AU744597B2

AU744597B2 - Method for producing zinc using the is process in an is shaft furnace and corresponding is shaft furnace

Info

Publication number: AU744597B2
Application number: AU52850/99A
Authority: AU
Inventors: Hans-Gunther Rachner; Wolf-Dieter Schneider
Original assignee: M I M HUTTENWERKE DUISBURG GMB; Kuettner GmbH and Co KG
Current assignee: Mim Huttenwerke Duisburg GmbH; Kuettner GmbH and Co KG
Priority date: 1998-07-20
Filing date: 1999-07-20
Publication date: 2002-02-28
Anticipated expiration: 2019-07-20
Also published as: CN1182264C; EP1105544B1; PL345591A1; EP1105544A1; PL189908B1; JP2002521563A; AU5285099A; DE19841980A1; DE19841980C2; DE59903049D1; CN1310768A; WO2000005424A1

Description

L1 1 Method for producing zinc using the IS process in an IS shaft furnace and corresponding IS shaft furnace The invention concerns a method to produce zinc according to the IS process in an IS shaft furnace installation and an IS shaft furnace installation to carry out this method.

The IS (Imperial Smelting) process to produce zinc as well as IS shaft furnace installations have been known for a long time. The IS process is characterised in that both zinc and lead are produced as raw materials with great yield in one operation. In the case of the known method the furnace is charged with coke and sinter. In addition, secondary dusts, concentrated and briquetted in a rotating pipe, are charged. The disadvantage of this state-of-the-art is that the stages of the concentrating process of the dusts in the rotating pipe and the briquetting are not only labour and cost intensive, but are also damaging to the environment.

The invention follows a new path. According to the invention first of all a finegrained dust mixture, containing a carbon carrier and zinc, is directly injected into the lower region of the IS shaft furnace. The direct injection into the reducing zone of the IS shaft furnace produces a number of advantages. The zinc will be obtained as metal directly from the secondary dust without an intermediate stage, like rolling or briquetting. Analyses of the products of IS shaft furnaces show that at least 80% of the injected dusts, based on the total injected amount, is utilised.

Moreover, the amount of coke can be reduced when the zinc dust is injected with the carbon carrier, leading to considerable cost reduction, since a fine-grained carbon carrier is considerably more cost-effective than the coke used conventionally. Incidentally, the injection of carbon into the reducing zone of the IS shaft furnace provides a possibility to blow the slag off the hot blast nozzles to reduce the ZnO content in the slag and thus to reduce the zinc losses of the process on the one hand and to produce the slag with a more environmentally friendly analysis on the other. Influences that have a negative affect on the furnace operation, caused by the direct injection, could not be detected.

r-8; In the case of the invention the fine-grained carbon carrier is not only metallurgically utilised, but assures the transportability of the dust also, since the transport of the dust by pneumatic means is not possible at all or only with great difficulty. By injecting the dust mixture according to the invention the furnace management with regard to the furnace gas analysis will be drastically changed.

The CO content and the H 2 content increase by at least 10 and 30 respectively, so that a richer furnace gas is obtained.

It has been further established that an IS shaft furnace installation operating in accordance with the method of the invention, also in combination with a sintering plant, a hot briquetting and the direct injection, makes it feasible to offer a satisfactory technology for various materials. The sintering plant with its sulphuric acid production connected downstream can utilise in addition to the classic ore concentrates all those residues that contain sulphur. Moreover, there is the possibility to process filter cakes, sludges, oxide and halogen-containing materials. Hot briquetting is a process whereby the secondary materials, free of sulphur, are processed. In this case the material may vary between dry and moist, having coarse and fine grain. In this case typical initial materials are rolling oxide, filter dusts, dross and ash, that are conditioned for the use in the IS shaft furnace. Dusts, in particular those originating from gas purification plants of the iron and steel industries, that are fine and dry, are utilised to their optimum by the direct injection. In this case metal is formed directly from residual material and/or waste, without prior concentration or other processes being necessary. Typically for the method, neither lead nor copper interfere here, since both metals are recovered in the IS process. Organic adhesions to the materials, e.g. dioxins, are destroyed by the injection into the hot nozzle zone in the IS shaft furnace.

