Patent Application
20240278313
The present disclosure relates to a casting mould for producing high-purity copper and to a copper anode for producing high-purity copper.
In a melted state, a plurality of metal materials is poured into moulds to produce workpieces with a pre-determined contour. For example, such a casting process is carried out when producing copper anodes. Such copper anodes are produced in an intermediate step in copper production in order to produce high-purity copper as the end product.
Typical copper production is carried out such that a product with a proportion by weight of more than 90% pure copper is produced from sulfidic copper concentrates (or from copper-containing secondary materials and copper scrap) by melting and oxidisation over several process steps. This raw copper is then processed into copper anodes, which are subjected to an electrolytic refinement in electrolysis baths. A typical processing of the raw copper into anodes is carried out such that the liquid raw copper is poured into metallic moulds. The use of moulds made of copper, which are coated with a release agent before pouring in the liquid raw copper, has in particular proved useful for making a subsequent de-moulding process easier.
The raw copper is formed and solidified with a rectangular geometry of an anode plate (10) with holding arms (2), as shown in
The raw copper is poured into a mould (7), which has a rectangular central first cavity (8) for receiving the liquid raw copper to form the anode plate (10). On the upper part of the mould (7) on the corners of the central first cavity (8), there are two second cavities (9) for receiving the liquid copper, the cavities then forming the holding arms (2) of the anode plate (10) to be cast, as can be seen in
In the refineries, the copper anode (1) is inserted into an electrolysis cell (3), which has a cathode (4) that, depending on the process used, is formed such that it is undissolved or in the form of a master plate having corresponding hanging rods (5). The copper anode (1) is applied with the holding arms (2) to contacts (6) respectively in the form of a conductor rail. The electrolysis cell (3) is filled with an acid solution, and an electric voltage is applied to the contacts (6), in order to generate the electrowinning of copper from the copper anode (1) in the direction of the cathode (4), as shown in
After the electrolysis cycle has ended, the holding arms (2) and a part of the anode plate (10) remain, and together form the rest of the copper anode (1). This material should be completely melted again to form a new copper anode (1) and to continue the complete cycle. The transport and the repeated melting of the anode waste means follow-up costs, which is an important factor in the cost-effectiveness of the production method of the high-purity copper. The mass of the anode waste is important because the effectiveness of the electrolysis method with regards to the separated high-purity copper in relation to the raw copper used is thus limited or reduced. The anode waste should further be handled and transported, such that the weight of the anode waste is in particular of particular importance in the case of manual transport.
In the prior art, different solutions for reducing anode waste are further known. The document DE 11 2012 003 846 T5 describes a system consisting of a re-usable anode hanging device and an anode without holding arms. The quantity of anode waste can unquestionably be reduced, as the anode waste lacks the holding arms, but this will not lead to a reduction in costs. Instead, the use of such an anode hanging device leads to higher follow-up costs, because firstly, an anode without holding arms should be mechanically connected to the anode hanging device before it is used in an electrolysis method, and the anode waste should be separated from the anode hanging device after the electrolysis method finishes. A further cost factor in addition to the mounting process is the production costs and the costs for maintenance and care of the anode hanging device. A further electrode assembly having a hanging device is, for example, known from EP 3 748 041 A1, which has the disadvantage, however, that here too, the hanging device should first be connected to the anode in a mechanical mounting process.
Document DE 11 2015 003 170 T5 describes a hanging rail for carrying an anode without holding arms, which is completely submerged in the electrolyte. Unlike the anode hanging device described in the document DE 11 2012 003 846 T5, which uses rigid holding arms, the hanging rail is equipped with pivotable holding arms. A disadvantage of the hanging rail described is the complex mechanism for keeping the anode secure. Furthermore, in normal conditions of an industrial-scale electrolysis method, significant mechanical loads are applied to the hanging rail during transport and hanging in the electrolysis bath, such that the hanging rail is exposed to significant wear, which leads to increased maintenance complexity. This disadvantage is additionally increased by submerging the hanging rail in the electrolytes, because, depending on the system, encrustations always form in the upper region, and thus here in the region of the hanging rail. In order to guarantee the functionality of the mechanism of the hanging rail, encrustations which arise must be removed, whereby the complexity of maintenance, in particular due to the requisite moveability of the holding arms, is additionally increased.
