JP2000086322A - Hexavalent chromium leach reducing agent for hydraulic material, and method for reducing hexavalent chromium leach - Google Patents

Hexavalent chromium leach reducing agent for hydraulic material, and method for reducing hexavalent chromium leach

Info

Publication number
JP2000086322A
JP2000086322A JP26272598A JP26272598A JP2000086322A JP 2000086322 A JP2000086322 A JP 2000086322A JP 26272598 A JP26272598 A JP 26272598A JP 26272598 A JP26272598 A JP 26272598A JP 2000086322 A JP2000086322 A JP 2000086322A
Authority
JP
Japan
Prior art keywords
hexavalent chromium
reducing
acting
hydraulic
substance
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP26272598A
Other languages
Japanese (ja)
Inventor
Masahiko Moriya
政彦 守屋
Kota Sasaki
宏太 佐々木
Koichi Uchida
晃一 内田
Masaaki Noguchi
雅朗 野口
Hidenori Isoda
英典 礒田
Masayuki Hashimoto
真幸 橋本
Chu Hirao
宙 平尾
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Taiheiyo Cement Corp
Original Assignee
Taiheiyo Cement Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Taiheiyo Cement Corp filed Critical Taiheiyo Cement Corp
Priority to JP26272598A priority Critical patent/JP2000086322A/en
Publication of JP2000086322A publication Critical patent/JP2000086322A/en
Pending legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B22/00—Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators, shrinkage compensating agents
    • C04B22/08—Acids or salts thereof
    • C04B22/14—Acids or salts thereof containing sulfur in the anion, e.g. sulfides
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
    • C04B2103/0068—Ingredients with a function or property not provided for elsewhere in C04B2103/00
    • C04B2103/0096—Reducing agents
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00017—Aspects relating to the protection of the environment
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
    • C04B2111/00767—Uses not provided for elsewhere in C04B2111/00 for waste stabilisation purposes
    • 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
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/91—Use of waste materials as fillers for mortars or concrete

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)
  • Soil Conditioners And Soil-Stabilizing Materials (AREA)

Abstract

PROBLEM TO BE SOLVED: To obtain the subject agent for reducing hexavalent chromium leach from hydraulic materials by including materials consisting mainly of hexavalent-reductive substances. SOLUTION: This agent comprises various kinds of reductive substances which are as follows: ferrous sulfate and/or ammonium sulfide and/or the like act as quick- acting reductive substance(s), while blast furnace slag, sulfur, peat, lignite and/or the like as slow-acting reductive substance(s); sodium thiosulfate and/or potassium thiosulfate is effective for insolubilizing hexavalent chromium over short/long period; for the reductive substances, one or more kinds can be combinedly used, however it is preferable to combinedly use quick-acting and slow-acting reductive substances, thereby exhibiting effect both at the initial stage and over a long period; the amounts of reductive substances except blast furnace slag to be used are each 0.1-10 pts.wt. based on 100 pts.wt. of a hydraulic material, being 5-900 pts.wt. based on the blast furnace slag; the reductive substances are used in the form of a hydraulic material through previously mixing into cement; besides, they are used by mixing into a grouting material or soil improving material, or used in producing cement paste, mortar, or concrete.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、水硬性物質の水和
過程で溶出する６価クロムを低減する材料及びこれを含
有する水硬性組成物等に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material for reducing hexavalent chromium eluted during the hydration process of a hydraulic substance, a hydraulic composition containing the same, and the like.

【０００２】[0002]

【従来の技術】近年、環境保全や環境浄化に関する社会
的要請から、各種の産業分野で産業廃棄物等の処理やリ
サイクルが活発に進められており、産業廃棄物、下水汚
泥、生活廃棄物等の廃棄物の処理にあたっては、セメン
ト及びセメントを主成分とする固化材が多用されてい
る。しかし、セメント及びセメント固化材も、その使用
環境によって、水和過程で微量成分が溶出する場合があ
る。事実、ヨーロッパ製のセメントでは、比較的多くの
６価クロムの溶出がみられる。2. Description of the Related Art In recent years, due to social demands for environmental preservation and environmental purification, the treatment and recycling of industrial waste has been actively promoted in various industrial fields, such as industrial waste, sewage sludge, domestic waste, and the like. In the treatment of waste, cement and a solidifying material containing cement as a main component are frequently used. However, also in cement and cement solidifying materials, trace components may be eluted during the hydration process depending on the use environment. In fact, relatively high amounts of hexavalent chromium are eluted in European cement.