To achieve a good transportability of the dust mixture the average grain size of the carbon carrier is between 10 and 200 pm, preferably approx. 50 pm while the average grain size of the dust is smaller than 50 pm, preferably smaller than pm. Therefore the carbon carrier having the aforementioned average grain diameter is particularly well suited as conveying or transporting medium for fine dusts, since the dust particles are smaller than the particles of the carbon carrier, N which, as a rule, have a very uneven surface, so that the dust particles can well 3 embed themselves in or adhere to the particles of the carbon carrier. At the same time it has been established that fine coal, anthracite, coke fines, brown coal dust as well as synthetic materials, for example, and mixtures of the aforementioned materials can be used as carbon carrier. Zinc dust, zinc ash, metallurgical copper dust, blast furnace dust, steel mill dust, recirculated cupola furnace dust, brass dust and/or lead dust can be used as zinc-containing dust. The dust should have a minimum content of 15 of zinc. There is no upper limit for the zinc contents.

Dusts having a zinc or lead contents below 15 should be subjected to a concentration connected upstream. The charge materials may be free of lead or contain considerable amounts of lead particles. Even residual materials containing purely lead can be used.

A good transportability of the dust mixture is achieved also by mixing the carbon carrier and the dust in a weight ratio of at least 0.5:1 and preferably in such a ratio that corresponds to the Zn/C ratio of the IS shaft furnace 2, in particular 1:1.

This mixing ratio takes the physical point of view of the transportability of the dust mixture into consideration in the first place and the metallurgical aspects are of lesser consequence.

Furthermore, it has been established that it is advantageous to convey the dust mixture from the injecting device by pneumatic means and preferably continuously to the IS shaft furnace. This type of conveying can be easily realised. It has been established that the conveying can be carried out in flying stream with velocities of up to 25-30 m/s or in the case of a corresponding material in dense stream with up to 10 m/s.

If required, the direct injection provides the further possibility to influence the metallurgical process in a simple manner, whereby the injected amount of dust, carbon carrier or dust mixture or the ratio of dust to carbon carrier is modified. For this purpose the dust, the carbon carrier and the dust mixture is conveyed with an inert gas, preferably with nitrogen, the dust to carbon carrier ratio is adjustable and the amount of the gas for fluidisation, conveying and setting the velocity of the dust mixture can be controlled.

In addition, the direct injection provides in a simple manner the possibility to influence the temperature in the subhearth of the IS shaft furnace. For this purpose the temperature of the injected forming gas is measured on the hot blast nozzles of the IS shaft furnace as a function of the state of the slag and the injecting device is controlled on the basis of the measured results in such a manner that a basically constant temperature is set at least in the bottom region of the IS shaft furnace. For this purpose in addition to the dust mixture, a gas mixture of nitrogen and of oxygen and/or of air is injected into the IS shaft furnace through the coaxial lances via an annular gap of the coaxial lances, whereby the amount of the gas mixture and the ratio of the nitrogen to the oxygen and/or the air can be controlled particularly as a function of the temperature of the coaxial lances and/or of the IS shaft furnace.

Further features, advantages and possibilities of application of the invention become apparent from the sub-claims, the following description of embodiments based on the drawing and the drawing itself.

The single figure shows a schematic illustration of a part of the IS shaft furnace installation 1 according to the invention, having an IS shaft furnace 2 and an injection device 3. Through the injection device 3 a fine-grained dust mixture is injected into the IS shaft furnace 2, this mixture having a carbon carrier and dust containing zinc. As it has been explained earlier, as injection material zinc dusts of various origins and as carbon carrier preferably fine coal is used.

In the embodiment illustrated the injection device 3 has a storage device 4 having a total of four silos 5, 6, 7, 8. In the case of the injection device 3 illustrated at least two silos are provided for the storage of dust and the remaining silos are provided for the carbon carrier. As a rule, the silos 5, 6, 7, 8 are filled from road tankers in a sealed system under pressure, so that no dust can escape to the outside. It is also possible to discharge the road tankers into transportable silos that are coupled with the silos 5, 6, 7, 8 and the number of which corresponds to that of the silos 5, 6, 7, 8.

The transport and the conveying of the carbon carrier and of the dust is carried out by nitrogen. However, basically the use of another inert gas is also feasible.

The IS shaft furnace installation 1 has a nitrogen tank (not illustrated) for the nitrogen, that is stored in liquid form. The nitrogen is vapourised using a cold vapouriser and after reducing the pressure it has a supply pressure of 14-15 bar.

The relevant silo(s) can be made inert any time, should trouble occur. To enable to determine troubles, the entire IS shaft furnace installation 1 is being monitored and is connected with a control centre. In addition, a control device is provided to enable to control, when required, the process and the entire plant and to enable to react to troubles at any time.

