LU87199A1 - PROCESS FOR THE MANUFACTURE OF EXPANDED PARTICLES BASED ON MINERAL WASTE AND INSTALLATION FOR CARRYING OUT SAID METHOD - Google Patents

Description

* Γ Λ -j Λ ΛΠΑ GRAND-DUCHY OF LUXEMBOURG

# 0¾¾ Minister of 1 ..? ....... 5.ΥΞ —........ 1.? ..?.,? ............ ..... jMMKI. Economy and the Middle Classes

- SKS. Intellectual Property Service ^ 4103 ........................................... ........... (= gS LUXEMBOURG

Patent Application

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Ύ ------------------------------------------------- ---------------------------------------------------------- ---------------------------------------------------------- ---- (î) I. Request

The company called: Paul Wurth SA (ολ 32 rueli ^ Hsace '' ............. ........... ........ ... ........ Γ ^ 'L_1122' "LuXQïOÂlItg ............................ '' '.... ...................... ......

represented by É.T. Freylinger & E. Meyers, ing. cons. in prop. undue .............. (3) 46 rue '^ acting in deposit (nt) this "April thirteenth" one thousand nine hundred eighty-eight __________________________ (4) at ___________ hours, at the Ministry of Economy and the Middle Classes, in Luxembourg: 1. this request for obtaining a patent for an invention concerning:

PrQcedé ..- de- f abr.icatxon — de — Expanded Partules -: -------------------------------- ( 5) to ...... ba.se..Ae ..., dêc.h.eis. „. Jiiin.émux ..... ei ™ .installa.tioa ____________________________________ for the implementation of this process _____________________________ 2 the description in language fr ahÇa._i.SP __________________________________ of the invention in triplicate; 3. ^ .HËÈ: E.® ___________________________ drawing boards, in triplicate; 4. the receipt of taxes paid to the Luxembourg Registration Office on __; 5. the delegation of power, dated from Luxembourg ------------------------------ Ie -JTISTT ^ B 8 --- ' 6. the successor document (authorization); declare) by assuming responsibility for this declaration, that F (es) inventors) is (are): (6) ± .. · .......... Carlo ... PAQUET .., ... .... 60 ...... rue .... da .... £ daoenfels, ...... BRIDEL ._. (. LiJxernbourg) ..---------- ----------------------- .2 .......... CQSie.i.lle .... MELAN. / ... ...: 4.3 ...... Bd ... Ch _______________________________________________ claims (s) for the above patent application the priority of one (s) application (s) of (7) ....... .................................................. ............... „.................................. .................................................. .... filed in (8) ___________________________________________________________________________________________________________________________________ on (9) ................................. .................................................. .................................................. .................................................. .................................................. ............. .................................................. ...-.........

under N ° (10) ------------------------------------------- ---------------------------------------------------------- ---------------------------------------------------------- ---------------------------------------------------------- ---------------------------------------------------------- --------- on behalf of (11) ................................... .................................................. .................................................. .................................................. .................................................. .................................................. ..

elect (elect) domicile for him / her and, if designated, for his / her representative, in Luxembourg ............................. .................................................. .....

46 rue du Cimet ière, 1 011 Luxembourg ...................... ................... .............................................. (12) requests (nt) the issuance of a patent for the subject described and represented in the abovementioned appendices, with postponement of this grant to -------------------. .d.ix ..-. top_______________________________________________________________________________________________________________________month. - (13) T / agent:., .. A ... ------------------- 1 .............. ..........— ....................................... .................................................. .................................... (14) y'y _ Π. Deposit Minutes

The above application for a patent for invention has been filed with the Ministry of the Economy and Middle Classes, Department of Intellectual Property ^ fïSxembourg, dated: April 3, 1988 / y “/ \ £ £ Pr. Minister Economy and Average Qasses,. (? \ / j "/” The head of the service! ^ has intellectual property, ”\ 1} · X & / / X _

