JP2014169199A - Processing method of steelmaking slag - Google Patents
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Abstract
Description
本発明は、製鋼スラグの処理方法に関する。 The present invention relates to a method for processing steelmaking slag.
製鉄所において、転炉、溶銑予備処理炉等の精錬工程から発生する製鋼スラグは、酸化鉄、Ｃａ２ＳｉＯ４、ＣａＳｉＯ３、ＣａＯ、ＭｇＯ、ＳｉＯ２、Ｐ２Ｏ５などを多く含んでおり、改質処理なしに路盤材、建造物の基礎材などの陸域に適用すると、製鋼スラグ中に不可避的に含まれるＣａ２ＳｉＯ４やＣａＳｉＯ３、ＣａＯが雨水と反応して、流出水のｐＨが上昇し、また、水酸化反応に伴って体積が５〜８％程度も膨張し、さらに、炭酸化によって白濁を引き起こしやすい。 In steelworks, steelmaking slag generated from refining processes such as converters and hot metal pretreatment furnaces contains a large amount of iron oxide, Ca 2 SiO 4 , CaSiO 3 , CaO, MgO, SiO 2 , P 2 O 5 and the like. When applied to land areas such as roadbed materials and building foundation materials without modification treatment, Ca 2 SiO 4 , CaSiO 3 , and CaO inevitably contained in steelmaking slag react with rainwater, and runoff water The pH rises, and the volume expands by about 5 to 8% with the hydroxylation reaction. Further, it tends to cause white turbidity due to carbonation.
これらの現象は下記の反応（１）〜（３）や溶解平衡によって起きている。
１）ｐＨ上昇と膨張：
ＣａＯ ＋ Ｈ２Ｏ → Ｃａ（ＯＨ）２ …（１）
Ｃａ（ＯＨ）２ → Ｃａ２＋ ＋ ２ＯＨ−（平衡ｐＨ＞１２） …（２）
２）その他のｐＨ上昇：
Ｃａ２ＳｉＯ４の溶解平衡ｐＨ＝１１．５、ＣａＳｉＯ３の溶解平衡ｐＨ＝１０．４
３）炭酸化による白濁：
ＣａＯ ＋ＣＯ２→ ＣａＣＯ３↓（ＣａＣＯ３の溶解平衡ｐＨ＝１０．５） …（３）
These phenomena are caused by the following reactions (1) to (3) and dissolution equilibrium.
1) pH increase and swelling:
CaO + H 2 O → Ca (OH) 2 (1)
Ca (OH) 2 → Ca 2+ + 2OH − (equilibrium pH> 12) (2)
2) Other pH increases:
Dissolution equilibrium pH of Ca 2 SiO 4 = 11.5, dissolution equilibrium pH of CaSiO 3 = 10.4
3) Cloudiness due to carbonation:
CaO + CO 2 → CaCO 3 ↓ (CaCO 3 dissolution equilibrium pH = 10.5) (3)
すなわち、製鋼スラグに雨水などがかかると、ＣａＯ単独では水と反応してＣａ（ＯＨ）２を生成する。このＣａ（ＯＨ）２は電離して、水中のＯＨ−イオン濃度を増大させ、ｐＨ＞１２に上昇する原因となる。また、空気中の炭酸ガスや酸性の雨水に溶解した炭酸によって炭酸化が進行し、不溶性のＣａＣＯ３が生成し、白濁の主な原因となる。 That is, when rainwater or the like is applied to the steelmaking slag, CaO alone reacts with water to generate Ca (OH) 2 . This Ca (OH) 2 is ionized, increasing the OH − ion concentration in the water and causing it to rise to pH> 12. In addition, carbonation proceeds by carbon dioxide dissolved in the air or acidic rainwater, and insoluble CaCO 3 is generated, which is a major cause of cloudiness.
そこで、現在では、製鋼スラグの水酸化反応に伴う膨張現象を抑制するために、製鋼スラグを自然冷却し、破砕した後、屋外で山積みするか、或いは人為的に水蒸気と接触させることにより、上記式（１）に示す反応を生じさせ、遊離ＣａＯを安定化させている。
しかし、このエージングは、非常に長時間を要することであり、そのために製鉄所内に非常に広いスペースが必要であるという問題がある。また、人為的に蒸気エージング処理を行う場合には、処理コストが生じる。
Therefore, at present, in order to suppress the expansion phenomenon associated with the hydroxylation reaction of the steelmaking slag, the steelmaking slag is naturally cooled, crushed, and then piled outdoors or artificially brought into contact with water vapor. The reaction shown in Formula (1) is caused to stabilize the free CaO.
However, this aging requires a very long time, and there is a problem that a very large space is required in the steelworks. In addition, when the steam aging process is performed artificially, a processing cost is generated.