In the case of the IS shaft furnace 1 according to the invention the nitrogen is used for other purposes also, what will be explained in detail in the following. It serves, inter alia, the purpose of cooling the coaxial lances of the injection device, of transporting the dust mixture, of increasing the pressure in the injection vessel (to be described in detail below) as well as of blowing free or blowing back of blocked lines. The nitrogen is used also for the loosening of the dust and of the carbon carrier in the silos 5, 6, 7, 8 and all other containers or devices that are passed through by the dust mixture. Corresponding line connectors are present in the silos, containers and devices, in particular in the region of the bottom, to enable the loosening and fluidisation of the material from below. Since particularly the dust is considered as a material with problems with regard to its storage and transport and its hygroscopic properties (lumping), the silos 5, 6, 7, 8 have vibrating bottoms in the region of their discharges and are insulated and heated.

Each of the silos 5, 6, 7, 8 is connected with a weighing device 13 via a screw conveyor 9, 10, 11, 12, respectively. The screw conveyors 9,10, 11, 12 are also insulated and heated. A slide gate each is provided between the silos and the respective screw conveyor, the slide gate being controlled by the control mechanism just as all other slide gates described later can be controlled. The measuring of the level, pressure and temperature by corresponding means is feasible in each silo 5, 6, 7, 8.

The amounts of carbon carrier and dust to be carried from the relevant silos 5, 6, 7, 8 via the respective screw conveyors 9, 10, 11, 12 depend on the type and composition of the material concerned. After establishing the composition of the material concerned, the ratio of the dust to the carbon carrier to be charged is determined by means of the control device of the IS shaft furnace installation 1.

This ratio should be such that the Zn/C ratio of the dust mixture would correspond approximately to that of the IS shaft furnace 2. In addition, so that the dust mixture could be pneumatically transported at all in dense stream, the weight ratio of the carbon carrier to the dust has to be at least 0.5:1. The weight ratio of the pneumatically transported dust mixture is preferably about 1:1.

In the case of the weighing device 13 one deals with a weighing hopper. The weighing device 13 is also insulated and heated. In the bottom region of the weighing device 13 inlets are provided to enable the loosening of the material by introducing nitrogen. The weighing device 13 is connected with a mixing device 14 via at least one slide gate; the mixing device is also insulated and heated and the homogenising of the dust mixture, i.e. the attachment of the dust particles on the fine coal grains, takes place in it.

The discharge from the mixing device 14 takes place via a corresponding discharge device 15; in the present case one deals with a bucket wheel gate. A slide gate is positioned between the mixing device 14 and the discharge device Positioned downstream from the mixing device 14 and the discharge device there is a classifying device 16; in the present case one deals with a sieving machine to which a sluicing hopper 17 is connected. The classifying device 16 has such a construction that the undersize grain is below 2 mm. A pneumatically actuated slide gate is positioned between the classifying device 16 and the sluicing hopper 17. As is the case in the previously described devices, the sluicing hopper 17 is insulated and is heated and has a level and pressure measuring equipment. Incidentally, in its bottom region the sluicing hopper 17 has appropriate openings to enable the loosening of the dust mixture in the sluicing Shopper 17.

i i; i-c r. L. ::l The sluicing hopper 17 is connected to an injection vessel 18, while in the line between the sluicing hopper 17 and the injection vessel 18 at least one pneumatically actuated slide gate is provided. After filling and pressurising the sluicing hopper 17 with a pressure that corresponds to that in the injection vessel 18 of approx. 2.0-7.0 bar (depending on the type and composition of the dust mixture), both vessels are connected with each other, so that the dust mixture will flow from the sluicing hopper 17 into the injection vessel 18. After emptying the sluicing hopper 17 into the injection vessel 18 the connection is severed and the sluicing hopper 17 can be refilled. The coupling of the sluicing hopper 17 with the injection vessel 18 makes a continuous supply of the dust mixture from the injection vessel 18 to the IS shaft furnace 2 possible, what would be impossible without the sluicing hopper 17.

