WO1993001141A1 - Process and device for the safe disposal of toxic residues - Google Patents

Abstract

Disclosed are a process and device for the safe disposal of toxic residues present in filter dust and in the sediments produced by chemical and industrial processes. The residues are mixed with finely divided used glass in a specific ratio. The mixture is placed in a furnace (14) in the form either of coated glass fragments or of compressed slugs (131); it is then subjected to heat treatment at eutectic temperatures until a homogeneous and chemically inert melt (18) is produced. This undergoes further processing to produce granules, powders, items of daily use and decorative objects.

Description

 Method and device for the safe disposal of toxic residues

The invention relates to a method and a device for the safe disposal of toxic residues according to the preamble of claim 1.

The solid or liquid waste of human society, which comes from settlement areas, chemical factories, electroplating plants, electronics industry (etching of printed circuit boards), metal industry (pickling, polishing), laboratories, hospitals, photo processing plants, tanneries, etc are brought to landfills, burned in incineration plants or collected as sludge in sewage treatment plants. The ashes of the incineration plants reach landfills or are used in road construction or for building materials, e.g. used as a sealing additive in structural concrete. The filter dusts resulting from the flue gas cleaning of the incineration plants are either used in the same way as the ashes or are mixed with cement and brought to a special waste landfill. The sewage sludge collected in the sewage treatment plant is either used as fertilizer or is sent to the landfill or in incineration plants. If the sludge comes from a chemical factory or electroplating facility, it goes to a hazardous waste landfill. The filter dust and sludge contain substances which, because of their water-soluble form, are toxic to living beings in the environment and poison the soil and the air. Such substances are the heavy metals Cd, Hg, Pb, Ti, also AI, Cr, Cu, C, S, Zn in the filter dusts and in the sludges of the galvanic plants AI, Cd, Cr, Cu, Fe, Mi, Ni, Zn A large number of toxic substances are also found in the ashes of special waste incineration plants which burn the waste from the chemical industry, tanneries, photo development institutes, hospitals and laboratories, the organic substances also being burned. The known methods of waste disposal that are still used today have the significant disadvantage of high toxicity for the

REPLACEMENT BUTT Living beings in the environment and, due to the large amount that accrues every day, take up excessive space in the landfill. This also applies if the volume of waste is reduced by incineration and the filter dusts are melted together by heat treatment. This filter dust melt remains toxic and is disposed of in a special waste landfill. This disposal method, which produces a melt of the filter dust by heat treatment, has, in addition to the stress on the landfill space, the further disadvantage that during the heat treatment of the filter dust, which is carried out in an oven at temperatures up to 1450 ° C. different chemical and physical properties of toxic components of the filter dust are left to their own devices. This results in a melt left to chance, which cannot be called a technically homogeneous material and which has a toxic effect on the environment after disposal.

The disposal or disposal of the waste has become a burden on the environment. To date, the problem has not been solved satisfactorily. This is related to the enormous amount of daily waste in the order of 50,000 tonnes per year for a region consisting of settlement areas, industry, trade and services with approx. 3 million inhabitants and employees. The capacity limit of the garbage dumps, especially the special garbage dumps, will soon be reached. The waste mountain continues to grow from year to year.

The object of the invention is to eliminate these disadvantages of the known disposal methods and to dispose of not only filter dusts but also sludges safely. In addition, the heat treatment is influenced in such a way that the end product is chemically inert, is therefore harmless to the environment and is used for a purpose which is built into the normal course of life. A further object of the invention is to be seen in the fact that the heat treatment is operated at lower temperatures in the order of magnitude of 800 ° C. to 1100 ° C. and thus with a lower energy requirement. Furthermore, the wear of the melting furnace is smaller because of the lower process temperatures, so that the service life of the system according to the invention is extended.

REPLACEMENT LEAF The objects are achieved by the features of the characterizing part of patent claim 1. Embodiments of the invention are explained in more detail with reference to the drawings.

Show it:

1 shows the entire system according to the invention in block diagram;

FIG. 2 the top view of a trough-shaped melting furnace as a sectional drawing;

Figure 3 shows the side view of the melting furnace of Figure 2 in a sectional view;

FIG. 4 shows the side view of a rotary kiln as a melting furnace;

Figure 5 The front view of the rotary kiln of Figure 4;

Figure 6 The side view of a shaft furnace as a melting furnace in a sectional view;

Figure 7 A graphical diagram to illustrate the

Melting equilibria in two-component and multi-component systems.

