FR2626008A1 - PROCESS FOR OBTAINING FERROSILICIUM IN A HOME ENERGY UNIT - Google Patents

Abstract

The invention relates to a process for obtaining ferro-silicon in a furnace energy unit using, as fuel, carbonaceous materials, the slags of which contain iron oxides in a proportion of 10 to 22% by weight. According to the invention, a slag bath is created in the home energy unit, a jet of hydrocarbon fuel is brought on its surface, by heating the slag bath to a temperature of 1,700 to 1,800 degrees. (s) C, by bringing, simultaneously with the hydrocarbon fuel, pulverized products resulting from the combustion of carbonaceous materials, and the ferrosilicon is isolated from the slags which are formed during the burning of the fuel. The invention applies in particular to thermal power stations and to the steel industry.

Description

The present invention relates to thermal power plants

  and the steel industry, and more particularly it aims at a process for obtaining ferrosilicon in a unit.

home energy.

  The invention can be implemented to obtain ferrosilicon in focal energy units, parallel to the production of electrical energy, thereby minimizing waste from

of this last operation.

  We know that the quality of solid fuels

  energy vocation is depreciating everywhere in the world.

  This is due to the increase in the relative share of

  fuel with low calorific value, mined or-

  green. The mechanized extraction of thin layers of coal in the mines and the high proportion of gangue in coal from the quarries are responsible for the high ash content of the coals and their low calorific value. Non-combustible minerals mixed with solid fuels and consisting of not more than 50% by weight of silicon oxides, not more than 27% by weight of aluminum oxides and 10 to 20% by weight of iron oxides, completely pass into ashes and slag as a result of combustion

  in energy units with a focus. We thus see an increase

  the mass of waste from thermal power plants

  in the form of ash and slag.

  The waste goes to the slag when it dries and settles little by little. In this state, the waste in question finds only very limited outlets. It is used

  most often for spatial planning, the leveling of

  the ground, flattening the soil for

  land, for the construction of roads and

  housing. More rarely, the mixture of ash and lai

  Tier finds applications as a raw material in the manufacture of building materials: cements,

  binding and filling materials for concretes,

and chippings.

  A high level of iron oxides, reaching 22% in

  weight, opposes the large-scale use of

  ash and slag. The strength of gravel and artificial gravel obtained from ash and slag mixtures is lower than that of similar natural materials and depends on the content of iron compounds. the

  concrete products, obtained with the use of binders con-

  holding ash mixture treatment products and

  slag, have a mediocre presentation that is becoming

  rant. In a humid environment, we can see, on the surface,

  facing works, rust stains.

  The use of ash-slag mixtures in agriculture as a trace element fertilizer is limited by the presence of heavy metals (lead, zinc and others), harmful elements that may pass

in food.

  Another use of ash and slag

  to extract drops of a metal alloy

  (ferrosilicon) containing about 12 to 25% by weight of silicone

  cium. The need for low-silicon silicon ferrosilicon is increasing worldwide, which can be explained by

  the growth of the foundry from reused waste

  and the great extension in metallurgy of refining

oxygen converter.

  Ferrosilicon is a deoxidizer of choice in

  the development of ferrous metals in the iron and steel industry and

  formation of shaped products in foundries.

  In currently known fired energy units, the manufacture of ferrosilicon is not expected, parallel to the production of electrical energy. Although certain conditions are met for this purpose in the

  known units, they are not fully exploited.

  We know a process for obtaining ferrosilicon

  in well-type furnace units: high furnaces

  Narcotics (R. Durrer, G. Folkert "Metallurgia ferrosplavov" ("Metallurgy of Ferroalloys"), Metallurgia, Moscow, 1976. The blast furnace enclosure, coated with refractory materials, is composed of three cylindrical portions and

  two frustoconical portions. the upper cylindrical portion

  the upper part is used for charging the load.

  It adjoins a frustoconical portion occupying most of the

  part of the oven enclosure; it is its tank which contains the essential part of the load descending towards the zones

  at higher temperatures. The base of the truncated portion

  conical is extended by a medial cylindrical portion -

  the belly - which ensures a gradual passage of the load in the second frustoconical portion with inverse conicity: the display. It is supported on the cylindrical part

  lower, which divides, in height, into two zones, the

  and the crucible, the latter ending in a coated bottom, the sole. The crucible collects liquid products

  fusion: the slag above, ferrosilicon

  below. In the upper part of the crucible is provided a taphole for the slag, and in its lower part, a taphole for ferrosilicon. On the perimeter of the structure are arranged nozzles with burners leading into

  furnace, a gas, a pulverized fuel or

  quide. Ferrosilicon is obtained in a well furnace by melting high silica minerals with iron

  or its oxides in the presence of a carbon reductant.

