JP6460169B2 - Manufacturing method of steelmaking slag roadbed material - Google Patents
Manufacturing method of steelmaking slag roadbed material Download PDFInfo
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- JP6460169B2 JP6460169B2 JP2017142071A JP2017142071A JP6460169B2 JP 6460169 B2 JP6460169 B2 JP 6460169B2 JP 2017142071 A JP2017142071 A JP 2017142071A JP 2017142071 A JP2017142071 A JP 2017142071A JP 6460169 B2 JP6460169 B2 JP 6460169B2
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- 239000002893 slag Substances 0.000 title claims description 245
- 238000009628 steelmaking Methods 0.000 title claims description 134
- 239000000463 material Substances 0.000 title claims description 39
- 238000004519 manufacturing process Methods 0.000 title claims description 24
- 239000002245 particle Substances 0.000 claims description 151
- 230000032683 aging Effects 0.000 claims description 68
- 238000009826 distribution Methods 0.000 claims description 51
- 239000010419 fine particle Substances 0.000 claims description 43
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- 238000002156 mixing Methods 0.000 claims description 12
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- 238000007670 refining Methods 0.000 claims description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 35
- 238000007654 immersion Methods 0.000 description 23
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- 239000007787 solid Substances 0.000 description 13
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- 239000011362 coarse particle Substances 0.000 description 10
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 9
- 229910000831 Steel Inorganic materials 0.000 description 7
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- -1 MgO hydrates Chemical class 0.000 description 1
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- 238000003723 Smelting Methods 0.000 description 1
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- 239000002184 metal Substances 0.000 description 1
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Description
この発明は、製鋼スラグを加圧蒸気エージングして製造される製鋼スラグ路盤材の製造方法に関する。 The present invention relates to a method for producing a steelmaking slag roadbed material produced by pressurized steam aging of steelmaking slag.
製鋼スラグは、精錬で添加される石灰源やマグネシア源の一部が未溶融或いは他の成分と化合物を形成しないで遊離したまま残留している。このような遊離ＣａＯや遊離ＭｇＯが水分と水和反応すると、体積が２倍以上に膨張して周囲の構造物を破壊するため、製鋼スラグを石材や道路路盤材として利用するには、使用前の段階で水和反応を促進して沈静化しておく必要がある。 In the steelmaking slag, some of the lime source and magnesia source added by refining remain unmelted or free without forming a compound with other components. When such free CaO or free MgO hydrates with water, the volume expands more than twice and destroys surrounding structures. Therefore, before using steelmaking slag as a stone or roadbed material, It is necessary to promote hydration and calm down at this stage.
製鋼スラグ中の遊離ＣａＯや遊離ＭｇＯを水分と速やかに反応させるのに、昇温と水分供給を同時に行なう蒸気での反応促進（蒸気エージング）が一般的に実施されている。そのなかでも、高温高圧の蒸気を用いる加圧蒸気エージングは高速での処理が可能である。従来、この加圧蒸気エージングを実施するための装置やエージングパターンについての提案がいくつかなされている。 In order to rapidly react free CaO and free MgO in steelmaking slag with moisture, reaction promotion (steam aging) with steam that simultaneously raises temperature and supplies moisture is generally performed. Among them, pressurized steam aging using high-temperature and high-pressure steam can be processed at high speed. Conventionally, several proposals have been made on apparatuses and aging patterns for performing this pressurized steam aging.
特許文献１には、加圧蒸気エージング時の温度−圧力の推移パターンが示されており、加圧保持時の途中で蒸気圧を短時間下げ、再度高圧に昇圧して処理する方法が示されている。
また、特許文献２には、細粒で蒸気の進入が容易でないスラグでも加圧蒸気エージングを短時間で行うために、スラグ収納容器の内部に蒸気配管を通して、スラグ充填部の内部から蒸気を吹き込む方法が示されている。
Further, in
製鋼スラグを蒸気エージングするとスラグ粒子の一部は膨張反応で崩壊するため、粒度分布は細かい側に変化する。膨張を抑制しようとして、加圧蒸気エージングの時間を長くしたり、温度や圧力を高めたりすると、細粒化は進むが膨張性の安定化は鈍る。そうして、路盤材製品の膨張基準を満たすような安定した路盤材を製造するエージング処理の生産性が落ちる。
特許文献１の方法は、加圧蒸気エージング中の圧力変化により粒子の崩壊を進めて安定化を図るものであるが、粒子の新しい膨張源を露出させ続けるため、さらに膨張反応が進行する状態が生じ、安定化するのに非効率に細粒化が進みすぎる問題がある。また、特許文献２の方法は、細かい粒子にも蒸気は進入して昇温されるが、元が細かい粒子であると、より細粒化して膨張率の安定化は遅くなる。
When steam aging steelmaking slag, some of the slag particles collapse due to expansion reaction, so the particle size distribution changes to the fine side. If the time of pressurized steam aging is lengthened or the temperature or pressure is increased in an attempt to suppress the expansion, finer particles will progress, but the expansion stability will slow down. Thus, the productivity of the aging process for producing a stable roadbed material that satisfies the expansion standard of the roadbed material product is lowered.
The method of
したがって本発明の目的は、製鋼スラグを加圧蒸気エージングして製鋼スラグ路盤材を製造する方法において、膨張性が極めて低い製鋼スラグ路盤材を高い生産性で製造することができる製造方法を提供することにある。 Accordingly, an object of the present invention is to provide a production method capable of producing a steelmaking slag roadbed material having extremely low expansibility with high productivity in a method of producing a steelmaking slag roadbed material by pressurized steam aging of the steelmaking slag. There is.
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］粒径４０ｍｍ以下の割合が８０mass％以上となる粒度に破砕された製鋼スラグ（ａ）について、下記（ｉ）又は（ii）の条件で細粒・微粉分を増減することにより、製鋼スラグ（ａ）の粒度分布をAndreazenの曲線式で近似した場合に、Fuller指数が０．４〜０．６となるように製鋼スラグ（ａ）の粒度分布を調整した後、加圧蒸気エージングを施すことを特徴とする製鋼スラグ路盤材の製造方法。
（ｉ）製鋼スラグ（ａ）の一部について篩目が１０ｍｍ以下の篩（ｘ）で分級することで細粒・微粉分を減じた後、製鋼スラグ（ａ）の残部と混合する。
（ii）以前に、粒径４０ｍｍ以下の割合が８０mass％以上となる粒度に破砕された製鋼スラグを篩目が１０ｍｍ以下の篩（ｘ）で分級することで得られている細粒・微粉分を、製鋼スラグ（ａ）に加えて混合する。
The gist of the present invention for solving the above problems is as follows.
[1] Steelmaking slag (a) crushed to a particle size with a particle size of 40 mm or less being 80 mass% or more, by increasing or decreasing the fine particles / fine powder content under the following conditions (i) or (ii) When the particle size distribution of the slag (a) is approximated by Andreazen's curve formula, after adjusting the particle size distribution of the steelmaking slag (a) so that the Fuller index is 0.4 to 0.6, pressurized steam aging is performed. The manufacturing method of the steel-making slag roadbed material characterized by performing.
(I) A part of the steelmaking slag (a) is classified with a sieve (x) having a sieve mesh of 10 mm or less to reduce fine particles and fine powder, and then mixed with the remainder of the steelmaking slag (a).
(Ii) Fine particles and fine powder obtained by classifying steelmaking slag previously crushed to a particle size with a particle size of 40 mm or less being 80 mass% or more with a sieve (x) having a sieve mesh of 10 mm or less Is added to the steelmaking slag (a) and mixed.