The block diagram of the system according to the invention from FIG. 1, which runs in continuous operation, shows several silos.

The silo 1 is provided for the storage of the filter dusts that occur during the flue gas cleaning of waste incineration plants. The electrostatic precipitators extract the toxic constituents from the flue gas of this incineration plant, which after the regular cleaning of the electrostatic precipitators as filter dust into the silo 1, e.g. by means of a conveyor belt. The filter dusts are delivered in the moist state as a so-called filter cake and have a grain size in the range of a few. Since the filter dust accumulates in large quantities up to 10 tons per day, silo 1 has a sufficiently large capacity.

The silo 2 is intended for the storage of lead-containing waste from the chemical or metal industry (e.g. comminuted lead plates from car batteries). The waste is in damp

REPLACEMENT LEAF Condition delivered and, for example, transported to the silo 2 via a conveyor belt. The Silo 2 has a large capacity because the waste is in the order of 10 tons per day.

In the silo 3, the sludge from the galvanic plants is stored. As is known, the impurities are removed from the galvanic baths and separated off in a filter press. The moist sludge, also known as filter cake, is produced in large quantities of up to 15,000 tons per year in Switzerland alone. Therefore Silo 3 also has a large capacity.

For storage in a silo there are also solutions and suspensions - such as Sodium hydroxide solution, copper sulfate - provided, the water content of which was greatly reduced in a known manner by distillation, evaporation or thickening.

Finely ground waste glass with a grain size of up to 3 - 6 mm is stored in silo 4. The recycling glass from household, trade and industry is called waste glass. The waste glass essentially contains the following components:

In the following further waste glass components are listed, the weight% of which can vary depending on the intended use.

A1 ₂ 0 ₃ , Fe ₂ 0 ₃ , MnO, MgO, Li ₂ 0, BaO, ^∑ -2 ⁰ 5 ' ^T1 2 ⁰ ' ^Sr0 ' ^B 2 ° 5' ZnO, F, Sb ₂ 0 ₅ .

Hollow glass, which means green, brown, white glass bottles, has additional components that are not listed here because they are generally known. Silo 4 also has a large capacity for a few tons of waste glass. The addition of waste glass to the filter dust or sludge has the advantages that the end product - i.e. the melt 18 melted in the melting furnace 14 has a great homogeneity and the undesired crystallization of the melt is prevented.

REPLACEMENT LEAF Because the crystallization of the melt would produce a product that is not chemically inert and would still be toxic to the environment. Furthermore, the use of waste glass in these quantities means the sensible use of this waste component and reduces the recycling of glass mountains. The mixing ratio of the components waste glass and filter dust or waste glass and sludge is in the order of 100: 1 to 1: 100. A preferred range is 5: 1 to 1: 2. The addition of waste glass also has the advantage that the transition of the chlorides, especially the heavy metal chlorides and heavy metals, from the melt 18 into the gas phase is reduced.

The silo 5 is provided for so-called flow promoters, which influence the flow properties of the melt 18 in the melting furnace 14. This silo has a smaller capacity because the flow sprayers are only required in small quantities.

Each of the silos 1, 2, 3, 4, which stores filter dust and sludge in the moist state, contains a vibrating device (61, 71, 81, 91) in the lower part, which ensures that the moist material slides evenly, so that no stagnation can occur in the operational process. Silo 5, which supports the flow promoter, also contains a vibrating device 101. The vibrating devices are only shown symbolically in FIG. 1 because they are generally known for silos with bulk material.

The output of each silo 1, 2, 3, 4, 5 is connected via a metering device 6, 7, 8, 9, 10 and conveyor belts 11 to the input of a so-called compactor 12. The dosing devices transfer as much material from the silo to the conveyor belts 11 as correspond to the desired mixture components and the desired mixture ratio. The mixtures with waste glass can contain both one component (filter dust or chemical sludge) and several components (filter dust and chemical sludge). These processes are programmed in the electronic control system 17, which will be explained in more detail later. In the input stage of the downstream compactor 12, a mixing device 121 is provided, which mixes the materials transported over the conveyor belts 11. Such a mixer

REPLACEMENT LEAF is known for granular material and is therefore only drawn symbolically in FIG. 1. It is also not described in detail. In special cases, the mixer can add water if the mixture does not have the required moisture. This is also controlled by the electronic control system 17. The mixing device passes the mixture on to a weighing and portioning device 122, which transfers the mixture, divided into portions of, for example, 5 kg, into a press 123, which presses each portion into a spherical or briquette-shaped blank 131. Depending on the type of melting furnace 14 used, spherical or briquette-shaped blanks 131 are used. Portions with other weights can also be produced. The weighing and portioning device for granular material and the pressing device 123 are known and are therefore not described. The blanks 131 located in the output stage of the compactor 12 are moved towards the exit at a certain speed, which is controlled by the electronic control system 17.

