DE1408849A1 - Process for dephosphorization of iron melts and device for carrying out the process - Google Patents

Description

Applicant:. "lnjdwieaha.fen / Ph., October 50, 1969

Dr. Ing.Kurt Orths ^{P 5399 Ι / Αϊ} 403 Ratingen

Kastanienhof 1 patient note. P 14 08 849.4

Representative?

Patent attorneys

Dipl.-Ing. Adolf H. Fischer
Dipl.-Ing. Wolf-Dieter Fischer
Ludwigshafen / Rhine
Richard-Wagner-Strasse 22

Process for dephosphorization of iron clay and device to carry out the procedure

The invention "relates to a process for dephosphorization of iron melts, in the form of a refractory, preferably basic-lined reaction vessel, with as complete preservation of carbon as possible, with the supply of gaseous oxygen and with the supply of slag-forming and fresh and / or cooling, for the removal of Phosphorus particularly suitable solid mixtures, which advantageously contain SiOg, FeO, Fe ₂ O ^, AlgO ^ »CaO, MgO, Ka ₂ O, HnO or CaF ₂ , the temperature of the molten iron being at most 200 ° C, preferably 5 , 0 ° to 150 ° 0, is kept above the solidification temperature of the iron.

The invention consists in that Festatoifmisohungen, di «at working temperatures thin

- 2 - 009831/0054

-2- HQ88V9

become uninterrupted in or near the focal point and can be supplied in a regulated or controllable manner and simultaneously with the gaseous oxygen only superficially with the iron melt so in. Be brought into contact so that the slag that forms continuously overflows the sis melt and runs continuously to the same extent on the overflow of the reaction vessel.

According to the invention you can proceed so that for the purpose Control of the temperature and reaction process at

3 3

a supply of about 50 m to about 10 m gaseous oxygen per ton of iron to be treated about 2 up to 30 kg Peststoff mixture per 1 m ⁵ gaseous oxygen is added * wherein the supplied per unit time amount of gaseous oxygen during a Frisehbehandlung säglichst constant is maintained.

According to a further method step according to the invention, the procedure is that the slag-forming substances before or during the supply to the melt in such a ratio be mixed with each other so that at the specified temperatures a thin, reactive, Basic and oxidizing slag forms in and on the molten iron.

It seems advantageous to design the method in such a way that that the continuously flowing, still reactive slag on the grain size of the The pesticide mixture to be applied is crushed and as such or with a fresh pesticide mixture together again in a manner known per se as "Ent-" " phosphorous agent, is used; _ if necessary .. you can do so

009831/0084

H08849

method that the composition of the solid mixture In the course of the treatment of the ferrous iron is changed in such a way that the most phosphorus-rich iron melt at the beginning of the treatment a solid mixture with high proportions of closed-cycle slag is fed in during this Proportion of circulatory slag in the course of treatment the melt are reduced to such an extent that in the last third of the treatment no circulatory slag in the solid mixture more is included.

An apparatus for performing the method is, according to a proposal of the invention, that at least one independent line via deta vessel for the supply of gaseous oxygen, in particular in the form of an Eosen pipe, is provided » also that the vessel is in a rack or the like Is used that it can be tilted in relation to the normal position, that furthermore the solids container against its discharge is narrowed in such a conical manner that when discharging the layers of different- borrowed solid mixtures these individual layers only mix smoothly and that finally the Oxygen lance and the solids supply line in terms of their altitude and their inclination in relation to each other the vertical are adjustable. If necessary, this can be The end of the line feeding the solid mixture lies between the two ends of the Eosenrohr lance.

According to the present invention, it is proposed for the first time that of the melt uninterrupted and controllable

- 4 - 009831/0054

U08849-

to supply freshening and slack-forming solid muds, while at the same time at the point of impact This Sotffe on the melt or immediately next to it, the supply of gaseous oxygen on the one hand to a site ., stronger fresh effect with the well-known heating effect leads, so that the supplied solids © melt and react very quickly, on the other hand by a for any size or dimension of the metal surface adjustable. ble angle of incidence of the gas stream the slag to uniform circulating flow over the metal surface forces, and that the slag formed after absorption phosphorus can be continuously discharged at the overflow of the reaction vessel. The surprising effect the uninterrupted supply of the freshening and slag-forming substances and the compulsory uninterrupted overflow the slag with simultaneous supply of gaseous oxygen, has recently become "transitory" assigned to the principle mentioned. The admixture of circulatory slag to the solid mixture in the manner according to the invention contributes to that at every point in time of the treatment there is a concentration gradient between metal and slag that corresponds to the Nernstbähen Distribution Act or Henry's See Gösetz at the most favorable Reaction conditions with optimal utilization of the slag leads.

