DD250551A5 - METHOD FOR PRODUCING METALLURGICAL COMPOUNDS - Google Patents

Abstract

The invention relates to a process for the production of metallurgical composites for use in iron smelting processes. The aim of the invention is the provision of novel composites which have a high strength. The process according to the invention comprises the following steps: (a) action of shearing forces on lignite to produce a plastic mass; (b) mixing finely divided ore and / or concentrate with the coal either during or after step (a); (c) compressing the mixture produced in step (b) to produce a compacted mass; (d) drying the compacted mass to produce the metallurgical composite. Step (c) is preferably carried out by extrusion. The invention also relates to a melting process in which the composite is heated to a temperature at which the ore or concentrate is reduced to metal.

Description

Field of application of the invention

The invention relates to a process for the production of metallurgical composites and to processes using these composites.

An aspect of the invention relates to composites of metallic oxide ores and treated lignite, peat or biomass, and to processes for their production.

Another aspect of the present invention relates to a wide range of botanicals which are phytochemicals, including mosses, generally non-woody, at various stages of bacterial conversion, and methods of treating them.

Methods of treating the composites to engineer the metal oxides therein, including fusing, are also provided by the invention.

Characteristic of the known technical solutions

The upgraded lignite used in the invention is preferably a product of the invention described in co-independent Australian Patent Application 24294/84, published on August 23, 1984 and / or 52590/86 (PG 9283).

The lignite beneficiation / densification process described in the aforementioned co-pending patent applications is a process whereby soft lignite with a degraded water content of about 60% is converted to a hard, abrasion-resistant black solid having a water content of about 10%.

In the process, the lignite with the water content of the degradation state is subjected to shear / attrition in a selected kneading apparatus for a period of time ranging from five minutes or less to one hour or more depending on the hardness required in the finished compacted product.

The shear performs various functions that are important in the context of the invention. The coal is converted into a fine particle form whereby at least part of the water content originally dispersed in the porous structure of the coal is converted into a loose water phase, by which the coal becomes moist and plastic, and finally a very large number and very many regions freshly split coal surfaces are produced. These freshly cleaved surfaces are involved in inter-particle bridging processes which eventually cause the carbon mass to harden and become much denser, with the simultaneous exclusion and loss of most of the original water. Density increases of about 0.8 to 1.4 are not uncommon. The loss of water is fast (for example, 80% in 24 hours in calm air at 20 ° C), and the maximum hardness is achieved within three to four days. After grinding, the now plastic coal is subjected to considerable pressure by suitable extruder or high pressure briquetting equipment, e.g. a ring roller press, compacted. In a particular example, the compacting plant is in the form of a screw-driven piston-body machine which produces cylindrical test specimens of either 3 to 10 mm in diameter, which can be cut to any length. It is believed that the application of pressure during extrusion is important in order to force the freshly split surfaces of the carbon particles into close proximity, thereby facilitating bridge bonding and greatly improving the rate at which bonding occurs. By using higher pressures during extrusion, coal recovery times can be greatly reduced. Times of only five minutes or less become possible, especially if a powerful attrition machine is used.

The least amount of time required for shear trituration of crude lignite in the compaction process is that sufficient to produce perceptible moisture and plasticity in the bulk of the coal. In practice, the required condition is determined by experiential visual assessment. The length of time is a function of the speed of operation of the attrition machine, the intensity of the shearing action achieved by the machine, and the ability of the machine to consistently push the coal into the shear zone.

With regard to very short shearing times, the water content of the coal can be critical; if it is too low, the machine performance drops considerably. Experience has shown that lignites with water contents of about 60% by mass have optimum shear-attrition properties, whereas water contents close to 54% (or below) are unsatisfactory.

