Abstract:
Die Erfindung betrifft ein Verfahren zur Herstellung von Hartgips aus gebranntem Beta-Hemihydratgips, umfassend Zuführen von Gipsmaterial, das überwiegend aus Beta- Hemihydratgips besteht, zu einem Nachreaktor (3), Nachbehandeln im Nachreaktor (3) zur Bildung von Hartgips, wobei der Beta-Hemihydratgips direkt zu Alpha-Hemihydratgips bei einer Temperatur oberhalb der Kalziniertemperatur von 95 °C umgewandelt wird, Ausbringen des Hartgipses aus dem Nachreaktor (3) und Kühlen. Es erfolgt ein Einstellen der Temperatur beim Zuführen des Gipsmaterials zum Nachreaktor (3) auf mindestens die Kalziniertemperatur, Umwandeln in dem Nachreaktor (3) mit einer Verweilzeit von weniger als 30 Minuten unter Zuführung von Wasserdampf von extern und Regeln der Temperatur sowie des Drucks im Nachreaktor (3) derart, dass die Temperatur mindestens 95 °C beträgt und ein Überdruck herrscht.
Abstract:
A method for continuously forming gypsum-based panels of high fixing strength comprises the steps of: • forming a mixture comprising stucco, non-pregelatinized migratory starch, glass fibre, fluidizer and water; • casting the mixture in a continuous band; • maintaining the band under conditions sufficient for the stucco to form an interlocking matrix of set gypsum; • cutting the band to form one or more wet panel precursors; and • drying the wet panel precursor to form one or more gypsum-based panels. • The weight ratio of water to stucco in the mixture is less than 0.7; • the stucco is present in the mixture in an amount of over 60 wt% relative to the total solids content of the mixture; • the starch is present in the mixture in an amount of over 3 wt% relative to the the stucco; • the glass fibre is present in the mixture in an amount of over 1 wt% relative to the stucco; • the fluidizer is is present in the mixture in an amount of at least 0,1 wt% relative to the stucco; and the density of the gypsum-based panel is greater than 700 kg/m.
Abstract:
The present invention is an apparatus and process for cooling and de-steaming hot calcined stucco used in the production of gypsum boards or bagged plaster. The apparatus is a fluid bed stucco cooler and comprises a cooler housing having a plenum having a stucco inlet and stucco outlet. The stucco cooler includes a rotating disk in the plenum. The rotating disk includes nozzle for spraying fluid, and is attached to a rotable shaft extending from the side of the cooler also includes a fluidization pad and agitator to help to mix the air and the stucco powder to insure fluidization, prevent channeling, and prevent the stucco powder from building up on the various components. The air also forces steam from the hot calcined stucco out through an air outlet located at the top of the stucco cooler, thereby de-steaming the stucco. The stucco flows through the plenum and passes over the cooling coils, thereby cooling the stucco as it reaches the stucco outlet.
Abstract:
Disclosed are various methods for reducing levels of elemental sulfur within gypsum products such as wall board. Gypsum sometimes includes increased levels of elemental sulfur. Such sulfur can be corrosive and otherwise harmful at elevated levels. The disclosure contemplates reacting the elemental sulfur with copper to copper sulfide. This reaction has the benefit of reducing the levels of elemental sulfur present within the final gypsum product. The copper can be added at any of a variety of locations in the manufacturing process. This is a very efficient method for reducing elemental sulfur in the production of gypsum products.
Abstract:
The instant invention is concerned with the post-treatment of β-hemihydrate plasters for the purpose of stabilization. The invention relies in the addition of a retardant to the calcined β-hemihydrate. It is also the purpose of the invention to provide stabilized β-hemihydrate plasters which exhibit advantageous properties.
Abstract:
A method for preparing a modified beta-stucco from calcined natural rock gypsum that includes preparing a solution of liquid diethylene-triamine-pentaacetic acid in water, applying the solution onto beta-stucco while hot from the calciner, forming a wetted beta-stucco, and allowing the wetted stucco to dry and heal, forming the modified beta-stucco.
Abstract:
In einem Verfahren zur kontinuierlichen Konditionierung von Stuckgips wird dieser in Form von Partikeln aus einer vorgeschalteten Kalzinieranlage einem Stuckgipskühler zugeführt. In dem Stuckgipskühler werden zunächst lösliches Caiciumsulfat-Anhydrit zu Calciumsulfat-Halbhydrat und Calciumsulfat-Dihydrat zu Calciumsulfat-Halbhydrat umgewandelt und Kristalldefekte geheilt. Anschließend wird der Stuckgips mit Umgebungsluft in Kontakt gebracht und durch diese entfeuchtet und hierbei gleichzeitig indirekt gekühlt.
Abstract:
The present invention is an apparatus and process for cooling and de-steaming hot calcined stucco used in the production of gypsum boards or bagged plaster. The apparatus is a fluid bed stucco cooler and comprises a cooler housing having a plenum having a stucco inlet and stucco outlet. The stucco cooler includes a rotating disk in the plenum. The rotating disk includes nozzle for spraying fluid, and is attached to a rotable shaft extending from the side of the cooler also includes a fluidization pad and agitator to help to mix the air and the stucco powder to insure fluidization, prevent channeling, and prevent the stucco powder from building up on the various components. The air also forces steam from the hot calcined stucco out through an air outlet located at the top of the stucco cooler, thereby de-steaming the stucco. The stucco flows through the plenum and passes over the cooling coils, thereby cooling the stucco as it reaches the stucco outlet.
Abstract:
The invention relates to a method for stabilising a metastable soluble anhydrite III, to a method for producing a hydraulic binder based thereon, to the thus obtainable hydraulic binder, to a method for the use thereof in the cement industry and to an industrial plant for carrying out the inventive method. The method consists in stabilising a metastable soluble anhydrite III by mechanically stressing the particles thereof in such a way the crystal structure of the particles is modified and the metastable phase thereof is stabilised. Said invention makes it possible to stabilise the metastable soluble anhydrite III particles without using current steps for heating and quenching said particles.
Abstract:
A method of conditioning stucco comprises the steps of supplying a quantity of stucco particles to a reaction vessel, the stucco particles comprising calcium sulphate hemihydrate and/or calcium sulphate anhydrite, as well as calcium sulphate dihydrate; and conditioning the stucco particles at a temperature of at least 100°C and a humidity of at least 70%. During the step of conditioning the stucco particles, the bulk density of the stucco particles within the reaction vessel is at least 1 g/cm 3 .