MXPA05006823A - Treatment of granular solids in a fluidized bed with microwaves - Google Patents

Abstract

This invention relates to a method for the thermal treatment of granular solids in a fluidized bed (3, 3a) which is located in a fluidized-bed reactor (1, 1a), wherein microwave radiation is fed into the fluidized-bed reactor (1, 1a) through at least one wave guide (5), and to a corresponding plant. To improve the efficiency of the microwave irradiation, the irradiation angle of the microwaves is inclined by an angle of 10°to 50°, in particular 10°to 20°, with respect to the principal axis (11) of the fluidized-bed reactor (1, 1 a).

Description

PROCESS AND PACKAGE FOR THERMAL TREATMENT GRANULATED SOLIDS ON A TURBULENT BURN Field of the Invention The invention concerns a process for the thermal treatment of granulated solids in a turbulent bed which is in a turbulent bed reactor where microwave radiation is fed at least with a tubular waveguide to the turbulent bed reactor fluidized, as well as a corresponding installation.

BACKGROUND OF THE INVENTION There are several possibilities of coupling a microwave source in a fluidization layer reactor. These include, for example, a covered tubular waveguide, a slot antenna, a conjunction of couplings, a bypass septum, a coaxial antenna filled with gas or another dielectric, or a closed tubular waveguide with a transparent substance to the microwaves (window). The uncoupling of the microwave from the introduction duct can be achieved in different ways. The microwave energy can be transported theoretically without losses in tubular waveguides. The reaction of the tubular waveguide results in the logical development of a coil and capacitor electrical circuit towards very high frequencies. An electrical circuit of this type can also be operated theoretically without losses. By raising the resonance frequency the coil of an oscillating electric circuit a coiled medium is formed which corresponds to one of the sides of the section of a tubular waveguide. The capacitor is transformed into a plate capacitor which also corresponds to the sides of the section of the tubular waveguide. In the real case, an oscillating circuit loses energy due to the ohmic resistance in the winding and in the condenser. The tubular waveguide loses energy due to the resistance of the tubular waveguide wall. From an oscillating electrical circuit, energy can be diverted, applying a second oscillating circuit that takes energy from the first. In an analogous way it can be achieved, by flange adjustment of a second tubular waveguide to a first tubular waveguide, to decouple energy from it (transfer of tubular waveguides). If the tubular waveguide is closed by a short circuit closure behind the coupling area it is even possible to divert all the energy to the second tubular waveguide. The microwave energy in a tubular waveguide is enclosed by walls that are electrically conductive. Wall currents flow in the walls and in the section of the tubular waveguide there is an electromagnetic field whose field strength can be several times 10 KV per m. If an electrically conductive rod antenna is inserted in a tubular waveguide, it can directly deflect the potential difference of the electromagnetic field and radiate it back to its end appropriately (uncoupling by antenna or tip). An antenna rod that enters through an opening in a tubular waveguide and touches the wall of the tubular waveguide elsewhere can also extract or remove the currents directly from the wall and can also radiate them at its end if the guide of tubular waves is closed after the place of coupling of the antenna by a short-circuit partition, also in this case all the energy of the tubular waveguide can be diverted to the antenna. If the lines of the wall currents in tubular waveguides are interrupted by cutting, the microwave energy comes out through those cuts of the tubular waveguide (decoupling by cutting) since the energy can not continue its flow in the wall. The wall currents in a rectangular tubular waveguide flow in the middle of the wide side of the guide parallel to the center line, and in the middle of the narrow side of the tubular waveguide perpendicular to the center line. Cross sections on the wide side and longitudinal cuts on the narrow side therefore uncouple microwave radiation from tubular waveguides. Microwave radiations can be driven by electrically conductive hollow profiles of the most varied geometry, provided that the measures are reduced below certain values. The exact calculation of the resonance conditions is mathematically very complex since ultimately Maxwell's equations (nonlinear non-stationary differential equations) have to be solved with the corresponding edge conditions. However, in the case of a rectangular or circular section of sections of tubular waveguides, the equations are simplified to such an extent that they are analytically resolved, and for this reason they make visible problems in the design of tubular waveguides and make them easily soluble. Due to that and based on the relative simplicity of its construction in the industry, only rectangular or cylindrical tubular waveguides are used which are also preferably used by this invention. The rectangular tubular waveguides used are normally regulated in English literature. These normal measures were introduced in Germany so they partly result in different dimensions. According to the rule, all industrial 2.45 GHz frequency microwaves are equipped with a rectangular tubular waveguide of type R26 that has a cross section of 43 by 86 mm. In tubular waveguides there are different states of vibration: in the transverse electric mode (TE MODE) the electric field component is perpendicular to the direction of the tubular waveguide and the magnetic component in the direction of the tubular waveguide. In the transverse magnetic mode (MODE TM) the magnetic field component is perpendicular to the direction of the tubular waveguide and the electrical component in the direction of the tubular waveguide. Both states of vibrations can occur in all directions with different MODE numbers (eg TE-1-1, TM-2-0). A process for thermal treatment of granular solids is known from US Pat. No. 5,972,302 where sulfidic minerals are subjected to microwave assisted oxidation. This is mainly the roasting of pyrite in the fluidized bed where the microwaves directed to the fluidized bed favor the formation of hematite and elemental sulfur and suppress the formation of SO2. It is worked there in a stationary fluidized bed that is irradiated by the microwave source directly above it. With that the microwave source or the place of entry of the microwaves necessarily enters with the gases, vapors and powders that emanate from the fluidized bed. European Patent EP 0 403 820 Bl discloses a process for drying substances in a fluidized bed where the microwave source is outside the fluidized bed and the microwaves are guided by means of a tubular waveguide into the bed fluidized There, one often comes to reflections of microwave radiation in the solids to be heated, so that the degree of activity is reduced and the microwave source may be damaged. Furthermore, tubular waveguides of open microwaves generate sedimentation of powders in the tubular waveguide that can absorb part of the microwaves and can damage the microwave source. This can be avoided by windows that are transparent to the microwaves that close the tubular waveguide between the reactor and the microwave source. However in this case deposits on the windows lead to reductions in microwave radiation.