Using a sigma kneading machine running at a kneading shaft speed of 40 and 20 rpm and a rotor wall distance of 0.3 mm, various lignites from Victoria and Germany were successfully converted into extrudable plastic with shear frictional times of 30 seconds , However, 30 seconds should not be considered the minimum time according to the claim of the invention because time is determined to a considerable degree by the performance of the available machine. Any time sufficient to convert the lignite coal into an extrudable plastic state will be adequate. It should be noted that, in practice, short shear attrition times leading to limited size reductions of the carbon particles can be compensated to some extent by the subsequent application of high extrusion pressures. In fact, a relatively dry plastic mass leads to the development of high pressures in the nozzle area of an extruder.

Another preferred embodiment of the invention relates to a continuous shear strand process. The very short attrition times enable a continuous operation in which the lignite is continuously fed into small lumps (5 mm or less) in a slow-speed (20 to 40 revolutions per minute) sigma-type shear-grinder. The construction of the machine is designed so that a residence time of the coal in the shear zone in the required order of magnitude (as defined above) is achieved before it is squeezed out by means of a correspondingly arranged discharge screw. The discharge screw feeds the wet, crushed coal to an extruder head which is designed to produce the required extrusion pressure and pellets which are sufficiently strong so that they can withstand adequate loads immediately after formation.

A machine performing the functions described above and having a discharge screw and an extruder as integrated parts is a Sigma kneading machine HKS 50.

While there are no limits to the beneficial effects observed by any hypothetical or hypothetical mechanism, it is believed that compaction will begin at an acceptable rate once sufficient split sheared coal surfaces are available. This provides a further improvement which results in a continuous process in which the coal has a residence time in the rubbing (shear) zone which is just sufficient to produce a material which will successfully extrude in a high pressure extrusion or pressing line can be.

Investigations of the properties of dried compacted lignite pellets prepared in this manner have shown that they maintain their shape and often become much harder when progressively heated to higher temperatures. At temperatures between 300 and 400 ⁰ C volatiles develop in the form of water vapor and low molecular weight organic substances (mainly phenols). Above about 500 ^° C only permanent gases (mainly hydrogen, carbon monoxide, carbon dioxide and methane) are produced. The investigation of compacted lignite has its potential utility for certain metallurgical applications, e.g. B. composite pellets result.

Object of the invention

The aim of the invention is the provision of novel metallurgical composites which can be advantageously used in iron smelting processes.

Explanation of the essence of the invention

The invention has for its object to produce novel lignite briquettes oder.-pellets, peat or biomass with a content of ore and / or concentrate, which have a high strength and are particularly suitable for metallurgical processes.

According to the invention there is provided a process for the production of metallurgical composites characterized by the following steps:

(a) action of shear forces on lignite, peat or biomass to produce a plastic mass;

(b) mixing finely divided ore and / or concentrate with the coal, peat or biomass, either during or after step (a);

(c) compacting the mixture produced in step (b) to produce a compacted mass;

(d) drying the compacted mass to produce the metallurgical composite.

The densification step (c) is carried out according to the invention by extruding the mixture. The drying step (d) becomes. at or after ambient temperature.

According to the invention, the ore which according to the invention is added to the brown coal mass, peat or biomass is iron ore or chromite ore. As an ore or concentrate but can also be added a zinc ore or concentrate. The plant material is processed according to the invention before incorporation into a composite to a denser and stronger product. The product has a higher calorific value than the starting material and can be used as fuel and also for the metallurgical treatment of ores and concentrates, being a particularly effective binder and reducing agent, and this aspect is of particular interest to the invention.

Naturally occurring peat species are products of anaerobic bacterial conversion in humid environments. An aspect of the invention provides a first step of subjecting suitable plant material to anaerobic bacterial conversion to conditions which simulate the peat formation required. This step produces a bacterially altered, soft plant material that has similar properties to naturally occurring peat species.

The treatment step of the invention can be applied to naturally occurring peat species as well as to the above-mentioned bacterially altered soft plant material.

