CH534643A - Cement prodn - with addn of cpds insolubilising or reducing dermatitis-causing hexavalent chromium salts - Google Patents
Cement prodn - with addn of cpds insolubilising or reducing dermatitis-causing hexavalent chromium saltsInfo
- Publication number
- CH534643A CH534643A CH223471A CH223471A CH534643A CH 534643 A CH534643 A CH 534643A CH 223471 A CH223471 A CH 223471A CH 223471 A CH223471 A CH 223471A CH 534643 A CH534643 A CH 534643A
- Authority
- CH
- Switzerland
- Prior art keywords
- cement
- chromates
- salts
- soluble
- hexavalent
- Prior art date
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
- C04B7/00—Hydraulic cements
- C04B7/36—Manufacture of hydraulic cements in general
- C04B7/38—Preparing or treating the raw materials individually or as batches, e.g. mixing with fuel
- C04B7/42—Active ingredients added before, or during, the burning process
-
- 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
- C04B22/085—Acids or salts thereof containing nitrogen in the anion, e.g. nitrites
-
- 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
- C04B22/12—Acids or salts thereof containing halogen in the anion
-
- 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
- C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
- C04B24/04—Carboxylic acids; Salts, anhydrides or esters thereof
Abstract
Cement is admixed during mfre. with a prod. capable of converting Cr6+ salts present, known to cause dermatitis, to harmless Cr salts. Pref. prod. may be a salt, pptg. the salts to insoluble chromates, e.g. BaCl2, Pb(NO3)2, Pb(CH2COO)2, or a salt reducing the salts to Cr3+ salts, e.g. KI, and is used in 2-5 times the stoichiometric amt. required, to cause pptn. or reduction. Pref. percentage quantities and product added are: 0.03 Pb(NO3)2, 0.025 Pb(CH3COO)2, 4 BaCl2, 0.02 Ki, 0.05 Na2S, 0.05 (NH4)2S, 0.1 FeSO4, 0.02 Na2SO3, 0.02 Na2S2O3, 0.02 NaHSO3.
Description
L'objet de la présente invention est un procédé de fabrication l'un ciment, tel qu'un ciment portland artificiel par exemple.
On sait que les ciments actuels produisent un eczéma qui est la lermatose professionnelle des ouvriers du bâtiment et des travaux publics.
En 1949, on découvrit que, dans la majorité des cas, cet eczéna était en réalité causé par une sensibilisation aux chromates soables présents à l'état de traces dans les ciments.
Pendant la cuisson de la farine obtenue par mélange de calaire et d'argile, une partie du chrome trivalent apportée par les natières premières silico-alumineuses (laitier, argile, parfois les friquets du four) se transforme en chromate hexavalent qui est soable dans l'eau et la cause des dermatoses citées.
Le but du procédé, objet de la présente invention, est d'obvier
cet inconvénient, et d'obtenir un ciment ne causant pas de dernatose.
Ce procédé est caractérisé par le fait que l'on mélange à un cinent, en cours de fabrication, un produit destiné à transformer, ar réduction ou insolubilisation, les sels de chrome hexavalents, ause de dermite, que contient ce ciment, en sels de chrome inof pensifs.
Le second objet de l'invention est un ciment obtenu selon ce rocédé.
Dans le procédé selon l'invention, on mélange au ciment, en ours de fabrication, un produit destiné à transformer, par insolu irisation ou réduction, ces sels de chrome hexavalents solubles en els insolubles.
Selon ce procédé, on opère par exemple, par insolubilisation, es chromates solubles en chromates insolubles. Pour ce faire, on ope le ciment avec un sel de baryum (BaCI2) ou de plomb Pb(N03)2 ou Pb(CH3COO)2 par exemple. Les chromates hexava vents solubles précipitent sous forme insoluble qui reste dans le ci nuent.
On peut aussi opérer par réduction des chromates hexavalents n chromates trivalents en dopant le ciment avec des sels réducours tels que l'iodure de potassium, le sulfure de sodium, le sulare d'ammonium, le sulfate ferreux, le sulfite de sodium, le thioulfate de sodium et le sulfite acide de sodium.
Le mélange ou dopage, peut se faire économiquement et failement à l'échelle industrielle.
La quantité à mélanger peut être introduite en cours de fabriation par une balance doseuse soit dans le clinker, soit dans le moulin broyeur, soit dans le gypse.
Les quantités recommandées des produits de dopage pour un iment portland contenant 40 milligrammes de chromate hexava monts par kilo de ciment sont les suivantes:
Produit de dopage % dans le ciment
Pb(N03)2 0,03
Pb(CH3COO)2 0,025
BaCI2 4
KI 0,02
Na2S 0,05
(NH4)2S 0,05
FeSO4 0.1
Na 2SO3 0.02
Na2S2O3 0,02
NaHSO3 0,02
Les quantités sont comprises en général entre 2 et 5 fois les quantités stoechiométriques nécessaires pour précipiter ou réduire les chromates contenues dans le ciment.