［2］上記［1］の製造方法において、製鋼スラグ（ａ）が同日に同じ精錬設備で発生した脱炭スラグであり、該製鋼スラグ（ａ）の一部について篩目が１０ｍｍ以下の篩（ｘ）で分級することで細粒・微粉分を減じた後、製鋼スラグ（ａ）の残部と混合することにより、製鋼スラグ（ａ）の細粒・微粉分を減少させて粒度分布を調整することを特徴とする製鋼スラグ路盤材の製造方法。
［3］上記［1］の製造方法において、製鋼スラグ（ａ）が２種以上の製鋼スラグからなり、そのなかの１種の製鋼スラグ（ａ1）の全部又は一部について篩目が１０ｍｍ以下の篩（ｘ）で分級することで細粒・微粉分を減じた後、残りの１種以上の製鋼スラグ（ａ2）及び製鋼スラグ（ａ1）の残部（但し、製鋼スラグ（ａ1）の全部を上記分級した場合を除く。）と混合することにより、製鋼スラグ（ａ）の細粒・微粉分を減少させて粒度分布を調整することを特徴とする製鋼スラグ路盤材の製造方法。
[2] In the production method of [1] above, the steelmaking slag (a) is decarburized slag generated in the same refining equipment on the same day, and a sieve having a mesh size of 10 mm or less for a part of the steelmaking slag (a) ( After reducing the fine particles and fine powder by classifying in x), mixing with the remainder of the steelmaking slag (a) reduces the fine particles and fine powder of the steelmaking slag (a) and adjusts the particle size distribution. A method for producing a steelmaking slag roadbed material.
[3] In the manufacturing method of [1], the steelmaking slag (a) is composed of two or more types of steelmaking slag, and the mesh size of all or part of one type of steelmaking slag (a1) is 10 mm or less. After reducing the fines and fines by classifying with a sieve (x), the remaining one or more types of steelmaking slag (a2) and the remainder of the steelmaking slag (a1) (however, all of the steelmaking slag (a1) A method for producing a steelmaking slag roadbed material characterized by adjusting the particle size distribution by reducing the fine and fine particles of the steelmaking slag (a) by mixing with the above.
［4］上記［3］の製造方法において、製鋼スラグ（ａ1）が同日に同じ精錬設備で発生した脱炭スラグであり、製鋼スラグ（ａ2）が脱炭スラグ以外の製鋼スラグであることを特徴とする製鋼スラグ路盤材の製造方法。
［5］上記［1］〜［4］のいずれかの製造方法において、篩（ｘ）の篩目が５ｍｍ（但し、呼び径）であることを特徴とする製鋼スラグ路盤材の製造方法。
［6］上記［1］〜［5］のいずれかの製造方法において、加圧蒸気エージングでは、蒸気圧力０．２０〜１．９６ＭＰａで１〜５時間保持することを特徴とする製鋼スラグ路盤材の製造方法。
［7］上記［1］〜［6］のいずれかの製造方法において、加圧蒸気エージングした後の製鋼スラグの粒度が、ＪＩＳ Ａ５０１５（２０１３）に粒度範囲が定められているＣＳ−４０、ＣＳ−３０、ＣＳ−２０、ＭＳ−２５、ＨＭＳ−２５のいずれかの粒度範囲を満足することを特徴とする製鋼スラグ路盤材の製造方法。
[4] In the production method of [3] above, the steelmaking slag (a1) is decarburized slag generated in the same refining equipment on the same day, and the steelmaking slag (a2) is steelmaking slag other than decarburized slag. A method for producing steelmaking slag roadbed material.
[5] A method for producing a steel-making slag roadbed material, wherein the sieve (x) has a mesh size of 5 mm (however, nominal diameter) in the production method of any one of [1] to [4] above.
[6] In the manufacturing method according to any one of the above [1] to [5], in the pressurized steam aging, the steelmaking slag roadbed material is maintained at a steam pressure of 0.20 to 1.96 MPa for 1 to 5 hours. Manufacturing method.
[7] In the production method according to any one of [1] to [6] above, the particle size range of steelmaking slag after pressurized steam aging is CS-40, CS whose particle size range is defined in JIS A5015 (2013). A method for producing a steelmaking slag roadbed material satisfying any particle size range of -30, CS-20, MS-25, and HMS-25.
本発明によれば、適用したエージング条件で到達し得る最低レベルにまで膨張性を低減した製鋼スラグ路盤材を高い生産性で製造することできる。このため膨張性の製鋼スラグを従来と同じエージング条件や蒸気原単位で加圧蒸気エージングした場合でも、より多くの膨張率合格品（路盤材製品）を得ることができる。また、本発明法で製造された製鋼スラグ路盤材は、膨張性が極めて低いだけでなく、密度が高いため締め固め性にも優れている。 ADVANTAGE OF THE INVENTION According to this invention, the steel-making slag roadbed material which reduced the expansibility to the lowest level which can be reached | attained on the applied aging conditions can be manufactured with high productivity. For this reason, even when expandable steelmaking slag is subjected to pressurized steam aging under the same aging conditions and steam intensity as in the past, more expansion rate acceptable products (roadbed material products) can be obtained. Moreover, the steel-making slag roadbed material manufactured by the method of the present invention has not only extremely low expansibility but also excellent compactability because of its high density.
本発明者は以下のような実験を行った。
路盤材の膨張性評価に用いられる突き固め試験では、条件により突き固め回数が決められている。ＪＩＳ Ａ１２１０（２００９）に定められたＥ−ｂの方法では、内径１５０ｍｍの円筒容器（ＣＢＲ試験型枠）に１層につき４．５ｋｇのランマを９２回落下させて突き、これを３層で突いて高さ１２５ｍｍに突き固める。突き固めた供試体の質量が分かれば、事前に調整した含水比を基にして、乾燥時の供試体質量および密度が求められる。
The inventor conducted the following experiment.
In the tamping test used for the expansibility evaluation of the roadbed material, the number of tamping is determined depending on the conditions. In the E-b method defined in JIS A1210 (2009), a 4.5 kg rammer is dropped 92 times into a cylindrical container (CBR test form) with an inner diameter of 150 mm, and this is thrust into three layers. To a height of 125mm. If the mass of the solidified specimen is known, the specimen mass and density at the time of drying can be determined based on the moisture content adjusted in advance.
標準９２回／層×３層の突き固めを、４６回／層×３層、９２回／層×３層、１８４回／層×３層と変化させて製鋼スラグの突き固めを行い、突き固めた各供試体の乾燥密度を測定した。その結果を図１に示すが、突き固め回数を増やすと乾燥密度は増大している。一方、突き固めた供試体を８０℃に保持した水槽に浸漬して膨張の推移を計測した。図２に、この水浸試験での各供試体の膨張率の推移を示すが、膨張率は密度の小さい順に大きくなっている。すなわち、膨張率は４６回／層＞９２回／層＞１８４回／層となっている。上記３層の突き固めにおいて、１層だけ突き固めた時点の試料を採取し、粒度分布測定した結果を図３に示すが、突き固め回数が１８４回では粗粒が若干崩壊した様子が分かる。 The standard 92 times / layer x 3 layers tamping is changed to 46 times / layers x 3 layers, 92 times / layers x 3 layers, 184 times / layers x 3 layers, and the steelmaking slag is tamped and tamped. The dry density of each specimen was measured. The results are shown in FIG. 1, and the dry density increases as the number of tamping increases. On the other hand, the tamped specimen was immersed in a water tank maintained at 80 ° C., and the transition of expansion was measured. FIG. 2 shows the transition of the expansion coefficient of each specimen in this water immersion test. The expansion coefficient increases in the order of decreasing density. That is, the expansion coefficient is 46 times / layer> 92 times / layer> 184 times / layer. In the tamping of the three layers, a sample at the time of tamping only one layer was collected, and the result of the particle size distribution measurement is shown in FIG. 3, and it can be seen that the coarse particles slightly collapsed when the number of tamping times was 184.
以上の結果は、数多く突き固めて多少粒子が壊れたとしても、密度が高くなるように充填させた方が膨張は小さくなることを示している。
その他これまで、加圧蒸気エージング温度を１５８℃から１８３℃（蒸気圧力で０．５ＭＰａ〜０．９５ＭＰａ）、保持時間を２時間から１２時間まで変化させた種々の条件で試験した水浸膨張試験供試体（製鋼スラグ）について乾燥密度と水浸膨張率（ここでは８０℃一定保持で４日後の膨張率で比較）を調べた結果では、乾燥密度が小さい供試体ほど膨張性が大きい傾向があった。
The above results show that the expansion is smaller when the particles are packed so as to have a higher density even if the particles are broken to some extent and broken to some extent.
Others So far, the water vapor expansion test has been conducted under various conditions where the pressurized steam aging temperature is 158 ° C. to 183 ° C. (vapor pressure 0.5 MPa to 0.95 MPa) and the holding time is changed from 2 hours to 12 hours. As a result of examining the dry density and the water immersion expansion rate (in this case, compared with the expansion rate after 4 days at a constant temperature of 80 ° C.) for the test piece (steel slag), the test sample with a lower dry density tended to have a higher expandability. It was.
