JP7531274B2 - How to treat by-products - Google Patents
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- JP7531274B2 JP7531274B2 JP2019216822A JP2019216822A JP7531274B2 JP 7531274 B2 JP7531274 B2 JP 7531274B2 JP 2019216822 A JP2019216822 A JP 2019216822A JP 2019216822 A JP2019216822 A JP 2019216822A JP 7531274 B2 JP7531274 B2 JP 7531274B2
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- 239000006227 byproduct Substances 0.000 title claims description 105
- 229910052751 metal Inorganic materials 0.000 claims description 77
- 239000002184 metal Substances 0.000 claims description 77
- 239000002893 slag Substances 0.000 claims description 56
- 238000010438 heat treatment Methods 0.000 claims description 47
- 239000000428 dust Substances 0.000 claims description 46
- 239000000203 mixture Substances 0.000 claims description 32
- 238000000034 method Methods 0.000 claims description 28
- 239000000126 substance Substances 0.000 claims description 25
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 21
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 21
- 239000011819 refractory material Substances 0.000 claims description 21
- 229910052710 silicon Inorganic materials 0.000 claims description 21
- 239000010703 silicon Substances 0.000 claims description 21
- 239000010802 sludge Substances 0.000 claims description 17
- 239000010881 fly ash Substances 0.000 claims description 15
- 239000000463 material Substances 0.000 claims description 15
- 150000002739 metals Chemical class 0.000 claims description 14
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 10
- 229910052681 coesite Inorganic materials 0.000 claims description 8
- 229910052906 cristobalite Inorganic materials 0.000 claims description 8
- 238000002156 mixing Methods 0.000 claims description 8
- 239000000377 silicon dioxide Substances 0.000 claims description 8
- 235000012239 silicon dioxide Nutrition 0.000 claims description 8
- 229910052682 stishovite Inorganic materials 0.000 claims description 8
- 229910052905 tridymite Inorganic materials 0.000 claims description 8
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 7
- 229910052799 carbon Inorganic materials 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 7
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 6
- 229910052593 corundum Inorganic materials 0.000 claims description 6
- 229910001845 yogo sapphire Inorganic materials 0.000 claims description 6
- 239000004576 sand Substances 0.000 claims description 5
- 239000002994 raw material Substances 0.000 description 28
- 230000000052 comparative effect Effects 0.000 description 25
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 12
- 238000000926 separation method Methods 0.000 description 11
- 239000003638 chemical reducing agent Substances 0.000 description 10
- 238000003672 processing method Methods 0.000 description 8
- 238000009628 steelmaking Methods 0.000 description 8
- 238000002844 melting Methods 0.000 description 7
- 230000008018 melting Effects 0.000 description 7
- 238000007670 refining Methods 0.000 description 7
- 239000011651 chromium Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 229910044991 metal oxide Inorganic materials 0.000 description 6
- 150000004706 metal oxides Chemical class 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 5
- 238000001816 cooling Methods 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 5
- 238000011109 contamination Methods 0.000 description 4
- 230000005611 electricity Effects 0.000 description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- 238000003723 Smelting Methods 0.000 description 3
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 239000010949 copper Substances 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 230000036571 hydration Effects 0.000 description 3
- 238000006703 hydration reaction Methods 0.000 description 3
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 3
- 239000000155 melt Substances 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 238000007664 blowing Methods 0.000 description 2
- QDOXWKRWXJOMAK-UHFFFAOYSA-N dichromium trioxide Chemical compound O=[Cr]O[Cr]=O QDOXWKRWXJOMAK-UHFFFAOYSA-N 0.000 description 2
- 238000010891 electric arc Methods 0.000 description 2
- AMWRITDGCCNYAT-UHFFFAOYSA-L hydroxy(oxo)manganese;manganese Chemical compound [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 238000004017 vitrification Methods 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- -1 SiO2 Chemical class 0.000 description 1
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 239000002956 ash Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 229910000423 chromium oxide Inorganic materials 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- VASIZKWUTCETSD-UHFFFAOYSA-N manganese(II) oxide Inorganic materials [Mn]=O VASIZKWUTCETSD-UHFFFAOYSA-N 0.000 description 1
- 238000006263 metalation reaction Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910000480 nickel oxide Inorganic materials 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000002407 reforming Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical group [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 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
- Processing Of Solid Wastes (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Description
本発明は、金属製造工程で発生する副生成物の処理方法に関する。 The present invention relates to a method for treating by-products generated during metal manufacturing processes.
金属精錬工程では、原料中の不純物を高温で金属分と分離するため、大量のスラグ、ダストが発生する。また、金属精錬工程では高温の金属、スラグを保持する容器が必要であり、これら容器に使用される耐火物は経時劣化に伴い廃棄され使用済み耐火物となる。さらに、金属精錬工程で製造された鉄鋼スラブや各種金属のインゴットを、製品へ加工するにあたり、適宜圧延、加工、表面処理等が行われるが、その際に使用された水、油には金属酸化物が含まれこれを分離したスラッジが発生する。その他に、石炭火力発電所等では燃料中の灰分が燃焼後に残り、フライアッシュとして回収されている。 In the metal refining process, large amounts of slag and dust are generated because impurities in the raw materials are separated from the metal at high temperatures. The metal refining process also requires containers to hold the hot metal and slag, and the refractories used in these containers deteriorate over time and are discarded, becoming used refractories. Furthermore, when the steel slabs and ingots of various metals produced in the metal refining process are processed into products, they are rolled, processed, surface treated, etc. as appropriate, and the water and oil used in this process contain metal oxides, which separate out to produce sludge. In addition, at coal-fired power plants, etc., the ash in the fuel remains after combustion and is collected as fly ash.
金属製造工程で発生するスラグ、ダスト、使用済み耐火物、スラッジ等の副生成物は、いずれもＳｉＯ２、Ａｌ２Ｏ３、ＣａＯ、ＭｇＯ等の金属酸化物を主成分としており、砕石やコンクリート原料として利用することが期待される。しかしながら、これらの副生成物は、その組成に応じて、例えば、ＣａＯやＭｇＯが多いものは経時的に膨張や粉化が生じたり、微小ながら金属成分が溶出する可能性のあるものがあり、有効利用できていないものも少なくなかった。 By-products such as slag, dust, used refractories, and sludge generated in metal manufacturing processes are all mainly composed of metal oxides such as SiO2 , Al2O3 , CaO, and MgO, and are expected to be used as crushed stone or concrete raw materials. However, depending on the composition of these by-products, for example, those with a high content of CaO or MgO may expand or powder over time, or may leach minute amounts of metal components, and many of them have not been effectively used.
このような問題に対し、特許文献１には、溶融状態の製鋼スラグにＳｉＯ２含有物質と還元材とを添加し、還元材の一部または全部として、特殊な条件に適合した廃プラスチックを使用して溶融改質する技術が開示されている。特許文献１には、具体的な手段として、溶滓鍋中に保持された溶融転炉スラグに、浸漬ランスからＳｉＯ２含有物質と酸素を吹き込むと共に、還元用物質を吹込むことが開示されている。 To address these problems, Patent Document 1 discloses a technology for melting and reforming molten steelmaking slag by adding a SiO2- containing material and a reducing agent to the molten steelmaking slag and using waste plastics that meet special conditions as part or all of the reducing agent. Patent Document 1 discloses, as a specific method, blowing a reducing material into molten converter slag held in a slag ladle together with blowing a SiO2 -containing material and oxygen from an immersion lance.
