Patent Description:
More specifically, the invention proposes the development of a system and method for refining copper alloys, which, due to its particular arrangement, achieves greater energy performance and greater efficiency in a copper refining process.

In the state of the art, it is known that due to climate change, the circular economy must be implemented and products with a minimum carbon footprint in their preparation must be used.

Modern society requires the use of copper for its development, and currently <NUM>% of copper consumption comes from recycled material. There are currently two industrial processes for recovering recycled copper, the pyrometallurgical process and the hydrometallurgical process. Undoubtedly, the most efficient one from the environmental standpoint is the pyrometallurgical process. Examples of a method for refining copper alloys can be found in <CIT>, <CIT> and <CIT>.

Nowadays, there are two pyrometallurgical technologies for recycling copper that use raw material with copper content higher than <NUM>%, these being the use of the traditional reverberatory furnace or the use of the so-called "Cosmelt Process", invented by the same applicant in <NUM>.

The reverberatory furnace is characterised by working in phases, i.e., loading, melting, oxidation, refining, reduction and smelting phase. To be efficient in the refining phase, the furnace requires a large surface of liquid copper.

In an in-depth analysis of this process and with a view to sustainability, the following strengths in the use of the traditional reverberatory furnace can be defined:.

The "Cosmelt Process" is characterised by working continuously. Loading and melting is carried out in a vertical furnace with high energy efficiency, with the loading door at the top and the burners at the bottom of the furnace. The furnace is filled with recycled material, casting in the bottom and transferring the liquid copper to a set of refining boxes with the incorporation of additives and with porous plugs for the injection of oxygen to oxidise the bath. The set of boxes work continuously until they feed two furnaces for homogenising and reducing purified liquid copper that work alternately to maintain a constant flow of purified liquid copper.

In an in-depth analysis of this "Cosmelt Process" and with a view to sustainability, the following strengths can be defined:.

The present invention, due to its particular arrangement, contributes to improving energy performance and greater efficiency in the recycled copper treatment processes known in the state of the art.

The present invention has been developed to provide a copper alloy refining system, comprising a vertical furnace, an oxidising furnace, a refining furnace, a reducing furnace and a smelting furnace, arranged sequentially one after the other in this order and mutually linked for the passage therethrough of molten copper resulting from a copper load or copper alloy load introduced into the vertical furnace; wherein the vertical furnace has a melting capacity for the introduced copper load, wherein the oxidising furnace is enabled for oxygen exchange with the molten copper coming from the vertical furnace, wherein the refining furnace is enabled to add additives to the molten copper coming from the oxidising furnace, wherein the reducing furnace is enabled to reduce the molten copper coming from the refining furnace, wherein the smelting furnace is enabled to receive the molten copper coming from the reducing furnace.

In addition, in the copper alloy refining system, the vertical furnace and the smelting furnace have the capacity for continuous output of molten copper, and the oxidising furnace, the refining furnace and the reducing furnace are provided for discontinuous filling and emptying.

The copper alloy refining system, the oxidising furnace, the refining furnace and the reducing furnace have the same volumetric capacity, which is six times higher than the volumetric capacity of the vertical furnace and two times higher than the volumetric capacity of the smelting furnace.

In addition, in the copper alloy refining system, the oxidising furnace has an arrangement where a ratio between the free surface (S) of the molten copper and the height (A) of the same molten copper is eight.

In addition, in the copper alloy refining system, the refining furnace has an arrangement where a ratio between the free surface (S) of the molten copper and the height (A) of the same molten copper is higher than fifteen.

In addition, in the copper alloy refining system, the reducing furnace has an arrangement where a ratio between the free surface (S) of the molten copper and the height (A) of the same molten copper is two.

Alternatively, in the copper alloy refining system, the vertical furnace allows the copper load to be introduced through its upper portion, and liquid copper and slag resulting from the melting of the copper load to exit through a lower side. Alternatively, in the copper alloy refining system, the oxidising furnace incorporates an injection of oxygen through lances or porous plugs. Alternatively, in the copper alloy refining system, the refining furnace incorporates porous plugs.

Alternatively, in the copper alloy refining system, the reducing furnace incorporates an injection of reducing agent through lances or porous plugs.

A copper alloy refining method, comprising the following successive steps:.

In the copper alloy refining method, melting, oxidation, refining, reduction and smelting take place respectively in a vertical furnace, an oxidising furnace, a refining furnace, a reducer and a smelting furnace, wherein the oxidising furnace, the refining furnace and the reducing furnace have the same volumetric capacity, which is six times higher than the volumetric capacity of the vertical furnace and two times higher than the volumetric capacity of the smelting furnace.