図４は１５８℃（蒸気圧力：０．５ＭＰａ、保持時間：３±１時間）で加圧蒸気エージングを施した供試体（製鋼スラグ）の乾燥密度と水浸膨張率との関係を、図５は１７３〜１８３℃（蒸気圧力：０．７５〜１．０ＭＰａ、保持時間：３±１時間）で加圧蒸気エージングを施した供試体（製鋼スラグ）の乾燥密度（ＪＩＳ Ａ１２１０（２００９）に定められたＥ−ｂの方法に従い標準９２回／層×３層の突き固めを行って得られた乾燥密度）と水浸膨張率との関係を、それぞれ示しているが、加圧蒸気エージングの温度が異なっても同様の傾向が見られる。 FIG. 4 shows the relationship between the dry density of the specimen (steel slag) subjected to pressurized steam aging at 158 ° C. (steam pressure: 0.5 MPa, holding time: 3 ± 1 hour) and the water immersion expansion rate. Is a dry density (JIS A1210 (2009)) of a specimen (steel slag) subjected to pressurized steam aging at 173 to 183 ° C. (steam pressure: 0.75 to 1.0 MPa, holding time: 3 ± 1 hour) The dry density obtained by tamping the standard 92 times / layer × 3 layers according to the method of Eb) and the water immersion expansion rate are shown respectively. The same tendency can be seen even if the values are different.
一つのスラグ粒子に注目した場合、充填性が高く周囲の粒子からの拘束が大きいと、粒子の亀裂内にある膨張源が反応して膨張し、粒子自体を膨張させようとしても、拘束されて自由には反応が進まない。膨張反応によって粒子をより破壊して亀裂を進展させれば、反応進行中の膨張源や進展した亀裂先端にある未反応膨張源に水分が到達する空間が広げられる。しかし、粒子周辺の拘束が強いと、水分を膨張源に供給するための空間を容易には広げられず、結果として、膨張反応が抑制される。 When focusing on one slag particle, if the filling property is high and the constraint from surrounding particles is large, the expansion source in the crack of the particle reacts and expands, and even if it tries to expand the particle itself, it is restrained. The reaction does not proceed freely. If the particle is further destroyed by the expansion reaction and the crack is advanced, the space in which moisture reaches the expansion source during the reaction and the unreacted expansion source at the advanced crack tip is expanded. However, if the constraint around the particles is strong, the space for supplying moisture to the expansion source cannot be easily expanded, and as a result, the expansion reaction is suppressed.
製鋼スラグの密度を高めるには、粗粒が密に配列し、粗粒間に生じる空隙を細粒が埋め、さらに微粉が細粒間に残る空隙を埋めていくのが望ましい。しかし、空隙を埋めるのに必要以上の細粒、微粉があれば、細粒どうしが接して小さな空隙を多数生じるために、結局、最密な充填からは離れていく。加圧蒸気エージングを長くしても、細粒が必要以上に増えてしまえば、スラグ粒子のパッキングを悪化させて、膨張率の低減化を妨げる。 In order to increase the density of the steelmaking slag, it is desirable to arrange the coarse particles densely, fill the voids formed between the coarse particles with fine particles, and further fill the voids where fine powder remains between the fine particles. However, if there are more fine particles or fine powder than necessary to fill the voids, the fine particles come into contact with each other to form a large number of small voids. Even if the pressurized steam aging is lengthened, if the fine particles increase more than necessary, the packing of the slag particles is deteriorated and the reduction of the expansion rate is hindered.
加圧蒸気エージングを施した種々の製鋼スラグの粒度分布について調べたところ、粒度分布にかなりの差があることが判った。
連続粒度分布の表現についてAndreasenの曲線式があり、最大粒径（Ｄｐmax）に対して各中間径（Ｄｐ）での通過質量分率についてFuller指数ｑを用いて下記（1）式のように表す。
Ｕ（Ｄｐ）＝（Ｄｐ／Ｄｐmax）ｑ …（1）
ここで、Ｄｐは粒径、Ｄｐmaxは最大粒径、Ｕ（Ｄｐ）は粒径Ｄｐまでの通過質量分率である。（出典：例えば「三輪茂雄、粉体工学、日刊工業新聞社、1981年、p.42」）
このAndreasenの曲線は図６のような積算分布になり、細かい粒子が多いほどFuller指数ｑは小さい値となる。実験的には、疎充填ではｑ＝１／２で、密充填ではｑ＝１／３で、それぞれ最も密度が高くなるとされている。
When the particle size distribution of various steelmaking slags subjected to pressurized steam aging was examined, it was found that there was a considerable difference in the particle size distribution.
There is Andreasen's curve formula for the expression of the continuous particle size distribution, and the passing mass fraction at each intermediate diameter (Dp) with respect to the maximum particle diameter (Dpmax) is expressed as the following formula (1) using the Fuller index q. .
U (Dp) = (Dp / Dpmax) q (1)
Here, Dp is the particle size, Dpmax is the maximum particle size, and U (Dp) is the passing mass fraction up to the particle size Dp. (Source: For example, “Shigeo Miwa, Powder Engineering, Nikkan Kogyo Shimbun, 1981, p. 42”)
This Andreasen curve has an integrated distribution as shown in FIG. 6, and the smaller the number of fine particles, the smaller the Fuller index q. Experimentally, q = 1/2 for sparse filling and q = 1/3 for dense filling, and the density is highest.
最大粒径ＤｐmaxとFuller指数ｑを変数として、加圧蒸気エージングを施した種々の製鋼スラグ試料の粒度分布をAndreasenの曲線式で近似した。各試料の突き固め時の乾燥密度（ＪＩＳ Ａ１２１０（２００９）に定められたＥ−ｂの方法に従い標準９２回／層×３層の突き固めを行って得られた乾燥密度）とFuller指数ｑの関係を図７に示す。図７によれば、乾燥密度はｑが０．４〜０．６で最大となり、その前後は小さくなる傾向がある。細粒・微粉が増えるとｑは０．４を下回って、乾燥密度が小さくなる。逆にｑが０．６を上回るのは細粒・微粉を試験的に低減した水準であるが、やはり乾燥密度が小さい。これはｑに充填に最適な範囲があるということであり、Andreasenの曲線式の傾向にも合致している。 Using the maximum particle size Dpmax and the Fuller index q as variables, the particle size distribution of various steelmaking slag samples subjected to pressurized steam aging was approximated by Andreasen's curve formula. The dry density at the time of tamping each sample (dry density obtained by tamping of 92 times / layer × 3 layers in accordance with the method of Eb defined in JIS A1210 (2009)) and the Fuller index q The relationship is shown in FIG. According to FIG. 7, the dry density becomes maximum when q is 0.4 to 0.6, and tends to be small before and after that. When fine particles and fine powder increase, q falls below 0.4 and the dry density decreases. On the other hand, q exceeds 0.6 at a level where the fine particles and fine powder were experimentally reduced, but the dry density is still small. This means that q has an optimum range for filling, and is consistent with the tendency of Andreasen's curve formula.
製鋼スラグの実際の破砕プラントにおいて、単純に破砕過程及び分級した粗粒の再破砕を経た製品では、細粒・微粉が例えば鉄鋼スラグ路盤材のＪＩＳ規格（ＪＩＳ Ａ５０１５）に照らして必要より少ないことはあまりなく、概ね細かく砕きすぎる場合が多いと考えられる。
さきに挙げた図７において乾燥密度が小さく、膨張が大きかった水準は殆んどｑが０．４未満である。ちなみに１５８℃（蒸気圧力０．５ＭＰａ）で加圧蒸気エージングを施した製鋼スラグの水浸膨張率（８０℃一定保持で４日後の膨張率）とFuller指数ｑとの関係をみると、図８に示すようにｑ＝０．５に向かって水浸膨張率が低下している。
In an actual crushing plant for steelmaking slag, products that have undergone crushing process and re-crushing coarse particles that have been classified should have less fines and fines than necessary in light of the JIS standard for steel slag roadbed materials (JIS A5015). There are not so many, and it is thought that there are many cases where it is crushed finely.