Objective and Compendium of the Invention The basic task of the invention consists in making the introduction of microwaves in a stationary or circulating turbulent fluidization layer more efficiently and protecting the microwave source in better shape. This task is solved according to the invention in a process previously specified essentially by the fact that the angle of introduction of the microwaves is inclined at an angle of 10 ° to 50 °, preferably between 10 ° and 20 ° to the main axis of the bed reactor (fluidized). According to the invention, the angle of introduction alpha can also be adjustable. Electromagnetic waves are transverse waves, and therefore have a direction of polarization where the direction of the electric field is parallel to the generating dipole, and the magnetic activation is perpendicular to it. To introduce the maximum microwave energy in the substances to be activated, the angle of reflection must be kept to a minimum. It is known that the degree of reflection depends on the irradiation angle, the diffraction index of the substance, and the direction of polarization. Since the substances to be activated in the fluidized bed are minerals, materials to be recycled, or waste materials that are resting non-planarly on a grid or circulating in the fluidization layer with the gas that is introduced into the reactor space, there is no specific plane on which microwave radiation acts. In the microwave introduction of several microwave sources, the microwaves reflected in the reactor space form standing waves in various ways. These modes are also generated in microwaves that come from a single source of microwaves since the microwaves are reflected in several directions in the wall of the reactor. These microwaves intensify each other by the amplification of the amplitude in some areas. With that, a number of standing waves is generated. Surprisingly it has been shown that, especially at an irradiation angle of the microwave of 10 to 20 ° with respect to the main axis of the reactor, the minimum of reflection can be obtained and with that a greater degree of action. Under the expression of the main axis of the reactor, the vertical axis of symmetry must be understood in particular. With that, the reflection toward the microwave source is also minimal. Furthermore, the microwave source is arranged for protection outside the fluidisation layer or stationary or circulating turbulence, where the microwave radiation is introduced into the reactor with at least one tubular waveguide. In a preferred embodiment, a gas stream is introduced through the tubular waveguide into the turbulent fluidized-bed reactor, which is also used for the introduction of microwave radiation. The coupling of the microwave radiation and also of the secondary current under an angle of 10 ° and especially of 20 ° in the fluidized reactor has proved especially convenient, because in this range of angles on the one hand the receding microwave power is minimum, and on the other hand, no sedimentation of dust has been observed inside the tubular waveguide. The degree of action of warming and work safety in this range are thus the highest. Depending on the properties of the fluidized bed they can also be reasonable from the point of view of the angular equipment between 20 and 50 °. Due to the continuous stream of additional gas from the guide it is safely impossible for dust or process gases to enter the tubular waveguide, expand to the microwave source and damage it, or form solids deposits in the guide of tubular waves. Due to this it is possible not to use, according to the invention, transparent windows to the microwaves in the tubular waveguide to protect the microwave source, as is common according to the time of the technology. In these there is the problem that sedimentation of powders or other solids in the window reduce the microwave radiation, or they can absorb it in part. Due to this, the open guides according to this invention are of particular advantage. An improvement of the process is achieved when the gas stream fed by the tubular waveguide contains gases that react with the fluidized turbulent bed and in the case of a circulating fluidization layer reactor can even be used for an additional fluidization of the turbulent bed . Therefore, a part of the gases that until now were added by other ducts to the fluidization layer is used to prevent the formation of dusts in the tubular waveguide. With this one can also not require a neutral wash gas.

