FR2510548A1 - PLASTER PREPARATION PROCESS - Google Patents
PLASTER PREPARATION PROCESS Download PDFInfo
- Publication number
- FR2510548A1 FR2510548A1 FR8213020A FR8213020A FR2510548A1 FR 2510548 A1 FR2510548 A1 FR 2510548A1 FR 8213020 A FR8213020 A FR 8213020A FR 8213020 A FR8213020 A FR 8213020A FR 2510548 A1 FR2510548 A1 FR 2510548A1
- Authority
- FR
- France
- Prior art keywords
- plaster
- calcination
- cake
- alpha
- laminated
- 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.)
- Withdrawn
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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
- C04B11/26—Calcium sulfate cements strating from chemical gypsum; starting from phosphogypsum or from waste, e.g. purification products of smoke
- C04B11/262—Calcium sulfate cements strating from chemical gypsum; starting from phosphogypsum or from waste, e.g. purification products of smoke waste gypsum other than phosphogypsum
- C04B11/264—Gypsum from the desulfurisation of flue gases
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
- Materials For Medical Uses (AREA)
- Thermotherapy And Cooling Therapy Devices (AREA)
Abstract
Description
L'invention se rapporte à un procédé de prépara- tion de plâtre à partir des boues produites par les instal lations de désulfuration de gaz de fumée, dans lequel les boues de désulfuration sont soumises à une calcination vers 900C ou plus et sont transformées en plâtre alpha. The invention relates to a process for the preparation of plaster from sludge produced by flue gas desulphurization plants, in which the desulphurisation sludge is calcined at around 900C or more and is transformed into plaster alpha.
On sait que l'expression 11plâtre alpha1, désigne un semi-hydrate qui fait prise en un matériau de particulière dureté et, de ce fait, est utilisé préférentiellement dans l'industrie du bâtiment. Il va de soi que de l'acide sulfuri- que doit être présent lors de la calcination. Celui-ci peut être ajouté aux boues de désulfuration avant ou pendant le traitement thermique lié à la calcination. We know that the expression 11 alpha1 plaster, designates a semi-hydrate which sets in a material of particular hardness and, therefore, is used preferentially in the building industry. It goes without saying that sulfuric acid must be present during the calcination. This can be added to the desulphurisation sludge before or during the heat treatment linked to calcination.
Dans le cadre des dispositions connues (par la pratique) , le traitement de calcination sieffectue dans un réacteur avec chauffage d'enveloppe et agitation Le plâtre alpha obtenu n'offre pas de manière reproductlble la qualité exigée, c'est-à-dire la dureté élevée exigée après prise En pratique, la qualité du plâtre alpha dépend de plusieurs pa ramètresS principalement de la concentrati3n en acide 5 de la température, du temps de contact et de la proportion plâtre/ acide.Si 1 on considère les volumes élémentaires individuels dans le réacteur ou a lieu la calcination suivant les disposiu tions connues, il n'est pas sur que dans tous ceu,-ci existent les mêmes valeurs des paramètres régissant la réaction et par suite les mêmes conditions de réaction. Il en résulte un plâtre alpha de qualité variable et souvent insuffisante
L'invention a pour but diamenager le procédé du genre considéré de manière à permettre la fabrication de plâtre alpha offrant une constante qualité (au sens des explications ci-dessus) et conduisant par suite à une grande dureté après prise.In the context of known arrangements (in practice), the calcination treatment takes place in a reactor with heating of the shell and stirring. The alpha plaster obtained does not reproducibly offer the required quality, that is to say the high hardness required after setting In practice, the quality of alpha plaster depends on several parameters, mainly on the acid concentration 5 of the temperature, the contact time and the plaster / acid proportion. If we consider the individual elementary volumes in the reactor where calcination takes place according to the known arrangements, it is not certain that in all these, the same values of the parameters governing the reaction exist and consequently the same reaction conditions. This results in alpha plaster of variable quality and often insufficient
The object of the invention is to make the process of the type considered diamenable so as to allow the manufacture of alpha plaster offering a constant quality (within the meaning of the explanations above) and consequently leading to great hardness after setting.
