DE2945061A1 - Expanded or foamed solid particles prodn. - from clays slags etc. using foaming agent in a slurry, then drying by heating - Google Patents

Abstract

Method of producing expanded or foamed solid particles, esp. granules, from clays, ash, slags and other mineral materials comprises mixing the raw material with a blowing or foaming agent to produce an emulsion, then drying with heat, causing blowing or foaming of mixt. to give granules with a bulk density below 350 (130-200) kg/cubic m. Useful esp. for insulating and fire resistant building materials in ready made form, such as blocks, bricks, boards, panels, etc. and as loose bulk material. The particles have closed, smooth pore free surfaces and a low density.

Description

Method and device for the production of distended

or foamed solid particles. The invention relates to a method for the production of expanded or foamed solid particles, in particular Granules made from thermally expandable and foamable raw materials such as clays, ashes, slag and other mineral substances, the raw materials with proportions of expanding and / or Foaming agents are processed into a foaming mass and this foaming mass is thermally Ways is dried and / or foamed.

The invention also relates to an apparatus for producing expanded or foamed solid particles.

Process for the production of granules with slight specificity Weights from thermally expanded mineral raw materials are known. Likewise is the use of such for example under the term "expanded clay" in the construction industry as well as long-established as so-called lightweight aggregates in insulation technology expanded solid particles known.

A detailed description of the state of the art with indications known manufacturing processes, an enumeration more suitable for this Starting materials and various processes, their mechanical and thermal Processing, as well as the properties of the expanded clay products obtained with it for example in the magazine "Die Ziegel industrie" magazine for the Brick, stoneware and refractory industry official organ of the federal association of the German brick industry, issue 22, 1966, pages 827 to 833 with the essay: "Production of expanded clay by the circulation flow process" In this article are also known devices and systems for processing and burning the Raw materials described. Depending on the types and properties of the raw materials used and corresponding manufacturing processes achieved bulk weights of the different Expanded clay products, for example, are rated at 350 to 600 kg / m3 (page 829, left Paragraph, line 4 from below) or with 600 to 1,000 kg / m3 (page 830, left column, Line 4 from below) or with 500 kg / m3 (page 833, right column, C.7).

It can be seen from this that the usual bulk weight range is better known Expanded clays in the order of magnitude between 350 and 1,000 kg / m3.

In the construction industry, natural lightweight aggregates are such as Pumice stone and artificial lightweight aggregates, such as expanded clay, have been around for a long time because of them special properties very sought-after building materials, their areas of application under other bricks, hollow ceilings, wall and roof panels, facade elements and other large-format prefabricated parts of the assembly building, as well as the area of the insulation include.

In the field of prefabricated components, lightweight aggregates have a preferred one Field of application found, because they allow considerable compared to heavy concrete Savings in transport weight can be achieved with lighter lifting devices and result from a significant relief of the structural weight of a building a lower load and dimensioning of the static supporting structure as well as the Foundations.

Other valuable properties are the excellent one at least partially, thermal insulation properties and noise reduction. Expanded granules have especially those with an approximately spherical surface and extremely light weight an optimum of inherent strength, preferably as a construction material in combination with a binder skeleton.

The beneficial properties of the expanded solid particles are but only achieved with strict adherence to the quality-determining characteristics, which through the Selection and preparation of the raw material, as well as from the strict adherence to defined operating parameters, in particular with the thermal treatment result.

Such quality features are, for example, the fine pores and Uniformity of the internal structure formed by gas inclusions, as well as a approximately uniform, preferably spherical outer shape of the granules in one relatively narrow grain size range, as well as a pore-free, approximately smooth structure of the surface.

Take with advancing developments within the construction industry the requirements for the quality of lightweight aggregates on the basis of expanded or foamed solid particles further, in particular are increased Requirements placed on the insulating effect, in particular against heat.

