WO2002036834A2 - Method and apparatus for utilising recyclings containing iron and heavy metals while involving the use of a melting cyclone, a separating vessel, and a vessel for carrying out metallurgical treatment - Google Patents

Abstract

According to a method for utilising solid, optionally with the addition of iron ore, the recyclings are introduced into a melting cyclone (6), together with a reduction agent containing carbon, and oxygen, swirled and ignited. The recyclings are melted, the volatile heavy metals are reduced and evaporated and the iron oxides are reduced. The gases and melt are transferred together from the melting cyclone (6) to a directly connected separating vessel (7) in which the melt and gases are separated. The evaporated heavy metals are separated out of the gases outside of the separating vessel (7) and the melt is transferred into a metallurgical vessel (10) that is separate from the separating vessel (7). According to the invention, reduction agents which are fed into the metallurgical vessel (10) reduce the iron oxides of the melt to iron, whereby a slag that is low in iron is formed, while electrical energy is introduced to at least partially cover the heat loss and the reduction energy, in order to transform 100 % of the recyclings containing iron and heavy metals into useful products.

Description

Process and plant for recycling iron and heavy metal residues, if necessary with the addition of iron ore

The invention relates to a method for recycling iron and heavy metal-containing residues, optionally with the addition of iron ore, the residues together with reducing agents such as coal and / or coke and / or carbon-containing and / or hydrocarbon-containing residues and / or hydrocarbons in solid and / or liquid and / or gaseous form, as well as oxygen and / or oxygen-enriched air are introduced into a melting cyclone, swirled and ignited, the residues are melted, volatile heavy metals are reduced and evaporated, iron oxides are reduced, the gases and the melt from the melting cyclone together are transferred into a directly coupled separating vessel in which the melt and gases are separated, the evaporated heavy metals are separated from the gases outside the separating vessel and the melt is transferred to a metallurgical vessel separated from the separating vessel rt is, as well as a plant for performing the method.

A major problem of the iron and steel producing industry lies in the large quantities of iron and heavy metal-containing residues, such as furnace dust, sludge, mill scale and the like, which are only accessible for recycling with great effort and are therefore usually landfilled without being dumped to take advantage of their valuable content.

From an ecological and economic point of view, there is a need to convert the residues as completely as possible into usable products and thus avoid waste that would otherwise have to be disposed of. Technically and economically usable products into which the residues can be transferred are metallic iron, low-iron slag, which can be used in cement production, and a concentrate of volatile heavy metals in the form of the oxides of zinc, lead and cadmium. In addition, the greatest possible use of process waste heat is ecologically desirable.

In a process described in DE-A-44 39 939, residues are melted in a melting cyclone, the heavy metals are evaporated and separated from the exhaust gas after oxidation as a dust fraction. The remaining slag is further depleted of heavy metals in a sub-furnace by blowing up reducing gas and oxygen and subsequently as a raw material for cement or rock wool production used. In this process, however, iron oxides are not reduced to metallic iron, which means that an essential part of the residues remains unused.

A device for reducing and smelting iron ore is described in EP-A-0 735 146. According to EP-A-0 735 146, iron ore is reduced and melted in a melting cyclone and enters a metallurgical vessel immediately below the melting cyclone, in which the final reduction takes place with the formation of a process gas from coal and oxygen blown onto the slag / metal layer and the complete melting of the iron takes place. The reducing process gas is partially burned with oxygen and in this way provides the heat necessary for the melt and the reduction both in the melting vessel and in the melting cyclone. The exhaust gases are drawn off at the top opening of the melting cyclone.

A recycling of heavy metal-containing residues would not be possible according to this method, since all the exhaust gases are drawn off at the upper opening of the melting cyclone, which affects the swirling of the material in the melting cyclone and thus a complete evaporation of the heavy metals would no longer be guaranteed. In addition, the afterburning of the exhaust gases would result in heavy metals being oxidized again to solid heavy metal oxides already in the melting cyclone and therefore being largely separated out again in the melting cyclone.

A method of the type mentioned is described in DE 35 36 635 A. According to this method, the residues are melted in a melting cyclone under reducing conditions. The evaporated heavy metals are separated from the gas and the slag is placed in a steel converter on the pig iron present, iron oxide from the slag being reduced to iron with the carbon present in the pig iron.