Roosters - a68007 ~ __ / é.> _ EXPLANATIONS RELATING TO THE DEPOSIT FORM. / Π / Λ "γ (1) if applicable" Request for certificate of addition to the main patent, at the main patent application No ......... IS · du. ..... ...... ”- (2) enter the surname, first name, profession, Π a4 / address of the applicant, when the latter is an individual or the company name, legal form, address of the head office, when the applicant is a legal person - (3) enter ^ I the surname, first name, address of the authorized representative, industrial property attorney, provided with a power of attorney, if applicable: "represented by. acting as agent "I - (4) date of filing in full - (5) title of invention - (6) enter the names, first names, addresses of the inventors or the indication" (see) separate designation ( will follow) ", when the designation was or will be made in a separate document, or the indication" not to mention ", when the inventor signs or signs a non-mention document to be attached to a designation t,

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BL 4103 Descriptive memorandum filed in support of a Luxembourg patent application for:

Process for the manufacture of expanded particles based on mineral waste and installation for the implementation of this process by: Paul Wurth S.A.

32 rue d'Alsace - L-1122 Luxembourg t - 1 -

PROCESS FOR THE MANUFACTURE OF MINERRUX-BASED WASTE 5 PRRTICULE5 AND INSTALLATION FOR CARRYING OUT SAID METHOD

The present invention relates to a process for the production of expanded particles from mineral waste, which consists in adding to the ground mineral waste an expanding adjuvant, in forming nodules from this mixture and in causing the expansion of these nodules in a stream of hot gas. The invention also relates to an installation for implementing this method.

A process of this kind has already been proposed in the German patent application 33 24 1936. This process allows the recovery of industrial waste such as fly ash, secondary residues from the combustion of coal from power plants or sludge from dredging of ports. During the heating of the particles formed from the mixture of this waste and of the expanding adjuvant up to the softening temperature of the mineral particles, the gaseous emissions cause the particles to swell by the formation of closed cells. After cooling these expanded nodules, solid particles are obtained, of variable particle size 25 (C4 at 20 mm) and a specific weight which can vary between 0.2 and 0.8 g / cm3. The lightness, solidity and insulating power of these expanded nodules make them an excellent additive for building materials, such as concrete, and for insulation products. Unfortunately, poor control of the heating and the expansion phase of the nodules has not yet made it possible to develop this process up to the industrial stage. Indeed, the waste targeted by this process essentially consists of silica and aluminum oxide, which, during the critical phase of heating, pass to a pyro-plastic consistency stage and the particles have, therefore, tendency to clump together and remain stuck together during cooling.

The object of the present invention is to provide a new process of the type described in the preamble which makes it possible to reduce the risks of agglutination of the nodules during the expansion and cooling phase. Another object of the invention is to provide an installation for the implementation of this method.

To achieve this objective, the method proposed by the present invention is essentially characterized in that the unexpanded nodules are introduced into an upward flow of combustion gases from a burner and in that it is established above the burner a flui-20 disê bed in which the nodules are kept in suspension until sufficient expansion by heating, and in that the expanded nodules are separated by gravity from the combustion gases.

According to an advantageous embodiment, the expanded nodules are caused to separate by deflection against a cooled curved vault.

The combustion gases used for the expansion of the nodules are preferably used for the preheating of unexpanded nodules.

The final cooling of the expanded nodules is preferably carried out in a stream of air which, thereafter; is used as combustion air for the burner.

The installation for carrying out the process is essentially characterized by a vertical oven 5, the lower part of which is constituted by a burner, the upper part of which defines the region of formation of the fluidized bed, and the intermediate part of which communicates with a reservoir supply of unexpanded nodules, and a hopper for receiving expanded nodules 10 which is in communication with the upper part of the furnace.

The upper part of the furnace preferably has a water-cooled vault which deflects the expanded nodules horizontally in your receiving hopper where they are precipitated by gravity.

The top of the hopper is preferably connected by a pipe to the bottom of the feed tank. This is connected to the furnace by a sloping oblique pipe, which the unexpanded nodules cross under the ef-20 fet of gravity. This pipe is preferably for a view of a flow control valve.

The expanded nodules are evacuated from the hopper in an air cooling device which is connected by a line to the oven burner.

It is possible to modify the configuration of the expansion furnace so that, for unexpanded nodules of a specific density, said nodules are maintained at the start of their expansion process in suspension in the updraft of the hot gases. of combustion, their rate of rise at this time being zero or almost zero, and the speed of the combustion gases undergoes a progressive increase as they pass through the furnace while approaching the exit.