The filling of the sluicing hopper 17 and of the injection vessel 18 takes place as follows: when the mixing time in the mixing device 14 has elapsed, the sluicing hopper 17 can be filled. At this stage the sluicing hopper 17 is not under pressure. The sluicing hopper 17 is filled until the maximum filling level is reached. The transfer can commence at this stage. The plant is constructed in such a manner that that amount which is in the sluicing hopper 17 can be accommodated by the injection vessel 18. The correct progress of the transfer is assured by the control device. When pressurising the sluicing hopper 17 with nitrogen, care is to be taken that the pressure in the sluicing hopper 17 equals the pressure in the injection vessel 18. When this condition is reached, the inlet into the injection vessel 18 is opened and the dust mixture flows from the sluicing hopper 17 into the injection vessel 18. After emptying the sluicing hopper 17 the connection between the injection vessel 18 and the sluicing hopper 17 is interrupted again. Following this the sluicing hopper 17 can be depressurised. On this occasion care is to be taken that during the transfer the pressure in the injection vessel 18 remains on such a level that it can further inject the dust mixture into the IS shaft furnace 2, i.e. during and also after the transfer. If necessary, after the transfer the pressure in the injection vessel 18 is to be corrected or adjusted.

In this present case eight loosening vessels 19 are connected downstream from the injection vessel 18, of which only one is shown. The loosening vessels 19 are arranged below the injection vessel 18, while between each loosening vessel 19 and the injection vessel 18 a slide gate is provided, so that the respective loosening vessels can be alternately separated from the injection vessel 18 when certain coaxial lances of the IS shaft furnace 2 are not to be charged. Each of the loosening vessels 19 can be pressurised from below and has a porous bottom plate that serves as loosening bottom. The discharge of the loosening vessels is always in its top region.

In the case of the construction according to the invention the loosening and fluidising of the dust mixture is further improved by providing at least one additional line from above into each loosening vessel 19 to supply further nitrogen to accelerate the dust mixture, which line preferably terminates in the form of an annular nozzle. Incidentally, the supply of the so-called by-pass gas via the annular nozzle makes it feasible to control the dust mixture flow independently from the pressure in the injection vessel.

A feed line leads from each loosening vessel 19 in the direction of the IS shaft furnace 2. The feed lines commence in the loosening vessels 19 on the discharge of the injection vessel 18. The dust mixture is conveyed from the injection vessel 18 via the individual loosening vessels 19 and from there via the feed lines into the IS shaft furnace 2. The optimum ratio of dust to gas, necessary for pneumatic conveying, is adjusted by loosening the dust mixture in the loosening vessels 19.

The dust mixture is conveyed in dense steam of flying steam, depending on the type of the dust. The amount of gas introduced for the purpose of fluidising into the respective loosening vessel 19 is monitored and controlled by the control device. For each dust mixture a certain nominal value for the loosening is specified, depending on its composition. The velocity and the system pressure are also functions of the type of the dust mixture. The least abrasion occurs in the feed lines in the case of pneumatic conveying, wherein the velocity of the dust mixture is up to 10 m/s.

9 All feed lines, and preferably all other lines of the injection device 3, are insulated and, possibly, heated, at least when the feed lines are installed on the exterior of the plant. To avoid blockages in the individual feed lines by the dust mixtures that are very difficult to convey and to keep the velocity of the dust mixture essentially constant, the lines have a cross-section that increases towards the IS shaft furnace and they do not have throttles like the ones often provided in feed lines for other materials.

It is not illustrated that a blowing free of at least a major portion of the lines is possible in the direction of the IS shaft furnace 2 and a reverse blowing in the opposite direction. For this purpose connections with corresponding valves in the lines are provided at various positions, which enable a blowing free and a reverse blowing. The possibility of blowing free and reverse blowing has to be provided to enable the prevention of possible blockages on the lines. A blowing free should be preferably possible from the injection vessel 18 up to the IS shaft furnace 2.

The recognition of blockage and consequently the control of the blowing free and reverse blowing by the control device is based on measuring the pressure in the individual feed lines.

Two coaxial lances or two hot blast nozzles 20 of the IS shaft furnace 2 are assigned to each loosening vessel 19 and to each feed line from the respective loosening vessel 19. In principle it is, of course, feasible to provide one loosening vessel and one feed line for each lance or each hot blast nozzle 20. This is, however, relatively elaborate and costly. Theoretically it is equally feasible to provide only one loosening vessel with one feed line and then feed the individual coaxial lances or hot blast nozzles via an expensive distributing mechanism. In the case of the construction according to the invention a uniform supply of the individual lances is assured by assigning two coaxial lances to each loosening vessel 19, while in the corresponding feed line a simple T-joint is provided as distributor. However, in principle both lances can be regulated and controlled separately from each other. In principle it is true that a single control of the lances (each lance on its own) as well as a total control (all lances together) may be provided.