A further improvement results when according to the invention the gas stream fed by the tubular waveguide has a temperature difference with the gases and solids that are in the fluidization layer reactor. This can be done as desired, adding added heat to the fluidised turbulent bed or cooling the turbulent bed. The heat treatment can not be used only in a stationary fluidized bed, but also in a circulating fluidized bed (circulating fluidization layer) where the solids circulate continuously between a fluidization layer reactor (drag or suspension reactor), a separator of solids connected to the upper area of the fluidization layer reactor and a pipe joining the solids separator to the bottom of the fluidization layer reactor. Normally the amount of crystallizing solid per hour corresponds three times to the solid contained in the fluidization layer reactor. A further advantage results from the fact that solid sediment formation in the tubular waveguide results from the continuous gas stream through the tubular waveguide. These solids sediments undesirably change the cross-sectional area of the tubular waveguide and absorb a part of the microwave energy, which was designed for the solids in the turbulent (fluidized) bed. Due to the absorption of energy in the tubular waveguide, it heats up strongly, so that the material is subjected to intense thermal wear. In addition, solid deposits in the tubular waveguide cause undesirable adhesions on the microwave source. In a circulating fluidization layer, an improvement of the existing process results when the microwave source is combined by the secondary gasification of the circular tube. With this the microwave radiation is conducted to the reactor at the preferential angle and the tubular waveguide is used at the same time for the addition of secondary gas. As a microwave source or as a source for electromagnetic waves, for example, a magneton or klistron is suitable. In addition, high frequency generators with corresponding windings or power transistors can be used. The frequencies of the electromagnetic waves emanating from the microwave source are normally in the range of 300 MHz to 30 GHz. Preferably ISM frequencies of 435 MHz, 915 MHz and 2.45 GHz are used. The optimum frequencies are conveniently determined for each application in a test run. The tubular waveguide consists in accordance with the invention wholly or mainly of electrically conductive material, for example copper. The length of the tubular waveguide is in the range of 0.1 to 10 m. The tubular waveguide can be straight or bent. Preferably, profiles with a round or rectangular section are used for this, where the dimensions are specially adapted to the frequency used.