In the above-mentioned FIG. 7, the level at which the dry density is small and the expansion is large is that q is less than 0.4. Incidentally, the relationship between the water immersion expansion rate (expansion rate after 4 days at a constant hold of 80 ° C.) and the Fuller index q of steelmaking slag subjected to pressurized steam aging at 158 ° C. (steam pressure 0.5 MPa) is shown in FIG. As shown in FIG. 6, the water expansion coefficient decreases toward q = 0.5.
Fuller指数ｑが０．６より大きくなると、粗粒どうしが接触する頻度が高くなり、粗粒間の空隙を埋める細粒が不足して、充填性が低下する。この場合も粒子間の拘束が低くなり、膨張崩壊をより自由に進められる環境になる。さらに、粗粒ばかりの場合は、ＪＩＳ Ａ５０１５に規定された水浸膨張試験で、試料粒子を型枠の中に突き固める際に、ランマの衝撃を粗粒が直接受ける確率が増し、かつ粗粒に接触している粒子が低充填で少ないため、周囲に応力を分散できなくなって、衝撃を受けた粗粒が高頻度で崩壊する。そうすると、新しい破面に未反応の膨張源が出現するため、加圧蒸気エージングしたにも拘わらず、水浸膨張試験前に多くの未反応膨張源が反応しやすい状況となって、水浸膨張率を上昇させることになる。したがって、粒度を単純に粗粒化すればよい訳でもない。 When the Fuller index q is larger than 0.6, the frequency with which the coarse particles come into contact with each other increases, and the fine particles that fill the gaps between the coarse particles are insufficient, thereby reducing the filling property. Also in this case, the constraint between the particles becomes low, and an environment in which expansion and collapse can be promoted more freely. Furthermore, in the case of only coarse particles, the probability that the coarse particles are directly subjected to the impact of the Ranma increases when the sample particles are solidified in the mold by the water immersion expansion test specified in JIS A5015. Since there are few particles in contact with the filler, the stress cannot be dispersed to the surroundings, and the impacted coarse particles are frequently broken down. As a result, an unreacted expansion source appears on the new fracture surface, so that despite the aging of pressurized steam, many unreacted expansion sources are likely to react before the water immersion expansion test. Will increase the rate. Therefore, it is not necessary to simply coarsen the particle size.
以上のことから、本発明者は、加圧蒸気エージングを施した製鋼スラグの水浸膨張は粒度分布によっても影響を受けており、粒度分布が不適切であるためにスラグ粒子の充填性が低下すると、水浸膨張が増大していることを見出した。したがって、望まれる加圧蒸気エージングを実施しても、粒度分布が不適切であることによって膨張性が不合格判定になることが相当数起こっているものと考えられる。特に加圧蒸気エージングでは、高温で膨張反応を短時間で促進して、反応し得る膨張源を極力反応させきることを志向するので、膨張崩壊によって細粒・微粉分が増大しやすく、粒度分布が不適切になりやすい。 From the above, the present inventor found that the water immersion expansion of steelmaking slag subjected to pressurized steam aging is also affected by the particle size distribution, and the particle size distribution is inadequate, so the slag particle filling ability is reduced. Then, it discovered that water immersion expansion was increasing. Therefore, even if the desired pressurized steam aging is performed, it is considered that a considerable number of cases where the expansibility is judged to be rejected due to an inappropriate particle size distribution. In particular, in pressurized steam aging, the expansion reaction is accelerated at high temperatures in a short time and the expansion source capable of reacting is intended to react as much as possible. Tends to be inappropriate.
本発明者は、上記知見に基づきさらに検討を進めた結果、所定の条件で事前に細粒・微粉分を増減した製鋼スラグを加圧蒸気エージングすれば、適用したエージング条件で到達し得る最小の膨張率の路盤材が得られることが判った。具体的には、Fuller指数ｑが０．４〜０．６となるように粒度分布を調整することが望ましいことが判った。この方法によれば、加圧蒸気エージング前の製鋼スラグの細粒・微粉分を増減するだけでよいため、膨張性が極めて低い製鋼スラグ路盤材を高い生産性で製造することができ、また、製造される製鋼スラグ路盤材は、密度が高いため締め固め性にも優れている。 As a result of further investigation based on the above knowledge, the present inventor has determined that the minimum achievable under the applied aging conditions if the steam aging is applied to the steelmaking slag whose fine particles and fines have been increased or decreased in advance under the predetermined conditions. It was found that a roadbed material having an expansion rate can be obtained. Specifically, it has been found desirable to adjust the particle size distribution so that the Fuller index q is 0.4 to 0.6. According to this method, it is only necessary to increase / decrease the fine particles / fine powder content of the steelmaking slag before pressurized steam aging, so it is possible to produce a steelmaking slag roadbed material with extremely low expansibility with high productivity, The manufactured steelmaking slag roadbed material is excellent in compaction because of its high density.
このため本発明では、粒径４０ｍｍ以下の割合が８０mass％以上となる粒度に破砕された製鋼スラグ（以下、説明の便宜上「製鋼スラグａ」という）について、下記（ｉ）又は（ii）の条件で細粒・微粉分を増減することにより、製鋼スラグａの粒度分布をAndreazenの曲線式で近似した場合に、Fuller指数が０．４〜０．６となるように製鋼スラグａの粒度分布を調整した後、加圧蒸気エージングを施すようにする。なお、粒径４０ｍｍ以下とは篩目が４０ｍｍ（呼び径）の篩を通過する粒径である。
（ｉ）製鋼スラグａの一部について篩目が１０ｍｍ以下の篩（以下、説明の便宜上「篩ｘ」という）で分級することで細粒・微粉分を減じた後、製鋼スラグａの残部（有姿粒度の製鋼スラグａ）と混合する。
（ii）以前に、粒径４０ｍｍ以下の割合が８０mass％以上となる粒度に破砕された製鋼スラグを篩目が１０ｍｍ以下の篩ｘで分級することで得られている細粒・微粉分を、製鋼スラグａ（有姿粒度の製鋼スラグａ）に加えて混合する。
なお、上記（ii）の「以前に・・得られている細粒・微粉分」とは、以前に行われた分級において得られ、ストックされている細粒・微粒分のことである。
製鋼スラグは、鉄鋼製造プロセスの製鋼工程で発生するスラグであり、脱炭スラグ（転炉脱炭スラグ）、溶銑予備処理スラグ（脱珪スラグ、脱燐スラグなど）、造塊スラグ、溶融還元スラグ、電気炉スラグなどがあり、これらの１種以上を用いることができる。
Therefore, in the present invention, the steelmaking slag (hereinafter referred to as “steelmaking slag a” for convenience of description) crushed to a particle size in which the ratio of the particle size of 40 mm or less is 80 mass% or more is the following condition (i) or (ii) The particle size distribution of the steelmaking slag a is adjusted so that the Fuller index is 0.4 to 0.6 when the particle size distribution of the steelmaking slag a is approximated by Andreazen's curve formula by increasing or decreasing the fine grain / fine powder content. After adjustment, pressurized steam aging is performed. The particle size of 40 mm or less is a particle size that passes through a sieve having a sieve mesh of 40 mm (nominal diameter).
(I) A part of the steelmaking slag a is classified by a sieve having a sieve mesh of 10 mm or less (hereinafter referred to as “sieve x” for convenience of explanation) to reduce fine particles and fine powder, and then the remainder of the steelmaking slag a ( Mix with solid grain steelmaking slag a).
(Ii) Fine particles and fine powder obtained by classifying steelmaking slag previously crushed into a particle size with a particle size of 40 mm or less being 80 mass% or more with a sieve x having a mesh size of 10 mm or less, In addition to steelmaking slag a (steelmaking slag a having a solid particle size), it is mixed.
The “previously obtained fine particles / fine powder” in (ii) above refers to the fine particles / fine particles obtained and classified in the previous classification.
Steelmaking slag is slag generated in the steelmaking process of the steel production process, including decarburization slag (converter decarburization slag), hot metal pretreatment slag (desiliconization slag, dephosphorization slag, etc.), ingot slag, smelting reduction slag There are electric furnace slags, and one or more of these can be used.
