KR20160066804A - Method for Removing Pb from Cupper Alloy Waste Using Ca Cored Wire - Google Patents

Abstract

The present invention relates to a method to remove lead from copper alloy scrap using a calcium wire. The method comprises: a step of dissolving copper alloy scrap; a step of adding a calcium wire to the resultant solution of dissolving copper alloy waste, and dissolving the calcium wire; and a step of elevating the temperature of the resultant product. The method may additionally comprises a step of adding a reaction catalyst, which is able to remove lead from copper alloy scrap with a high removal rate.

Description

[0001] The present invention relates to a method for removing lead from a copper alloy scrap using calcium wire,

The present invention relates to a method for removing lead from copper alloy scrap, and more particularly to a method for removing lead from copper alloy waste using calcium wire.

Generally, copper alloys are excellent in heat and electric conductivity and are widely used as materials for heat exchangers and electric / electronic parts due to good processability It is coming. In view of resource saving and energy saving, copper alloys having such excellent characteristics are recovered and recycled from copper alloy scraps generated during processing or from spent copper alloys after use.

However, since these copper alloy scraps or the discarded copper alloy are mixed with different materials, plating, insulating materials and the like, they are selected for reuse.

On the other hand, a copper alloy containing lead and a copper alloy containing no lead are present in the copper alloy scrap or the discarded copper alloy. Therefore, in order to use them, it is necessary to remove lead before reuse so that lead is not incorporated.

However, when a large amount of copper alloy scrap is mixed with a lead-containing copper alloy, it is difficult to discriminate the copper alloy. It is also possible to consider a method in which lead is oxidized after dissolution and is flotated and removed as lead oxide. However, in this oxidation method, zinc is also oxidized and removed, which makes it difficult to remove only lead.

International Patent Application Publication No. 10-1993-7003474, entitled " Mechanically shaped copper alloy with reduced lead content, published on November 30, 1993}

Accordingly, an object of the present invention is to provide a method for removing lead from copper alloy waste.

In order to solve the above problems,

Dissolving the copper alloy waste to form a copper alloy melt;

Adding a calcium wire to a copper alloy melt to dissolve the copper alloy melt; And

And heating the molten metal to remove lead from the copper alloy waste using the calcium wire.

In the lead removal method according to the present invention, the copper alloy waste may be a copper alloy scrap or a discarded copper alloy.

In the lead removal method according to the present invention, the step of dissolving the copper alloy waste and the step of adding and dissolving the calcium wire are all preferably performed at a temperature of 900 to 950 ° C, Is preferably contained in a range of 0.5 to 3.0 wt% based on the weight of the composition,

In the lead removal method according to the present invention, it is more preferable to further include a reaction promoter in the melt dissolved in the copper alloy waste.

The reaction promoter may be added after the calcium wire addition, after the calcium wire addition, or before and after the calcium wire addition.

 The step of adding and dissolving the reaction promoter is preferably carried out by stirring at a temperature of 900 to 950 캜 for 5 to 10 minutes.

As the reaction promoter according to the present invention, NaF is preferably used and is preferably contained in the range of 0.5 to 3 wt% based on the weight of the copper alloy waste.

By using the calcium wire according to the present invention, the lead removal efficiency can be improved from the copper alloy waste, and the lead removal efficiency can be further improved when the calcium wire and the reaction additive are used at the same time.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a photograph showing a microstructure of a sample according to a treatment method for a copper alloy scrap. FIG.
Fig. 2 is a photograph showing the microstructure of the sample according to the processing temperature of the copper alloy scrap. Fig.
3 is a photograph showing the microstructure of the sample according to the amount of the treatment reagent (calcium wire) used for the copper alloy scrap.
4 is a SEM photograph of a Ca, Ca-Pb compound formed on a sample when a calcium alloy wire is used as a copper alloy scrap.

Hereinafter, the present invention will be described in more detail.

A method for removing lead from copper alloy waste using calcium wire according to the present invention includes dissolving copper alloy waste to form a copper alloy melt; Adding a calcium wire to a copper alloy melt to dissolve the copper alloy melt; And raising the temperature of the melt.

In the step of dissolving the copper alloy waste to form a copper alloy melt, the copper alloy waste may be a copper alloy scrap or a discarded copper alloy.

The dissolution of the copper alloy waste is preferably performed at a temperature of 900 to 950 캜, more preferably 900 to 930 캜. The brass starts to solidify at a temperature lower than 900 DEG C, which is not preferable because it is not easy to handle, and the lead removal rate can be optimized within the above range.