So far so far and in the following ^ remarks control on the one hand and control on the other hand, these terms should be understood as follows:

Regulation means intervening in the reaction process, if undesired processes are to be brought back to the normal process and control a predetermined Drainage circuit to keep the temperature and

009831 / O0S4

Η08849

■ ■ _ ■ - ■ ■ -

The course of the reaction is determined by the starting conditions, ζ. B, to be able to adapt certain initial Si and P contents.

As an example of a composition of the solids scavenging " let us mention:,;

Mill scale 33 #, quick lime 27 f * gout dust 24 #, soda 13 # and fluorspar 3 #. Soda can be completely or partially replaced by Glauber's salt but also by ground waste of technical glass, which means that small amounts of released carbonic acid can be eliminated and, at the same time, the properties of the slag can be improved if necessary. By appropriate adding z. B. the following composition of the mixture, which is compared to an analysis of the used slag;

SiO ₂ PeO Pe ₂ O ₃ Al ₂ O ₃ OaO MgO P ₃ O ₅ Na ₂ O MnO S

new 6.9129.6 12.2 3.65 29.9 1.97-11.3 0.22-2.74 - old 13.28 21.2 5.7 3.42 19.8 3.76 18.89 Gf / 2.22 ° »3 1.52 0.2

ZL Sm-p. '

new - 1150 ^
old 83 $> 1145 °

ZL = citrate solubility. Mp = melting point GV 9 loss on ignition

-As favorable /./ values, which, however, do not necessarily have to be adhered to Represent limit values, the following are to be considered:

009831/0054 - 6 -

Amount of slag based on
Amount of iron:

Amount of gaseous oxygen:

Amount of the pesticide mixture "based on simultaneously supplied gaseous Amount of oxygen:

Vi; Iron kg pesticide mixture / lfarO,

10 approx. 40 approx. 2.5 more common 15th approx. 35 approx. 4.3 ^ Working 20th ca * 30th approx. 6.7 y area 25th approx. 22nd approx. 11.4 y 30th approx. 15th approx. 20th

According to the information in the table above, the properties of the starting iron are determined with Driving slag quantities (controlling), e.g .:

With about 15 5 ^ slag and approx. 4 kg of pesticide mixture per Mm3 of gaseous oxygen

a) at low starting temperatures ratures (below 13000 c)

b) low initial Si and P levels
(Si <0.6 %, P ~ / 1.4? 0 -

c) Batches which may still contain approx. $ 0.5> P after treatment

d) high radiation losses due to small amounts of iron (/ - ^ 500 kg) large surface the melt, etc.

With about 25 5 ^ slag and about 11 kg solid mixture each Νπκ gaseous oxygen

at

a) higher starting temperatures (approx. 1350 ° C)

b) high initial Si and P contents

c) Batches that are largely to be dephosphorized (P <0.2 #)

d) small radiation losses due to larger quantities of iron (y 1000 kg), smaller ones

0 09831/005 A ^{01 area of} the melt etc. - 7 -

U08849

According to the temperature and reaction course of the Batch can do that during freshening or treatment Ratio of the amount of pesticides to the amount of gaseous substances Oxygen (regulating) can be changed, for example in order to counteract undesired reaction rates or reaction directions as early as possible is preferably done by changing the amount of solids. " d. H. the amount of gaseous oxygen is preferably kept constant during a treatment, to ensure the safety of the process and also to a large extent the carbon content of the melt to obtain.

The course of dephosphorization according to the present Process and the only very minor decarburization is shown in a diagram (FIG. 1) in comparison to the known fresh process. Of the The hatched area in this diagram (left in the picture) indicates the surprisingly favorable results of the method according to the invention.

