JP3473025B2 - Purification method of copper or copper alloy raw material - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying copper or a copper alloy from a copper raw material containing copper or a copper alloy, and more particularly, to a method for refining Pb, Ni, Sb, S. , Bi, and As, and a method for efficiently removing and purifying copper or copper alloy raw materials containing impurities as at least one of Fe, Sn, and Zn as impurities. [0002] Generally, copper has excellent heat conductivity and electric conductivity, and is widely used in large quantities, including heat exchangers and materials for electric / electronic parts. Since copper has a smaller reserve than iron and the like and is more expensive, from the viewpoint of effective use of resources, used copper or copper alloy scrap or copper or copper alloy scrap generated after processing (hereinafter, referred to as “herein in this specification”) Is simply collected and reused. However, copper scrap contains dissimilar metal materials, solder,
Since a large amount of impure components such as plating and insulators are mixed, the components are ineligible as they are and their use is significantly restricted. Therefore, as a countermeasure for reducing impurities mixed into the copper chips, the copper chips are manually sorted before melting, and then the impurities are removed by performing magnetic separation or the like. However, since this method is dependent on human labor, there is a limitation on the sorting ability and the processing amount, and the like, and further, an impurity component (for example, Pb, Ni, Sb, Pb, Ni, Sb, S, Bi, As or F
e, Sn, Zn, etc.) cannot be removed. For this reason, there has been proposed a dissolving and refining method in which copper scrap is once dissolved and then oxidized or reduced, or a slagging material is added to remove slag of impurity metal components and the like (for example, JP-A-51-133125, JP-B-54).
No.-12409, JP-B-56-43094, JP-A-58-27939, 59
-211541, 59-226131, 61-217538, etc.). [0004] Among them, a method which is considered to be relatively effective is the method disclosed in Japanese Patent Application Laid-Open No. 61-217538.
According to this method, a small amount of phosphorus is added to a copper chip after melting, and an oxidizing treatment is performed to float and separate the impurity metal component together with a part of the phosphorous oxide, and then the molten metal is kept in a highly oxidized state. After oxidizing and removing residual phosphorus, oxygen is removed by a reduction treatment. However, with this method,
Among the impurity elements, Fe, Sn, Zn and the like can be removed relatively efficiently, but Pb, Ni, Sb, S, Bi or A
s is difficult to remove, and there is a problem that a considerable amount of P is mixed into the purified copper. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a raw material containing copper or copper alloy scrap or a refining process called a blister. In dissolving and refining the previous copper raw material, one or more of Pb, Ni, Sb, S, Bi and As contained in the copper raw material and one or more of Sn, Fe and Zn are efficiently separated and removed. It is an object of the present invention to provide a purification method capable of recovering high-quality copper in a high yield. [0006] The structure of the refining method according to the present invention consists of a copper containing at least one of Sn, Fe and Zn together with at least one of Pb, Ni, Sb, S, Bi and As. Alternatively, in refining the copper alloy raw material, Step 1: dissolving the copper or copper alloy raw material, Step 2a: oxidizing Sn, Fe, Zn in the molten metal by increasing the oxygen concentration in the molten metal to form a slag. Step 2b: adding at least one selected from the group consisting of Fe, Fe oxide, Mn, and Mn oxide to the molten metal, and converting Pb, Ni, Sb, S, Bi, As in the molten metal to Fe and And / or a step of forming a slag as a composite oxide of Mn, Step 3: heating the generated slag to 1225 to 1400 ° C,
The gist is that the step of removing the copper oxide in the slag as copper into the molten metal and then removing the slag, the step 4: the step of reducing the molten metal, is sequentially performed. [0008] When copper scraps and the like are used as a melting raw material,
Pb, Ni, and S are the main elements that cause component failure.