  The process involves the charging by the hopper of the top of a load consisting of quartz, quartzite or other minerals at the rate of silicon dioxide (silica) of not less than 96%, iron chips without rust and a

  solid carbon reductant: small coke. After the charge-

  The furnace is heated by bringing an ignited mixture of gas oil, a gas or coal dust mixed with the air into the burners. When the charge is raised to 1350 C, there is, in the presence of the carbon reducer of small coke, a reduction of iron and silicon from their

  oxides, with formation of ferrosilicum. When reducing

  tion, there is a gaseous carbon monoxide release which is

  evacuated from the oven through the throat. The temperature rise

  This enhancement favors the increase of the silicon content in the ferrosilicum. Ferrosilicum and slag are

  forming a bath. The slag floats on the surface of ferrosi-

  Licium. After a sufficient accumulation of the metal, when the level of the slag exceeds the orifice of the upper casting hole, it is pierced and the slag is withdrawn, after which

  the ferrosilium is evacuated through the lower casting hole.

  Then we close the tapholes with clay

  refractory and proceed to a new melting cycle.

  However, this process provides low silicon ferrosilicon from high-grade ores.

silicon dioxide.

  The process provides for an increase in the rate of metal debris in the load up to 45% by weight and a high

  consumption of specially prepared carbon material, the

  coke tit. However, only 30% by weight of the silicon is reduced from the ore with the remainder of the silicon dioxide passing through the slag. The amount of solid waste is increased in the process in question. In addition, the process for the manufacture of ferrosilicon in a

  household is not combined with the production of electricity

than.

  There is known a method for obtaining ferrosilicon in an energy unit with focus (SU, A, 815060). As fuel, in this hearth unit, carbonaceous materials are used whose slag contains 10 to 22% by weight.

weight of iron oxide.

  The energy unit hearth is formed by four vertical walls, and its sole, by two inclined walls consisting of sections which are bundles of tubes cooled with water. On each longitudinal side of the unit

  in its vertical walls, there are openings for

  tures, arranged in pairs, and allowing burners to

  their. the interior surface of the hearth, at the place of

  The burners and below them, as well as all sloping surfaces of the hearth, are coated with refractory materials. The inclination of the sections of the hearth is oriented towards the tapholes. They are intended to evacuate the slag from the hearth unit in mounted tanks

  below these and filled with water: the granulators.

  The latter are equipped with conveyor belts

  granulated slag to the hydraulic exhaust pipe.

  lique, this slag then borrowing a pipe ending in the slag. In the upper part of the fireplace unit,

  there is a tubular steam generator, put in communi-

  with a steam turbine and an electric generator.

  than. Further, on the path of the heated gases,

  heat exchangers, electrical filters and

  and a tube causing aerodynamic depression

in the home unit.

  Most burners in the fireplace unit are

  to bring coal dust with a coeffi-

  oxygen surplus of 1.1 to 1.19. One or two burns

  their walk to diesel and are intended to maintain the flash temperature of the solid fuel. The need to use diesel fuel burners arises when low-grade fuels with low organic content are used.

and volatile hydrocarbons.

  According to the known method, the carbonaceous fuel,

  air mixture, is brought into the home energy unit.

  The temperature inside the hearth being 1500 to 1550 C, the fuel is ignited and burns with a coefficient of oxygen surplus of 1.1 to 1.19, by heating the gases inside the furnace. home. The gases give up their heat to the heating surfaces of the steam generator, in the tubes of which water is transformed into steam. The latter is brought to the turbine. who puts the electric generator

  in rotation, which produces electrical energy.

  In the furnace, during the combustion of the coal dust, the conditions are met to trigger the reduction reaction of the elements from the corresponding oxides (mineral part of the fuel): the iron, the

  silicon, aluminum, calcium, etc. These conditions.

  are: the high temperature of the gaseous medium in the furnace, between 1500 and 1550 ° C., the presence of a solid (carbon) and gaseous reductant (the carbon oxide) and the sufficient time to carry out the reduction reaction

  and the separation of the products of the reaction. Some

  microscopic effects of a reduced metal, iron for the essential

  and ferro-silicon with a low silicon content are formed in the grains of coal: ash and

  slag on the walls and hearth of the hearth.