As it has been explained above, coaxial lances are used as lances. In addition to the dust mixture a gas or a gas mixture is added through these coaxial lances via an external annular gap, the purpose of the gas or the gas mixture being, inter alia, cooling. The gas may be nitrogen, a nitrogen/oxygen mixture or oxygen only.

Instead of oxygen air may be used. The ratio of nitrogen to oxygen/air as well as the amount of the gas supplied can be controlled by the control device. The individual lances can be cooled by the gas mixture, while the added oxygen serves also to compensate for the drop of the temperature in the IS shaft furnace before the respective hot blast nozzle. A mixing station (not illustrated), that can be controlled by the control device, is provided for the adjustment of the mixture ratio. On or in the IS shaft furnace 2, in the region of the hot blast nozzles 20, a temperature monitoring of the furnace and, in particular, of the coaxial lances is provided. In addition the amount of dust mixture supplied to each lance or to each pair of lances is measured. The measuring is carried out continuously. The amount of the dust mixture, of the gas mixture and/or the ratio of nitrogen to oxygen is controlled as a function of the measured results.

Incidentally, the temperature of the injected forming gas in the IS shaft furnace 2 on all hot blast nozzles 20 can be measured depending on the state of the slag.

Depending on the result of the temperature measurement, the injection device 3 can be so controlled that the temperature in the subhearth of the IS shaft furnace 2 and the temperature of the injected forming gas can be held basically constant, for example at approx. 1800 oC. In addition, the process technology makes it feasible to inject only the carbon carrier to enable a better control of the furnace when starting it up or closing it down and to save other fuels, like, for example, coke.

Claims

1. A method to produce zinc according to the IS process in an IS shaft furnace installation that has an IS shaft furnace and an injection device wherein a fine-grained dust mixture having a dust containing carbon carrier and zinc is injected into the bottom region of the IS shaft furnace characterised in that the average grain size of the carbon carrier is between and 200 pm, that the average grain size of the dust is smaller than 50 pm, and that the carbon carrier and the dust are mixed in a weight ratio of at least 0.5:1.

2. A method according to claim 1, characterised in that the average grain size of the carbon carrier is approx. 50 pm and that the average grain size of the dust is smaller than 10 pm and/or that the carbon carrier and the dust are mixed in a weight ratio that corresponds to that of the Zn/C ratio of the IS shaft furnace

3. A method according to claim 1 or 2, characterised in that the dust mixture is conveyed pneumatically from the injection device and continuously to the shaft furnace

4. A method according to any one of the preceding claims, characterised in that the dust, the carbon carrier and the dust mixture are conveyed with an inert gas, like nitrogen, that the ratio of dust to the carbon carrier can be adjusted and that the amount of the gases for fluidising, conveying and adjusting the velocity of the dust mixture can be controlled. A method according to any one of the preceding claims, characterised in that the temperature of the injected forming gas is measured on the hot blast nozzles (20) of the IS shaft furnace as a function of the state of the slag and the injecting device is controlled in such a manner that a basically constant temperature is set at least in the bottom region of the IS shaft furnace 4, AMENDED PAGE r :iS1- u lo, 12

6. A method according to any one of the preceding claims, characterised in that in addition to the dust mixture, a gas mixture of nitrogen as well as of oxygen and/or of air is injected into the IS shaft furnace through the coaxial lances via an annular gap of the relevant coaxial lances, and that the amount of the gas mixture and the ratio of the nitrogen to the oxygen/air can be controlled as a function of the temperature of the coaxial lances and/or of the IS shaft furnace.

7. A method to produce zinc according to the IS process in an IS shaft furnace installation that has an IS shaft furnace and an injection device wherein a fine-grained dust mixture having a dust containing carbon carrier and zinc is injected into the bottom region of the IS shaft furnace characterised in that in addition to the dust mixtui'e a gas mixture of nitrogen as well as of oxygen and/or of air is injected into the IS shaft furnace (2) through the coaxial lances via an annular gap of the relevant coaxial lances, that the amount of the gas mixture and the ratio of the nitrogen to the oxygen/air can be controlled as a function of the temperature of the coaxial lances and/or of the IS shaft furnace and that the amount of dust mixture conveyed to each lance or to each pair of lances is continuously measured and the amount of the dust mixture and/or the ratio of nitrogen to oxygen of the gas mixture is controlled as a function of the measured results.

