FR2508062A1 - METHOD FOR MANUFACTURING CAST PARTS USING AS THE RAW MATERIAL, REDUCED IRON, MELTING FURNACE, AND BRIQUETTES AS MATERIALS FOR CASTING - Google Patents

Abstract

A.PROCESS FOR THE PRODUCTION OF CAST PARTS USING REDUCED IRON AS RAW MATERIAL. B. CHARACTERIZED IN THAT IT INCLUDES PHASES CONSISTING OF USING A TANK OVEN OF THE VERTICAL TYPE, LOADING A SOLID CARBON MATERIAL ON THE BASE-FIREPLACE OF THE TANK OVEN, BLOWING HOT AIR NEAR THE BASE -FIRE IN THE OVEN, AND LOADING REDUCED IRON AS A RAW MATERIAL IN THIS OVEN, THIS REDUCED IRON BEING MIXED WITH A SOLID CARBON MATERIAL, THE HEAT OF THE LOST GASES WHICH OCCUR BEING USED TO PREHEAT THE HOT AIR WHICH WILL BE BLOWN. C. THE INVENTION CONCERNS THE IRON FOUNDRY.

Description

Process for the production of castings using

  as raw material, reduced iron, melting furnace, and briquettes used as raw material

for the pours ".

  The invention relates to a method providing energy and material savings in the production of

  castings using reduced iron as a raw material

  it also relates to a melting furnace and a

  used as a raw material for casting, and which is produced by die casting of particles or

reduced iron powder.

  Compared with cast iron and steel, which is generally used as a raw material in the foundry, iron is reduced: it is generally in the form of small pieces, and it is porous like a sponge,

  so that its density is low and

  therefore, if it is desired to produce iron castings using reduced iron

  as a raw material, the cupola that is generally used

  to produce cast iron, is not suitable, because the reduced iron is in the form of small particles

  whose crush resistance is so low that the resistance

  the passage through the oven is increased by crushing them

  inside the oven: a large quantity of unreduced oxide slag contained in the reduced iron is formed, slags which are difficult to separate and eliminate

  which compromises the efficiency of the operation.

  If, to melt the reduced iron, an induction furnace is used, the wall of the furnace will be strongly eroded by the slag, which will cause a reduction in the efficiency of the fusion energy and cause disturbances in the operation of the furnace. merger It should be noted on the other hand that the reduced iron itself poses problems when

  wants to use it as a raw material for

  iron, for example significant variations in the

  molten metal composition, and an increased tendency towards oxy-

  dation. In recent times, the amount of reduced iron produced has been greatly increased worldwide, and it is considered that the reduced demand for iron for the production of cast iron will continue to increase as it meets desires of the industry

  the current foundry, which is trying to save money

  energy: its characteristics include, in fact, a lower energy expenditure for its production than

  for blast furnace melting, which is economically

  advantageously, a lower content of

  purities, and hope to use as raw material a particularly clean metal to give a cast iron containing

spheroidal graphite.

  As a result, research was conducted

  to allow a very wide use of reduced iron as

  first for the casting of coins.

  This research has focused on the following points: a) Investigations on reduced iron behavior when placed in different atmospheres in contact with

  a solid carbonaceous material and maintains temperatures at

  In particular, it has been brought into contact with atmospheres such as CO, air, and CO 2, and a solid carbonaceous material such as coke and graphite into pieces, and the like. This resulted in the following observations: (1) In a gaseous reductive atmosphere such as CO gas, even if the solid state is maintained at 1000 IC, a surface carbide is easily produced, which increases the carbon content; (2) In oxidizing atmosphere, mainly air, C 02, etc., an oxidation occurs from the surface, forming a thick oxidized layer on the whole periphery, a layer that can be seen if the we examine a section;

  (3) If the reduced iron is brought into contact with a car-

  solid bond, an oxidized coating is formed on the reduced iron surface, if the contact time is short or if the particle size of solid carbonaceous material is large; (4) If the reduced iron is melted in intimate contact with a solid carbonaceous material, the melting is complete when the temperature of about 1400 ° C. is reached, which means that the carburization takes place very rapidly from a solid carbonaceous material, subjected to a high temperature, greater than 10000 C, and it has been clearly realized that the unreduced oxides contained in the reduced iron have been

themselves reduced.