【０００３】そこで、水硬性物質からの６価クロムの溶
出を低減する手段が望まれるが、既に、幾つかの方法が
提案されている。例えば、特開平３−２０５３３１号公
報では、第１鉄、第１錫、第１バナジウム、第１銅等の
塩の添加が、また、特開昭４８−８３１１４号公報で
は、水溶性第１鉄塩の添加が提案されている。かかる塩
は６価クロムを３価クロムに還元して不溶化する効果が
ある。しかし、第１鉄以外の該重金属は毒性を有し、６
価クロムを固定できたとしても、新たな重金属の溶出が
問題となる場合がある。また、第１鉄塩は、６価クロム
の初期の溶出防止に有効であるとしても、速やかに空気
酸化されて還元作用が失われるため、長期に渡っての不
溶化効果は期待できない。セメントの水和は長期に渡っ
て進行するため、第１鉄塩による６価クロムの溶出防止
効果は、自ずと時期的に限定されるのである。Therefore, means for reducing the elution of hexavalent chromium from hydraulic substances is desired, but several methods have already been proposed. For example, JP-A-3-205331 discloses the addition of salts such as ferrous, stannous, vanadium, and cuprous salts, and JP-A-48-83114 discloses the addition of water-soluble ferrous iron. Addition of salt has been proposed. Such salts have the effect of reducing hexavalent chromium to trivalent chromium and insolubilizing it. However, the heavy metals other than ferrous are toxic, and 6
Even if chromium (VI) can be fixed, elution of new heavy metals may be a problem. Further, even if ferrous salt is effective in preventing the initial elution of hexavalent chromium, the ferrous salt is rapidly oxidized by air and loses its reducing effect, so that a long-term insolubilizing effect cannot be expected. Since the hydration of cement proceeds over a long period of time, the effect of ferrous salt to prevent elution of hexavalent chromium is naturally limited in time.

【０００４】[0004]

【発明が解決しようとする課題】本発明は係る事情に鑑
みてなされたもので、水硬性物質の水和初期のみなら
ず、長期的にも、６価クロムの溶出を低減できる材料と
これを含有する水硬性組成物等を提供することを目的と
する。DISCLOSURE OF THE INVENTION The present invention has been made in view of the above circumstances, and a material and a material which can reduce the elution of hexavalent chromium not only in the early stages of hydration of a hydraulic substance but also in the long term. An object of the present invention is to provide a hydraulic composition or the like.

【０００５】[0005]

【課題を解決するための手段】本発明者らは、水硬性物
質からの６価クロムの溶出を低減すべく鋭意検討した結
果、ある種の還元性物質が有効であること、また、特に
初期の溶出のみならず長期に渡って溶出抑制効果を持続
する還元性物質を組み合わせると、本発明の目的を達成
できることを見出した。Means for Solving the Problems The present inventors have made intensive studies to reduce the elution of hexavalent chromium from hydraulic substances, and as a result, have found that certain reductants are effective. It has been found that the object of the present invention can be achieved by combining a reducing substance that maintains the dissolution inhibiting effect over a long period of time as well as the dissolution of.

【０００６】即ち、本発明に係る水硬性物質用６価クロ
ム溶出低減剤は、（１）６価クロムの還元性物質を主成
分としてなるものである。該還元性物質は、（２）速効
性の６価クロムの還元性物質と遅効性の６価クロムの還
元性物質からなり、特に、（３）速効性の６価クロムの
還元性物質として第一鉄塩又は硫化物の１種または２
種、及び、遅効性の６価クロムの還元剤として高炉スラ
グ、硫黄、泥炭又は亜炭の１種または２種以上を含有す
るものである。また、（４）６価クロムの還元性物質が
チオ硫酸塩を主成分とするものも含む。次に、本発明は
（５）セメントに上記の還元性物質からなる６価クロム
溶出低減剤を含有してなる水硬性組成物と、（６）６価
クロム溶出低減剤を含有してなる地盤改良材またはグラ
ウト材を提供する。更に、本発明は（７）水硬性物質を
製造する際に、上記（１）〜（４）の６価クロム溶出低
減剤を添加することを特徴とする６価クロム溶出低減方
法をも提供するものである。That is, the hexavalent chromium elution reducing agent for hydraulic substances according to the present invention comprises (1) a hexavalent chromium reducing substance as a main component. The reducing substance is composed of (2) a fast-acting hexavalent chromium reducing substance and a slow-acting hexavalent chromium reducing substance. One or two ferrous salts or sulfides
It contains one or more of blast furnace slag, sulfur, peat or lignite as a seed and a slow-acting hexavalent chromium reducing agent. Also, (4) those in which the reducing substance of hexavalent chromium is mainly composed of thiosulfate are included. Next, the present invention provides (5) a hydraulic composition comprising a cement containing a hexavalent chromium elution reducing agent comprising the above reducing substance, and (6) a ground comprising a hexavalent chromium elution reducing agent. Provide an improving or grouting material. Furthermore, the present invention also provides (7) a method for reducing hexavalent chromium elution, which comprises adding the hexavalent chromium elution reducing agent of (1) to (4) when producing a hydraulic substance. Things.