The spherical or briquette-shaped blanks 131 roll over the chute 13 into the melting furnace 14. This will be described later. The blanks are melted. New blanks follow and fall into the melt 18 which travels through the melting furnace.

It has been found that the mixture is advantageously conveyed into the melt of the melting furnace 14 as a pressed blank, such as only in the form of the dust-fine filter dust, sludge and the granular waste glass, because the unpressed material is not completely in because of the temperatures prevailing in the melting furnace the melt arrives. The dust-fine material would be blown away.

If the waste glass is broken up into pieces of glass or broken glass with a size of 5-6 mm, the mixture produced in the mixing device 121 can be conveyed directly into the melting furnace 14, i.e. without the weighing and positioning device 122 and without the pressing device 123. However, this requires special preparation of the mixture. The mixing device 122 contains a heater with which the moisture of the filter dust, sludge and thickened solutions or suspensions is extracted during the mixing process. During this process, they keep getting drier

REPLACEMENT LEAF materials on the surfaces of the glass pieces or broken glass become more and more solid and form a firm layer on the glass surfaces. The mixing device 121, which operates in continuous operation, pushes the coated pieces of old glass directly onto the chute 13 and then into the melting furnace 14.

The temperature in the melting furnace 14 is in the range from 800 ° C. to 1100 ° C., that is lower than in the known combustion of pure filter dust or industrial sludge. This advantageous lower temperature range results from the fact that the mixture is a two-substance and multi-substance system and therefore the eutectic melting temperature and the liquidus temperature of the melt 18 are low. This is explained in more detail in connection with FIG. 7. As a result of the lower melting and liquidus temperatures, there are the advantages of the longer life of the melting furnace and its lining with refractory material and the lower energy consumption. Further advantages of the low melting and liquidus temperatures are that fewer chemical compounds enter the gas phase and the viscosity of the melt is low. The low viscosity increases the throughput of the melt. This is very favorable for continuous operation of the melting furnace. With the prevailing temperatures in the melting furnace, there is still a small risk that chlorides will pass into the gas phase. In order to avoid a transition of chlorides, especially heavy metal chlorides, into the gas phase, additives, e.g. NaOH added to the waste glass in silo 4. At this point it should also be mentioned that the addition of waste glass has the advantages that the undesired crystallization when the melt cools is avoided, the melt becomes homogeneous and technically inert.

The furnace is heated either electrically, with oil, gas or coal. The electric heater consists of electrodes above the melt, between which an arc burns, which melts the material. The electrodes can be arranged in such a way that the melt is melted by means of alternating or three-phase current over the introduced electrodes by resistance heating or that the arc burns above the material to be melted. In the first case, the efficiency is better. Above all, prevented

REPLACEMENT LEAF the melting carpet lying on the melt emits a large amount of heat into the furnace and reduces the burn-up. The oil heater contains one or more nozzles arranged at specific locations, from which the flames emerge and sweep over the melting material. The gas heating also contains one or more nozzles arranged at certain locations, the flames of which sweep over the melting material. Coal heating is preferably used in the shaft furnace of FIG. 6. These different types of heating are known and are therefore not explained in detail. The melting furnace can have a constant temperature range or two or three different temperature ranges. This so-called temperature control depends on the properties of the materials which are to be melted and on the requirements placed on the properties of the melt. The temperature control in the melting furnace 14 can be adapted to the materials if filter dusts or sludges are used predominantly or exclusively. Thus, a uniform temperature can prevail in the entire melting furnace, or a starting temperature zone with a high temperature for melting the melting material of, for example, 1200 ° C., a medium temperature zone with a lower temperature of, for example, 1100 ° C. and an end temperature zone can be provided with a low temperature of eg 1000 ° C, so that the cooling process of the melt is carried out slowly. A slow cooling process improves the structure of the glass melt. It becomes homogeneous and chemically inert. It is also possible to provide only two temperature zones, for example the initial temperature zone with 1000 ° C and the end temperature zone with 800 ° C. The cooling process of the glass melt could then be carried out outside the melting furnace, for example via the melting channel 15 in the processing area 16 of the glass melt.

