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WO2001051674A1 - Method for granulating liquid slags - Google Patents

Method for granulating liquid slags Download PDF

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Publication number
WO2001051674A1
WO2001051674A1 PCT/AT2000/000347 AT0000347W WO0151674A1 WO 2001051674 A1 WO2001051674 A1 WO 2001051674A1 AT 0000347 W AT0000347 W AT 0000347W WO 0151674 A1 WO0151674 A1 WO 0151674A1
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WIPO (PCT)
Prior art keywords
water
slag
granulating
pipe
tank
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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PCT/AT2000/000347
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German (de)
French (fr)
Inventor
Alfred Edlinger
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Holcim Ltd
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Holcim Ltd
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Priority to AU21263/01A priority Critical patent/AU2126301A/en
Priority to EP00984611A priority patent/EP1161567A1/en
Publication of WO2001051674A1 publication Critical patent/WO2001051674A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2/00Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
    • B01J2/02Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic by dividing the liquid material into drops, e.g. by spraying, and solidifying the drops
    • B01J2/06Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic by dividing the liquid material into drops, e.g. by spraying, and solidifying the drops in a liquid medium
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21BMANUFACTURE OF IRON OR STEEL
    • C21B3/00General features in the manufacture of pig-iron
    • C21B3/04Recovery of by-products, e.g. slag
    • C21B3/06Treatment of liquid slag
    • C21B3/08Cooling slag
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21BMANUFACTURE OF IRON OR STEEL
    • C21B2400/00Treatment of slags originating from iron or steel processes
    • C21B2400/02Physical or chemical treatment of slags
    • C21B2400/022Methods of cooling or quenching molten slag
    • C21B2400/024Methods of cooling or quenching molten slag with the direct use of steam or liquid coolants, e.g. water
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21BMANUFACTURE OF IRON OR STEEL
    • C21B2400/00Treatment of slags originating from iron or steel processes
    • C21B2400/05Apparatus features
    • C21B2400/066Receptacle features where the slag is treated
    • C21B2400/072Tanks to collect the slag, e.g. water tank