【０００７】[0007]

【発明の実施の形態】単に、水溶液中の６価クロムを還
元する物質は種々知られているが、本発明が目的とする
のは、セメントを主成分とする水硬性物質が水和してア
ルカリ性を呈する液相中において、初期の溶出を低減す
るとともに、長期に渡り、水和によって徐々に溶出する
６価クロムを不溶化できる材料の提供である。かかる特
殊な環境・期間において、本発明の目的を達成できる還
元性物質を、以下に例示する。DESCRIPTION OF THE PREFERRED EMBODIMENTS Various substances which merely reduce hexavalent chromium in an aqueous solution are known, but an object of the present invention is to hydrate a hydraulic substance mainly composed of cement. An object of the present invention is to provide a material capable of reducing the initial elution in a liquid phase exhibiting alkalinity and insolubilizing hexavalent chromium which is gradually eluted by hydration over a long period of time. The following are examples of reducing substances that can achieve the object of the present invention in such a special environment and period.

【０００８】例えば、亜硫酸アンモニウム、亜硫酸カリ
ウム、亜硫酸カルシウム、亜硫酸ナトリウム、亜硫酸水
素カリウム、亜硫酸ナトリウム等の亜硫酸塩若しくは亜
硫酸水素塩、硫化アンモニウム、硫化カルシウム、硫化
ナトリウム等の硫化物、チオ硫酸ナトリウム、チオ硫酸
カリウム等のチオ硫酸塩、チオ酸塩、二酸化硫黄又は硫
黄等の硫黄化合物、アルカリ金属、マグネシウム、カル
シウム、アルミニウム若しくは亜鉛等のアマルガム、硫
酸第一鉄等の鉄（II）塩又はチタン（III）塩等の金属
塩、一酸化炭素、アルデヒド類、糖類、ギ酸、シュウ酸
等の有機化合物の他、更に、高炉スラグ、泥炭、亜炭、
水素、ヨウ素等が挙げられる。この内、硫酸第一鉄、硫
化アンモニウム等は速効性の還元性物質として、高炉ス
ラグ、硫黄、泥炭、亜炭等は遅効性の還元性物質として
作用する。また、チオ硫酸ナトリウム、チオ硫酸カリウ
ムは短・長期に渡って還元性を持続するので６価クロム
の不溶化に特に有効である。For example, sulfites or bisulfites such as ammonium sulfite, potassium sulfite, calcium sulfite, sodium sulfite, potassium bisulfite and sodium sulfite; sulfides such as ammonium sulfide, calcium sulfide and sodium sulfide; sodium thiosulfate; Thiosulfates such as potassium sulfate, thioates, sulfur compounds such as sulfur dioxide or sulfur, alkali metals, amalgams such as magnesium, calcium, aluminum or zinc, iron (II) salts such as ferrous sulfate or titanium (III) ) In addition to metal salts such as salts, organic compounds such as carbon monoxide, aldehydes, sugars, formic acid, oxalic acid, etc., blast furnace slag, peat, lignite,
Examples include hydrogen and iodine. Among them, ferrous sulfate, ammonium sulfide and the like act as fast-acting reducing substances, and blast furnace slag, sulfur, peat, lignite and the like act as slow-acting reducing substances. In addition, sodium thiosulfate and potassium thiosulfate are particularly effective for insolubilizing hexavalent chromium because they maintain their reducibility over a short and long term.

【０００９】該還元性物質は１種又は２種以上併用でき
るが、速効性の還元性物質は、遅効性の還元性物質と併
用するのが好ましく、初期のみならず長期に渡っても６
価クロムの不溶化に効果を発揮する。高炉スラグを除く
該還元性物質の添加量は、水硬性物質１００重量部に対
し０．１〜１０重量部が好ましく、０．５〜５重量部が
更に好ましい。０．１重量部未満では、６価クロムの溶
出低減効果が十分でなく、１０重量部を超えて使用して
も更なる効果は期待できず、却って、コスト高となる。
また、高炉スラグの添加量は、水硬性物質１００重量部
に対し５〜９００重量部が好ましく、１０〜２５０重量
部が更に好ましい。５重量部未満では、６価クロムの溶
出低減効果が十分でなく、９００重量部を超えて使用し
た場合、水硬性物質の強度発現が低下する恐れがある。The reducing substance can be used alone or in combination of two or more kinds. However, the fast-acting reducing substance is preferably used in combination with a slow-acting reducing substance.
Effective for insolubilizing valent chromium. The amount of the reducing substance except for the blast furnace slag is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, per 100 parts by weight of the hydraulic substance. If the amount is less than 0.1 part by weight, the effect of reducing the dissolution of hexavalent chromium is not sufficient, and even if the amount exceeds 10 parts by weight, no further effect can be expected, and the cost is rather increased.
The amount of the blast furnace slag is preferably 5 to 900 parts by weight, more preferably 10 to 250 parts by weight, per 100 parts by weight of the hydraulic substance. If it is less than 5 parts by weight, the effect of reducing the dissolution of hexavalent chromium is not sufficient, and if it is used in excess of 900 parts by weight, the strength of the hydraulic substance may be reduced.

