WO1984002900A1 - Procede de reduction de chrome inducteur d'eczema dans le ciment par l'addition de sulfate ferreux, un additif comportant du sulfate ferreux et l'utilisation de l'additif - Google Patents

Procede de reduction de chrome inducteur d'eczema dans le ciment par l'addition de sulfate ferreux, un additif comportant du sulfate ferreux et l'utilisation de l'additif Download PDF

Info

Publication number
WO1984002900A1
WO1984002900A1 PCT/SE1984/000011 SE8400011W WO8402900A1 WO 1984002900 A1 WO1984002900 A1 WO 1984002900A1 SE 8400011 W SE8400011 W SE 8400011W WO 8402900 A1 WO8402900 A1 WO 8402900A1
Authority
WO
WIPO (PCT)
Prior art keywords
cement
gypsum
ferrogypsum
ferrous sulfate
green salt
Prior art date
Application number
PCT/SE1984/000011
Other languages
English (en)
Inventor
Per Norelius
Original Assignee
Cementa Ab
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 Cementa Ab filed Critical Cementa Ab
Priority to AU24342/84A priority Critical patent/AU2434284A/en
Publication of WO1984002900A1 publication Critical patent/WO1984002900A1/fr

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
    • C04B11/00—Calcium sulfate cements
    • 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
    • C04B22/0006—Waste inorganic materials
    • 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
    • C04B22/142—Sulfates
    • C04B22/149—Iron-sulfates
    • 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
    • C04B7/00—Hydraulic cements
    • C04B7/22—Iron ore cements ; Iron rich cements, e.g. Ferrari cements, Kühl cements
    • 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
    • C04B2111/10—Compositions or ingredients thereof characterised by the absence or the very low content of a specific material
    • C04B2111/1075—Chromium-free or very low chromium-content materials
    • C04B2111/1081—Chromium VI, e.g. for avoiding chromium eczema

