How to recover metals from electronic waste

Abstract

The present invention relates to a method for recovering metals of Groups 8 to 14, in particular blister copper, comprising the steps of: i) providing and melting a feed mixture including electronic waste in a melting reactor to form a first melt having a first metal phase and a first slag phase; ii) removing the first slag phase from the melting reactor; iii) smelting the remaining first metal phase with an oxygen-containing gas, optionally with the addition of a copper-containing residue, to form a second copper-rich slag phase; iv) optionally removing a second slag phase and repeating the steps; v) removing the refined first metal phase from the melting reactor; and vi) adding a further feed mixture comprising electronic waste to the remaining second copper-enriched slag phase and repeating process steps i) to vi); The present invention relates to the method comprising the steps of:

Description

[Technical field]

[0001] The present invention relates to a method for recovering group 8 to group 14 metals from electronic waste. [Background technology]

[0002] Such methods are known in principle in the prior art. For example, on the Internet at the address https: / / www.totalmateria.com there is the article “Ausmelt / Isasmelt Matte Smelting: Part One”, which describes a method for recycling copper-containing residues. In particular, the method provides for introducing such residues into a cylindrical furnace vessel from above and exposing them inside this vessel to oxygen-enriched air introduced into the furnace from above with the aid of a top lance. The introduced residues are thus melted and a metallic phase with a floating slag phase arises in the furnace. Both of these heterophases are periodically tapped out of the vessel together. The metallic phase with a high copper proportion is only separated from the slag phase outside the cylindrical furnace vessel.

[0003] Furthermore, Chinese Patent Publication CN108224433A (Patent Document 1) discloses recycling e-waste, especially for the purpose of recovering copper. The method contemplates that e-waste as raw material is first weighed, mixed and shredded, and then introduced into a preheated rotary furnace, where it is exposed to oxygen and gaseous fuel. The raw material is then melted into a metal phase and a slag phase. After exposure to oxygen, the metal phase and the slag phase are tapped separately.

[0004] European Patent Application Publication No. EP 1609877 A1 discloses a method for batchwise processing of metal-containing residues, particularly e-waste, in a rotary reactor. The feedstock, i.e. particularly e-waste, consists essentially of pieces of a size such that it allows continuous loading during operation. In the reactor, the material is melted, resulting in a sorted material that is essentially free of organic matter, since the original organic part of the feedstock is combusted during melting.

[0005] This background indicates that there remains a need for improved methods for recovering metals from e-waste. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Chinese patent application CN108224433A [Patent Document 2] European Patent Application Publication No. EP1609877A1 [Non-patent literature]

[0007] [Non-Patent Document 1] https: / / www.totalmateria.com, “Ausmelt / Isasmelt Matte Smelting: Part One” Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention is therefore based on the problem of providing an improved process for recovering metals from groups 8 to 14 over the prior art, in particular a process in which at least one of the metals from groups 8 to 14 is quantitatively recovered from used electronic waste.

[0009] According to the invention, this problem is solved by a method having the features of claim 1.

[0010] Further advantageous embodiments of the invention are set forth in the dependent claims. The features individually set forth in the dependent claims can be combined with one another in any scientifically and technically meaningful manner to define further embodiments of the invention. Furthermore, the features set forth in the claims are more particularly defined and explained in the detailed description of the invention, in which further preferred embodiments of the invention are set forth.

[0011] The process according to the invention for recovering metals of groups 8 to 14, preferably groups 8 to 11 and 14, in particular blister copper, comprises the following steps: i) providing and melting in a melting reactor a feed mixture including electronic waste to form a first melt having a first metal phase and a first slag phase; ii) removing the first slag phase from the melting reactor; iii) smelting the remaining first metal phase with an oxygen-containing gas, optionally with the addition of a copper-containing residue, to form a second copper-rich slag phase; iv) optionally removing the second slag phase and repeating step iii); v) removing the refined first metal phase from the melting reactor; and vi) adding a further feed mixture comprising electronic waste to the remaining second copper-enriched slag phase and repeating process steps i) to vi); Includes.