【００１０】本発明に用いる水硬性物質としては、まず
セメントが挙げられ、ポルトランドセメント、ジェット
セメント、白色セメント、混合セメント、ビーライトセ
メント又はエコセメント等が挙げられる。具体的には、
ポルトランドセメントは普通、早強、中庸熱、超早強、
耐硫酸塩又は白色セメント等であり、ジェットセメント
はカルシウムフルオロアルミネートを含有する超速硬セ
メント、混合セメントはスラグセメント、高炉セメン
ト、フライアッシュセメント、シリカセメント又は石灰
石微粉末含有セメント等である。ビーライトセメントは
低発熱性を有する特殊セメントであり、エコセメントは
都市ゴミ焼却灰、下水汚泥焼却灰等の廃棄物の１種以上
を原料としてなる焼成物であってカルシウムクロロアル
ミネート、カルシウムフルオロアルミネート、カルシウ
ムアルミネートの１種以上を１０〜４０重量％及びカル
シウムシリケートを含む焼成物と石膏を含むセメントで
ある。これらの中でも、特に、高炉セメントは、遅効性
の還元性物質である高炉スラグを含有するため、速効性
の還元性物質との併用が好適である。The hydraulic substance used in the present invention is, for example, cement, such as Portland cement, jet cement, white cement, mixed cement, belite cement, or ecocement. In particular,
Portland cement is usually fast, medium heat, super fast,
Sulfate-resistant or white cement, etc., jet cement is ultra-rapid hardening cement containing calcium fluoroaluminate, and mixed cement is slag cement, blast furnace cement, fly ash cement, silica cement or cement containing fine limestone powder. Belite cement is a special cement with low heat build-up. Eco-cement is a calcined product made from at least one of waste such as municipal waste incineration ash and sewage sludge incineration ash. A cement containing calcined material containing 10 to 40% by weight of at least one of aluminate and calcium aluminate and calcium silicate and gypsum. Among them, blast furnace cement particularly contains blast furnace slag which is a slow-acting reducing substance, and thus is preferably used in combination with a fast-acting reducing substance.

【００１１】また、その他の水硬性物質としては地盤改
良材及びグラウト材等が挙げられる。グラウト材はダム
の基礎、大型地下構造物等の岩盤の強化・止水並びに砂
地盤の液状化対策等を目的として、主にスラリーにして
使用されるものであり、地盤改良材は、軟弱地盤の支持
力の増加、沈下防止等の目的で、地盤の浅層あるいは深
層のせん断力を高めるために、粉体のまま又はスラリー
にして使用されるものである。Other hydraulic materials include a ground improvement material and a grout material. Grout materials are mainly used as slurry for the purpose of strengthening and stopping water in rocks such as dam foundations and large underground structures, and countermeasures against liquefaction of sandy ground. It is used as a powder or as a slurry to increase the shearing force of the shallow or deep layer of the ground for the purpose of increasing the supporting force of the ground and preventing settlement.

【００１２】また、該還元性物質の使用態様は １）セメントに予め混合して水硬性組成物として使用す
る。 ２）グラウト材又は地盤改良材に混合して使用する。 ３）セメントペースト、モルタル、又はコンクリートを
製造する際に添加する。 の何れも利便性等を考慮して選択可能である。一般に、
グラウト材又は地盤改良材は、広範囲の地盤に対して使
用される場合が多く、本発明の６価クロム溶出低減剤を
含有したグラウト材又は地盤改良材は、かかる場合に特
に意義がある。[0012] The mode of use of the reducing substance is as follows: 1) It is preliminarily mixed with cement and used as a hydraulic composition. 2) Mix and use with grout material or soil improvement material. 3) It is added when producing cement paste, mortar, or concrete. Can be selected in consideration of convenience or the like. In general,
The grout material or soil improvement material is often used for a wide range of ground, and the grout material or soil improvement material containing the hexavalent chromium elution reducing agent of the present invention is particularly significant in such a case.