However, this method has several disadvantages. The use of slag is limited to about 50 kg / t of pig iron due to the small amount of carbon in the pig iron, otherwise the productivity of the steel converter would be significantly reduced. The reduction potential of pig iron is not sufficient for larger quantities of slag containing iron oxide. The liquid charging of such small amounts of slag leads to disruptions in the production process on the converter, in particular due to the additional crane operations, and thus also to a reduction in productivity. Another problem is the undesirable accompanying substances contained in the slag, such as sulfur and phosphorus, which lead to a reduction in the quality of the steel produced in the steel converter. The yield iron from the slag is also insufficient since the remaining steelworks slag usually has an iron oxide content of 20% to 30%. Due to the high iron oxide content, this slag cannot be recycled in the cement industry.

A process for the recovery of iron and heavy metals such as zinc and lead from residues of the steel industry is described in AT 407 878 B. In this process, the heavy metal-containing gas, the partially reduced iron and the slag are transferred to a furnace which is directly coupled to the melting cyclone and into which reducing agent and oxygen are blown in to reduce the iron. The energy required for the reduction is fed into the furnace via a direct arc. According to this process, the heavy metal-containing gas is burned outside the furnace and the heavy metal oxides that form are separated off.

Due to the direct coupling of the furnace with the melting cyclone, it is not possible to obtain the various products in the form required for further processing, in particular with a consistently high quality. The exact setting of a certain iron analysis or a certain temperature of the molten iron cannot be accomplished. Furthermore, it is also not possible to set a slag composition with an iron content of less than 2%, which is required for use in cement production.

The quality of the heavy metal product produced also suffers from the direct coupling of the melting cyclone to the furnace in which the reduction to iron takes place, since the reduction releases larger amounts of dust, which are precipitated from the melting cyclone together with the heavy metals of the heavy metal-containing gas. In addition, the process control is made considerably more difficult by coordinating the reactions taking place simultaneously in the melting cyclone, in the furnace and in its flue pipe.

The invention has as its object to further develop the method known from the Austrian application A 865/99 and the known system in such a way that residues containing iron and heavy metals, if appropriate with the addition of iron ore, are 100% converted into usable products of constant high quality and No further waste arises, and in contrast to the known method, simple process control and reliable operation of the system should be possible. In particular, an exact setting of the analysis and the temperature of the iron melt as well as the generation of a slag with an iron content of less than 2%, which can be used in cement production, should be made possible become. Furthermore, the quality of the heavy metal product produced is to be improved. Compared to competing processes, this should result in savings in operating costs.

This object is achieved in that on the one hand reducing agents are fed into the metallurgical vessel, the iron oxides of the melt are reduced to iron to form a low-iron slag and on the other hand electrical energy is introduced to at least partially cover the heat losses and the reduction energy.

Since the separating vessel only separates the melt and gases, but does not yet treat the products obtained in the cyclone, the subsequent process steps, namely the reduction of iron, the separation of heavy metals from the gases and the adjustment of iron and slag quality, become complete independently of each other and can therefore be carried out in an optimal manner regardless of each other. This leads to a better quality of the molten iron, the slag and the heavy metal product and results in a significantly simpler process control and monitoring.

The evaporated heavy metals are preferably separated from the other gases by post-burning the gases immediately after exiting the separation vessel by means of air or oxygen-enriched air, and in this process converting the heavy metals into a solid oxidic form and then separating them from the gases. The separating device is preferably designed as a bag filter unit. The separated metal oxide, for example ZnO, can be used as a starting product for zinc production.

In order to make the process more economical, the gases are advantageously cooled in a heat exchanger after the afterburning with the generation of steam.

In a further variant, the gases are quenched directly at the outlet from the separation vessel by means of water, the heavy metals are condensed and separated by means of a wet dust separation process, such as, for example, venturi scrubbers or wet electrostatic precipitators. In the aqueous phase, the heavy metals oxidize to oxides, which are then separated off. The cleaned gases, among which there are flammable gases such as carbon monoxide and hydrogen, are then used, for example, for combustion to generate energy. For the direct reduction of the iron, which is predominantly present as FeO in the melt, coke and / or coal and / or carbon-containing and / or hydrocarbon-containing residues are introduced into the metallurgical vessel, preferably blown in, as carbon-containing reducing agents. For this purpose, the metallurgical vessel is equipped with at least one lance and / or nozzle for blowing in reducing agent.

In the case of the desired transfer of non-volatile heavy metals, which cannot or only partially be reduced when carbon-containing reducing agents are added, a stronger reducing agent, for example ferrosilicon or aluminum, is introduced into the metallurgical vessel for further reduction. This is generally used after the reduction with carbon-containing reducing agents.

Furthermore, a part of the iron oxides to be reduced is preferably reduced by means of carbon monoxide formed during the reduction of iron oxide with a carbon-containing reducing agent.