  (b) The proportion of mixed reduced iron was varied

  with cast iron or cast iron in the form of

  The mixture was melted in the induction furnace to produce iron castings whose nature was examined. The following findings were made:

  (1) The proportion of compounds can be reduced rapidly

  contained phosphorus and sulfur, particularly of the latter, by the addition of reduced iron, so that cast iron with a low sulfur content can be obtained; (2) The proportions of carbon, silicon and manganese, which have the greatest influence on the mechanical properties, are then adjusted so that the final proportions of these components are similar, and comparisons have been made. . The result has been that it has been found that the tensile strength can be increased by increasing the

reduced iron content.

  The object of the invention is thus to

  a process for producing improved castings using reduced iron as raw material,

  based on the basic research described above.

  The invention also has the following objects: a) to produce a melting furnace used for carrying out this production process, b) to make a briquette which will be used as a raw material for the castings, which can be loaded in one

  melting furnace for the production of castings in use

  using reduced iron, which effectively saves material and energy while producing improved quality castings,

  (c) to make a metal briquette used as a

  first for casting, in particular a briquette

  using reduced iron, this briquette wearing a coating

  oxidized on its surface to prevent oxidation of the briquette, d) to make a briquette used as a raw material for casting, which is molded under pressure so that its density reaches 4 g / cm 3 or more and that it has a suitable size and shape e) to make a raw material for castings which is

  prepared by shaping iron reduced to pellets or briquettes

  small or large, enclosed in a paper tube.

  The invention will be better understood with regard to

  the following description, examples of implementation and

  drawings, illustrating these examples, drawings in the

what

  FIG. 1 is a complete elevation view

  partly in longitudinal section of a furnace

  fusion used for carrying out the process according to the invention

  for the production of castings using reduced iron as raw material;

  FIG. 2 is a sectional view of a broken

  molded with an oxide coating, used as raw material for castings according to the invention,

  FIG. 3 is a sectional view of a machine

  first for castings which comprises reduced iron pellets, a ferroalloy, and a solid carbonaceous material, all enclosed in a paper tube,

  FIG. 4 is a sectional view of a machine

  first for casting which is prepared under the

  form of two reduced iron briquettes confined

in a paper tube,

  FIG. 5 is a view of a primary material

  casting material which is made in the form of a reduced cylindrical iron briquette inserted into a paper tube of the same length, and

  FIG. 6 is a view of a primary material

  for casting a solid carbonaceous material is charged between a reduced iron cylindrical briquette and a

  paper tube of the 9 m length.

  With the results obtained taking into account the basic research described above, the process for the production of castings using reduced iron as a raw material, according to the invention, is based on the following conditions: (1) As for the reduced iron smelting furnace, a shaft furnace built according to a vertical model

  suitable for reasons that will be described later.

  (2) Since the inside of the oven must be maintained in a

  essentially reductive atmosphere, we place in the

  focus a solid carbonaceous material, this carbonaceous material

2508062,

  solid is low sulfur coke, or if

  the pieces of graphite are removed and air is blown into the furnace near the lower hearth to allow the two reactions: C + 02> C 2 (exothermic reaction) Co 2 + C - * CO (endothermic reaction)

  occur in the oven, which ensures the proper heating

  necessary for the merger and thus ensures the reduction of

  reduced oxide content in reduced iron (3)

  the fusion of the reduced iron, the car-

  In order to achieve this, it is essential that the solid carbonaceous material and the reduced iron be

  intimate contact with each other in a solid state

  To achieve this objective, when the carbonaceous material is deposited on the low-focus and charges the raw material into the melting furnace, as described above, the reduced iron and the carbonaceous material are intimately mixed together. (4) Iron reduced which constitutes the raw material is usually in the form of small particles, as it

  described above, and the air pressure will rise abnormally

  if a current melting furnace is used.