【００１３】該還元性物質の添加量は、グラウト材又は
地盤改良材に混合して使用する場合も、上記と同様、高
炉スラグを除く該還元性物質の添加量は、グラウト材又
は地盤改良材に含まれるセメント１００重量部に対し
て、０．１〜１０重量部が好ましく、０．５〜５重量部
が更に好ましい。また、高炉スラグの添加量は、グラウ
ト材又は地盤改良材に含まれるセメント１００重量部に
対して、５〜９００重量部が好ましく、１０〜２５０重
量部が更に好ましい。このように添加量を限定した理由
は、上記と同様である。尚、本発明において、グラウト
材又は地盤改良材は、公知のものが使用できる。When the reducing substance is added to a grout material or a soil improvement material, the amount of the reducing material excluding blast furnace slag is the same as described above, even when used in a mixture with a grout material or a soil improvement material. Is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the cement contained in. The amount of the blast furnace slag is preferably 5 to 900 parts by weight, more preferably 10 to 250 parts by weight, based on 100 parts by weight of the cement contained in the grout material or the ground improvement material. The reason for limiting the amount of addition in this way is the same as above. In the present invention, known grout materials or ground improvement materials can be used.

【００１４】本発明に係る水硬性組成物、グラウト材又
は地盤改良材は、種々の物性の改善のために必要に応じ
て、高炉スラグ等の潜在水硬性物質、石炭灰、シリカヒ
ューム若しくは各種の溶融スラグ等のポゾラン物質、消
石灰、炭酸カルシウム若しくは各種の石膏等のカルシウ
ム化合物などの混和材、又は、ＡＥ剤、減水剤、ＡＥ減
水剤、高性能ＡＥ減水剤、凝結調節剤、流動化剤若しく
は防錆剤等の公知の混和剤を併用することもできる。The hydraulic composition, grout material or soil improvement material according to the present invention may be used, if necessary, for improving various physical properties, such as a latent hydraulic material such as blast furnace slag, coal ash, silica fume or various kinds of materials. Pozzolanic substances such as molten slag, admixtures such as slaked lime, calcium carbonate or calcium compounds such as various plasters, or AE agents, water reducing agents, AE water reducing agents, high-performance AE water reducing agents, setting regulators, fluidizing agents or A known admixture such as a rust preventive may be used in combination.

【００１５】[0015]

【実施例】以下に、本発明の実施例を示すが、これらは
例示であり、本発明を限定するものではない。 １．使用材料 普通セメント：イギリス製セメント（総クロム含有量７
０ｐｐｍ、６価クロム含有量２９．５ｐｐｍ） 硫酸第一鉄：試薬特級（関東化学社製） 高炉スラグ：商品名 エスメント（新日本製鐵社製） 硫黄：２００メッシュ品（細井化学工業社製） チオ硫酸ナトリウム：試薬特級（関東化学社製）EXAMPLES Examples of the present invention will be described below, but these are exemplifications and do not limit the present invention. 1. Materials used Ordinary cement: British cement (total chromium content 7)
0 ppm, hexavalent chromium content 29.5 ppm) Ferrous sulfate: Special grade reagent (Kanto Chemical) Blast furnace slag: Trade name Esment (Nippon Steel) Sulfur: 200 mesh (Hosoi Chemical) Sodium thiosulfate: reagent grade (Kanto Chemical Co., Ltd.)

【００１６】２．試験方法 （１）セメントからの６価クロム溶出試験 表１に示す配合の普通セメントと各種の還元性物質を用
い、環境庁告示第１３号「産業廃棄物に含まれる金属等
の検定方法」に準拠して、セメントからの６価クロムの
溶出試験を行った。試験結果を表１に示す。2. Test method (1) Hexavalent chromium elution test from cement Using the ordinary cement and the various reducing substances shown in Table 1, complying with the Notification of the Environment Agency No. 13 "Testing methods for metals and the like contained in industrial waste". In accordance with the above, a dissolution test of hexavalent chromium from cement was performed. Table 1 shows the test results.

【００１７】[0017]

【表１】 [Table 1]

【００１８】表１から分かるように、全ての実施例にお
いて、セメントからの６価クロムの溶出量が、比較例１
と比べ３０％以下に低減している。本試験では、セメン
トからの６価クロムの溶出は初期の溶出であるため、速
効性の還元性物質(硫酸第一鉄)による溶出低減効果(実
施例１、２及び３)が遅効性の還元性物質（硫黄及び高
炉スラグ）による溶出低減効果(実施例４，５，７，８
及び９)よりも大きいことが分かる。また特に、チオ硫
酸ナトリウムを使用した実施例６、１２及び１３は６価
クロムの溶出量が未検出であり、チオ硫酸ナトリウムは
低添加量で顕著な低減効果を有することが分かる。As can be seen from Table 1, in all Examples, the amount of hexavalent chromium eluted from the cement was less than Comparative Example 1.
Is reduced to 30% or less. In this test, since the elution of hexavalent chromium from cement is the initial elution, the elution reduction effect (Examples 1, 2 and 3) by the fast-acting reducing substance (ferrous sulfate) is reduced by the slow-acting reduction. Of elution by volatile substances (sulfur and blast furnace slag) (Examples 4, 5, 7, 8)
And 9). In particular, in Examples 6, 12, and 13 using sodium thiosulfate, the elution amount of hexavalent chromium was not detected, and it can be seen that sodium thiosulfate has a remarkable reduction effect at a low addition amount.