The energy required to reduce and cover the heat losses is largely brought in by the electrical energy. This is particularly advantageous since chemical energy introduced in the form of carbon or hydrocarbon can only be partially used because, because of the iron reduction required, combustion is only possible up to a certain CO / CO ₂ ratio. The electrical energy is preferably introduced via graphite electrodes.

In a further variant, the electrical energy is introduced inductively.

Advantageously, the gases formed in the reduction of the metal oxides present in the melt, essentially CO, which is also partly used for the reduction, are partially post-combusted by means of oxygen or oxygen-enriched air in the upper region of the metallurgical vessel. The partial post-combustion of CO to CO ₂ provides part of the energy required to cover the heat losses and to reduce it.

Another embodiment of the method according to the invention is characterized in that the energy required is partly introduced by means of a burner provided in the metallurgical vessel. The melt is advantageously stirred during the reduction and or during the introduction of energy, preferably by rinsing the floor. For this purpose, the metallurgical vessel is equipped with a device for stirring, for example floor washing elements or other stirring devices known to the person skilled in the art.

The iron melt is preferably conditioned by heating it to a temperature suitable for a subsequent casting process, preferably by means of electrical energy. A desired composition of the molten iron is advantageously set by adding alloy substances.

In a preferred embodiment, the gases produced in the metallurgical vessel are suctioned off and cleaned, the separated dust preferably being fed to the melting cyclone as a residue, since the dust contains iron components and also heavy metals.

The slag and the iron melt are expediently poured off separately.

In the metallurgical vessel, after the slag and the iron melt have been poured off, a metal melt sump is expediently retained and used in the metallurgical vessel as a template with a high carbon content and high temperature for a new batch of melt. The heat capacity of the residual melt and its carbon content make the process more uniform or the first reduction step of the new batch can be carried out until a certain minimum temperature and a very low carbon content are reached again.

This sump is advantageously covered with a certain amount of low-iron slag, which is preferably formed from fly ash, foundry sand and coke and / or coal, and the sump and slag are then used in the metallurgical vessel as a template for a new batch of melt. This acidic starting slag brings about a considerable reduction in the melting temperature of the slag resulting after the reduction, so that the reduction can be carried out down to relatively low temperatures.

According to a preferred embodiment of the method, the reduction of the melt on the one hand and the conditioning on the other hand are carried out at separate locations, a transportable metallurgical vessel being used. This makes the control of the process steps even clearer and easier. In another variant, the Reduction of the melt and the introduction of electrical energy are carried out at separate locations, using a transportable metallurgical vessel.

Another advantage of the separate steps is that the process can be carried out semi-continuously, i.e. that the previous batch can be conditioned during the melt reduction phase of a batch. In this preferred embodiment, at least two metallurgical vessels, preferably pans, are used.

The melt is preferably in the time in which no melt can be fed into the transportable metallurgical vessel, in particular if the metallurgical vessel for pouring and / or conditioning the melt and / or for introducing the electrical energy is at another location Separation vessel temporarily stored.

Alternatively, the melt between the deposition vessel and the transportable metallurgical vessel is temporarily stored in a stationary storage device for bridging process interruptions, such as heating periods, vessel changes, etc. For this purpose, a storage device for the melt in the form of a tilting channel is advantageously provided subsequent to the outlet opening of the separating vessel. This is expediently lined with refractory material and / or equipped with a burner to cover heat losses.

The iron and heavy metal-containing residues are advantageously collected separately in heavy metal and low heavy metal residues and used separately in the melting cyclone, and heavy metals separated from the gases are fed to the heavy metal-rich residues when low-heavy metal residues are used.

In another embodiment, the heavy metals separated from the gases are collected and used again in the melting cyclone up to an enrichment of the heavy metals desired for the removal, in particular regulated with continuous measurement of one or more heavy metal concentrations in the separated dust.

The heat losses from the melting cyclone and / or the separating vessel are preferably used to generate steam. For this purpose, the melting cyclone and / or the separation vessel are expediently equipped with a cooling device, such as an evaporative cooling device. In a further preferred embodiment, the slag is allowed to solidify in a suitable manner after pouring, for example by means of a casting bed or dry granulation, and is used as a feedstock for cement production, for example as a clinker.