The melting furnace 14, which has a length of approx. 50 m, a width of 30 m and a height of 15 m, can be used as a furnace as shown in FIGS. 2, 3, as a rotary furnace as shown in FIGS. 4, 5 or as Shaft furnace according to Figure 6 be formed. Which type of furnace is to be used depends on the available spatial conditions at the location of the system according to the invention in FIG. 1, on the melting properties of the materials which are mostly obtained at this location and on the desired properties

REPLACEMENT LEAF the glass melt. The bottom of the melting furnace has an inclination in the embodiments of FIGS. 2, 3, 4, 5, so that the melt flows in the direction of the furnace exit and is mixed in the process. In the shaft furnace of FIG. 6, the melt flows downwards in a vertical direction and is mixed in the process. This is explained in more detail in connection with FIG. 6.

The flow rate of the melt 18 depends not only on the optimal temperature but also on the mixture components and on the mechanical forces which act on the melt due to the inclination of the melting path. Since the waste glass contains a large amount of Na_0, a good flow rate of the melt is guaranteed. If the viscosity of the melt should become smaller due to any circumstance and thus the flow speed lower, the flow promoter can be fed from the silo 5 to the blanks 131 via the metering device 10, conveyor belt 11, mixing device 121, weighing and portioning device 122 and pressing device 123 become.

If the other embodiment of the invention (no weighing and portioning device and no pressing device) is to be used, the flow sprotor passes from the silo 5 into the mixing device 121 and then together with the coated pieces of old glass or cullet via chute 13 in the melting furnace 14.

A sensor, which detects the viscosity of the melt, is arranged in the first third of the melting furnace 14 and sends its measurement data via line 142 to the electronic control system 17. As soon as the setpoint value of the flow rate set in the control system has fallen below, the control system outputs Via line 179 a signal into the metering device 10, which removes the flow sprotor from the silo 5 in a predetermined amount and adds it to the mixture until the melt 18 has reached its optimum flow rate again.

Depending on the type of furnace used (FIGS. 2, 3, 4, 5, 6) of the melting furnace 14 and the type of temperature control, the glass melt solidifies after it leaves the melting furnace and is pushed over chute 15 into the device designated 16 or the glass melt flows via channel 15 in the device 16. An

REPLACEMENT LEAF At this point it should be pointed out that the reference number 15 in FIG. 1 denotes both a slide and a channel. This device 16 symbolizes the further processing according to the invention of the solidified or non-solidified glass melt to give glass granules, used glass articles or decorative glass articles. The device 16, as shown in FIG. 1, can subsequently be provided on the melting furnace 14 or at other locations, for example in glass factories. In the first case, the glass melt flows into the device 16. In the second case, the solidified pieces of the glass mass are transported to the glass factories. In any case, laboratory samples are taken from the glass melt batches, which indicate the components and their mixing ratios. This ensures that the cheapest glass mixture is made available for the various glass articles. The glass melt or glass mass of the melting furnace 14 is homogeneous and chemically inert. This means that they are harmless for the production of glass articles, glass granules and flours as well as decorative glass articles.

Glass articles which are non-toxic to living beings are produced by generally known techniques such as blowing, pressing, rolling and drawing. Therefore, it is not discussed in more detail. Only the most important glass articles which can be produced from the melting furnace 14 with the glass melt or glass mass are mentioned below.

Building glass: wire glass, glass brick, window glass, profiled glass, foam glass.

Laboratory glass: Bulkhead glass with special resistance to attack by chemical reagents: Si0 ₂ 74.5% by weight, B ₂ ° ₃ ⁴ '**% by weight, BaO 3.9% by weight, CaO 0.8% by weight, A1 ₂ 0 ₃ 8.5% by weight, MgO 0.1% by weight, Na ₂ 0 7.7% by weight. or from Pyrex: Si0 ₂ 80.5% by weight, ^B ₂ ° 3 11.8% by weight, A1 ₂ 0 ₃ 2.0% by weight, Na ₂ 0 4.4% by weight.

X-ray protective glass with a high lead content.

Protective neutron absorbing glass with 35% cadmium oxide.

Insulating materials: foam glass interspersed with numerous air bubbles, glass insulators, glass wool.

REPLACEMENT LEAF Colored glasses: by adding metal oxides and metal sulfides, oxides of chromium, iron, copper, manganese, nickel, sulfides of iron. These additives create the different colors in the glass. This also includes paint carriers in facade elements and plasters for the exterior walls of buildings exposed to wind and weather.