Document CN 106835196 describes an electrode plate having electrically conducting holders applied on both sides. Conventional metal anodes are hung on these holders on both sides with holding arms. The electrode plate with the anodes hung on both sides is then hung in an electrolysis bath, whereby the anodes are completely submerged in the electrolyte. During the electrolysis process, the hung anodes dissolve slowly in the electrolyte, whereby a state is reached from which the mechanical stability of the holding arms of an anode is no longer guaranteed to support the remaining weight of the partially dissolved anode. The partially dissolved anode thus falls into the electrolysis bath, and must then be removed from the latter to avoid an electrical short-circuit. It is not possible for the anodes to completely dissolve without falling anode waste with this electrode plate.
A further problem with the design of the copper anode (1) is that the copper anode (1) itself heats up to a temperature of approx. 60 degrees in the electrolysis method. This basic heating of the copper anode (1) can increase to an increased temperature of up to 150 degrees in the region of the holding arms (2) in the event of a short-circuit of the copper anode (1) itself or of a neighbouring copper anode (1), whereby the rigidity of the copper anode (1) in the region of the holding arms (2) is reduced in turn. This heating of the holding arms (2) and the associated reduction in rigidity must never lead, however, to the holding arms (2) no longer being able to fulfil their holding function (2) or the copper anode (1) tipping into the electrolysis bath due to the holding arms (2) deforming.
A further problem with such copper anodes is that, due to their large volume, the recesses in the casting moulds provided for forming the holding arms are unequally filled with liquid raw copper when the liquid raw copper is flowing in, as the raw copper carries out oscillating movements when it is flowing in, which, after the raw copper solidifies, leads in turn to holding arms with an uneven outer shape and in particular with different or varying thicknesses.
In an embodiment, the present disclosure provides a casting mould that produces copper anodes for producing high-purity copper. The casting mould has: a first flat cavity, which is delimited by two lateral surfaces aligned in parallel with each other; two second cavities, which are fluidically connected to the first flat cavity, are arranged on different corners on a peripheral side of the first flat cavity, and extend laterally outwardly away from the first flat cavity; and a core. The core is provided centrally in a respective second cavity of the second cavities. The core sub-divides the respective second cavity at least partially into a closed annular shape in the peripheral direction.
Subject matter of the present disclosure will be described in even greater detail below based on the exemplary figures. All features described and/or illustrated herein can be used alone or combined in different combinations. The features and advantages of various embodiments will become apparent by reading the following detailed description with reference to the attached drawings, which illustrate the following:
Against the above background, the present disclosure provides a casting mould, which enables copper anodes having holding arms to be cast with an improved dimensional accuracy. The present disclosure further provides a copper anode that can be cast with improved dimensional accuracy.
According to the present disclosure, a casting mould for producing copper anodes for producing high-purity copper is provided, the casting mould having a first flat cavity, which is delimited by two lateral surfaces aligned in parallel with each other, and two second cavities, which are fluidically connected to the first cavity are arranged on different corners on a peripheral side of the first cavity and extend laterally outwardly away from the first cavity, wherein the principle of the disclosure is that a core is respectively centrally provided in the second cavities, the core sub-dividing the respective second cavity at least partially into a closed annular shape in the peripheral direction. The core forms a barrier or impact wall for the raw copper flowing into the second cavity, the core decelerating the inflow speed of the raw copper and pushing the latter laterally into the annular cavity. The flow of the raw copper can thus be homogenised, which in turn enables a more homogeneous and in particular more complete filling of the second cavity with raw copper. The second cavity is in the form of a channel, and completed via the first cavity to form a closed ring. “Partially” should be understood as meaning that the second cavity need not be completely sub-divided into an annular shape by the core. It is sufficient if the core has a smaller height than the depth of the second cavity, or sub-divides only the inflow opening of the second cavity, and thus acts as a barrier which decelerates the flow of the raw copper, and thus the holding arms are cast with a more homogeneous and in particular more constant thickness.