Ce but est atteint selon l'invention par le fait que les boues de désulfuration sont appliquées sous forme de gâteau stratifié sur un support perméable à la vapeur et sont calcinées en presence d'acide sulfurique et/ou/vapeur dans le gâteau stratifié. Dans le cadre de l'invention, 17acide sulfurique peut ainsi ct-ce apporté,- à température convenable au gâteau stratifié que constituent les boues de désulfuration mais il existe aussi la possibilité de mélanger préalablement l'acide sulfurique aux boues de désulfuration et seulement après de former le gâteau stratifié. Dans ce cas, seul a encore lieu pour la calcination l'apport de vapeur, qui assure l'échauffement à la température nécessaire pour la calcination. This object is achieved according to the invention by the fact that the desulphurization sludges are applied in the form of a laminated cake on a vapor-permeable support and are calcined in the presence of sulfuric acid and / or / vapor in the laminated cake. In the context of the invention, the sulfuric acid can thus be brought, at a suitable temperature to the laminated cake that the desulphurization sludge constitutes, but there is also the possibility of mixing sulfuric acid beforehand with the desulphurization sludge and only after to form the layered cake. In this case, only the addition of steam still takes place for calcination, which provides heating to the temperature necessary for calcination.
Dans le procédé selon l'invention, le gâteau stratifié est de préférence formé sur une bande de filtration sous vide connue en soi, sur laquelle a lieu la calcination de manière continue. Mais le gâteau stratifié peut aussi être formé dans le panier d'une centrifugeuse. C'est dans ce dernier qu'a alors lieu la calcination En règle générale, le gâteau stratifié sera, après traitement de calcination, lavé à l'eau et, seulement après cette opération, enlevé du support perméable à la vapeur ainsi qu'à l'eau pour l'opéra- tion de lavage. In the process according to the invention, the laminated cake is preferably formed on a vacuum filtration band known per se, on which calcination takes place continuously. But the laminated cake can also be formed in the basket of a centrifuge. It is in this latter that calcination then takes place. As a general rule, the laminated cake will, after calcination treatment, be washed with water and, only after this operation, removed from the vapor permeable support as well as water for the washing operation.
Lorsqu'on utilise une centrifugeuse, le traitement décrit s'effectue de manière discontinue. Lorsqu'on opère avec une bande de filtration sous vide, le procédé selon l'invention peut être aisément mené de façon continue. Dans ce cas, l'opération de lavage peut être effectuée de manière continue sur la bande filtration sous vide à la suite de la cal cination, de l'eau de lavage étant apportée sur le gâteau stratifié déjà calciné. La bande filtrante traverse ainsi d'abord une chambre ae calcination, puis une chambre de lavage. When using a centrifuge, the described treatment is carried out discontinuously. When operating with a vacuum filtration band, the process according to the invention can easily be carried out continuously. In this case, the washing operation can be carried out continuously on the vacuum filtration band following calcination, washing water being supplied to the already calcined laminated cake. The filter band thus first passes through a calcining chamber, then a washing chamber.
Les avantages obtenus consistent en ceci que le procédé selon l'invention permet de préparer du plâtre alpha offrant une qualité toujours égale et conduisant à une haute dureté après prise. Les paramètres régissant la réaction, tels que la concentration en acide, la température, le temps de contact, la proportion plâtre/acide, etc, peuvent être ajustés de manière très précise, tandis que l'épaisseur de couche peut être réglée sans difficulté dans toute installation con çue pour la mise en oeuvre du procédé selon 11 invention de telle manière que pratiquement dans chaque volume élémentaire du gâteau stratifié existent les memes valeurs de paramètres régissant la réaction.On peut donc obtenir un plâtre alpha de qualité constant. Le mélange plâtre alpha/acide sulfurique non lavé fait prise après malaxage avec du carbonate de cal c um et un peu d'eau. Après lavage à l'eau du gâteau stratifié contenant de l'acide sulfurique, on peut réaliser, aussi bien par gâchage avec un peu d'eau que par incorporation de craie et d'un peu d'eau, un plâtre capable de faire prise de qualité toujours gale.Le plâtre alpha le plus dur est obtenu dans le cadre de l'invention par traitement avec un acide sulfurique à 52 % en-srirol à des températures voisines du p@@nt d'ébullition, lequel se situe vers 105 C. Il convient de prévoir dans le gâteau stratifié une proportion plâtre/ acide de 1/4 et un temps de contact de 10 minutes. Le plâtre alpha humide perd rapidement sa faculte de prise après absorption d'eau aussi Lien à la température ordinaire qusà 700C. A 950, le plâtre alpha humide est solide tant qu'il renferme de l'humidité résiduelle. Puis il perd le reste de l'eau de cristallisation et se transforme en anhydrite. The advantages obtained consist in that the method according to the invention makes it possible to prepare alpha plaster offering an always equal quality and leading to a high hardness after setting. The parameters governing the reaction, such as the acid concentration, the temperature, the contact time, the plaster / acid ratio, etc., can be adjusted very precisely, while the layer thickness can be adjusted without difficulty in any installation designed for carrying out the process according to the invention in such a way that practically in each elementary volume of the laminated cake the same values of parameters governing the reaction exist. It is therefore possible to obtain an alpha plaster of constant quality. The alpha-plaster / unwashed sulfuric acid mixture is set after mixing with calcium carbonate and a little water. After washing the laminated cake containing sulfuric acid with water, a plaster capable of setting can be produced, both by mixing with a little water and by incorporating chalk and a little water. always scabby quality. The hardest alpha plaster is obtained in the context of the invention by treatment with a 52% sulfuric acid en-srirol at temperatures close to the boiling point, which is around 105 C. A plaster / acid ratio of 1/4 and a contact time of 10 minutes should be provided in the laminated cake. The wet alpha plaster quickly loses its setting ability after absorption of water. Also at ordinary temperature only at 700C. At 950, wet alpha plaster is solid as long as it contains residual moisture. Then it loses the rest of the water of crystallization and turns into anhydrite.
