DD205422A1 - METHOD FOR BURNING HYDROPHOBIC GIP BONDING AGENTS - Google Patents

Abstract

The invention relates to a process for firing hydrophobic gypsum binders in indirect heating furnaces. This invention enables a labor-saving and energy-efficient production of hydrophobic gypsum binders by a simple firing process as the starting material for the production of hydrophobic gypsum bodies. According to the invention, the object is achieved by using gypsum together with refractory material in the form of wax or similar products in indirect heating combustion processes, e.g. in the gypsum boiler, is burned, during the firing process this melts and by an intensive mixing of the combustible finest distribution of the molten material and after further treatment of the fuel in a known manner, a hydrophobic gypsum binder is formed.

Description

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Process for firing hydrophobic gypsum binders

Application of the invention

The invention relates to a method for firing hydrophobic gypsum binders in kilns with indirect heating as a starting material for hydrophobic gypsum.

Characteristic of the known technical state

The hydrophobization of the building material plaster is the subject of many publications and patents. The previously known solutions can generally be divided into 2 groups:

1. Preparation of a hydrophobic gypsum binder, which results in a more or less water-repellent gypsum body after processing by other water repellents.

2. Use of non-hydrophobic gypsum binder, the addition of hydrophobic additives such as silicones, paraffin wax emulsions, ceresins, resin emulsions, fusible hard waxes and hard wax combinations with solid hydrocarbons and thereby after hydration by natural drying or by artificial drying (higher temperatures) hydrophobic plaster body is present.

Variant 2 has the disadvantage over variant 1 that in order to achieve the objective of producing a hydrophobic gypsum body, technologically higher expenditures are required by the required multiple components, in particular with regard to transport, stockpiling and metering

-7.JüR.1982 * Ol4o87

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and, moreover, due to inaccurate metering of the hydrophobizing agent, which is usually required in small quantities, quality drops may occur ",

The variant 1, however, has the disadvantage that the known methods for producing an already hydrophobic gypsum binder such

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• Double firing with an alaundose after the first firing

, Firing of hardening products of gypsum or Anhydritbijider in which hard wax or hard wax-like combinations are bound in a distributed form with solid hydrocarbons according to WP "process for producing a gypsum with water-resistant properties", d. that in this process a double burning, in the 1 · phase a burning of the non-hydrophobic gypsum binder and in the 2, phase burning of the hydrophobic gypsum binder, and also between these two combustion processes, a high work and energy costs for the production and drying of the required for the 2nd burning Srhärtungsproduktes is required

are too energy-consuming and labor-intensive, thus become very expensive and can be usefully used only for special fields of application ·

Object of the invention

The aim of the invention is to produce hydrophobic gypsum binders as Einkpmponentenprodukte for the production of hydrophobic plasterboard and / or the production of high-quality hydrophobic putties in only one firing process with significantly lower energy and Arbeitszeitaüfwand per unit of volume,

Explanation of the essence of the invention

The object of the invention is to provide a process for the production of hydrophobic gypsum binders for the simple production of hydrophobic gypsum building bodies and / or putty masks.

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According to the invention, the object is achieved by using gypsum together with meltable material in the form of waxes such as hard wax, bitumen or hard wax-containing combinations with solid hydrocarbons or wax-like materials how paraffin and stearin is burned in combustion processes with indirect heating, eg in the gypsum boiler, during the firing process melts the aüfschmelzbare material and by intensive mixing of the firing finest distribution of the molten material is formed by the melting of the wax or wax-like product and Due to the intensive mixing process, a physical attachment to the crystals of the gypsum stone occurs Depending on the type of material, it can also lead to a chemical saponification reaction between the molten material and the gypsum brick He adds reinforcing the hydrophobing effect, come.

The kiln is after the combustion process in a known manner, ζ. Βΐ by grinding processes, further processed. Depending on the desired hydrophobic effect, the burned-on hydrophobic binder can be used in this calcined form or can be deliberately made hydrophobic by mixing with nonhydrophobic binder and / or fillers and processed in the modified form.