特許文献１に開示された技術は、溶融製鋼スラグに適用するものであるが、金属精錬工程において発生するスラグは、生成直後は溶融しているものの経時的に冷却されて固体状態になっているものがほとんどであり、特許文献１に開示される技術を有効に実施できる機会はあまりない。さらには、金属精錬工程において発生するダストは、固体状態で生成されるので、特許文献１に開示される技術では処理できない。 The technology disclosed in Patent Document 1 is applied to molten steelmaking slag, but most slag generated in metal refining processes is molten immediately after production, but cools over time and becomes solid, so there are few opportunities to effectively implement the technology disclosed in Patent Document 1. Furthermore, dust generated in metal refining processes is generated in a solid state, so it cannot be treated using the technology disclosed in Patent Document 1.
本発明は、このような従来技術の問題点を鑑みてなされたものであり、その目的は、常温のスラグやダスト等の副生成物を加熱溶融させ、金属分と酸化物成分とを有用な材料として分離するとともに、加熱溶融するための加熱炉を効率的に運用できる副生成物の処理方法を提供することである。 The present invention was made in consideration of the problems of the conventional technology, and its purpose is to provide a method for processing by-products that heats and melts slag, dust, and other by-products at room temperature, separates the metal and oxide components as useful materials, and allows efficient operation of the heating furnace used for heating and melting.
上記課題を解決するための手段は、以下の通りである。
（１）金属製造工程で発生する副生成物を加熱して前記副生成物を金属と酸化物とに分離する副生成物の処理方法であって、前記副生成物は、スラグ、ダスト、スラッジおよび使用後耐火物から選ばれる１種以上であり、前記副生成物は、電気炉を用いて１５００℃以上に加熱された後に別の容器に排出され、該容器内で金属アルミニウムおよび金属シリコンから選ばれる１種以上と混合されて金属と酸化物に分離され、前記酸化物の化学組成は、ＣａＯ：１７質量％以上５９質量％以下、ＳｉＯ２：１７質量％以上５３質量％以下、Ａｌ２Ｏ３：５質量％以上４５質量％以下、ＭｇＯ：２質量％以上２０質量％以下、塩基度（ＣａＯ／ＳｉＯ２）：０．７以上２．０以下である、副生成物の処理方法。
（２）前記副生成物は、金属および遊離炭素から選ばれる１種以上を合計で１質量％以上含有し、前記電気炉は抵抗加熱式電気炉である、（１）に記載の副生成物の処理方法。
（３）前記塩基度（ＣａＯ／ＳｉＯ２）は０．７以上１．６以下である、（１）または（２）に記載の副生成物の処理方法。
（４）前記副生成物が別の容器に排出される際に、金属アルミニウムおよび金属シリコンから選ばれる１種以上が、予め別の容器内に投入され、もしくは前記排出と同時に容器内へ投入されて、前記副生成物に混合される、（１）から（３）のいずれか１つに記載の副生成物の処理方法。
（５）前記副生成物が別の容器に排出された後に、金属アルミニウムおよび金属シリコンから選ばれる１種以上が前記副生成物に投入されて混合される、（１）から（３）のいずれか１つに記載の副生成物の処理方法。
（６）前記スラグおよび使用後耐火物は還元材を含有する、（１）から（５）のいずれか１つに記載の副生成物の処理方法。
（７）前記酸化物の化学組成を目標の範囲に調整するために、フライアッシュ、砂および砂利から選ばれる１種以上を前記副生成物に混合し、前記電気炉を用いて１５００℃以上に加熱する（１）から（６）のいずれか１つに記載の副生成物の処理方法。
The means for solving the above problems are as follows.
(1) A method for treating by-products generated in a metal production process, comprising heating the by-products and separating the by-products into metal and oxide, the by-products being one or more selected from slag, dust, sludge and used refractories, the by-products being heated to 1500°C or higher using an electric furnace and then discharged into another container, where they are mixed with one or more selected from metallic aluminum and metallic silicon and separated into metal and oxide, the chemical composition of the oxides being CaO: 17% by mass or more and 59% by mass or less, SiO2 : 17% by mass or more and 53% by mass or less, Al2O3 : 5% by mass or more and 45% by mass or less , MgO: 2% by mass or more and 20% by mass or less, and basicity (CaO/ SiO2 ): 0.7 to 2.0.
(2) The method for treating by-products according to (1), wherein the by-products contain at least one type selected from metals and free carbon in a total amount of at least 1 mass%, and the electric furnace is a resistance heating electric furnace.
(3) The method for treating by-products according to (1) or (2), wherein the basicity (CaO/SiO 2 ) is 0.7 or more and 1.6 or less.
(4) The method for treating a by-product according to any one of (1) to (3), wherein when the by-product is discharged into a separate container, one or more selected from metallic aluminum and metallic silicon are charged into the separate container in advance, or are charged into the container simultaneously with the discharge, and mixed with the by-product.
(5) The method for treating a by-product according to any one of (1) to (3), wherein after the by-product is discharged into another container, one or more selected from metallic aluminum and metallic silicon are added to and mixed with the by-product.
(6) The method for treating by-products according to any one of (1) to (5), wherein the slag and the used refractory contain a reducing material.
(7) The method for treating a by-product according to any one of (1) to (6), further comprising mixing the by-product with one or more selected from fly ash, sand and gravel in order to adjust the chemical composition of the oxide to a target range, and heating the mixture to 1,500° C. or higher using the electric furnace.
本発明に係る副生成物の処理方法の実施により、加熱炉を効率的に運用しつつ、常温のスラグやダスト等の副生成物を、路盤材やコンクリート等の骨材に利用できる有用な酸化物と、製鉄原料に利用できる有用な金属とに分離できる。 By implementing the by-product processing method of the present invention, it is possible to efficiently operate the heating furnace while separating by-products such as slag and dust at room temperature into useful oxides that can be used as aggregates for roadbed materials and concrete, and useful metals that can be used as raw materials for steelmaking.
本発明者らは、金属製錬または精錬工程（特に、鉄鋼精錬工程）において発生する副生成物であるスラグ、ダスト、スラッジおよび使用後耐火物には、金属または遊離炭素の何れかあるいは両方を含むものがあることに着目した。副生成物に金属または遊離炭素が含まれていれば、例えば、抵抗加熱式電気炉を用いて副生成物に通電することで発熱させ、常温の副生物であっても部分的に溶融させ、さらに通電することでこれらを全体的に溶融させることができる。あるいは、アーク炉であればアーク熱により副生成物を溶融させることができる。その後、溶融させた副生成物を別の容器に移してスラグやダスト等の副生成物を金属と酸化物に分離させることで、加熱炉を効率的に運用しつつ金属製造工程で発生する副生成物を金属と酸化物とに分離できることを見出して本発明に想到した。以下、発明の実施形態を通じて本発明を説明する。 The inventors have noticed that slag, dust, sludge, and used refractories, which are by-products generated in metal smelting or refining processes (particularly steel refining processes), contain either metal or free carbon, or both. If the by-products contain metal or free carbon, for example, a resistance heating electric furnace can be used to pass electricity through the by-products to generate heat, and even by-products at room temperature can be partially melted, and further electricity can be passed through to melt them as a whole. Alternatively, an arc furnace can melt the by-products using arc heat. The inventors have found that by-products generated in metal manufacturing processes can be separated into metal and oxide while efficiently operating the heating furnace by transferring the melted by-products to another container and separating the by-products such as slag and dust into metal and oxide, and have come up with the present invention. The present invention will be described below through an embodiment of the invention.
