JPH06299262A - Treatment of molten metal of te-containing copper - Google Patents

Abstract

PURPOSE:To suppress erosion of lining refractories satisfying requirements and to obtain a high Te removal rate by using such refractories at the time of removing Te from molten metal of a Te-contg. copper system by using Na2CO3 and/or K2CO3 as a refining agent. CONSTITUTION:The Al2O3 refractory material which contains >=5wt.% SiC and is limited in SiO2 content to <=2wt.% is used as the lining material for a molten metal treatment furnace at the time of adding the Na2CO3 and/or K2CO3 as the refining agent to the molten metal of the copper system contg. the Te and slagging off and removing the Te as the composite compd. thereof. As a result, the erosion of the refractories is prevented and an excellent Te removing effect is assured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a Te-containing copper-based metal which is devised so that Te can be efficiently removed from a molten copper-based metal containing Te as an impurity while preventing melting damage of a refractory lining in a processing furnace. The present invention relates to a method for treating molten metal.

[0002]

2. Description of the Related Art Copper and copper alloys have excellent heat conductivity and conductivity as well as excellent corrosion resistance and workability. It is widely used in various fields.
However, since copper has less reserves of raw material ore than steel materials and is expensive, recovery and reuse of scrap has become an important issue from the viewpoint of resource conservation.

However, as the application fields of copper or copper alloys are expanded and various functional improvements are added depending on the applications as mentioned above, impurities contained in scraps recovered as scrap copper and the like are also diversified. However, various impurities, which are not mixed in the conventional example, are mixed, which adversely affects the physical properties of the recovered recycled product.

Of these impurity elements, Te has a lower melting point than copper, so if it remains as an impurity in a recovered product of copper or a copper alloy, it segregates at the grain boundaries and causes work cracks and surface defects. Therefore, it is necessary to remove as much as possible at the melting stage. Therefore, research is also progressing on a method of removing Te in the melting stage, and one of them is to add Na ₂ Co ₃ in the melting stage to remove Te in the molten copper-based metal from N
A method has been proposed in which a ₂ CO _{3 is used} to capture and slag to float and separate.

[0005]

However, although the above-mentioned method seems to be an effective method in a laboratory, it is applied to Te removal in a melting stage of a practical scale using a reverberatory furnace or an induction furnace. It turned out that Te could not be removed at all and that the refractory lining in the smelting furnace was significantly damaged. The present invention has been made in view of such circumstances, and an object thereof is to efficiently remove Te from a Te-containing copper-based metal molten metal while suppressing melting loss of a refractory lining refractory material. It aims to establish a technology that can do it.

[0006]

Means for Solving the Problems The configuration of the melt processing method according to the present invention that has solved the above problems, Na as refining agent in the copper-based metal melt containing Te ₂ CO ₃ and / or K ₂ CO _In adding ₃ to remove Te as a complex compound thereof, Al ₂ O containing 5 wt% or more of SiC and having a SiO ₂ content of 2 wt% or less was used as a lining material for the molten metal treatment furnace. _The point is to use ₃ series refractory materials. In carrying out this method, a reverberatory furnace or an induction furnace is used as a processing furnace, and the O ₂ concentration in the Te-containing copper-based metal melt is increased to 1000 ppm or more, whereby Te can be removed more efficiently. .

[0007]

[Function] As described above, the present inventors
Although it is possible to remove e, Te cannot be removed in the actual production scale smelting stage using a reverberatory furnace or an induction furnace, and if Na ₂ Co ₃ is added as a refining agent in the smelting stage, it is lined. From the confirmation result that the refractory is significantly melted,
Na ₂ CO ₃ added for Te removal causes some reaction with the refractory lining components, and this reaction not only melts the refractory but also deteriorates Na ₂ CO ₃ and does not lose the Te removal effect. I thought.

That is, Al ₂ O is used as a refractory lining for a reverberatory furnace or an induction furnace which is usually used for refining a molten copper metal.
A composite oxide mainly composed of ₃ and containing 10 to 40% of SiO ₂ is used. Therefore, it is considered that a part of these refractory components reacts with Na ₂ CO ₃ to be melted and damaged, and adversely affects Te removal.