Definitions

  • the invention relates to a method for granulating liquid slags, e.g. molten blast furnace slag, in which the liquid slag is introduced into a water bath and on a device for carrying out the method.
  • liquid slags e.g. molten blast furnace slag
  • Molten blast furnace slag is usually produced at temperatures between 1350 and 1600 ° C.
  • cold water granulation is currently mostly used to achieve solidified slag particles, in which the liquid blast furnace slag is granulated with 6 to 12 m 2 of water per ton of slag.
  • the water used heats up to temperatures of around 85 ° C and is cooled down in cooling doors to temperatures below 40 ° C, whereby only the sensible heat of the water between around 40 and around 85 ° C is available as the cooling enthalpy ,
  • the water phase there is salting and, in part, evaporation of the water.
  • the aqueous phase must therefore be drained off at regular intervals and make-up water added.
  • the wastewater Due to the slag chemistry, the wastewater has relatively high pH values, with pH values of up to about 12 being observed. Such cooling water can therefore not be given to a receiving water without pretreatment, and it must therefore be neutralized and usually also additionally cooled. The suspended matter in the wastewater must also be sedimented.
  • the slag granulate discharged from such wet granulation has a residual moisture content of 8 to 24% by weight and must therefore be mechanically dewatered and thermally dried at a further cost.
  • the granulate is obtained with grain sizes between 10 and 1500 ⁇ as a relatively dense grain and has only low porosity, so that a subsequent further comminution process, and in particular especially a grinding process that is relatively energy consuming.
  • High amounts of hydrogen sulfide are obtained during the granulation, the H2S emission originating from a slag-water reaction and having to be eliminated by means of complex gas scrubbers.
  • calcium sulfide is converted with water to calcium oxide and hydrogen sulfide, which is present in the gas phase in a corresponding dilution with air.
  • the invention now aims to create a method of the type mentioned at the outset with which the cooling medium water can be used thermally more efficiently and at the same time H2S can be drawn off in a higher concentration.
  • the invention further aims to increase the slag and glass content and to improve the slag grindability compared to cold water granulation.
  • the method according to the invention essentially consists in that the cooling water is introduced at boiling temperature. By providing the cooling water at boiling temperature, the latent enthalpy of evaporation of the cooling water is available for rapid cooling, thereby maximizing the slag and glass content.
  • the granules surprisingly have a very low apparent density and float on the boiling water, whereby the slag grindability is significantly improved compared to grindability when using cold water granulation.
  • the granulate itself is discharged from the boiling water at a temperature which exceeds the boiling point of the water, the adhesive water during the granulation lataustrages already evaporates, so that a dry granulate is immediately formed. Since water is only discharged together with the granulate in vapor form, there is no waste water problem. Steam is then condensed and returned to the granulator together with make-up water to cover the water vapor losses.
  • the H2S formed in the slag-water reaction remains in the gas phase during the condensation of the water and is present here in a concentrated form, so that it can be worked up sensibly and economically.
  • the process according to the invention is advantageously carried out in such a way that the evaporated water is circulated after condensation and, after recirculation, is brought to the boiling point by controlled addition of slag or by introducing steam, the residence time of the slag granules in the boiling water being able to be reduced considerably.
  • it can advantageously be carried out in such a way that the boiling water is stirred during the granulation or is moved by blowing in steam. Due to the very short residence time of the slag granulate in the boiling water, the fine slag fraction practically does not hydrate. Due to the high water temperature, the solubility of H2S in boiling water is almost negligible.
  • the glass content of the coarse fraction is significantly higher than that of cold water granulation, the overall cement technology properties are improved, and it has been shown in particular that the early strength of corresponding mixed cements is almost 20% higher than the early strength of corresponding mixed cements, which is achieved using blast furnace granulated with cold water - slags are produced.
  • the boiling temperature can be adjusted in particular by means of the slag melt / water flow ratio so that the cooling water is always approximately at the boiling point.
  • the slag heat is sufficient, which is approx. 350 kW h thermal energy / t liquid slag.
  • Stirring the hot water by means of an agitator or by blowing steam leads to a further improvement in the heat transfer and at the same time to a reduction in the size of the granulate particles, which further maximizes the glass content.
  • H2S Due to the high concentration of H2S in the gas phase after condensation, sulfur can be recovered economically, as is possible, for example, with the Claus process.
  • the process according to the invention is therefore advantageously carried out in such a way that the H2S which accumulates in the gas phase above the condensing water from the circuit by chemical reaction, such as e.g. the Claus process is separated under oxidation to elemental sulfur.
  • sulfur is obtained from hydrogen sulfide, and in the Claus process, hydrogen sulfide is oxidized to sulfur in two stages. After a first oxidation of H2S to SO2, the SO2 formed can then react with further H2S to form elemental sulfur by means of a catalyst, such as a bauxite catalyst.
  • the sulfur obtained in this way is usually already very pure and the economics of the process result in particular from the relatively high sulfur-hydrogen concentration of the gas phase above the condensing steam.
  • the invention further relates to a device which is suitable for carrying out the method according to the invention.
  • the device has a pelletizing tank, with a pipe open on both sides being arranged at a distance from the bottom of the pelletizing tank.
  • the granulating basin contains the water bath into which the liquid slag to be granulated is introduced, whereby in the granulating basin a pipe open on both sides is arranged at a distance from the bottom of the granulating basin, the granulating basin and the pipe open on both sides are connected in the manner of communicating vessels are.
  • the open pipe protrudes from the water bath contained in the pelletizing tank.
  • the liquid slag is opened from the top Pipe introduced, the specific weight of the water bath enclosed by the pipe is reduced due to the heat and gas development, so that a buoyancy force arises within the pipe, which promotes the water bath contained in the pipe together with the granulated slag in height. In this way, the granulated slag can be conveyed above the level of the water bath located in the granulating basin, which considerably simplifies the discharge of the granulated slag.
  • the device is preferably developed in such a way that the tube is surrounded by a perforated sheet.
  • the granulated slag conveyed out of the pipe reaches the perforated plate and can be collected there and transported in a simple manner.
  • the design is advantageously designed such that an annular nozzle with nozzle openings directed towards the tube opening for water is arranged concentrically to the tube, furthermore the Ring nozzle can be connected to a drain in the bottom of the granulating tank via a pump.
  • a water jacket directed towards the pipe opening is then formed over the ring nozzle, with which the liquid slag can be introduced into the water bath.
  • the pump can be used to regulate the flow rate and thus to adjust the extent of the buoyancy within the tube by means of the pump with which the ring nozzle receives the water drawn from the outlet in the bottom of the granulating tank.
  • the slag 1 is a pelletizing tank, in which a pipe 2 open on both sides is arranged. There is a in the pelletizing tank Submitted water bath with boiling temperature, the water level is designated 3. The upper edge of the tube 2 protrudes above the water level 3, the granulated slag being conveyed onto a perforated plate 4 surrounding the tube 2 due to the buoyancy prevailing within the tube 2.
  • the slag which is denoted schematically by 5
  • the pipe 2 an annular nozzle 6 being arranged concentrically to the slag jet 5 and being drawn off from a drain in the bottom of the granulating basin 1 via a line 7 and a pump 8 Water is supplied.
  • the introduction of the slag leads to an evaporation of the boiling water and thus to a gas development, which causes a buoyancy in the direction of arrow 10 within the tube 2.
  • This buoyancy is used to convey the granulated slag to a level exceeding water level 3 and thus to facilitate the discharge of the granulated slag.
  • the constant escape of steam or boiling water from the tube 2 creates a circuit in which the water contained in the pelletizing tank 1 flows continuously into the area of the tube 2.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)
  • Treating Waste Gases (AREA)

Abstract

The invention relates to a method for granulating liquid slags (5), such as molten blast-furnace slag. The liquid slag is introduced into a water bath. The cooling water provided is at the boiling point.