In addition, in the copper alloy refining method, oxidation takes place in an oxidising furnace that has an arrangement where a ratio between the free surface (S) of the molten copper and the height (A) of the same molten copper is eight.

In addition, in the copper alloy refining method, refining takes place in a refining furnace that has an arrangement where a ratio between the free surface (S) of the molten copper and the height (A) of the same molten copper is higher than fifteen.

In addition, in the copper alloy refining method, reduction takes place in a reducing furnace that has an arrangement where a ratio between the free surface (S) of the molten copper and the height (A) of the same molten copper is two.

In addition, in the copper alloy refining method, melting, oxidation, refining, reduction and smelting take place respectively in a vertical furnace, an oxidising furnace, a refining furnace, a reducer and a smelting furnace, wherein the treatment capacity in tonnes per hour of the oxidising furnace, the refining furnace and the reducing furnace are equal and six times higher than the treatment capacity in tonnes per hour of the vertical furnace and two times higher than the treatment capacity in tonnes per hour of the smelting furnace.

In addition, in the copper alloy refining method, the vertical furnace continuously discharges the liquid copper in the oxidising furnace, the oxidising furnace discharges the liquid copper in the refining furnace every six hours, the refining furnace discharges the liquid copper in the reducing furnace every six hours, the reducing furnace discharges the liquid copper in the smelting furnace every three hours, and the smelting furnace continuously delivers the liquid copper.

In addition, the copper alloy refining method is carried out by a described copper alloy refining system.

As a result of the present invention, it is possible to improve energy performance and greater efficiency in the recycled copper treatment processes known in the state of the art.

Other features and advantages of the system and method for refining copper alloy will become apparent from the description of a preferred, but non-exclusive embodiment, illustrated by way of non-limiting example in the attached drawings, in which:.

The present invention relates to a copper alloy refining system, which, due to its particular arrangement, provides notable advantages to the state of the art.

As shown schematically in <FIG>, the copper alloy refining system comprises a vertical furnace <NUM>, an oxidising furnace <NUM>, a refining furnace <NUM>, a reducing furnace <NUM> and a smelting furnace <NUM>, which are arranged sequentially one after the other in this order, and mutually linked for the passage therethrough of molten copper <NUM> resulting from a copper load <NUM>, copper alloy load or copper scrap load introduced into the vertical furnace <NUM>.

The copper load <NUM> introduced into the copper alloy refining system of the invention and the molten copper <NUM> resulting from its melting in the vertical furnace <NUM> therefore follows a sequential path through the vertical furnace <NUM>, the oxidising furnace <NUM>, the refining furnace <NUM>, the reducing furnace <NUM> and the smelting furnace <NUM> in this order.

As shown in <FIG>, the vertical furnace <NUM> is arranged at the beginning of the copper alloy refining system of the invention, and it is where the copper load <NUM> to be treated is introduced, and it has a melting capacity for said copper load <NUM> introduced for its transformation into liquid copper <NUM>. <FIG> represents a possible arrangement of the vertical furnace <NUM>, with an introduction of the copper load <NUM> through its upper portion, and a continuous output of liquid copper <NUM> resulting from its melting and slag <NUM> through a lower side.

Next, the liquid copper <NUM> coming from the same molten copper load <NUM> passes to the oxidising furnace <NUM>, which is enabled for oxygen exchange with the molten liquid copper <NUM> coming from the vertical furnace <NUM>.

Afterward, the liquid copper <NUM> passes to the refining furnace <NUM>, which is in turn enabled to add additives to the liquid copper <NUM> coming from the oxidising furnace <NUM>.

Subsequently, the liquid copper <NUM> passes to the reducing furnace <NUM>, which is enabled to reduce the liquid copper <NUM> coming from the refining furnace <NUM>.

Lastly, the liquid copper <NUM> passes to the smelting furnace <NUM>, which is enabled to receive the liquid copper <NUM> coming from the reducing furnace <NUM>, and its continuous delivery.

The copper alloy refining system of the proposed invention also has a number of particularities.

On the one hand, the oxidising furnace <NUM>, the refining furnace <NUM> and the reducing furnace <NUM> have the same volumetric capacity.