A field of application that has been developed for some time is elevation fire safety, for example in high-rise buildings, through the insulation of load-bearing components, in particular of the steel skeleton against the effects of Ilitze in the event of fire with the help of light insulation boards made using foamed solid particles. Extremely light bulk weights are aimed for, which if possible without Loss of mechanical strength of the aggregate should be achieved.

The object of the invention is therefore to process and Devices for the production of solid particles, in particular granules from thermally expandable raw materials so that they improve the production of extremely light expanded or foamed solid particles with bulk weights below 350 kg / m3, preferably in the bulk weight range between approximately 100 and allow 200 kg / m3.

The expanded or foamed granules should be as closed as possible, have a smooth and pore-free surface and consist of fine to finest cells have an existing internal structure.

A further aim is to make the thermal conductivity coefficients known and commercially available Expanded clays, which, for example in the case of loose bulk material, are in the order of 0.09 kcal / mh 0C are to be improved if possible in order to improve thermal insulation to be achieved with almost constant mechanical strength.

The invention further strives to improve the quality of the product to be produced To keep the product reproducibly constant within the narrowest possible tolerance limits, in order to be able to guarantee the quality properties safely.

Another part of the problem to be solved by the invention is therein seen, the production of an excellently expandable inflatable mass also using it such raw materials too allow which according to previous opinion and experience in producing puffed granules as poor or unsuitable were valid.

And finally, the invention aims at the method and to design the devices required for this in an uncomplicated and clear manner, that an effective control of both the procedure and that necessary for it Facilities as well as the product manufactured with it carried out without difficulty can be.

The object is achieved in that the expanding agent / or foaming agent mixed with the raw material for the production of an expanding mass in the form of an emulsion wird0 The invention has a number of advantages: The emulsion contains the actual blowing and / or foaming agent in extremely fine distribution, preferably in a liquid phase, which is therefore the case during dosing and mixing Can be processed excellently with the raw material, eliminating previous difficulties the exact volumetric or gravimetric dosing as well as the homogeneous admixture to be overcome. In addition, the kinetic toughness of the Bloating mass due to the sliding effect of the Emulsion reduced what contributes significantly to improving the mixing process. This will also hitherto existing difficulties overcome or at least considerably reduced.

Another advantage results from the fact that the expansion behavior is practical of most pyroplastic raw materials, including those that were previously not considered to be expandable have been kept, can be brought to an exactly defined level.

As a result, the kinetic toughness in the preparation of the inflatable mass is reduced by using an emulsion, either results from the same Mixing quality means considerable energy savings or the same amount of energy an improvement in the quality of the mix.

In an embodiment of the method it is provided that the admixture the emulsion to the raw material takes place in such an amount that the puffed and / or foamed granules in the bulk density range below 350 kg / m3 and preferably between 130 and 200 kg / m3.

According to the teaching of the invention can be expanded or foamed for the first time Solid particles are produced in such a low bulk weight range, which has so far been viewed as unreachable by the professional world.

In an embodiment of the invention it is further provided that the emulsion during the granulation process, especially when pelleting, as a binding liquid is added.

This measure gives sish advantages, especially in the so-called Dry process. Solid raw materials such as slate and Opalinus Clay are preferred or others ground finely and in a pelletizer with the addition of Binding water subjected to a floll granulation.

The admixed according to the invention as a binding liquid, the expanding and / or Emulsion containing foaming agent mixes and distributes itself intimately with the flour-like raw material and gives it much higher binding forces than water. As a result, the overall proportion of liquid used during pelleting is lower come to use, whereby thermal energy is saved in the drying process.

As a side benefit, there is another advantage from the anyway existing dosing device for the binding liquid when pelleting, adding an exact Allocation of expanding and / or foaming agent is achieved without there being any additional metering device is required.

Another embodiment of the invention provides that the emulsion in the preparation of the raw material, preferably after a Nahl- and / or before is mixed with an Ilisch and / or kneading process.