本発明において、細粒・微粉分の増減により粒度分布を調整する前の製鋼スラグａについて、その８０mass％以上を占めるスラグの最大粒径を４０ｍｍとしたのは、それより大きい径では内部に残留する膨張源が増加するため、加圧蒸気エージングを施しても水浸膨張率のバラツキが大きくなり、膨張性が安定化しないためである。
Andreazenの曲線式で積算篩下の曲線が大きく変化するのは、Fuller指数ｑが１より小さい領域では粒径が最大粒径の２０％以下の部分と考えられる。篩目４０ｍｍで８０mass％以上通過する粒度分布であれば、最大粒径の２０％の粒径は実質的に１０ｍｍとなり、それ以下の細粒・微粉分の粒子量を調整することが望ましい。このため本発明では、上記（ｉ）、（ii）のように篩目が１０ｍｍ以下の篩ｘで分級することを通じて細粒・微粉分を増減し、粒度分布を調整する。
In the present invention, regarding steelmaking slag a before adjusting the particle size distribution by increasing / decreasing fine particles / fine powder, the maximum particle size of slag occupying 80 mass% or more is set to 40 mm. This is because the number of expansion sources to be increased increases, and even when pressurized steam aging is performed, the variation in the water immersion expansion rate increases, and the expandability is not stabilized.
It is considered that the curve under the integrated sieve greatly changes in Andreazen's curve formula in a region where the particle size is 20% or less of the maximum particle size in the region where the Fuller index q is smaller than 1. If the particle size distribution passes 80 mass% or more at a mesh size of 40 mm, the particle size of 20% of the maximum particle size is substantially 10 mm, and it is desirable to adjust the amount of fine particles and fine powder below that. For this reason, in the present invention, as in (i) and (ii) above, the fine particle / fine powder content is increased / decreased through classification with a sieve x having a sieve mesh of 10 mm or less, and the particle size distribution is adjusted.
また、望まれるFuller指数ｑ１／２近傍では変化が大きいのは最大粒径の１０％以下（約５ｍｍ以下）の部分であり、直接的に５ｍｍ以下の粒子を増減することが粒度分布を操作しやすい。このため本発明では、上記（ｉ）、（ii）の篩ｘの篩目を５ｍｍ（呼び径）とし、その篩目を通過する粒径５ｍｍ以下の細粒・微粉分の増減を行うことが好ましい（なお、以下の説明において「粒径５ｍｍ以下」、「−５ｍｍ」とは篩目５ｍｍ（呼び径）を通過する粒径のことである。）。すなわち、上記（ｉ）のように細粒・微粉分を減じる場合には、例えば、対象となる製鋼スラグａの山（同日に同じ精錬設備で発生した製鋼スラグ）の一部だけ篩目が５ｍｍ（呼び径）の篩ｘで分級することで粒径５ｍｍ以下の粒子を分離し、残りの山の部分（製鋼スラグａの残部）は分級することなく有姿粒度のままとし、分級した製鋼スラグａと分級しない有姿粒度のままの製鋼スラグａを混合する。この場合、篩目が５ｍｍの篩ｘで分級する製鋼スラグａの割合を変えることで、全体での粒径５ｍｍ以下の細粒・微粉分の割合を調整できる。一方、５ｍｍ以下の粒子が不足し、上記（ii）のように不足する細粒・微粉分を増やす場合には、それ以前の分級で篩い出したストックの−５ｍｍ分（粒径４０ｍｍ以下の割合が８０mass％以上となる粒度に破砕された製鋼スラグを篩目が５ｍｍ（呼び径）の篩ｘで分級して得られている細粒・微粉分）を必要なだけ加え、混合する。そして、以上のような粒度分布の調整により、Fuller指数ｑが０．４〜０．６となるようにする。
製鋼スラグのなかでも脱炭スラグは、比較的高塩基度（ＣａＯ／ＳｉＯ２）で、遊離ＣａＯの含有量も高いことから、粒径５ｍｍ以下のスラグ粒子は、例えば焼結原料や精錬の造滓材にリサイクル使用することもできるため、積極的に分級して取り出す利点も有している。
In addition, the portion where the change is large in the vicinity of the desired Fuller index q1 / 2 is a portion of 10% or less (about 5 mm or less) of the maximum particle size, and directly increasing or decreasing the particle size of 5 mm or less manipulates the particle size distribution. Cheap. Therefore, in the present invention, the sieve x of the sieves (i) and (ii) is set to 5 mm (nominal diameter), and the fine and fine particles having a particle diameter of 5 mm or less that pass through the sieve can be increased or decreased. (In the following description, “particle size of 5 mm or less” and “−5 mm” are particle sizes that pass through a mesh size of 5 mm (nominal diameter)). That is, when reducing the fine particles and fines as in (i) above, for example, only a part of the target steelmaking slag a pile (steeling slag generated in the same refining equipment on the same day) has a mesh size of 5 mm. Particles with a particle size of 5 mm or less are separated by classification with (nominal diameter) sieve x, and the remaining mountain parts (the remainder of the steelmaking slag a) are left as they are without classification, and classified steelmaking slag. a and steelmaking slag a which is not classified and which has a solid particle size are mixed. In this case, by changing the ratio of the steelmaking slag a classified by the sieve x having a sieve mesh of 5 mm, the ratio of fine particles / fine powder having a particle diameter of 5 mm or less as a whole can be adjusted. On the other hand, when there are insufficient particles of 5 mm or less and the amount of fine particles and fines to be insufficient is increased as in (ii) above, -5 mm of the stock screened by the previous classification (ratio of particle size of 40 mm or less) Is added to the steelmaking slag crushed to a particle size of 80 mass% or more with a sieve x having a mesh size of 5 mm (nominal diameter) as much as necessary, and mixed. Then, by adjusting the particle size distribution as described above, the Fuller index q is set to 0.4 to 0.6.
Among steelmaking slag, decarburized slag has a relatively high basicity (CaO / SiO 2 ) and a high content of free CaO. Therefore, slag particles having a particle size of 5 mm or less are used for, for example, sintering raw materials and refining. Since it can be recycled for use as a firewood, it also has the advantage of being actively classified and extracted.
製鋼スラグ路盤材には２種以上の製鋼スラグを混合して用いることも可能である。このように製鋼スラグａが２種以上の製鋼スラグからなる場合には、そのなかの１種の製鋼スラグａ1の全部又は一部について篩目が１０ｍｍ以下の篩ｘ（例えば、篩目が呼び径５ｍｍの篩ｘ）で分級することで細粒・微粉分を減じた後、分級しない有姿粒度のままの残りの１種以上の製鋼スラグａ2及び製鋼スラグａ1の残部（但し、製鋼スラグａ1の全部を上記分級した場合を除く。）と混合することにより粒度分布を調整するようにしてもよい。この場合、（1）篩目が１０ｍｍ以下の篩ｘ（例えば、篩目が呼び径５ｍｍの篩ｘ）で分級する製鋼スラグａ1の割合を変えること、（2）製鋼スラグａ1と製鋼スラグａ2の量比を変えること、のいずれか又は両方により、全体での粒径５ｍｍ以下の細粒・微粉分の割合を調整できる。そして、以上のような粒度分布の調整により、Fuller指数ｑが０．４〜０．６となるようにする。
上記のように製鋼スラグ路盤材に２種以上の製鋼スラグを混合して用いる場合の代表例は、製鋼スラグａ1が同日に同じ精錬設備で発生した脱炭スラグであり、製鋼スラグａ2が脱炭スラグ以外の製鋼スラグである場合である。
Two or more kinds of steelmaking slag can be mixed and used for the steelmaking slag roadbed material. Thus, when the steelmaking slag a consists of two or more types of steelmaking slag, a sieve x having a sieve size of 10 mm or less (for example, the sieve mesh is the nominal diameter) of all or a part of one type of the steelmaking slag a1. After the fine particles and fines are reduced by classification with a 5 mm sieve x), the remaining one or more types of steelmaking slag a2 and the remainder of the steelmaking slag a1 remain in the solid particle size not classified (however, the steelmaking slag a1 The particle size distribution may be adjusted by mixing with the above). In this case, (1) changing the ratio of the steelmaking slag a1 classified by a sieve x having a sieve mesh of 10 mm or less (for example, a sieve x having a nominal diameter of 5 mm), (2) the steelmaking slag a1 and the steelmaking slag a2 The ratio of fine particles / fine powder having a particle size of 5 mm or less as a whole can be adjusted by either or both of changing the quantitative ratio. Then, by adjusting the particle size distribution as described above, the Fuller index q is set to 0.4 to 0.6.