The following is an example of hot metal treatment

A phoephorreichas starting pig iron is preferably converted into a Basically lined vessel filled with appropriate capacity. For this you can z. B. the Use the usual and always available pans in the shape of a cup with a capacity of around 500 kg or more. The pan can also, as already stated, with neutral or acidic Feed, e.g. with adhesive sand or the like. It is beneficial if the pans have the condition

009831/0054

-8- H08849

meet that the ratio of the diameter to the height is equal to or greater than 1. A device for Tilting the pan allows the most favorable height for the overflow of the slag to be set. It is further It is advantageous to choose the starting temperatures as low as possible, i.e. in the case of pig iron approximately between 1200 ° C to 1300 ° ö.

A mixture of powdery or granular solids is now applied to the surface of the molten iron supplied in one of the various types already proposed, whereby by the upstream dosing device an uninterrupted, adjustable or controllable addition of these solids during the entire duration treatment is possible.

The slag continuously overflowing becomes beneficial collected in two cinder pans, the one in the first half and the one in the second half of the Treatment accumulating slag is collected separately. The slag from about the first half of the treatment ' Process can be used for the production of fertilizers. The slag produced in about the second half is still reactive with regard to dephosphorization. One gets the latter slag on the grain size. the solid mixture and the container resp. return to the dosing device. This is the container from which the solids mixture over the Dosing device is continuously fed to the melt, fill so that the most phosphorus-rich iron melt, So at the beginning of the fresh treatment, a solid mixture with high proportions of already used and

- 9 009831/0064

recycled KreislauiVohlaclce from de? second Half of the treatment & procedure is supplied »This Proportions of circulatory slag are given by 'appropriate Arrangement in the solids container in the course of the treatment reduced to such an extent that approximately in the last third in terms of time treatment only contains unused substances in the pesticide mixture are contained and fed to the melt.

Further features of the invention emerge from the The following description of its exemplary embodiment in Connection with the drawing and the claims.

It shows, in schematiBchea sketches,

Figure i - a graph of results according to the inventive method,

FIG. 2 shows a small installation for carrying out the method in elevation, section according to FIG Line AB in Figure 3,

Figure 3 is a plan view of Figure 2 and

Figure 4 is a side elevation of Figure 2, section after the line ÖD in Figure 3.

On a gate-like tubular structure 1 is a container set up for the solid mixture. At the bottom of the Container 2 is a rotary valve 3 with stepless controllable drive connected. From lock 3 leads a chute 4 diagonally downwards, where it ends above a mobile pan 5 with a 6 hanger. The pan 5 is placed on a carriage 7, on which

Q09831 / Q0SA - 10 -

U08849

- ίο -

rear part, below the bottom of the pan 5 opposite the snout 9 a lifter 8 is arranged, which serves to tilt the pan a little. Before or below the snout 9 of the pan 5, a mobile Schlaokenpfanne 10 is set up, which is used to accommodate the Slag flowing continuously from the pan 5 is used and can be replaced at any time during the process.

Above the location of the pan 5, there is a further tubular arch construction 11, which is supported by two massive bearing blocks 12. If necessary, as indicated in the drawing, a kind of chamber 13 for receiving oxygen bottles 14 can also be connected to a bearing block 12, if one _ ~~~ * ~ _-. '.'_ does not want to supply the oxygen from a central oxygen system by means of pipelines, and if the system is not to be set up in a stationary manner. On the horizontal part of the tubular construction fan 11, the pipe 15 for the supply of oxygen is suspended, which is designed as a Y-pipe lance 16 above the pan 5. Ceramic tips 17 are cemented in to protect the Y-pipe 16 from heat damage. Via an angular drive 18 arranged in the pipe structure 11, a worm 19 and nut 20 provide the possibility of raising and lowering the oxygen pipe 15. Furthermore, the tubular structure 11 is tiltably connected to the bearing blocks and can be tilted up to 60 ° with the help of a worm drive 21 relative to the vertical. Thus, there is the possibility of approaching the Y-pipe lance 16 to the surface of the melt in the ladle 5 or from it

- 11 -

009831/0054

U088A9

remove and further -at the same time the angle under dam the escaping oxygen hits the surface of the melt. The lance will tilted so that the point of impact of oxygen gas on the surface of the melt (focal point) with the pivot point; practically the same as the lance.