本実施形態に係る副生成物の処理方法では、電気炉を用いて、副生成物を１５００℃以上に加熱する。副生成物を１５００℃以上に加熱することで、副生成物を溶融させ、且つ、その後、副生成物を別の容器に移したとしても溶融状態を維持できる。一方、加熱温度が１５００℃未満であると、副生成物を別の容器に移した場合に溶融状態を維持できない場合があり、副生成物を酸化物と金属とに十分に分離できず酸化物に残留する金属が多くなる。 In the by-product processing method according to this embodiment, the by-product is heated to 1500°C or higher using an electric furnace. By heating the by-product to 1500°C or higher, the by-product is melted, and the molten state can be maintained even if the by-product is subsequently transferred to another container. On the other hand, if the heating temperature is less than 1500°C, the by-product may not be able to maintain the molten state when transferred to another container, and the by-product cannot be sufficiently separated into oxide and metal, resulting in a large amount of metal remaining in the oxide.
酸化物の温度が高いほど粘度が低減し、酸化物と金属との分離が容易となるので、副生成物の加熱温度の上限は特に定めなくてよいが、２０００℃程度まで上げても問題はない。副生成物の加熱には投入できるエネルギーが大きく、温度制御が容易である電気炉を用いることが好ましい。電気炉としては、抵抗加熱式電気炉、アーク炉、誘導加熱式電気炉等種々のものが使用できる。アーク炉や誘導加熱式電気炉を用いる場合は、副生成物に溶銑等の溶融金属や金属スクラップ等を加えて処理することもできる。 The higher the temperature of the oxide, the lower the viscosity and the easier it is to separate the oxide from the metal, so there is no need to set an upper limit for the heating temperature of the by-products, but there is no problem even if it is raised to about 2000°C. It is preferable to use an electric furnace for heating the by-products, which has a large amount of energy that can be input and is easy to control the temperature. As the electric furnace, various types such as a resistance heating electric furnace, an arc furnace, and an induction heating electric furnace can be used. When using an arc furnace or an induction heating electric furnace, molten metal such as hot metal or metal scrap can be added to the by-products for processing.
これら電気炉の中でも抵抗加熱式電気炉を用いることが好ましい。例えば、アーク炉では電極間でアーク放電を行い、そのアーク放電により生じる熱を副生物へ伝熱させて溶融させる必要がある。これに対して、副生成物であるスラグ、ダスト等に金属または遊離炭素が合計で１質量％以上含まれていれば、抵抗加熱式電気炉を用いることで、この金属や遊離炭素中を電気が流れて抵抗発熱し、この熱が直接副生成物に伝熱するので副生成物への伝熱が効率的に行われる。このため、アーク炉で加熱する場合に比べて、五分の一程度の時間で所定温度まで副生成物を昇温させることができる。実施形態における副生成物は、金属製造工程で発生するスラグ、ダスト、スラッジおよび使用後耐火物から選ばれる１種以上である。以後の説明では、電気炉として抵抗加熱式電気炉を用い、副生成物としてスラグおよびダストを用いたとして説明する。 Among these electric furnaces, it is preferable to use a resistance heating electric furnace. For example, in an arc furnace, an arc discharge is performed between electrodes, and the heat generated by the arc discharge must be transferred to the by-products to melt them. In contrast, if the by-products, such as slag and dust, contain a total of 1 mass% or more of metal or free carbon, a resistance heating electric furnace is used, and electricity flows through the metal or free carbon to generate resistance heat, which is then transferred directly to the by-products, so that heat transfer to the by-products is efficient. Therefore, the by-products can be heated to a predetermined temperature in about one-fifth the time required for heating in an arc furnace. The by-products in the embodiment are one or more selected from slag, dust, sludge, and used refractories generated in the metal manufacturing process. In the following explanation, a resistance heating electric furnace is used as the electric furnace, and slag and dust are used as the by-products.
副生成物であるスラグやダストを抵抗加熱式電気炉内に装入する。スラグおよびダストが堆積した炉内に電極を差し込み、電圧を印加する。このとき、スラグおよびダストに金属および遊離炭素が合計で１質量％以上存在することでスラグやダストに部分的に電流が流れ、これにより抵抗熱が発生してスラグやダストが昇温する。 The by-products, slag and dust, are loaded into a resistance-heated electric furnace. Electrodes are inserted into the furnace where the slag and dust have accumulated, and a voltage is applied. At this time, since the slag and dust contain a total of 1% by mass or more of metal and free carbon, current flows partially through the slag and dust, which generates resistance heat and raises the temperature of the slag and dust.
スラグやダストの主成分は金属酸化物なので、溶融状態では電気伝導性を有する。このため、昇温によりスラグやダスト自体が溶融するようになると、流れる電流の量も増加する。これにより発熱量も増加していき、炉内に装入したスラグやダストは１５００℃以上に加熱され、スラグやダストは全体的に溶融する。 The main components of slag and dust are metal oxides, so they are electrically conductive when molten. For this reason, when the temperature rises and the slag or dust itself begins to melt, the amount of current flowing also increases. This causes an increase in the amount of heat generated, and the slag and dust charged into the furnace are heated to over 1500°C, causing the slag and dust to melt entirely.
スラグおよびダストが抵抗加熱式電気炉で溶融された後、溶融状態のスラグおよびダストは抵抗加熱式電気炉から別の容器に排出される。スラグおよびダストは抵抗式加熱炉で１５００℃以上に加熱されているので、抵抗式加熱式電気炉から別の容器に排出したとしてもスラグおよびダストの溶融状態が維持される。また、スラグやダストに含まれる鉄や銅、ニッケル等の金属分も溶融して凝集するので、別の容器においてスラグおよびダストを金属と酸化物とに分離できる。別の容器とは、例えば、排滓鍋である。 After the slag and dust are melted in the resistance heating electric furnace, the molten slag and dust are discharged from the resistance heating electric furnace into a separate container. Because the slag and dust are heated to over 1500°C in the resistance heating furnace, the molten state of the slag and dust is maintained even when they are discharged from the resistance heating electric furnace into a separate container. In addition, the metals contained in the slag and dust, such as iron, copper, and nickel, also melt and coagulate, so the slag and dust can be separated into metals and oxides in the separate container. The separate container is, for example, a slag pan.