  To reduce the resistance to the passage of air in the furnace, it is therefore necessary to place the exhaust gas outlet at a relatively low level for the construction of a shaft furnace (5). the furnace contains a large proportion of CO and

are at a high temperature.

  As a result, they are passed through a heat exchanger which is provided on its bottom with a combustion chamber in which secondary air is blown so as to cause secondary combustion.

  of this gaseous CO, the remaining heat and heat of com-

  lost gases being used to preheat

  supply air (6) As the proportions of silicone

  Since manganese and manganese are relatively low when compared with cast iron, it is desirable to provide a device for blowing silicon metal powder and manganese powder metal into the furnace (7). is in the form of fine particles, as described above, it is desirable that one installs a device that allows loading

continuous oven.

  When operating the improved apparatus built on the above conclusions, the following points should be taken into account:

  (1) To prevent the entry of sulfur components

  from the solid carbonaceous material placed on the hearth, and the solid carbonaceous material mixed with the raw material or reduced iron which is charged to the

  oven, at least half the amount of carbon

  Solids should be in the form of electrode graphite (2) If the carburation of the raw material or reduced iron takes place in the solid state, the melting temperature is lowered, so that the reduced iron melts at a

  relatively low temperature, which facilitates

  As a result, the particle size of the solid carbonaceous material which is charged to obtain a satisfactory mixture with reduced iron prior to charging is reduced. The process for the production of castings using reduced iron as a material

  first, which is achieved by these operations, and the

  The arrangement of these arrangements is a process for producing castings which compensates for the reduced iron configuration which makes it difficult to process from the point of view of use as a raw material, that is to say its disadvantage

  to be smashing, if we compare with the cast iron of

  furnace, while taking advantage of its characteristic

  to have a large surface area to facilitate

  of the solid phase carburation, which lowers the melting point and facilitates the operation of the furnace, increasing the advantage of having a small particle size, while extracting the lost gases from the

  inside the oven at a relatively low level to

  ter the resistance to the air that is blown into the furnace, taking advantage of the high content of these gases in CO gas for a secondary combustion intended to heat the supply air by increasing the thermal efficiency: one draws the advantage of using coke in small-sized particles and electrode graphite waste with low commercial value, as a solid carbonaceous material, the adjustment of

  molten metal content being easy.

  Figure 1 illustrates an embodiment

  of a melting furnace used in the process of the invention.

  The numeral 1 designates a furnace of fusion built on the model of a vertical shaft furnace, in which the material

  first, loaded by a loading opening 2, des-

  cinders in furnace 1 and is melted below a waste gas outlet 6, and is taken as metal

  melted by a taphole 3 Air from a breath

  22 arrives at the cold air inlet 9 in a sample

  7 of the radiation type and moves downwards by an interval between the outer wall of the heat exchanger 7 of the radiation type, and a

  plate 23 of heat transfer similar to a tube,

  As the heat exchange is effected, it is converted into hot air, which is then passed through a hot air outlet opening 8 through an air supply pipe into the furnace through which it enters the furnace. of nozzles 4

of this vertical shaft oven 1.

  On the other hand, the lost gases used to

  The exchange of heat is taken up by the orifice 6 of extrac-

  gases, and these gases at high temperature, containing a

  a large proportion of gaseous CO are burned by a burner

  10 and burned secondarily with the air fed through holes 11 of a secondary combustion chamber, which raises their temperature, then are subjected to a heat exchange: in the heat exchanger 7 of the radiation type, this that turns cold air into hot air Lost gases

  cooled by the exchange of heat are sent by a

  fice 12 of the exit of gases lost in the part of the lost gases which is raised by heating the layer of matter

  first, and finally escape through the chimney D'au-

  on the other hand, reference 13 indicates the ground level and 14

  indicates the level of a second floor.