A typical example of using two or more types of steelmaking slag mixed with steelmaking slag roadbed material as described above is decarburization slag generated in the same refining equipment on the same day, and steelmaking slag a2 is decarburized. This is the case of steelmaking slag other than slag.
本発明において、Fuller指数ｑが０．４〜０．６となるように粒度分布を調整するのは加圧蒸気エージング前の製鋼スラグａである。製鋼スラグａの粒度は、加圧蒸気エージングを施すと細粒・微粉が増えるが、同時に粗粒が低減することによりAndreasenの曲線式における最大粒径が低下するので、粒度分布の形はさほど変化しない。このため加圧蒸気エージングを施した後の製鋼スラグａ（路盤材製品）のFuller指数ｑも概ね０．４〜０．６の範囲に維持される。但し、加圧蒸気エージングにより全体的には細粒化するにもかかわらず、最大粒径が低下することにより、Fuller指数が増大することもある。このため、望ましくはFuller指数ｑが０．５近傍（０．５±０．０５）となるように粒度分布を調整した上で、加圧蒸気エージングすることがより好ましい。 In the present invention, it is the steelmaking slag a before pressurized steam aging that adjusts the particle size distribution so that the Fuller index q is 0.4 to 0.6. The grain size of steelmaking slag a increases with fine steam and fine powder when subjected to pressurized steam aging, but at the same time, the reduction of coarse grains reduces the maximum grain size in Andreasen's curve formula, so the shape of the grain size distribution changes greatly. do not do. For this reason, the Fuller index q of the steelmaking slag a (roadbed material product) after being subjected to pressurized steam aging is also generally maintained in the range of 0.4 to 0.6. However, the fuller index may increase due to a decrease in the maximum particle diameter despite the fact that the whole is fined by pressurized steam aging. For this reason, it is more preferable to perform pressurized steam aging after adjusting the particle size distribution so that the Fuller index q is approximately 0.5 (0.5 ± 0.05).
上述したスラグの混合、すなわち、分級した製鋼スラグａと分級しない有姿粒度のままの製鋼スラグａの混合や、製鋼スラグａ1と製鋼スラグａ2の混合は、加圧蒸気エージング前に行う必要がある。加圧蒸気エージング後に重機や混合機を用いてスラグ粒子を均一に混合しようとすると、スラグ粒子に機械的応力が作用して、再度崩壊したり、膨張反応が終了した粒子表面を引っ掻いたり、削ったりして未反応膨張源を出現させる。その結果、水浸膨張率が上昇したり、バラツキが大きくなり、製品として不合格判定となる比率が増大する。 Mixing of the slag mentioned above, that is, mixing of the classified steelmaking slag a and the unclassified steelmaking slag a, and mixing of the steelmaking slag a1 and the steelmaking slag a2 must be performed before pressurized steam aging. . When trying to mix slag particles uniformly using heavy machinery or a mixer after pressurized steam aging, mechanical stress acts on the slag particles, causing them to collapse again, scratching or scraping the particle surface after the expansion reaction has ended. Or unreacted expansion sources appear. As a result, the water immersion expansion rate increases, the variation increases, and the proportion of products that are rejected increases.
加圧蒸気エージングの圧力は製鋼スラグ中の遊離ＣａＯや遊離ＭｇＯの量に応じて調整することができる。量が多いほど、反応しうる状態にある遊離ＣａＯや遊離ＭｇＯを迅速に反応させる必要があり、温度を高くし飽和蒸気圧を上昇させた方が有利である。飽和蒸気圧を１．９６ＭＰａを超えるレベルにすると、蒸気供給設備や圧力容器が処理量に較べて大規模になり、不経済である。一方、飽和蒸気圧が０．２０ＭＰａ未満では飽和蒸気圧温度が低くなり、大気圧下で平衡する１００℃の蒸気に対しての反応促進効果が小さくなる。このため、蒸気圧は０．２０〜１．９６ＭＰａが好ましい。 The pressure of pressurized steam aging can be adjusted according to the amount of free CaO and free MgO in the steelmaking slag. The larger the amount, the faster it is necessary to react free CaO or free MgO in a reactive state, and it is advantageous to raise the temperature and raise the saturated vapor pressure. If the saturated vapor pressure is set to a level exceeding 1.96 MPa, the steam supply equipment and the pressure vessel become larger than the processing amount, which is uneconomical. On the other hand, when the saturated vapor pressure is less than 0.20 MPa, the saturated vapor pressure temperature is low, and the reaction promoting effect on the vapor at 100 ° C. that is balanced under atmospheric pressure is small. For this reason, the vapor pressure is preferably 0.20 to 1.96 MPa.
加圧蒸気エージングの処理時間（保持時間）は１〜５時間程度が適当である。処理時間（保持時間）の望ましい上限を５時間としたのは、処理時間が長すぎると生産性が低下し、加圧蒸気による反応促進の優位性がなくなり、１００℃の蒸気で１０００Ｔ規模の蒸気エージングを実施するのと同程度となってしまうからである。このため、蒸気温度を上昇させて保持時間を短縮することが望ましい。また、処理時間（保持時間）の望ましい下限を１時間としたのは、圧力容器内のスラグが均一に昇温して反応促進するには、最低でも１時間は必要だからである。 The treatment time (holding time) for pressurized steam aging is suitably about 1 to 5 hours. The desirable upper limit of the treatment time (holding time) is set to 5 hours. If the treatment time is too long, the productivity is lowered, and the advantage of promoting the reaction by pressurized steam is lost. This is because it becomes the same level as aging. For this reason, it is desirable to shorten the holding time by raising the steam temperature. Further, the reason why the desirable lower limit of the processing time (holding time) is set to 1 hour is that at least 1 hour is required for the slag in the pressure vessel to uniformly raise the temperature and promote the reaction.
本発明法において加圧蒸気エージングした後の製鋼スラグの粒度は、ＪＩＳ Ａ５０１５（２０１３）に粒度範囲が定められているＣＳ−４０、ＣＳ−３０、ＣＳ−２０、ＭＳ−２５、ＨＭＳ−２５のいずれかの粒度範囲を満足することが好ましい。これらは道路用鉄鋼スラグの粒度を含めた物性を規定したものであり、規格名の数字は概ねの最大粒径を示している。実用上はこの粒度を満たすものが道路舗装工事に用いられるため、路盤材用途の販売にはこの規格に合格する必要がある。
以上のような本発明法で製造される製鋼スラグ路盤材は、粒度分布をAndreazenの曲線式で近似した場合に、Fuller指数が０．４〜０．６となる粒度分布を有することが好ましい。
本発明により製造された製鋼スラグ路盤材は、単独で使用（施工）してもよいし、他の路盤材料（例えば、他のスラグ路盤材や砕石など）と混合して使用（施工）してもよい。
The particle size of steelmaking slag after pressurized steam aging in the method of the present invention is that of CS-40, CS-30, CS-20, MS-25, HMS-25 whose particle size ranges are defined in JIS A5015 (2013). It is preferable to satisfy any particle size range. These stipulate the physical properties including the grain size of steel slag for roads, and the numbers in the standard names indicate the approximate maximum grain size. In practice, those satisfying this granularity are used for road paving work, so it is necessary to pass this standard to sell roadbed materials.
The steelmaking slag roadbed material manufactured by the method of the present invention as described above preferably has a particle size distribution with a Fuller index of 0.4 to 0.6 when the particle size distribution is approximated by an Andreazen curve formula.
The steelmaking slag roadbed material manufactured according to the present invention may be used (constructed) alone, or used (constructed) by mixing with other roadbed materials (for example, other slag roadbed materials and crushed stones). Also good.