このような取扱いが難しい製鋼スラグの処理技術として、平均粒径が１〜２５ｍｍの粒状の製鋼スラグを、硫酸溶液中に保持させることにより、製鋼スラグ粒子表層に硫酸カルシウム層を形成させる改質製鋼スラグの製造方法が知られている（特許文献１参照）。特許文献１の改質製鋼スラグは、製鋼スラグ粒子の表面に硫酸カルシウム層が形成されており、海水に浸漬したときにｐＨ上昇や白濁、固結に対して優れた抵抗力を呈するので、海域の覆砂材や埋め戻し材などの海洋環境修復材として海水に浸漬して使用できると記載されている。 As a steelmaking slag treatment technology that is difficult to handle, a modified steelmaking that forms a calcium sulfate layer on the steelmaking slag particle surface layer by holding granular steelmaking slag having an average particle size of 1 to 25 mm in a sulfuric acid solution. A method for producing slag is known (see Patent Document 1). The modified steelmaking slag of Patent Document 1 has a calcium sulfate layer formed on the surface of steelmaking slag particles, and exhibits excellent resistance to pH rise, cloudiness, and consolidation when immersed in seawater. It is described that it can be used by immersing it in seawater as a marine environmental restoration material such as sand cover material and backfill material.
また、鋼滓を酸で溶解し、ＰＨを調整することにより、鉄、珪酸及びカルシウム分を沈殿させ、分離回収する鋼滓の処理方法が知られている（特許文献２参照）。特許文献２の処理方法では、回収したＣａＳＯ４及びＳｉＯ２はセメント原料、骨材等に利用できることが記載されている。 Moreover, the processing method of the steel plate which precipitates iron, a silicic acid, and a calcium content by melt | dissolving a steel plate with an acid and adjusts PH and isolate | separates it is known (refer patent document 2). In the processing method of Patent Document 2, it is described that the recovered CaSO 4 and SiO 2 can be used for cement raw materials, aggregates, and the like.
一方で、高炉原料の焼結での脱Ｓ剤や製鋼工程の脱Ｐ剤として利用されるＣａＯは、以下の式（４）に示すように、国内の全使用量が石灰石（ＣａＣＯ３）の脱炭酸化で生産されており、そのＣＯ２排出が問題になっている。
ＣａＣＯ３ → ＣａＯ ＋ ＣＯ２ …（４）
On the other hand, as shown in the following formula (4), CaO used as a de-S agent in sintering of blast furnace raw materials and a de-P agent in the steel making process is composed of limestone (CaCO 3 ). It is produced by decarboxylation, and its CO 2 emission is a problem.
CaCO 3 → CaO + CO 2 (4)
本発明の目的は、製鋼スラグから効率よく石膏成分を得ることができるとともに、この石膏成分を焼結副原料として利用することができる、製鋼スラグの処理方法を提供することにある。 The objective of this invention is providing the processing method of the steelmaking slag which can obtain a gypsum component efficiently from steelmaking slag, and can utilize this gypsum component as a sintering auxiliary material.
本発明は、この知見に基づいて上記の課題を解決するためになされたものであり、その要旨とするところは、以下のとおりである。 The present invention has been made to solve the above-mentioned problems based on this finding, and the gist thereof is as follows.
（１）製鋼スラグを粒径５００μｍ未満に分級する工程と、前記分級して得られた製鋼スラグ粉末を溶解槽において硫酸溶液で処理することによりＣａ分は不溶性のＣａＳＯ４に分離し、少なくともＡｌ、Ｃｒ、Ｍｎ、Ｐ及びＦｅ分は溶解液に分離する工程と、前記処理した溶液を固液分離してＣａＳＯ４を回収する工程と、前記回収したＣａＳＯ４を焼結副原料として利用する工程と、を実施することを特徴とする製鋼スラグの処理方法。 (1) A step of classifying steelmaking slag to a particle size of less than 500 μm, and treating the steelmaking slag powder obtained by the classification with a sulfuric acid solution in a dissolution tank, thereby separating Ca content into insoluble CaSO 4 , and at least Al , Cr, Mn, P and Fe components are separated into a solution, a step of recovering CaSO 4 by solid-liquid separation of the treated solution, and a step of using the recovered CaSO 4 as a sintering auxiliary material. And a method for treating steelmaking slag, characterized in that:
（２）上述の（１）に記載の製鋼スラグの処理方法であって、前記分級する製鋼スラグ粉末が粒径２５０μｍ以下であることを特徴とする製鋼スラグの処理方法。 (2) The steelmaking slag treatment method according to (1) above, wherein the steelmaking slag powder to be classified has a particle size of 250 μm or less.
（３）上述の（１）または（２）に記載の製鋼スラグの処理方法であって、前記製鋼スラグ粉末の硫酸溶液による処理は、ｐＨが−２以上＋０．８以下の範囲で行われることを特徴とする製鋼スラグの処理方法。 (3) The steelmaking slag treatment method according to (1) or (2) above, wherein the steelmaking slag powder is treated with a sulfuric acid solution in a pH range of −2 to +0.8. A method for treating steelmaking slag characterized by the above.