In addition, in the step of adding and dissolving the calcium wire to the copper alloy melt, the calcium wire means a Ca cored wire and refers to a wire in which the calcium powder is coated with copper or other metal. Preferably, the calcium wire is a calcium wire coated with a copper thin plate in an amount of 1 to 30 wt% of Ca, and the calcium wire is preferably added in a range of 0.5 to 3 wt% based on the total weight of the copper alloy waste, more preferably 1.0 To 2.0% by weight. If it is added in an amount of less than 0.5% by weight, it may have little influence on the lead removal rate. If it is added in an amount exceeding 3% by weight, an economical lead removal effect can not be obtained.

The dissolution temperature of the calcium wire is preferably 900 to 950 캜, and more preferably 900 to 930 캜. It is also preferable to carry out stirring for 5 to 10 minutes.

With the addition of the calcium wire, calcium and lead form slag, and by removing it, the lead removal rate can be increased.

In this case, the temperature is preferably raised to a temperature of 1000 ° C or higher, and specifically, it is preferable to raise the temperature to 950 ° C to 1,050 ° C.

A reaction promoter may be further added together with the calcium wire, and the lead removal efficiency may be further increased by adding a reaction promoter.

The reaction promoter may be added after the calcium wire addition, after the calcium wire addition, or before and after the calcium wire addition.

The step of adding and dissolving the reaction promoter is preferably carried out by stirring at a temperature of 900 to 950 ° C, more preferably 900 to 930 ° C for 5 to 10 minutes.

As the reaction promoter according to the present invention, NaF is preferably used and is preferably contained in the range of 0.5 to 3 wt% based on the weight of the copper alloy waste. When the reaction accelerator is added dividedly before and after the calcium wire addition, it can be added in a weight ratio of 1: 1.

Hereinafter, the present invention will be described concretely with reference to Examples, but the present invention is not limited by the following Examples.

Example  One

4000 kg of a copper alloy strap containing 3% by weight of Pb was put into a crucible type melting furnace, and melted at a temperature of 930 캜 until it was melted. Subsequently, 60 kg of calcium wire (Ca 1.5 wt%) was added and dissolved by stirring for 10 minutes while maintaining the temperature at 930 캜. The lead-calcium slag was then removed. The melt was heated to a temperature of 1000 캜 and then allowed to boil.

Example  2

4000 kg of a copper alloy strap containing 3% by weight of Pb was put into a crucible type melting furnace and dissolved at a temperature of 930 캜. Subsequently, 20 kg of NaF was added as a reaction promoter, and the mixture was stirred and dissolved for 5 minutes while maintaining the temperature at 930 ° C. Subsequently, 60 kg of calcium wire (Ca 1.5 wt%) was added and dissolved by stirring for 10 minutes while maintaining the temperature at 930 캜. The slag was then removed. Subsequently, 20 kg of NaF was added as a reaction promoter, and the mixture was stirred and dissolved for 5 minutes while maintaining the temperature at 930 ° C. The slag was then removed. The melt was heated to a temperature of 1000 캜 and then allowed to boil.

Example  3

4000 kg of a copper alloy strap containing 3% by weight of Pb was put into a crucible type melting furnace and dissolved at a temperature of 930 캜. Subsequently, 40 kg of NaF was added as a reaction promoter, and the mixture was stirred and dissolved for 10 minutes while maintaining the temperature at 930 ° C. Subsequently, 60 kg of calcium wire (Ca 1.5 wt%) was added and dissolved by stirring for 10 minutes while maintaining the temperature at 930 캜. The slag was then removed. The melt was heated to a temperature of 1000 ° C and then allowed to boil.

Example  4

4000 kg of a copper alloy strap containing 3% by weight of Pb was put into a crucible type melting furnace and dissolved at a temperature of 930 캜. Subsequently, 60 kg of calcium wire (Ca 1.5 wt%) was added and dissolved by stirring for 10 minutes while maintaining the temperature at 930 캜. The slag was then removed. Subsequently, 40 kg of NaF was added as a reaction promoter, and the mixture was stirred and dissolved for 10 minutes while maintaining the temperature at 930 캜. The slag was then removed. The melt was heated to a temperature of 1000 ° C and then allowed to boil.

Test Example  One

In Examples 1 to 4, the Pb content of the copper alloy strap before the treatment and the copper alloy strap after the treatment were examined by a SES (Spark Emission Spectrometer) method. The results are shown in Table 1 below. Fig. 1 is a photograph of the microstructure of the sample taken with a metallurgical microscope.

Example Processing method Removal rate (Pb content change) One Calcium wire 50% (3.36 → 1.68) 2 1 / 2NaF + calcium wire + 1 / 2NaF 70% (2.94 → 0.88) 3 NaF + calcium wire 51% (2.94 → 1.43) 4 Calcium wire + NaF 82% (3.36? 0.62)

From Table 1, it was found that the use of the calcium wire alone and the NaF, which is a reaction promoter, was more effective in terms of the removal rate of Pb than the calcium wire alone. Addition of NaF before and after the addition of calcium wire resulted in higher removal rate, The highest removal rate was obtained when NaF was added after wire addition. 1, when NaF was added after addition of calcium wire, it was confirmed that Pb reacted with Ca to form a much larger portion of Ca-Pb compound.