  The briquette used as raw material for the casting according to the invention is made of small

  particles or metal powder with which we have

  if necessary, change small particles of a solid carbonaceous material and / or a mineral binder, the mixture being

  die-cast in shape blocks and appropriate dimensions

requested.

  For example, in a melting furnace for the production of castings using reduced iron as raw material, a small proportion is added.

  a mineral binder such as sodium silicate, in the same way as

  first or reduced iron, and small particles of a solid carbonaceous material as fuel, and

  it is intimately mixed and molded under pressure in lighter-

  suitable size which is loaded into the oven of

  melting, producing then castings of good quality

  while saving material and energy.

  As described above, the reduced iron, when compared with cast iron, is generally in the form of small blocks, has a spongy appearance, is porous and has a low bulk density, so that its specific surface area is large. Consequently, when heating reduced iron in an oxidizing atmosphere, a rapid oxidation from the surface occurs, but

  in a reducing atmosphere, under CO for example, it is

  easy to carburize, from the surface, which increases the carbon content. In addition, if this iron is heated in contact with a solid carbonaceous material which has been ground into small particles, the carburization is very easily carried out.

  1000 'C from this carbonaceous material.

  This advantage is also obtained that this process lowers the melting point of the reduced iron, the melting being

  complete at 14000 C, which saves energy.

  In the production of castings using

  reduced iron as a raw material based on the above, coke fines are used rather than

  to grind large blocks of coke to serve as car-

  so that the energy that would have been used for the spraying is spared. Moreover, the coke fines

  which are a by-product of the production of coke by

  coal burning in a gas or coke plant are of little commercial value and are rather troublesome,

  so that the use of coke fines is very

  desirable from the point of view of economy of matter.

  On the other hand, in order to maintain the level of molten metal that can be taken from the oven, it is not

  It is not necessary for the operator to add the proportion of

  the raw material of the mixture: the raw material

  age in the melting furnace is adjusted in proportions

  as they correspond to the quality of the parts

  which must be produced in sufficient quantity, and it goes without saying that in order to

  air in the uniform melting furnace and

  keep constant, it is very advantageous to prepare briquettes by molding them with dimensions and shapes

constant.

  When molding, we add to the material a

  a suitable amount of a binder such as silicate

  dium, and if we have to add another metal, we can

  add powder of this metal, for example fetrosiline

  or ferro-manganese; after mixing well, we

  will proceed to the pressure molding of the mixture

  the type and size of the briquettes, it becomes possible to adjust the ventilation sufficiently

the melting furnace.

  If the melting furnace is charged with

  briquettes intended to be used as a raw material

  first for castings, and prepared by mixing

  small particles of reduced iron and small particles

  carbonaceous material, for example coke fines or graphite particles with a small proportion of a mineral binder, for example sodium silicate added thereto, and molding the mixture to forms and suitable dimensions, the carburization takes place in the solid phase, which lowers the melting point and facilitates the melting, while obtaining uniform ventilation, so that the red-heated layer is made uniform

  and the operation is stabilized.

  -Thus the briquette can be used as raw material for casting parts that will be of good quality while ensuring a saving in materials and energy.

  On the other hand, if the embodiment

  above is further improved by forming an oxide coating

  on the briquettes, one will obtain other advantages.

  These advantages are described with reference to

  an embodiment illustrated in Figure 2.

  In Fig. 2, numeral 15 denotes a reduced iron briquette produced by die casting of a reduced iron mixture in the form of particles or powder, carbonaceous material into small particles, and

  a small proportion of inorganic binder such as silicon

  sodium carbonate, the briquette being molded with

  The number 16 indicates a mineral oxide applied to the surface of the reduced iron briquette, which may be a glass, in the form of particulate matter.

  or powder, this mineral oxide melting at a temperature of

  less than the melting point of the reduced iron briquette This material which can be fused to the reduced iron briquette is applied thereto with a mineral binder such as sodium silicate, which forms on the iron briquette reduces 15 a revatement

  mineral oxide 16 consisting mainly of glass.