（４）上述の（１）から（３）のいずれかに記載の製鋼スラグの処理方法であって、前記硫酸溶液に使用される硫酸がコークス炉から排出されたＳ成分から製造された硫酸であることを特徴とする製鋼スラグの処理方法。 (4) The steelmaking slag treatment method according to any one of (1) to (3) above, wherein the sulfuric acid used in the sulfuric acid solution is sulfuric acid produced from the S component discharged from the coke oven. A method for treating steelmaking slag, comprising:
本発明の製鋼スラグの処理方法は、製鋼スラグから効率よく石膏成分を得ることができるとともに、この石膏成分を焼結副原料として利用することができる。 The steelmaking slag treatment method of the present invention can efficiently obtain a gypsum component from the steelmaking slag, and can utilize this gypsum component as a sintering auxiliary material.
以下、本発明の実施形態を詳細に説明する。
本実施形態の製鋼スラグの処理方法では、製鋼スラグを粒径５００μｍ未満に分級する工程と、分級して得られた製鋼スラグ粉末を溶解槽において硫酸溶液で処理することによりＣａ分は不溶性のＣａＳＯ４に分離し、少なくともＡｌ、Ｃｒ、Ｍｎ、Ｐ及びＦｅ分は溶解液に分離する工程と、処理した溶液を固液分離してＣａＳＯ４を回収する工程と、回収したＣａＳＯ４を焼結副原料として利用する工程と、を実施する。
Hereinafter, embodiments of the present invention will be described in detail.
In the steelmaking slag treatment method of the present embodiment, the step of classifying the steelmaking slag to a particle size of less than 500 μm, and treating the steelmaking slag powder obtained by classification with a sulfuric acid solution in a dissolution tank, Ca is insoluble in CaSO. separated into 4, at least Al, Cr, Mn, and separating the P and Fe content is solution, and recovering the CaSO 4 treated solution to solid-liquid separation to, recovered the CaSO 4 sintered sub And a step of using it as a raw material.
＜製鋼スラグの分級＞
先ず、製鋼スラグを粒径５００μｍ未満に分級する。分級して得られる製鋼スラグ粉末の粒径が５００μｍ以上であると、後述する硫酸溶液処理をしても、製鋼スラグ粉末の表層部分のみが石膏化されるに留まり、製鋼スラグ粉末の内部は十分に石膏化されない不具合を生じる。このうち、分級して得られる製鋼スラグ粉末は、後述する硫酸溶液処理をして、製鋼スラグ粉末の表層部分だけでなく、製鋼スラグ粉末の内部も十分に石膏化される大きさである、粒径２５０μｍ以下がより好ましく、粒径１２５μｍ以下が特に好ましい。
<Classification of steelmaking slag>
First, steelmaking slag is classified to a particle size of less than 500 μm. When the particle size of the steelmaking slag powder obtained by classification is 500 μm or more, only the surface layer portion of the steelmaking slag powder is plastered even after the sulfuric acid solution treatment described later, and the inside of the steelmaking slag powder is sufficient. This causes a defect that is not plastered. Among these, the steelmaking slag powder obtained by classification is treated with a sulfuric acid solution, which will be described later, and the size is such that not only the surface layer portion of the steelmaking slag powder but also the inside of the steelmaking slag powder is sufficiently plastered, A diameter of 250 μm or less is more preferable, and a particle diameter of 125 μm or less is particularly preferable.
製鋼スラグの分級は、所定の目開きを有するステンレス網などによる篩がけなど、分級可能な手法であれば、特に問わない。工業的グレードで行う際の分級手法としては、所定の目開きを有するスクリーンマット上に製鋼スラグを載せ、スクリーンマットを波動運動させることによってスクリーンマット上の製鋼スラグを高く跳ね上げ反転、解砕、及び分散させることで、所定の粒径に篩分けすることが好ましい。上記分級手法としては、ユーラステクノ社製のジャンピングスクリーン装置を使用することが好ましい。 The classification of steelmaking slag is not particularly limited as long as it can be classified, such as sieving with a stainless steel mesh having a predetermined opening. As a classification method when performing at an industrial grade, steelmaking slag is placed on a screen mat having a predetermined opening, and the screen mat is waved to cause the steelmaking slag on the screen mat to be flipped up and reversed, crushed, And, it is preferable to sieve to a predetermined particle size by dispersing. As the classification method, it is preferable to use a jumping screen device manufactured by Eurus Techno.