原料となる製鋼スラグは、脱炭スラグと造塊スラグであり、いずれも粒径４０ｍｍ以下に破砕されたもの（篩目４０ｍｍ（呼び径）の篩を通過したもの）である。遊離ＣａＯ含有量は、脱炭スラグが４．９〜５．２mass％、造塊スラグが１．３mass％であった。実施例１及び実施例２では、脱炭スラグとして、篩目が５ｍｍ（呼び径）の篩で−５ｍｍの粒子を分級・排除したスラグＡ（粒度５−４０ｍｍ）と、このスラグＡと同日に同じ精錬設備で発生した脱炭スラグであって、分級せずに−５ｍｍの粒子をそのまま含む有姿粒度のスラグＢ（粒度０−４０ｍｍ）を用いた。また、実施例２では、造塊スラグとして、分級せずに−５ｍｍの粒子をそのまま含む有姿粒度のスラグＣ（粒度０−４０ｍｍ）を用いた。また、実施例３では、脱炭スラグとして、分級されていない有姿粒度のスラグＤ（粒度０−４０ｍｍ）と、以前に、粒径４０ｍｍ以下に破砕された脱炭スラグを篩目が５ｍｍ（呼び径）の篩で分級した際に篩下となり、ストックされていたスラグＥ（粒度０−５ｍｍ）を用いた。なお、スラグＤは粒度０−４０ｍｍであるが、全体的に粒度が粗く、細粒分が少ない粒度分布のスラグである。
スラグＡ〜Ｅのうちの２つのスラグを混合する際には、スラグの混合にホイルローダー等の重機を用い、切り返しを数度繰り返すことで混合を均一化した。
Steelmaking slag used as a raw material is decarburized slag and ingot slag, both of which are crushed to a particle size of 40 mm or less (passed through a sieve having a sieve size of 40 mm (nominal diameter)). The free CaO content was 4.9 to 5.2 mass% for decarburized slag and 1.3 mass% for ingot slag. In Example 1 and Example 2, as decarburized slag, slag A (particle size 5-40 mm) in which particles of -5 mm are classified and eliminated with a sieve having a mesh size of 5 mm (nominal diameter), and the same day as this slag A Decarburized slag generated in the same refining equipment was used, and slag B (particle size 0-40 mm) having a solid particle size containing -5 mm particles as they were without classification. In Example 2, slag C having a solid particle size (particle size of 0 to 40 mm) containing -5 mm particles as they were without classification was used as the ingot slag. Moreover, in Example 3, as the decarburized slag, the solid particle size slag D (particle size 0-40 mm) that has not been classified and the decarburized slag previously crushed to a particle size of 40 mm or less have a mesh size of 5 mm ( The slag E (particle size 0-5 mm) that was under-sieved when classified with a sieve having a nominal diameter) was used. The slag D has a particle size of 0 to 40 mm, but is a slag having a particle size distribution with a coarse particle size overall and a small fine particle content.
When mixing two slags out of the slags A to E, a heavy machine such as a wheel loader was used to mix the slags, and the mixing was made uniform by repeating the turnover several times.
スラグの通過質量分率（粒度分布）を測定するのに、３７．５ｍｍ（呼び径４０ｍｍ）、３１．５ｍｍ、２６．５ｍｍ、１９．０ｍｍ、１３．０ｍｍ、９．５ｍｍ（呼び径１０ｍｍ）、４．７５ｍｍ（呼び径５ｍｍ）、２．３６ｍｍ、１．１８ｍｍ、０．６ｍｍ、０．３ｍｍ、０．１５ｍｍ、０．０７５ｍｍの篩を用いた。この篩系列は、骨材粒度を測定する篩系列とスラグ路盤材の粒度を測定する篩系列の折衷となっている。これは、スラグ路盤材の篩系列よりも細粒側の分布を精密に測定するためである。ＪＩＳ Ａ５０１５（２０１３）道路用鉄鋼スラグでは水浸膨張率を１．５％以下と規定しているが、実操業では製品中のバラツキがあることを考慮して、より小さな膨張率にまで安定化することがよく行われる。本実施例では、加圧蒸気エージング後のスラグ単味で水浸膨張率を０．７％以下にまで低減することを目安とした。
加圧蒸気エージングは、蒸気吹込みにより昇温・昇圧する横置き式のオートクレーブにおいて、蒸気圧力０．９８ＭＰａで３時間保持する条件で実施した。
37.5 mm (
Pressurized steam aging was carried out in a horizontal autoclave where the temperature was increased and increased by blowing steam under the condition that the steam pressure was maintained at 0.98 MPa for 3 hours.
［実施例１］
比較例１を除き、−５ｍｍの細粒分を分級・排除したスラグＡ（粒度５−４０ｍｍ）と、−５ｍｍの細粒分を分級・排除していない有姿粒度のスラグＢ（粒度０−４０ｍｍ）を混合し、所定の粒度分布を有するスラグ（試料）とした。なお、比較例１は、有姿粒度のスラグＢ（粒度０−４０ｍｍ）のみからなるスラグ（試料）を対象とした。これら加圧蒸気エージング前のスラグについて、Andreasenの曲線式におけるFuller指数ｑをグラフソフトの回帰機能を用いて求めた。その一例を図９に示す。その際、通過質量分率１００mass％、すなわち全通となる篩目の通過質量分率はデータとせず、通過質量分率１００mass％未満の篩目での通過質量分率のみをデータとして近似した。
各スラグに対して加圧蒸気エージングを施した後、再度、粒度分布測定とFuller指数ｑの算出を行った。また、加圧蒸気エージング後のスラグについてＪＩＳ Ａ５０１５（２０１３）附属書２に定めた水浸膨張試験を行い、各供試体の乾燥密度と水浸膨張率を測定した。
[Example 1]
Except for Comparative Example 1, slag A (particle size 5-40 mm) in which fine particles of -5 mm were classified / excluded and slag B (solid size 0-) in which -5 mm fine particles were not classified / excluded 40 mm) was mixed to obtain a slag (sample) having a predetermined particle size distribution. In addition, the comparative example 1 was made into the slag (sample) which consists only of slag B (granularity 0-40mm) of solid particle size. For the slag before pressurized steam aging, the Fuller index q in Andreasen's curve equation was determined using the regression function of the graph software. An example is shown in FIG. At that time, the passing mass fraction of 100 mass%, that is, the passing mass fraction of the entire mesh was not used as data, and only the passing mass fraction of the mesh with a passing mass fraction of less than 100 mass% was approximated as data.
After subjecting each slag to pressurized steam aging, the particle size distribution measurement and the calculation of the Fuller index q were performed again. Moreover, the water immersion expansion test defined in JIS A5015 (2013)
それらの結果を表１及び表２に示す。なお、表１及び表２に記載された最大粒径Ｄｐmaxは、各スラグの粒度分布をAndreazenの曲線式で近似したときに、フィッティングした曲線から求まるスラグの最大粒径（スラグが全通となる計算上の篩目）である。表３〜表６に記載された最大粒径Ｄｐmaxについても同様である。
表１及び表２によれば、Fuller指数ｑが０．４〜０．６の範囲にある発明例１〜３は、水浸膨張供試体の乾燥密度が高く、水浸膨張率が比較例に比べて低い。これに対して、Fuller指数ｑが０．４より小さい比較例１、２と、Fuller指数ｑが０．６より大きい比較例３、４では、発明例と同じ由来のスラグであっても水浸膨張率は高い。
The results are shown in Tables 1 and 2. The maximum particle size Dpmax described in Tables 1 and 2 is the maximum particle size of slag obtained from the fitted curve when the particle size distribution of each slag is approximated by Andreazen's curve formula (the slag is all through). (Sieving in calculation). The same applies to the maximum particle size Dpmax described in Tables 3 to 6.
According to Table 1 and Table 2, Invention Examples 1-3 in which the Fuller index q is in the range of 0.4 to 0.6 have a high dry density of the water immersion expansion specimen, and the water expansion coefficient is in the comparative example. Low compared. On the other hand, in Comparative Examples 1 and 2 in which the Fuller index q is less than 0.4 and in Comparative Examples 3 and 4 in which the Fuller index q is greater than 0.6, even if the slag is the same as that of the inventive example, The expansion rate is high.