8. A method according to any one of the preceding claims, characterised in that fine coal and/or anthracite and/or coke fines and/or brown coal dust and/or synthetic materials is/are used as carbon carrier, and/or that zinc dust, metallurgical copper dust, blast furnace dust, steel mill dust, recirculated cupola furnace dust, brass dust, zinc ash and/or lead dust is/are used as zinc- containing dust.

9. A method according to any one of the preceding claims, characterised in that the velocity of the dust mixture during injection may be a maximum of 30 m/s and/or that in the injection vessel (18) a pressure of at least 1 bar prevails. I AMENDED PAGE i ~i /At' 13 A method according to any one of the preceding claims, characterised in that for starting up the IS shaft furnace only the carbon carrier is injected.

11. An IS shaft furnace installation with an IS shaft furnace and an injection device to inject a fine-grained dust mixture having a dust containing a carbon carrier and zinc is injected into the IS shaft furnace in particular to carry out the method according to any one of the preceding claims, characterised in that the injection device has at least one loosening vessel (19) that is connected downstream to the injection vessel that the loosening vessel (19) can be pressurised from below and it has a porous bottom plate, that at least one additional line is provided from above into the loosening vessel (19) to supply a by-pass gas to accelerate the mixture, which line terminates in a nozzle and to control the dust mixture independently from the pressure in the injection vessel.

12. An IS shaft furnace installation according to claim 11, characterised in that a separating slide gate is provided between the loosening vessel (19) and the injection vessel (18).

13. An IS shaft furnace installation according to claim 11 or 12, characterised in that the cross-section of the lines increases from the injection device to the IS shaft furnace

14. An IS shaft furnace installation according to any one of claims 11 to 13, characterised in that connections and non-return valves are provided on the lines in the injection device and from the injection device to the IS shaft furnace which enable a blowing free of the lines towards the IS shaft furnace and a reverse blowing in the opposite direction and/or that the injection device and/or the lines to the IS shaft furnace are heated at least partially. -IL AMENDED PAGE 4 ir 6 14 An IS shaft furnace installation according to any one of claims 11 to 14, characterised in that two coaxial lances in the IS shaft furnace are assigned to each loosening vessel (19) and that a T-piece is provided as distributor.

16. An IS shaft furnace installation according to claim 15, characterised in that a gas mixing station that is coupled with the coaxial lances of the IS shaft furnace is provided for mixing nitrogen on the one hand and/or air on the other by means of which the amount and the ratio of the nitrogen to oxygen/air can be adjusted.

17. An IS shaft furnace installation according to claim 15 or 16, characterised in that a monitoring of the temperature of the coaxial lances is provided.

18. An IS shaft furnace installation according to any one of claims 11 to 17, characterised in that a control device for controlling the injecting pressure as a function of the temperature of the coaxial lances and/or of the temperature in the IS shaft furnace is provided and/or for the controlling of the amount of dust and carbon carrier charged as a function of the composition of the dust and of the carbon carrier and/or that the control device is coupled with the gas mixing station.

19. An IS shaft furnace installation with an IS shaft furnace and an injection device to inject a fine-grained dust mixture having a dust containing a carbon carrier and zinc is injected into the IS shaft furnace in particular to carry out the method according to any one of the preceding claims, characterised in that coaxial lances having annular gaps are provided for the injecting of the dust mixture, that a gas mixing station that is coupled with the annular gap of the coaxial lances is provided for mixing nitrogen on the one hand and oxygen and/or air on the other, by means of which the amount and the ratio of the nitrogen to oxygen/air can be adjusted, that a temperature monitoring of the coaxial lances is provided and that a control device, connected with the gas mixing station, for controlling the injecting Zpressure as a function of the temperature of the coaxial lances and/or of the AMENDED PAGE '4 temperature in the IS shaft furnace is provided and/or for the controlling of the amount of dust and carbon carrier charged as a function of the composition of the dust and of the carbon carrier.

20. An IS shaft furnace installation according to any one of claims 11 to 19, characterised in that the injection device has a storage device with at least one silo for the dust and at least one silo for the carbon carrier, a weighing device (13) that is connected downstream from the storage device a mixing device (14) that is connected downstream from the weighing device (13), a classifying device (16) that is connected downstream from the mixing device, at least one sluicing hopper (17) that can be pressurised and is connected downstream from the classifying device and at least one injection vessel (18) that can be pressurised and is connected downstream from the sluicing vessel (17). AMENDED PAGE i~i" ~i iY.~i_ -_lili..~i .i 1I1.~n. il~iW-i: r~q~-71~b