This measure results in what is known as wet processing For example, in the case of muddy raw materials, the advantageous possibility that processing steps that are necessary anyway, at the same time for intimate homogenization <les raw material to use with the emulsion, without it being a special one here Process step requires.

In this way it is achieved that the emulsion with the raw material under Saving energy is mixed intimately and preferably homogeneously.

In an embodiment of the method it is further provided that the emulsion soap, preferably soft soap, water and optionally an addition of emulsifier contains.

This has the advantages that one of the components mentioned The emulsion produced is inexpensive, it is particularly smooth and therefore particularly easy-to-use bulking compound results, which results in very good bulking behavior is achieved.

Another embodiment provides that the emulsion soap, oil and Contains water. These components are optimally coordinated with one another in accordance with the blazing result achieved in this way at the discretion of the specialist and can be determined without difficulty by experiments in the laboratory.

According to other embodiments of the invention it is provided that the Emulsion contains sulphide waste liquor and oil. But it can also produce petrochemical waste such as bitumen and other similar substances.

In addition, the emulsion can optionally contain a gaseous component contain, preferably air.

As a result, an expanding mass produced with this emulsion is already given before the thermal process, a pore volume with a homogeneously distributed plurality microscopic gas inclusions. The raw inflatable mass therefore has on the one hand a suppleness favoring the granulation process on and on the other hand the drying and swelling process has a beneficial effect.

It is provided that the emulsion optionally at least partially is made using hot water and / or steam.

It has also been found to be advantageous that the emulsion has a half-life of 1 to 60 minutes, preferably 10 to 30 minutes. In this way, the emulsion is only maintained until it is homogeneous Mixing with the raw material is complete.

In a further embodiment of the method it is provided that the granules in the course of the drying process up to a temperature just below the pyroplastic Viscosity range are heated.

This temperature limit depends essentially on the type and property of the raw material used and is preferably determined beforehand in a laboratory test.

The heating of the granules up to this temperature limit is for the inventive production of extremely light expanded and foamed solid particles therefore advantageous because the subsequent actual swelling and foaming process in the pyroplastic viscosity range from the granules at a relatively high speed must be completed with a relatively short residence time.

In an expedient embodiment of the invention, this is done by that the expansion and / or foaming process in the pyroplastic viscosity range during rolling movements of the granules on a hot furnace wall and under the action of radiation and Convection of hot flame gases is carried out, and that the height of the bed is kept as low as possible. This results in an advantageous manner a more uniform one, more or less independent of the differences in size of the granules Swelling process without the granules sticking together or sintering together. In particular due to the action of radiant heat in the The rolling movement of the granules creates an even, firm and closed surface achieved.

It is important in an embodiment of the invention that the height of the bulk bed is a maximum of 15 times the average grain size of the calcined granules, and preferably about 8 to 10 times the amount.

With the invention is also the use of the according to the invention Process produced granules intended for the production of lightweight construction elements, especially for thermal insulation, by molding these elements using them of curable binders. Plastic adhesives, foaming ones, can be used as binders Plastic adhesives, bitumen and the like, as well as cement, cement foam and inorganic Foams such as asbestos foam can be used.

A device for carrying out the method according to the invention is characterized in that this is a device for manufacturing and / or Has allocation of an emulsion. And finally there is a device for making it the foamed solid particles according to the invention, characterized in that these two downstream gas sides that are connected to one another Having rotary kilns, the second rotary kiln in the direction of material movement, in which the actual expansion or foaming process carried out a diameter / length ratio of less than 1: 6, preferably between 1: 1 and 1: 3 and a peripheral speed of the order of 50 m / min. having.

This arrangement has the advantage that the granules pass through the device can be manufactured and fired continuously, whereby the known advantages of continuous operation namely uniform and therefore Gentle thermal load on the hot furnace walls and the achievement of easily controllable Operating parameters for generating a uniform quality standard, in particular be made possible in the bloating process.