Definitions

  • Portland cement always contains a certain amount of readily soluble hexavalent chromium in the form of chromates, usu- ally 10-20 ppm Cr , stemming from” the raw material and in smaller amounts from the fuel, the kiln lining and the various machines.
  • This chromium produces eczema in brick ⁇ layers and concrete workers among others.
  • a known and tested additive for reducing the content of easily soluble hexavalent chromium in the concrete, and thus reducing the risk of chromium contact eczema, is divalent iron in the form of ferrous sulfate.
  • Ferrous sulfate is present in large amounts in the form of so-called green salt, a waste product from certain chemical and hydrometallurgical process industries.
  • green salt a waste product from certain chemical and hydrometallurgical process industries.
  • 3-4 tons of green salt are obtained for example for each ton of titanium dioxide.
  • a small amount of this can be used for water purification, but the major portion is deposited as waste or is pumped into the sea.
  • Green salt is such ferrous sulfate which leaves a precipita ⁇ tion process after a varying degree of mechanical dehydra- ti ⁇ n by filtering and possibly centrifuging.
  • the major component of the green salt is ferrous sulfate with 7 hygro ⁇ scopic water, FeS0 4 «7H 2 0, with varying amounts of impurities and a moisture content of 2-25 % by weight depending on the dehydration method. Centrifuged green salt has the consis- tency of wet snow.
  • Green salt has been approved as a concrete additive and is sold in 25 kg plastic bags for manual addition in conjunc ⁇ tion with the mixing of concrete.
  • green salt can have a negative effect on the grinding pro ⁇ cess itself by hardened deposits in the mill with tendencies for blockage especially at the mill inlet.
  • an excessively high water content of the ferrous sulfate can cause the chromate-reducing effect to be lossed when the green salt with an excess of water is subjected in the cement mill to an alkaline environment and high temper ⁇ ature.
  • the handling problem can be avoided by dumping the salt directly into a tank for dissolving and then add the ferrous sulfate solution to the process.
  • a corresponding technique has also been tried in the cement industry by spraying a saturated aqueous solution of the green salt into the cement mill, but this produced insufficient chromate reduction in the concrete.
  • Another method which has been tested is to pump into the mill a slurry consisting of undissolved ferrous sulfate and saturated ferrous sulfate solution, but this process did not produce sufficient chromate reduction either.
  • the present invention intends to produce cement with an additive of green salt in a mechanized and automated process with already existing equipment, by a method which does not produce the negative effects on the cement mill operation and which produces sufficient chro ate reduction to eliminate the risk of eczema.
  • Cement refers here to all hydraulic binders and mortar products containing Portland cement clinker as the major component, 1-10 % by weight gypsum, CaS0 4 «2H-0 as a regulator of setting time and varying amounts of additives such as limestone, ash, slag and silicon powder, e.g. an amorphous, finely dispersed kieselguhr from the manufacture of silicon, ferrosilicon and ferrochromium.
  • Green salt refers to a wet to moist salt containing 15-20 % iron in the form of FeS0 4 «7H 0 and 2-25 % by weight of non- chemically bonded water.
  • the invention is based on replacing the ordinary gypsum • component in the cement milling with a mixture of gypsum and green salt, called ferrogypsum in the following, which is responsible in the process both for controlling the setting time and chromate reduction.
  • the gypsum can be natural gypsum or so-called chemical gypsum, a by-product of certain chemical processes. especially the production of phosphoric acid.
  • the granules of chemical gypsum are normally fine and can be easily mixed with green salt into a homogeneous mixture which will not separate during handling up to the cement mill.
  • natural gypsum one should select a quality witha low proportion of heavy particles over about 20 mm, so that the separation of gypsum and green salt will be minimized.
  • the composition of the ferrogypsum must be such that the amount of sulfate which regulates the setting time and the amount of divalent iron for reducing chromates have a certain relative proportion in view of the desired sulfate content in the finished cement, the original content of easily soluble chromate and the desired chromate reduction.
  • the sulfate content and the chromate content in the cement vary from case to case, but have been shown to be virtually constant over time for a particular production unit. It is therefore possible to maintain the composition of the ferro ⁇ gypsum once it has been determined.
  • a suitable addition of ferrous sulfate is 3-12 kg FeSO. «7H 2 0 per ton of finished cement, depending on the original con ⁇ tent of Cr in the cement clinker and the desired chromate reduction.
  • the addi ⁇ tion of gypsum is reduced by 0.6 parts gypsum for each part ferrous sulfate heptahydrate added.
  • the proportion of green salt in the ferrogypsum can also be reduced if the original content of Cr in the cement is lower than 10 ppm or if the chromate reduction is not to be carried as far.
  • the mixing in of green salt in the ferrogypsum can be calculated from the size of the gypsum addition if it is initially greater or less than 50 kg per ton of cement.
  • the proportion of green salt in the ferrogypsum can then vary from case to case between 2 and 90 % by weight, preferably between 5 and 25 % by weight.
  • the ferrogypsum has good storage stability and the cement grinding process is rela- tively insensitive to fluctuations in the composition of the ferrogypsum, due to inhomogeneity. This allows the ferrogypsum to be prepared with simple equipment and at the.most advantageous location for transport, for example at the factory or delivery location for gypsum or green salt, at the reloading terminal or at the cement factory.
  • the preparation of the ferrogypsum can be done by laying out a specific quantity of gypsum on a flat supporting surface in a layer about one meter thick. On top of this there is then laid a layer of a certain amount of green salt corresponding to the desired mixing proportions.
  • the materials can be laid out with a bucket loader and the mixture can be homogenized by redigging with the loader, whereafter the mixture is loaded into a bin for transport to the next station, which can be a ship or a transport vehicle, intermediate storage plant or dosing bin for feeding into a cement mill.
  • the ferrogypsum thus produced can then be used as a re ⁇ placement for gypsum in the making of cement after recal ⁇ culating the dosing as specified above.
  • the chromium contents refer to analyses done after two minutes of shaking of equal amounts of cement and water.
  • the ferrogypsum had better handling pro ⁇ perties than both green salt and gypsum individually due to less dust and easy passage through loading bins and shuts.
  • the invention provides a method for using green salt as a chromate reducing raw material because - the ferrogypsum has significantly better handling charac ⁇ teristics than green salt, and at least equally good handling characteristics as gypsum;
  • the ferrogypsum does not negatively affect the operation of the cement mill with baked-on deposits and the like, as is the case when using green salt and gypsum individu ⁇ ally;
  • the divalent iron in the ferrogypsum is only oxidated to an insignificant degree to trivalent iron during the milling process, which can be done by direct addition of wet green salt and gypsum individually.
  • the invention permits the replacement of two additives by a single additive which provides appreciable advantages as regards transport and economy. No extra investments are required for the addition of ferrous sulfate in each produc ⁇ tion line, as is the case with separate addition of ferrous sulfate and gypsum. Rather, existing equipment is used.
  • OMPI done in fewer and larger boats, and the existing receiving and storage system for gypsum at the cement plant can be used.
  • the present invention thus provides a simple method for producing a cement with significantly reduced risk of chromium eczema, without changing existing production lines, by using an inexpensive waste product, and the finished cement has equally good properties as cement without the addition, and at the same time without risk of causing chromium eczema.