Claims (5)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE3129878A DE3129878C2 (en) | 1981-07-29 | 1981-07-29 | Process for the production of alpha calcium sulfate hemihydrate from desulfurization sludge |
Publications (1)
Publication Number | Publication Date |
---|---|
FR2510548A1 true FR2510548A1 (en) | 1983-02-04 |
Family
ID=6137979
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
FR8213020A Withdrawn FR2510548A1 (en) | 1981-07-29 | 1982-07-26 | PLASTER PREPARATION PROCESS |
Country Status (5)
Country | Link |
---|---|
JP (1) | JPS5832021A (en) |
DE (1) | DE3129878C2 (en) |
FR (1) | FR2510548A1 (en) |
IT (1) | IT1153125B (en) |
NL (1) | NL8203014A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0181088A1 (en) * | 1984-10-10 | 1986-05-14 | A/S Niro Atomizer | A process for the manufacture of a quick setting high strength hardening composition |
EP0237802A1 (en) * | 1986-02-20 | 1987-09-23 | Gebr. Knauf Westdeutsche Gipswerke KG | Process for the preparation of calcium sulphate anhydrite and curable calcium sulphates |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3240317C2 (en) * | 1982-10-30 | 1986-06-12 | Gottfried Bischoff Bau kompl. Gasreinigungs- und Wasserrückkühlanlagen GmbH & Co KG, 4300 Essen | Process for the production of calcium sulphate dihydrate in the course of the desulphurisation of flue gases from power plant boiler systems |
DE3245754C2 (en) * | 1982-12-10 | 1986-03-13 | Gottfried Bischoff Bau kompl. Gasreinigungs- und Wasserrückkühlanlagen GmbH & Co KG, 4300 Essen | Process for the production of calcium sulfate dihydrate |
DE3414822A1 (en) * | 1984-04-19 | 1985-11-07 | Gottfried Bischoff Bau kompl. Gasreinigungs- und Wasserrückkühlanlagen GmbH & Co KG, 4300 Essen | METHOD FOR THE PROCESSING OF DESULFURATION SLUDGE OF A FLUE GAS DESULFURATION PLANT |
FR2594363B1 (en) * | 1986-02-19 | 1988-06-17 | Kuhn Sa | FOUNDRY CORE SORTING MACHINE |
DE4409219C2 (en) * | 1994-03-18 | 1997-03-27 | Salzgitter Anlagenbau | Process for the continuous production of alpha calcium sulfate hemihydrate from calcium sulfate dihydrate |
DE10050072B4 (en) * | 2000-10-10 | 2011-07-07 | BOKELA Ingenieurgesellschaft für mechanische Verfahrenstechnik mbH, 76131 | Process for the chemical and / or thermal conversion of at least one substance and device for carrying out the process |
CN107417148A (en) * | 2017-09-04 | 2017-12-01 | 青川县天运金属开发有限公司 | In a kind of electroplating sludge after METAL EXTRACTION tailings processing method |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CH282976A (en) * | 1949-03-26 | 1952-05-31 | Petra Corp Reg Trust | Method for producing plaster of paris in flowing, superheated steam and device for carrying out the method. |
FR1409248A (en) * | 1963-07-04 | 1965-08-27 | Prayon | Process for the purification of residual gypsum from the manufacture of phosphoric acid by sulfuric attack of natural phosphates |
FR2153928A5 (en) * | 1971-09-18 | 1973-05-04 | Knauf Westdeutsche Gips | Bondable calcium sulphate - by roasting calcium sulphite pieces,immersing in water,roasting again and grinding |
JPS5043096A (en) * | 1973-08-20 | 1975-04-18 | ||
DE2659860A1 (en) * | 1975-03-31 | 1977-09-01 | Hyogo Prefectural Government | PROCESS FOR THE PRODUCTION OF PLASTER IN THE FORM OF NEEDLE-SHAPED ANHYDRITE II |