A plant according to the invention for recycling iron and heavy metal-containing residues, optionally with the addition of iron ore, is characterized by the combination of the following features: an essentially vertical melting cyclone, which has a bottom opening for the escape of gases and melt, one or more opening into the melting cyclone , essentially horizontal feeds for solid feed materials and for gases and a

Ignition device, a separating vessel directly coupled to the melting cyclone, which has a

Has opening for the exit of gases and a second opening for the exit of the melt, an exhaust pipe, which starts from the exhaust opening of the separating vessel and to a device for separating the heavy metals from the

Separating vessel escaping gases leads to at least one metallurgical vessel, which has at least one device for

Supply of reducing agent and at least one device for pouring

Has molten iron and slag, a device for transferring the melt from the melt outlet opening of the separating vessel into the metallurgical vessel and a device for electrical heating of the metallurgical vessel.

Preferably, the exhaust pipe starting from the separation vessel is equipped with an opening for the supply of air or oxygen-enriched air. The opening is preferably designed in the form of a sliding sleeve.

Furthermore, a device for blowing oxygen into the metallurgical vessel is preferably provided in order to afterburn the gases produced during the reduction.

The metallurgical vessel is advantageously equipped with a sufficiently large volume so that there is still enough space above the metal sump from the previous batch, the metal from the reduction and the resulting slag for the reduction reaction associated with foams. In a preferred embodiment, the device for electrical heating is designed in the form of graphite electrodes or an inductive heating.

In a further preferred embodiment, the metallurgical vessel is designed as a transportable vessel, in particular as a pan.

A transport device for moving the (r) metallurgical vessel (s) is advantageously provided.

Feeding devices are expediently provided for feeding lumpy and / or fine-grained materials into the metallurgical vessel, for example for fly ash, fine coal, etc.

A heat exchanger, in particular a steam boiler, is preferably provided in the exhaust pipe starting from the separating vessel.

The invention is explained in more detail below with reference to the drawing, the figure illustrating an embodiment of the system according to the invention or of the method in block diagram.

In order to obtain residues with the properties required for use in the melting cyclone, these are subjected to a pretreatment. The iron and heavy metal-containing residues, especially the sludge, are dried, with the oil-containing sludge being treated separately. It is also possible to separate the residual materials into those that are rich and low in heavy metals. This has the advantage, among other things, that when heavy residues rich in heavy metals are used, a heavy metal concentrate which is suitable for further processing is obtained even when the process according to the invention is carried out once.

The oily sludges, which usually have high proportions of organic components and therefore cannot be dried directly like the other residues, are premixed, for example, and charged into the feed container. From there, the sludge is metered via a feed system into a mixing and drying device 1, in which the charged material is dried indirectly by means of a thermal oil system. The thermal oil generator is heated, for example, with natural gas burners. The exhaust gas from the dryer is used as combustion air so that no hydrocarbons are released. The dried sludge is charged into a buffer tank and from there into the corresponding storage bunker. The remaining sludges are dried in a continuously operating dryer 2 by means of a hot wind to the moisture content suitable for blowing into the melting cyclone. The final moisture of the product is controlled via the exhaust gas temperature, which is directly proportional to the product moisture. The exhaust gas from the dryer is roughly dedusted in a cyclone and fine in a bag filter. The dried material is crushed and charged in a storage bunker.

Other residues and / or reducing agents, such as mill scale or coal, are comminuted or ground in suitable devices 3 to a size that is acceptable for blowing into the melting cyclone, and then stored in a corresponding silo.

Dusts are conveyed pneumatically into storage silos without pretreatment, from where they are continuously removed in order to be mixed with the other residues and, if slag formers are not sufficiently contained in the residues, additives in appropriate proportions. However, the addition of additives should be avoided as far as possible by selecting an appropriate mixture of various residues containing sufficient slag formers.

The feed materials, residues, reducing agents and additives, which should all be essentially water-free, are continuously introduced in the appropriate amounts into an intensive mixer 4 and homogenized. From the mixer 4, the mixture of substances reaches a coarse sieve 5, where particles larger than 4 mm are removed from the mixture. The sieved mixture is stored in storage silos, preferably separately for residues rich and low in heavy metals.

Using pneumatic systems, the precisely weighed solid mixture with oxygen or oxygen-enriched air is essentially tangentially blown into the essentially vertical, cylindrical melting cyclone 6, swirled and ignited by a burner fed with oxygen and a gaseous fuel, which is integrated in the cyclone burner. In addition to the auxiliary burner intended for ignition, the cyclone burner has a fire control system, a flame detection system and a monitoring system. A plurality of burners can also be provided at different points in the melting cyclone 6. Inside the melting cyclone 6, there is a reduction of the iron oxides and volatile heavy metals contained in the residues and, if appropriate, of iron ore, iron oxides predominantly being reduced to FeO and the volatile heavy metals to the metal. Evaporation of the volatile heavy metals, partial oxidation and / or gasification of the carbon- and / or hydrocarbon-containing reducing agents and melting of the other solid fractions of the starting materials are also brought about by the reaction conditions and high temperatures prevailing in the melting cyclone 6.