【００１９】（２）改良土からの６価クロム溶出試験 表３に示す配合の普通セメントと還元性物質からなる各
種の固化材を粉体のまま、又は、水／固化材重量比１に
調整したスラリー状態で、表２に示す特性を有する関東
ローム又は砂質土（以下、対象土という）に混合し（以
下、粉体混合又はスラリー混合という）、改良土を作成
した。粉体混合とスラリー混合を実施したのは、前記し
たように、当該固化材をグラウト材又は地盤改良材とし
て現場施工する場合、現実に、両方の混合方法が使用さ
れるからである。具体的には、粉体混合の場合は、含水
比１１１．６％の関東ローム又は含水比２７．５％の砂
質土１ｍ3当たり固化材１００ｋｇを混合し、地盤工学
会基準ＪＧＳ Ｔ ８１１−１９９０に準拠して、また、
スラリー混合の場合は、含水比１１１．６％の関東ロー
ム又は含水比４０．９％の砂質土１ｍ3当たり固化材２
００ｋｇを混合し、地盤工学会基準ＪＧＳ Ｔ ８２１−
１９９０に準拠して改良土を作成した。改良土からの６
価クロム溶出試験は、環境庁告示第４６号「土壌の汚染
に係る環境基準について」に準拠して、材齢７日及び６
ヶ月における６価クロムの溶出試験を行った。また溶出
試験の前処理として、改良土を未乾燥のまま又は４０℃
で２４時間乾燥を施した。かかる前処理を実施したの
は、実際の改良土の存在状態を想定したものである。改
良土を未乾燥のまま又は４０℃で２４時間乾燥して試験
に供した場合の試験結果は、それぞれ、表４及び表６又
は表５及び表７に示す。(2) Hexavalent chromium elution test from improved soil Various solidified materials composed of ordinary cement and a reducing substance having the composition shown in Table 3 were used as powder or adjusted to a water / solidified material weight ratio of 1. The resulting slurry was mixed with Kanto loam or sandy soil (hereinafter referred to as target soil) having the characteristics shown in Table 2 (hereinafter referred to as powder mixing or slurry mixing) to prepare an improved soil. The reason why the powder mixing and the slurry mixing are performed is that, as described above, when the solidified material is applied on site as a grout material or a ground improvement material, both mixing methods are actually used. Specifically, in the case of powder mixing, 100 kg of solidified material is mixed per 1 m 3 of Kanto loam with a moisture content of 111.6% or sandy soil with a moisture content of 27.5%, and the Japan Geotechnical Society standard JGS T 811- In accordance with 1990,
For slurry mixing, water content of 111.6% of the Kanto loam or hydrous 40.9% of the sandy soil 1 m 3 per solidified material 2
00kg, and the Japan Geotechnical Society standard JGS T821-
Improved soil was prepared according to 1990. 6 from improved soil
The chromium (II) leaching test was carried out according to the Notification of the Environment Agency No. 46, “Environmental Standards for Soil Contamination,” with the age of 7 days and 6 days.
A 6 month chromium (VI) dissolution test was performed. As a pretreatment for the dissolution test, leave the improved soil wet or at 40 ° C.
For 24 hours. The reason why such pretreatment was performed is assuming the actual condition of the improved soil. Table 4 and Table 6 or Table 5 and Table 7, respectively, show the test results when the improved soil was subjected to a test as it was or was dried at 40 ° C. for 24 hours.

【００２０】[0020]

【表２】 [Table 2]

【００２１】[0021]

【表３】 [Table 3]

【００２２】[0022]

【表４】 [Table 4]

【００２３】[0023]

【表５】 [Table 5]

【００２４】[0024]

【表６】 [Table 6]

【００２５】[0025]

【表７】 [Table 7]