The temperatures in the fluidized bed are for example in the range of 150-1200 ° C and it may be advisable to introduce additional heat into the fluidized bed for example by means of indirect heat exchange. For the measurement of temperature in the fluidized bed they serve isolated sensors, radiation pyrometers or fiber optic sensors. The gas velocity in the tubular waveguide (gas inlet tube) is adjusted according to the invention so that the Froude number of particles in the tubular waveguide is in the range between 0.1 and 100. For that the particle Froude number is defined as follows: with u = effective velocity of the gas stream in m / s ps = density of the particles or process gas entering the tubular waveguide, in kg / m3. Pf = effective density of the wash gas in the tubular waveguide, in kg / m3 dp = average diameter of the particles present inside the reactor during the operation of the reactor (or of the particles that are formed) in meters. g = gravitational constant in m / s. To prevent the entry of solid particles or process gases generated from the reactor to the tubular waveguide flows, among others, gas that serves as a washing gas through the tubular waveguide. Solid particles can be, for example, powder particles present in the reactor or also the solids to be treated. Process gases are formed in the process that takes place in the reactor. For the indication of certain Froude numbers of particles, the density ratio of the particles or process gases that penetrate with the flushing gas to adjust the velocity of the gas, which is responsible together with the gas, is taken into consideration according to the invention. velocity of the gas stream if the gas stream can carry the penetrating particles or not. This can prevent substances from entering the tubular waveguide. In most applications, a Froude number of particles between 2 and 30 is preferred in the tubular waveguide. In the process according to the invention, the granulated solids to be treated can be, for example, minerals and especially sulphurous minerals, for example They are prepared to obtain gold, copper, or zinc. In addition, recycled substances can be subjected to a thermal treatment in a fluidization bed such as, for example, oxide of the zinc-containing rollers or waste. If sulphurous minerals, such as arsenopyrite with gold, are subjected to the process, the sulfur is transformed into oxide and with that, by using an appropriate procedure, the process generates preferably elemental sulfur and only small amounts of SO2. The process according to the invention disaggregates the structure of the ore in a convenient manner, so that a leaching of the gold then gives higher yields. The arsenious iron sulfide (FeAsS) thus formed by the heat treatment can be deposited without problems. It is convenient that the solids to be treated absorb at least part of the electromagnetic radiation used and thus heat the bed. Surprisingly it has been shown that especially materials treated with high intensity fields can be leached more easily. Often other technical advantages can also be realized, such as shorter residence time or reduction of the required process temperatures. According to the invention, the solids can also be conducted through two fluidization layer reactors in series, for example two turbulence chambers separated by walls or impact walls in which the stationary fluidization layers are located and the electromagnetic waves coming from tubular waveguides. In that case the solid can migrate as a migration bed from a fluidization layer reactor to the neighboring fluidization layer reactor. A variant consists in that between the two turbulent (fluidized) beds of the two neighboring fluidization layer reactors an intermediate chamber is located connected to the two fluidized beds which contains a fluidized bed of granular solids, where the intermediate chamber is not provided. of tubular waveguide. Another variant of the process according to the invention consists in the separation of the two fluidized beds using a separating wall with an opening in the bottom. Especially convenient is that the process conditions, especially the temperature, fluidization gas composition, part of the energy, and / or fluidization rate may be different for each of several fluidization layer reactors. In a fluidized bed or several fluidized beds in series, the solids can be conducted, for example, first by a preheating chamber which is connected before the inlet to the fluidized turbulent bed. Furthermore, a cooled chamber for cooling the solid product can be connected behind the last fluidized turbulent bed used for the thermal treatment. Furthermore, the present invention deals with a special apparatus for carrying out the process established for the thermal treatment of granulated solids in a fluidized bed. The apparatus according to the invention consists of a fluidization layer reactor, a microwave source outside the fluidization layer reactor and a tubular waveguide for the introduction of microwave radiation into the fluidization layer reactor, where the tubular waveguide is inclined at an angle of 10 ° to 50 °, especially from 10 ° to 20 ° with respect to the main axis of the fluidization layer reactor.