Lead crystal: with at least 24% lead.

Phosphate glass: contains instead of SiO phosphorus oxide and is resistant to hydrofluoric acid.

As granules: in various colors as an additive for mortar, plaster and concrete, it should be emphasized that these granules are suitable for building objects that are intended to protect against X-rays or radioactive rays. Such granules must have a high proportion of lead compounds. Furthermore, the granules are used as filling material for filling up disused gravel pits, disused mines, road construction, etc.

As a coating material: on metal (reinforcing iron for concrete, pipes and containers), ceramics (brick or Dachpfannen¬ glazes, tiles, chimney elements), glass, natural stones or marble. In many cases, the coating material is also a protective material against corrosion.

The right melt is already available for the glass articles mentioned because of the chemical elements and compounds of the filter dust, sludge and waste glass.

The electronic control circuit 17 contains an input circuit 171 which receives the signals from the sensors, an output circuit 172 which gives the commands to the individual devices, a programming unit 173 and a microprocessor 174. Since the signals from the sensors are analogous to Given input circuit 170 and the microprocessor 174 only processes digital signals, analog / digital converters are provided in the input circuit 171. Furthermore, this circuit has an interrogation circuit which switches the sensors in a specific time sequence of e.g. 1 sec. So that many sensors can be connected to one line. Hang in Figure 1

REPLACEMENT LEAF the sensors with the same detection tasks on one line. The output circuit 172, which gives the command signals in analog form to the individual devices of the entire system and receives only digital signals from the microprocessor 174, contains digital / analog converters and an interrogation circuit which, in a specific time sequence of, for example, 1 second Command signals to the assigned devices. This is made possible by the fact that each command signal contains an address for the device in question. This allows several devices to hang on a connecting line. The programming unit 173 contains slots for programmable read-only memories (PROM). Each of these fixed memories contains the program for a specific mixing ratio between filter dust and waste glass or sludge and waste glass or several components. The program also contains data for the weight and shape of the blanks 131 produced in the compactor 12, for the timing at which the blanks are moved into the melting furnace 14, for the temperature control in the melting furnace, for the viscosity in the melting furnace, for further processing in the device 16. The program also specifies when no blanks are to be pressed, ie when the mixing device 121 conveys the mixture directly onto the slide 13. The fixed memory that is to control the operation of the entire system is activated, ie it is inserted in the slot of the programming device 173. If another program for the operational control - that is to say another fixed memory - is desirable, this can be activated without further ado. The previous permanent memory is deactivated at the same time. Furthermore, the data in the program are determined by the glass article for which the glass melt is to be used and the chemical composition of the filter dust or the sludge. The chemical composition is normally the same. If there is an exceptional change in the chemical composition, the program can easily be changed accordingly. This is done by means of a keyboard which is arranged in the programming unit 173. An authorized person enters the numerical code for the changed composition in the programmable fixed memory. The microprocessor 174 processes the digital signals of the input circuit 171 as actual values and generates under

REPLACEMENT LEAF Taking into account the specifications from the programming unit 173, the digital command signals for the output circuit 172, which gives the analog signals as SET values to the relevant devices.

The sensors 111, 112, 211, 212, 311, 312, 411, 412, 511, 512 detect the filling level in the silos 1, 2, 3, 4, 5. The sensors, which e.g. are designed as light barriers, report via line 175 to the input circuit 171 as soon as they are no longer covered by the material. In this case, new material is conveyed into the silo via the conveyor belt until the upper sensor 111, 211, 311, 411, 511 is covered again. This is controlled by the control system 17. In order to maintain the clarity of Figure 1, the corresponding conveyor belts with their lines have not been shown. Each of the sensors 113, 213, 313, 413, 513 only responds when the corresponding metering device 6, 7, 8, 9, 10 is in operation and the sensor, e.g. is designed as a light barrier, is not covered by the material. This means that the material forms a bridge in the lower part of the silo and cannot slip through to the metering device. The sensor of the silo in question sends the signal via line 175 to input circuit 171. Microprocessor 174 sends a digital signal to output circuit 172. From there, an analog control signal is sent via line 176 to the vibration device of the silo in question. This signal sets the vibration device into operation until the sensor is again covered with material that falls into the metering device. For reasons of a better overview, the vibration devices 61, 71, 81, 91, 101 in FIG. 1, which are known for bulk goods, are only indicated symbolically above the metering devices.