From the melting cyclone 6, the gases and the melt pass together into a directly coupled, i.e. Separation vessel 7 connected only via a suitable connecting piece, preferably arranged below the melting cyclone 6 - to clarify the apparatus unit, the melting cyclone 6 and the separation vessel 7 are provided with a dashed border in the figure - in which a separation of the melt and gases takes place. The separating vessel is designed, for example, as a cylindrical vessel with a horizontal axis, which has an opening for the exit of gases and a second opening for the exit of the melt.

The separating vessel can, however, also be designed as a container which is at least partially bricked or lined with refractory material, in particular as a cylindrical container with a vertical axis or as a rectangular container.

Both the separating vessel 7 and the melting cyclone 6 are preferably equipped with a cooling device, for example in the form of a water-cooled double jacket construction or a steam-cooled pipe-pipe or pipe-web-pipe construction, in order to use their heat losses to generate superheated steam. The cooling system is fed with boiler feed water or its circulating condensate.

The gases containing heavy metals, including carbon monoxide and hydrogen, are afterburned after they exit the separation vessel by means of air or oxygen-enriched air, which is blown in through an opening in the exhaust pipe, for example in the form of a sliding sleeve. The evaporated heavy metals are converted into a solid oxidic form and form a fine dust in the gases. After the afterburning, the gases are preferably passed through a heat exchanger 8, for example a steam boiler, and cooled for the purpose of generating steam, a portion of the heavy metal dust being separated off. In order to keep the heating surfaces of the heat exchanger clean from separated dusts, automatic cleaning devices can be provided as well a device that removes the heavy metal dust from the cooling device and transports it to the corresponding silo, depending on whether the dust comes from heavy metal rich or low in residual materials.

The cooled gases are cooled further by admixing ambient air in order to obtain the filter 9, e.g. Bag filter to reach the required inlet temperature, where the heavy metal oxides are finally separated. The cleaned gases are released into the atmosphere. If the residues are collected and used separately in heavy and low-heavy metals, the separated heavy metal oxide dust from low-heavy residues is fed to the heavy-metal-rich residues. Alternatively, the separated dust can be reused as a residual material while continuously measuring the heavy metal concentration until a desired concentration of heavy metals has occurred.

Alternatively, the gases containing heavy metals can be quenched after condensing from the separating vessel 7, condensed and the heavy metal oxides formed in the process can be wet-separated.

The melt is transferred from the separation vessel 7 via a tapping channel into a metallurgical vessel 10. The vessel 10 is closed with a liftable and pivotable cooled lid provided with corresponding openings. The main reduction of iron oxides takes place in the metallurgical vessel, the resulting slag being low in iron. As a carbon-containing reducing agent for direct reduction, coke and / or coal and / or carbon-containing and / or hydrocarbon-containing residues, preferably fine coal, fine coke, carbon-containing dusts, tire shredders, plastic shredders, petroleum coke, etc., are used. In addition, the carbon dissolved in the metal is used.

If non-volatile heavy metals are contained in the residues, which cannot or only partially be reduced when carbon-containing reducing agents are added, a stronger reducing agent, for example ferrosilicon or aluminum, can be used alone or after the reduction with carbon-containing reducing agents, for economic reasons the second alternative is preferred.

The carbon monoxide formed in the direct reduction by reducing agents containing carbon and hydrocarbons can also be used to reduce the iron oxides. Fine-grain reducing agents are blown into the melt, for example, using refractory immersion lances or nozzles; however, a device for introducing lumpy materials into the metallurgical vessel 10 can also be provided.

A corresponding bath movement is advantageously generated by stirring devices, such as floor-flushing nozzles, both during the reduction period and during the heating period.

The gases produced during the reduction with carbon-containing reducing agents, predominantly CO, are advantageously afterburned with oxygen or oxygen-enriched air blown into the metallurgical vessel 10 in the upper region of the vessel 10 and thus improve the energy balance. The actual heating of the metallurgical vessel 10 takes place by means of electrical energy, which can in part also be generated with the help of the superheated steam obtained by cooling. The electrical energy can be introduced via electrodes or inductively, the device for heating the metallurgical vessel 10 in the case of a transportable metallurgical vessel also being able to be set up at another location independently of the vessel. It is thus possible to carry out the method semi-continuously with at least two transportable metallurgical vessels, the metallurgical vessels being transported to this device for intermediate or final heating.