溶融状態のスラグおよびダストは抵抗加熱式電気炉から別の容器に排出する際に、金属アルミニウムおよび金属シリコンから選ばれる１種以上を溶融状態のスラグおよびダストと混合することで、別の容器の内部で溶融状態のスラグおよびダスト中の未還元の酸化鉄や酸化ニッケル、酸化マンガン、酸化クロムといった金属酸化物を還元して、金属の回収量を増やすことができる。 When the molten slag and dust are discharged from the resistance-heated electric furnace into a separate container, one or more selected from metallic aluminum and metallic silicon are mixed with the molten slag and dust, thereby reducing the unreduced metal oxides in the molten slag and dust inside the separate container, such as iron oxide, nickel oxide, manganese oxide, and chromium oxide, and increasing the amount of metal recovered.
金属アルミニウムおよび金属シリコンから選ばれる１種以上を予め別の容器内に投入しておき、そこへ溶融状態のスラグおよびダストを排出させてもよい。これにより、溶融状態のスラグおよびダストが当該容器内に排出されて流動する時に、金属アルミニウムや金属シリコンを巻き込ませ、これにより、溶融状態のスラグおよびダスト中に金属アルミニウムや金属シリコンを分散させることができる。 One or more selected from metallic aluminum and metallic silicon may be placed in a separate container in advance, and the molten slag and dust may be discharged therein. In this way, when the molten slag and dust are discharged into the container and flow, the metallic aluminum and metallic silicon are entrained, and thus the metallic aluminum and metallic silicon can be dispersed in the molten slag and dust.
また、溶融状態のスラグおよびダストを別の容器内へ排出する際に、金属アルミニウム、および金属シリコンから選ばれる１種以上を、当該別の容器内へ一緒に投入して、両者を混合、撹拌してもよい。また、溶融状態のスラグおよびダストを別の容器内へ投入した後に、別の容器内へ金属アルミニウム、および金属シリコンから選ばれる１種以上を投入して、混合、撹拌してもよい。この場合、混合、撹拌の手段として、インペラを用いて機械的に混合、撹拌できる。または、別の容器の底部に羽口を設けておき、窒素ガスやアルゴンガス等のガスを羽口から吹込み、上昇するガスにより混合、撹拌してもよい。 When the molten slag and dust are discharged into another vessel, one or more selected from metallic aluminum and metallic silicon may be added to the vessel together and mixed and stirred. After the molten slag and dust are added to the vessel, one or more selected from metallic aluminum and metallic silicon may be added to the vessel and mixed and stirred. In this case, the mixing and stirring can be performed mechanically using an impeller. Alternatively, a tuyere may be provided at the bottom of the vessel, and a gas such as nitrogen gas or argon gas may be blown in through the tuyere, and the rising gas may be used to mix and stir the mixture.
本実施形態に係る副生成物の処理方法では、酸化物の化学組成をＣａＯ：１７質量％以上５９質量％以下、ＳｉＯ２：１７質量％以上５３質量％以下、Ａｌ２Ｏ３：５質量％以上４５質量％以下、ＭｇＯ：２質量％以上２０質量％以下、塩基度（ＣａＯ／ＳｉＯ２）：０．７以上２．０以下にしている。酸化物の化学組成を上記範囲とすることで、溶融酸化物の粘性が溶融金属と分離するのに好ましい範囲となり、副生成物に含まれる金属と酸化物との分離が容易となる。さらに、酸化物の化学組成を上記範囲とすることで、酸化物の水和膨張も抑制され、路盤材やコンクリート等の骨材にも利用できる有用な材料となる。一方、酸化物の塩基度（ＣａＯ／ＳｉＯ２）が２．０より高くなると、溶融酸化物の粘度が高くなって金属と酸化物とが分離しづらくなり、分離後に酸化物に混入する金属が多くなる。また、酸化物の塩基度（ＣａＯ／ＳｉＯ２）が２．０より高くなったり、ＭｇＯが２０質量％より多くなると、酸化物からｆ－ＣａＯやｆ－ＭｇＯが析出しやすくなり、水和膨張が生じる。 In the by-product processing method according to the present embodiment, the chemical composition of the oxide is CaO: 17% by mass to 59% by mass, SiO 2 : 17% by mass to 53% by mass, Al 2 O 3 : 5% by mass to 45% by mass , MgO: 2% by mass to 20% by mass, and basicity (CaO/SiO 2 ): 0.7 to 2.0. By setting the chemical composition of the oxide in the above range, the viscosity of the molten oxide is in a range that is favorable for separation from the molten metal, and separation of the metal and oxide contained in the by-product is facilitated. Furthermore, by setting the chemical composition of the oxide in the above range, the hydration expansion of the oxide is also suppressed, making it a useful material that can also be used as an aggregate for roadbed materials and concrete. On the other hand, if the basicity (CaO/SiO 2 ) of the oxide is higher than 2.0, the viscosity of the molten oxide increases, making it difficult to separate the metal and the oxide, and more metal is mixed into the oxide after separation. Furthermore, if the basicity (CaO/SiO 2 ) of the oxide exceeds 2.0 or if the MgO content exceeds 20 mass %, f-CaO and f-MgO tend to precipitate from the oxide, causing hydration expansion.
酸化物の塩基度（ＣａＯ／ＳｉＯ２）は、０．７以上１．６以下であることが好ましい。酸化物の塩基度度（ＣａＯ／ＳｉＯ２）を、０．７以上１．６以下にすることで溶融酸化物の粘度が低くなり、金属と酸化物とがさらに分離し易くなる。さらに、酸化物の冷却過程における酸化物の体積変化や、酸化物からのｆ－ＣａＯおよびｆ－ＭｇＯの析出が抑制され、これにより、酸化物の粉化を抑制でき、水和膨張をさらに抑制できる。一方、酸化物の塩基度（ＣａＯ／ＳｉＯ２）が１．６より高くなると、酸化物の冷却過程での２ＣａＯ・ＳｉＯ２の結晶転移（α’型またはβ型からγ型への転移）によって体積が変化しはじめ、これにより、酸化物が粉化するので好ましくない。 The basicity of the oxide (CaO/SiO 2 ) is preferably 0.7 or more and 1.6 or less. By setting the basicity of the oxide (CaO/SiO 2 ) to 0.7 or more and 1.6 or less, the viscosity of the molten oxide is lowered, and the metal and the oxide are more easily separated. Furthermore, the volume change of the oxide during the cooling process of the oxide and the precipitation of f-CaO and f-MgO from the oxide are suppressed, thereby suppressing the powdering of the oxide and further suppressing the hydration expansion. On the other hand, if the basicity of the oxide (CaO/SiO 2 ) is higher than 1.6, the volume begins to change due to the crystal transition of 2CaO.SiO 2 (transition from α' type or β type to γ type) during the cooling process of the oxide, which is not preferable because it causes the oxide to be powdered.