Furthermore, said same volumetric capacity of the oxidising furnace <NUM>, the refining furnace <NUM> and the reducing furnace <NUM> is six times higher than the volumetric capacity of the vertical furnace <NUM>, and is simultaneously two times higher than the volumetric capacity of the smelting furnace <NUM>. Therefore, the volumetric capacity of the smelting furnace <NUM> is three times higher than that of the vertical furnace <NUM>.

On the other, as shown schematically in <FIG>, the oxidising furnace <NUM> has an arrangement where a ratio between the free surface S of the molten liquid copper load <NUM> and the height A of the same molten liquid copper load <NUM> is eight, in other words, S(m<NUM>)/A(m)=<NUM>, obviously using coherent units of surface and height, metres in this case.

This detail of the oxidising furnace <NUM> provides the advantage of having a high capacity for oxygen exchange with copper, as well as sufficient surface for the exchange of copper with fluxes. The oxidising furnace <NUM> can also incorporate an injection of oxygen through lances or porous plugs to allow good slagging.

In the same manner, as shown schematically in <FIG>, the refining furnace <NUM> has an arrangement where a ratio between the free surface S of the liquid copper <NUM> and the height A of the same liquid copper load <NUM> is higher than fifteen, in other words, S(m<NUM>)/A(m)><NUM>, obviously using coherent units of surface and height, metres in this case.

This detail of the refining furnace <NUM> provides the advantage of a high capacity for surface exchange, with a low height of liquid copper <NUM> and a large section, with great ease of slagging and great movement of the copper through porous plugs, allowing the loading of additives and good automatic slagging.

Likewise, <FIG> also shows that the reducing furnace <NUM> has an arrangement where a ratio between the free surface S of the molten liquid copper <NUM> and the height A of the same molten copper load is two, in other words, S(m<NUM>)/A(m)=<NUM>, obviously using coherent units of surface and height, metres in this case.

This detail of the reducing furnace <NUM> entails the advantage of a high capacity for reduction exchange, with a large height of liquid copper <NUM> and a small section.

The reducing furnace <NUM> can also have an injection of reducing agent through lances or porous plugs.

The copper alloy refining system of the present invention avoids the drawbacks of the pyrometallurgical processes known in the state of the art, allows for operation and continuous casting called Circular Copper Smelter (CCS) by the applicant himself, and allows for circular copper of all types with a minimum copper content of <NUM>% to be processed, incorporating the advantages and eliminating the limitations of the current processes known in the state of the art (reverberation and "Cosmelt Process").

The copper alloy refining system of the present invention optimises each furnace based on the phase that is required to purify circular copper, thus obtaining greater energy performance and greater efficiency in each copper refining process.

<FIG> shows the vertical furnace <NUM> in greater detail, wherein the copper load <NUM> to be treated in its upper portion and an outlet for liquid copper <NUM> and slag <NUM> through a lower side can be seen. The combustion burners <NUM> are displaced to the rear and allow the generation of a pool of liquid copper <NUM> that facilitates the transfer and exit of the slag <NUM> to the oxidising furnace <NUM>.

In the case, for example, of wanting to continuously refine X tonnes/hour of copper recycling in the copper alloy refining system of the invention, the melting treatment capacity of the vertical furnace <NUM> will then be X tonnes/hour.

Therefore, and according to the aforementioned detail that the volumetric capacity of the oxidising furnace <NUM>, the refining furnace <NUM> and the reducing furnace <NUM> is six times higher than the volumetric capacity of the vertical furnace <NUM>, the treatment capacity of the oxidising furnace <NUM> is 6X, considering X as the continuous treatment capacity in tonnes/hour for refining copper recycling by the vertical furnace <NUM>. The oxidising furnace <NUM> continuously receives the liquid copper <NUM> from the vertical furnace <NUM>, and the liquid copper <NUM> is emptied and delivered to the refining furnace <NUM> every six hours.

Next, the refining furnace <NUM> also with a treatment capacity of 6X, after loading the liquid copper <NUM> from the oxidising furnace <NUM>, empties the liquid copper <NUM> to the reducing furnace <NUM> every six hours.

The treatment capacity of the reducing furnace <NUM> is also 6X, receiving liquid copper <NUM> from the refining furnace <NUM> every six hours.

However, taking into account that the volumetric capacity of the smelting furnace <NUM> is half that of the reducing furnace <NUM>, the smelting furnace <NUM> has a treatment capacity of 3X.

Therefore, the reducing furnace <NUM> discharges the liquid copper <NUM> to the smelting furnace <NUM> every three hours, and the liquid copper <NUM> subsequently exits the smelting furnace <NUM> continuously.