[0012] Surprisingly, it has been found that the blister copper present in the second copper-rich slag phase, enriched in the second slag phase as copper oxide during refining / conversion, is converted into the next new first metal phase as a result of the prevailing reducing conditions in the melting reactor during melting of the next batch or further feed mixture, and can be directly recovered therefrom. By continuously continuing the process, therefore, only a slag phase that is almost depleted in copper is obtained. Due to this in situ recovery of the oxidized copper, the obtained metal phase therefore has an increased blister copper content. In addition, it has been surprisingly found that by recycling the still liquid residual slag or the second copper-rich slag phase, the overall process has an improved energy balance, and the chemically bound oxygen of the copper oxide of the residual slag supports the ongoing combustion reaction with each additional feed mixture.

[0013] In order to obtain a slag that is as molten as possible and therefore not too viscous, the entire process is carried out at a temperature of at least 1150° C., more preferably at least 1200° C., even more preferably at least 1225° C., most preferably at a temperature of 1250° C. However, the temperature of the process must not exceed a maximum temperature for plant technical reasons. The maximum temperature of the process is therefore 1400° C., preferably a maximum temperature of 1375° C., more preferably a maximum temperature of 1350° C., most preferably a maximum temperature of 1325° C.

[0014] The method according to the invention is intended for the pyrometallurgical processing of electronic waste, so that in principle up to 100% by weight of electronic waste can be used in the feed mixture. The term "electronic waste" is understood in the sense of the present invention to mean, on the one hand, electronic waste equipment as defined in accordance with EU Directive 2002 / 96 / EG. The equipment categories covered by this Directive concern: major household appliances; small household appliances; IT- and telecommunications equipment; entertainment appliances; lighting equipment; electric and electronic tools (excluding stationary industrial tools); electric toys and sports and leisure equipment; medical devices (excluding implants and infectious products); monitoring and control equipment; and complete and / or (partially) dismantled parts from the range of automatic dispensers. For the individual products classified in the corresponding equipment categories, please refer to Annex IB of the Directive.

[0015] Additionally, the term "e-waste" is understood to refer to residues and / or by-products from e-waste processing.

[0016] The electronic waste may be present in the feed mixture in the form of individual pieces and / or in the form of a mixture of individual components.

[0017] Optionally, copper-containing residues can be added to the process in step iii) for cooling purposes. In the sense of the present invention, the term "copper-containing residues" is understood to mean all copper-containing residues which contain a significant proportion by weight of copper and which are not subject to the above-mentioned EU Directive 2002 / 96 / EG, such as metallic copper waste, copper runners and / or dry copper-containing sludges and / or dusts from copper- and / or copper alloy production and / or processing.

[0018] Electronic waste essentially comprises organic content, e.g. in the form of hydrocarbon-containing components, such as, inter alia, plastics, and metallic components, such as, inter alia, elements selected from the group comprising iron, ruthenium, osnium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium, mercury, aluminium, gallium, indium, lead and / or tin and optionally antimony, titanium and / or yttrium.

[0019] However, the organic content in the form of hydrocarbon-containing components must not be too low in the feed mixture, otherwise sufficient combustion reactions will not occur. Therefore, the proportion of hydrocarbon-containing components in the e-waste or feed mixture is preferably at least 5.0 wt.%, more preferably at least 10.0 wt.%. The e-waste or feed mixture is limited in terms of a maximum content, which is therefore preferably at most 80.0 wt.%, more preferably at most 70.0 wt.%, even more preferably at most 60.0 wt.%, and most preferably at most 50.0 wt.%.

[0020] In cases where the available e-waste does not contain the desired proportion of organic content and therefore does not have the necessary combustion value, a suitable amount of conventional fuel can be added to the feed mixture, such as coal, coke, and fuel gases, such as natural gas, propane, hydrogen, or other gases known to those skilled in the art.

[0021] The solid and / or gaseous fuels can be fed through a feed device, such as a lance or one or more nozzles, that extend into the melt reactor.