＜製鋼スラグ粉末の硫酸溶液処理＞
次いで、分級して得られた製鋼スラグ粉末を溶解槽において硫酸溶液で処理する。製鋼スラグ粉末には遊離ＣａＯやＣａ分を含むＣａＳｉＯ３、Ｃａ２ＳｉＯ４、Ｃａ３ＳｉＯ５、Ｃａ２Ａｌ２Ｏ５等の複合酸化物が含まれるが、この硫酸溶液処理によって製鋼スラグ粉末中のＣａ分は、石膏化され、不溶性であり、乾燥時に固化する特徴を有するＣａＳＯ４として分離される。また、この硫酸溶液処理によって、製鋼スラグ粉末中の、少なくともＡｌ、Ｃｒ、Ｍｎ、Ｐ及びＦｅ分は溶解液に分離される。
この硫酸溶液処理では、所定量の硫酸溶液が貯留された溶解槽中に、製鋼スラグ粉末を投入する際に、製鋼スラグ粉末と硫酸溶液との混合比、即ち、固液比（質量比）が１：２〜１：２０の範囲内になるように、製鋼スラグ粉末投入量を調整することが好ましい。固液比が上記範囲内であれば、投入した製鋼スラグ粉末の石膏化がスムーズに行われる。一方、上記固液比が１：２よりも製鋼スラグ粉末の投入量が多いと、製鋼スラグ粉末の石膏化が十分に行われないおそれがある。他方、固液比が１：２０よりも製鋼スラグ粉末の投入量が少なくても、その処理効果は変わらないため、処理コストが向上するおそれがある。このうち、硫酸溶液と製鋼スラグ粉末との固液比は、１：５〜１：１５の範囲内がより好ましい。
<Sulfuric acid solution treatment of steelmaking slag powder>
Next, the steelmaking slag powder obtained by classification is treated with a sulfuric acid solution in a dissolution tank. Steelmaking slag powder contains complex oxides such as CaSiO 3 , Ca 2 SiO 4 , Ca 3 SiO 5 , Ca 2 Al 2 O 5 containing free CaO and Ca content. The Ca content of the gypsum is gypsumized, insoluble, and separated as CaSO 4 with the characteristic of solidifying upon drying. In addition, by this sulfuric acid solution treatment, at least Al, Cr, Mn, P and Fe components in the steelmaking slag powder are separated into a solution.
In this sulfuric acid solution treatment, when steelmaking slag powder is introduced into a dissolution tank in which a predetermined amount of sulfuric acid solution is stored, the mixing ratio of the steelmaking slag powder and the sulfuric acid solution, that is, the solid-liquid ratio (mass ratio) is It is preferable to adjust the amount of steelmaking slag powder input so that it falls within the range of 1: 2 to 1:20. If the solid-liquid ratio is within the above range, the cast steelmaking slag powder is smoothly plastered. On the other hand, when the amount of the steelmaking slag powder is larger than 1: 2, the gypsumization of the steelmaking slag powder may not be performed sufficiently. On the other hand, even if the input amount of steelmaking slag powder is less than 1:20, the processing effect does not change, so that the processing cost may be improved. Among these, the solid-liquid ratio between the sulfuric acid solution and the steelmaking slag powder is more preferably in the range of 1: 5 to 1:15.
硫酸溶液処理で使用される硫酸溶液は、硫酸濃度が１０〜２５％であることが好ましい。一方、硫酸濃度が１０％未満では、製鋼スラグ粉末の石膏化が十分に行われないおそれがある。他方、硫酸濃度が２５％を超えると、Ｃａ以外の硫酸溶液への溶解量が急激に増加することにより、石膏の回収率が低下するおそれがある。
硫酸溶液に使用される硫酸は、コークス炉から排出されたＳ成分から製造された硫酸であることが好ましい。従来、コークス炉から余剰に排出されているＳ成分から製造された硫酸は、ＮａＯＨで中和した後に、海洋投棄処分していたが、この硫酸溶液処理において、コークス炉から排出されたＳ成分から製造された硫酸を使用することで、コークス炉起因の余剰硫酸の廃棄コストを低減するという更なる効果を奏することができる。
The sulfuric acid solution used in the sulfuric acid solution treatment preferably has a sulfuric acid concentration of 10 to 25%. On the other hand, if the sulfuric acid concentration is less than 10%, the steelmaking slag powder may not be sufficiently plastered. On the other hand, when the sulfuric acid concentration exceeds 25%, the amount of gypsum recovered in the sulfuric acid solution other than Ca may be rapidly increased, thereby reducing the recovery rate of gypsum.
The sulfuric acid used in the sulfuric acid solution is preferably sulfuric acid produced from the S component discharged from the coke oven. Conventionally, sulfuric acid produced from an excessively discharged S component from a coke oven was disposed of in the ocean after neutralization with NaOH, but in this sulfuric acid solution treatment, the sulfuric acid was discharged from the S component discharged from the coke oven. By using the produced sulfuric acid, a further effect of reducing the disposal cost of surplus sulfuric acid caused by the coke oven can be achieved.
製鋼スラグ粉末の硫酸溶液による処理は、ｐＨが−２以上＋０．８以下の範囲で行われることが好ましい。溶解槽中のｐＨが上記範囲内となるように硫酸溶液処理を行うことで、製鋼スラグ粉末中のＣａ成分を石膏化させるだけでなく、ＦｅやＰ２Ｏ５等の有価物を溶解液中に移行させることができるので、ＦｅやＰ２Ｏ５等の有価物を選択的に分離できる。
製鋼スラグ粉末の硫酸溶液処理は、均一な反応を生じさせるために、製鋼スラグ粉末を投入した溶解槽中を撹拌しながら反応させることが好ましい。
製鋼スラグ粉末の硫酸溶液処理時間は、１０分以上２時間以下が好ましい。より好ましくは２０分以上３０分以下である。処理時間が１０分未満では溶解槽中に投入した製鋼スラグ粉末の全量を十分に石膏化させることができないおそれがあり、また、２時間を超えてもその処理効果は変わらないため、処理コストが増加するおそれがある。
The treatment of the steelmaking slag powder with the sulfuric acid solution is preferably performed in the range of pH of −2 to +0.8. By carrying out the sulfuric acid solution treatment so that the pH in the dissolution tank falls within the above range, not only gypsum the Ca component in the steelmaking slag powder but also valuable materials such as Fe and P 2 O 5 in the solution. Therefore, valuable materials such as Fe and P 2 O 5 can be selectively separated.