Landscapes

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

Abstract

Afin de réduire d'eczéma dû au chrome lorsque l'on travaille avec le ciment, on réduit le chrome hexavalent dans le ciment avec du sulfate ferreux sous forme de ferrogypse. On prépare du ferrogypse en mélangeant du sel vert, un déchet de la production entre autre du bioxyde de titane, dans un état mouillé sans séchage ou granulation précédante avec des proportions prédéterminées de gypse. On utilise le ferrogypse dans la fabrication du ciment comme produit du gypse ordinaire et on l'ajoute au procédé de concassage du ciment avec le système de dosage existant pour le gypse. Afin de réduire la teneur en chrome hexavalent aisément soluble d'environ 10 ppm à environ 0,5 ppm, il faut additionner environ 5 à 10 kg de sel vert par tonne de ciment. Avec un ajout normal de 50 kg par tonne de ciment, le ferrogypse devrait être formé à 10 % en poids de sel vert et à 90 % en poids de gypse et être ajouté à raison de 52 kg par tonne de ciment.
PCT/SE1984/000011 1983-01-20 1984-01-17 Procede de reduction de chrome inducteur d'eczema dans le ciment par l'addition de sulfate ferreux, un additif comportant du sulfate ferreux et l'utilisation de l'additif WO1984002900A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU24342/84A AU2434284A (en) 1983-01-20 1984-01-17 Ferrogypsum in the manufacture of cement

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE8300283 1983-01-20

Publications (1)

Publication Number Publication Date
WO1984002900A1 true WO1984002900A1 (fr) 1984-08-02

Family

ID=20349686

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1984/000011 WO1984002900A1 (fr) 1983-01-20 1984-01-17 Procede de reduction de chrome inducteur d'eczema dans le ciment par l'addition de sulfate ferreux, un additif comportant du sulfate ferreux et l'utilisation de l'additif

Country Status (10)

Country Link
EP (1) EP0133434A1 (fr)
KR (1) KR840007392A (fr)
AU (1) AU2434284A (fr)
DD (1) DD217503A5 (fr)
GR (1) GR79711B (fr)
IT (1) IT1173095B (fr)
PL (1) PL245835A1 (fr)
RO (1) RO90804B (fr)
WO (1) WO1984002900A1 (fr)
YU (1) YU9684A (fr)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1092690A1 (fr) 1999-10-12 2001-04-18 Povazská cementáren, a.s. Procédé de fabrication de ciment ayant une teneur réduite en chrome
EP1440954A1 (fr) * 2003-01-25 2004-07-28 Ferro Duo GmbH Liant hydraulique avec une teneur en chromate réduite
EP1533287A1 (fr) * 2003-11-21 2005-05-25 W.R. Grace & Co.-Conn. Dispersion comprenant sulfate d'étain ou sulfate de fer pour réduire le chromate en ciment
EP1544182A1 (fr) * 2003-12-12 2005-06-22 Kehrmann Alexander Liant hydraulique
CN100441533C (zh) * 2004-02-04 2008-12-10 格雷斯公司 一种减少水泥组合物中六价铬的方法
CZ300050B6 (cs) * 2005-09-30 2009-01-21 Peringer@František Zpusob úpravy manipulacních vlastností heptahydratovaného síranu železnatého, zejména snížení jeho hygroskopických vlastností
ES2316283A1 (es) * 2007-05-31 2009-04-01 Fertisac, S.L. Procedimiento de fabricacion de sulfato ferroso granulado como aditivo para cementeras.
US7717999B1 (en) 2008-12-24 2010-05-18 The National Titanium Dioxide, Co., Ltd. (Cristal) Titanium production waste byproduct as partial cement replacement
EP1648840B2 (fr) † 2003-07-17 2019-01-09 crenox GmbH Agent de reduction destine aux chromates solubles presents dans du ciment et procedes de production dudit agent de reduction
CN113060948A (zh) * 2021-04-01 2021-07-02 重庆康尼睿能商贸有限公司 一种水泥生料及水泥的制备方法
CN113072318A (zh) * 2021-04-25 2021-07-06 湖北新洋丰新型建材科技有限公司 一种球状磷石膏及其制备方法和应用