According to an advantageous embodiment of the invention, the speed of the combustion gases is caused to increase in the different zones of the furnace by the introduction of air or gases at different levels of the chamber.

According to another embodiment of the invention, the increase in the rate of rise of the combustion gases is obtained by the gradual narrowing of the section of the furnace.

flu as the expansion process progresses, The density of the nodules decreases considerably while their volume increases and the expanded nodules are thus easily ejected from the furnace by the action of ascending gases at a higher speed in addition.

The ratio of the end sections of the truncated cone 20 of the oven is chosen so that the rate of rise of the hot combustion gases increases as they pass through the oven, and this from a quantity which is such that , for unexpanded nodules of a specific density, said nodules are kept in suspension at the start of their expansion process in the updraft of hot combustion gases.

According to one embodiment, a number of gas or air injection nozzles are provided at different levels or zones of the oven.

Another embodiment provides the intro-

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- 5 - duction of a tube in the frustoconical oven along its longitudinal axis.

The two embodiments allow adjustment of the rate of rise Le of the gases (in particular its increase) when they pass through the oven.

Other features and characteristics will emerge from the appended drawings which show in more detail examples of execution of the installation according to the present invention. These represent: 10 Figure Ί, a schematic installation for the implementation of the method;

FIG. 2, a cross section of a first embodiment in accordance with the present invention showing injection nozzles at different levels of the oven;

Figure 3, a cross section of a second embodiment according to the present invention showing a conical tube introduced into the furnace;

Figure 4, a cross section of a combination of the two embodiments shown in Figures 2 and 3;

The essential part of the installation is constituted by an oven 10 with a refractory wall 12, the bottom of which is constituted by a burner 14. This burner develops combustion gases with a temperature of the order of 1300 ° C. This temperature can however be increased or lowered depending on the nature of the waste used.

The upper part 16 of the oven 10 has a very tapered shape diverging from bottom to top. Between the upper part 16 and the burner 14 is a spacer 16 to cause an acceleration of the ascending combustion gases.

A downward oblique pipe 20 connects the bottom of a supply tank 22 to the furnace 10 and enters 5 therein at the level of the throttle 18. A valve 24 provided in this pipe 20 makes it possible to adjust the flow rate of the particles which slide from the tank 22 into the oven 10 under the action of your gravity. The upper part of the tank 22 is connected through an airlock 24 to a filling device 26. The upper part of the tank 22 also communicates through an outlet pipe 28 with a suction pump and a filter not shown for gas evacuation.

The upper part of the furnace 10 communicates with a receiving hopper 30 in which the expanded particles are precipitated under the effect of gravity. The upper part of the wall 12 of the oven is preferably constituted by a vault 32 which is cooled with water and / or provided with jets for injecting a liquid 20 or cooling gas and which deflects the particles of so that these penetrate substantially horizontally into the hopper 30. The bottom wall 34 of this hopper 30 is associated with a water cooling system, eg coils, to ensure preliminary cooling of the particles which fall towards the bottom of this hopper.

The particles are evacuated from the bottom of the hopper 30 by an extraction system 36, eg a honeycomb rotor which pours the particles onto a conveyor belt in an air-cooling enclosure 38.

This enclosure 38 is connected through a circulation pump 40 and a pipe 42 to the burner 14 in order to use the cooling air heated in contact with the particles in the enclosure 38 as combustion air in the burner 14.

5 The upper part of your hopper 30 is connected by a line 44 to the bottom of the supply tank 22. This line 44 is associated with a siphon 46 or equivalent means for causing the deposition of solid particles entrained by the combustion gases leaving the 10 hopper 30.

During the operation of the installation, the nodules contained in the reservoir 22 slide through the channel 20 under the control of the position of the valve 24 in the furnace 10. At the level of the constriction 18, they are grasped and driven by The updraft of combustion gases. In the upper part of the furnace 10, these nodules remain in suspension in the gases to form a kind of fluidized bed. The height of the furnace and the speed of the upward movement of the combustion gases are determined in such a way that the rise time of the nodules allows the heating from 800 to 900 ° C., which is their temperature at the time of penetration into te oven 10, up to Their softening temperature which is of the order of 1250 to 1300 ° C sui-25 v the nature of the waste used.