[0022] The melting of the feed mixture according to step i) is generally carried out in the presence of atmospheric oxygen. The addition of atmospheric oxygen, possibly in the form of oxygen-enriched air or in the form of an oxygen-containing gas, which is continuously introduced into the melting reactor during the melting process, causes the combustion of the hydrocarbons from the fed feed mixture. In this case, the combustion and therefore the heat generation can be precisely controlled by the amount of oxygen added. In principle, the higher the proportion of hydrocarbons in the feed mixture, the lower the oxygen content of the added combustion air can be. However, due to the composition of the air, this is always at least 20.5% by volume.

[0023] When the proportion of hydrocarbons in the feed mixture is low, the melting process can be carried out with an oxygen content of the combustion air of up to 100% by volume.

[0024] Advantageously, step i) of the method according to the invention is assisted by selectively blowing in an oxygen-containing gas in order to constantly create a reducing atmosphere at the surface of the melt. The reaction is thus carried out by the formation of CO from the hydrocarbons. 2 and H 2 Complete combustion to O does not occur, CO, H 2 The content of is also adjusted to be formed in the process gas.

[0025] When the feed mixture is melted, a metallic phase forms containing blister copper and other heavy metals, particularly lead (Pb), tin (Sn), zinc (Zn), nickel (Ni), and the precious metals gold (Au) and silver (Ag). The e-waste mineral components of the feed mixture form a lighter slag phase along with oxides of oxygen-affinity elements, such as lead (Pb), tin (Sn), nickel (Ni), iron (Fe), silicon (Si), titanium (Ti), sodium (Na), calcium (Ca), aluminum (Al), magnesium (Mg), and the like, among others.

[0026] Through the completeness of combustion at the melt surface, the heat input at the melt surface and the degree of oxidation of the accompanying elements are simultaneously controlled. In this way, undesirable components such as elemental aluminum or silicon are selectively oxidized and precisely transferred to the slag phase. The resulting metal phase is therefore characterized by a residual content of both elements of <0.1% by weight, respectively.

[0027] If the oxygen supply to the process in step i) is too high, the first slag phase can be advantageously reduced with a reducing agent, whereby the first slag phase is purified and post-reduced, so that any heavy metal oxides present, such as SnO, Cu, 2 O, NiO, PbO and / or ZnO can be converted to their metallic forms and therefore to the metallic phase.

[0028] As melting reactor, preferably a metallurgical vessel is considered, for example a tiltable rotary converter, in particular a so-called Top Blowing Rotary Converter (TBRC), or a tiltable Stand Converter. In an advantageous embodiment, the metallurgical vessel comprises a first tapping port for tapping the metallic phase and / or a second tapping port for tapping the slag phase. In this case, the tapping port for tapping the metallic phase is advantageously arranged at the bottom and / or at the side wall of the melting reactor in question, so that the metallic phase can be removed via the tapping port.

[0029] In one advantageous embodiment, the feed mixture, and in particular each feed mixture, comprises electronic waste in an amount of at least 10.0 wt.-%, more preferably at least 15.0 wt.-%, even more preferably at least 20.0 wt.-%, even more preferably at least 25.0 wt.-%, even more preferably at least 30.0 wt.-%, even more preferably at least 35.0 wt.-%, even more preferably at least 40.0 wt.-%, even more preferably at least 45.0 wt.-%, even more preferably at least 50.0 wt.-%, even more preferably at least 55.0 wt.-%, even more preferably at least 60.0 wt.-%, even more preferably at least 65.0 wt.-%, even more preferably at least 70.0 wt.-%, even more preferably at least 80.0 wt.-%, even more preferably at least 90.0 wt.-%, and most preferably at least 95.0 wt.-%, based on the total feed mixture.