【００２６】表４（材齢７日、未乾燥試料）から、速効
性の還元性物質（硫酸第一鉄）のみを含有する固化材を
使用した場合（実施例１４、１５、２１、３０、３１及
び３７）は、還元性物質無添加の固化材を使用した場合
（比較例２、３、４及び５）と比べ、６価クロムの溶出
低減効果はあるものの、その程度は低い。一方、速効性
と遅効性の還元性物質を併用した場合（実施例１６、２
０、２６、２７、３２、３６、４２及び４３）は、速効
性の還元性物質のみの場合より、６価クロムの溶出低減
効果が格段に高い。これは、速効性の還元性物質のみを
含有する固化材の場合、速効性の還元性物質の自己酸化
等により還元作用が低下してしまうので、材齢の経過
（水和の進行）によって6価クロムが徐々に溶出してく
る場合には溶出低減効果が小さいためであり、遅効性の
還元性物質を併用することによってこの点を補い、6価
クロムの溶出低減に効果を発揮したものである。つま
り、速効性の還元性物質に遅効性の還元性物質を併用す
ることにより、十分な低減効果が得られることが分か
る。また表６（材齢６ヶ月、未乾燥試料）に示すよう
に、遅効性の還元性物質を用いることで（実施例６５〜
７１）、併用、単独使用の如何に関わらず、長期材齢
（６ヶ月）における改良土からも６価クロムの溶出が認
められず、不溶化の効果が長期に渡って作用しているこ
とが分かる。ところで、長期材齢における改良土からの
６価クロムの溶出については遅効性の還元性物質単独で
も溶出低減効果が得られているが、地盤改良を行う際に
は固化材を粉体のままあるいはスラリーとして使用する
ことから、改良土がまだ固まらない状態及び初期の材齢
においては、初期の6価クロムの溶出が懸念される。こ
のため初期及び長期に渡って溶出する６価クロムを不溶
化するためには、速効性の還元性物質と遅効性の還元物
質の併用が好ましい。更に、チオ硫酸ナトリウムは併用
（実施例２８、２９、４４、４５、７０及び７１）のみ
ならず単独（実施例２４、２５、４０、４１、６６及び
６７）でも、低減効果が高い。従って、表１に記載の実
施例６の結果と合わせてチオ硫酸ナトリウムは、単独使
用でも初期・長期にわたって高い低減効果を示すことが
分かる。From Table 4 (7 days old, undried sample), when a solidified material containing only a fast-acting reducing substance (ferrous sulfate) was used (Examples 14, 15, 21, 30, 30) 31 and 37) have an effect of lowering the dissolution of hexavalent chromium, but to a lesser extent than the case where a solidifying material without the addition of a reducing substance is used (Comparative Examples 2, 3, 4 and 5). On the other hand, when a fast-acting and a slow-acting reducing substance are used in combination (Examples 16 and 2)
0, 26, 27, 32, 36, 42 and 43) are much more effective in reducing the dissolution of hexavalent chromium than in the case of using only a fast-acting reducing substance. This is because, in the case of a solidified material containing only a fast-acting reducing substance, the reducing action is reduced due to the auto-oxidation of the fast-acting reducing substance and the like. This is because when the valent chromium gradually elutes, the effect of reducing elution is small, and this is compensated for by using a slow-acting reducing substance in combination, and the effect of reducing the elution of hexavalent chromium is demonstrated. is there. In other words, it can be seen that a sufficient reduction effect can be obtained by using a slow-acting reducing substance in combination with a fast-acting reducing substance. In addition, as shown in Table 6 (6 months old, undried sample), by using a slow-acting reducing substance (Examples 65 to 65)
71), no dissolution of hexavalent chromium was observed from the improved soil at the long-term age (6 months) regardless of whether it was used in combination or alone, indicating that the effect of insolubilization was acting for a long time. . By the way, with respect to the dissolution of hexavalent chromium from the improved soil at the long-term age, the effect of reducing dissolution can be obtained even with a slow-acting reducing substance alone. Since the slurry is used as a slurry, in the state where the improved soil is not yet solidified and in the early age, there is a concern that the elution of hexavalent chromium in the initial stage. Therefore, in order to insolubilize hexavalent chromium which elutes over an initial period and a long period, a combination of a fast-acting reducing substance and a slow-acting reducing substance is preferable. Furthermore, sodium thiosulfate has a high reduction effect not only when used in combination (Examples 28, 29, 44, 45, 70 and 71) but also when used alone (Examples 24, 25, 40, 41, 66 and 67). Therefore, it can be seen that sodium thiosulfate shows a high reduction effect over the initial and long term even when used alone, in combination with the results of Example 6 shown in Table 1.

【００２７】表５及び表７に示す結果からも、上記と同
様のことがいえる。従って、改良土が湿潤状態、乾燥状
態何れであっても、本発明の６価クロム溶出低減剤は、
高い効果を有することが分かる。The results shown in Tables 5 and 7 indicate the same as above. Therefore, regardless of whether the improved soil is in a wet state or a dry state, the hexavalent chromium elution reducing agent of the present invention is:
It turns out that it has a high effect.