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4321077A1 (de) 1993-06-24 1995-01-05 Dyckerhoff Ag Verfahren zur Depression der Allergien verursachenden Wirkung von wasserlöslichem Cr·V··I· in Zementen und/oder zementhaltigen Zubereitungen
US8076175B2 (en) 2008-02-25 2011-12-13 Suniva, Inc. Method for making solar cell having crystalline silicon P-N homojunction and amorphous silicon heterojunctions for surface passivation
CN111099849A (zh) * 2019-12-26 2020-05-05 安徽迪诺环保新材料科技有限公司 一种钛石膏建筑水泥砂浆及其制备方法
CN111807749B (zh) * 2020-06-11 2022-04-12 内蒙古同佳技术发展有限公司 一种六价铬还原剂及其制备方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2307270A (en) * 1940-08-04 1943-01-05 Mellon Inst Of Ind Res Building material
US3425892A (en) * 1965-10-22 1969-02-04 Grace W R & Co Cement set retarder
EP0054314A1 (fr) * 1980-12-17 1982-06-23 Aktieselskabet Aalborg Portland-Cement-Fabrik Procédé et installation pour la fabrication d'une composition de ciment sec
WO1984001942A1 (fr) * 1982-11-17 1984-05-24 Aalborg Portland Cement Procedes de production d'un melange de ciment frais et d'un produit d'hydrate de sulfate ferreux s'ecoulant librement ainsi que les produits prepares par ces procedes

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2307270A (en) * 1940-08-04 1943-01-05 Mellon Inst Of Ind Res Building material
US3425892A (en) * 1965-10-22 1969-02-04 Grace W R & Co Cement set retarder
EP0054314A1 (fr) * 1980-12-17 1982-06-23 Aktieselskabet Aalborg Portland-Cement-Fabrik Procédé et installation pour la fabrication d'une composition de ciment sec
WO1984001942A1 (fr) * 1982-11-17 1984-05-24 Aalborg Portland Cement Procedes de production d'un melange de ciment frais et d'un produit d'hydrate de sulfate ferreux s'ecoulant librement ainsi que les produits prepares par ces procedes

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Chemical Abstracts, Vol 88 (1978) abstract No. 140777a, Nordisk Betong, 1977, 6, 28-30. *
Chemical Abstracts, Vol.79 (1973), abstract No. 96214c, Acta Derum - Venereol, 1973, 53 (4), 267-270. *

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1092690A1 (fr) 1999-10-12 2001-04-18 Povazská cementáren, a.s. Procédé de fabrication de ciment ayant une teneur réduite en chrome
EP1440954A1 (fr) * 2003-01-25 2004-07-28 Ferro Duo GmbH Liant hydraulique avec une teneur en chromate réduite
EP1648840B2 (fr) † 2003-07-17 2019-01-09 crenox GmbH Agent de reduction destine aux chromates solubles presents dans du ciment et procedes de production dudit agent de reduction
JP4712719B2 (ja) * 2003-11-21 2011-06-29 ダブリュー・アール・グレイス・アンド・カンパニー−コネチカット 硫酸塩分散クロム酸塩還元剤
EP1533287A1 (fr) * 2003-11-21 2005-05-25 W.R. Grace & Co.-Conn. Dispersion comprenant sulfate d'étain ou sulfate de fer pour réduire le chromate en ciment
US7128782B2 (en) 2003-11-21 2006-10-31 W.R. Grace & Co.-Conn. Sulfate dispersion chromate reducer
JP2007522061A (ja) * 2003-11-21 2007-08-09 ダブリュー・アール・グレイス・アンド・カンパニー−コネチカット 硫酸塩分散クロム酸塩還元剤
EP2143698A1 (fr) * 2003-11-21 2010-01-13 W.R. Grace & Co.-Conn. Dispersion comprenant sulfate d'étain ou sulfate de fer pour réduire le chromate en ciment
EP1544182A1 (fr) * 2003-12-12 2005-06-22 Kehrmann Alexander Liant hydraulique
WO2005056491A1 (fr) * 2003-12-12 2005-06-23 Kerr-Mcgee Pigments International Gmbh Liant hydraulique et reducteur de chromate et utilisation correspondante
CN100441533C (zh) * 2004-02-04 2008-12-10 格雷斯公司 一种减少水泥组合物中六价铬的方法
CZ300050B6 (cs) * 2005-09-30 2009-01-21 Peringer@František Zpusob úpravy manipulacních vlastností heptahydratovaného síranu železnatého, zejména snížení jeho hygroskopických vlastností
ES2316283A1 (es) * 2007-05-31 2009-04-01 Fertisac, S.L. Procedimiento de fabricacion de sulfato ferroso granulado como aditivo para cementeras.
US7824322B2 (en) 2008-12-24 2010-11-02 The National Titanium Dioxide, Co. Ltd. (Cristal) Titanium production waste byproduct as partial cement replacement
US7717999B1 (en) 2008-12-24 2010-05-18 The National Titanium Dioxide, Co., Ltd. (Cristal) Titanium production waste byproduct as partial cement replacement
CN113060948A (zh) * 2021-04-01 2021-07-02 重庆康尼睿能商贸有限公司 一种水泥生料及水泥的制备方法
CN113072318A (zh) * 2021-04-25 2021-07-06 湖北新洋丰新型建材科技有限公司 一种球状磷石膏及其制备方法和应用

