DE2022419A1 - Porous granules and shaped articles from mineral powders - Google Patents

Abstract

Porous granules or shaped articles are produced from mineral powders, such as clay or combustion duct, by (a) mixing the powder with water to form a deformable paste, (b) adding a foam mass to the paste, and (c) hardening the mixture by baking or adding a hydraulic binder. The density and strength of the porous granules or articles can be controlled accurately. The granules become consolidated during baking, so that better one can be made of a rotating furnace during baking. Articles such as tiles can be produced cheaply. The viscosity of the paste is pref. lowered by adding a liquefying agent, e.g. an electrolyte, pref. sodium carbonate or sodium silicate.

Description

2'Process for the production of expanded, fired granules or Shaped bodies made of powdery mineral substances, in particular rock flour, e.g. clay dust. "The invention relates to a process for the production of distended Fired granules or shaped bodies made of dusty mineral substances, in particular rock flour, such as clay dust, with the powdery mineral Substances can be mixed with water to form a pulpy, malleable liquid.

It has already been proposed to use the powdery mineral substances to mix in such liquid additives as a result of a chemical reaction split off gases with each other, so that the mixture foams in the cold state, whereupon the mixture is fired.

The invention provides a method for producing granules and molded bodies from such cold-foaming wet, which is less expensive and in which additives are used that make the entire process more efficient.

According to the invention this is achieved in that after production a foam mass is added to the pulpy, malleable mass, whereupon the Gesaitwischem is burned.

The wet show consists of a foaming agent known per se, which foams when water is added. The addition of the show aces after manufacture the pulpy mass has the advantage that the amount of foaming agent added is lower can be.

The following can be used as Schawabildner: surfactants fatty alcohol polyglycol ether1 Fatty alcohol sulfate, alkyl sulfonates, fatty alcohol ether sulfate, alkylphenol polyglycol ether Etc.

They are in amounts of 0.1 up to 7.5 percent by weight, based on the amount of water added.

The amount of foam that is added to the pasty mass is approximately 10 to 50 percent by weight, based on the starting material, for example the Clay dust.

According to a further feature of the invention, the pulpy mass Liquefying agents added, which have the task of reducing the viscosity of the pulpy Reduce mass. If the viscosity of the pulpy mass is reduced, then the foam mass can be better mixed with the pulpy mass and finely distributed. An electrolyte is expediently used as a liquefying agent, e.g. soda, water glass, or humic acid.

The electrolyte is expediently added to the water used for production serves the pulpy mass. The amount of liquefying agent to be added is about 2 to 12 percent by weight. based on the amount of water to be added.

The pulpy mass and also the one from the pulpy mass and the foam mass existing overall mixture is subjected to a constant movement and that is how it is long until the total mixture is processed either into granules or into molded bodies that will be burned afterwards.

Maintaining constant movement has the advantage that the total mixes, including the pulpy mass in a relatively thin liquid state remains.

If the movement of the entire mixture is stopped, it solidifies the overall mixture as a result of the thixotropic properties of this mixture, so that the gas bubbles contained in it are fixed.

Should substances be used as starting materials that are listed under Exposure to heat, e.g. as a result of the drying process that initially occurs during firing tend to disintegrate, then a binder is added to the pasty mass. the Raw materials that are processed using this process are highly refractory Masses such as calcined clay, zircon, rutile, quartz and basalt dust and also Magnesite or aluminum oxide The binding agent used is, for example, sulphite waste liquor, dextrin or glue, i.e. those substances that still form the pulpy mass even when dry give cohesion.

The total mixture can after the addition of the foam mass after completion of the mixing process are filled into molds, which are then fired.

But it can also be the total mixture with the help of known devices, e.g. a perforated plate, a granulating plate or a granulating tube into granules processed, which are then also burned.

According to a further feature of the invention, the total mixture substances that remove water from the overall mixture are also added the overall mixture becomes stiffer and supports the thixotropic effect on termination the mixing process. Sawdust can be used as substances that remove water from the mixture are used with a grain size of about 1 mm.

Other fibrous organic substances are also suitable for this purpose. Farther For this purpose, sulphite waste liquor or cellulose can also be added to the mixture will. Inorganic substances also serve such a purpose, e.g.

Lime and bentonite, water glass and waste from mineral fiber production.

In the production of moldings from the total mixture, it is also possible proceed in such a way that the total mixture is introduced into molds that are equipped with an absorbent and combustible material are designed or made of consist of such material. This also removes water from the overall mixture, which penetrates into this absorbent material and thereby stiffens the mixture cares. This also ensures that the individual molded bodies in the subsequent Burning process does not stick together.

The subsequent firing process, either the granules or the off Moldings produced from the overall mixture lead to a compaction of the granules or the form body.

You have it in your hand by choosing the firing temperature to determine the degree of compaction beforehand.

Are the foamed granules e.g. at a temperature of 10700 when fired, a bulk weight of around 550 kg per cbm is obtained. Will however the foamed granules, fired at a temperature of 11,000, are then obtained a bulk weight of 650 kg per cubic meter.

The production of the foamed granules from a cold foamed Mass therefore has the advantage that it is possible to maintain the strength of the granulate to be determined exactly beforehand Another advantage of the V * rfaxwen according to the invention is that the degree of filling of a rotary kiln with such Seed mix is charged, can become larger because of the subsequent Firing process, the granules or the moldings are compacted.