Lors de la préparation d'un mortier, le ciment entre en contact avec de l'eau, et les chromates solubles sont extraits dans la phase aqueuse. Si le ciment a été préalablement dopé avec un sel de baryum ou de plomb. les chromates précipitent sous forme insoluble et restent dans la masse du ciment. De même, si le ciment a été dopé avec un réducteur (sulfite de sodium ou sulfate de fer par exemple), quand le ciment entre en contact avec la peau les chromates sont transformés en chrome III. On peut ainsi empêcher la pénétration du chrome actif à travers la peau et éviter la sensibili sation. Des tests épicutanés d'un ciment dopé donnent dans le 90% des cas des réactions négatives (pas d'irritation de la peau) comparés au ciment non traité.
REVENDICATION I
Procédé de fabrication d'un ciment, caractérisé par le fait que l'on mélange à un ciment, en cours de fabrication, un produit destiné à transformer. par réduction ou insolubilisation, les sels de chrome hexavalents, cause de dermite. que contient ce ciment, en sels de chrome inoffensifs.
SOUS-REVENDICATIONS
1. Procédé selon la revendication, caractérisé par le fait que ledit produit est un sel précipitant lesdits sels hexavalents en chromates insolubles.
2. Procédé selon la revendication. caractérisé par le fait que ledit produit est un sel réduisant les sels de chrome hexavalents en sels de chrome trivalents.
3. Procédé selon la revendication et l'une des sous-revendications 1 ou 2, caractérisé par le fait que la quantité desdits produits est comprise entre 2 et 5 fois les quantités stoechiométriques nécessaires.
4. Procédé selon la revendication et la sous-revendication 3, caractérisé par le fait que les produits et les quantités sont les suivantes:
Produit de dopage % dans le ciment
Pb(NO3)2 0,03
Pb(ClI3COO)2 0,025
BaCI2 4
KI 0.02
Na2S 0,05
(NH4)2S 0.05
FeSO4 0,1
Na2SO3 0,02
Nua25203 0.02
NaHSO3 0.02
REVENDICATION Il
Ciment obtenu selon le procédé de la revendication I.
**ATTENTION** fin du champ DESC peut contenir debut de CLMS **.
The object of the present invention is a method of manufacturing a cement, such as an artificial Portland cement for example.
It is known that current cements produce eczema which is the occupational lermatosis of construction and public works workers.
In 1949, it was discovered that, in the majority of cases, this eczena was actually caused by sensitization to the soluble chromates present in traces in the cements.
During the baking of the flour obtained by mixing lime and clay, part of the trivalent chromium provided by the silico-aluminous raw materials (slag, clay, sometimes the beans of the oven) is transformed into hexavalent chromate which is soluble in the water and the cause of the dermatoses cited.
The aim of the method, object of the present invention, is to obviate
this drawback, and to obtain a cement which does not cause tardatosis.
This process is characterized by the fact that one mixes with a cinent, during manufacture, a product intended to transform, ar reduction or insolubilization, the hexavalent chromium salts, ause of dermatitis, which this cement contains, into salts of chrome inof thoughtful.
The second object of the invention is a cement obtained according to this method.
In the process according to the invention, a product intended to transform, by insolu irisation or reduction, these soluble hexavalent chromium salts into insoluble els is mixed with the cement in the process.
According to this process, for example, by insolubilization, the chromates which are soluble in insoluble chromates are operated. To do this, the cement is ope with a barium (BaCl2) or lead salt Pb (N03) 2 or Pb (CH3COO) 2 for example. The soluble hexava-vent chromates precipitate in insoluble form which remains in the cloud.
One can also operate by reduction of the hexavalent chromates n trivalent chromates by doping the cement with reducing salts such as potassium iodide, sodium sulphide, ammonium sulare, ferrous sulphate, sodium sulphite, thioulfate sodium and sodium acid sulfite.
The mixing or doping, can be done economically and failably on an industrial scale.
The quantity to be mixed can be introduced during manufacture by a metering scale either in the clinker, or in the mill mill, or in the gypsum.
The recommended amounts of doping agents for an iment portland containing 40 milligrams of mounted hexava chromate per kilogram of cement are as follows:
Doping product% in cement
Pb (N03) 2 0.03
Pb (CH3COO) 2 0.025
BaCI2 4
KI 0.02
Na2S 0.05
(NH4) 2S 0.05
FeSO4 0.1
Na 2SO3 0.02
Na2S2O3 0.02
NaHSO3 0.02
The amounts are generally between 2 and 5 times the stoichiometric amounts necessary to precipitate or reduce the chromates contained in the cement.
When preparing a mortar, the cement comes into contact with water, and the soluble chromates are extracted into the aqueous phase. If the cement has been previously doped with a barium or lead salt. the chromates precipitate in insoluble form and remain in the mass of the cement. Likewise, if the cement has been doped with a reducing agent (sodium sulphite or iron sulphate for example), when the cement comes into contact with the skin, the chromates are transformed into chromium III. This can prevent the penetration of active chromium through the skin and prevent sensitization. Patch tests of a doped cement give in 90% of cases negative reactions (no skin irritation) compared to untreated cement.