The contact time between the particles and the combustion air is decisive. It is, in fact, necessary that the particles are sufficiently warmed to reach the softening stage to guarantee their expansion. On the other hand, once this temperature is reached, it is necessary to ensure a separation as rapid as possible between the expanded nodules and the hot gases in order to avoid an excessive softening of the nodules which would thus increase the risks of agglutination. This is the reason for which the vault 32 is cooled 5 and that it has a particular shape so as to project the expanded nodules in a horizontal direction inside the hopper 30. To avoid a rise of the expanded nodules in the hopper 30 by entrainment with the combustion gases, one could provide in your hopper 30, at the upper edge of the vault 32, a transverse grid, preferably cooled with water.

The combustion gases leave your hopper 30 through line 44 at a temperature of the order of 600 to 15,000 C. This temperature is sufficient to ensure preheating of the unexpanded nodules in the supply tank 22 in order to allow them to penetrate at a temperature of 800 to 900 ° C. in the oven 10.

FIG. 2 represents a part of the installation for manufacturing expanded particles described with reference to FIG. 1. The expansion furnace 10 with its refractory walls 12 which are either cooled metal walls or walls coated with refractories) has a shape of a truncated cone with a vertical axis 25, the small section (a) of which is at the bottom of the furnace 10 in the extension of the combustion chamber producing the hot gases. A number of gas or air injection nozzles 48, 48 'and 48' 'are arranged at different levels in the walls 12 of the oven 10. The 30 gas injection nozzles 48, 48' and 48 ' 'are connected to circular conduits 50, 50', 50 '' which are t tt l - 9 - supplied by conduits 51, 51 'and 51' '.

The nodules to be expanded are conveyed to the furnace 10 by a downward oblique pipe 20 which is connected to a supply tank.

5 The embodiment shown in Figure 3 shows the oven 10 also having the shape of a truncated cone identical or similar to that of Figure 2. A tube 52 is installed in the central axis of the oven 10. The tube 12 can, as in the example shown, be provided at its end and at different levels of openings 54, 54 ′ for injecting a gas or air into the furnace 10. Tube 52 can be introduced, as shown in dotted lines in Figure 2, more or less deeply along the Longitudinal axis in the oven 10.

15 The unexpanded particles consisting of nodules of mineral waste, in particular of silica oxide and aluminum oxide and of an expanding adjuvant, are introduced below into the furnace 10 by the downward oblique pipe 20. The ratio extreme sections 20 of the truncated cone of the furnace 10 is chosen so that the nodules to be expanded are, during their penetration into the furnace 10, kept in suspension in the ascending hot gases, fl the lower part these are the most larger and heavier ones which are in suspension, while the less large and less heavy nodules are found higher and higher in the oven 10. As they expand, the nodules go up in more chamber sections larger in order to reach, in the expanded state, a zero rate of rise in a well-defined section of the oven, from which it will be necessary to bring them to the outlet by means of an increase in the speed of the ascending gases. This increase is obtained by injecting cold or hot air into the section in question (Figure 2). Another way is to shrink the section in question by introducing from above into the oven 10 a conical tube 52 with a vertical axis (Figure 2). This tube 52 can usefully also be traversed by cold air which exits at the end of the tube through the orifices 54, 54 ′.

fl example, for an oven with the following dimensions: - Length: 2600 mm - diameter of the inlet section: 1Θ0 mm - diameter of the outlet section: 400 mm 15 and hot gases with the following characteristics:

- temperature: 1300 degrees C

- density: 0.2 kg / m3 20 - flow rate: 1.4 m3 / sec and a specific density of unexpanded nodules of 1500 kg / m3;

A nodule, unexpanded, assumed to be spherical in shape and whose diameter is between approximately 16 mm and 1 mm, is suspended at vertical or near-vertical speed at the time of its introduction into the current of hot gases. ascending.

The two methods described in relation to FIGS. 2 and 3 can also be combined as shown in FIG. 4 in which the same elements are identified by the same reference numbers as in FIGS. 2 and 3.