Also Published As

Publication number Publication date
YU9684A (en) 1986-08-31
IT1173095B (it) 1987-06-18
KR840007392A (ko) 1984-12-07
IT8419258A0 (it) 1984-01-20
AU2434284A (en) 1984-08-15
EP0133434A1 (fr) 1985-02-27
DD217503A5 (de) 1985-01-16
PL245835A1 (en) 1985-01-30
RO90804A (fr) 1987-01-30
RO90804B (ro) 1987-01-31
GR79711B (fr) 1984-10-31

Similar Documents

Publication Publication Date Title
WO1984002900A1 (fr) Procede de reduction de chrome inducteur d'eczema dans le ciment par l'addition de sulfate ferreux, un additif comportant du sulfate ferreux et l'utilisation de l'additif
US5084102A (en) Cement, method of preparing such cement and method of making products using such cement
US3947284A (en) Method for solidifying sludge
USRE31682E (en) Process for manufacturing concrete of high corrosion resistance
US4354876A (en) Utilization of dry scrubber waste materials
EP0160746B1 (fr) Composition sèche de ciment
FI72962C (fi) Tillsatsblandning foer betong och bruk, foerfarande foer dess framstaellning och dess anvaendning.
WO2022057104A1 (fr) Procédé de préparation d'un matériau de remplissage de mine en utilisant des résidus de métal lourd cimentés par des déchets solides dans l'industrie de l'acier
US3427175A (en) Accelerator for portland cement
EP0619276A1 (fr) Ciment, procédé pour sa préparation et procédé pour la fabrication de produits utilisant ce ciment
EP0078315A4 (fr) Composition additive pour materiaux de ciment portland.
CN109265120A (zh) 一种矿山充填材料及其制备装置和制备方法及矿山充填用胶结剂料浆
AU2260183A (en) A method of improving the properties of a powder
NO150634B (no) Sementholdige blandinger og fremgangsmaate for deres fremstilling
CN110482966B (zh) 复合胶结充填材料及其制备方法和应用
US4329179A (en) Method for encapsulating arsenic-contaminated wastes
Dhanalaxmi et al. Study on the properties of concrete incorporated with various mineral admixtures–limestone powder and marble powder
WO2004080911A1 (fr) Composition de remblai fluide, regulee, de faible resistance, contenant des compose de chelation du fer
US5275652A (en) Concrete additive comprising a multicomponent admixture containing silica fume, its method of manufacture and concrete produced therewith
CN115818990A (zh) 尾矿凝胶材料及其在尾矿处理中的应用
DE3420171A1 (de) Verfahren zur aufbereitung von pulvrigen, schlammigen oder geloesten materialien, insbesondere umweltgifte oder anderweit umweltschaedliche stoffe enthaltenden abfaellen
JPS59129738A (ja) 鉄分含有スラツジを粉鉱石の塊状化に使用する方法
NO151544B (no) Fremgangsmaate for aa forhindre korrosjon av armeringen i betong
CN1039638C (zh) 含硫渣的硅酸盐水泥及其制造方法
JP2001342461A (ja) 地盤改良材

Legal Events

Date Code Title Description
AK Designated states

Designated state(s): AU BR DK FI JP NO RO SU US

AL Designated countries for regional patents

Designated state(s): AT BE CH DE FR GB LU NL SE