さらに、酸化物の化学組成はＣａＯ、ＳｉＯ２、Ａｌ２Ｏ３、ＭｇＯの合計が８０質量％以上であることが好ましい。ＣａＯ、ＳｉＯ２、Ａｌ２Ｏ３、ＭｇＯの合計が８０質量％以上であることは、酸化物に含まれるＦｅＯ、Ｆｅ２Ｏ３およびＣｒ２Ｏ３が少ないことを意味する。上記化学組成を満足することで、副生成物に含まれる金属分の多くを金属として分離・回収できることがわかる。 Furthermore, the chemical composition of the oxide is preferably such that the total of CaO, SiO2 , Al2O3 , and MgO is 80 mass% or more. The total of CaO, SiO2 , Al2O3 , and MgO being 80 mass% or more means that the oxide contains small amounts of FeO, Fe2O3 , and Cr2O3 . It can be seen that by satisfying the above chemical composition, most of the metals contained in the by-products can be separated and recovered as metals.
酸化物の化学組成は、抵抗加熱式電気炉に装入するスラグ、ダスト、スラッジおよび使用後耐火物の化学組成を予め確認しておき、装入するスラグ、ダスト、スラッジおよび使用後耐火物の割合を調整することで制御できる。また、酸化物の化学組成を調整する原料として、フライアッシュ、砂および砂利から選ばれる１種以上を更に加えてもよく、これらを加えることで酸化物の化学組成、特に、酸化物の塩基度が適正な範囲になるように制御できる。 The chemical composition of the oxide can be controlled by checking in advance the chemical compositions of the slag, dust, sludge, and used refractories to be charged into the resistance-heated electric furnace, and adjusting the ratio of the slag, dust, sludge, and used refractories to be charged. In addition, one or more types selected from fly ash, sand, and gravel may be further added as raw materials to adjust the chemical composition of the oxide, and by adding these, the chemical composition of the oxide, and in particular the basicity of the oxide, can be controlled to be within an appropriate range.
ここで、ダストには、酸化物の塩基度をあげつつ回収する粒径を大きくして回収し易くする効果があるものがある。スラッジには、酸化物の塩基後を上げつつ還元を行う効果があるものがある。使用後耐火物には、酸化物の塩基度を下げつつ還元を行う効果があるものがある。フライアッシュ、砂、砂利は酸化物の塩基度を下げる効果があるものがある。これらの効果を考慮しながら、各原料の配合割合を調整しつつ酸化物の化学組成を上記範囲内に制御することで、ガラス化や膨張源を無くし、当該酸化物を路盤材やコンクリート等の骨材に利用できる有用な材料にできる。 Here, some dust has the effect of increasing the oxide basicity while increasing the particle size to be collected, making it easier to collect. Some sludge has the effect of reducing the oxide while increasing its basicity. Some used refractories have the effect of reducing the oxide while decreasing its basicity. Some fly ash, sand, and gravel have the effect of lowering the oxide basicity. By taking these effects into consideration and adjusting the blending ratio of each raw material while controlling the chemical composition of the oxide within the above range, it is possible to eliminate sources of vitrification and expansion, and turn the oxide into a useful material that can be used as an aggregate for roadbed materials, concrete, etc.
また、金属アルミニウムおよび金属シリコンから選ばれる１種以上をスラグおよびダストに混合して金属酸化物の還元操作を別の容器内で行うようにすることで、抵抗加熱式電気炉は副生成物の溶融に専念し、金属分の還元、回収は主として別の容器内で行うことができるので、抵抗加熱式電気炉の稼働率を向上させることができ、本実施形態に係る副生成物の処理方法における副生成物の処理量が増加する。一方、抵抗加熱式電気炉で金属酸化物を還元すると、抵抗加熱式電気炉の耐火物の損耗が著しくなり、耐火物の補修までの間隔が短くなる。これにより、抵抗加熱式電気炉の稼働率が低下するので、本実施形態に係る副生成物の処理方法における副生成物の処理量が減少する。 In addition, by mixing one or more selected from metallic aluminum and metallic silicon with the slag and dust and performing the reduction operation of the metal oxide in a separate container, the resistance heating electric furnace can be dedicated to melting the by-products, and the reduction and recovery of the metal components can be mainly performed in a separate container, so that the operating rate of the resistance heating electric furnace can be improved and the amount of by-products processed in the by-product processing method of this embodiment can be increased. On the other hand, when metal oxides are reduced in a resistance heating electric furnace, the wear of the refractory of the resistance heating electric furnace becomes significant, and the interval until the refractory is repaired becomes shorter. This reduces the operating rate of the resistance heating electric furnace, and the amount of by-products processed in the by-product processing method of this embodiment can be reduced.
また、抵抗加熱式電気炉への副生成物の装入は、低温で融液を生成するＦｅＯ、ＭｎＯ、Ａｌ２Ｏ３を含む原料を先に抵抗加熱式電気炉内に装入し、電圧を印加して溶融させた後に、順次他の原料を装入することが好ましい。これにより、高い効率で副生成物を全体的に溶融できる。さらに、最も低温で融液を生成する原料に加えて、原料全体の融点を低下させる原料を先に装入してもよい。 In addition, it is preferable to charge the by-products into the resistance heating electric furnace first with raw materials containing FeO, MnO , and Al2O3 that generate a melt at a low temperature, and then sequentially charge the other raw materials after applying a voltage to melt them. This allows the by-products to be melted as a whole with high efficiency. Furthermore, in addition to the raw material that generates a melt at the lowest temperature, a raw material that lowers the melting point of the entire raw materials may be charged first.
さらに、抵抗加熱式電気炉の炉壁耐火物保護のために、装入した副生成物の全てを溶解するのではなく、炉壁近傍の副生成物は溶解しないように操業してもよい。例えば、副生成物の全てが溶解しないように抵抗加熱式電気炉の電極を中心に寄せて操業してもよい。このように、炉壁近傍の副生成物は溶解しないように操業することで、セルフライニング層を形成する耐火物の溶損が少なくなり、この結果、耐火物の補修までの間隔が長くなる。なお、副生成物の全量が溶解しないように操業する場合には、溶融した副生成物を別の容器に排出する際に、溶解していない部分が混合しないようにする。 Furthermore, in order to protect the refractory of the furnace walls of a resistance-heated electric furnace, the furnace may be operated so that the by-products near the furnace walls do not melt, rather than melting all of the by-products charged. For example, the electrodes of the resistance-heated electric furnace may be moved to the center so that not all of the by-products melt. In this way, by operating the furnace so that the by-products near the furnace walls do not melt, the refractory that forms the self-lining layer is less likely to melt, and as a result, the interval until the refractory needs to be repaired is longer. When operating the furnace so that not all of the by-products melt, care must be taken to prevent the unmelted parts from mixing when discharging the molten by-products into a separate container.