In the following the invention is based on exemplary embodiments in Explained in more detail in the drawing: FIG. 1 shows a system for wet processing according to the invention in a block diagram, FIG. 2 shows a system for dry processing according to the invention, also in the block diagram.

In the wet processing according to FIG. 1, the raw materials are taken from storage bunkers 1 and 2 by means of gravimetrically metering extraction devices 3 and 4 deducted in a certain proportion and, as indicated by arrow 5, fed to the kneading mixer 6 in the pit-moist state. Pit-moist clay can for example contain up to approx. 35 96 water parts. The kneading mixer 6, in the example shown a continuously operating twin-shaft compulsory mixer of known type the function that is more or less plastic raw materials due to the water content to mix, to homogenize and to plasticize in the process.

In the task 7 of the mixer 6 according to the teaching of the invention given a blowing agent in the form of an emulsion, as shown by the arrow 8 schematically indicated.

To add the emulsion in a constant, predetermined ratio to be able to dose the raw material quantity, this is controlled by a volumetric Allocation device 9 metered. For this purpose the gravimetric dosing Extraction organs 3 and 4 through control lines 10 and 11 with a computing and control unit 12 in connection, which calculates the dispensing amount for the emulsion and a target value forms, and this with the control line 13 to the drive 14 of the volumetric metering Device 9 switches on. The desired ratio of raw material and emulsion will be preselected with the aid of the digital input unit 15 and the arithmetic and control unit 12 connected through the signal line 16.

To produce the emulsion, for example from components A, B, C and D is a device for batch formation with the setting members 17 to 20 provided, which the components, for example oil, soap, bitumen, emulsifier and water, mixed in a certain amount and fed to an emulsifying machine 21, which the component mixture is processed into a homogeneous emulsion.

The description of the function of an emulsifying machine is given in the context of this example was not received because this is a known, commercially available device represents, the mode of operation of which is known to the person skilled in the art.

The finished emulsion is through the pump 22 and the line 23 to Dosing device 9 promoted.

The kneading mixer 6 processes the raw materials together with the emulsion to a homogeneous plastic inflatable mass, which, as indicated by arrow 24, in a downstream crushing and rolling mill 25 to improve homogeneity and processability is re-shredded and milled. The discharge of the rolling mill 25 is fed into a box feeder 27 by a conveyor device 26, which essentially has the function of an intermediate bunker. From there the prepared inflatable mass in gravimetrically or volumetrically dosed quantities abandoned with the take-off element 28 of an extruder 29. Opposite the discharge nozzle 30 of this extruder 29 is a Device 31 with a rotating Knife arranged, which the exiting strands of material in granules of defined Size chopped up. The green granules fall, as indicated by arrow 32, in the intermediate bunker 33 and are from this with the metering discharge organ 34 to the drying and expanding oven 35 in a controlled amount through the feed chute 36 given up. This consists of a first rotary kiln part 37 with a comparatively elongated diameter-aspect ratio, while the subsequent The inflatable part 38, for example, has an approximately square diameter-length ratio having.

Granules carried in through the chute 36 are in the furnace part 37 first dried in zones, then heated, and reach temperatures by, for example, 750 to 850 ° C. directly into the expandable part 38 of the rotary kiln 35. In it the granules are essentially under the influence of the flame radiation the flame 39 of the burner 40 with a high temperature gradient approximately shock-like heated to expansion temperature, in a manner known per se by dissociation of the blowing agent through gas formation in a large number of microscopic areas a foam structure is created, which consists of a large number of small and smallest of cell-like walls surrounded gas inclusions. The surface of the granules is due to the rolling process in the rotary kiln 35 approximately spherical and as The result of the pyroplastic state occurring in the swelling process is a smooth and solid outer skin.

The expanded or foamed granules fall out of the expanded part 38 into the cooler 41, in which it is conveyed by the fan 42 in a known manner Cooling air are cooled to the extent that they are in a downstream storage and Shipping bunker 43 can be stored and shipped from there, like this is indicated purely schematically by the arrow 44.

