DE2644187A1 - SINTER RUST OF SULFUR-CONTAINING MATERIAL - Google Patents

Description

Dipl.-Ing. Heinz Bardehle £ σ Η ^ ίο /

Patent attorney ^.

8 Munich 22, Herrnstr. 15, Tel. 292555 · "·

Postal address Munich 26, Postfacb 4

My reference: P 2397 Munich, September 30, 1976

Applicant: Metallurgie Hoboken-Overpelt 8, Montagne du Pare
Brussels Belgium

Sinter roasting sulphurous material

The invention relates to a method for sinter roasting sulfur-containing material as described in the preamble of the claim 1 is indicated and to a device to be used in connection with the method.

The invention relates to a method for sintering a layer or a layer from a sulfur-containing charge such as e.g. one based on a concentrate of lead, lead and zinc, lead and copper or copper. This roasting takes place on an endless grate such as a Dwight-Lloyd device, which works with an upward or downward (air) draft, with gases containing sulfur dioxide SO-

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are obtained, which are subsequently used for the production of sulfuric acid be used.

In more detail, the invention deals with a new one Method and device for igniting the layer which is to be treated according to the sinter roasting method.

The layer of the batch to be roasted in a Dwight-Lloyd apparatus is ignited beneath an ignition hearth or furnace. This stove is lined with highly refractory bricks or stones and equipped with gas or oil burners, which are arranged vertically in an arch or horizontally in at least one of the posts or pillars of this stove. The charge is then ignited by arc radiation primarily by conduction through contact with the hot gases passing through the charge. The gases emitted into the suction box of the Dwight-Lloyd device contain, in addition to the combustion products of the oil or gas (H ₂ O, CO ₂ , CO, O ₂ , N ₂ ), a certain amount of SO ₂ up to 1%. This is due to the roasting of the ignited batch. Sometimes these are returned to the atmosphere, regardless of the SO ₂ content. More often they are returned as low-content gases under the hood or into the last boxes of the Dwight-Lloyd device. The only release of gas in this device is in the form of a high content gas for the production of sulfuric acid.

However, it is generally known that when using the ignition process described above, more precisely when sintering batches consisting of material based on the zinc blende, the SO ₃ content of these highly SO 4 -containing or enriched gases does not reach the desired level in order to operate a factory for the production of sulfuric acid H ₂ SO ₄ economically, this production being carried out either by the contact process (single or double catalysis) or by the lead chamber process.

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In US Pat. No. 1,861,122, it is described that in a Dwight-Lloyd device to ignite the existing layer of the charge by burning powdered, high-sulfur ore, which is brought into contact with the bed in an air blast, with the burning pulverized ore on the bed deposits. This firing or this ignition with pulverized ore has the advantage that it is used for roasting the high sulfur content Ore (e.g. pyrith or zinc blende) is to be used in such a way that these ores, as is usually the case, do not have to be roasted beforehand. Firing of this kind can also result in a slight increase in the 30 ~ - Cause content of the exhaust gases from the Dwight-Lloyd device. However, this has the disadvantage that the to be ignited Layer of the batch of blown, burning ore considerably reduced the permeability of the layer. This penetrability however, it is very important for the further sinter roasting of the ignited layer. It also requires the need or availability of high sulfur ores, the presence of these in the roasted state in the sintered roasted Batch must not interfere with the further treatment of the same.

It is an object of the present invention to overcome the disadvantages of prior art methods set out above fix or work around.

This task is done with a like in the preamble of the claim 1 specified method solved, which is characterized as the characterizing part of claim 1 indicates. From the subclaims can be further refinements and developments of the invention and one in connection with the invention Remove the device to be used.

The present invention is thus concerned with a method for sintering a layer of sulfur-containing material, this being done on an endless grate and the layer through Contact with a stream of hot gases below an inflammatory

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• Υ

stove or stove is ignited. The gases resulting from the ignition are added to the SO ₂ -containing gases that are generated during the subsequent sinter roasting of the ignited layer. These gases are later used to produce sulfuric acid. The novel process according to the invention is characterized in that the flow of hot gases is generated by the combustion of elemental sulfur with oxygen, which is contained in a gas which supports or maintains the combustion.

It should be pointed out that the expression "SO ₂ -containing gases which are used during the subsequent sinter roasting of the ignited layer and which are later used for the production of sulfuric acid" as used _{above includes both the strongly SO 2} -containing gases which are more intense during the process step Sinter roasting of the layer are generated and which are fed to an operation for the production of sulfuric acid, as well as the SO ^ -lown gases that are generated during the one or more process stages in which a less intensive sinter roasting of the layer takes place, whereby it these latter gases are those which are returned to the sinter roasting process in order to be enriched _{with SO 2.} It should also be noted that in the method of the present invention, the gases resulting from the ignition process can be added either to the S0 ₂ -annen gases or the S02-rich gases or partly to the S0 _2- poor gases and partly to the SO ₂ -rich gases.