Generally, anaerobic conversion occurs when green or wet plant material is isolated in a mass from the atmosphere and maintained in that state until the anaerobic bacteria have consumed the readily available saccharides. The resulting material is coherent, has a dark appearance, its pulp is greatly reduced and it has relatively uniform properties. It will consist of unaffected cellulose, lignins and tannins together with a significant amount of extracellular polysaccharides produced by the anaerobic bacteria. These polysaccharides serve as binders and produce cohesion in the converted mass. Any softer wet plant material (leaves, stems, twigs, fruits, but excluding solid wood constituents with a high lignin or cellulose content) is suitable for anaerobic bacterial conversion.

The bacterially altered soft plant material is comparatively stable on exposure to air, presumably due to the fact that it consists of the remaining solid plant constituents cellulose, tannins and lignins together with large proportions of bacterial extracellular polysaccharides, which are high molecular weight polymers with adhesive Properties trades.

In accordance with the present invention, natural peat or transformed plant material is treated by being subjected to shear forces, in other words, it is ground in a mixing or kneading machine, conical pulp mill or other suitable machine, for example a sigma mixer, rather than crushed or otherwise treated becomes. Under appropriately controlled conditions, it is readily converted to a dark colored, wet, plastic mass from which pellets, briquettes or other required shapes are then formed by briquetting extrusions or other densification measures.

The molded bars, pellets or other shapes are allowed to air dry for several days (or, if desired, are dried faster in respective ovens), with gradual hardening to produce hard, tough, somewhat vitreous solids. The shrinkage due to water loss is considerable. The peculiarity of the bonding process, whereby the crushed material takes on a hard, coherent and dense texture, can not be explained with certainty. Nevertheless, it is believed that the highly reactive polyhydroxyphenols (derived from the tannins in the plant material), along with the bacterial polysaccharides, are involved in the formation of a crosslinked polymer matrix.

Bacterial polysaccharides, e.g. As the well-known xanthan gum, are notable for their adhesive properties.

When heating the recycled material, gas production in the processed material of the present invention appears to be somewhat stronger compared to naturally occurring peat, and there is a corresponding decrease in the mass of solid residues. Gas evolution occurs rapidly over about 370 ⁰ C and is very fast over about 430 ° C. It continues for a while after reaching 600 ^° C., and if this temperature is maintained for a few minutes, gas and liquid can be collected. ·

While there are no limits to any of the assumed or theoretical mechanisms regarding the observed beneficial effects of the invention, the following considerations are certainly important:

(a) Trituration of the raw coal to produce the above-mentioned wet or wet plastic mass is a suitable measure for the effective incorporation of finely divided particulates such as crushed metal ore or concentrates,

(b) the fine distribution state of the crushed coal is required for a very close physical union of particles of metal ore and particles of plasticized coal, the latter acting as a strong reducing agent,

(c) spontaneous evaporating water loss occurs from the pellets during the compression reaction to form hardened, dry pellets, which are particularly suitable for relatively rapid heating for metallurgical purposes.

(d) when heated above about 500 ° C, the compressed lignite develops considerable quantities of a gas mixture having a strong reducing character,

(e) after pyrolysis or cryogenic carbonization, the pellets provide a residual carbon which has a highly reactive form which is very closely associated with the phases to be reduced. In this context, it should be noted that lignite cokes are known to be effective and fast metallurgical reductants. In addition, reactive carbon in the compressed lignite increases hydrogen, and prior to this, the existing nascent form of hydrogen greatly enhances the reduction reactions.

Extensive experimental investigations have shown that finely divided ores and concentrates, especially oxidic iron ores, readily mix with wet plasticized coal, peat or biomass, and that upon addition of the latter during trituration, a smooth homogeneous mixture results. Such a mixture is easy to extrude or briquet, and the pellets or briquettes thus produced dry and harden to a surprising extent. In some cases, the cured product exhibited a fairly reduced air-drying strength but is often recovered by pyrolysis. In other cases, an obvious reaction between the inorganic phase and the carbon components takes place, resulting in significant increases in the strength of the dried product.