  However, the residence time of the carbon particles in the gases brought to a high temperature does not ensure the entirety of the reduction of the oxides of iron and silicon and the agglomeration of the drops of the reduced elements in their alloy: a ferrosilicon to

low silicon content.

  The small inclusions of reduced iron and its alloy with silicon, present in the particles of ashes, can not be considered as a product

  merchant with metallurgical vocation.

  Most (80 to 85% by weight) of the burned fuel is removed from the hearth enclosure, in the form of ash particles, together with the gases released during combustion. By gradually cooling in the heat exchangers, the gases pass through the electrical filters and are released to the atmosphere by the chimney. The ash particles are separated from the gases in the electric filters and washed off in the ash and slag exhaust duct. The pulp of ash and slag goes to the slag by pipes. A minor portion of 15 to 20% by weight; incombustible materials contained in the fuel are deposited on the walls and surfaces of the hearth hearth as slag. This slag migrates at a relatively low speed, which is a function of its viscosity at a given temperature, towards the lower part of the hearth enclosure, towards the taphole. During the course of the slag, phenomena similar to those described above take place in its

breast.

  However, the stable thermal conditions, determined by the great heat capacity of the slag and the considerable duration of its stay in these conditions, favor the full development of the reduction reactions of the oxides of iron and silicon, which are more complete in the slag only in the ashes. In the slag, an alloy is formed. namely a low silicon ferrosilicon, which takes the appearance of distinct drops whose diameter reaches 4 to 5 mm. The alloy drops are discharged through the taphole together with the unreduced mass of the oxides and sent to the granulation tank. The granulation of the melt is carried out with rapid cooling, the consequence being the release of part of the ferrosilicon drops. The ferrosilicon granules can thus be separated from the frozen mineral mass of slag. To this end, in the ash and sludge disposal system with water, there is a station where a hydraulic trap is mounted, which captures

ferrosilicon granules.

  By proceeding in this way, we manage to cumulate,

  in the same household unit, the production of electricity

  that and a partial transformation of solid waste

  from the home in marketable products: a ferro-

  silicon with low silicon content and raw materials

  for the manufacture of building materials.

  Since the reduction leading to obtaining a ferroalloy from the metal oxides takes place at a temperature not exceeding 1400 to 1450 C, which ensures the evacuation of the liquid slag, the latter flowing by gravity on the walls and hearth hearth to the taphole, the viscosity of the slag remains quite high: about 6 to 20 Pa.s. Under these conditions, the exchange of mass within the molten slag is hindered. Drops likely to be collected in hydraulic traps result from the fusion of the ferrosilicon particles constituting 2.5 to 20% by weight

  iron oxides or 0.5 to 2.0% by weight of the slag.

  The method in question provides for obtaining ferrosilicon only from the solid waste portion of the fuel that passes into the slag. This is equivalent to 15 to 20% by weight of incombustible constituents

  solid fuel or 4.5 to 6.0% by weight of the coal.

  Ashes from thermal power plants and slags resulting from the combustion of gas oil are not involved in the described processes for obtaining ferrosilicon and

  of raw materials of construction.

  The object of the invention is to develop a

  process for obtaining ferrosilicon in an energy unit

  house tick, a process which would, by creating the most favorable thermodynamic conditions for the course of the reduction reaction and regulating the thermal regime in the home energy unit, increase the yield of ferrosilicon while providing a technique of electric power generation with a low

amount of waste.

  The problem thus posed is solved with a process for obtaining ferrosilicon in a furnace energy unit using, as fuel, carbonaceous materials

  whose slags contain iron oxides

  portion of 10 to 22% by weight, process of isolating the ferrosilicon from the slag resulting from the combustion process according to the invention, is created in the unit hearth, a slag bath and is brought, on its surface, a jet of hydrocarbon fuel, by heating this bath to a temperature of 1700 to 1800 C, the hydrocarbon fuel being fed simultaneously with products

  pulverized resulting from the combustion of carbonaceous materials.

  The supply of a jet of hydrocarbon fuel ensures the isothermal conditions of the course of the reaction

  reduction. For this purpose, the hydro-fuel jet

  carbon dioxide is brought to the surface of the slag bath

  created in the part of the home adjoining the

  sole and this bath is brought to a temperature of 1700 to 1800 C.