Therefore, using experimental crucibles having various Al ₂ O ₃ / SiO ₂ ratios, Na ₂ CO ₃ was added to a pure copper metal melt (1200 ° C.) containing about 100 ppm Te in an amount of 1% based on the weight of the melt. Te when Te is added to remove Te
The removal rate was investigated. As a result, as shown in Table 1 below, as the SiO ₂ content in the crucible refractory increases, the Te removal rate decreases remarkably, and especially when the SiO ₂ content is 15% or more,
It has been found that Te cannot be removed at all when using a crucible made of l ₂ O ₃ / SiO ₂ based refractory.

[0010]

[Table 1]

As is clear from Table 1, Na ₂ CO
_In order to sufficiently increase the Te removal rate by ₃ , it is necessary to use an Al ₂ O ₃ / SiO ₂ refractory having a SiO ₂ content of 10% or less. However, it was confirmed that even if the SiO ₂ content was 10% or less, the melting loss of the crucible proceeded considerably.

Therefore, in order to improve the corrosion resistance, an attempt was made to combine the molten copper-based metal with SiC which has the effect of improving the corrosion resistance of both Na ₂ CO ₃ . That is, an experimental apparatus as shown in FIG. 1 (in the figure, 1 is a graphite crucible, 2 is a test refractory piece: 5
0 mm × 200 mm × 30 mm), and when the melting process was performed by adding 1% of Na ₂ CO ₃ to the weight of the molten copper-based metal at 1200 ° C.
The 1 ₂ O ₃ / SiC-based refractory material was immersed in the molten metal as the test refractory material 2 and the melting states of the test refractory material 2 were compared.

The results are shown in Table 2, and Al ₂ O ₃
5% or more, more preferably 5 to 10% of SiC
It can be seen that the Al ₂ O ₃ / SiC-based refractory material in which the above-mentioned compounds are combined has an excellent effect on the melting resistance.

[0014]

[Table 2]

Further, Table 3 shows Al ₂ O ₃ / SiC / SiO ₂ refractories in which the SiC content is set to 2 to 10% and 0%, 2% and 5% of SiO ₂ is compounded. The results of examination of the melting resistance are shown in the same manner as above.

[0016]

[Table 3]

As is clear from Table 3, Al ₂ O ₃
Be those of equivalent amounts of SiC conjugated to be, SiO ₂
When the content exceeds 2%, the melting resistance is obviously deteriorated. Then, by combining the results of Table 3 and Tables 1 and 2 above, the preferable lining refractory composition when Te 2 is removed by adding Na ₂ CO ₃ to the Te-containing copper-based metal melt is 5
% Or more, more preferably 5 to 10% of SiC, and it can be confirmed that it is an Al ₂ O ₃ -based refractory having a SiO ₂ content of 2% or less.

Table 4 below shows Al ₂ O ₃ -6% SiC.
When using a smelting furnace lined with a refractory having a composition of -1% SiO ₂ , 1% Na ₂ CO ₃ was added to a pure copper metal melt having a Te content of 100 ppm, and Te removal treatment was performed at about 1200 ° C. shows the results for the case where the O ₂ concentration in the melt with various changes of the over fire air amount was varied in the range of 10 to 10,000 ppm, which was examined O ₂ concentration and the Te removal of relationship in the melt .

[0019]

[Table 4]

As is clear from this result, Na ₂
When Te is removed using CO ₃ , as described above, N
It is important to prevent the reaction between a ₂ CO ₃ and the refractory component, but in addition to that, the O ₂ concentration in the molten metal should be 1000 p
It can be seen that it should be increased above pm, more preferably above 2000 ppm.

In the above description, the case of Te removal using Na ₂ CO ₃ has been described.
It has been confirmed that almost the same results are obtained when K ₂ CO ₃ is used instead of a ₂ CO ₃ . Also this Te
The removal treatment is preferably performed in an oxidizing atmosphere as described above. Therefore, a reverberatory furnace or an induction furnace is used as a melting furnace, and Al ₂ O ₃ —SiC (5% or more) —SiO ₂ (2
% Or less) is preferably lined with a refractory material satisfying the component composition.