Air, oxygen-enriched air and oxygen come as oxygen-containing air that supports or sustains combustion Gases in question. Air and oxygen-enriched air are preferably used as such gases. The oxygen content of the combustion sustaining gas can range between 21 and 35% by volume, depending on the circumstances and more specific by the nature and moisture content of the mixture to be ignited. The flame temperature becomes approx

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1,000 ° increased to approximately 1,600 C and the S0 ₂ ~ content of the combustion gases increased from approximately 10% to approximately 28% by volume.

In particular, it is advantageous that sulfur is essentially completely burned in this flow of hot gases. Otherwise elemental sulfur would be able to deposit on the charge to be sintered.

To carry out this measure, it is advantageous if the flow of hot gases consists of one or more elementary flows that are generated by:

a) Atomization of liquid sulfur by means of pressurized, combustion-sustaining gas, around an elongated Jet stream of atomized sulfur una / ^ sustaining combustion or supporting gas,

b) in relation to this jet, a number of streams or currents which maintain or support the combustion Converge gas, these currents being a velocity component have in the direction of the propagation of the jet, so that a jet of atomized sulfur arises that contains a greater amount of combustion sustaining gas,

c) creating a circular flow of the sustaining the combustion Gas in a plane which is essentially perpendicular to the direction of propagation of the nozzle jet of method step b), this nozzle jet being circular through this Flow passes through it and being a swirled mixture of atomized sulfur and combustion sustaining gas is generated and

d) initiate or entrain the combustion by heating this mixture.

If the use of oxygen-enriched air proves advantageous, it is preferable to use this in the process

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• 3.

steps b) and c), whereas in step v a) Air is used.

It can be seen that the sum of the amounts of the combustion carrying or sustaining gas (converted into oxygen quantities) that are used in these three process steps, are such that they are sufficient to completely burn off the atomized sulfur without useless dilution of the Combustion gases takes place. These amounts are, for example, between 1.1 and 1.2 times the amount required to burn the sulfur stoichiometric amount.

The flow of hot gases used for ignition is advantageous either from an elementary stream which flows essentially horizontally into the aforementioned focus of inflammation or furnace is injected, or from two elementary streams running in opposite directions in substantially be injected into this furnace in a parallel manner in one and the same horizontal plane.

The present invention also includes a novel ignition device for the ignition furnace of the sinter roaster with endless grate. This device is characterized in that it has the following details:

a) at least one combustion chamber intended for sulfur, which is essentially cylindrical,

b) a sulfur atomizer, which is axially on or in a base the chamber is arranged,

c) a number of combustion maintaining gas nozzles arranged around the atomizer and on the axis aligned with the chamber and

d) a number of nozzles for combustion sustaining gas, tangential to the near the other base of the chamber Inner wall of the chamber essentially in such a plane

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which is perpendicular to the axis of the chamber, the combustion chamber with its mentioned other base is connected to the source or furnace of inflammation.

The axis of this chamber is preferably substantially horizontal and aligned perpendicular to the running direction of the grate.

The following description of a company or a device the invention is used to carry out the method according to the invention make it even easier to understand. In this description, reference is made to sintering in a Dwight-Lloyd apparatus, in which the downward train is present. This description is supported by the accompanying drawings, but it represents in no way constitutes a limitation of the invention.

Fig. 1 shows a schematic side view of a Dwight-Lloyd device ,

FIG. 2 shows an enlarged, horizontal section through the inflammation focus of the device, the section going along the line AA in FIG. 1 and

FIG. 3 shows a vertical section through the focus of inflammation, to be precise along the line B-B of FIG.

Reference is now made to FIG. 1. The Dwight-Lloyd device consists essentially of an endless grate 1, which is in the with the direction indicated by the arrow. It has a feeding device 2 with which a layer of the batch to be sintered is the grate 1 is fed. It also has an inflammatory device or an ignition focus or furnace 3 with which the layer is ignited or set on fire. It also has a suction box 4, with which the gases originating from the area of inflammation are collected will. With the provided suction boxes 5, the strong SC ^ - containing gases generated during the intensive roasting of the layer are collected. With the suction boxes 6 the at S0_- poor gases collected during the less intense roasting

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■ * "264A187

the layer can be generated. The suction box 5 are connected by lines 7 and a collector or a Saxnmel device 8 to a suction fan 9, which _{passes the gases containing a lot of SO 2} through a line which is not shown in the illustration. This latter line leads to a production facility for sulfuric acid, which is also not shown here. The suction box 4 from the area of the ignition furnace and the suction boxes 6 are connected by lines 10 and a collector 11 to a suction fan 12, which guides the gases resulting from the ignition and the gases poor in SO «through a line under the hood 13, this line is not shown here.