  The creation of the slag bath ensures favorable conditions for overheating of the molten slag from 200 to 250 ° C. with respect to the normal temperature of liquid slag evacuation. This is made possible by the additional heat generated during the burning of the hydrocarbon fuel. In addition, the existence of a slag bath creates favorable thermodynamic conditions for the reduction of iron oxides by carbon, namely the constant and higher temperature of the medium which is the molten slag containing the metal oxides. and the carbon reductant provides a larger reaction area of the reduction. As a result, the reduction reaction may take up a greater part of the iron oxides and other metals than

in the known process.

  On the other hand, a low viscosity of the medium in which the reduction reaction takes place favors a more intense mass exchange. The gaseous products of the re-action are released and rise to the surface of the molten slag in a more intense way. The drops of molten metal, resulting from the reduction from its oxides, descend by gravity and accumulate on the bottom of the hearth. Because of the great difference between the densities of the slag and the metal, the latter forms, on the bottom of the hearth, a layer of alloy of Si and Fe. This is what allows to organize the technological process so as to ensure the proper casting of slag and metal alloy,

especially ferrosilicon.

  The supply of pulverized carbonaceous materials simultaneously

  with the hydrocarbon fuel promotes the entry, in reduction, of the most easily reducing oxides.

  increasing the yield of ferroalloys.

  It is advantageous to use, as pulverized carbonaceous materials, the products resulting from the combustion of the carbonaceous materials, these products originating in

  the home energy unit itself.

  This helps to reduce waste-production

of electrical energy.

  The proposed process for obtaining ferrosilicon in

  an energy unit with a focus makes it possible to obtain, simul-

  at the same time and in the same group, thermal energy or

electric and ferrosilicon.

  The rational combination of the two processes provides an unprecedented product for energy units. Its production uses energy committed to melt the part

  incombustible coal, turning it into a slag.

  The realization of the combined process requires only one

  low amount of extra heat. It is necessary

  to overheat the slag from 200 to 250 C in order to improve the mass exchange during the metal reduction reaction from the oxides contained in the slag.

  The introduction into the jet of hydro-

  the additives mentioned above makes it possible, on the one hand, to improve the yield of ferrosilicon, and on the other hand

  to further reduce solid waste.

  As a result of the above, the proposed process allows the generation of thermal or electrical energy using the heat of the molten slag and partly the solid waste of the fuel with a small amount of waste. energy in thermal power plants for the production of ferroalloys and raw materials for the manufacture of building materials. The best non-limiting embodiment variant

  of the invention consists of the following.

  The process of the invention is carried out in any known hearth energy unit, which uses, as fuel, carbonaceous materials whose slag contains iron oxides in the proportion of 10 to 22% by weight. This is how the fireplace unit can be formed by four walls

  vertical, and its bottom, by two inclined walls constituting

  killed sections that are bundles of tubes cooled with water. These sections are lined internally with refractory materials. In the front wall and the rear wall of the hearth unit, there are openings in which burners are arranged arranged in pairs, facing each other. The stove energy unit normally has eight to twelve burners, one or two of which burn with hydrocarbon fuel, preferably with gas oil or natural gas, and the others with solid carbonaceous fuel.

  pulverized: coal, peat, schist.

  In the unit under consideration, the burners operating at

  hydrocarbon fuel are oriented towards the bottom of the

  té à foyer. In addition, they are provided with a system for feeding pulverized materials together with the fuel

hydrocarbon.

  In the sole part of the energy unit

  yer, there are provided tapholes for the slag. Linen-

  tilting of the sections forming the hearth of the hearth unit

  is directed towards these tapholes, serving for the evacuation

  slag. Around the tapping holes is provided a protection in a refractory material. This protection, with part of the sections of the hearth, forms the enclosure filled with molten slag during the operation of

  the energy unit with focus, forming the slag bath.

  In the sole is a taphole for the evacuation

  ferrosilicon. Immediately below the holes of

  casting for the slag are arranged granular tanks

  equipped with conveyor belts for the conveyance of

  pellet cooled to the central exhaust duct

  dres and slag with water. This conduit is put in

  communication with a pumping station, the pumps of which are connected to the pipe leading to the crassier of the

thermal power station.

  The regulation of the combustion regime in the energy unit with focus is made by changing the flow of the

  fuel supplied by the burners, and that of fuel

  the ratio of which is defined by the coefficient of

  oxygen tooth. It normally has a value close to unity. When burning carbon fuel, there is a release of heat that heats the surface of the water-cooled tubes. There is formation in the tubes of a superheated steam. It is fitted to a turbine that puts a

  rotor of a generator of electrical energy in rotation.

  Combustion not only provides heat,

  but also generates solid particles of

  unburned fuel, ashes carried away with hot gases, and slag. These materials are waste

  the production of electrical energy.