The energy required for reducing and covering the heat losses is preferably introduced into the metallurgical vessel in part by means of a burner. The time required for heating a second metallurgical vessel can also be bridged more easily with the help of the burner.

The dust-laden gases formed during the reduction are sucked out of the metallurgical vessel and cooled and cleaned of dust by means of known devices 11, 12, for example similar to devices 8 and 9. The separated dust is used again in the melting cyclone as residual material, so that no waste that can be deposited is generated even in this process step.

If the process is carried out semi-continuously, two pans are preferably used as transportable metallurgical vessels 10, in which the melt is alternately reduced and conditioned or heated. In order to bridge the period of the vessel change, the melt is ^"temporarily stored in the separation vessel 7, which can be correspondingly large dimensions. Alternatively, between the separation vessel 7 and the transportable metallurgical vessel 10, a stationary storage device, for example a tipping channel equipped with refractory material and / or a burner, can be provided.

After the reduction of the iron oxides of the melt has been completed, there is an iron melt and a low-iron slag in the metallurgical vessel 10, both of which can be adjusted for further use. If the molten iron is intended for casting, it can be heated to a temperature suitable for this process by means of electrical heating. For other purposes, the molten iron is carburized, for example by adding coal, to a conventional pig iron analysis or adjusted to a desired composition by adding alloys.

After the conditioning, molten iron and slag are poured off separately from the metallurgical vessel 10. The poured-off, low-iron slag is solidified, for example, in casting beds or by means of a dry granulation system 13, comminuted and fed to the cement production.

A metal melt sump is retained in the metallurgical vessel 10, onto which new melt is poured out from the separation vessel 7. The heat capacity of this residual melt and its carbon content in the event of carburization of the iron melt can be used for the reduction treatment of the new melt, which results in a more even process. Preferably, the melting sump is still covered with a certain amount of low-iron slag, which is formed from fly ash, foundry sand and coke and / or coal, and then used as a template in the metallurgical vessel 10. As a result, the melt transferred from the separating vessel 7 into the metallurgical vessel 10 is diluted to a low iron content and the load on the vessel lining is thus considerably reduced. This also ensures a deep slag melting point.

By means of the method according to the invention, the products heavy metal concentrate, iron melt and slag are obtained in consistent quality as 100% recyclable substances, with no unusable waste being produced. In addition, steam is generated, which contributes to the economy of the process.

The process sequence according to the invention is illustrated with the aid of Examples 1 and 2 below, Example 1 illustrating the utilization of residues rich in heavy metals and Example 2 illustrating the utilization of residues low in heavy metals. The quantities In the following, each refer to a ton of residual material without reducing agents or supplements.

example 1

1000 kg / h of iron and heavy metal-containing residues, which had a composition shown in Table 1, and 10 NmVt of gaseous reducing agent were introduced into the melting cyclone and swirled and ignited with 250 Nm ³ / t of oxygen. The introduction of solid carbon-containing reducing agents was not necessary due to the high carbon content of the residues.

The resulting melt and the gases containing heavy metals were separated in the separating vessel. The melt was transferred to the metallurgical vessel and reduced with 70 kg / t coal. The electricity requirement of the device for heating the metallurgical vessel was 300 kWh / t. An iron melt and a slag with the compositions given in Table 2 were obtained.

The CO-containing gases were afterburned with 30 Nm ³ / t oxygen in the upper area of the metallurgical vessel.

50 kg / t of used foundry sand and fly ash were introduced into the metallurgical vessel to build up a slag feed on the retained melt sump.

A heavy metal product with a composition given in Table 3 was separated from the gases containing heavy metals.

Table 1

Table 2

Table 3

Beispiel 2

Example 2

1000 kg / h of iron and heavy metal-containing residues, which had a composition shown in Table 1, and 10 Nm ³ / t of gaseous reducing agent were introduced into the melting cyclone and swirled and ignited with 200 NmVt oxygen. The introduction of solid carbon-containing reducing agents was not necessary due to the high carbon content of the residues.

The resulting melt and the gases containing heavy metals were separated in the separating vessel. The melt was transferred to the metallurgical vessel and reduced with 100 kg / t coal. The electricity requirement of the device for heating the metallurgical vessel was 200 kWh / t. An iron melt and a slag with the compositions given in Table 2 were obtained.

The CO-containing gases were afterburned in the upper area of the metallurgical vessel with 30 NmVt oxygen.

20 kg / t of used foundry sand were introduced into the metallurgical vessel to build up a slag feed on the retained melt sump.