Possibilities for continuation, advantages and possibilities of application of the present invention are also given in the following description, application examples and drawings. With that all and / or the features represented by the drawings belong by themselves or in any combination to the object of the invention, independently of its summary, claims or references.

BRIEF DESCRIPTION OF THE DRAWINGS Shown in: Figure 1 The thermal treatment of granular solids in a stationary fluidized bed, in schematic form. Figure 2 A variant of the process with circulating fluidization layer.

Figure 3, 4 and 5 Process variants in several fluidized beds.

Detailed Description of the Embodiments In Figure 1, the embodiment of the process according to the invention for the thermal treatment of particulate solids in a fluidization layer 3, also known as a fluidized bed, is represented. The equipment has a fluidization layer reactor to which the granular solid to be treated is added by a duct 2. There the solids generate in a chamber a fluidized bed through which a fluidizing gas flows, for example air. For this, the fluidizing gas is introduced from a gas distributor 4 to the fluidization bed 3. In the upper area of the reactor by fluidization layer 1 is connected to the chamber with the stationary fluidization layer 3, a tubular waveguide 5 leading to the microwave source 7. The tubular waveguide 5 is inclined at an alpha angle of 10 ° to 20 ° with respect to the upper axis 11 of the fluidization layer reactor 1. The electromagnetic waves coming from the source of The microwaves 7 are guided by the tubular waveguide 5 and introduced into the fluidization layer reactor 1. They provide, on the one hand, for the heating of the fluidisation bed 3. In addition, the gas 6 flushes the line 6, for example air or nitrogen, in the tubular waveguide 5 that continues to flow towards the fluidization layer reactor and prevents the entry of dust or process gases from the chamber with the fluidization layer 3 to the guide of tubular waves 5. In this way the microwave sources 7 are protected and at the same time deposits of "dirt" that absorb microwaves are prevented in the interior of the tubular waveguide 5, without the tubular waveguide 5 having to be closed by a transparent window to the microwaves. Due to the inclination angle, reflections of the microwaves introduced into the fluidization layer reactor are strongly reduced so that the electromagnetic radiation is better absorbed by the solids and the efficiency of the equipment and the process is increased. According to process requirements, further heating of the fluidized bed 3 is possible by means of an exchanger 8 arranged in the fluidized bed 3. Gases and vapors formed leave the chamber of the fluidization layer reactor through a duct 9 and they are led to a cooling and separation of known and not represented powders. The treated granulated solids are removed by a duct 10 from the fluidization layer reactor 1. In Figure 2 the fluidization layer reactor 1 is configured as a circulating fluidized bed (fluidized bed) reactor. The solids to be treated are introduced through the duct 2 to the fluidization layer reactor 1 and carried by the fluidization gas introduced into the fluidization layer reactor, thereby generating a circulating fluidization layer. The solids are then removed with the gas at least partially through a channel 18 of the fluidization layer reactor 1 and taken to a solids separator 12. The solids therein separated are recirculated at least partially through a gas duct. recirculation 13 to the lower area of the circulating fluidization layer of the fluidization layer reactor. A part of the solid can also be removed by means of the pipeline 14. Larger solids that are deposited downstream