  The slag deposited on the walls of the hearth trickles over them to form a slag bath in the hearth part of the energy unit. The temperature of the slag is close to that required for evacuation

  normal liquid slag of a given fuel.

  Directing, on the surface of the slag bath, the torch of a burner moving to a hydrocarbon fuel,

  diesel, whose calorific value is higher than

  with that of the pulverized carbon fuel (coal,

  peat, shale), the slag bath is brought to a temperature of

from 1700 to 1800 C.

  Heating the slag bath to the temperature

  from 1700 to 1800 C increases the yield of iron and

reduced.

  These data were obtained experimentally

and are summarized in Table 1.

TABLE 1

  N Temperature Silicon ferro- rate reduced silicon slag in molten ferro-aluminum, C% of the weight of the slag silicon

1 1,550 0.6 8 to 12

2 1 610 '1.85 10 to 14 traces

3 1,650 2.4 10 to 17 0.56

4 1,700 6.8 18 to 25 0.67

1,720 7.4 22 to 28 1.11

6 1,760 8.3 24 to 32 1.86

7 1 800 10.1 34 to 40 1.96

8 1,810 6.1 17 to 22 4.7

9 1,840 3.7 14 to 17 9.63 -

  It can be seen from Table 1 that the optimum result is obtained with a warming of the slag bath at a

  temperature included in 1700 and 1800 C.

  It is not advantageous to heat the slag bath to a temperature below 1700 C, because the reduced ferrosilicon yield is maintained at the level of the process

known described above.-

  The heating of the slag bath at a temperature above 1800 0C can not be recommended, as we observe

  a fall in the yield of ferro-silicon due to the

  of the mono-silicon oxide. At the same time, there is an increase in the amount of aluminum reduced,

  from its oxide. Its presence in the pre-alloys

  xydants is undesirable and regulated by specifications

  corresponding metallurgy. In addition, at temperatures

  such a high material, the material forming the coating of

  slag bath undergoes intense destruction.

  The process of reducing iron and silicon from their oxides at a temperature of 1780 to 1800 ° C should be regarded as optimal, ensuring a ferroalloy yield of up to 10% by weight

  and a maximum silicon content in the alloy, up to

than 34 to 40% by weight.

  At a temperature of 1700 to 1800 C, the viscosity

  slag, which is at the origin of 4 to 6 Pa's, is seen

  up to 1 to 2 Pa.-s. In a medium with a low hydraulic resistance, the intensity of the mass exchange increases on the surface of the particles of the solid deoxidizer (coal) thanks to the transport of the drops of iron and silicon reduced towards the bottom. of slag bath and carbon monoxide bubbles rising to the surface of the

  slag bath. Then, the gases that emerge on the surface

  face of the slag are entrained with the gases released during

*combustion.

  On the other hand, with a low viscosity of the slag, under the effect of the force of gravity, a demixing of the molten slag occurs. In the lower part a layer of reduced metal accumulates, and above

  from her, that of slag, lighter. Throughout

  energy unit, the transport of metals downwards and the rise of slag

  Heavy metals continue unabated.

  Elevation of the temperature of the slag bath

  up to 1700 to 1800 C has the effect of increasing the

  reduced metal from the slag and to improve its quality through thermodynamic conditions more

  favorable course of the reduction reaction.

  Simultaneously with the hydrocarbon fuel,

  brings to the surface of the slag bath, pulverulent products

  values resulting from the combustion of carbonaceous materials and

  arising in the energy unit at home

even.

  The supply, together with the hydro-

  carbon, pulverized products resulting from the combustion of carbonaceous materials, in particular coal dust and ash, on the surface of the slag bath, increases the amount of solid waste from thermal power plants that

  can be reused, and hence the amount of ferrosilicon

  obtained and raw materials for the manufacture of

  building materials, cleared of iron oxides.

  As pulverized products resulting from the combination

  burning of carbonaceous materials, not only can

  products from the energy unit itself, but all other products sprayed

  from the combustion of carbonaceous materials.

  The feeding of the pulverized products resulting from the combustion of carbonaceous materials on the surface of the slag bath by a simple spill would lower the temperature of the upper layer of the slag, by making a screen effect

  on the heat transfer to the slag by radiation.

  To avoid this, the introduction of the resulting pulverized products

  so much of the burning of carbonaceous material is carried out

  in the hydrocarbon fuel jet. High temperature

  the torch warms the sprayed additive, which

  to keep track of the contribution of heat to the

surface of the slag bath.