In other words, the vertical furnace <NUM> and the waiting and smelting furnace <NUM> are provided for continuous operation and transfer of the liquid copper <NUM>, while the oxidising furnace <NUM>, the refining furnace <NUM> and the reducing furnace <NUM> are provided for discontinuous filling and emptying.

The invention further includes a copper alloy refining method. In one embodiment, said method of the invention can also be carried out by using the copper alloy refining system described above and also included in the invention.

The copper alloy refining method included in the invention comprises the following successive steps, as represented schematically in <FIG>:.

The said copper alloy refining method, melting <NUM>, oxidation <NUM>, refining <NUM>, reduction <NUM> and smelting <NUM> take place respectively in a vertical furnace <NUM>, an oxidising furnace <NUM>, a refining furnace <NUM>, a reducer <NUM> and a smelting furnace <NUM>, wherein the oxidising furnace <NUM>, the refining furnace <NUM> and the reducing furnace <NUM> have the same volumetric capacity, which is six times higher than the volumetric capacity of the vertical furnace <NUM> and two times higher than the volumetric capacity of the smelting furnace <NUM>.

Also in said copper alloy refining method, the oxidising furnace <NUM> where oxidation <NUM> takes place has an arrangement where a ratio between the free surface (S) of the molten copper <NUM> and the height (A) of the same molten copper <NUM> is eight.

Also in the same copper alloy refining method, the refining furnace <NUM> where refining <NUM> takes place has an arrangement where a ratio between the free surface (S) of the molten copper <NUM> and the height (A) of the same molten copper <NUM> is higher than fifteen.

Also in the same copper alloy refining method, reduction <NUM> takes place in a reducing furnace <NUM> that has an arrangement where a ratio between the free surface (S) of the molten copper <NUM> and the height (A) of the same molten copper <NUM> is two.

In this copper alloy refining method of the invention, melting <NUM>, oxidation <NUM>, refining <NUM>, reduction <NUM> and smelting <NUM> take place respectively in a vertical furnace <NUM>, an oxidising furnace <NUM>, a refining furnace <NUM>, a reducer <NUM> and a smelting furnace <NUM>, wherein the treatment capacity in tonnes per hour of the oxidising furnace <NUM>, the refining furnace <NUM> and the reducing furnace <NUM> are equal and six times higher than the treatment capacity in tonnes per hour of the vertical furnace <NUM> and two times higher than the treatment capacity in tonnes per hour of the smelting furnace <NUM>.

Furthermore, in the copper alloy refining method of the invention, the vertical furnace <NUM> continuously discharges the liquid copper <NUM> in the oxidising furnace <NUM>, the oxidising furnace <NUM> discharges the liquid copper <NUM> in the refining furnace <NUM> every six hours, the refining furnace <NUM> discharges the liquid copper <NUM> in the reducing furnace <NUM> every six hours, the reducing furnace <NUM> discharges the liquid copper <NUM> in the smelting furnace <NUM> every three hours, and the smelting furnace <NUM> continuously delivers the liquid copper <NUM>.

Claim 1:
A copper alloy refining system, characterised in that it comprises a vertical furnace (<NUM>), an oxidising furnace (<NUM>), a refining furnace (<NUM>), a reducing furnace (<NUM>) and a smelting furnace (<NUM>), arranged sequentially one after the other in this order and mutually linked for the passage therethrough of molten copper (<NUM>) resulting from a copper load (<NUM>) or copper alloy load introduced into the vertical furnace (<NUM>); wherein the vertical furnace (<NUM>) has a melting capacity for the introduced copper load (<NUM>), wherein the oxidising furnace (<NUM>) is enabled for oxygen exchange with the molten copper (<NUM>) coming from the vertical furnace (<NUM>), wherein the refining furnace (<NUM>) is enabled to add additives to the molten copper (<NUM>) coming from the oxidising furnace (<NUM>), wherein the reducing furnace (<NUM>) is enabled to reduce the molten copper (<NUM>) coming from the refining furnace (<NUM>), wherein the smelting furnace (<NUM>) is enabled to receive the molten copper (<NUM>) coming from the reducing furnace (<NUM>); and wherein the oxidising furnace (<NUM>), the refining furnace (<NUM>) and the reducing furnace (<NUM>) have the same volumetric capacity, which is six times higher than the volumetric capacity of the vertical furnace (<NUM>) and two times higher than the volumetric capacity of the smelting furnace (<NUM>).