in the fluidization layer reactor can be removed by the removal duct 15 of the reactor 1. The fluidizing gas for the formation of the circulating fluidization layer for example air, it is brought through the duct 4a to the fluidization layer reactor 1, and arrives first at a distributor 4b before it enters through a 4c mesh in the fluidization reactor 1 where it is dragged especially fine granulated solid and generated as a fluidized bed , a layer of circulating fluidization. A tubular waveguide 5 links a microwave source 7 to the fluidization layer reactor chamber 1 through which, as in the equipment of Figure 1, the microwaves for heating by the granulated solids are fed to the microwave reactor 1 In addition, washing gas from a secondary gas exhaust system 6 enters the tubular waveguide 5 to prevent the entry of "dirt" and deposits into the tubular waveguide 5. The tubular waveguide 5 is inclined with a alpha angle of 10 ° to 20 ° with respect to the main axis 11 of the fluidization layer reactor 1 to minimize the reflection of the irradiated microwaves to the solids and prevent in conjunction with the gas stream dust deposits in the tubular waveguide 5. The microwave source 7 is located behind an angle of the guide 5 in that it deviates in relation to its principal axis approximately at the angle alpha. The secondary gasification 6 connected to a circular tube intersects the tubular waveguide 5 at an essentially axial angle.Also in this case the interior of the chamber may be provided with one or more heat exchangers for additional heating of the granular solids, which is not shown in Figure 2 to simplify this. The dust gas leaves the solids separator 12 through the pipe 9 and is first cooled by a cooler 16 before being taken to a dust remover 17. There the separated dust can be removed from the process or returned to the reactor chamber of the reactor. fluidization layer. According to FIG. 3, two fluidization layer reactors 1 and one are assembled in series, where between the chambers of the two reactors 1 and the intermediate chamber there is an intermediate chamber. In the three chambers the solids form a stationary fluidized bed 3, 3a which is crossed by the fluidizing gas. The fluidizing gas is carried to each chamber by a particular pipe 4a. The granular solids to be treated enter through the duct 2 in the first fluidization layer reactor 1 and totally treated solids leave the duct 10 from the second fluidization reactor 10. A partition 19 extends from the upper area of the chamber of the first reactor 1. down. However, it does not reach the bottom, so that an opening 20 is free in the bottom area, through which solids of the first fluidized bed 3 can enter the fluidized bed 30 of the intermediate chamber. The intermediate chamber reaches a second partition wall 21 on which the solids of the fluidized bed 3a of the intermediate chamber are moved to the chamber of the second fluidization layer reactor. The chambers of the two reactors 1 and are connected according to the equipment of Figures 1 and 2, tubular waveguides 5 with washing air pipes 6 and microwave sources 7, which are inclined at an angle alpha between 10 ° and 20 ° with respect to the main axis 11 vertical. The main axes of the reactors 1 and the are both vertical and parallel, so that in the drawing only one main axis has been shown. In that the angle alpha in reactor 1 differs from the angle alpha in the second reactor. This is reasonable especially if, for example, microwaves of different frequency are irradiated to the different chambers. Naturally, it can also be provided according to the invention that the two angles alpha for the two reactors 1, are equal. Additional heat exchange elements 8 may also be installed in the chambers of the reactors 1 and.