  If this reduced iron briquette is melted, for example, in an induction furnace, the mineral oxide on the surface melts at about 8000 C to form a molten glass coating, with the result that

  the reduced iron briquette is completely isolated from the

  ambient atmosphere, which prevents oxidation when heated, and there is a reduction of iron oxide

  thanks to the solid carbonaceous material, mixed in

  reduced iron, which melts at about 14000 C to give molten iron Thus, after this fusion, the glass in the state

  melted material that formed the coating floats on the iron

  because of the difference in their specific weights,

  thus isolating the reduced iron and the atmosphere from each other.

  ambient temperature, and avoiding the oxidation of molten iron.

  Figures 3 to 6 show raw materials

  for casting according to other embodiments of the invention.

  the provisions made are as follows: In Figure 3, the figure 17 indicates

  reduced iron pellets which may be small in size

  in reduced iron briquettes formed into molds.

  The figure 18 indicates a paper tube made of inexpensive kraft paper coiled by adhering with a mineral adhesive such as sodium silicate, the outer surface of which is paper tube being coated with a heat-resistant mineral paint to prevent the paper tube from burning easily. The number 19 indicates a ferroalloy and indicates a solid carbonaceous material. The raw material for castings shown in FIG.

  thus a mixture of pellets 17 of reduced iron, ferro-

  alloy 19, such as ferro-silicon, added to adjust the composition of the cast iron, and a solid carbonaceous material, such as coke fines to fill the voids between the pellets 17 and the ferroalloy 19, the tube of

  paper 18 enclosing this mixture The raw material for cou-

  thus formed avoids oxidation in the furnace of the reduced iron and the alloying element such as Si,

and increase the yield.

  In Figure 4, we see two briquettes 21

  of reduced iron, molded into cylindrical briquettes and

  buttocks that are inserted into a paper tube

  whose dimension corresponds to the external diameter of the

  the opposite ends of this paper tube being

  With the raw material for castings thus formed,

  When the paper tubes 18 are subjected, when they burn in the furnace, to incomplete combustion, the reduced iron briquettes are maintained in a reducing gas atmosphere during melting, so that the oxidation at

  the solid state before fusion is avoided and the

  In addition, the briquettes are pro-

  The result is that the apparatus for molding the briquettes does not need to be very powerful, and it is possible to use briquettes having a high temperature. low crush resistance that

  can be produced with a low cost briquette machine

  high productivity, such as a roller type machine. Moreover, in molded briquettes containing

  a solid carbonaceous material and an alloy adjusting the composition

  position, or in large briquettes, add a mineral adhesive, such as sodium silicate to give

a suitable resistance.

  FIG. 5 shows a raw material for melting in which a paper tube 18 whose size corresponds to that of the outside diameter of a reduced, cylindrical iron briquette 21 is cut to the length of the cylinder of the briquette which is pushed to the inside of this tube, while in FIG. 6, the paper tube 18 of FIG. 5 has a larger dimension which exceeds the outside diameter of the briquette, and is loaded with

  in the vacuum that separates the paper tube 18 from the lighter-

  In FIG. 5, the crushing is avoided and the briquette is protected against oxidation in the solid state until it is melted, whereas in FIG. Solid carbonaceous material charged around the briquette further increases this effect.

  It is also possible to increase the resistance

  fire the paper tube by mixing a powder of

  refractory material in the mineral adhesive or in the paint

  mineral ture used in the production of the tube

of paper.

  Since the raw material for casting according to the invention is enclosed in a paper tube, as described above, the content of the raw material briquette can be adjusted very easily by choosing the quality of the paper, which constitutes

  another effect in addition to those described above.

  The effects of this embodiment will be

* now described based on test results.

  Table 1 below shows the relationship between the

  reduced iron content in the mixture and the proportion of slag formed as found when

25080-62

  cast iron and iron reduced in an induction furnace to

  high frequency The use of briquettes according to the

  vention suppresses the oxidation of reduced iron: the iron oxide present in the reduced iron is reduced by the carbonaceous material introduced into the briquettes, and the proportion of slag formed decreases as indicated by the dashed line

of the graph.