Description

Verfahren zum Granulieren von flüssigen SchlackenProcess for granulating liquid slags

Die Erfindung bezieht sich auf ein Verfahren zum Granulieren von flüssigen Schlacken, wie z.B. schmelzflüssiger Hochofenschlacke, bei welchem die flüssige Schlacke in ein Wasserbad eingebracht wird sowie auf eine Vorrichtung zur Durchführung des Verfahrens .The invention relates to a method for granulating liquid slags, e.g. molten blast furnace slag, in which the liquid slag is introduced into a water bath and on a device for carrying out the method.

Schmelzflüssige Hochofenschlacke fällt üblicherweise bei Temperaturen zwischen 1350 und 1600° C an. Neben der Trockengranu- lation wird gegenwärtig zumeist eine Kaltwassergranulation zur Erzielung von erstarrten Schlackenpartikeln angewandt, bei welcher die flüssige Hochofenschlacke mit 6 bis 12 m^ Wasser pro Tonne Schlacke granuliert wird. Das eingesetzte Wasser erwärmt sich dabei auf Temperaturen von etwa 85° C und wird in Kühltür- en wiederum auf Temperaturen von unter 40° C abgekühlt, wobei als Kühlenthalpie somit nur die fühlbare Wärme des Wassers zwischen etwa 40 und etwa 85° C zur Verfügung steht. In der Wasser- phaεe kommt es zu einer Aufsalzung und teilweise zu einer Verdunstung des Wassers. Es muß daher in regelmäßigen Abständen die wässrige Phase abgeschlämmt werden und Zusatzwasser hinzugefügt werden. Bedingt durch die Schlackenchemie weist das Abwasser relativ hohe pH-Werte auf, wobei pH-Werte bis zu etwa 12 beobachtet werden. Derartiges Kühlwasser kann daher in der Folge nicht ohne Vorbehandlung einem Vorfluter aufgegeben werden, und es muß daher zwingend neutralisiert und meist auch noch zusätzlich gekühlt werden. Die Schwebstoffe des Abwassers müssen ebenfalls sedimentiert werden.Molten blast furnace slag is usually produced at temperatures between 1350 and 1600 ° C. In addition to dry granulation, cold water granulation is currently mostly used to achieve solidified slag particles, in which the liquid blast furnace slag is granulated with 6 to 12 m 2 of water per ton of slag. The water used heats up to temperatures of around 85 ° C and is cooled down in cooling doors to temperatures below 40 ° C, whereby only the sensible heat of the water between around 40 and around 85 ° C is available as the cooling enthalpy , In the water phase, there is salting and, in part, evaporation of the water. The aqueous phase must therefore be drained off at regular intervals and make-up water added. Due to the slag chemistry, the wastewater has relatively high pH values, with pH values of up to about 12 being observed. Such cooling water can therefore not be given to a receiving water without pretreatment, and it must therefore be neutralized and usually also additionally cooled. The suspended matter in the wastewater must also be sedimented.

Sowohl die Schwebstoffe als auch der hohe Salzgehalt des Ab- wassers sind keinesfalls umweltverträglich, sodaß die Entsorgung mit weiteren Kosten verbunden ist. Das aus einer derartigen Naßgranulation ausgetragene Schlackengranulat weist eine Restfeuchte von 8 bis 24 Gew.% auf und muß daher unter weiterem Kostenaufwand mechanisch vorentwässert und thermisch getrocknet werden. Das Granulat fällt mit Korngrößen zwischen 10 und 1500 μ als relativ dichtes Korn an und weist nur geringe Porosität auf, sodaß ein nachfolgender weiterer Zerkleinerungsprozeß, und ins- besondere ein Mahlprozess, relativ energieaufwendig ist. Je gröber das Korn, desto geringer ist der Verglasungsanteil , und es liegt insbesondere der Grobfraktionsanteil mit Korngrößen von über 600 μ zumindest teilweise entglast vor, wohingegen der Feinanteil aufgrund der relativ langen Verweilzeit im Wasser bereits teilweise hydratisiert vorliegt und in der Folge daher zementtechnologisch inaktiv wird.Both the suspended matter and the high salt content of the wastewater are in no way environmentally friendly, so disposal is associated with additional costs. The slag granulate discharged from such wet granulation has a residual moisture content of 8 to 24% by weight and must therefore be mechanically dewatered and thermally dried at a further cost. The granulate is obtained with grain sizes between 10 and 1500 μ as a relatively dense grain and has only low porosity, so that a subsequent further comminution process, and in particular especially a grinding process that is relatively energy consuming. The coarser the grain, the lower the proportion of glazing, and in particular the coarse fraction with grain sizes of over 600 μ is at least partially devitrified, whereas the fine fraction is already partially hydrated due to the relatively long residence time in the water and therefore becomes inactive in terms of cement technology ,