However, the core can also be dimensioned such that it completely sub-divides the second cavity into a closed annular shape in the peripheral direction. In this case, the flow of the raw copper is decelerated to a maximum and homogenised. Via the core, it is further made possible to cast a copper anode, which has a through opening in the region of the holding arms and which is thus reduced as much as possible in terms of its weight in the region of the holding arms.
According to another aspect of the present disclosure, the core sub-divides the second cavity into a first portion having a closed annular shape and a second flat portion, wherein the second flat portion is arranged laterally on the first portion. Due to its shape, the core thus forms a second flat portion in the second cavity, which additionally leads the flow of the raw copper into the second cavity to be decelerated and homogenised.
According to an aspect of the present disclosure, the core is sub-divided into two partial cores by a gap. The gap practically forms an additional flow connection between the two edges of the annular first portion of the second cavity, and thus enables a further-improved, and in particular more homogeneous and more complete filling of the second cavity with raw copper.
The gap is preferably aligned at an angle of 0 to 45 degrees to a longitudinal central axis of the first cavity. The longitudinal central axis of the first cavity corresponds to the main flow direction of the raw copper flowing into the casting mould. Due to the proposed alignment of the gap, the raw copper flows vectorially into the gap in the main direction in the direction of the main flow direction of the raw copper.
In aspect of the present disclosure, a copper anode for producing high-purity copper is provided, the copper anode having an anode sheet and at least two holding arms is proposed, in which at least one recess is provided in at least one of the holding arms, wherein the holding arms are formed as one part with the anode sheet. The advantage of the disclosure is that, due to the proposed recess in the holding arm, cores must be provided in the cavities of the casting mould to produce the holding arms. During the casting process, these cores form a barrier for the raw copper which is flowing in and reduce the volume of the cavities in the casting mould to be filled with raw copper, which leads in turn to the raw copper flowing into the side conduits next to the core more slowly and more homogeneously. This homogenisation of the flow of the liquid raw copper leads the holding arms to be cast with a more homogeneous thickness than would be the case for casting moulds having the coreless cavities for the holding arms of the copper anodes known in the prior art.
A further advantage of aspects according to the present disclosure is that the proportion of anode waste, and thus the proportion of the raw copper of the copper anode which cannot be dissolved, can be reduced in relation to the raw copper of the entire copper anode by the recess. By implication, the efficacy of the separation, and thus the quantity of the separated high-purity copper in relation to the total amount of the raw copper used in the copper anode can thus be increased. Furthermore, the weight of the copper anode before electrolysis and, particularly advantageously, the weight of the anode waste remaining after electrolysis can thus be reduced. This has advantages during handling and saves transport costs. In addition, the costs for repeated melting are reduced, because the mass of the anode waste to be melted is lower. The copper anode according to the disclosure is deliberately formed as one part with the holding arms and the anode plate, such that the mounting of the holding arms or anode hanging device on the anode plate and the maintenance of the re-usable holding arms or anode hanging device, which are required in the solutions known from the prior art, can be omitted. The recess should thus be understood to mean a depression in the holding arms, which extends into the holding arms in relation to a plane extending through the anode plate. The weight reduction is thus obtained while external dimensions remain the same.
The copper anode according to the present disclosure is further produced by a single casting process with the anode plate and the holding arms, and can then be hung in the electrolysis bath without further processing, and in particular without further mounting steps. In addition to creating the electrical contact, the holding arms serve a central function in handling and holding the copper anode, which weighs 200 to 400 kg, during transport and in the electrolysis bath. For this purpose, the holding arms have a sufficiently high rigidity and load-bearing capacity, which is obtained by a correspondingly thick dimensioning of the holding arms. For this reason, the holding arms moulded as one part onto the anode plate are deliberately formed to be rigid and correspondingly solid in the prior art.
Aspects of the present disclosure include that, despite the central requirement for load-bearing capacity, in particular even with an increased heat input, at least one recess is provided in the holding arms, via which recess the advantages specified above can be obtained. The recess is dimensioned such that the load-bearing capacity of the holding arms, even with an increased heat input, is still sufficient to hold the copper anode as intended during transport and in the electrolysis bath. This is in particular achieved by obtaining the weight reduction via a recess, such that the exterior dimensions, which are particularly important for rigidity, are unchanged.