b, S, Bi, As, Fe, Zn and the like. Of these, Sn, Fe and Zn are easily oxidized by supplying a gaseous oxygen source (oxygen gas, air or the like) or a solid oxygen source (eg CuO or the like) to the raw material to be dissolved, and as a metal oxide, Since it floats on the surface, it can be easily removed. On the other hand, Pb, Ni, Sb, S, Bi, As
Cannot be easily removed only by oxidizing the dissolved raw material, and it is necessary to take other removing means. Therefore, in the present invention, as a step different from the step of oxidizing and removing Sn, Fe, and Zn, a flux consisting of one kind selected from the group consisting of Fe, Fe oxide, Mn, and Mn oxide [hereinafter, Fe ( Mn) flux.]
And a step of removing Pb, Ni, Sb, S, Bi, and As as a composite oxide of Fe and / or Mn is added. Then, oxygen is removed by reducing the molten metal in the final step to obtain copper from which impurity metal components have been removed. And these treatments include Pb, N
Fe, S together with at least one of i, Sb, S, Bi, As
When n and Zn are contained, the above steps 1 and 2
a, step 2b, step 3 and step 4 are performed in this order. Hereinafter, each step will be described in detail in order. Step 1: This step is a step of dissolving the copper raw material as the first step of the purification method according to the present invention. As copper raw materials, cutting of copper products such as copper incineration wire scraps incinerated from resin coating on the surface of electric wires, Ni-plated copper wire scraps, fin materials obtained from waste materials such as heat exchangers, plates, pipes, etc. Various copper scraps or blisters etc. such as chips generated by etc. are used,
In some cases, these may be used in combination with the remaining hot water of wrought copper or the remaining hot water that may be generated in the casting process. As a melting furnace, a known furnace such as a reflection furnace or an induction melting furnace may be used. Step 2a: In this step, a solid and / or gaseous oxygen source is supplied to the molten metal to increase the oxygen concentration, and the sulfur contained in the molten metal is increased.
In this step, n, Fe, and Zn are turned into slag as oxides.
That is, Sn, Fe, and Zn in the molten metal are easily oxidized by oxidizing the molten metal, turned into slag and float on the surface of the molten metal, and thus can be removed relatively easily. At this time, CuO or the like is used as a solid oxygen source, and oxygen or air (generally, air) is used as a gaseous oxygen source. A gas such as air is more preferable as the oxidizing agent. Oxidizing agent. In particular, Z
Since most of n tends to be oxidized after evaporating to the surface of the molten metal, it is desirable to use a gaseous oxidizing agent in order to oxidize gaseous Zn and convert it into slag. A method in which the solid oxygen source is sprayed on the surface of the molten metal;
Alternatively, either of the methods of blowing into the melt together with the carrier gas may be adopted, but the most efficient method is a method of blowing into the melt. The gaseous oxygen source is supplied by a method of blowing upward toward the surface of the molten metal or a method of blowing the molten oxygen into the molten metal, but a method of blowing the molten oxygen into the molten metal is more preferable. This oxidation step may be performed using only one of the solid oxygen source and the gaseous oxygen source, or both may be used in combination. For example, the solid oxygen source may be sprayed on the surface of the molten metal to form a gaseous oxygen source. A method in which an oxygen source is blown into the molten metal, a method in which a solid oxygen source is blown into the molten metal together with a gaseous oxygen source, and the like can be adopted. In order to efficiently remove Sn, Fe, and Zn from the molten metal in this oxidation / slagification process,
It is desired to control the supply amounts of the solid oxygen source and the gaseous oxygen source so that the oxygen concentration in the molten metal becomes 500 ppm or more. In this oxidation step, the F contained in the raw material is
e, Sn, and Zn are removed.