Bei der Granulation fallen hohe Mengen an Schwefelwasserstoff an, wobei die H2S-Emission aus einer Schlacke-Wasser-Reaktion stammt und über aufwendige Gaswäscher eliminiert werden muß. Bei dieser Schlacke-Wasser-Reaktion wird Kalziumsulfid mit Wasser zu Kalziumoxid und Schwefelwasserstoff umgesetzt, welches mit dem verdunstenden Wasser in der Gasphase in entsprechender Ver- dünnung mit Luft vorliegt.High amounts of hydrogen sulfide are obtained during the granulation, the H2S emission originating from a slag-water reaction and having to be eliminated by means of complex gas scrubbers. In this slag-water reaction, calcium sulfide is converted with water to calcium oxide and hydrogen sulfide, which is present in the gas phase in a corresponding dilution with air.

Die Erfindung zielt nun darauf ab, ein Verfahren der eingangs genannten Art zu schaffen, mit welchem das Kühlmedium Wasser thermisch effizienter genutzt werden und gleichzeitig H2S in hö- herer Konzentration abgezogen werden kann. Weiters zielt die Erfindung darauf ab, den Schlacken-Glas-Gehalt zu erhöhen und die Schlackenmahlbarkeit gegenüber einer Kaltwassergranulation zu verbessern. Zur Lösung dieser Aufgabe besteht das erfindungsgemäße Verfahren im wesentlichen darin, daß das Kühlwasser mit Siedetemperatur vorgelegt wird. Dadurch, daß das Kühlwasser mit Siedetemperatur vorgelegt wird, steht die latente Verdampfungsenthalpie des Kühlwassers zur raschen Abkühlung zur Verfügung, wodurch der Schlacken-Glas-Gehalt maximiert wird. Das Granulat hat überraschender Weise eine sehr geringe scheinbare Dichte und schwimmt auf dem siedenden Wasser auf, wodurch die Schlackenmahlbarkeit wesentlich gegenüber der Mahlbarkeit bei Verwendung von Kaltwassergranulation verbessert wird. Insbesondere gelingt es, die spezifische Mahlarbeit auf etwa ein Drittel der für das Mahlen von mit Kaltwasser granulierter Schlacke erforderlichen Werte zu senken. Das Granulat selbst wird mit einer die Siedetemperatur des Wassers übersteigenden Temperatur aus dem siedenden Wasser ausgetragen, wobei das Haftwasser während des Granu- lataustrages bereits abdampft, sodaß unmittelbar ein trockenes Granulat entsteht. Da Wasser gemeinsam mit dem Granulat lediglich in Dampfform ausgetragen wird, besteht auch kein Abwasserproblem. Dampf wird in der Folge kondensiert und gemeinsam mit Zusatzwasser zur Deckung der WasserdampfVerluste dem Granulator rückgeführt. Das bei der Schlacke-Wasser-Reaktion entstehende H2S verbleibt bei der Kondensation des Wassers in der Gasphase und liegt hier in konzentrierter Form vor, sodaß eine sinnvolle und wirtschaftliche Aufarbeitung gelingt.The invention now aims to create a method of the type mentioned at the outset with which the cooling medium water can be used thermally more efficiently and at the same time H2S can be drawn off in a higher concentration. The invention further aims to increase the slag and glass content and to improve the slag grindability compared to cold water granulation. To achieve this object, the method according to the invention essentially consists in that the cooling water is introduced at boiling temperature. By providing the cooling water at boiling temperature, the latent enthalpy of evaporation of the cooling water is available for rapid cooling, thereby maximizing the slag and glass content. The granules surprisingly have a very low apparent density and float on the boiling water, whereby the slag grindability is significantly improved compared to grindability when using cold water granulation. In particular, it is possible to reduce the specific grinding work to about a third of the values required for grinding slag granulated with cold water. The granulate itself is discharged from the boiling water at a temperature which exceeds the boiling point of the water, the adhesive water during the granulation lataustrages already evaporates, so that a dry granulate is immediately formed. Since water is only discharged together with the granulate in vapor form, there is no waste water problem. Steam is then condensed and returned to the granulator together with make-up water to cover the water vapor losses. The H2S formed in the slag-water reaction remains in the gas phase during the condensation of the water and is present here in a concentrated form, so that it can be worked up sensibly and economically.