[0022]

EXAMPLES Next, the constitution and operational effects of the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, and conforms to the spirit of the preceding and the following. It is also possible to carry out the invention by changing it within the range to be obtained, and all of them are included in the technical scope of the present invention.

Example 1 Te removal treatment from a Te-containing pure copper-based scrap molten metal was carried out under the following conditions to examine the Te removal rate and the melting state of the refractory lining. Melting furnace: 20 tons heavy oil fired reverberatory furnace Refractory lining: Al ₂ O ₃ (93%) / SiC (6%) /
SiO ₂ (1%) Melting raw material: Electric wire scrap using tough pitch copper (Cu
-0.010% Te) Melting conditions: temperature (1200 ° C), atmospheric melting (O ₂ concentration in molten metal: 6000 ppm), Na ₂ CO ₃ (2% added to molten metal weight) As a result, Te content in molten metal is 100 ppm From 50p
pm, and almost no melting loss of the refractory lining was observed. Example 2 Te was removed from the Te-containing copper alloy scrap molten metal under the following conditions, and the Te removal rate and the melting state of the lining refractory were examined.

Smelting furnace: 5-ton heavy oil-fired reverberatory furnace Refractory lining: Al ₂ O ₃ (92%) / SiC (7%) /
SiO ₂ (2%) Melting raw material: Cu-Ni alloy scrap (Cu-1% Ni-0.01)
2% Te) Melting conditions: temperature (1250 ° C.), atmospheric melting (O ₂ concentration in molten metal: 5000 ppm), Na ₂ CO ₃ (2% addition to molten metal weight) As a result, Te content in molten metal is 120 ppm 55p
pm, and almost no melting loss of the refractory lining was observed.

[0025]

The present invention is configured as described above,
When Te _{2 is} removed by adding Na ₂ CO ₃ and / or K ₂ CO ₃ as a refining agent to a Te-containing molten copper metal, it contains an appropriate amount of SiC as a refractory lining for a melting furnace and contains Si.
By using refractory materials with a limited O ₂ content,
It has become possible to secure an excellent Te removal effect while preventing melting damage of the refractory lining material.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an apparatus used in a melting experiment.

[Explanation of symbols]

 1 Crucible 2 Test refractory piece

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Motohiro Arai 1-5-5 Takatsukadai, Nishi-ku, Kobe-shi, Hyogo Prefecture Kobe Steel Institute of Technology, Kobe Steel Co., Ltd. No. 14-1 Kobe Steel Works, Ltd. Chofu Factory (72) Inventor Eiji Yoshida Chofu Minato-cho, Shimonoseki City, Yamaguchi Prefecture 14-1 Kobe Steel Works Ltd. Chofu Factory (72) Inventor, Hirofumi Okada No. 14-1 Kobe Steel Works, Ltd. Chofu Works (72) Inventor Ryusuke Hamanaka 14-1 Chofu Minatomachi, Shimonoseki City, Yamaguchi Prefecture Kobe Steel Works Chofu Works

Claims (3)

[Claims] 1. Na ₂ CO ₃ and / or K ₂ CO ₃ as a refining agent is added to a copper-based metal melt containing Te,
When slagging and removing Te as these complex compounds, 5 wt% or more of Si is used as a lining material for the molten metal treatment furnace.
A method for treating a Te-containing copper-based metal melt, comprising using an Al ₂ O ₃ -based refractory material containing C and having a SiO ₂ content limited to 2% by weight or less. 2. Te as Na ₂ CO ₃ and / or K ₂
The treatment method according to claim 1, wherein the concentration of O ₂ in the molten copper-based metal is increased to 1000 ppm or more when the slag is removed and removed as a complex compound with CO ₃ . 3. The processing method according to claim 1, wherein a reverberation furnace or an induction furnace is used as the molten metal processing furnace.