以上説明したように、本実施形態に係る副生成物の処理方法では、副生成物中の酸化物が所定の化学成分になるようにスラグ、ダスト、スラッジおよび使用後耐火物から選ばれる１種以上を配合して抵抗加熱式電気炉に装入し、当該副生成物を１５００℃以上に加熱して、副生成物を溶融させる。その後、副生成物を別の容器に排出させ、当該別の容器で副生成物を酸化物と金属とに分離させる。これにより、抵抗加熱式電気炉の稼働率が向上し、本実施形態に係る副生成物の処理方法における副生成物の処理量を増やせる。さらに、副生成物を所定の化学成分の酸化物と金属とに分離できるので、常温の副生成物を路盤材やコンクリート等の骨材に利用できる有用な酸化物と、製鉄原料に利用できる有用な金属とに分離できる。 As described above, in the by-product processing method according to this embodiment, one or more selected from slag, dust, sludge, and used refractories are mixed so that the oxides in the by-products have a predetermined chemical composition, and the mixture is charged into a resistance heating electric furnace, where the by-products are heated to 1500°C or higher to melt the by-products. The by-products are then discharged into another container, where they are separated into oxides and metals. This improves the operating rate of the resistance heating electric furnace, and the amount of by-products processed in the by-product processing method according to this embodiment can be increased. Furthermore, since the by-products can be separated into oxides and metals of a predetermined chemical composition, the by-products at room temperature can be separated into useful oxides that can be used as aggregates for roadbed materials and concrete, and useful metals that can be used as raw materials for steelmaking.
次に、本発明に係る副生成物の処理方法の実施例を説明する。まず、１００ｋＶＡの抵抗加熱式電気炉に常温の副生成物を２０ｋｇ装入し、当該副生成物に電極を差し込み、通電を開始した。電極間の副生成物の溶融が確認された後に原料を追装していき、２００ｋｇの副生成物を装入し、１５００℃以上の所定温度にした後に別の容器に排出し、当該容器で副生成物に金属アルミニウムまたは金属シリコンを加え、インペラを用いて１時間撹拌して、副生成物を金属と酸化物とに分離した。 Next, an example of the by-product processing method according to the present invention will be described. First, 20 kg of room temperature by-products were charged into a 100 kVA resistance heating electric furnace, electrodes were inserted into the by-products, and electricity was started. After it was confirmed that the by-products between the electrodes had melted, raw materials were added until 200 kg of by-products were charged, and after heating to a specified temperature of 1500°C or higher, the by-products were discharged into another container, where metallic aluminum or metallic silicon was added to the by-products and stirred for one hour using an impeller to separate the by-products into metal and oxide.
副生成物である各原料の化学組成を表１に示す。表１中、製鋼スラグＢは、低温で融液を生成する原料である。フライアッシュや使用済耐火物は、原料全体の融点を低下させる原料である。また、Ｃｒ鉱石溶融還元炉スラグ、ＳＵＳダスト、冷延スラッジ、使用後耐火物およびフライアッシュは、還元材を含有する原料である。使用済耐火物に含まれる還元材は炭化ケイ素（ＳｉＣ）である。表１中の「＜０．１」は含有量が０．１質量％未満であることを示し、「＜１」は含有量が１質量％未満であることを示す。また、表１において、化学組成の和が１００に満たない材料があるが、この理由は、表１に示した原料が当該化学成分以外の他の成分を含むためである。 The chemical composition of each by-product raw material is shown in Table 1. In Table 1, steelmaking slag B is a raw material that produces a molten liquid at a low temperature. Fly ash and used refractories are raw materials that lower the melting point of the raw materials as a whole. In addition, Cr ore smelting reduction furnace slag, SUS dust, cold-rolled sludge, used refractories, and fly ash are raw materials that contain a reducing agent. The reducing agent contained in the used refractory is silicon carbide (SiC). In Table 1, "<0.1" indicates that the content is less than 0.1 mass%, and "<1" indicates that the content is less than 1 mass%. In Table 1, there are materials whose chemical compositions do not sum to 100. This is because the raw materials shown in Table 1 contain other components in addition to the chemical components in question.
発明例１～３６における各原料の配合割合を表２～５に示す。同様に、比較例１～１９における各原料の配合割合を表６、７に示す。表２～７における金属アルミニウムおよび金属シリコンはいずれも還元材である。 The blending ratios of each raw material in Examples 1 to 36 are shown in Tables 2 to 5. Similarly, the blending ratios of each raw material in Comparative Examples 1 to 19 are shown in Tables 6 and 7. Metallic aluminum and metallic silicon in Tables 2 to 7 are both reducing materials.
発明例１～３８における分離後の酸化物および金属の化学組成と酸化物と金属との分離状態を表８、表９に示す。同様に、比較例１～１９における分離後の酸化物および金属の化学組成と、酸化物と金属との分離状態を表１０に示す。なお、本実施例では酸化物への金属の混入量が１０質量％以下である場合に分離が良好とし、表８～１０の「分離」列に「〇」と記載した。一方、酸化物への金属の混入量が１０質量％より多い場合に分離が良好ではないとし、表８～１０の「分離」列に「×」と記載した。また、表８～１０の「＜１」は含有量が１質量％未満であることを意味する。 Tables 8 and 9 show the chemical composition of the oxide and metal after separation and the state of separation between the oxide and metal in Examples 1 to 38. Similarly, Table 10 shows the chemical composition of the oxide and metal after separation and the state of separation between the oxide and metal in Comparative Examples 1 to 19. In this example, separation was considered to be good when the amount of metal mixed into the oxide was 10% by mass or less, and is marked with "O" in the "Separation" column in Tables 8 to 10. On the other hand, separation was considered to be poor when the amount of metal mixed into the oxide was more than 10% by mass, and is marked with "X" in the "Separation" column in Tables 8 to 10. In addition, "<1" in Tables 8 to 10 means that the content is less than 1% by mass.
発明例１～１１、３７、３８は、製鋼スラグＡ、Ｂ、Ｃ、Ｄにダスト、スラッジ、使用後耐火物（耐火物屑Ａまたは耐火物屑Ｂ）、塩基度調整材（フライアッシュ）および還元材（金属アルミニウムまたは金属シリコン）を加えた発明例である。熱処理温度は１８００℃である。発明例１～１１では、別の容器に排出させた後でも副生成物の温度が１４００℃となり、金属の混入量１０質量％以下で所定の化学成分の酸化物が分離回収でき、路盤材やコンクリート等の骨材として使用できる緻密な酸化物が得られた。また、発明例１～１１では還元材（金属アルミニウムまたは金属シリコン）を加えているので、酸化物中のＦｅＯ＋Ｆｅ２Ｏ３濃度は２質量％以下、Ｃｒ２Ｏ３濃度は１質量％未満となり、酸化物中の金属を十分に回収することができた。なお、本実施例では塩基度調整材としてフライアッシュを用いたが、フライアッシュに代えて、砂、砂利を用いても同様の効果が得られる。 Examples 1 to 11, 37, and 38 are examples of the invention in which dust, sludge, used refractories (refractory scrap A or refractory scrap B), basicity adjuster (fly ash), and reducing agent (metallic aluminum or metallic silicon) are added to steelmaking slag A, B, C, and D. The heat treatment temperature is 1800°C. In Examples 1 to 11, the temperature of the by-products is 1400°C even after being discharged into a separate container, and oxides of a specified chemical composition can be separated and recovered with a metal contamination of 10% by mass or less, and dense oxides that can be used as aggregates for roadbeds and concrete are obtained. In Examples 1 to 11, a reducing agent (metallic aluminum or metallic silicon) is added, so that the FeO+Fe 2 O 3 concentration in the oxide is 2% by mass or less, and the Cr 2 O 3 concentration is less than 1% by mass, and the metals in the oxide can be sufficiently recovered. In this embodiment, fly ash is used as the basicity adjuster, but the same effect can be obtained by using sand or gravel instead of fly ash.