Mit Vorteil wird das erfindungsgemäße Verfahren so durchgeführt, daß das verdampfte Wasser nach einer Kondensation im Kreislauf geführt wird und nach der Rückführung durch geregelte Schlackenzugabe oder unter Einleiten von Dampf auf Siedetemperatur gebracht wird, wobei die Verweilzeit des Schlackengranulats im Siedewasser wesentlich herabgesetzt werden kann. Um diese Verweilzeit weiter herabzusetzen, kann mit Vorteil so vorgegangen werden, daß das Siedewasser während der Granulation gerührt oder durch Einblasen von Dampf bewegt wird. Aufgrund der sehr kurzen Verweilzeit des Schlackengranulats im Siedewasser hydratisiert der Schlackenfeinanteil praktisch nicht. Aufgrund der hohen Wassertemperatur ist auch die Löslichkeit von H2S in Siedewasser nahezu zu vernachlässigen. Da der Glasgehalt der Grobfraktion wesentlich gegenüber einer Kaltwassergranulation höher ist, ergeben sich insgesamt verbesserte zementtechnologische Eigenschaften und es konnte insbesondere gezeigt werden, daß die Frühfestigkeit entsprechender Mischzemente um nahezu 20 % höher liegt als die Frühfestigkeit entsprechender Mischzemente, welche unter Verwendung von mit Kaltwasser granulierten Hochofen- schlacken hergestellt werden.The process according to the invention is advantageously carried out in such a way that the evaporated water is circulated after condensation and, after recirculation, is brought to the boiling point by controlled addition of slag or by introducing steam, the residence time of the slag granules in the boiling water being able to be reduced considerably. In order to further reduce this residence time, it can advantageously be carried out in such a way that the boiling water is stirred during the granulation or is moved by blowing in steam. Due to the very short residence time of the slag granulate in the boiling water, the fine slag fraction practically does not hydrate. Due to the high water temperature, the solubility of H2S in boiling water is almost negligible. Since the glass content of the coarse fraction is significantly higher than that of cold water granulation, the overall cement technology properties are improved, and it has been shown in particular that the early strength of corresponding mixed cements is almost 20% higher than the early strength of corresponding mixed cements, which is achieved using blast furnace granulated with cold water - slags are produced.

Die Siedetemperatur kann insbesondere durch das Verhältnis Schlackenschmelze-/Wasserfluß so eingestellt werden, daß das Kühlwasser immer ungefähr am Siedepunkt ist. Dazu genügt die Schlackenwärme, die ca. 350 kW h therm. Energie/t flüssiger Schlacke beträgt. Das Rühren des Heißwassers mittels eines Rührwerkes oder durch Einblasen von Dampf führt zu einer weiteren Verbesserung der Wärmeübergänge und gleichzeitig zu einer Verkleinerung der Granulatpartikel, wodurch der Glasgehalt weiter maximiert wird.The boiling temperature can be adjusted in particular by means of the slag melt / water flow ratio so that the cooling water is always approximately at the boiling point. The slag heat is sufficient, which is approx. 350 kW h thermal energy / t liquid slag. Stirring the hot water by means of an agitator or by blowing steam leads to a further improvement in the heat transfer and at the same time to a reduction in the size of the granulate particles, which further maximizes the glass content.

Aufgrund des nunmehr nach dem Kondensieren in hoher Konzentration anfallenden H2S-Gehaltes der Gasphase gelingt es hier, auf wirtschaftliche Weise Schwefel rückzugewinnen, wie dies beispielsweise mit dem Claus-Verfahren möglich ist. Mit Vorteil wird daher im Rahmen des erfindungsgemäßen Verfahrens so vorgegangen, daß das über dem kondensierenden Wasser konzentriert in der Gasphase anfallende H2S aus dem Kreislauf durch chemische Umsetzung, wie z.B. das Claus-Verfahren unter Oxidation zu elementarem Schwefel, abgetrennt wird. Beim Claus-Verfahren wird Schwefel aus Schwefelwasserstoff gewonnen, wobei im Claus-Verfahren Schwefelwasserstoff zweistufig zu Schwefel oxidiert wird. Nach einer ersten Oxidation von H2S zu SO2 kann in der Folge mittels eines Katalysators, wie beispielsweise eines Bauxit- Katalysators das gebildete SO2 mit weiterem H2S zu elementarem Schwefel reagieren. Der auf diese Weise gewonnene Schwefel ist in der Regel bereits sehr rein und die Wirtschaftlichkeit des Verfahrens ergibt sich insbesondere aus der relativ hohen Schwefel-Wasserstoff-Konzentration der Gasphase über dem kondensierenden Dampf.Due to the high concentration of H2S in the gas phase after condensation, sulfur can be recovered economically, as is possible, for example, with the Claus process. The process according to the invention is therefore advantageously carried out in such a way that the H2S which accumulates in the gas phase above the condensing water from the circuit by chemical reaction, such as e.g. the Claus process is separated under oxidation to elemental sulfur. In the Claus process, sulfur is obtained from hydrogen sulfide, and in the Claus process, hydrogen sulfide is oxidized to sulfur in two stages. After a first oxidation of H2S to SO2, the SO2 formed can then react with further H2S to form elemental sulfur by means of a catalyst, such as a bauxite catalyst. The sulfur obtained in this way is usually already very pure and the economics of the process result in particular from the relatively high sulfur-hydrogen concentration of the gas phase above the condensing steam.