The dosing devices are controlled in accordance with the mixing ratio in the programming part 173 and the desired mixing components by means of a microprocessor 174, output circuit 172 via line 176 and put into operation until the desired mixing ratio is reached, which is indicated by corresponding sensors in the dosing devices via line 176 is reported to the input circuit 171. The mixer

REPLACEMENT LEAF 121, which is arranged, for example, in the compactor 12 and runs continuously, mixes the components transported via the conveyor belts 11 and passes the mixture on to the weighing and portioning device 123. This device makes portions with the weight predetermined by the programming unit 173 . This weight is communicated to the weighing and portioning device via microprocessor 174, output circuit 172, line 177. When the weight is reached, which is communicated to the input circuit 171 via line 124, the mixture portion reaches the pressing device 123 and is pressed there to a spherical or briquette-like blank 131. The control is also carried out by the program via the microprocessor 174, output circuit 172, line 177. The blanks arranged one behind the other in the output of the compactor are brought into the melting furnace 14 at predetermined time intervals via slide 13, which is done via the same line tion 177 is controlled. The other line 124 sends a signal to the input circuit 171 for each blank which is brought onto the slide. The output circuit 172 outputs a signal for opening the door 141 via line 178, so that the blank 131 on the slide 13 is sufficiently unimpeded can reach far into the melting furnace 14.

The temperature control in the melting furnace 14 and the permanent monitoring of the viscosity of the melt 18 take place via line 142 for the actual values, which are given as analog signals in the input circuit 171, and via line 179 for the target values, the are given as analog signals in the heating and the viscosity sensor. Programming unit 173 and microprocessor 174 are also involved in this action.

The further processing of the glass melt or the solidified glass mass in the region 16 is also controlled electronically. This is shown by lines 161, 180. This further processing can be a wide variety of processes such as blowing, pressing, rolling, granulating, drawing, as has been described in more detail above.

Figure 2 shows the bottom 20 of a trough-shaped melting furnace 14. In the bottom, the meandering groove 21 is provided, in which the glass melt 18 flows. The gutter thus formed contains many

REPLACEMENT LEAF Baffles so that the melt mixes well. The glass melt has a thickness of approx. 2 cm to 100 cm and remains in the melting furnace for about 15 to 125 minutes until it reaches the exit. The groove 21 has a helix angle of 5 to 10. The melt viscosity sensor, which sends its signals to the input circuit 171 via line 142, is arranged in the upper third of the furnace. It consists, for example, of a rod made of refractory material which executes circular movements in the melt. It is moved at a constant speed. If the melt becomes viscous (high viscosity), the torque required to rotate the rod increases. The analog signal changed in this way causes in the electronic control 17 that flow promoters from silo 5 get into the melt. This furnace is heated with a flashover, the majority of which is directed towards the channel 21. Oil and gas can be used as fuels. In the case of electric heating, heating elements are arranged a few centimeters above the melting channel 21.

FIG. 3 shows the trough-shaped melting furnace in the representation of the section lines A - A, from which the inclination of the channel 21 emerges.

FIG. 4 shows the melting furnace 14 as a rotary furnace in a side view. The rotary kiln is mounted on rollers so that the inlet with the groove 13 is 5 degrees higher than the outlet with the chute 15. A motor 25 rotates the cylinder of the rotary kiln via a gear and gear wheels 22 which mesh with ring gears of about 5m / minute. The bricked-up cylinder 24 has a diameter between 2 m and 5 m and a length of up to max. 50 m. The heating is done with gas or oil. The flame nozzles are located at the lower end and do not rotate, so that the flames and the hot gases can flow over the melting material to the upper end. The actual melting takes place in the lower part of the rotating cylinder.

FIG. 5 shows a sectional illustration according to the section lines B - B of FIG. 4. The gearwheels 22 with the cylinder including the lining 24 with refractory material can be seen therefrom.