A heavy metal product with a composition given in Table 3 was separated from the gases containing heavy metals.

Claims

claims: 1. A process for recycling solid residues containing iron and heavy metals, optionally with the addition of iron ore, the residues together with reducing agents, such as coal and / or coke and / or carbon-containing and / or hydrocarbon-containing residues and / or hydrocarbons in solid and / or in liquid and / or gaseous form, and oxygen and / or oxygen-enriched air are introduced, swirled and ignited into a melting cyclone (6), the residues are melted, volatile heavy metals are reduced and evaporated and iron oxides are reduced, the gases and the melt the melting cyclone (6) is transferred jointly to a directly coupled separating vessel (7), in which the melt and gases are separated, the evaporated heavy metals are separated from the gases outside the separating vessel (7) and the melt is transferred to a separating vessel (7 ) separate metallurgical vessel ( 10) is transferred, characterized in that, on the one hand, reducing agents are fed into the metallurgical vessel (10), the iron oxides of the melt are reduced to iron to form a low-iron slag and, on the other hand, electrical energy is introduced to at least partially cover the heat losses and the reduction energy. 2. The method according to claim 1, characterized in that the gases afterburning immediately after exiting the separating vessel (7) by means of air or oxygen-enriched air and the heavy metals are brought into a solid oxidic form and then separated from the gases. 3. The method according to claim 2, characterized in that the gases are cooled after the afterburning to produce steam in a heat exchanger (8). 4. The method according to claim 1, characterized in that the gases emerging from the separation vessel (7) are quenched with water, the heavy metals are separated from the gases and the cleaned gases are supplied for use. 5. The method according to any one of claims 1 to 4, characterized in that for the direct reduction of iron oxides to iron as a carbon-containing reducing agent Coke and / or coal and / or carbon-containing and / or hydrocarbon-containing residues are introduced into the metallurgical vessel (10). 6. The method according to claim 5, characterized in that a part of the iron oxides to be reduced is reduced by means of carbon monoxide formed in the reduction of iron oxide with carbon-containing reducing agent. 7. The method according to any one of claims 1 to 6, characterized in that for the transfer of non-volatile heavy metals, which can not or only partially reduced by adding carbon-containing reducing agents, in the molten metal, a stronger reducing agent, preferably ferrosilicon or aluminum, in the metallurgical Vessel (10) is introduced. 8. The method according to any one of claims 1 to 7, characterized in that the gases formed during the reduction are burned by means of oxygen or oxygen-enriched air in the upper region of the metallurgical vessel (10). 9. The method according to any one of claims 1 to 8, characterized in that the electrical energy is introduced via electrodes in the metallurgical vessel (10). 10. The method according to any one of claims 1 to 9, characterized in that the electrical energy is introduced inductively into the metallurgical vessel (10). 11. The method according to any one of claims 1 to 10, characterized in that the energy required for the reduction and coverage of the heat losses is introduced in part by means of a burner in the metallurgical vessel (10). 12. The method according to any one of claims 1 to 11, characterized in that the melt is stirred during the reduction and / or during the introduction of energy, preferably by rinsing the floor. 13. The method according to any one of claims 1 to 12, characterized in that the molten iron is heated to a temperature suitable for a subsequent casting process, preferably by means of electrical energy. 14. The method according to any one of claims 1 to 13, characterized in that a desired composition of the molten iron is set by adding alloying substances. 15. The method according to any one of claims 1 to 14, characterized in that the gases formed in the metallurgical vessel (10) are suctioned off and cleaned, the separated dust preferably being fed to the melting cyclone (6) as a residue. 16. The method according to any one of claims 1 to 15, characterized in that the slag and the iron melt are poured separately. 17. The method according to any one of claims 1 to 16, characterized in that a metal melt sump is retained in the metallurgical vessel (10) after pouring off the slag and the iron melt and this in the metallurgical vessel (10) as a template with a high carbon content and high temperature for a new batch of melt is used. 18. The method according to any one of claims 1 to 17, characterized in that a low-iron slag, preferably by introducing residues such as fly ash, foundry sand and coke and / or coal, is formed over the melting sump and melting sump and slag in the metallurgical vessel (10) can be used as a template for a new batch of melt. 19. The method according to any one of claims 1 to 18, characterized in that the reduction of the melt on the one hand and the conditioning on the other hand is carried out at separate locations, using a transportable metallurgical vessel (10). 