Die Erfindung betrifft weiters eine Vorrichtung, welche für die Durchführung des erfindungsgemäßen Verfahrens geeignet ist. Die Vorrichtung weist ein Granulierbecken auf, wobei in Abstand vom Boden des Granulierbeckens ein beidseitig offenes Rohr angeord- net ist. Das Granulierbecken enthält hierbei das Wasserbad, in welches die zu granulierende flüssige Schlacke eingebracht wird, wobei dadurch, daß im Granulierbecken im Abstand vom Boden des Granulierbeckens ein beidseitig offenes Rohr angeordnet ist, das Granulierbecken und das beidseitig offene Rohr nach Art von kommunizierenden Gefäßen miteinander verbunden sind. Das offene Rohr ragt hierbei aus dem im Granulierbecken enthaltenen Wasserbad hervor. Die flüssige Schlacke wird von oben in das offene Rohr eingebracht, wobei sich das spezifische Gewicht des vom Rohr umschlossenen Wasserbades aufgrund der Wärme- sowie der Gasentwicklung verringert, sodaß innerhalb des Rohres eine Auftriebskraft entsteht, welche das im Rohr enthaltene Wasserbad gemeinsam mit der granulierten Schlacke in die Höhe fördert. Die granulierte Schlacke kann auf diese Art und Weise über das Niveau des sich im Granulierbecken befindlichen Wasserbades gefördert werden, wodurch das Austragen der granulierten Schlacke wesentlich vereinfacht wird.The invention further relates to a device which is suitable for carrying out the method according to the invention. The device has a pelletizing tank, with a pipe open on both sides being arranged at a distance from the bottom of the pelletizing tank. The granulating basin contains the water bath into which the liquid slag to be granulated is introduced, whereby in the granulating basin a pipe open on both sides is arranged at a distance from the bottom of the granulating basin, the granulating basin and the pipe open on both sides are connected in the manner of communicating vessels are. The open pipe protrudes from the water bath contained in the pelletizing tank. The liquid slag is opened from the top Pipe introduced, the specific weight of the water bath enclosed by the pipe is reduced due to the heat and gas development, so that a buoyancy force arises within the pipe, which promotes the water bath contained in the pipe together with the granulated slag in height. In this way, the granulated slag can be conveyed above the level of the water bath located in the granulating basin, which considerably simplifies the discharge of the granulated slag.

In bevorzugter Weise ist die Vorrichtung zu diesem Zweck derart weitergebildet, daß das Rohr von einem Lochbleck umgeben ist. Dadurch gelangt die aus dem Rohr geförderte granulierte Schlacke auf das Lochblech und kann dort gesammelt und auf einfache Art und Weise weiterverbracht werden. Um nun eine zu große Auftriebskraft innerhalb des Rohres zu verhindern, welche das Einbringen und Eintauchen der flüssigen Schlacke erschwert, ist die Ausbildung in vorteilhafter Weise so ausgebildet, daß konzentrisch zum Rohr eine Ringdüse mit zur Rohröffnung gerichteten Düsenöffnungen für Wasser angeordnet ist, wobei weiters die Ringdüse über eine Pumpe mit einem Ablauf im Boden des Granulierbeckens verbunden sein kann. Über die Ringdüse wird nun ein zur Rohröffnung gerichteter Wassermantel ausgebildet, mit welchem die flüssige Schlacke in das Wasserbad eingebracht werden kann. Über die Pumpe, mit welcher der Ringdüse das aus dem Ablauf im Boden des Granulierbeckens abgezogene Wasser zugeführt wird, kann die Fördermenge reguliert und somit das Ausmaß der Auftriebskraft innerhalb des Rohres eingestellt werden.For this purpose, the device is preferably developed in such a way that the tube is surrounded by a perforated sheet. As a result, the granulated slag conveyed out of the pipe reaches the perforated plate and can be collected there and transported in a simple manner. In order to prevent excessive buoyancy within the tube, which complicates the introduction and immersion of the liquid slag, the design is advantageously designed such that an annular nozzle with nozzle openings directed towards the tube opening for water is arranged concentrically to the tube, furthermore the Ring nozzle can be connected to a drain in the bottom of the granulating tank via a pump. A water jacket directed towards the pipe opening is then formed over the ring nozzle, with which the liquid slag can be introduced into the water bath. The pump can be used to regulate the flow rate and thus to adjust the extent of the buoyancy within the tube by means of the pump with which the ring nozzle receives the water drawn from the outlet in the bottom of the granulating tank.