発明例１２～２２は、Ｃｒ鉱石溶融還元炉スラグにダスト、スラッジ、使用後耐火物（耐火物屑Ａまたは耐火物屑Ｂ）、塩基度調整材（フライアッシュ）および還元材（金属アルミニウムまたは金属シリコン）を加えた発明例である。熱処理温度は１８００℃である。発明例１２～２２においても、別の容器に排出させた後でも副生成物の温度が１４００℃となり、金属の混入量１０質量％以下で所定の化学成分の酸化物が分離回収でき、路盤材やコンクリート等の骨材として使用できる緻密な酸化物が得られた。また、発明例１２～２２においても還元材（金属アルミニウムまたは金属シリコン）を加えているので、酸化物中のＦｅＯ＋Ｆｅ２Ｏ３濃度は１質量％以下、Ｃｒ２Ｏ３濃度は１質量％未満となり、酸化物中の金属を十分に回収することができた。 Inventive Examples 12 to 22, dust, sludge, used refractories (refractory scrap A or refractory scrap B), basicity adjuster (fly ash) and reducing agent (metallic aluminum or metallic silicon) were added to the Cr ore smelting reduction furnace slag. The heat treatment temperature was 1800°C. In Inventive Examples 12 to 22, the temperature of the by-products was 1400°C even after being discharged into a separate container, and oxides of a specified chemical composition were separated and recovered with a metal contamination of 10% by mass or less, and dense oxides that can be used as aggregates for roadbeds and concrete were obtained. In Inventive Examples 12 to 22, a reducing agent (metallic aluminum or metallic silicon) was also added, so that the FeO+Fe 2 O 3 concentration in the oxide was 1% by mass or less, and the Cr 2 O 3 concentration was less than 1% by mass, and the metals in the oxide were sufficiently recovered.
発明例２３～３３は、銅スラグにダスト、スラッジ、使用後耐火物（耐火物屑Ａまたは耐火物屑Ｂ）、塩基度調整材（フライアッシュ）、還元材（金属アルミニウムまたは金属シリコン）を加えた発明例である。熱処理温度は１８００℃である。発明例２３～３３においても、別の容器に排出させた後でも副生成物の温度が１４００℃となり、金属の混入量１０質量％以下で所定の化学成分の酸化物が分離回収でき、路盤材やコンクリート等の骨材として使用できる緻密な酸化物が得られた。また、発明例２３～３３においても還元材（金属アルミニウムまたは金属シリコン）を加えているので、酸化物中のＦｅＯ＋Ｆｅ２Ｏ３濃度は２質量％以下、Ｃｒ２Ｏ３濃度は１質量％未満となり、酸化物中の金属を十分に回収することができた。 Inventive Examples 23 to 33, dust, sludge, used refractories (refractory scrap A or refractory scrap B), basicity adjuster (fly ash), and reducing agent (metallic aluminum or metallic silicon) were added to copper slag. The heat treatment temperature was 1800°C. In Inventive Examples 23 to 33, the temperature of the by-product was 1400°C even after it was discharged into a separate container, and oxides of a specified chemical composition were separated and recovered with a metal contamination of 10% by mass or less, and dense oxides that can be used as aggregates for roadbeds and concrete were obtained. In Inventive Examples 23 to 33, a reducing agent (metallic aluminum or metallic silicon) was also added, so that the FeO+Fe 2 O 3 concentration in the oxide was 2% by mass or less, and the Cr 2 O 3 concentration was less than 1% by mass, and the metals in the oxide were sufficiently recovered.
発明例３４～３６は、発明例２、１６、２８と同じの原料配合であって、熱処理温度を１６００℃とした発明例である。発明例３４～３６においても金属の混入量１０質量％以下で所定の化学成分の酸化物が分離回収でき、路盤材やコンクリート等の骨材として使用できる緻密な酸化物が得られた。 Invention examples 34 to 36 are invention examples that use the same raw material composition as invention examples 2, 16, and 28, but the heat treatment temperature was 1600°C. In invention examples 34 to 36, oxides of the specified chemical components could be separated and recovered with a metal contamination level of 10 mass% or less, and dense oxides that can be used as aggregates for roadbed materials, concrete, etc. were obtained.
比較例１～５は、製鋼スラグＡ、Ｂにスラッジ、使用済耐火物（耐火物屑Ａまたは耐火物屑Ｂ）および塩基度調整材（フライアッシュ）を加えた比較例である。熱処理温度は１８００℃である。比較例１は塩基度が２．１と高く、溶融状態の酸化物が高粘度となり、金属と酸化物とが分離しきらず、酸化物中に金属が多く混入した。また、比較例５は塩基度が６．１と高いために原料を完全に溶融させることができず、金属と酸化物とを分離させることができなかった。比較例２～４は塩基度が低く溶融状態の酸化物の粘度が低いたために、１０℃／ｍｉｎの冷却速度であっても酸化物がガラス化し、路盤材やコンクリート等の骨材として使用できる緻密な酸化物が得られなかった。 Comparative Examples 1 to 5 are comparative examples in which sludge, used refractories (scrap refractories A or scrap refractories B), and basicity adjuster (fly ash) were added to steelmaking slag A and B. The heat treatment temperature was 1800°C. Comparative Example 1 had a high basicity of 2.1, which resulted in high viscosity of the molten oxide, which prevented the metal and oxide from being completely separated, resulting in a large amount of metal being mixed into the oxide. Comparative Example 5 had a high basicity of 6.1, which prevented the raw materials from being completely melted, and the metal and oxide from being separated. Comparative Examples 2 to 4 had low basicity and low viscosity of the molten oxide, so the oxide was vitrified even at a cooling rate of 10°C/min, and dense oxides that could be used as aggregates for roadbeds and concrete could not be obtained.
比較例６～１１は、Ｃｒ鉱石溶融還元炉スラグにダスト、スラッジ、使用後耐火物（耐火物屑Ａまたは耐火物屑Ｂ）および塩基度調整材（フライアッシュ）を加えた比較例である。熱処理温度は１８００℃である。比較例６は基度が２．１と高く、溶融状態の酸化物が高粘度となり、金属と酸化物とが分離しきらず、酸化物中に金属が多く混入した。比較例９はＭｇＯ含有量が２２質量％と高いために酸化物が高粘度となり、金属と酸化物とが分離しきらず、酸化物中に金属が多く混入した。比較例１１は塩基度が６．２と高いために原料を完全に溶融させることができず、金属と酸化物とを分離させることができなかった。比較例７、８、１０は塩基度が０．１～０．６と低く、溶融状態の酸化物の粘度が低いために、１０℃／ｍｉｎの冷却速度であってもガラス化し、路盤材やコンクリート等の骨材として使用できる緻密な酸化物が得られなかった。 Comparative Examples 6 to 11 are comparative examples in which dust, sludge, used refractories (refractory scrap A or refractory scrap B) and basicity adjuster (fly ash) were added to the Cr ore melting reduction furnace slag. The heat treatment temperature was 1800°C. Comparative Example 6 had a high basicity of 2.1, which resulted in high viscosity of the molten oxide, which prevented the metal and oxide from being completely separated, and a large amount of metal was mixed into the oxide. Comparative Example 9 had a high MgO content of 22 mass%, which resulted in high viscosity of the oxide, which prevented the metal and oxide from being completely separated, and a large amount of metal was mixed into the oxide. Comparative Example 11 had a high basicity of 6.2, which prevented the raw materials from being completely melted, and the metal and oxide from being separated. Comparative Examples 7, 8, and 10 had low basicities of 0.1 to 0.6, which resulted in low viscosity of the molten oxide, which prevented the oxide from being vitrified even at a cooling rate of 10°C/min, and therefore did not produce dense oxides that could be used as aggregates for roadbeds and concrete.