The dry preparation according to FIG. 2 only differs in the processing part in that the raw material removed from the storage bunkers 50 and 51 both dried and during the drying, and / or, conversely, be dried during the grinding.

This mill-drying system 79 comprises the tube mill 52, the air flow classifier 53, the separator for ready-ground material 54, the circulating air and exhaust fan 55 and the hot gas line 56. The finished product obtained in the separator 54 in flour fineness is through a discharge lock 57 in a regulated amount by a transport device 58 abandoned the pelletizing plate 59. In this, build-up granulation with With the help of a known rolling process in the inclined pelletizing plate 59 the Flour with the addition of binding liquid through granulation to solid pellets processed. A plant 80 is used to prepare the emulsion intended, which individual components, for example A to D, as well as water, in each case regulated Amount mixed together, the amounts of the individual components being determined by the distribution organs 60 to 64 can be set. With 65 an emulsifying machine is referred to, which the premixed mixture ready-mixed, homogenized, emulsified and the emulsion storage tank 66 leads. From there the emulsion becomes volumetric through line 67 dosing dispensing device 68 abandoned. This receives the for setting the Quantity required control pulses through the control line 69 from the computing and Control unit 70, which on the one hand through the control lines 71 and 72 signals from the gravimetric allocation organs 73 and 74 of the raw material bunker 50 and 51 receives, and on the other hand, a setpoint switch-off by the control line 75 from the digital Preselection and input unit 76 The green granules are temporarily stored in bunker 77, and from this through a gravimetrically metering discharge device 78 of the chute 36 of the rotary kiln 35 allocated. The pyrotechnic part including the rotary kiln 35 otherwise corresponds to the arrangement shown in FIG. 1 and is therefore shown in FIG. 2 not further elaborated.

The exemplary embodiments shown and described in FIGS. 1 and 2 are merely representative of a multitude of other possibilities that both in the processing plant part as well as in the pyrotechnic plant part - as is known per se - are conceivable and possible.

The device associated with each system is essential to the invention for the preparation and input of an emulsion in a certain proportion to the given one Raw material, the invention is further explained below using an example.

Example A sample of 100 kg montmorillonite (Al203, 4 SiO2, H20) with a water content (pit moisture) of approx. 25 to 33% is used for dry processing ground to a grinding fineness of 98% less than 90 µ by means of a grinding-drying system.

The residual moisture in the clay powder is approx. 3 to 5%.

The grain spectrum of the ground material shows the following structure: 90 - 60 µ = = 5, 60 - 40 u = 11, <40 = 84, 'From the flour, adding 10 to 15% binding liquid (water) granules called "green granules" on one Granulating plate manufactured. After classification with the elimination of oversized and undersized grains the grain range of the green granulate is between 3 and 7 mm, of which 46% is in the range of + 4% of the target grain (5 to 7 mm).

The granules are dried in a dryer up to a temperature of approx. 850 C and immediately afterwards expanded in a rotary kiln.

Three comparison tests are carried out each time, namely: a) without the addition of blowing aids b) with blowing aids according to the prior art c) with blowing aids according to the invention There are three different ones used Emulsions: Emulsion I = 2.5% soap (green soft soap) + 1.5% oil (mineral waste oil approx. 30 ° E) + 0.3% emulsifier (methyl cellulose) + 95.7% H20 Emulsion II = 8% sulphide waste liquor + 1.4% oil (mineral waste oil approx. 30 ° E) + 90.6% H2O Emulsion III = 5% sulphide waste liquor + 1.5% bitumen + 93.5 5 'H20 The result is the following The table shows: Base material montmorillonite montmorillonite montmorillonite montmorillonite Montmorillonite blowing agent without alkali carbonate Emulsion I Emulsion II Emulsion III Addition in% ./. 1.5% 10% 7% 5% preheating ° C 850 850 850 850 850 expansion temperature ° C 1,265 1,260 1,255 1,255 1,255 Grain range of green granules mm 3 - 7 3 - 7 3 - 7 3 - 7 3 - 7 Grain range of the expanded granules mm 3 - 10 5 - 12 8 - 18 8 - 20 8 - 20 bulk weight kp / m³ 950 755 140 160 155