In the sulfuric acid solution treatment of the steelmaking slag powder, in order to cause a uniform reaction, it is preferable to cause the reaction in the dissolution tank into which the steelmaking slag powder is charged while stirring.
The sulfuric acid solution treatment time for steelmaking slag powder is preferably 10 minutes or more and 2 hours or less. More preferably, it is 20 minutes or more and 30 minutes or less. If the treatment time is less than 10 minutes, the entire amount of steelmaking slag powder charged into the dissolution tank may not be sufficiently plastered, and the treatment effect does not change even if the treatment time exceeds 2 hours. May increase.
＜固液分離＞
次に、上記処理した溶液を固液分離してＣａＳＯ４を回収する。
固液分離としては、濾過、遠心分離、加圧脱水（ローラープレス、フィルタープレス、スクリュープレス）、多重円板回転脱水、多重板波動フィルターなどによる手法や、化学的作用を利用した凝集剤を用いる方法などが挙げられる。
固液分離後に回収したＣａＳＯ４は、必要に応じて洗浄水により洗浄することが好ましい。洗浄水による洗浄によって、固液分離後の固形分中に含まれる硫酸成分やＦｅ、Ｍｇ、Ｍｎなどを洗浄水中に移行させることで、固形分中の不純物量を低減することができる。洗浄水による洗浄は、洗浄水を多段階で使用することが好ましく、例えば、一度洗浄に使用した洗浄廃水を循環させて再度洗浄水として利用することによって洗浄処理を高効率化できる。
<Solid-liquid separation>
Next, the treated solution is subjected to solid-liquid separation to recover CaSO 4 .
For solid-liquid separation, methods such as filtration, centrifugation, pressure dehydration (roller press, filter press, screw press), multiple disk rotary dehydration, multiple plate wave filter, and flocculant using chemical action are used. The method etc. are mentioned.
CaSO 4 recovered after the solid-liquid separation is preferably washed with washing water as necessary. By transferring the sulfuric acid component, Fe, Mg, Mn and the like contained in the solid content after solid-liquid separation into the wash water by washing with the wash water, the amount of impurities in the solid content can be reduced. Washing with washing water is preferably performed in multiple stages. For example, washing wastewater once used for washing can be circulated and reused as washing water to increase the efficiency of the washing treatment.
固液分離後に回収したＣａＳＯ４、或いは洗浄後のＣａＳＯ４は、乾燥処理することが好ましい。乾燥処理は、特に手法は問わないが、例えば、室温環境下において放置することによる自然乾燥でよい。室温環境下であれば、例えば、１２時間程度放置しておけば、十分に乾燥される。
乾燥処理後のＣａＳＯ４は、必要に応じて、解砕し、後述の用途に供される。解砕の手法は特に問わず、後述の用途に適した大きさになるように解砕すればよい。
このように、上記処理をすることで製鋼スラグから効率よく石膏成分を得ることができる。
The CaSO 4 recovered after the solid-liquid separation or the washed CaSO 4 is preferably subjected to a drying treatment. The drying process is not particularly limited, and may be natural drying by leaving it in a room temperature environment, for example. In a room temperature environment, for example, if it is left for about 12 hours, it will be sufficiently dried.
The CaSO 4 after the drying treatment is crushed as necessary and provided for the use described later. The crushing method is not particularly limited, and may be crushed so as to have a size suitable for the use described later.
Thus, a gypsum component can be efficiently obtained from steelmaking slag by performing the said process.
また、固液分離により固形分が除かれた硫酸溶液には、少なくともＡｌ、Ｃｒ、Ｍｎ、Ｐ及びＦｅ分が含まれている。また、ＳｉやＭｇ、Ｔｉ分なども含まれている。
この固液分離後の硫酸溶液は、中和処理され、Ｃｒ、Ｐなどが基準内であることを確認した後、海洋投棄してもよい。
In addition, the sulfuric acid solution from which the solid content has been removed by solid-liquid separation contains at least Al, Cr, Mn, P and Fe. Also included are Si, Mg, Ti and the like.
The sulfuric acid solution after the solid-liquid separation is neutralized, and after confirming that Cr, P, etc. are within the standard, it may be discarded to the ocean.