The gas area 22 on the fluidized bed 3 of the first fluidization layer reactor 1 is separated from the gas area 23 belonging to the chamber of the second reactor 11 and the intermediate chamber 10 by the vertical wall 19. For the areas of gas 22, 23 there are separate gas leaks 9 and 9a; with that, different conditions can be maintained in the chambers of the reactors 1 and specifically there can be different temperatures of addition of fluidization gases by separate gas addition ducts 4a. In addition, both microwave sources 7 can be equipped differently and cover different tasks. In particular, microwaves of different frequencies or energy can be generated and fed through the tubular waveguide. According to Figure 4 two fluidization layer reactors 1 and the are arranged directly in series without intermediate chamber where between them there is a separating wall 19. In the chambers of the two reactors 1, the solids generate a fluidized bed 3, 3a which is fluidized by fluidizing gas from several ducts 4a in parallel. The granular solids to be treated are added to the first fluidization layer reactor 1 through the pipeline 2 and the treated solids leave the fluidization layer reactor through the pipeline 10. From the upper area of the chamber of the first reactor 1 a first wall 19 it descends [there is a second wall] but does not reach to the bottom, so that at the bottom there remains an opening 20 through which solid of the first fluidized bed 3 can enter the fluidized bed 3a of the second fluidization layer reactor. To both chambers of the reactors 1 and are guided by two tubular waveguides 5 which are connected to microwave sources 7. Through both tubular waveguides microwave are fed to the two reactors 1, according to the specifications already described, to treat solids, which absorb microwave radiation for heating and reach the required process temperatures. The tubular waveguides 5 are again inclined with respect to the main axis 11 of the two reactors 1, the at respective angles alpha of 10 ° and 20 °. During microwave irradiation, wash gas flows through the wash air duct 6 into the tubular waveguides 5 to prevent settling. In the chambers of the reactors 1 and the heat exchange elements can be additionally installed 8. The gas area 22 on the fluidized bed 3 is separated from the gas area belonging to the second reactor by the vertical wall 19. There are different pipelines of gas leak 9 and 9a. With this different conditions can be maintained in the different chambers of the reactors 1 and the, in particular the temperatures or the compression of the gas phases can be different. Different fluidization gases can also be added through the corresponding ducts 4a. In addition, both microwave sources 7 can be equipped differently and perform different tasks. In the equipment according to Figure 5, the solids to be treated entering the duct 2 first enter an antechamber 31 and reach through a first intermediate chamber 32 in the second fluidization layer reactor 1. From this, the solids then pass through a second intermediate chamber to the second fluidization layer reactor and finally through a third intermediate chamber 33 in a cooling chamber 34, before the treated and cooled solids are removed by the pipeline 10. In the chambers of the fluidization layer reactors 1 and the respective tubular wave guides 5 with their corresponding microwave sources (not shown) for feeding the reactors 1 and the microwave by means of the principles already described. The tubular waveguides are also here inclined at an angle alpha between 10 ° and 20 ° with respect to the main axis 11 of the fluidization layer reactors 1,. In all chambers there are stationary fluidized beds to which fluidization gas is added by separate gas addition pipes 4a for each chamber. The exhaust gases emerge through corresponding ducts 9. Cooling equipment 35 for indirect heat exchange is located in the cooling chamber 34, whose cooling fluid, for example cooling water, is heated in the cooling equipment 35 and then carried by the pipe 36 to the heat exchanger. heat 37 in the preheating chamber 31. There the cooling fluid delivers a part of its heat to the solid in the corresponding bed, whereby a very economical thermal utilization is achieved. In order to make the microwave feed efficient in a stationary or circulating fluidized bed layer 3,3a and to protect the microwave source 7 from reflected microwave rays, the microwave source 7 is according to the invention outside the fluidization layer. 3, 3a and of the fluidization layer reactor 1, la. The microwave radiation is fed to the fluidization layer reactor 1, the at least one tubular waveguide 5 where the irradiation angle of the microwave is inclined by an angle of 10 ° to 50 °, preferably 10 ° to 20 °. °, with respect to the axis of the equivalent fluidization layer reactor 1, the.