Claims (19)

PateIltansDrüche method of making expanded or foamed Solid particles, in particular granules, made from thermally expandable and foamable Raw materials such as clays, ashes, slag and other mineral substances, whereby the raw materials are processed into an expanding mass with proportions of blowing and / or foaming agents, and this is thermally dried, expanded and / or foamed, d a it is indicated that the blowing and / or foaming agent is part of the raw material is added to produce an expanding mass in the form of an emulsion. 2. The method according to claim 1, characterized in that the admixture the emulsion to the raw material takes place in such an amount that the puffed and / or foamed granules in the bulk density range below 350 kg / m3 and preferably between 130 and 200 kg / m3. 3. The method according to claim 1 or 2, characterized in that the Emulsion during the granulation process, especially when pelleting, as a binding liquid is added. 4. Device according to one of claims 1 to 3, characterized in that that the emulsion is used during the preparation of the raw material, preferably after a grinding and / or is added before a mixing and / or kneading process. 5. Veifahren according to one of claims 1 to 4, characterized in that that the emulsion is intimately and preferably homogeneously mixed with the raw material. 6. The method according to any one of claims 1 to 5, characterized in that that the emulsion soap, preferably soft soap, water and optionally a Contains addition of emulsifier. 7. The method according to any one of claims 1 to 5, characterized in that that the emulsion contains soap, oil and water. 8. The method according to any one of claims 1 to 5, characterized in, that the emulsion contains sulphide waste liquor and oil. 9. The method according to any one of claims 1 to 5, characterized in, that the emulsion contains petrochemical waste such as bitumen. 10. The method according to any one of claims 1 to 5, characterized in that that the emulsion contains a gaseous component, preferably a proportion of air. 11. The method according to any one of claims 1 to 10, characterized in, that the emulsion at least partially using hot water and / or Water vapor is produced. 12. The method according to any one of claims 1 to 11, characterized in that that the emulsion has a half-life of 1 to 60 minutes, preferably 10 to 30 minutes has min. 13. The method according to any one of claims 1 to 12, characterized in that that the granules in the course of the drying process up to a temperature limit be heated just below the pyroplastic viscosity range. 14. The method according to any one of claims 1 to 13, characterized in, that the expansion and / or foaming process in the pyroplastic viscosity range during rolling movements of the granules on a hot furnace wall and under the action of radiation and Convection of hot flame gases is carried out, and that the height of the bed is kept as low as possible. 15. The method according to any one of claims 1 to 14, characterized in that that the height of the bed is a maximum of 15 times the average Grain size of the fired granules and preferably about 8 to 10 times the amount is equivalent to. 16. Use of the prepared by the process according to Claims 1 to 15 Granules for the production of lightweight construction elements, especially as insulation materials, by molding using hardenable binders. 17. The method according to claim 16, characterized in that as a binder Plastic glue, foaming plastics, bitumen and the like as well as cement, Cement foam and inorganic foams such as asbestos foam can be used. 18. Device for performing the method according to one of the claims 1 to 15, characterized in that this one device (9 to 22 and 60 to 76) for the production and / or allocation of an emulsion as a branch ** 19. Device according to claim 18, characterized in that these two downstream, Has rotary kilns (37, 38) connected to one another on the gas side, wherein the second rotary kiln (38) in the direction of material movement, in which the actual expansion or foaming process is carried out, a diameter / length ratio less than 1: 6, preferably between 1: 1 and 1: 3 and a peripheral speed on the order of 50 m / min. having.