［実施例２］
脱炭スラグであるスラグＡ（粒度５−４０ｍｍ）又はスラグＢ（粒度０−４０ｍｍ）と、造塊スラグであるスラグＣ（粒度０−４０ｍｍ）を混合し、所定の粒度分布を有するスラグ（試料）とした。これら加圧蒸気エージング前のスラグについて、実施例１と同様の方法でFuller指数ｑを求めた。また、各スラグに対して加圧蒸気エージングを施した後、実施例１と同様の方法で粒度分布測定とFuller指数ｑの算出を行うとともに、各供試体の乾燥密度と水浸膨張率を測定した。
また、比較のためにスラグＡ、スラグＢ、スラグＣにそれぞれ単味で加圧蒸気エージングを施し、同様にエージング処理後の粒度分布測定とFuller指数ｑの算出を行うとともに、各供試体の乾燥密度と水浸膨張率を測定した。
[Example 2]
A slag having a predetermined particle size distribution by mixing slag A (particle size 5-40 mm) or slag B (particle size 0-40 mm) as decarburized slag and slag C (particle size 0-40 mm) as ingot slag. ). With respect to the slag before pressurized steam aging, the Fuller index q was determined in the same manner as in Example 1. In addition, after subjecting each slag to pressurized steam aging, the particle size distribution measurement and fuller index q are calculated in the same manner as in Example 1, and the dry density and water expansion coefficient of each specimen are measured. did.
For comparison, slag A, slag B, and slag C are each subjected to simple pressurized steam aging, and similarly, the particle size distribution after aging treatment and the calculation of the fuller index q are calculated, and each specimen is dried. The density and water expansion coefficient were measured.
それらの結果を表３及び表４に示す。これによれば、−５ｍｍの細粒分を分級・排除していない有姿粒度のスラグＢ（粒度０−４０ｍｍ）とスラグＣ（粒度０−４０ｍｍ）を７０：３０（質量比）で混合した比較例５はFuller指数ｑが０．４より小さい。一方、−５ｍｍの細粒分を分級・排除したスラグＡ（粒度５−４０ｍｍ）とスラグＣ（粒度０−４０ｍｍ）を５０：５０（質量比）で混合した発明例４はFuller指数ｑが０．４〜０．６の範囲内にある。ここで、スラグＡ、Ｂ、Ｃをそれぞれ単味で使用した場合をみると、スラグＣは遊離ＣａＯが少ないために、膨張安定化が速やかに起こり、加圧蒸気エージング後の水浸膨張率は０．２３％と低い。一方、脱炭スラグであるスラグＡとスラグＢは元々遊離ＣａＯ量がスラグＣよりも多く、またFuller指数ｑはともに０．４〜０．６の範囲から外れており、供試体の乾燥密度が低く、水浸膨張率は０．７％よりも高い。発明例４の場合、供試体の乾燥密度が高く、水浸膨張率はスラグＢとスラグＣの水浸膨張率平均より低い値となっており、粒度分布の調整による効果が現れている。 The results are shown in Tables 3 and 4. According to this, slag B (granularity 0-40 mm) and solid slag C (granularity 0-40 mm) having a fine particle size of -5 mm not classified / excluded were mixed at 70:30 (mass ratio). In Comparative Example 5, the Fuller index q is less than 0.4. On the other hand, Invention Example 4 in which slag A (particle size 5-40 mm) and slag C (particle size 0-40 mm) obtained by classifying and eliminating a fine particle portion of -5 mm was mixed at 50:50 (mass ratio) had a Fuller index q of 0. Within the range of 4-0.6. Here, when slags A, B, and C are used in a simple manner, since slag C has little free CaO, expansion stabilization occurs quickly, and the water immersion expansion rate after pressurized steam aging is As low as 0.23%. On the other hand, slag A and slag B, which are decarburized slags, originally have more free CaO than slag C, and the Fuller index q is both out of the range of 0.4 to 0.6, and the dry density of the specimen is Low, the water expansion coefficient is higher than 0.7%. In the case of Invention Example 4, the dry density of the specimen is high, the water expansion coefficient is lower than the average water expansion coefficient of slag B and slag C, and the effect of adjusting the particle size distribution appears.
[実施例３]
いずれも脱炭スラグである有姿粒度のスラグＤ（粒度０−４０ｍｍ）と篩目５ｍｍの篩下のスラグＥ（粒度０−５ｍｍ）を混合し、所定の粒度分布を有するスラグ（試料）とした。この加圧蒸気エージング前のスラグについて、実施例１と同様の方法でFuller指数ｑを求めた。また、スラグに対して加圧蒸気エージングを施した後、実施例１と同様の方法で粒度分布測定とFuller指数ｑの算出を行うとともに、供試体の乾燥密度と水浸膨張率を測定した。
また、比較のためにスラグＤ単味について、実施例１と同様の方法でFuller指数ｑを求めた。さらに、スラグＤ単味で加圧蒸気エージングを施し、同様にエージング処理後の粒度分布測定とFuller指数ｑの算出を行うとともに、乾燥密度と水浸膨張率を測定した。
[Example 3]
Any of the decarburized slag is a slag (sample) having a predetermined particle size distribution by mixing solid slag D (particle size 0-40 mm) and slag E (particle size 0-5 mm) under a sieve size of 5 mm. did. With respect to the slag before pressurized steam aging, the Fuller index q was determined in the same manner as in Example 1. Moreover, after performing pressurized steam aging with respect to slag, while performing the particle size distribution measurement and the calculation of Fuller index | exponent q by the method similar to Example 1, the dry density and water immersion expansion coefficient of the test body were measured.
For comparison, the Fuller index q was determined for the slag D plain by the same method as in Example 1. Furthermore, pressurized steam aging was performed with the slag D alone, and the particle size distribution measurement after the aging treatment and the calculation of the Fuller index q were similarly performed, and the dry density and the water immersion expansion rate were measured.
それらの結果を表５及び表６に示す。これによれば、細粒分がやや少ない有姿粒度のスラグＤ（粒度０−４０ｍｍ）はFuller指数ｑが０．６より大きい。これに対して、有姿粒度のスラグＤに細粒のスラグＥ（粒度０−５ｍｍ）を８５：１５（質量比）で混合した発明例５は、Fuller指数ｑが０．４〜０．６の範囲内にある。加圧蒸気エージング後の粒度分布でも、スラグＤはFuller指数ｑが０．６より大きいが、発明例５はFuller指数ｑが０．４〜０．６の範囲内にある。また、発明例５は、スラグＤに較べて乾燥密度が高く、水浸膨張率は０．７％を下回っている。 The results are shown in Tables 5 and 6. According to this, the fuller index q is larger than 0.6 for the slug D (grain size 0-40 mm) having a solid particle size with a little fine particle content. On the other hand, Invention Example 5 in which fine slag E (particle size 0-5 mm) is mixed at 85:15 (mass ratio) with solid slag D has a Fuller index q of 0.4 to 0.6. It is in the range. Even in the particle size distribution after pressurized steam aging, the slag D has a Fuller index q greater than 0.6, but Inventive Example 5 has a Fuller index q in the range of 0.4 to 0.6. In addition, Invention Example 5 has a higher dry density than the slag D, and the water immersion expansion rate is less than 0.7%.
Claims (7)
（ｉ）製鋼スラグ（ａ）の一部について篩目が１０ｍｍ以下の篩（ｘ）で分級することで細粒・微粉分を減じた後、製鋼スラグ（ａ）の残部と混合する。
（ii）以前に、粒径４０ｍｍ以下の割合が８０mass％以上となる粒度に破砕された製鋼スラグを篩目が１０ｍｍ以下の篩（ｘ）で分級することで得られている細粒・微粉分を、製鋼スラグ（ａ）に加えて混合する。 For steelmaking slag (a) crushed to a particle size with a particle size of 40 mm or less at 80 mass% or more, steelmaking slag (a) is increased or decreased under the following conditions (i) or (ii). When the particle size distribution of the steelmaking slag (a) is adjusted so that the Fuller index becomes 0.4 to 0.6 when the particle size distribution of) is approximated by Andreazen's curve formula, pressurized steam aging is performed. A method for producing a steelmaking slag roadbed material.
(I) A part of the steelmaking slag (a) is classified with a sieve (x) having a sieve mesh of 10 mm or less to reduce fine particles and fine powder, and then mixed with the remainder of the steelmaking slag (a).
(Ii) Fine particles and fine powder obtained by classifying steelmaking slag previously crushed to a particle size with a particle size of 40 mm or less being 80 mass% or more with a sieve (x) having a sieve mesh of 10 mm or less Is added to the steelmaking slag (a) and mixed.
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