比較例１２～１６は銅スラグにダスト、スラッジ、使用後耐火物（耐火物屑Ａ、耐火物屑Ｂ）および塩基度調整材（フライアッシュ）を加えた比較例である。熱処理温度は１５５０℃である。比較例１２は基度が２．１と高く、溶融状態の酸化物が高粘度となり、金属と酸化物とが分離しきらず、酸化物中に金属が多く混入した。比較例１６は塩基度が６．２と高いために原料を完全に溶融させることができず、金属と酸化物とを分離させることができなかった。比較例１３～１５は塩基度が０．１～０．６と低く、溶融状態の酸化物の粘度が低いために、１０℃／ｍｉｎの冷却速度であってもガラス化し、路盤材やコンクリート等の骨材として使用できる緻密な酸化物が得られなかった。 Comparative Examples 12 to 16 are comparative examples in which dust, sludge, used refractories (refractory scrap A, refractory scrap B), and basicity adjuster (fly ash) were added to copper slag. The heat treatment temperature was 1550°C. Comparative Example 12 had a high basicity of 2.1, which resulted in high viscosity of the molten oxide, which prevented the metal and oxide from being completely separated, resulting in a large amount of metal being mixed into the oxide. Comparative Example 16 had a high basicity of 6.2, which prevented the raw materials from being completely melted, and the metal and oxide from being separated. Comparative Examples 13 to 15 had a low basicity of 0.1 to 0.6, which resulted in low viscosity of the molten oxide, which resulted in vitrification even at a cooling rate of 10°C/min, and therefore did not produce a dense oxide that could be used as an aggregate for roadbeds, concrete, etc.
比較例１７は発明例１と同じ原料配合であって、熱処理温度を１４５０℃にした比較例である。比較例１８は発明例１３と同じ配合であって、熱処理温度を１３００℃にした比較例である。比較例１９は発明例２５と同じ配合であって、熱処理温度を１０００℃にした比較例である。これらの比較例はいずれも熱処理温度が１５００℃より低いために、別の容器に排出させた後の温度が１３００℃未満となり、原料を完全に溶融させることができず、金属と酸化物とを分離させることができなかった。 Comparative Example 17 is a comparative example in which the raw material composition is the same as that of Invention Example 1, but the heat treatment temperature is 1450°C. Comparative Example 18 is a comparative example in which the raw material composition is the same as that of Invention Example 13, but the heat treatment temperature is 1300°C. Comparative Example 19 is a comparative example in which the raw material composition is the same as that of Invention Example 25, but the heat treatment temperature is 1000°C. In all of these comparative examples, the heat treatment temperature is lower than 1500°C, so the temperature after being discharged into a separate container is less than 1300°C, and the raw materials cannot be completely melted, and the metal and oxide cannot be separated.
Claims (6)
前記副生成物は、スラグ、ダスト、スラッジおよび使用後耐火物から選ばれる１種以上であり、
前記副生成物は、電気炉を用いて１５００℃以上に加熱された後に別の容器に排出され、該容器内で金属アルミニウムおよび金属シリコンから選ばれる１種以上と混合されて金属と酸化物に分離され、
前記酸化物の化学組成は、ＣａＯ：１７質量％以上５９質量％以下、ＳｉＯ２：１７質量％以上５３質量％以下、Ａｌ２Ｏ３：５質量％以上４５質量％以下、ＭｇＯ：２質量％以上２０質量％以下、塩基度（ＣａＯ／ＳｉＯ２）：０．７以上２．０以下であり、
前記副生成物は、金属および遊離炭素から選ばれる１種以上を合計で１質量％以上含有し、前記電気炉は抵抗加熱式電気炉である、副生成物の処理方法。 A method for treating by-products generated in a metal manufacturing process, comprising heating the by-products to separate the by-products into metal and oxide, the method comprising the steps of:
The by-product is at least one selected from slag, dust, sludge, and used refractories,
The by-product is heated to 1500° C. or higher using an electric furnace, discharged into another container, and mixed with one or more selected from metallic aluminum and metallic silicon in the container to separate into metal and oxide;
The chemical composition of the oxides is as follows: CaO: 17% by mass or more and 59% by mass or less; SiO2: 17% by mass or more and 53% by mass or less; Al2O3 : 5 % by mass or more and 45% by mass or less; MgO: 2% by mass or more and 20% by mass or less; and basicity (CaO/ SiO2 ): 0.7 or more and 2.0 or less .
The method for treating a by-product , wherein the by-product contains at least one type selected from metals and free carbon in a total amount of at least 1 mass %, and the electric furnace is a resistance heating electric furnace .
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| JP2014521830A (en) | 2011-11-29 | 2014-08-28 | ヒュンダイ スチール カンパニー | Equipment for recovering valuable metals using slag and producing multifunctional aggregates |
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| JPS61194125A (en) * | 1985-02-23 | 1986-08-28 | Nippon Jiryoku Senko Kk | Simultaneous treatment of sludge and steel making slag |
| JPH1036148A (en) * | 1996-07-22 | 1998-02-10 | Sumitomo Metal Ind Ltd | Treatment of molten iron dephosphorized slag and slag |
| JP5444883B2 (en) * | 2009-06-26 | 2014-03-19 | 新日鐵住金株式会社 | Modified slag |
| JP5531536B2 (en) * | 2009-09-30 | 2014-06-25 | Ｊｆｅスチール株式会社 | Method for recovering iron and phosphorus from steelmaking slag |
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| JP2005306654A (en) | 2004-04-21 | 2005-11-04 | Nippon Steel Corp | Reforming method for steelmaking slag and reformed steelmaking slag |
| JP2014521830A (en) | 2011-11-29 | 2014-08-28 | ヒュンダイ スチール カンパニー | Equipment for recovering valuable metals using slag and producing multifunctional aggregates |
| JP2015504978A (en) | 2012-01-31 | 2015-02-16 | ヒュンダイ スチール カンパニー | Slag reduction method |
| WO2014003123A1 (en) | 2012-06-27 | 2014-01-03 | 新日鐵住金株式会社 | Steel slag reduction method |
| JP2016145125A (en) | 2015-02-06 | 2016-08-12 | 新日鐵住金株式会社 | Slag product raw material and manufacturing method therefor |
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