Test Example  2

The copper alloy scrap was treated in the same manner as in Example 2, except that the treatment temperature was changed to 900 ° C., 930 ° C., 950 ° C., and 980 ° C., and the respective Pb removal rates were examined. And the microstructure of the sample according to the treatment temperature is shown in Fig.

Example 2 Treatment temperature Removal rate (Pb content change) 900 ℃ 82% (2.63 → 0.48) 930 ° C 70% (2.94 → 0.88) 950 ℃ 42% (2.89 → 1.68) 980 ° C 44% (2.77 - > 1.56)

From Table 2, it can be seen that although the highest removal rate was observed at 900 ° C., the coagulation of brass started at 900 ° C., and the lower temperature was not preferable, and the removal rate from 950 ° C. was remarkably decreased. 2, it can be confirmed that at a treatment temperature of 900 ° C, Pb reacts with Ca to form a much larger portion of the Ca-Pb compound.

Test Example  3

The copper alloy scrap was treated in the same manner as in Example 2 except that the content of calcium wire was changed to 0.5 wt%, 1 wt%, 1.5 wt%, and 3 wt% The results are shown in Table 3, and the microstructure of the sample according to the calcium wire content is shown in FIG.

Example 2 Calcium wire content Removal rate (Pb content change) 0.5 wt% (20 kg) 24% (2.90 - 2.20) 1.0 wt% (40 kg) 63% (3.15 - 1.18) 1.5 wt% (60 kg) 70% (2.94 → 0.88) 3.0 wt% (120 kg) 75% (3.10 → 0.76)

From Table 3, it can be seen that the removal rate is high in the range of 1.0 wt% to 3.0 wt% based on the total weight of the copper alloy scrap, while the removal rate is remarkably lower in the case of 0.5 wt%. 3, it was confirmed that at a Ca content of 3.0% by weight, Pb reacted with Ca to form a much larger portion of the Ca-Pb compound.

Test Example 4

The copper alloy scrap was processed in the same manner as in Example 2, except that the calcium wire content was changed to 1.5 wt% and 3 wt%, respectively, and the samples were photographed by SEM to observe Ca and Ca-Pb compounds The results are shown in Fig.

According to Fig. 4, Ca and Ca-Pb compounds were observed in the matrix of? Phase, and the portion observed in white in the compound was judged to be a Ca-Pb compound. The Ca compound is judged to be a compound of the Cu (x) -Ca (y) series, and the Ca-Pb compound is judged to be a Ca (x) -Pb (y) series. Pb reacts with the Ca compound to be removed by slag, and Pb which is not slagged is judged to remain in the brass base.

In conclusion, the lead removal technique according to the present invention can be confirmed to be influenced by 1) the dissolution temperature, 2) the amount of calcium wire added, and 3) the method of adding calcium wire and reaction accelerator (NaF). That is, the lower the dissolution temperature, the higher the lead removal rate, the better at 900 to 930 ° C, the more difficult to handle due to the start of coagulation of brass at 900 ° C, In addition, the removal rate of the calcium wire was 1.0 to 3.0 wt%, and the lead removal effect was 1.5 wt%. In addition, the addition of a reaction accelerator after adding calcium wire showed the best lead removal rate.

Claims (8)

Dissolving the copper alloy waste;
Adding a calcium wire to a copper alloy waste melt and dissolving the same; And
And heating the melt to remove lead from the copper alloy waste using the calcium wire.
The method according to claim 1,
Wherein the copper alloy waste is a copper alloy scrap or a discarded copper alloy.
The method according to claim 1,
Wherein the step of dissolving the copper alloy waste and the step of adding and dissolving the calcium wire are all performed at a temperature of 900 to 950 캜.
The method according to claim 1,
Wherein the calcium wire is included in the range of 0.5 to 3.0 wt% based on the weight of the copper alloy waste.
The method according to claim 1,
Further comprising a reaction additive in the melt dissolved in the copper alloy waste.
6. The method of claim 5,
Wherein the reaction additive is added after the calcium wire addition, after the calcium wire addition, or before and after the calcium wire addition.
6. The method of claim 5,
Wherein the step of adding and dissolving the reaction additive is carried out by stirring at a temperature of 900 to 950 DEG C for 5 to 10 minutes.
6. The method of claim 5,
Wherein the reaction additive is NaF and is contained in the range of 0.5 to 3 wt% based on the weight of the copper alloy waste.

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