[0030] In yet another advantageous embodiment, the feed mixture comprises a slag-forming agent and / or this is added to the process in steps i) and / or iii). In this connection, it is particularly preferably envisaged that the feed mixture comprises a slag-forming agent in an amount of at least 1 / 8, more preferably at least 1 / 5 and even more preferably at least 1 / 3 of the mass proportion of the e-waste present in the feed mixture. The slag-forming agent is advantageously selected from the series comprising iron, calcium oxides, iron oxides, silicon oxides, magnesium oxides, sodium oxides, calcium carbonates, magnesium carbonates, sodium carbonates and / or calcium hydroxides, iron hydroxides, magnesium hydroxides, sodium hydroxides and / or mixtures thereof.

[0031] Advantageously, the e-waste or feed mixture preferably comprises an aluminum content (elemental) of 0.1 wt.%, more preferably an aluminum content of at least 0.5 wt.%, even more preferably an aluminum content of at least 1.0 wt.%, most preferably an aluminum content of at least 3.0 wt.%. The e-waste or feed mixture is limited with respect to the maximum content of elemental aluminum, since too high an aluminum content adversely affects the viscosity and therefore the flowability of the slag phase, and also the separation behavior between the metal phase and the slag phase. Therefore, the e-waste or feed mixture preferably comprises at most 20.0 wt.% aluminum, more preferably at most 15.0 wt.% aluminum, even more preferably at most 11.0 wt.% aluminum, most preferably at most 8.0 wt.% aluminum.

[0032] In the case where the e-waste or the feed mixture has an aluminum content of less than 5.0 wt.%, it is advantageously contemplated that the slag-forming agent is added to the process, preferably in step i), in an amount of up to 25.0 wt.%, based on the amount of e-waste contained in the feed mixture. In the case where the e-waste or the feed mixture contains a higher aluminum content, in particular an aluminum content of 5.0-10.0 wt.%, the amount of slag-forming agent added to the process, preferably in step i), is advantageously 10.0-45.0 wt.%. In the case where the e-waste or the feed mixture contains an even higher aluminum content, in particular an aluminum content of >10.0 wt.%, the amount of slag-forming agent added to the process, preferably in step i), is advantageously 20.0-60.0 wt.%.

[0033] Preferably, the feed mixture is designed such that its viscosity in the molten state, i.e., in a liquid aggregate state, is in the range of 0.01 to 10.0 Pa*s, more preferably in the range of 0.05 to 10.0 Pa*s, even more preferably in the range of 0.1 to 10.0 Pa*s, and most preferably in the range of 0.1 to 5.0 Pa*s.

[0034] The loading into the melting reactor, and therefore the energy input, may be uneven due to different particle sizes, especially oversized particle sizes, which may result in undesirable conditions during the melting process. Therefore, the e-waste is provided in shredded form, where smaller unavoidable fractions, such as dust and / or wheat-like fractions, are always included due to the shredding process.

[0035] Advantageously, the electronic waste is shredded to a particle size of less than 20.0 inches, more preferably less than 15.0 inches, even more preferably less than 12.0 inches, even more preferably less than 10.0 inches, even more preferably less than 5.0 inches, and particularly preferably less than 2.0 inches. However, it should not exceed a particle size of 0.1 inches, preferably 0.5 inches, and even more preferably 1.5 inches. In this connection, it has been found to be particularly advantageous if the electronic waste is additionally provided in the form of pressed products according to step i), whereby, on the one hand, the reactor space of the melting reactor is optimally utilized and, on the other hand, the melting process is accelerated.

[0036] The term "presses" is understood in the sense of the present invention to mean pieces compressed and shaped from shredded electronic waste. In this respect, the presses can form briquettes, pellets and / or agglomerated packages.

[0037] The present invention and the technical environment are described in more detail below based on examples. It should be noted that the present invention is not limited to the described examples. In particular, unless expressly stated otherwise, it is also possible to extract partial aspects of the described situations and combine them with other elements and findings from this specification. EXAMPLES

[0038] The method is intended in principle for the recovery of non-ferrous metals from groups 8 to 14 of the periodic table, in the present embodiment in particular for the recovery of blister copper from electronic waste, with correspondingly significant proportions of silver (Ag), gold (Au), platinum (Pt) and palladium (Pd) being obtained as well.