＜ＣａＳＯ４の利用＞
そして、上記回収したＣａＳＯ４を焼結副原料として利用する。上記回収したＣａＳＯ４には、Ｆｅ２Ｏ３やＳｉＯ２が含まれているため、従来から、焼結の副材料として使用されている、塩基度調整用の石灰石の一部代替えが可能となる。
なお、ＣａＳＯ４にはＳ分が含まれているが、ＣａＳＯ４を焼結副原料として使用しても、焼結で一般的に使用される脱硫装置によって、このＳ分は十分に脱硫処理することが可能である。
<Use of CaSO 4 >
The recovered CaSO 4 is used as a sintering auxiliary material. Since the recovered CaSO 4 contains Fe 2 O 3 and SiO 2 , it is possible to partially replace limestone for adjusting the basicity, which has been conventionally used as a secondary material for sintering. .
Note that the CaSO 4 is contains S content, the use of CaSO 4 as the sintering auxiliary materials, the desulfurization equipment commonly used in sintering, the S content is thoroughly desulfurized It is possible.
次に実施例により本発明をさらに詳しく説明するが、本発明はこれらの例によって何ら制限されるものではない。 EXAMPLES Next, although an Example demonstrates this invention in more detail, this invention is not restrict | limited at all by these examples.
〔実施例１〕
先ず、粒径０〜２ｍｍの製鋼スラグを用意し、この製鋼スラグを所定の目開きを有するステンレス製の網による篩がけをして、所定の粒径の製鋼スラグ粉末に分級した。分級した製鋼スラグ粉末は、粒径１２５μｍ未満、粒径２５０μｍ未満、及び、粒径５００μｍ未満である。また、未分級の粒径０〜２ｍｍの製鋼スラグも比較として用意した。次の表１に製鋼スラグ粉末の成分組成を示す。
[Example 1]
First, a steelmaking slag having a particle diameter of 0 to 2 mm was prepared, and the steelmaking slag was sieved with a stainless steel net having a predetermined opening, and classified into a steelmaking slag powder having a predetermined particle diameter. The classified steelmaking slag powder has a particle size of less than 125 μm, a particle size of less than 250 μm, and a particle size of less than 500 μm. An unclassified steelmaking slag having a particle size of 0 to 2 mm was also prepared for comparison. Table 1 below shows the composition of steelmaking slag powder.
また、２０％濃度の硫酸溶液を用意した。
次に、硫酸溶液５０ｇを溶解槽に貯留し、製鋼スラグ粉末と硫酸溶液との固液比が１：５になるように、上記分級して得られた製鋼スラグ粉末１０ｇを投入した。製鋼スラグ粉末投入後は、溶解槽中の液温を６５℃とし、撹拌しながら２時間保持した。溶解槽中のｐＨは、０．５であった。
次に、硫酸溶液処理を終えた溶液を濾過し、固形分と溶解液とに分離した。
分離回収後の固形物を乾燥させ、固形物に対して蛍光Ｘ線による成分分析を行い、固形物中のＣａＳＯ４成分の回収量を求めた。その結果を次の表２に示す。
A 20% strength sulfuric acid solution was also prepared.
Next, 50 g of the sulfuric acid solution was stored in the dissolution tank, and 10 g of the steelmaking slag powder obtained by the above classification was added so that the solid-liquid ratio of the steelmaking slag powder and the sulfuric acid solution was 1: 5. After the steelmaking slag powder was charged, the liquid temperature in the dissolution tank was set to 65 ° C. and held for 2 hours while stirring. The pH in the dissolution tank was 0.5.
Next, the solution after the sulfuric acid solution treatment was filtered to separate it into a solid content and a solution.
The solid material after separation and recovery was dried, and component analysis was performed on the solid material by fluorescent X-rays, and the recovered amount of CaSO 4 component in the solid material was determined. The results are shown in Table 2 below.
表２から明らかなように、各粒径にそれぞれ分級した製鋼スラグ粉末は、ＣａＳＯ４の回収量が高い結果が得られた。一方で、未分級の製鋼スラグ粉末は、粒径の大きな粒子が含まれていることもあり、ＣａＳＯ４の回収量が低い結果となった。
また、分級による粒径が細かいほどＣａＳＯ４の回収量が高い結果となった。この結果から、分級して得られた製鋼スラグ粉末の粒径が５００μｍ未満であれば、ＣａＳＯ４の回収量が大きいことが確認された。また、回収量が大きい、粒径２５０μｍ未満が好ましく、粒径１２５μｍ未満が特に好ましいことが確認された。
As is apparent from Table 2, the steelmaking slag powder classified into each particle size obtained a high recovery amount of CaSO 4 . On the other hand, unclassified steelmaking slag powder may contain particles having a large particle size, resulting in a low recovery amount of CaSO 4 .
Further, the smaller the particle size obtained by classification, the higher the amount of CaSO 4 recovered. From this result, it was confirmed that the recovered amount of CaSO 4 was large when the particle size of the steelmaking slag powder obtained by classification was less than 500 μm. Further, it was confirmed that the recovery amount is large, the particle size is preferably less than 250 μm, and the particle size is preferably less than 125 μm.