  As and when the ferroalloy builds up,

  the thickness of its layer in the slag bath increases.

  The ferroalloy is periodically poured through the lower casting hole, the periodicity being a function of the volume

  slag bath. and the type of home energy unit.

  Then, the taphole is plugged leaving a small layer of ferro-alloy that accumulates until the casting

  next. The upper layer of slag moves in con-

  tinu walls to the taphole. It passes the protection

  and enters the granulation tank, then goes into a hydraulic trap and into a hopper for

first of construction.

  Other features and advantages of the invention

  will be better understood by reading the description that will

  follow several nonlimiting examples of realization

  of the process for obtaining ferro-silicon in an energy unit

Geothermal.

Example 1

  49.2% by weight of silicon oxides, 25.4% by weight of oxides, are blown into a furnace energy unit, mixed with air, of which the slag contains 49.2% by weight of silicon oxides.

  of aluminum and 15.4% by weight of iron oxides, the coeffi-

  excess air is 1.1 to 1.19. The mixture is burnt at a temperature of 1500 to 1550 C. Part of the incombustible materials of coal, containing 20% by weight of ash, is deposited on the walls of the hearth, below

  from the level of the burners, then down on the hearth of the hearth.

  The slag accumulates there to form a slag bath. On the surface of the molten slag, a jet of gas oil is taken, raising the temperature of the slag to 1650 C. After

  have accumulated ferrosilicon for 16 hours, it is

cue through the taphole.

  The amount of ferrosilicon is 2.4% by weight

  compared to the slag. The silicon content in the alloy goes

  between 10 and 17% by weight. The aluminum content is lower

0.6% by weight.

Example 2

  The same coal is burned under the conditions of

  Example 1 by bringing a jet of gas into the surface of the slag bath.

  when the temperature of the slag bath is raised to 1700 C, the

  heating is 100 to 150 C with respect to the normal exhaust temperature

male slag in the liquid state.

  Ferrosilicon is finally obtained with a silicon content of 18 to 25% by weight, whereas the yield of ferrosilicon is

  6.8%, by weight, better than that of Example 1.

Example 3

  the same coal is burned, under the conditions of Example 1, by raising the temperature of the slag bath

up to 18000C.

  The yield of ferrosilicon is 10.1% by weight, the level of silicum in the alloy being 34 to

  400 by weight, that of aluminum, of 1.96% by weight.

Example 4

  By burning the same coal and raising the temperature

  of the slag bath until 1840 C, we have seen the

  ferrosilicon drop to 3.7% by weight. The silicon content in the alloy was 14 to 17% by weight. The reduced aluminum content has however increased to 9.6% by weight.

Example 5

  Coal containing 56.4% by weight of silicon oxides, 22.5% by weight of aluminum oxides and 11.0% by weight of oxides is burned in a furnace energy unit. of iron. The pulverized fuel is brought

  in the combustion chamber with the air, the coefficient of

  oxygen tooth being 1.1 to 1.19. After the formation, on the sole, of a slag bath, a burner is placed facing the surface of the slag bath in operation. The jet emitted by this burner, containing a mixture of air, gas oil and pulverized products resulting from the burning of the fuel,

  maintains the temperature of the slag at 1700 C.

  In this jet, the proportion of the pulverized products resulting from the burning of the fuel is 0.1% by weight relative to the slag resulting from the burning of the coal in question in

  the home energy unit itself.

  The reduced ferrosilicon yield is 10% by weight, the silicon content in the alloy is about 30% by weight, that of aluminum is less than 1% by weight.

  the examples cited show that temperatures

  temperatures between 1700 and 1800 C are optimal for the slag bath. At these temperatures, the maximum yield of ferrosilicon is obtained for a maximum level of aluminum oxides.

Claims (2)

R E V E N D I C A T I 0 N S   A method for obtaining ferrosilicon in a furnace energy unit, using as fuel carbonaceous materials whose slags contain iron oxides in a proportion of 10 to 22% by weight, consisting in isolating the ferrosilicon from the slag resulting from the combustion, characterized in that a slag bath is created in the fire energy unit and a   jet of hydrocarbon fuel, warming up this bath until   at a temperature of 1700 to 1800 C, bringing simultaneously   with the hydrocarbon fuel, pulley products   risings resulting from the combustion of carbonaceous maitères.   2. Process for obtaining ferrosilicon in a   an energy unit with a combustion chamber according to claim 1,   because, as pulverized products, the products of combustion of carbonaceous materials   birth in the home energy unit itself.