Table I:

  The ratio between the proportion of iron reduced in the mixture and the proportion of slag formed in a mixture

  melting operation using a high frequency furnace

  accordingly. o ri o c> U o TO 4> -d 'r 4 vo o a B': Notes A B: Indi- _

40 60 80 100

  Reduced amount of iron in the mixture,% Amount of slag formed (calculated value) in the case o Fe 0 existing in the reduced iron is reduced to%. A C: Quantity of slag formed (calculated value) in the

  o Fe O existing in the reduced iron is none

reduced.

  In these calculations, the quality of slag formed

  by attacking the oven wall and other similar

  This does not matter and the amount of slag formed when no reduced iron is mixed is taken as zero. In addition, the oxide coating as described above may be applied to other briquettes

  that those who use iron reduced in the mode of

above.

  Thus, it is possible to apply on the over-

  face of a die cast briquette with particles

  or a powder of a metal, with the addition of a binder if necessary, a mineral oxide that will melt and adhere to the metal briquette, using a mineral adhesive such as sodium silicate, which makes it forms an oxide coating on the surface of the briquette: this coating serves to prevent the oxidation of the briquette if

  stores it for a long time, or during the fu-

  From this briquette, the coating will first melt to form a molten oxide coating on the surface of the briquette, isolating it from the ambient atmosphere so as to avoid oxidation of the metal of this briquette,

  which improves the efficiency and effectiveness of

the operation.

  As for the method of using reduced iron as a raw material for casting in a more advantageous manner, this reduced iron in the form of pellets usually having a density of 4 g / cm or less may or may not

  to be crushed, in common with small particles of a

  carbonaceous solid and a mineral binder and be molded under pressure with dimensions and a suitable shape, so that the density reaches above 4 g / cm 3

  described below is the production of coin

  iron using reduced iron briquettes.

  Firstly, reduced iron pellets having a density of 2 to 3 g / cm 3 are finely ground to

3 mm and less.

  The energy required to crush the reduced iron pellets is only 1.2 to 1.5 KWH / T if 80% of these pellets are 9 mm or less and must be ground so that 80% is 2.5 mm or The reduced iron thus milled can be molded under pressure as such into

  briquettes or, if necessary, can be added

  solid carbonaceous material particles such as electrodes graphite waste and a mineral binder such as sodium silicate, and then mold this mixture under pressure.

  The mixture of solid carbonaceous material with

  is carried out when it is necessary to reduce the unreduced iron oxide present in the reduced iron and to

  to fuel the latter because of the inadequacy of its

  carbon neur If graphite waste is used

  electrodes as a solid carbonaceous material, its low tendency

  In the process of absorbing sulfur, a low-carbon molten metal is obtained, so that if a spherolding treatment is applied to this metal, a spheroidal graphite iron can easily be obtained.

  without any desulphurization being necessary.

  The purpose of adding a binder is to avoid

  the crumbling of the briquettes, because the moldability

  Briquettes are low if a car-

  solid bonée For example, the use of a mineral binder

  such as sodium silicate makes it possible to produce a

  In addition, if this inorganic binder, for example, sodium silicate, is added in a proportion of 6%, the amount of slag formed is 30% or less of the added amount, i.e. 8% or less of the total amount of charges; as a result, the amount of slag is low and it can be eliminated, so

  that there is no danger of lowering the quality.

  When the briquettes are molded under pressure so that their density is 4 g / cm or

  moreover, the porosity is diminished, and also the specific surface

  fic; therefore, even if they are kept at high temperature in the furnace, the loss due to oxidation is low, the melt yield is high and the amount

  of slag formed due to oxidation is of little importance.

  In addition, bricklaying greatly increases the resistance

  The reduced density of the reduced iron increases, so that the briquettes will not break and form powder during the manipulations As the apparent density of the reduced iron increases, there is no lowering of the melting speed when In addition, since these briquettes are molded so as to be of suitable size to be used as filler in a cupola, there is no danger that the

  resistance to the passage of air in the oven increases.

