Method for the recovery of metals from electronic waste

Abstract

A method for obtaining metals of the 8th to 14th groups, in particular raw copper, comprises the following steps: i) providing and melting down a mixed feed comprising electronic waste in a smelting reactor, so that a first melt with a first metallic phase and a first slag phase is formed; ii) separating out the first slag phase from the smelting reactor; iii) refining the remaining first metallic phase by means of an oxygen-containing gas, possibly with the addition of copper-containing residual materials, so that a second, copper-enriched slag phase is formed; iv) possibly separating off the second slag phase and repeating the step; v) separating off the refined first metallic phase from the smelting reactor; and vi) adding a further mixed feed comprising electronic waste to the remaining second, copper-enriched slag phase and repeating process steps i) to vi).

Claims

1.-12. (canceled)

13. A method for obtaining metals of the 8th to 14th groups, in particular raw copper, comprising the steps of: i) providing and melting down a mixed feed comprising electronic waste in a smelting reactor, so that a first melt with a first metallic phase and a first slag phase is formed; ii) separating out the first slag phase from the smelting reactor; iii) refining a remaining first metallic phase by an oxygen-containing gas, possibly with an addition of copper-containing residual materials, so that a second, copper-enriched slag phase is formed; iv) possibly separating off the second slag phase and repeating step iii); v) separating off the refined first metallic phase from the smelting reactor; and vi) adding a further mixed feed comprising electronic waste to the remaining second, copper-enriched slag phase and repeating process steps i) to vi).

14. The method according to claim 13, wherein the first slag phase is reduced by a reducing agent.

15. The method according to claim 13, wherein steps i) to vi) are carried out at a temperature of at least 1150° C.

16. The method according to claim 13, wherein the mixed feed comprises the electronic waste in an amount of at least 10 wt %.

17. The method according to claim 13, wherein the mixed feed comprises a slag-forming agent and/or wherein a slag-forming agent is added to the process in steps i) and/or iii).

18. The method according to claim 17, wherein the mixed feed comprises the slag-forming agent in an amount of at least ⅛ of the mass fraction of the electronic waste present in the mixed feed.

19. The method according to claim 17, wherein the slag-forming agent is selected from the group consisting of iron, iron oxides, calcium oxide, calcium carbonate, calcium hydroxide, magnesium oxide, magnesium carbonate, magnesium hydroxide, sodium oxide, sodium carbonate, sodium hydroxide, silicon dioxide, silicon carbonate, and silicon hydroxide.

20. The method according to claim 13, wherein the electronic waste comprises an aluminum content of 0.1 to 20.0 wt %.

21. The method according to claim 13, wherein the electronic waste comprises an organic content of 5.0 to 80.0 wt %.

22. The method according to claim 13, wherein the electronic waste is crushed to a particle size smaller than 20 inches, and optionally provided in the form of pressed articles in accordance with step i).

23. The method according claim 13, wherein step i) is assisted by selectively injecting an oxygen-containing gas.

24. The method according to claim 13, wherein the metallic phase is removed via a tapping opening arranged in a bottom and/or in a side wall of the smelting reactor.

Description

DETAILED DESCRIPTION/EXAMPLE

[0042] In principle, the method is provided for obtaining non-ferrous metals of the 8th to 14th group of the periodic table. In particular, in the present design variant, it is provided for the obtaining of raw copper from electronic waste, also obtaining significant fractions of silver (Ag), gold (Au), platinum (Pt) and palladium (Pd).

[0043] In a first process step, a mixed feed comprising 68 wt % of electronic waste and residual slag-forming agents in the form of 25 wt % of an iron oxide additive and 7 wt % of an SiO.sub.2 additive was initially prepared.

[0044] The electronic waste provided consisted of pressed articles with a size of 1.5 to 2.5 inches, which were pressed from crushed electronic waste. The composition of the electronic waste was 18 wt % Cu; 25 wt % hydrocarbons; 7 wt % Al, 12 wt % Si, 7 wt % heavy metals from the series comprising Pb, Sn, Ni, Cr along with Zn, 3 wt % Ca, 2 wt % halogens and 5 wt % Fe, along with residues of chemically bound oxygen along with unavoidable impurities.

[0045] The mixed feed was melted down in the presence of atmospheric oxygen in a rotating smelting reactor, in the present case a rotating TBRC. For this purpose, the mixture in the smelting reactor was ignited by means of a burner and the pyrolytic reaction was started. The mixed feed had a calorific value of approximately 9800 kJ/kg.

[0046] The combustion reaction and thus the heat development could be specifically controlled by the amount of oxygen added. The volume flow of atmospheric oxygen was adjusted in such a manner that a reducing atmosphere always prevailed at the surface of the melt and a complete combustion of the organic fraction to CO2 and H2O did not take place; rather, specific contents of CO and H2 were present in the process gas. These were burned either in the upper part of the smelting reactor or outside the smelting reactor.

[0047] After a few minutes, at a temperature of approximately 1200-1300° C., a first melt with a first metallic phase and a first slag phase floating on the metallic phase was formed. This was then separated via a tapping opening arranged in the side wall of the smelting reactor in accordance with the second process step. The slag phase was analyzed and showed a copper content of 0.3-2.0 wt % and a viscosity of approximately 0.3 Pa*s.

[0048] The first metallic phase remaining in the smelting reactor, which had a copper content of approximately 97 wt %, was refined or converted, as the case may be, in the further process step by means of an oxygen-containing gas. For this purpose, oxygen-enriched air was injected into the metallic first phase via a lance, so that the oxygen affinity elements present in the metallic 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 metallic phase. If necessary, the process step can be assisted by the addition of slag-forming agents and thermally controlled by the addition of copper-containing residual materials as cooling scrap. This second slag phase formed also had a smaller density compared to the metallic phase. The process step of conversion was repeated twice, wherein the slag phase formed was superficially stripped off after each conversion step and analyzed with regard to composition. During the final conversion stage, a copper-enriched slag phase was formed, which had a copper content in the form of copper oxide (Cu.sub.2O) of approximately 20 wt %.

[0049] Through another tap opening located in the bottom of the smelting reactor, the refined/converted first metallic phase was discharged from the smelting reactor, while the copper-enriched slag phase of the final conversion stage remained in the smelting reactor.

[0050] Then the process started with a new batch in accordance with step i) by adding a new mixed feed comprising the electronic waste to the copper-enriched slag phase and melting it down. The second mixed feed had the same composition as the first, although this is not absolutely necessary. The reducing conditions prevailing during melting down allowed the raw copper and heavy metal content of the slag phase to be recovered directly. Since re-smelting of the slag phase can be avoided in this manner, it was possible to save approximately 350 kWh of energy pert of slag remaining in the smelting reactor.