According to an aspect of the present disclosure, the recess has a shape which corresponds to a scaled-down outer shape of the holding arm. Due to the scaled-down shape of the recess, the respective holding arm is reduced as far as possible in its weight and the mass of the raw copper, but simultaneously weakened as homogeneously as possible, such that the maximum stress in the holding arm during holding and handling of the copper anode can be reduced to as low and as homogeneous a value as possible.
According to an aspect of the present disclosure, the recess is at least partially closed by a supporting wall. The supporting wall forms an additional rigidity of the holding arm in the region of the recess, whereby an improved compromise between the two requirements, specifically the required rigidity and the reduction in weight, can be realised. The thickness of the supporting wall is thus an additional available design parameter for obtaining the necessary load-bearing capacity of the holding arm.
According to an aspect of the present disclosure, the depth of the recess down to the supporting wall corresponds to at least half of the thickness of the holding arm perpendicular to a plane extending through the anode sheet. The supporting wall thus has a thickness which corresponds at maximum to half of the thickness of the holding arm. A substantial weight reduction with a simultaneously sufficient rigidity of the holding arm can thus be obtained.
The weight reduction can be further increased by forming the recess at least partially as a through opening. Furthermore, the through openings which are thus made can additionally be used to transport the copper anode by hanging corresponding hooks or hanging devices.
According to an aspect of the present disclosure, the recess is sub-divided into two partial recesses by means of a stiffening rib. The stiffening rib practically forms a bar which subdivides the recess, the bar stiffening the holding arm in the manner of a framework, whereby the rigidity of the holding arm can be significantly influenced by the thickness and alignment of the stiffening rib.
According to an aspect of the present disclosure, the stiffening rib is aligned at an angle of 0 degrees to 45 degrees to a longitudinal central axis of the anode sheet running between the holding arms. Due to the proposed alignment, the holding arms are specifically stiffened against the tensile stresses caused by gravity acting on the copper anode in the hanging arrangement of the copper anode.
According to an aspect of the present disclosure, the recess is dimensioned such that the holding arms at least partially have a greater wall strength on their side of the electrical contact surface in a plane extending through the anode sheet than on the side which does not have an electrical contact surface. The advantage of this aspect is that the holding arm has a thicker wall thickness in the region of the introduction of the electrical current flow, such that the current flow density in the holding arm can thus be specifically reduced in this region, while the side on which no contact surface is provided is deliberately formed to be thinner for the purpose of saving more weight. If the copper anode is provided with the side of the holding arm having the electrical contact surface for contacting an external conductor rail, the holding arm is thus additionally stiffened on its underside in a targeted manner, in which underside the tensile stresses act, the latter being decisive for the deformation of the holding arm when the copper anode is held on the conductor rail. Due to the corresponding thicker dimensions of the holding arm on this side, the acting maximum tensile stresses in the holding arm can be reduced, such that the load-bearing capacity of the latter can be increased.
Aspects of the present disclosure explained in more detail in the following with reference to preferred embodiments with reference to the attached figures.
In
The copper anode 1 which has been cast in the casting mould 7, which copper anode can be seen in
Due to the shape of the second cavities 9 with the central cores 20, the holding arms 2 respectively have an upper edge 14 formed to correspond to the shape of the first portion 24 in the form of a channel and a lower edge 13, which are connected to each other on their ends and enclose a recess 11 between them, which is formed in shape by the shape of the core 20. The recesses 11 are closed in the depiction on their rear sides by supporting walls 15, which are formed by the shape of the flat second portions 25 of the second cavities 9. The supporting walls 15 are formed by flat walls which are aligned in parallel with the plane extending through the anode sheet 10. The plane extending through the anode sheet 10 corresponds to the depiction plane and is described in the following only as plane I, which also applies to the subsequent exemplary embodiments.