  The effects of this embodiment are de-

  below, based on the results of the tests

performed.

  The following tables show the ratio

  the amount of reduced iron mixed and the resistance to the passage of air in the furnace, the melt yield, and the amount of slag formed, respectively, as found when one melted in a cupola cast iron

  and reduced iron It has been found that the use of

  reduced iron quilts according to the invention, if we compare

  with the use of pelletized iron, the result is

  a decrease in resistance to passage through the furnace and a decrease in oxidation which, in turn, results in an increase in yield and a decrease in

  slag formation In addition the use of a bromine

  made from a mixture of reduced iron and

  Electrode graphite results in a further decrease

  slag formation, all non-ferric oxide

  reduced in the reduced iron being essential-

  In addition, the reduced proportion of iron entering the mixture and the amount of slag formed, as well as the melt efficiency observed when melting in a high-frequency induction furnace With a mixture of cast iron and a reduced iron mixture, it can be seen that the use of a reduced iron briquet alone eliminates the oxidation of this reduced iron, decreases the quantity of slag formed and improves the yield at the same time.

reduced iron melting.

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  Air pressure dal S the cylinder to veit during operation

Pel t -

s o Briq ette /) - Pellet _

____ __ __ __ __

Presion of air in the

Wind chiller at temperature

  _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ the oven (Air pressure in the wind cylinder)

  in a merge operation in the cupola.

o N 200 -P e

I 1160

  o H. <f C of 80 P. ' Table 3: Relationship between the proportion of iron reduced in the

  mixing and melting performance in an

melting ration in the cupola.

  *, r. The proportion of reduced iron in the mixture,% AB: Quantity of slag formed (calculated value) if the FeO present in the reduced iron has been reduced to 100% AC: Amount of slag formed (calculated value) if the Fe O present in the reduced iron is in no way reduced. In these calculations, the amount of slag formed due to coke ash

  and limestone is included.

  B 0 O Reduced iron proportion in the mixture,% Table 4: Ratio between the proportion of reduced iron in the mixture and the amount of slag formed in the mixture

  the melting operation in the cupola.

  oo Xo) co> o tkt o cl <n Id Qi -> o 4- a - (O to -H oc> <nc> e <ne I o ol M 0) $ 4 cd Iz ta u 4 J Ol lo TABLE 5 Ratio between the proportion of reduced iron in the mixture and the proportion of slag formed in the high frequency melting furnace. Quantity of slag formed in relation to the quantity of iron

___ reduced loaded.

  Quantity of slag formed (calculated value) according to the invention Quantity of slag formed relative to the quantity loaded

40 60 80 100

  Reduced amount of iron in the mixture (%> x O a) -P H M -I O to O (ritr O a) (nrd 4 J O

- '4-I

  4-P 4 J j -H. 4 r-P r. (cd a> ri o c> 4-Ie cd a> s-0 o Il-a) - s-i o - '. 4-I tr. A% J Notes A B: Quantity of slag formed (calculated value) if Fe O present in reduced iron is reduced to%, A C: Quantity of slag formed (calculated value) at

  o Fe O present in the reduced iron is not

reduced.

  In these calculations, the amount of slag due to the attack of the furnace wall or other causes is not included, and the amount of slag formed when there is no reduced iron in the

  mixture is taken as zero value.

Table 6:

  Ratio between the reduced iron content in the mixture and the melt yield in a

  high frequency fusion operation.

  Efficiency at fusion if we put inventiol into practice

0 20 40 60 80 100

  Reduced amount of iron in the mixture,% o <a rd G> -'J G> G> e c G> As described above, according to

  embodiment of the invention, it is possible to reduce

  the oxidation of iron reduced during fusion, and the increase

  Merging performance and reduced slag formation greatly improve the efficiency of the operation, increasing the value of reduced iron as a raw material for the production of castings. As has been described, according to the invention, the use of reduced iron, which meets the needs of the foundry industry in the current research

  savings in materials and energy.