The ignition device is shown in FIGS. 2 and 3, which are now to be discussed 3, which essentially consists of the features listed below. She has a source of inflammation or furnace 14, which is the same as that used in the prior art described above. Next she has a cylindrical combustion chamber 15 horizontally disposed on a side post of the stove 14. In terms of of this arrangement, reference should be made in particular to the illustration in FIG. The ignition device 3 also has one Liquid sulfur atomizer 16, to which atomizer is supplied air and sulfur under pressure; the atomizer is (like also clearly visible from FIG. 2) arranged axially in the front, projecting part of the chamber 15. The combustion chamber 15, like the stove or oven 14, is lined with highly refractory bricks 17. On its front part it is (s. Fig. 2) aligned with four nozzles 18, with which combustion sustaining gas at an angle of 45 ° against the Axis of the chamber 15 can be directed. The two nozzles not shown in the figure lie in that plane of the chamber 15, which is perpendicular to the plane of the drawing. There is an opening 19 is provided, the insertion of a Start burner in the chamber 15 allows. Near the other end are two tangential, diametrically opposed to each other

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Nozzles 2o provided for combustion sustaining gas.

A method example carried out is specified in more detail below. With a device as described above, a batch based on zinc blende was sintered in an amount or rate of 40 tons per hour with a layer 12 cm thick and 200 cm wide. Sulfur was burned at a rate of 300 kilograms per hour, using approximately 1200 Nm3 of air per hour
became. Of this, 600 Nm3 were passed through the inclined nozzles and about 400 Nm3 through the tangential nozzles. Approximately 5.5 Nm3 of 4.5% SO ^ -containing gases were released per second
generated. However, under the same conditions,
the ignition known from the prior art generates approximately 5.5 Nm3 (only) 3.5% SO ^ -containing gas per second.

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Claims (1)

264418? - Vr- Expectations θ) A method for sintering a layer of sulfur-containing material on an endless grate, the layer being ignited by contact with a flow of hot gases below a source of ignition and the gases resulting from the ignition being _{added to the SO 2} -containing gases which during the subsequent sinter roasting of the ignited layer are produced and which are later used for the production of sulfuric acid, characterized in that the flow of hot gases takes place by burning elemental sulfur in oxygen-containing gas that supports or maintains the combustion. 2. The method according to claim 1, characterized in that the combustion-supporting or maintaining gas is air or with Is oxygen enriched air. 3. The method according to claim 1 or 2, characterized in that the combustion supporting or maintaining gas 21 to Contains 35% by volume of oxygen. 4. The method according to claim 1 or 3, characterized in that the flow of hot gases has a temperature between approximately 1,000 and approximately I.6008 C. 5. The method according to any one of claims 1 to 4, characterized in that that the flow of hot gases has an SO ^ content of up to about 1o and about 28% by volume. 6. The method according to any one of claims 1 to 5, characterized in ^ that the sulfur in the flow of hot gases is substantially completely burned. 7. The method according to any one of claims 1 to 6, characterized by the process steps: 709816/1034 a) atomization of liquid sulfur by means of pressurized gas which supports or maintains the combustion Generation of an elongated jet of atomized sulfur and combustion-sustaining gas, b) a number of streams combustion sustaining Gas, which (each) have a speed component in the direction of the propagation of the nozzle jet to make this jet converge, creating a jet of atomized sulfur with a greater content gas that carries or sustains combustion is produced, c) Generation of a circular flow from combustion-bearing or sustaining gas in a plane substantially perpendicular to the direction of propagation of the jet of the Process step b) is, wherein this nozzle jet passes through this circular flow and thereby a swirled one Mixture of atomized sulfur and the combustion-carrying or sustaining gas is generated and d) starting the combustion of this mixture by heating. 8. The method according to claim 7, characterized in that the flow consists of a single elementary stream which is in the is injected essentially horizontally into the focus or furnace of inflammation. 9. The method according to claim 7 or 8, characterized in that the Flow of hot gases consists of two elementary flows running in essentially opposite directions are injected parallel to each other in one and the same horizontal plane into the inflammatory focus or furnace. 1o. Method according to claim 7, 8 or 9, characterized in that that the gas carrying or maintaining the combustion is air in process step a) and is oxygen-enriched air in process steps b) and c). 09816/1034 11. Device for inflammation in a focus of inflammation or furnace (14), which is suitable for a device (Fig. 1) for sinter roasting with an endless grate (1), characterized by: a) at least one chamber (15) for the combustion of sulfur, which is essentially cylindrical, b) by a device (16) for atomizing sulfur, which is arranged axially in a base of the chamber (15), c) through a number of nozzles (18) for feeding the combustion sustaining gas, the nozzles being arranged around the means (16) for atomization and on the axis the chamber (15) are aligned and d) a number of nozzles (20) for feeding the combustion sustaining gas, which is close to the other base of the chamber (15) tangential to the inner wall (17) of the chamber (15) and are arranged essentially in a plane perpendicular to the axis of the chamber (15), the chamber (15) with this is connected to its other base with the ignition focus or furnace (14). 12. The device according to claim 11, characterized in that the axis of the chamber (15) is substantially horizontal and perpendicular to the direction of travel (arrow in Fig. 1) of the endless grate (1). 709816/1034