[0039] In the first process step, 68% by weight of electronic waste, 25% by weight of iron oxide additive and 7% by weight of SiO 2 A feed mixture was used containing slag formers and the balance in the form of additives.

[0040] The e-waste prepared consisted of pressed pieces of 1.5-2.5 inch size compressed from shredded e-waste. The composition of the e-waste was 18 wt% Cu; 25 wt% hydrocarbons; 7 wt% Al, 12 wt% Si, 7 wt% heavy metals from the series including Pb, Sn, Ni, Cr and Zn, 3 wt% Ca, 2 wt% halogens, and 5 wt% Fe, with the balance being chemically bound oxygen and unavoidable impurities.

[0041] The feed mixture was melted in a rotary melting reactor, in this example a rotary TBRC, in the presence of atmospheric oxygen. For this purpose, the mixture was ignited in the melting reactor by means of a burner and the pyrolysis reaction was started. The feed mixture had a combustion value of about 9800 kJ / kg.

[0042] The combustion reaction and therefore the heat release could be precisely controlled by the amount of oxygen added. The volumetric flow of atmospheric oxygen always prevailed in a reducing atmosphere at the surface of the melt and reduced the CO from the organic content. 2 and H 2 Complete combustion to O does not occur, and a certain content of CO and H 2 were adapted to be present in the process gas. These were combusted either at the top of the melting reactor or outside the melting reactor.

[0043] After a few minutes, at a temperature of about 1200-1300° C., a first melt was formed having a first metal phase and a first slag phase floating on the metal phase, which were then separated according to a second process step via a tap port located in the side wall of the melting reactor. The slag phase was analyzed and found to have a copper content of 0.3-2.0 wt. % and a viscosity of about 0.3 Pa*s.

[0044] The first metal phase remaining in the melting reactor, with a copper content of about 97% by weight, was refined or converted in a further process step with the aid of oxygen-containing gas. For this purpose, oxygen-enriched air was blown through a lance into the metal first phase, so that the oxygen-affinity elements present in the metal phase, such as lead (Pb), tin (Sn), nickel (Ni), iron (Fe), silicon (Si), titanium (Ti), sodium (Na), calcium (Ca), aluminum (Al), magnesium (Mg), etc., were oxidized from the metal phase. This process step can optionally be assisted by the addition of a slag-forming agent and can be thermally adjusted by the addition of copper-containing residues as cooling waste. This second slag phase formed also had a lower density compared to the metal phase. This process step of conversion was repeated twice in this example, with the surface of the resulting slag phase being extracted after each conversion step and analyzed with respect to its composition. During the last conversion step, a copper-rich slag phase was formed, which was composed of copper oxide (Cu 2 O) had a copper content of about 20% by weight.

[0045] Through a further tap port located at the bottom of the smelting reactor, the refined / converted first metal phase was discharged from the smelting reactor, while the copper-rich slag phase of the final conversion stage remained in the smelting reactor.