20. The method according to any one of claims 1 to 19, characterized in that the reduction of the melt on the one hand and the introduction of electrical energy on the other hand is carried out at separate locations, wherein a transportable metallurgical vessel (10) is used. 21. The method according to any one of claims 1 to 20, characterized in that it is carried out semi-continuously, with at least two transportable metallurgical vessels (10), preferably pans, are used. 22. The method according to any one of claims 19 to 21, characterized in that the melt between the separating vessel (7) and the transportable metallurgical vessel (10) in a stationary storage device for bridging process interruptions, such as heating periods, vessel changes etc., is temporarily stored. 23. The method according to any one of claims 19 to 21, characterized in that the melt in the separating vessel (7) is temporarily stored in the time in which no melt can be fed into the transportable metallurgical vessel (10), especially if the metallurgical vessel (10) for pouring and / or conditioning the melt and / or for introducing the electrical energy to another location. 24. The method according to any one of claims 1 to 23, characterized in that the iron and heavy metal-containing residues are collected separately in heavy metal and low heavy metal residues and used separately in the melting cyclone (6) and that separated heavy metals from the gases when using heavy metal low residues the heavy metal rich Residual materials are supplied. 25. The method according to any one of claims 1 to 23, characterized in that the heavy metals separated from the gases are collected and used again in the melting cyclone (6) up to a desired enrichment of the heavy metals for the discharge, in particular regulated with continuous measurement of one or more Heavy metal concentrations in the separated dust. 26. The method according to any one of claims 1 to 25, characterized in that the heat losses from the melting cyclone (6) and / or the separating vessel (7) are used to generate steam. 27. The method according to any one of claims 1 to 26, characterized in that the slag is allowed to solidify after pouring and is then recycled, preferably in cement production. 28. Plant for the recycling of iron and heavy metal-containing residues, optionally with the addition of iron ore, using the method according to one of claims 1 to 27, characterized by the combination of the following features: An essentially vertical melting cyclone (6), which has a bottom opening for the escape of gases and melt, one or more essentially horizontal feeds for solid feedstocks and for gases, and gases, and an ignition device opening into the melting cyclone (6), A separating vessel (7) which is directly coupled to the melting cyclone (6) and has an opening for the escape of gases and a second opening for the exit of the melt, An exhaust gas line, which starts from the exhaust opening of the separating vessel (7) and leads to a device (9) for separating the heavy metals from the gases escaping from the separating vessel (7), At least one metallurgical vessel (10) which has at least one device for supplying reducing agent and at least one device for pouring off molten iron and slag, • A device for transferring the melt from the melt outlet opening of the separating vessel (7) into the metallurgical vessel (10) and • A device for electrical heating of the metallurgical vessel (10). 29. Plant according to claim 28, characterized in that the exhaust pipe from the separating vessel (7) is equipped with an opening for the supply of air or oxygen-enriched air. 30. Plant according to claim 29, characterized in that the opening is designed in the form of a sliding sleeve. 31. Plant according to one of claims 28 to 30, characterized in that the device (9) for separating the heavy metals is designed as a bag filter unit. 32. Installation according to one of claims 28 to 31, characterized in that the metallurgical vessel (10) is equipped with at least one lance and / or nozzle for blowing in reducing agent. 33. Installation according to one of claims 28 to 32, characterized in that a device for blowing oxygen into the metallurgical vessel (10) is provided. 34. Installation according to one of claims 28 to 33, characterized in that a burner is provided in the metallurgical vessel (10). 35. System according to one of claims 28 to 34, characterized in that the device for electrical heating is designed in the form of graphite electrodes or an inductive heating. 36. Plant according to one of claims 28 to 34, characterized in that a device for stirring the melt, such as floor rinsing nozzles, is provided in the metallurgical vessel (10). 37. Installation according to one of claims 28 to 36, characterized in that the metallurgical vessel (10) is designed to be transportable. 38. System according to claim 37, characterized in that a transport device for moving the (r) metallurgical vessel (s) (10) is provided. 39. Installation according to one of claims 28 to 38, characterized in that a feed device for feeding lumpy and / or fine-grained materials into the metallurgical vessel (10) is provided. 40. Installation according to one of claims 28 to 39, characterized in that a heat exchanger (8), preferably a steam boiler, is provided in the exhaust line starting from the separating vessel (7). 41. Plant according to one of claims 28 to 40, characterized in that the melting cyclone (6) and / or the separating vessel (7) are equipped with a cooling device. 42. Plant according to one of claims 28 to 41, characterized in that a storage device for the melt in the form of a tilting channel is provided next to the outlet opening of the separating vessel (7) for the melt. 43. Installation according to claim 42, characterized in that the tipping channel is lined with refractory material and / or is equipped with a burner to cover heat losses.