As can be seen from
In the casting mould 7 known in the prior art, which can be seen in
The recesses 11 are formed by depressions in the holding arms 2 and additionally reduce the quantity of raw copper poured into the holding arms 2. The exterior dimensions of the holding arms 2 are deliberately not reduced, because a particularly high load-bearing capacity and rigidity of the holding arms 2 can be obtained via correspondingly large exterior dimensions. The lower edge 13 and the upper edge 14 of the holding arms 2 have a substantially constant wall thickness B in the plane I, such that the recess 11 has a scaled-down shape in relation to the exterior shape of the holding arms 2. However, the lower edge 13 can also have a slightly greater wall strength, such that a correspondingly flat contact surface 12 can then be created via milling or sanding of the surface without the load-bearing capacity of the holding arms 2 thus being reduced to such an extent that they can no longer carry out their holding function.
The holding arms 2 are reduced in weight by the recesses 11 and simultaneously stiffened by the supporting walls 15. The supporting walls 15 are aligned in parallel with the plane I of the anode sheet 10, such that they stiffen the holding arms 2 as much as possible against the tensile stresses acting in the plane I. They thus have the required load-bearing capacity for handling and supporting the copper anode 1, while their mass is simultaneously reduced, such that the waste portion of the copper anode 1 is reduced after the electrolysis process with the advantages described above. Due to their arrangement in parallel with the plane I, the supporting walls 15 are aligned in parallel with the gravity acting on the copper anode 1 when lifting the copper anode 1 and when hanging the copper anode 1 in the electrolysis bath, and thus cause a maximum stiffening of the holding arms 2 against the pressing forces exerted via the contact surface 12 when supporting the copper anode 1.
In
In
In
For this purpose, the core 20 is sub-divided by a gap 21 into two partial cores 22 and 23 in the second cavities 9. The stiffening rib 17 is cast through the gap 21, the stiffening rib separating the partial through openings 18 and 19 formed by the partial cores 22 and 23 from each other.
The decisive advantage of the solution according to the disclosure is that the weight of the anode waste can be reduced and the efficacy of the electrolysis method in relation to the raw copper used can be very easily increased without sacrificing the advantage of the significantly more cost-efficient manufacture of the copper anode 1 as one part with the anode plate 10 having the holding arms 2. The recesses 11 are deliberately designed as depressions in the holding arms 2, and thus as cavities extending from a flat surface of the holding arms 2 into the holding arms 2, such that a high stiffness of the holding arms 2 caused by the retained exterior shape can be generated while simultaneously reducing the weight of the holding arms 2 via the recesses 11 provided therein. The recesses 11 are deliberately provided in the holding arms 2, such that the quantity of the high-purity copper to be produced is not reduced, because the holding arms 2 are not destroyed in the electrolysis process and thus do not contribute to the extraction of the high-purity copper.
While subject matter of the present disclosure has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. Any statement made herein characterizing the invention is also to be considered illustrative or exemplary and not restrictive as the invention is defined by the claims. It will be understood that changes and modifications may be made, by those of ordinary skill in the art, within the scope of the following claims, which may include any combination of features from different embodiments described above.
The terms used in the claims should be construed to have the broadest reasonable interpretation consistent with the foregoing description. For example, the use of the article “a” or “the” in introducing an element should not be interpreted as being exclusive of a plurality of elements. Likewise, the recitation of “or” should be interpreted as being inclusive, such that the recitation of “A or B” is not exclusive of “A and B,” unless it is clear from the context or the foregoing description that only one of A and B is intended. Further, the recitation of “at least one of A, B and C” should be interpreted as one or more of a group of elements consisting of A, B and C, and should not be interpreted as requiring at least one of each of the listed elements A, B and C, regardless of whether A, B and C are related as categories or otherwise. Moreover, the recitation of “A, B and/or C” or “at least one of A, B or C” should be interpreted as including any singular entity from the listed elements, e.g., A, any subset from the listed elements, e.g., A and B, or the entire list of elements A, B and C.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2021 115 671.8 | Jun 2021 | DE | national |
This application is a U.S. National Phase application under 35 U.S.C. § 371 of International Application No PCT/EP2022/066338, filed on Jun. 15, 2022, and claims benefit to German Patent Application No. DE 10 2021 115 671.8, filed on Jun. 17, 2021. The International Application was published in German on Dec. 22, 2022 as WO 2022/263526 A1 under PCT Article 21(2).
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/066338 | 6/15/2022 | WO |