As the expansion time is a function of the dimensions of the nodules, the smallest nodules have the 5 shortest expansion time, and like the smallest nodules are suspended in the largest sections of the oven, i.e. at the top, the gas speed increase operation begins at the top of the furnace and continues towards the sections of more and more small 10 thereof, the progression being defined by the known expansion times. granules.

Introducing cold air into the oven has the beneficial effect of bringing the temperature of the surface of the nodules below the start of melting temperature before the nodules are evacuated outside. The introduction of cold air into the oven also produces a slow, gradual cooling of the nodules without thermal shock, thus reducing the creation of internal tensions which could cause the nodules to burst.

When all the expanded nodules are removed from the oven, a new charge of unexpanded nodules is introduced into it and the cycle begins again.

Several ovens can operate in parAllLE 25 depending on the desired flow rate.

Claims (16)

1. Process for manufacturing expanded particles based on mineral waste, which consists in adding to the ground mineral waste 5 an expanding adjuvant, in forming nodules from this mixture and in causing the expansion of these nodules in a gas stream characterized in that the unexpanded nodules are introduced into an upward flow of combustion gases from a burner and in that a fluidized bed is established above the burner in which the nodules are kept in suspension until with sufficient expansion by heating and in that, by gravity, the expanded nodules are separated from the combustion gases. 2. Method according to claim 1, characterized in that one causes the separation of the expanded nodules by deflection against a cooled curved vault. 3. Method according to claim 1, characterized in that one uses the combustion gases having served 20. the expansion of the nodules to preheat the unexpanded nodules. 4. Method according to claim 1, characterized in that the expanded nodules are cooled in a stream of air and in that this cooling air is used as combustion air in the burner. 5. Installation for implementing the method according to any one of claims 1 to 4, characterized by a vertical oven C10), the lower part of which is constituted by a burner C14), the upper part of which C16) defines the region for forming the fluidized bed and of which the intermediate part C18) commu * * - 13 - nique with a supply tank (22) in unexpanded nodules, and a hopper for receiving (30) expanded nodules which is in communication with the upper part (16) of the oven (10). 6. Installation according to claim 5, charac terized in that the upper part of the oven (10) has a vault (32) cooled with water which deflects the expanded nodules horizontally in your receiving hopper (30) where they precipitate by gravity . 7. Installation according to claim 5, charac terized in that the top of the hopper (30) is connected by a pipe (44) to the bottom of the supply tank (22). 6. Installation according to claim 5, characterized in that the bottom of the supply tank (22) is connected to the furnace (10) by an oblique pipe (20) sloping that the unexpanded nodules pass under the gravity effect. 9. Installation according to claim 7, characterized in that said pipe (20) is provided with a valve (24) for adjusting the flow rate. 10. Installation according to claim 5, characterized in that the expanded nodules are evacuated from the hopper (30) in an air cooling device (36) which is connected by a line C42) to the burner C14) of the oven (10 ). 11. Installation according to any one of claims 5 to 10, characterized by an expansion furnace (10) having dimensions such that the nodules of a certain density in the unexpanded state are maintained at the start of their expansion process suspended in te * »* * - 14 - updraft of hot combustion gases, their rate of rise being at this point neutral or almost zero, and the speed of combustion gases undergoes a progressive increase with As they 5 pass through the expansion furnace and approach the outlet. 12. Installation according to claim 11, characterized in that the increase in the speed of the combustion gases in the different zones of the oven is caused by the introduction of air or gas at different levels of the chamber. 13. Installation according to claim 12, characterized by injection nozzles (46, 48 ', 48' ') arranged in the wall C12) of the furnace (10) and by 15 circular pipes (50, 50', 50 * ') which supply the injection nozzles (48, 48', 48 '') with air or gas. 14. Installation according to claim 11, characterized in that the increase in the rate of rise Le of the combustion gases is obtained by the progressive narrowing of the section of the oven (10). 15. Installation according to claim 14, characterized in that the progressive narrowing is carried out by a conical tube (52) disposed in the oven (10) along its vertical axis. 16. Installation according to claim 15, characterized in that the conical tube (52) is provided with orifices (54, 54 ') at its end which allow the introduction of air and / or gas into the oven (10 ) by The tube (52).