【００２８】[0028]

【発明の効果】本発明によれば、セメントの水和初期の
みならず、長期的にも、セメントからの６価クロムの溶
出を低減できる６価クロム溶出低減剤とこれを含有する
水硬性組成物等を提供できる。According to the present invention, a hexavalent chromium elution reducing agent capable of reducing the elution of hexavalent chromium from cement not only at the beginning of hydration of the cement but also for a long period of time, and a hydraulic composition containing the same Things can be provided.

───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） // Ｃ０４Ｂ 103:60 111:70 Ｃ０９Ｋ 107:00 (72)発明者 野口 雅朗 千葉県佐倉市大作二丁目４番２号 秩父小 野田株式会社中央研究所内 (72)発明者 礒田 英典 千葉県佐倉市大作二丁目４番２号 秩父小 野田株式会社中央研究所内 (72)発明者 橋本 真幸 千葉県佐倉市大作二丁目４番２号 秩父小 野田株式会社中央研究所内 (72)発明者 平尾 宙 千葉県佐倉市大作二丁目４番２号 秩父小 野田株式会社中央研究所内 Ｆターム(参考） 4G012 MB11 MB12 PA14 PA29 4H026 CA01 CA05 CB01 CB02 CB07 CC06 ──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat ゛ (Reference) // C04B 103: 60 111: 70 C09K 107: 00 (72) Inventor Masao Noguchi Daisaku 2-chome, Sakura City, Chiba Prefecture No.4-2, Chichibu Onoda Noda Co., Ltd. Central Research Laboratory (72) Inventor Hidenori Isota 2-4-2 Daisaku, Sakura City, Chiba Prefecture Chichibu Onoda Noda Co., Ltd. Central Research Laboratory (72) Inventor Masayuki Hashimoto Chiba Pref. 2-4-2, Chichibu Onoda Noda Central Research Laboratory (72) Inventor Sora Hirao 2-4-2 Daisaku, Sakura-shi, Chiba Prefecture Chichibu Onoda Central Research Laboratory F-term (reference) 4G012 MB11 MB12 PA14 PA29 4H026 CA01 CA05 CB01 CB02 CB07 CC06

Claims (7)

【特許請求の範囲】[Claims] 【請求項１】 ６価クロムの還元性物質を主成分とする
水硬性物質用６価クロム溶出低減剤。1. A hexavalent chromium elution reducing agent for a hydraulic substance, comprising a hexavalent chromium reducing substance as a main component. 【請求項２】 速効性の６価クロムの還元性物質と遅効
性の６価クロムの還元性物質からなる請求項１に記載の
水硬性物質用６価クロム溶出低減剤。2. The hexavalent chromium elution reducing agent for hydraulic substances according to claim 1, comprising a fast-acting hexavalent chromium reducing substance and a slow-acting hexavalent chromium reducing substance. 【請求項３】 速効性の６価クロムの還元性物質が第一
鉄塩又は硫化物の１種以上、及び、遅効性の６価クロム
の還元剤が高炉スラグ、硫黄、泥炭又は亜炭の１種以上
を含む請求項１又は２に記載の水硬性物質用６価クロム
溶出低減剤。3. The fast-acting hexavalent chromium reducing substance is one or more of ferrous salts or sulfides, and the slow-acting hexavalent chromium reducing agent is one of blast furnace slag, sulfur, peat or lignite. The hexavalent chromium elution reducing agent for hydraulic substances according to claim 1, comprising at least one species. 【請求項４】 ６価クロムの還元性物質がチオ硫酸塩を
主成分とする水硬性物質用６価クロム溶出低減剤。4. A hexavalent chromium elution reducing agent for hydraulic substances, wherein the hexavalent chromium reducing substance is mainly thiosulfate. 【請求項５】 セメントに請求項１〜４に記載の水硬性
物質用６価クロム溶出低減剤を含有してなる水硬性組成
物。5. A hydraulic composition comprising a cement containing the hexavalent chromium elution reducing agent for hydraulic substances according to claim 1. 【請求項６】 請求項１〜４に記載の水硬性物質用６価
クロム溶出低減剤を含有してなる地盤改良材又はグラウ
ト材。6. A ground improvement material or grout material containing the hexavalent chromium elution reducing agent for hydraulic substances according to claim 1. 【請求項７】 水硬性物質を製造する際に、請求項１〜
４に記載の水硬性物質用６価クロム溶出低減剤を添加す
ることを特徴とする６価クロム溶出低減方法。7. The method for producing a hydraulic substance according to claim 1,
A method for reducing the dissolution of hexavalent chromium, comprising adding the agent for reducing dissolution of hexavalent chromium for hydraulic substances according to 4.
JP26272598A 1998-09-17 1998-09-17 Hexavalent chromium leach reducing agent for hydraulic material, and method for reducing hexavalent chromium leach Pending JP2000086322A (en)

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