REPLACEMENT LEAF FIG. 6 shows the melting furnace 14 as a shaft furnace, which consists of a sheet steel jacket 30 with a refractory lining. By ^'opening 32, coal is first filled in the well and subsequently ignited. It is advisable to use coke, since it contains enough large pieces that wedge in the shaft. Then the briquette-shaped blanks 131 are transported into the shaft. In the shaft furnace, only the briquette-shaped blanks are filled in via the groove 13. Coke and blanks are now transported into the shaft together. Wind blows through openings 33 and increases the heat of the coke. The exhaust gases pass through exhaust 37 into a device for flue gas cleaning, which contains electrostatic filters. This device is not shown since it is generally known. The blanks lying between the coke, which also contribute to the wedging, disintegrate and are melted the deeper they travel. Coke slag and melt reach the refractory bevel 34 and migrate to the grate 36. The melt flows through the coke slag onto the channel 15, which conveys the glass melt into the further processing 16. The coke slag is removed via chute 35. The shaft furnace is designed for continuous operation. It should also be pointed out that the mixture of waste glass, filter dust or sludge is melted at a lower temperature of 800 ° C. to 1200 ° C. and therefore less volatile chlorides escape through the hood 37 than at higher temperatures of 1400 ° C. and more. With the exception of a small proportion of the mercury, the heavy metals remain in the melt. The electrostatic filters for the flue gas cleaning of the shaft furnace only have to retain little toxic substances. The filter dusts resulting from periodic washing of the electrostatic filters are brought into the silo 1.

FIG. 7 shows the eutectic temperatures in a three-substance system Na ₂ 0 - Si0 ₂ = curve NS; K ₂ 0 - Si0 ₂ = curve KS; Li-0 - SiO- = curve LS. The eutectic temperatures, which are indicated by horizontal lines, occur at certain mixing ratios. You can see that the eutectic temperatures are the lowest for a system. Since the old glass from silo 4 consists, among other things, of these systems with different mixing ratios of the system components,

REPLACEMENT LEAF an increased addition of the old glass favorably affects the melt in the melting furnace. This means that the melt is melted at the most favorable eutectic temperature. In practice, the eutectic of the glass melt levels off due to the different components in the waste glass. Some systems are listed below with their eutectic temperatures:

304 ° C approx. 600 ° C 680 ° C 685 ° C 690 ° C 710 ° C 712 ° C 740 ° C 755 ° C 800 ° C