Die für die Durchführung des Verfahrens geeignete Vorrichtung wird nun anhand eines in der Zeichnung schematisch dargestellten Ausführungsbeispieles näher erläutert.The device suitable for carrying out the method will now be explained in more detail with reference to an exemplary embodiment shown schematically in the drawing.

In dieser ist die Granuliervorrichtung dargestellt, welche erfindungsgemäß nach dem Prinzip einer Mammutpumpe arbeitet. MitIn this the granulating device is shown, which works according to the invention on the principle of a mammoth pump. With

1 ist ein Granulierbecken bezeichnet, in welchem ein beidseitig offenes Rohr 2 angeordnet ist. Im Granulierbecken ist ein Wasserbad mit Siedetemperatur vorgelegt, dessen Wasserspiegel mit 3 bezeichnet ist. Die Oberkante des Rohres 2 ragt dabei über den Wasserspiegel 3 hervor, wobei die granulierte Schlacke aufgrund des innerhalb des Rohres 2 vorherrschenden Auftriebes auf ein das Rohr 2 umgebendes Lochblech 4 gefördert wird. Zur Granulation der Schlacke wird die Schlacke, welche schematisch mit 5 bezeichnet ist, in das Rohr 2 eingebracht, wobei konzentrisch zum Schlackenstrahl 5 eine Ringdüse 6 angeordnet ist, welcher über eine Leitung 7 und eine Pumpe 8 aus einem Ablauf im Boden des Granulierbeckens 1 abgezogenes Wasser zugeführt wird. Der aus der Ringdüse 6 austretende Wasserstrahl, welcher durch die Pfeile 9 angedeutet ist und zur Öffnung des Rohres 2 gerichtet ist, erleichtert das Einbringen der Schlacke 5 in das sich innerhalb des Rohres 2 befindliche siedende Wasser. Das Ein- bringen der Schlacke führt zu einer Verdampfung des siedenden Wassers und somit zu einer Gasentwicklung, welche einen Auftrieb im Sinne des Pfeiles 10 innerhalb des Rohres 2 bewirkt. Dieser Auftrieb wird ausgenutzt, um die granulierte Schlacke auf eine das Wasserniveau 3 übersteigende Höhe zu fördern und damit das Austragen der granulierten Schlacke zu erleichtern. Wie schematisch mit den Pfeilen 11 angedeutet, entsteht durch das ständige Entweichen von Dampf bzw. siedendem Wasser aus dem Rohr 2 ein Kreislauf, bei welchem das im Granulierbecken 1 enthaltene Wasser kontinuierlich in den Bereich des Rohres 2 nachfließt. 1 is a pelletizing tank, in which a pipe 2 open on both sides is arranged. There is a in the pelletizing tank Submitted water bath with boiling temperature, the water level is designated 3. The upper edge of the tube 2 protrudes above the water level 3, the granulated slag being conveyed onto a perforated plate 4 surrounding the tube 2 due to the buoyancy prevailing within the tube 2. For the granulation of the slag, the slag, which is denoted schematically by 5, is introduced into the pipe 2, an annular nozzle 6 being arranged concentrically to the slag jet 5 and being drawn off from a drain in the bottom of the granulating basin 1 via a line 7 and a pump 8 Water is supplied. The water jet emerging from the ring nozzle 6, which is indicated by the arrows 9 and is directed towards the opening of the tube 2, facilitates the introduction of the slag 5 into the boiling water located within the tube 2. The introduction of the slag leads to an evaporation of the boiling water and thus to a gas development, which causes a buoyancy in the direction of arrow 10 within the tube 2. This buoyancy is used to convey the granulated slag to a level exceeding water level 3 and thus to facilitate the discharge of the granulated slag. As indicated schematically by the arrows 11, the constant escape of steam or boiling water from the tube 2 creates a circuit in which the water contained in the pelletizing tank 1 flows continuously into the area of the tube 2.