〔実施例２〕
先ず、粒径０〜５ｍｍの製鋼スラグを用意し、この製鋼スラグをステンレス製の網による篩がけをして、粒径１２５μｍ未満の製鋼スラグ粉末に分級した。
また、２０％濃度の硫酸溶液を用意した。
次に、硫酸溶液５０ｇを溶解槽に貯留し、製鋼スラグ粉末と硫酸溶液との固液比が１：５になるように、上記分級して得られた製鋼スラグ粉末１０ｇを投入した。製鋼スラグ粉末投入後は、溶解槽中の液温を６５℃とし、撹拌しながら２時間保持した。溶解槽中のｐＨは、０．５であった。
次に、硫酸溶液処理を終えた溶液を濾過し、固形分と溶解液とに分離した。
分離した溶解液を乾固し、乾固物に対して蛍光Ｘ線による成分分析を行い、溶解液中に溶解している各成分量（酸化物換算）を求めた。その結果を次の表３に示す。
[Example 2]
First, a steelmaking slag having a particle size of 0 to 5 mm was prepared, and the steelmaking slag was sieved with a stainless steel net and classified into a steelmaking slag powder having a particle size of less than 125 μm.
A 20% strength sulfuric acid solution was also prepared.
Next, 50 g of the sulfuric acid solution was stored in the dissolution tank, and 10 g of the steelmaking slag powder obtained by the above classification was added so that the solid-liquid ratio of the steelmaking slag powder and the sulfuric acid solution was 1: 5. After the steelmaking slag powder was charged, the liquid temperature in the dissolution tank was set to 65 ° C. and held for 2 hours while stirring. The pH in the dissolution tank was 0.5.
Next, the solution after the sulfuric acid solution treatment was filtered to separate it into a solid content and a solution.
The separated dissolved solution was dried, and component analysis was performed on the dried product by fluorescent X-rays to determine the amount of each component dissolved in the dissolved solution (as oxide). The results are shown in Table 3 below.
表３から明らかなように、乾固物はＦｅ２Ｏ３が主成分であり、ＡｌやＣｒ、Ｍｎ、Ｐなどが溶解液中に移行していることが確認された。また、ＳｉやＭｇ、Ｔｉなども溶解液中に移行していることが確認された。
一方、この乾固物中にはＣａ分がほとんど含まれておらず、硫酸溶液処理によってＣａ成分と、その他の成分とを選択的に分離していることが確認された。
As is apparent from Table 3, it was confirmed that the dried product was mainly composed of Fe 2 O 3 and Al, Cr, Mn, P, etc. were transferred into the solution. Further, it was confirmed that Si, Mg, Ti and the like were also transferred into the solution.
On the other hand, it was confirmed that this dried product contained almost no Ca component, and that the Ca component and other components were selectively separated by the sulfuric acid solution treatment.
〔実施例３〕
硫酸濃度が１０％、２０％、２５％、３０％、４０％、５０％にそれぞれ調整された硫酸溶液を使用した以外は、上記実施例２と同様にして硫酸溶液処理を実施した。
硫酸溶液処理を終えた溶液は濾過し、固形分と溶解液とに分離した。
分離回収後の固形物を乾燥させ、固形物に対して蛍光Ｘ線による成分分析を行い、ＣａＳＯ４の回収量を求めた。その結果を次の表４に示す。
Example 3
The sulfuric acid solution treatment was performed in the same manner as in Example 2 above, except that sulfuric acid solutions adjusted to 10%, 20%, 25%, 30%, 40%, and 50% respectively were used.
The solution that had been treated with the sulfuric acid solution was filtered and separated into a solid content and a solution.
The solid after the separation and recovery was dried, and component analysis was performed on the solid by X-ray fluorescence to determine the amount of CaSO 4 recovered. The results are shown in Table 4 below.
表４から明らかなように、硫酸溶液の硫酸濃度が高すぎると、回収率が徐々に低下する傾向がみられた。この結果から、硫酸溶液処理では、回収率が高くなる、２０％濃度以下の硫酸溶液を使用することが好ましいことが確認された。なお、表４では、理論ＣａＳＯ４回収量を上回る量が回収されている例が示されている。このような回収量となった１つ目の理由としては、蛍光Ｘ線の定量性が低かったことで誤差を生じたものと推察される。２つ目の理由としては、ＣａＳＯ４は、空気中の水分でも比較的短時間でＣａＳＯ４・１／２Ｈ２ＯやＣａＳＯ４・２Ｈ２Ｏに変化するため、成分分析時のＣａＯ＋ＳＯ３の合計が、理論ＣａＳＯ４（無水）よりも上回ったものと推察される。
また、２５％〜５０％濃度の硫酸溶液処理結果では、２０％濃度硫酸溶液処理結果に比べて、ＣａＳＯ４回収率が大幅に低下している結果になっているが、これは硫酸中にＣａイオンの溶解量が増えること以外にも、析出するＣａＳＯ４に一部付着するＦｅ、Ｍｇ、Ｍｎ、Ａｌ、Ｓｉなどの溶解量が増えることで見掛け回収量が低下しているためである。
As is apparent from Table 4, when the sulfuric acid concentration of the sulfuric acid solution was too high, the recovery rate gradually decreased. From this result, it was confirmed that in the sulfuric acid solution treatment, it is preferable to use a sulfuric acid solution having a concentration of 20% or less, which increases the recovery rate. Table 4 shows an example in which an amount exceeding the theoretical CaSO 4 recovery amount is recovered. As a first reason for such a recovery amount, it is presumed that an error has occurred due to low quantitativeness of fluorescent X-rays. The second reason is that CaSO 4 changes to CaSO 4 · 1 / 2H 2 O or CaSO 4 · 2H 2 O in a relatively short time even with moisture in the air, so the total of CaO + SO 3 at the time of component analysis However, it is surmised that it exceeded the theoretical CaSO 4 (anhydrous).