REPLACEMENT BUTT

Claims

PATENT CLAIMS 1. Process for the safe disposal of toxic residues which arise during the removal of solid waste and during chemical processes, the residues being formed as filter dusts which are produced in the flue gas cleaning of incineration plants for solid waste and as sludges or solutions are, which arise during the course of chemical processes, characterized ¬ characterized in that the filter dust and / or the sludge, including the solutions with crushed waste glass, are mixed in a mixing ratio, and the mixture is subjected to a heat treatment at a certain temperature to form it a homogeneous glass melt (18) which is chemically inert at normal temperature, the transition of heavy metals and their chlorides into the gas phase being reduced during the heat treatment. 2. The method according to claim 1, characterized in that the filter dusts and / or the sludges, including their solutions, are mixed with a waste glass in a specific mixing ratio of 100: 1 to 1: 100 and a heat treatment of 700 ° C is subjected to up to 1200 ° C. to form a homogeneous glass melt (18) which is chemically inert at normal temperature, the transition of heavy metals and their chlorides into the gas phase being reduced during the heat treatment. REPLACEMENT BUTT 3. The method according to claim 1, characterized in that the mixture of the filter dusts and / or the sludges, including their solutions, is formed with the grain size of 6 mm old glass into a three-dimensional shape body (131) and the heat treatment subjected in the temperature range from 700 ° C to 1500 ° C to form a homogeneous glass melt (18) which is chemically inert at normal temperature, during which the transition of heavy metals and their chlorides into the gas phase is reduced during the heat treatment. 4. The method according to claims 1 or 3, dadurchge ¬ indicates that the filter dusts and / or slurries, which are present as solutions or suspensions, are mixed with the crushed waste glass in a preferred mixture ratio of 1: 5 to 2: 1 The waste glass contains chemical compounds which reduce the transition of chlorides, heavy metals and heavy metal chlorides from the melt (18) into the gas phase during the heat treatment and reduce the temperatures of the heat treatment. 5. The method according to claims 1 or 3, dadurchge ¬ indicates that the filter dust with a grain size of 1-6 microns and / or the sludges, which are present as solutions or suspensions, are mixed with the shredded waste glass, wherein NaOH is added to the mixture in a certain ratio, which NaOH reduces the formation of chlorides, especially heavy metal chlorides, which occur during the heat treatment, and their transition from the melt (18) into the gas phase. 6. The method according to any one of claims 3, 4, 5, characterized in that the filter dust and / or sludge mixed with the crushed waste glass are divided into portions with a certain weight, each portion being of a certain three-dimensional shape ( 131) is pressed, and the thus shaped REPLACEMENT BUTT Portions in a melting furnace (14) are subjected to the heat treatment in order to form a homogeneous melt (18) which is chemically inert at room temperature, which melt is further processed into commodities, granules, flour and decorative objects. 7. Device for performing the method according to one of the preceding claims, characterized in that silos (1, 2, 3, 4) for the storage of the filter dust, lead waste, chemical sludge, the crushed waste glass and a silo (5) for flow promoters to improve the flow properties of the melt (18) are provided, each silo containing a metering device (6, 7, 8, 9, 10) for metering the amount of the material stored in the silo required for the predetermined mixing ratio, which metered amount is obtained in a mixing device (21) and mixed with a metered amount of at least one other material required for the mixture and melted in a melting furnace (14) to form a homogeneous and chemically inert melt (18) which is in a device ¬ device (16) is processed into commodities, granules, flour and decorative objects. 8. The device according to claim 7, characterized in that silos (1, 2, 3, 4) for storing the filter dust, lead waste chemical sludge, the crushed old glass and a silo (5) for flow promoters to improve the flow properties of the Melt (18) are provided, each silo containing a metering device (6, 7, 8, 9, 10) for metering the amount of material stored in the silo required for the predetermined mixing ratio, the metered amount into a mixing device ( 121) is obtained and mixed with a metered amount of at least one other material required for the mixture, and the mixture is brought into a weighing and portioning device (122) in which portions are weighed with a certain weight, and each portion in a subsequent press (123) to form a three-dimensional body (131) REPLACEMENT BUTT a particular shape is pressed, which bodies are melted in a melting furnace (14) to form a homogeneous and chemically inert melt (18), which is further processed in a device (16) to produce commodities, granules, flours and decorative objects. 9. The device according to claim 7 or 8, dadurchge ¬ indicates that each silo (1, 2, 3, 4, 5) sensors (111, 112, 211, 212, 311, 312, 411, 412, 511, 512) contains which detect the degree of filling in the silo and supply a status signal via line (175) to an input circuit (171) of an electronic control circuit (17), which control circuit causes the filling of that silo via a microprocessor (174) and output circuit (172) that contains too little material. 10. The device according to claim 7 or 8, so that a sensor (113, 213, 313, 413, 513) is provided in the output of each silo (1, 2, 3, 4, 5). can be seen that detects the passage of the material stored in the silo in the direction of the metering device (6, 7, 8, 9, 10) and, if there is no or interrupted material passage, a signal via line (175) into the input circuit (171) of the electronic Control circuit (17), in which the signal is processed in a microprocessor (174) taking into account the programming unit (173), generates a control signal and is sent to the output circuit (172) which control signal is transmitted via line ( 176) starts a vibration device (61, 71, 81, 91, 101) arranged at the exit of the silo until the material has free passage again. 11. The device according to claim 7 or 8, dadurchge ¬ indicates that the mixing device (121) contains a sensor that monitors the degree of filling of the mixing device and a signal via line (124) in the input circuit (171) of the electronic control circuit (17) are given, the microprocessor (174) if the mixing device (121) is filled too little or not with the aid of the program REPLACEMENT BUTT Mier unit (173) gives a control signal via output circuit (172), line (176) to the metering devices in operation and, if appropriate, to the corresponding vibrating devices, and a further control signal via output circuit (172), line (177) to the mixing device (121) to put it out of operation until the prescribed filling level is reached again. 12. The apparatus of claim 8, d a d u r c h g e k e n n ¬ z e i c h n e t that the weighing and portioning (122) in the compactor (12) makes the mixture portion so large until the weight is reached, which was predetermined by a programming unit (173) arranged in the electronic control circuit (17), which is done via line (124), input ¬ circuit (171), microprocessor (174), output circuit (172) and line (177) is controlled and monitored. 13. The apparatus of claim 8, d a d u r c h g e k e n n ¬ z e i c h n e t that the pressing device (123) provided in the compactor (12) forms the mixture portion brought to the specific weight into a ball or a briquette. 14. The apparatus of claim 7 or 8, d a d u r c h g e ¬ k e n n e e c h e n t that a sensor for the detection of the viscosity of the melt is provided in the melting furnace (14), which the signals via line (142) in the input circuit (171) indicates which signals are processed in the downstream microprocessor (174) taking into account the programming unit (173) into control signals which are output (172) and line (176) put the dosing device (10) of the silo (5) into operation with the flow promoters, so that the blanks pressed thereafter are enriched with these flow promoters, which improve the flow properties of the melt (18). REPLACEMENT BUTT