Claims

Patentansprüche : Claims: 1. Verfahren zum Granulieren von flüssigen Schlacken, wie z.B. schmelzflüssiger Hochofenschlacke, bei welchem die flüssige Schlacke in ein Wasserbad eingebracht wird, dadurch gekennzeichnet, daß das Kühlwasser mit Siedetemperatur vorgelegt wird.1. Process for granulating liquid slags, e.g. molten blast furnace slag, in which the liquid slag is introduced into a water bath, characterized in that the cooling water is introduced at boiling temperature. 2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß das verdampfte Wasser nach einer Kondensation im Kreislauf geführt wird und nach der Rückführung durch geregelte Schlackenzugabe oder unter Einleiten von Dampf auf Siedetemperatur gebracht wird.2. The method according to claim 1, characterized in that the evaporated water is circulated after condensation and after recycling is brought to boiling temperature by controlled addition of slag or by introducing steam. 3. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß das Siedewasser während der Granulation gerührt oder durch Einblasen von Dampf bewegt wird.3. The method according to claim 1 or 2, characterized in that the boiling water is stirred during the granulation or moved by blowing in steam. 4. Verfahren nach Anspruch 1, 2 oder 3, dadurch gekennzeichnet, daß das über dem kondensierenden Wasser konzentriert in der Gas- phase ausfallende H2S aus dem Kreislauf durch chemische Umsetzung, wie z.B. das Claus-Verfahren unter Oxidation zu elementarem Schwefel, abgetrennt wird.4. The method according to claim 1, 2 or 3, characterized in that the concentrated over the condensing water in the gas phase precipitating H2S from the circuit by chemical reaction, such as. the Claus process is separated under oxidation to elemental sulfur. 5. Vorrichtung zur Durchführung des Verfahrens nach einem der Ansprüche 1 bis 4 mit einem Granulierbecken, dadurch gekennzeichnet, daß im Granulierbecken in Abstand vom Boden des Granulierbeckens ein beidseitig offenes Rohr angeordnet ist.5. Apparatus for carrying out the method according to one of claims 1 to 4 with a granulating tank, characterized in that a pipe open on both sides is arranged in the granulating tank at a distance from the bottom of the granulating tank. 6. Vorrichtung nach Anspruch 5, dadurch gekennzeichnet, daß das Rohr von einem Lochblech umgeben ist.6. The device according to claim 5, characterized in that the tube is surrounded by a perforated plate. 7. Vorrichtung nach Anspruch 5 oder 6, dadurch gekennzeichnet, daß konzentrisch zum Rohr eine Ringdüse mit zur Rohröffnung gerichteten Düsenöffnungen für Wasser angeordnet ist. 7. Apparatus according to claim 5 or 6, characterized in that an annular nozzle with nozzle openings directed towards the pipe opening for water is arranged concentrically to the pipe. 8. Vorrichtung nach Anspruch 7, dadurch gekennzeichnet, daß die Ringdüse über eine Pumpe mit einem Ablauf im Boden des Granulierbecken verbunden ist. 8. The device according to claim 7, characterized in that the ring nozzle is connected via a pump to an outlet in the bottom of the pelletizing tank.
PCT/AT2000/000347 2000-01-13 2000-12-18 Method for granulating liquid slags Ceased WO2001051674A1 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1256633A3 (en) * 2001-05-10 2003-10-22 Tribovent Verfahrensentwicklung GmbH Process and apparatus for granulating molten materials such as e.g. liquid slags
WO2016145466A1 (en) 2015-03-13 2016-09-22 Radmat Ag Method and device for granulating molten material
WO2020124105A1 (en) 2018-12-18 2020-06-25 Radmat Ag Method for processing molten material

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GB991600A (en) * 1960-08-16 1965-05-12 Stewarts & Lloyds Ltd Improvements relating to the granulation of iron or slag
US3874737A (en) * 1973-08-18 1975-04-01 Hoesch Werke Ag Slag sand collecting hopper for a slag sand water mixture drainage silo
JPS5431097A (en) * 1977-08-13 1979-03-07 Sumitomo Metal Ind Ltd Production of metallurgical slag sand
DE3220624A1 (en) * 1982-05-03 1983-11-10 Klöckner-Humboldt-Deutz AG, 5000 Köln Device for continuous granulation of slags by means of coolant fluid
WO1999022031A1 (en) * 1997-10-29 1999-05-06 'holderbank' Financiere Glarus Ag Method for granulating and grinding molten material and device for carrying out said method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB991600A (en) * 1960-08-16 1965-05-12 Stewarts & Lloyds Ltd Improvements relating to the granulation of iron or slag
US3874737A (en) * 1973-08-18 1975-04-01 Hoesch Werke Ag Slag sand collecting hopper for a slag sand water mixture drainage silo
JPS5431097A (en) * 1977-08-13 1979-03-07 Sumitomo Metal Ind Ltd Production of metallurgical slag sand
DE3220624A1 (en) * 1982-05-03 1983-11-10 Klöckner-Humboldt-Deutz AG, 5000 Köln Device for continuous granulation of slags by means of coolant fluid
WO1999022031A1 (en) * 1997-10-29 1999-05-06 'holderbank' Financiere Glarus Ag Method for granulating and grinding molten material and device for carrying out said method

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1256633A3 (en) * 2001-05-10 2003-10-22 Tribovent Verfahrensentwicklung GmbH Process and apparatus for granulating molten materials such as e.g. liquid slags
WO2016145466A1 (en) 2015-03-13 2016-09-22 Radmat Ag Method and device for granulating molten material
WO2020124105A1 (en) 2018-12-18 2020-06-25 Radmat Ag Method for processing molten material

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ATA442000A (en) 2001-04-15
AU2126301A (en) 2001-07-24
AT408436B (en) 2001-11-26

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