The firing process must be carried out gently so as not to burn the fusible material component. The method is particularly suitable for the burning of hydrophobic hemihydrate in the temperature range of 100 ... 180 ⁰ C. To achieve a maximum hydrophobing effect, preferably fusible materials are to be used, which in addition to a physical attachment to the gypsum crystals with these chemical saponification processes such Hard waxes in the form of montan wax, carnauba wax and combinations of these waxes with solid hydrocarbons.

It is technologically particularly favorable, the fusible material component in granulated form already with the gypsum, preferably with a diameter U 5 mm

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should be fired, added to the firing unit or mixed in the final stage of the firing process. Depending on the desired hydrophobing effect and type of material, the amount of infusible material to be added should be between 1 and 10%, based on the mass of the gypsum plaster. In addition to the fusible material other known additives such as setting regulators, water-retentive, liquefying and emulsifying additives to further modify the binder ü. ä. be added or admixed in various stages of preparation of the hydrophobic fuel. The erfindüngsgemäße method allows in comparison to the prior art, a labor and energieöko- 'nomic production of hydrophobic gypsum binder in linbrandverfahren, which can be further processed as Hinkomponentenprodukt to hydrophobic gypsum and / or in conjunction with further Modifizierungsmaterialieη high-quality hydrophobic surfacer. With these products, new fields of application, in particular in the construction industry, for example in areas of wet lines or in the outdoor climate, can be economically developed.

Aüsführnnflsbeispiel

The invention will be explained in more detail below using an exemplary embodiment.

Cracked gypsum stone, grain diameter = 4 mm, is metered with 3 % granulated hard wax mixture of 50 % paraffin and 3D% montan wax in a gypsum cooker, fired under known technological conditions analogous to the model plaster production at 130 to 180 ⁰ C and after the firing process to a final fineness of = 1 % residue on the test sieve 200 μm ground ·

Gypsum bodies, produced from hydrophobic gypsum binders fired in the laboratory under similar conditions, have a reduced water uptake of * 60% compared with non-hydrophobic gypsum binder at comparable dry bulk density of the hardened product after 2 h of water exposure.

Claims (3)

1. A process for the preparation of hydrophobic gypsum binder characterized in that in gypsum combustion process with indirect heating, z, B. in the gypsum boiler, before or during the firing process of the gypsum meltable material in, form of waxes such as hard wax, bitumen or hard wax-containing combinations with solid hydrocarbons or Wachsähnlicheη materials such as paraffin and stearin is added, this melts during the firing process and by intensive mixing of the combustible finest distribution of the molten material, combined with a physical attachment and a dependent on the type of material possibly chemical saponification reaction with the crystals of the gypsum stone takes place and after further treatment of the fuel in a known manner, a hydrophobic gypsum binder is formed and this used depending on the desired hydrophobic effect or selectively hydrophobic with non-hydrophobic binders and / or fillers lt becomes. 2. The method according to item 1, characterized in that the firing process is carried out gently and preferably hemihydrate in the temperature range of 100 ... 180 ⁰ C is burned, 2.4 04 9 3 7 Patent claim 3 · A process according to pt. 1 and 2, characterized in that preferably fusible materials which undergo hydrolysis reactions with the gypsum crystals, such as hard waxes are used in> form of montan wax, Carnaübawachs and combinations of these waxes with solid hydrocarbons. 240493 7 A method according to point _e 1 to 3 characterized in that the fusible materials are preferably used in granular form. A method according Pkt _e 1 to 4, characterized in that the addition amount of fusible material is preferably 1 to 10%, based on the mass of the gypsum brick. Method according to Fkt _e 1 to 5, characterized in that the gypsum brick with a diameter of = 5 mm is fired. Method according to paragraph ¹ to 6 CUiU- ¹ FQh characterized in that other known additives for modifying the properties of the gypsum binder are added in addition to the material to be greased.