METHOD FOR MELTING FERROUS METALS, NON-FERROUS METALS, MACHINING WASTE AND SCRAP AND STEEL

Abstract

A method for melting ferrous metals, non-ferrous metals, machining waste and scrap and steel, includes the following steps of providing a closed container made of a material that is compatible with a melting bath in which it is to be placed and is adapted to contain materials adapted to be used as corrective substances in the melting bath; introducing the corrective substances in the container so as to obtain a closed container which contains the corrective substances; inserting the closed container in the melting bath; and monitoring the melting of the container and the release of the corrective substances in the melting bath.

Claims

1-4. (canceled)

5. A method for melting ferrous metals, non-ferrous metals, machining waste and scrap and steel, the method including the following steps: providing a closed container made of a material that is compatible with a melting bath in which said container is to be placed, said container being configured to contain materials adapted to be used as corrective substances in said melting bath, introducing said corrective substances in said container so as to obtain a closed container which contains said corrective substances, inserting said closed container in said melting bath, and monitoring melting of said container and release of said corrective substances in said melting bath.

6. The method according to claim 5, wherein said corrective substances comprise iron alloys, recarburizing substances, fine products derived from waste of metallurgical processes.

7. The method according to claim 5, wherein said corrective substances comprise materials in small pieces.

8. The method according to claim 5, wherein said corrective substances are inserted in said container in order to also obtain a mixture.

Description

DETAILED DESCRIPTION OF THE DISCLOSURE

[0034] Further characteristics and advantages of the disclosure will become better apparent from the description of a preferred but not exclusive embodiment, of the method according to the disclosure.

[0035] The method according to the disclosure provides for use in foundries of ferrous metals, non-ferrous metals and in steel plants.

[0036] The method is based on the creation of a container, suitable to be closed, of appropriate dimensions, made of new or recycled material, but in any case made of a metal that melts (and therefore allows the contact of a product/material contained therein, for example of a powdery type, which acts as a corrective substance) in the melting bath/liquid so that the container can release its contents without said contents undergoing the processes of heating or contact with oxygen (which causes oxidation).

[0037] In other words, the container is adapted to allow materials/corrective substances (generically referenced hereinafter as corrective substances) to be added to metal in a foundry or in a steel plant to be contained therein and be released as a result of the melting of said container.

[0038] Therefore, the container must be made of a material compatible with the melting bath in which it is to be placed. For example, an aluminum-melting bath must provide a container made of aluminum.

[0039] Such corrective substances (for example also materials in powder form), i.e., iron alloys, recarburizing substances, corrective substances in general and machining waste, are therefore placed in the above mentioned container, which is then inserted in the metal of the melting bath.

[0040] The container ensures that the products contained therein come into contact with the metal already in the semi-liquid state, thus avoiding being exposed to flame or combustion before the metal is molten (both if the metal is ferrous and if it is non-ferrous).

[0041] In this manner one obtains the extension of the time during which the alloys and the recarburizing substances remain protected from the flame and/or from oxidations, thus allowing their chemical function to take place directly in the liquid.

[0042] Possible corrective substances to be introduced in the above mentioned container are listed hereinafter.

[0043] Iron alloysAll iron alloys are selected by manufacturers by means of a screening process that sometimes is repeated in trader storage depots. The larger sizes (10-50 mm or larger) are used in the furnaces. The smaller sizes (3-10 mm) are used as a corrective substance in the ladle, i.e., the tool used to pour the already-molten liquid, and the small sizes (below 3 mm) currently have very low level uses.

[0044] Recarburizing substancesAll products used for the addition of carbon are termed recarburizing substances. Since recarburizing substances are often combustible, their use is very delicate because it is difficult to get them to work in the liquid without burning and, since they are products with low physical strength, without breaking and being aspirated by the extractors.

[0045] Processing Cycles/Scrap/Waste

[0046] Fine products in general, ranging from those that foundries/steel plants themselves produce during processing to those produced by outside companies, for example steel/cast iron powders that currently need to be disposed since they have no applications.

[0047] Moreover, even in the case of extraction systems, all the powders collected by the filters have a content of recarburizing substances/alloys/iron that currently is disposed although it could be reused by means of the container described above.

[0048] It is also possible to provide all fine products in general that might relate to a metallurgical process to be used as corrective substances in powder form.

[0049] Therefore, a series of advantages is obtained. The use of the box is adapted and functional for all types of furnace: electric induction; rotary; cupola; arc and blast furnace.

[0050] The purpose is to increase the yield of iron alloys/metals/recarburizing substances/corrective substances, minimizing waste and scrap to be disposed.

[0051] It also allows the reduction of the ore and of the oxides in general. It also facilitates the management of slag by allowing the introduction of fluxes (limestone flux/lime/CaCO3 and similar products).

[0052] In particular, it allows the use of less valuable titers with less need for harmful emissions during production.

[0053] The container used in the method according to the present disclosure can be seen as a real melting furnace, which implies that the energy derives from its immersion in the melting bath and the heat is transferred by thermal conduction inside said container.

[0054] Consequently, by inserting the desired materials inside the container a chemical reaction is generated which is capable of reducing the oxides.

[0055] The possibility to add a calcareous flux directly in the furnace by means of the container helps to allow deslagging of the siliceous gangue.

[0056] In order to reuse a product with a high percentage of oxide, one proceeds as follows: [0057] the container is filled with oxidized products (be they FeO2; SiO2; MnO2; A102; etcetera in all their forms) and a product with high carbon content, of fossil origin (fossil coal; coke; anthracite), plant-based origin (charcoal), natural origin, chemical origin (petroleum coke; graphite; etcetera), or residual origin (plastic; polymers; etcetera), is added also inside the container. The two products, thanks to the high temperature inside the container immersed in the melting bath, generate a chemical reaction of reduction (FeO2+C=Fe+CO2; SiO2+C=Si+CO2; . . . ); once the melting point has been reached, the container and its contents (Fe; Si; Mn; Al; . . . ) mix with the liquid in which they are immersed.

[0058] Another advantage of the method according to the present disclosure is also the fact that there is a reduced need for pieces of large size and it is possible to use even scrap in powder form, since by being protected by the container casing the materials cannot be aspirated by the filtering systems (saving on the quantity of material and spring the filtering system itself).

[0059] In addition, greater ease in handling is provided since the container can be managed like the raw material and handled by means of mechanical shovels without using large bags or paper bags (with obvious ecological savings in packaging).

[0060] Even further, the container can be filled with different materials at the same time, thus creating a mixture to be added ready-made, which saves in-house work and optimizes management.

[0061] In addition, with the method according to the present disclosure it is possible to use as corrective substances materials normally destined for disposal and it is also possible to obtain full utilization of the dust of filters of extraction systems before disposal of the residue as slag, therefore converting the waste which is essentially recycled, avoiding its disposal.

[0062] Still further, the method according to the present disclosure allows to recover a material destined for disposal, thus providing a recycling process, decreasing the energy and economic consumption due to disposal.

[0063] In practice it has been found that the method according to the disclosure fully achieves the intended aim and objects, since it allows to introduce iron alloys, recarburizing substances, corrective substances in general and machining waste in the metal to be melted.

[0064] The method thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the accompanying claims.

[0065] In practice, the materials used, as well as the contingent shapes and dimensions, may be any according to the requirements and the state of the art.

[0066] The disclosures in Italian Patent Application No. 102020000029678 from which this application claims priority are incorporated herein by reference.