脱硫剤として用いて機械攪拌式脱硫装置で溶銑の脱硫処理を実施した。図３は、脱硫率が８０％以上の加熱処理後の脱硫スラグを脱硫剤として使用した場合と、粉状生石灰を脱硫剤として使用した場合とで、脱硫処理前の溶銑中硫黄濃度と脱硫処理後の溶銑中硫黄濃度との関係を比較して示す図である。 Desulfurization of hot metal was carried out with a mechanical stirring type desulfurization apparatus using desulfurized slag after heat treatment with a desulfurization rate of 80% or more as a desulfurization agent for the projection equipment. Figure 3 shows the sulfur concentration in the hot metal before the desulfurization treatment and the desulfurization treatment when desulfurization slag after heat treatment with a desulfurization rate of 80% or more is used as the desulfurization agent and when powdered quicklime is used as the desulfurization agent. It is a figure which compares and shows the relationship with the sulfur concentration in the hot metal after.
図３に示すように、脱硫率が８０％以上の加熱処理後の脱硫スラグを使用した脱硫処理では、粉状生石灰を使用した脱硫処理と同等の脱硫率が得られることがわかった。即ち、脱硫率が８０％以上の加熱処理後の脱硫スラグは、未使用の粉状生石灰と遜色なく精錬工程に適用できることが確認できた。 As shown in FIG. 3, it was found that the desulfurization treatment using the desulfurization slag after the heat treatment having a desulfurization rate of 80% or more can obtain a desulfurization rate equivalent to the desulfurization treatment using powdered quicklime. In other words, it was confirmed that the desulfurized slag after the heat treatment having a desulfurization rate of 80% or more can be applied to the refining process without inferior to unused powdered quicklime.
Claims (3)
前記脱硫スラグは、その粒径が５ｍｍ以下になるように、前記反応炉に装入する前に予め整粒されており、且つ、前記脱硫スラグは、脱硫スラグ中に混入している金属鉄を除去するための処理が、前記反応炉に装入する前に予め施されていることを特徴とする、脱硫スラグの再生処理方法。 The desulfurization slag containing CaO as a main component generated in the hot metal desulfurization treatment is charged into a rotary heating type reaction furnace, and the temperature of the atmosphere in the reaction furnace is set to 1000 by a fuel burner provided in the reaction furnace. The desulfurization slag in the reaction furnace is controlled by controlling so that P O2 is −8 ≦ log P O2 ≦ −4 when the oxygen partial pressure in the furnace atmosphere is P O2 (atm). A desulfurization slag regeneration treatment method for regenerating desulfurization slag by heat treatment, removing sulfur components in the desulfurization slag as SOx to the gas phase side by the heat treatment,
The desulfurization slag is pre-sized before being charged into the reactor so that the particle size thereof is 5 mm or less, and the desulfurization slag is made of metallic iron mixed in the desulfurization slag. A method for regenerating desulfurized slag, characterized in that the treatment for removal is performed in advance before charging the reactor.
(質量％M-Fe)＜［ａ−(40/56)×(質量％CaO)］/(Ｔ−ｂ) …(1)
但し、（１）式において、（質量％Ｍ-Ｆｅ）は、脱硫スラグ中の金属鉄の含有量（質量％）、（質量％ＣａＯ）は、脱硫スラグ中のＣａＯの含有量（質量％）、Ｔは、反応炉の炉内雰囲気の温度（℃）である。また、ａ及びｂは、反応炉の炉内雰囲気の温度によって決まる定数である。 The content of metallic iron in the desulfurization slag charged into the reaction furnace and the temperature of the furnace atmosphere of the reaction furnace are the following (1) with respect to the content of CaO in the desulfurization slag charged into the reaction furnace: The method for regenerating desulfurized slag according to claim 1, wherein the content of metallic iron in the desulfurized slag to be charged and / or the temperature of the atmosphere in the furnace is set so as to satisfy the relationship of formula (1).
(Mass% M-Fe) <[a- (40/56) × (mass% CaO)] / (Tb) (1)
However, in the formula (1), (mass% M-Fe) is the content (% by mass) of metallic iron in the desulfurized slag, and (mass% CaO) is the content (mass%) of CaO in the desulfurized slag. , T is the temperature (° C.) of the atmosphere inside the reactor. Further, a and b are constants determined by the temperature of the atmosphere in the reactor.
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| CN111285406A (en) * | 2020-02-14 | 2020-06-16 | 北京科技大学 | Method for co-recycling alumina red mud and semi-dry desulfurization ash |
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