[0046] The process with a new batch was then started according to step i) by adding and melting a new feed mixture containing electronic waste onto the copper-rich slag phase, whereby this second feed mixture had the same composition as the first feed mixture, but this was not necessary. Due to the reducing conditions prevailing during melting, the blister copper and heavy metal contents of the slag phase could be directly recovered. In this way, remelting of the slag phase could be avoided, resulting in an energy saving of about 350 kWh per ton of slag remaining in the melting reactor. While this application is directed to the invention set forth in the claims, the disclosure of this application also includes: 1. A method for the recovery of metals of groups 8 to 14, in particular blister copper, comprising the steps of: i) providing and melting in a melting reactor a feed mixture including electronic waste to form a first melt having a first metal phase and a first slag phase; ii) removing the first slag phase from the melting reactor; iii) smelting the remaining first metal phase with an oxygen-containing gas, optionally with the addition of a copper-containing residue, to form a second copper-rich slag phase; iv) optionally removing the second slag phase and repeating step iii); v) removing the refined first metal phase from the melting reactor; and vi) adding a further feed mixture comprising electronic waste to the remaining second copper-enriched slag phase and repeating process steps i) to vi); The method comprising: 2. The method according to claim 1, wherein the first slag phase is reduced using a reducing agent. 3. The method according to claim 1 or 2, wherein the entire process is carried out at a temperature of at least 1150°C. 4. The method according to any one of 1 to 3, wherein the feed mixture comprises electronic waste in an amount of at least 10% by weight. 5. The method of any one of claims 1 to 4, wherein the feed mixture comprises a slag forming agent and / or a slag forming agent is added to the process in steps i) and / or iii). 6. The method of claim 5, wherein the feed mixture comprises a slag-forming agent in an amount of at least 1 / 8 of the mass fraction of the electronic waste present in the feed mixture. 7. The method according to claim 5 or 6, wherein the slag former is selected from the group consisting of iron (metal), calcium-, magnesium-, sodium-, silicon-, iron-oxides, -carbonates and / or -hydroxides. 8. The method according to any one of 1 to 7 above, wherein the electronic waste has an aluminum content of 0.1 to 20.0% by weight. 9. The method according to any one of 1 to 8 above, wherein the electronic waste has an organic matter content of 5.0 to 80.0% by weight. 10. The method according to any one of claims 1 to 9, wherein the electronic waste is shredded to a particle size of less than 20 inches and, optionally, provided in the form of a pressed product according to step i). 11. The method according to any one of 1. to 10. above, wherein step i) is assisted by selective blowing of an oxygen-containing gas. 12. The method according to any one of claims 1 to 11, wherein the metal phase is withdrawn through a tap port located at the bottom and / or at the side wall of the melting reactor.

Claims

1. A method for recovering blister copper, comprising the steps of: i) providing and melting in a melting reactor a feed mixture including electronic waste to form a first melt having a first metal phase and a first slag phase; ii) removing the first slag phase from the melting reactor; iii) smelting the remaining first metal phase with an oxygen-containing gas, optionally with the addition of a copper-containing residue, to form a second copper-rich slag phase; iv) optionally removing the second slag phase and repeating step iii); v) removing the refined first metal phase from the melting reactor; and vi) adding a further feed mixture comprising electronic waste to the remaining second copper-enriched slag phase and repeating process steps i) to vi); The method comprising:

2. 2. The method of claim 1, wherein the first slag phase is reduced with a reducing agent.

3. 3. The method according to claim 1 or 2, wherein the entire process is carried out at a temperature of at least 1150°C.

4. The method according to any one of claims 1 to 3, wherein the feed mixture comprises electronic waste in an amount of at least 10% by weight.

5. The method according to any one of claims 1 to 4, wherein the feed mixture comprises a slag forming agent and / or a slag forming agent is added to the process in steps i) and / or iii).

6. 6. The method of claim 5, wherein the feed mixture comprises a slag-forming agent in an amount of at least 1 / 8 of the mass fraction of the electronic waste present in the feed mixture.

7. 7. The method according to claim 5 or 6, wherein the slag formers are selected from the series comprising iron (metal), calcium-, magnesium-, sodium-, silicon-, iron-oxides, -carbonates and / or -hydroxides.

8. The method according to any one of claims 1 to 7, wherein the electronic waste has an aluminium content of 0.1 to 20.0% by weight.

9. The method according to any one of claims 1 to 8, wherein the electronic waste has an organic content of 5.0 to 80.0% by weight.

10. The method according to any one of claims 1 to 9, wherein the electronic waste is shredded to a particle size of less than 20 inches and, optionally, provided according to step i) in the form of a pressed product.

11. The method according to any one of claims 1 to 10, wherein step i) is assisted by selective bubbling of an oxygen-containing gas.

12. The process according to any one of the preceding claims, wherein the metallic phase is withdrawn through a tap port arranged in the bottom and / or in the side wall of the melting reactor.