Claims (6)

A process for the production of castings using reduced iron as raw material, characterized in that it comprises the steps of using a vertical type of shaft furnace, charging a solid carbonaceous material on the low-focus of the tank furnace, blowing hot air near this low-fire in the furnace, and charging reduced iron as raw material in this furnace, this reduced iron being mixed with a solid carbonaceous material, the heat of the gases lost occurring that is used to preheat the hot air that will be blown. A process as claimed in claim 1, characterized in that the heat of the lost gases is collected in the vicinity of the low fire, above the location where hot air is supplied. Process according to any one of claims 1 and 2, characterized in that the heat of the secondary combustion of the CO gas contained in the lost gases is used as the heat of these lost gases. Process according to any one of claims 1 to 3, characterized in that the solid carbonaceous material is low sulfur coke. Process according to any one of claims 1 to 3, characterized in that the solid carbonaceous material is graphite. Process according to any one of Claims 1 to 3, characterized in that at least half of the amount of solid carbonaceous material is electrode graphite. Process according to any one of claims 1 to 6, characterized in that silicon metal, or manganese metal, is blown into the shaft furnace.   80) Melting furnace for producing castings using reduced iron as a material   first, according to the method of claim 1,   characterized in that it comprises a main body consisting of the construction of a vertical shaft furnace, members for contacting a solid carbonaceous material with the raw material or the reduced iron, this material being arranged on the bottom focal point of the main body, hot-air blowing and hot-air units, arranged in the vicinity of the main body's low-focal point, and hot-air preheating organs from the supply members using the heat of the lost gases resulting products of the heating action hot air.   ) Melting furnace according to claim 8, characterized in that the waste gas recovery port is placed in the vicinity of the low-focus, above the supply members.   ) A melting furnace according to one of the   8 and 9, characterized in that the   heating elements for the secondary combustion of the CO gas contained in these lost gases and radiation-type heat exchange members for extracting the heat of combustion produced in these gases;   combustion elements to ensure preheating.   11) Briquette for use as a material   first for the production of castings according to the   1, characterized in that it is formed by die casting of a metal into small particles   dimensions in an appropriate form and dimension.   120) Briquet according to claim 11,   characterized in that the metal is iron in the reduced state.   Briquet according to Claim 12, characterized in that a material is mixed with the metal   carbonaceous solid before molding under pressure.   140) Briquette according to any one of   Claims 13 to 13, characterized in that   before molding under pressure, a mineral binder ral -   Briquet according to Claim 13,   characterized in that the solid carbonaceous material is   staggered by coke fines. Briquet according to Claim 14, characterized in that the inorganic binder is sodium silicate. ) Briquette according to any one of   claims 11 to 14, characterized in that it mixes powder of another metal.   18) Briquette according to any one of   Claims 11 to 17, characterized in that the surface   of this briquette is provided with a coating of   neral in fine particles intended to melt at a temperature   less than the melting point of the briquette.   19) Briquet according to Claim 18, characterized in that, if this coating is carried out,   the mineral oxide is bonded with a mineral adhesive.   20) Briquette according to one of the claims   18 and 19, characterized in that the inorganic binder is sodium silicate.   21) Briquette according to any one of   Claims 12 to 14, characterized in that the density is 4 g / cm 3 or more.   220) Briquette according to any one of   Claims 11 to 14, characterized in that the lighters   are shaped like large cylinders and are locked up one or more in a paper tube.   230) Briquettessextending any of the   claims 14 to 14, characterized in that they have the   cylinders and are enclosed in a paper tube whose two ends are open, so as not to   leave empty on the side surfaces of these lighters-   your. 24) Briquette according to claim 23, characterized in that the solid carbonaceous material is introduced into a space left between the briquette and the tube of paper.   250) Briquette constituting a raw material   for the production of cast iron parts, according to the   cation 24, characterized in that enclosed in a paper tube are pellets of reduced iron, or iron reduced to fine particles, shaped into briquettes, together with a small proportion of solid carbonaceous material and   with an alloy for adjusting the composition.