The metallurgical behavior of various composites is described in the examples given later. Research has shown that very high rates of reduction can be achieved in lignite composite pellets. As stated, it may be possible that a significant contribution to the reducing power of the system is made by the newly developed atomic or nascent hydrogen produced during the preliminary heating of the composites. Polyhydroxyphenols are believed to contribute the majority of pyrolytic hydrogen, but other reactive species may be involved. The evolution of atomic hydrogen in close proximity to the phase to be reduced provides the opportunity for extremely rapid and efficient reduction of the solid ore particles.

Plant material ore / concentrate composites have also been studied and found some valuable benefits:

(a) a natural ability that allows the incorporation of a fine ore or concentrate into a plastic matrix, which then hardens and loses water through evaporation, creating a composite that is well-suited for subsequent pyrometallurgical operations.

(b) Inferior ores may be incorporated into the composites with little or no pretreatment. Gangue components contribute to slag formation. Other slag-producing ingredients, for example lime, can readily be incorporated into the composites.

(c) A very close association of the ore granules with the carbonaceous matrix is developed which acts as a reductant during subsequent pyrometallurgical operations.

(d) The thermal decomposition of the carbonaceous matrix yields reducing gases, such as carbon monoxide and hydrogen, in the immediate vicinity of the ore or concentrate granules.

(e) The high reactivity of the treated material or the resulting semi-coke facilitates the Bouduard reaction CO2 + S2CO, which maintains a high partial pressure of carbon monoxide.

In summary, composite materials according to the invention offer considerable advantages because they contribute to their ability to:

(a) effective bonding - in the cold state - of finely divided ores or concentrates,

(b) sufficient strength in the green composite pellets or briquettes, peat or biomass to allow satisfactory handling during drying and subsequent use in preheat or "pyrolysis" furnaces.

(C) faster and more effective reduction of oxide oxides, especially iron oxide ores, but also by others, such as. B. Chromite ores.

(d) an ideal opportunity for the simultaneous transport of partially or even substantially metallized pellets or briquettes together with carbon to smelting furnaces, especially those using state-of-the-art smelting technologies.

(e) reduced metallized pellets or briquettes which can be easily handled, transported and stored without the risk of reoxidation or the occurrence of pyrophoric behavior as is the case with various types of pre-reduced iron ore composites now available.

Useful composites containing certain non-noble metal ores and concentrates, e.g. As zinc concentrates can also be produced.

embodiment

The invention is explained in more detail below with reference to some examples.

example 1

In this preliminary test, compacted lignite-iron ore composite pellets were prepared as described below and then heated to determine the type and amount of evolved gases.

Dried compacted lignite-iron ore composite pellets containing 75% iron oxide were prepared using the procedure described in Example 2. It was used Loy Yang coal from the deposits of Latrobe Valley in Victoria, Australia. After a pre-pyrolysis in a nitrogen atmosphere at 400 ⁰ C to remove water and low molecular weight organic volatiles, the pellets were placed in a attached to a vacuum system silicon dioxide tube.

After all the air was removed by pre-pumping, the temperature of the pellets was progressively increased up to 900 ° C. Samples of gases evolved at three different temperatures were taken for analysis on a mass spectrometer. The main gases were hydrogen, carbon monoxide, carbon dioxide, methane and a small amount of water vapor. The approximate relative partial pressures of the first four products at the three temperatures are shown in FIG.

Hydrogen was the most abundant constituent at 600 ⁰ C, followed by carbon monoxide and carbon dioxide (approximately equal) and the least abundant methane. When the temperature was raised to 900 ^° C., the evolution of hydrogen outweighed that of carbon monoxide, while that of carbon monoxide also increased. Carbon dioxide fell considerably and methane decreased to a lesser extent.