The slide 4 »through the pesticide mixture on the As can be seen from FIG. 2, ends between the two ends 17 the Y-pipe lance 16. If necessary, you can also the slide 4- in its distance to the mirror of the Change the melt or its tendency to do so. Lance and slide are possibly covered by asbestos or the like protected from extreme heat and smoke.

It appears advantageous, as indicated in FIG. 3, to have the measuring and control devices next to one of the bearing blocks 12 to be arranged. There is z. B. with the help of a turbidometer 22 of the acid pressure off or you amount measured, measured with the aid of a weighing device 23 Solid additions displayed, including the container and the Accessories are suspended accordingly and finally the thermoelectrically or optically measured temperature of the Melt displayed 24 ·

As already mentioned, the device described is only given as an example Small system «In principle, however, you have all the parts required for any size of system includes.

- 12 -

9-831 / 0054

Claims (7)

U08849 claims 1) Process for dephosphorization of iron melts, in the refractory, preferably basic-lined reaction vessel, with as complete preservation as possible ■ of carbon, with the supply of gaseous oxygen and with the supply of slag-forming and freshening and / or cooling, pesticide mixtures particularly suitable for the removal of phosphorus, in which advantageously SiO ₂ , PeO, Pe ₂ O ₅ , Al ₂ O ₅ . , CaO, MgO, ITa ₂ O, MnO or CaP _{2 are} contained, the temperature of the post-iron melt being kept at a maximum of 200 ° C, preferably from 50 ° to 150 ° C, above the solidification temperature of the iron, characterized in that that solid mixtures, which become thin at the working temperatures, are fed continuously and controllably or controllably in or near the focal point and at the same time only superficially brought into contact with the molten iron with the gaseous oxygen in such a way that the calibrating slag continuously overflows the molten iron and runs continuously to the same extent on the overflow of the reaction vessel. 2) Method according to claim 1, characterized in that for the purpose of regulating the temperature and reaction course at a supply of about 50 nr to about 10 nr gaseous oxygen per ton treated iron about 2 to 30 kg of solid mixture per 1 r of gaseous oxygen are added, the amount of gaseous oxygen supplied in the unit of time during a Fresh treatment is kept as constant as possible. 009831/0054 New documents (Art. 7 § 1 Ab «. 2 No. 1 sentence 3 <3 * s '· ■■' - 13 - ' BATH 3) Method according to claim 1 or 2, characterized characterized in that the slag-forming substances to be supplied before or during the supply to the melt in such a ratio that a reactive, basic and oxidizing slag that is thinly fluid at the specified temperatures forms in and on the molten iron. 4 ·) Method according to one of claims 1 to 3, characterized characterized in that the continuously flowing, still reactive slag on the grain size of the to be dispensed, shredded and used as a refuse mixture those or with a fresh solid mixture is used together again in a manner known per se as a phosphorus agent. 5) Method according to claim 4, characterized in that that the composition of the solid mixture in the course of the treatment of the iron melt is changed that the most phosphorus-rich iron melt at the beginning of the treatment a solid mixture with high proportions of recirculating slag is fed, while these proportions of the circulating slag in the course of the treatment of the melt are reduced so far that im tentatively about the last third of the treatment no longer contain any circulatory slag in the solid mixture is. 6) Device for performing the method according to one of claims 1 to 5, consisting of a refractory lined, e.g. insulated vessel, - ^u "0Q9831 / QG BATH H08849 in particular a pouring ladle, a container with a dosing device for the Fes-Jstoffmlerung and Measuring and regulating devices for the amount of treatment agent to be supplied, as well as from MeS and Control devices for the temperature of the melt, characterized in that at least an independent line for the supply of gaseous oxygen, in particular in the form of one Y-pipe, is provided, further that the vessel od in a frame. Like. Is inserted so that it is tiltable in relation to the normal position that welters to be the pest container against? η discharge like this conically narrowed that when discharging superimposed different pesticide mixtures these individual layers are only sliding mix and that finally the oxygen lance as well as the pesticide supply line in their altitude as well as in their inclination to the vertical. are adjustable. 7) Device according to claim 6, characterized in that the end of the feeding the solid mixture Line lies between the two branches of the Y-pipe lance. 009831/0054 BATH ORIGINAL st- Lee rs et te