DE2925468A1 (en) * | 1979-06-23 | 1981-01-08 | Bischoff Gasreinigung | Gypsum mfg. plant using sulphur di:oxide in waste gas - where washing tower uses helical jets of liq. to produce very small gypsum crystals removed in centrifuge and then calcined |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1101771A (en) * | 1963-08-14 | 1968-01-31 | Bpb Industries Ltd | Improvements relating to the production of gypsum plaster |
DE2519489A1 (en) * | 1975-05-02 | 1976-11-18 | Heinz Hoelter | Gas purification to remote sulphur dioxide - with calcium cpds in presence of sulphuric and other acids to prevent deposition of calcium carbonate |
DE2730707A1 (en) * | 1977-07-07 | 1979-01-25 | Kloeckner Humboldt Deutz Ag | Recovery of gypsum from sludges from desulphurising plants - for use as raw material in cement mfr. to control setting of cement |
-
1981
- 1981-07-29 DE DE3129878A patent/DE3129878C2/en not_active Expired
-
1982
- 1982-07-26 FR FR8213020A patent/FR2510548A1/en not_active Withdrawn
- 1982-07-28 NL NL8203014A patent/NL8203014A/en not_active Application Discontinuation
- 1982-07-28 JP JP57130536A patent/JPS5832021A/en active Pending
- 1982-07-29 IT IT22642/82A patent/IT1153125B/en active
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CH282976A (en) * | 1949-03-26 | 1952-05-31 | Petra Corp Reg Trust | Method for producing plaster of paris in flowing, superheated steam and device for carrying out the method. |
FR1409248A (en) * | 1963-07-04 | 1965-08-27 | Prayon | Process for the purification of residual gypsum from the manufacture of phosphoric acid by sulfuric attack of natural phosphates |
FR2153928A5 (en) * | 1971-09-18 | 1973-05-04 | Knauf Westdeutsche Gips | Bondable calcium sulphate - by roasting calcium sulphite pieces,immersing in water,roasting again and grinding |
JPS5043096A (en) * | 1973-08-20 | 1975-04-18 | ||
DE2659860A1 (en) * | 1975-03-31 | 1977-09-01 | Hyogo Prefectural Government | PROCESS FOR THE PRODUCTION OF PLASTER IN THE FORM OF NEEDLE-SHAPED ANHYDRITE II |
DE2925468A1 (en) * | 1979-06-23 | 1981-01-08 | Bischoff Gasreinigung | Gypsum mfg. plant using sulphur di:oxide in waste gas - where washing tower uses helical jets of liq. to produce very small gypsum crystals removed in centrifuge and then calcined |
Non-Patent Citations (2)
Title |
---|
BULLETIN DE LA SOCIETE CHIMIQUE DE FRANCE, no. 10, 1970, pages 3377-3382; J.-J. GARDET et al.: "Etude des formes hydratées du sulfate de calcium" * |
CHEMICAL ABSTRACTS, vol. 83, no. 12, 22 septembre 1975, page 321, no. 102522c, Columbus, Ohio, US; & JP - A - 75 43 096 (NIHON CEMENT CO., LTD.) 18-04-1975 * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0181088A1 (en) * | 1984-10-10 | 1986-05-14 | A/S Niro Atomizer | A process for the manufacture of a quick setting high strength hardening composition |
EP0237802A1 (en) * | 1986-02-20 | 1987-09-23 | Gebr. Knauf Westdeutsche Gipswerke KG | Process for the preparation of calcium sulphate anhydrite and curable calcium sulphates |
Also Published As
Publication number | Publication date |
---|---|
IT8222642A0 (en) | 1982-07-29 |
JPS5832021A (en) | 1983-02-24 |
IT1153125B (en) | 1987-01-14 |
DE3129878C2 (en) | 1985-01-31 |
IT8222642A1 (en) | 1984-01-29 |
NL8203014A (en) | 1983-02-16 |
DE3129878A1 (en) | 1983-03-10 |
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ST | Notification of lapse |