From this experiment, it is clear that the densified pellets generate a strongly reducing atmosphere when heated to high temperatures. This atmosphere exerts a strong reducing effect in addition to any direct reduction by a solid reactive carbon or nascent hydrogen within the composite pellets or briquettes

Example 2

Composite pellets were made with various proportions of fine iron oxide and coal from Morwell, Victoria, Australia (N3372 well).

In either case, 200g of raw coal (60% water) was run for 4 hours in a Sigma Kneading Machine as described in co-pending application Aust. Kneaded 24294/84. Fifteen minutes before the kneading was completed, selected amounts of fine iron oxide (laboratory reagent material) were added to the plastic mass, and kneading was continued until a thoroughly blended, smooth plastic mass was formed. This was then extruded by means of a hand-operated screw extruder to produce cylindrical pellets having an initial diameter of 10 mm (about 8 mm after drying) and a length varying between 10 and 20 mm. The pellets were allowed to dry for 7 days in quiet laboratory air at 20 ^° C. and allowed to harden. The dried pellets were next subjected to pyrolysis in a stream of nitrogen gas, initially held in the temperature range of 300 to 400 ^° C for one hour to eliminate residual water and low molecular weight organic volatiles, followed by further heating for one hour with an increase in Temperature at 700 ⁰ C followed. In this final period of heating, it should be determined if a detectable reduction had occurred in the temperature range in question. In one case (see below) pellets were heated at 1070 ⁰ C, on this occasion in the coal pyrolysis generated by the reducing atmosphere.

Pellets of 10, 30, 50 and 75 mass% (in dry weight of coal) iron oxide were produced. The 10% composites had an average breaking strength of 17 MPa over 30MPa for comparable pellets containing no iron oxide; After pyrolysis, the 10% iron oxide pellets showed an increase up to an average breaking strength of 20 MPa, indicating the development of further bonding during pyrolysis. The compression / fracture strengths of the dried compacted carbon pellets were determined after measuring the height (H) and the diameter (D) of the pellets to be tested with a micrometer.

The pellets were then placed on the anvil of a universal testing machine (Tirius Olsen Testing Machine Co., Willor Grove, Pa.) And an axial load was applied to the flat ends until breakage occurred.

The compressive strength a _c was calculated from the force F (determined from the maximum load that can withstand the pellet) according to the following formula:

O = ₀ (4F / TTD ²⁾ (H / D) ⁰ · ⁵

All composites were highly magnetic after pyrolysis up to 700 ⁰ C (especially the mixture of 75:25 ore: compacted coal), indicating the formation of reduced iron.

, In one experiment, pellets containing 75% Fe ₂ O ₃ were placed in a silica tube attached to a vacuum system. From the tube, all the gases were pumped out, wherein it was heated to 500 ⁰ C. The tube was then removed from the pumps, and the pressure change was observed with a further increase in temperature at an approximately constant speed to 1 070 ⁰ C. The results of these measurements are contained in FIG. At about 900 ⁰ C began a very rapid pressure increase, and it had to be pumped off gas to keep the total pressure below one atmosphere. Significant gas evolution continued until the end of the experiment. The phenomena described in this experiment are typical of pellets containing iron oxide and indicate chemical reactions between the oxide and the coal-derived species.

At 800 ^° C., the main reaction appears to be the reduction of iron oxide by hydrogen evolved to produce water. This reaction seems to be promoted at about 900 ⁰ C by reduction reactions involving carbon monoxide and carbon, with a real significant increase in the total gas pressure is recorded. Upon completion of this experiment, although the pellets are highly ferro-magnetic, they did not show any visible metallic iron. When the temperature was further increased and pellets were used as electrodes in a DC arc in an inert atmosphere, spheres of pressure-deformable iron were very rapidly generated.