In addition, the result of treatment with a sulfuric acid solution having a concentration of 25% to 50% is a result in which the CaSO 4 recovery rate is greatly reduced compared with the result of treatment with a sulfuric acid solution of 20% concentration. This is because, in addition to the increase in the dissolved amount of ions, the apparent recovery amount is reduced due to the increase in the dissolved amount of Fe, Mg, Mn, Al, Si, etc. partially adhering to the precipitated CaSO 4 .
〔実施例４〕
処理量を工業的グレードに変更した以外は、実施例１と同様にして、硫酸溶液処理を実施した。硫酸溶液処理を終えた溶液は濾過し、固形分と溶解液とに分離した。分離回収後の固形物は洗浄水により洗浄した後、乾燥処理し、解砕することでＣａＳＯ４粉を回収した。
次に、焼結の副原料である石灰石の一部に代えて、回収したＣａＳＯ４を焼結副原料として、例えば、塩基度調整用に用いられるＣａＣＯ３の一部もしくは全量を代替し、利用したところ、造粒性や焼結性は、ＣａＳＯ４粉を使用する前と比べても遜色がないことが確認された。
Example 4
A sulfuric acid solution treatment was performed in the same manner as in Example 1 except that the treatment amount was changed to an industrial grade. The solution that had been treated with the sulfuric acid solution was filtered and separated into a solid content and a solution. The solid after separation and recovery was washed with washing water, dried, and crushed to recover CaSO 4 powder.
Next, instead of a part of the limestone that is a sintering auxiliary material, the recovered CaSO 4 is used as a sintering auxiliary material, for example, replacing a part or all of CaCO 3 used for adjusting the basicity, and using it. As a result, it was confirmed that the granulation property and sinterability were not inferior to those before using the CaSO 4 powder.
Claims (4)
前記分級して得られた製鋼スラグ粉末を溶解槽において硫酸溶液で処理することによりＣａ分は不溶性のＣａＳＯ４に分離し、少なくともＡｌ、Ｃｒ、Ｍｎ、Ｐ及びＦｅ分は溶解液に分離する工程と、
前記処理した溶液を固液分離してＣａＳＯ４を回収する工程と、
前記回収したＣａＳＯ４を焼結副原料として利用する工程と、
を実施することを特徴とする製鋼スラグの処理方法。 Classifying the steelmaking slag to a particle size of less than 500 μm;
The Ca content by treatment with sulfuric acid solution in the dissolution tank and classified steelmaking slag powder obtained is separated into CaSO 4-insoluble, at least Al, Cr, Mn, step P and Fe content is separated into solution When,
Solid-liquid separation of the treated solution to recover CaSO 4 ;
Using the recovered CaSO 4 as a sintering auxiliary material;
A method for treating steelmaking slag, characterized in that
前記分級する製鋼スラグ粉末が粒径２５０μｍ以下である
ことを特徴とする製鋼スラグの処理方法。 It is a processing method of the steelmaking slag of Claim 1, Comprising:
The steelmaking slag powder to be classified has a particle size of 250 μm or less.
前記製鋼スラグ粉末の硫酸溶液による処理は、ｐＨが−２以上＋０．８以下の範囲で行われる
ことを特徴とする製鋼スラグの処理方法。 It is a processing method of the steelmaking slag of Claim 1 or Claim 2, Comprising:
The steelmaking slag powder is treated with a sulfuric acid solution in a pH range of −2 to +0.8.
前記硫酸溶液に使用される硫酸がコークス炉から排出されたＳ成分から製造された硫酸である
ことを特徴とする製鋼スラグの処理方法。
It is a processing method of the steelmaking slag in any one of Claims 1-3,
A method for treating steelmaking slag, wherein the sulfuric acid used in the sulfuric acid solution is sulfuric acid produced from an S component discharged from a coke oven.
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| CN109608062A (en) * | 2018-12-12 | 2019-04-12 | 盐城市国泰混凝土有限公司 | A kind of Silicon-rich magnesium nickel dreg concrete reinforcing agent and nickel slag enhance concrete material |
| WO2019231229A1 (en) * | 2018-05-30 | 2019-12-05 | 주식회사 케이스트 | Method for preparing chemical gypsum having so3 content of 38 % or greater (weight basis) by preparing alkali neutralizer using industrial byproducts containing steel slag or calcium oxide as major raw materials and neutralizing waste acid by dry method |
| KR20210073082A (en) * | 2019-12-10 | 2021-06-18 | 주식회사 포스코 | Neutralized gypsum composition for cement, method for producing the neutralized gypsum for cement, and cement comprising the neutralized gypsum |
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