This means that the rotary kiln is used better than with the usual pyroplastic expansion process, in which the granules during the The expansion process increases in volume.

Example 1 1000 g of clay dust with a grain size of 0.5 mm become 400 cbcm Added water and mixed the mass, so that a plastic pulpy mass is formed. 2 to 1 percent by weight of a liquefying agent, e.g. soda, added, so that the mass becomes more plastic to thinly liquid while stirring and gets thixotropic properties, so that the movement of the mass is maintained must become.

After producing such a pasty to thin-bodied mass a foam mass added. This show ace is made separately. Used in this to 100 cbcm of water about 2 g of a foaming agent, z. B. fatty alcohol polyglycol ether.

This results in a show ace of about 800 to 1000 cbcm, the nxnzehr the pulpy clay mass is filled.

This foam mass has a further liquefying effect on the pulpy mass, so that there is an intensive mixture between the clay mass and the foam mass.

The resulting mass has thixotropic properties; she must therefore be kept in constant motion, either by vibration or by stirring can happen. When the mixing process is finished, the movement of the mass be terminated. In this case the mass thickens due to its thixotropic properties immediately and stabilizes the foam it contains.

Example 2 1000 g of mineral dust are added to 400 to 500 cbcm of water. The water contains a liquefying agent in amounts of about 4 percent by weight, based on the amount of water. To this amount a binder, e.g.

Sulphite waste liquor in amounts of 0.1 up to 5 percent by weight, based on the total mass, added.

The foam mass is added to the pasty mass produced in this way, as in Example 1 explain in detail The addition of the binder has the advantage with this type of starting material that at the beginning of the firing process the mass does not tend to disintegrate or to trickle.

The total mixture produced in this way and containing the foam mass, is processed into granules with the help of known devices or in Molds poured and then fired.

After the form is fired, a stone is created, which is made into the thinnest platelets can be cut up.

It can, for example, Tiles are made.

Example 3 For the production of the pulpy mass from clay dust according to Example 1, hot steam can also be added instead of water. The amount corresponds the amount of water to be added.

-Expectations -

Claims (19)

Claims Process for the production of expanded, fired granules or molded bodies made of powdery mineral substances, in particular rock flour, E.g. clay dust, where the powdery mineral substances with water to form a pasty, malleable mass can be added, e t that after production of the pasty mass a foam mass is added, whereupon the entire mixture is fired. 2. The method according to claim 19 d a d u r c h g e k e n n z o i c h n e t that to reduce the viscosity of the pasty mass a liquefying agent, e.g. an electrolyte is added. 3. The method according to claim 1 d a d u r c h g e k e n n z e i c h n e t that soda, water glass or humic acid serves as the electrolyte 4th Method according to Claim 1, in which the foam mass consists of a foaming agent which foams when water is added. 5. The method of claim 1, d a d u r c h g e k e n n z e i c h n e tX that surfactants, fatty alcohol polyglycol ethers, fatty alcohol sulfate, Alkyl sulfonates, fatty alcohol ether sulfate, alkylphenol polyglycol ether, etc. are used will. 6. The method of claim 1, d a d u r c h g e k e n n z e i c h n e t that the show aces is 10 to 50 percent by weight of the starting aasse. 7. The method according to claim 1, d a d u r c h g e k e n n z e i c h n e t that 0.1 to 7.5 weight percent foaming agent, based on the water Amount of water to be added. 8. The method of claim 1, d a d u r c h g e k e n n z e i c h n e t that 20 to 50 percent by weight of water is added to the dry starting material will. 9. The method according to claim 1, d a d u r c h g e k e n n z e i c h n e t that de water 2 to 12 percent by weight liquefying agent, based on the amount of water to be added. 10. The method according to claim 1, d a d u r c h g e k e n n z e i c h n e t, that the seed mixture until the end of the mixing process in constant Movement is kept. 11. The method according to claim 1, d a d u r c h g e k e n n z e i c h n e t, that such substances are added to the total mixture that the mass the Withdraw water. 12. The method according to claim 1, d a d u r c h g e k e n n z e i c h n e t that such additives, e.g. sawdust, sulphite waste liquor, cellulose, talc, Bentonite, water glass, etc. are. 13. The method according to claim 1, in particular in the case of such pulpy masses, which tend to disintegrate under the influence of heat, that is to say c h n e, t that a binding agent is added to the pulpy liquid. 14. The method according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the binder is added before the addition of the foam mass. 15. The method according to claim 1, d a d u r c h g e k e n n z e i c h N e tt that sulphite waste liquor, dextrin or glue are used as binding agents. 16. The method according to claim 1, d a d u r c h g e k e n n z e i c h N e t that the total mixture in a lined with absorbent, but combustible material Mold is poured. 17. The method according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the form is made of absorbent and combustible material. 18. The method according to claim 1, d a d u r c h g e k e n n z e i c h n e t that paper or cellulose is used as an absorbent material. 19. The method of claim 1, d a d u r c h g e k e n n z e i c h n e t that the total mixture is processed into granules, and the granules contribute at a temperature between 900 and 17000 C.