Composite pellets containing 75% Fe ₂ O ₃ for a prepyrolysis to 700 ⁰ C, as described above, were further tested by immersion in a bath maintained at 1500 ⁰ C bath of liquid iron. Gas evolution started immediately upon immersion and continued for 30 seconds during the immersion period. The pellets did not disintegrate, but continued to evolve gas as they rapidly dissolved in the liquid iron. The dissolution rate was highest at the side of the pellet which had been exposed to the highest temperature by contact with the furnace wall during the pre-pyrolysis; probably was in

This zone of the pellet more reduced iron so that the rate of attack was increased by the liquid iron. This experiment shows that the composite iron pellets in a pre-reduced state can be used as feedstock for the supply of iron and carbon in steel smelting furnaces for new bath fusing technology.

It should be emphasized that the invention in its general aspects is not limited to specific details mentioned above.

Example 3

Processed plant material was prepared from hay of oat stalks and used to produce fine iron ore composite pellets. The processed material was made up of a heap of piled up and compacted oat hay, the lower layers of which had become wet three or four times and effectively sealed under some pressure from the remainder of the heap. Over the course of several weeks (with a daily temperature of about 15 ^° C.), the lower layers were converted by anaerobic bacterial decomposition into a dark, coherent and uniform mass, which subsequently remained stable even in the presence of air. Portions of the above material were ground in the hammer mill and then ground in a sigma kneader with a small amount of water just enough to produce a stiff, smooth, plastic mass after a kneading time of about ten minutes. At this stage, the fine iron ore was added and mixed to obtain a uniform material containing about 50% by mass of ore.

After extruding to form O-mm pellets, the product was air dried for several days to give solid, dry, coherent pellets suitable for melting. A preliminary pyrolysis of the composites was done at 800 ^° C. in a closed tube furnace to reduce the loss of volatiles to the minimum dimensions. The swirling composites were hard and coherent and reacted strongly to a magnetic field, indicating a significant reduction in fine iron ore.

Ten of the composite pellets were placed in a clay-graphite crucible and heated from the outside to the dark red-hot with oxygen-acetylene-flame for five minutes, with the oxygen directed at the hot pellets at this stage. The pellets rapidly reached very high temperatures with the burning of the carbon, followed by a partial reoxidation of the initially reduced iron. The final product contained much metallic iron and a fayalite magnetite slag. The siliceous component of the slag came almost exclusively from the iron ore because the processed synthetic peat had a very low ash content (of potassium and magnesium silicates). In another trial, several of these composite pellets were placed in a graphite crucible arranged for atmospheric control. By feeding a stream of nitrogen to the crucible, the temperature was raised to 1 500 ^° C. by induction heating and held at this value for one hour. After cooling in nitrogen, the crucible was found to contain shiny metallic iron in molten globules separated by residual tar, an indication that the reduction had occurred. This experiment demonstrated that the composites are useful as feedstock for bath smelting operations. Carbon enrichment at an initially low temperature (up to 700 ^° C.) would be desirable for the removal of the required level of volatiles.

Example 4

A reported water content of 60% in natural peaty material (from Lake Muir in southern western Australia) was reduced to about 40% by solar drying. The volatiles content was 25% and solid carbon 10.5%.

In a first trial, 200g of this material was triturated for 10 minutes in a Sigma kneading machine from Janke & Kunkel, model HKS50. Water was added to the peat to restore its original content to 60% and a moist plastic mass formed. The plastic material was extruded into cylinders with a diameter of 10 mm with a hand-operated screw extruder. Exposure to a laboratory atmosphere (25 ^° C., 55% relative humidity) over a period of four days resulted in significant water loss and consequent hardening of the extruded cylinders. These became hard, tough and resisted decay during handling and storage.