Example Roasting of gold ore in a circulating fluidization layer The following table shows typical process parameters for a gold ore roasting. For comparison, data with and without 1 microwave irradiation according to the invention are presented. The microwave frequency in this case is 915 MHz.

Due to an increase of the reaction material by 30% with lower oil consumption, the capacity of the plant with lower emission by the use of microwaves that are introduced at an angle of 15 ° can be especially increased.

List of components Ref. Element Ref. Element 1,1a Layer reactor 13 Fluidization recirculation pipeline Intermediate chamber 14 Solids discharge pipe Solid cargo duct 15 Gas exhaust pipe 3.3a Layer, or fluidized bed 16 Cooler Gas distributor 17 Gas removal to Pipe 18 Channel b Gas distributor 19 Fluidisation separator partition Grid 20 Opening 5 Tubular wave guide 21 Separator partition 6 Gas inlet duct 31 Antechamber secondary Microwave source 32 Intermediate chamber 8 Heat exchanger 33 Intermediate chamber Gas extraction pipe 34 Refrigerant chamber 10 Solids discharge pipe 35 Refrigeration equipment 11 Main shaft 36 Pipe 12 Solids separator 37 Heat exchanger

Claims (15)

1. Claims 1. A process for the thermal treatment of granulated solids in a fluidized bed (3, 3a) which is in a fluidization layer reactor (1, la) in which microwave irradiation is fed with a minimum of one guide of tubular waves (5) in the fluidization layer reactor (1, la), CHARACTERIZED because the irradiation angle of the microwaves with respect to the main axis (11) of the fluidization layer reactor (1, la) is 10 ° to 50 °, especially 10 ° to 20 °.
2. 2. A process according to claim 1, CHARACTERIZED in that a gas stream is introduced through the same tubular waveguide (5) to the fluidization layer reactor (1, la).
3. 3. A process according to claim 2, CHARACTERIZED in that the gas stream introduced through the tubular waveguide (5) into the fluidized bed (3, 3a) contains reactive gases.
4. 4. A process according to any of claims 2 or 3, CHARACTERIZED because the gas stream introduced by the tubular waveguide (5) is further used for the fluidization of the fluidized bed (3, 3a).
5. 5. A process according to any of claims 2 to 4, characterized in that heat is added to the fluidized bed (3, 3a) through the gas stream.
6. 6. A process according to any of claims 2 to 4, CHARACTERIZED because the fluidized bed (3, 3a) is cooled by the feed gas stream.
7. 7. A process according to any of claims 2 to 6, characterized in that by the gas stream introduced into the tubular waveguide (5) solids deposits are avoided in the tubular waveguide (5).
8. 8. A process according to any of the preceding claims, CHARACTERIZED because the reactor consists of a minimum of two reactors of fluidization layers (1, la) that are separated from one another by partitions or partition walls (19, 21) so that the solids can move as a moving bed of one of the fluidization layer reactors (1) to the neighboring fluidization layer reactor (LA).
9. 9. A process according to any of the preceding claims, CHARACTERIZED in that the microwave source (7) is combined with a secondary gasification (6) of a circular duct and that the tubular waveguide (5) is also used for the addition of secondary gas.
10. 10. A process according to any of the preceding claims, CHARACTERIZED because the frequency of the microwave radiation is between 300 MHz and 30 GHz, preferably at the frequencies of 435 MHz, 915 MHz and 2.45 GHz.
11. 11. A process according to any of the preceding claims, CHARACTERIZED because the temperature of the fluidized bed (3, 3a) is between 150 ° C and 1200 ° C.
12. 12. A process according to any of the preceding claims, CHARACTERIZED in that the Froude number of particles Frp in the tubular waveguide (5) is 0.1 to 100, preferably 2 to 30.
13. 13. An apparatus for heat treatment of granulated solids in a fluidized bed (3, 3a) especially for carrying out the process according to the claims 1 to 12 with a fluidization layer reactor (1, the) a microwave source (7) located outside the fluidization layer reactor and a tubular waveguide (5) for feeding the microwave radiation in the fluidization layer reactor (1), CHARACTERIZED in that the tubular waveguide (5) is inclined at an angle of 10 ° to 50 ° specifically from 10 ° to 20 ° with respect to the main axis (11) of the layer reactor fluidization (1, the).
14. 14. An apparatus according to claim 13, CHARACTERIZED in that the tubular waveguide (5) has a rectangular or cylindrical section whose dimensions are specifically adjusted to the microwave radiation frequencies.
15. 15. An apparatus according to claim 13 or 14, CHARACTERIZED in that the tubular waveguide (5) has a length of 0.1 m to 10 m.