CLAIM I
Process for manufacturing a cement, characterized by the fact that a product intended to transform is mixed with a cement during manufacture. by reduction or insolubilization, hexavalent chromium salts, cause of dermatitis. contained in this cement, in harmless chromium salts.
SUB-CLAIMS
1. Method according to claim, characterized in that said product is a salt precipitating said hexavalent salts in insoluble chromates.
2. Method according to claim. characterized in that the said product is a salt which reduces hexavalent chromium salts to trivalent chromium salts.
3. Method according to claim and one of sub-claims 1 or 2, characterized in that the quantity of said products is between 2 and 5 times the stoichiometric quantities required.
4. Method according to claim and sub-claim 3, characterized in that the products and the quantities are as follows:
Doping product% in cement
Pb (NO3) 2 0.03
Pb (ClI3COO) 2 0.025
BaCI2 4
KI 0.02
Na2S 0.05
(NH4) 2S 0.05
FeSO4 0.1
Na2SO3 0.02
Nua25203 0.02
NaHSO3 0.02
CLAIM It
Cement obtained according to the process of claim I.
** ATTENTION ** end of DESC field can contain start of CLMS **.
Claims (1)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CH223471A CH534643A (en) | 1971-02-16 | 1971-02-16 | Cement prodn - with addn of cpds insolubilising or reducing dermatitis-causing hexavalent chromium salts |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CH223471A CH534643A (en) | 1971-02-16 | 1971-02-16 | Cement prodn - with addn of cpds insolubilising or reducing dermatitis-causing hexavalent chromium salts |
Publications (1)
Publication Number | Publication Date |
---|---|
CH534643A true CH534643A (en) | 1973-03-15 |
Family
ID=4228992
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CH223471A CH534643A (en) | 1971-02-16 | 1971-02-16 | Cement prodn - with addn of cpds insolubilising or reducing dermatitis-causing hexavalent chromium salts |
Country Status (1)
Country | Link |
---|---|
CH (1) | CH534643A (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2390394A1 (en) * | 1977-05-12 | 1978-12-08 | Hoechst Ag | Preventing discoloration of plaster joints or coatings - using a reducing agent either as additive or as a paint |
EP0054314A1 (en) * | 1980-12-17 | 1982-06-23 | Aktieselskabet Aalborg Portland-Cement-Fabrik | A method and a plant for producing a dry cement composition |
EP0697380A2 (en) * | 1994-08-19 | 1996-02-21 | ITALCEMENTI S.p.A. | Chromate free cements and a process for preparing them |
WO1998022407A1 (en) * | 1996-11-15 | 1998-05-28 | Holderchem Holding Ag | Method for producing cement |
WO1999037593A1 (en) * | 1998-01-27 | 1999-07-29 | Chemische Werke Zell-Wildshausen Gmbh | Medium for reducing chromium (vi) ions in a water-curing mass |
US7128782B2 (en) | 2003-11-21 | 2006-10-31 | W.R. Grace & Co.-Conn. | Sulfate dispersion chromate reducer |
-
1971
- 1971-02-16 CH CH223471A patent/CH534643A/en not_active IP Right Cessation
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2390394A1 (en) * | 1977-05-12 | 1978-12-08 | Hoechst Ag | Preventing discoloration of plaster joints or coatings - using a reducing agent either as additive or as a paint |
EP0054314A1 (en) * | 1980-12-17 | 1982-06-23 | Aktieselskabet Aalborg Portland-Cement-Fabrik | A method and a plant for producing a dry cement composition |
EP0160746A1 (en) * | 1980-12-17 | 1985-11-13 | Aktieselskabet Aalborg Portland-Cement-Fabrik | A dry cement composition |
EP0160747A1 (en) * | 1980-12-17 | 1985-11-13 | Aktieselskabet Aalborg Portland-Cement-Fabrik | A dry cement composition and a method for producing the same |
US4572739A (en) * | 1980-12-17 | 1986-02-25 | Rasmussen Poul L | Method for reducing chromate dermatitis |
US4784691A (en) * | 1980-12-17 | 1988-11-15 | Aktieselskabet Aalborg Portland - Cement - Fabrik | Dry cement composition |
EP0697380A2 (en) * | 1994-08-19 | 1996-02-21 | ITALCEMENTI S.p.A. | Chromate free cements and a process for preparing them |
EP0697380A3 (en) * | 1994-08-19 | 1997-05-02 | Italcementi Spa | Chromate free cements and a process for preparing them |
WO1998022407A1 (en) * | 1996-11-15 | 1998-05-28 | Holderchem Holding Ag | Method for producing cement |
WO1999037593A1 (en) * | 1998-01-27 | 1999-07-29 | Chemische Werke Zell-Wildshausen Gmbh | Medium for reducing chromium (vi) ions in a water-curing mass |
US7128782B2 (en) | 2003-11-21 | 2006-10-31 | W.R. Grace & Co.-Conn. | Sulfate dispersion chromate reducer |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PL | Patent ceased |