When heated in air, the dried pellets freely developed a flammable mixture of gases and vapors while the residual solid ignited and slowly burned to produce a small amount of ash. With the supply of oxygen, the combustion was very fast, and high temperatures were reached. The grated wet material proved to be well suited for the incorporation of fine ores. In a second experiment, therefore, 20 mass% of fine hematite iron ore was added to the material at the end of the grinding period in a kneader. After a further kneading time of 3 minutes, the ore had been thoroughly mixed into the wet plastic mass, and the material was extruded as above, and the resulting pellets were dried under the action of air. The resulting composite pellets were hard and firm.

Melting was then performed on the composite by placing a batch of pellets in a small ceramic clay crucible heated from the outside with an oxygen-acetylene flame. After a short time, oxygen was blown through a ceramic tube onto the crucible contents, which quickly became incandescent and burned to a molten residue.

After cooling, examination of the crucible contents revealed that metallic iron had been produced together with a magnetic slag overlying it. The iron (in the form of drops) showed that it had a purity of more than 99.5% metallic Fe.

In a third experiment, finely divided nickel laterite (0.9% nickel, 0.12% cobalt and 0.85% iron) from Ora Banda of Western Australia was incorporated into the same previously used material in the kneading machine. The dried pellets, when melted in the crucible under oxygen blowing, produced numerous small beads of a nickel-iron alloy. The beads were generated very rapidly within 20 to 30 seconds after the start of oxygen blowing. The pyrolyzing and incinerating processed synthetic peat evidently developed a very considerable reducing power within the confines of the composite.

Example 5 -

In this example, a natural peat from Somerset was used in the United Kingdom. This material was comparatively dry on receipt, had a dark brown appearance, and had a significant concentration of plant fibers. When ground as described in Examples 1 and 2 with the addition of some water, the material quickly assumed a wet plastic state. Any slight addition of water during trituration resulted in the immediate formation of individual pellets - evidently an indication of spontaneous binding of triturated fragments. The extruding and drying behavior was very similar to that of the peat from Lake Muir. The result was a tough hard product that showed similar combustion characteristics.

Somerset's material was used to make composite pellets containing calcined zinc sulfide concentrates. Melting the composites in a heated open pot with additional oxygen supply resulted in heavy production of zinc fumes.

Claims (10)

1. A process for the production of metallurgical composites, characterized in that it comprises the following steps: (a) action of shear forces on lignite, peat or biomass to produce a plastic mass; (b) mixing finely divided ore and / or concentrate with the coal, peat or biomass, either during or after step (a); (c) compacting the mixture produced in step (b) to produce a compacted mass; (d) drying the compacted mass to produce the metallurgical composite. 2. The method according to item 1, characterized in that the compression step (c) is carried out by extrusion of the mixture. 3. The method according to item 1, characterized in that the drying step (d) is carried out at or near ambient temperature. 4. Method according to item 1, characterized in that the ore is iron ore or chromite ore. 5. The method according to item 1, characterized in that it is the ore or concentrate is a zinc ore or concentrate. 6. A process for the production of metallurgical composites containing iron ore and treated lignite, peat or biomass, characterized in that it comprises the following steps: (a) action of shear forces and lignite, peat or biomass to produce a plastic mass; (b) mixing finely divided iron ore with the coal, peat or biomass, either during or after step (a); (c) extruding the mixture produced in step (b) to produce a compacted extrudate in the form of pellets; and (d) drying the pellets at ambient temperature. 7. Metallurgical composites, characterized in that they by the method of. one of claims 1 to 6 were prepared. 8. iron melting process, characterized in that by means of the method according to claim 1 to 6 produced composites are heated to a temperature at which the iron ore is reduced to metallic iron. 9. iron melting process, characterized in that by means of the method according to claim 1 to 6 produced composites are heated in a bath of liquid iron. 10. iron melting process, characterized in that produced by the method according to claim 1 to 6 composites a prepyrolysis be subjected to a temperature of about 700 ⁰ C, followed by immersion follows in a bath of liquid iron miteinerTemperaturvon 1 500 ⁰ C. For this 2 pages drawings