The slag generated in this step may be removed once before moving to the next step, or the residue may be left as it is on the surface of the molten metal and subjected to the processing in the next step, and may be removed in step 3 collectively. Step 2b: In this step, at least one selected from the group consisting of Fe, Fe oxide, Mn, and Mn oxide is added to the molten metal, and Pb, Ni, Sb, S, Bi, As is removed. That is, according to various studies conducted by the present inventors, Pb, Ni, Sb, S, Bi, and As in the molten metal are hardly oxidized as compared with the above-mentioned Fe, Sn, and Zn. Then it cannot be removed well. However, Pb, Ni, Sb, S, Bi, and As are added to the molten metal by adding at least one of Fe, Fe oxide, Mn, and Mn oxide.
As a composite oxide with e and / or Mn,
It was confirmed that the composite oxide floated on the surface of the molten metal as slag and could be easily removed. In this case, as a treatment mode when using Fe (or Mn) oxide, a method of spraying Fe (or Mn) oxide on the surface of the molten metal, and a process of spraying Fe (or Mn) oxide on the surface of the molten metal A method in which the molten metal is stirred by induction stirring or bubbling with an inert gas (Ar or the like); a part of the Fe (or Mn) oxide is sprayed on the surface of the molten metal to remove the remaining Fe (or Mn) oxide. A method of blowing the molten gas into the molten metal together with the active gas, and a method of blowing all of the Fe (or Mn) oxide into the molten metal together with the inert gas can be considered. Of the above-mentioned processing modes, Ni (or Pb,
The most preferable method for increasing the removal efficiency of Sb, S, Bi, As) is the second method, and the surprising method is not sufficient for Ni (or Pb, Sb, S, B).
An i, As) removal effect cannot be obtained, and a considerably excellent Ni (or Pb, Sb, S, Bi, As) removal effect can be obtained by the other method. However, in the above method, a part of the Fe (or Mn) oxide is changed to Fe (or Mn).
The above method is most preferable because it is dissolved in the molten metal as n) and the purpose of purification may be hindered instead. In this case, the preferable addition amount of Fe (or Mn) oxide is Ni (or Pb, Sb) in the molten metal.
b, S, Bi, As) concentration is about twice or more, and the preferred oxygen concentration at that time is Ni (or Pb, Sb).
b, S, Bi, As). The preferred amount of Fe (or Mn) oxide added in step 2b based on the weight of the molten metal is 10 to 50,000 pp per step.
m. That is, this step 2b may be performed only once when the amount of the impurity metal element to be removed is relatively small,
When the amount of the impurity metal element to be removed is large, it is preferable to repeat the process plural times. In this case, Fe,
It is desired that the amounts of Mn and their oxides be within the above ranges. The processing temperature in the above steps 1, 2a, and 2b is desirably 1200 ° C. or less. Step 3: In this step, the slag floating on the surface of the molten metal after the end of the step 2b is removed, but the amount of copper oxide taken out together with the slag at the time of slag removal is reduced as much as possible to reduce the copper footprint. In order to increase the retention, the present invention employs the following method. That is, the slag floating on the surface of the molten metal at the end of the step 2b contains a large amount of copper oxide (or oxide) of the impure metal element and the complex oxide with Fe and Mn generated in the oxidation step. Especially Cu
₂ O) are included, usually oxides or composite oxides of the impure metal elements to the copper oxide matrix component has emerged on the surface of the melt in a dispersed state. Therefore, if the slag is removed from the molten metal surface without any contrivance, a considerable amount of copper oxide is taken out together with the impurity metal component, and the Cu loss may be so large that it becomes impossible to neglect. As a means for facilitating slag removal and minimizing copper loss, prior to the slag removal after the step 2b, the slag is heated to remove copper oxide such as Cu ₂ O. A method is used in which a part of the material is returned to the molten metal as copper and then the slag is removed. The heating temperature at this time varies slightly depending on the melting point of the copper oxide, the eutectic temperature of the copper oxide and another oxide, and the like, but the heating temperature is set to 1225 so that the copper oxide can be dissolved in the molten metal. It should be in the range 1400 ° C. FIG. 1 shows that after a copper alloy containing 100 ppm of Fe, Sn, Ni, and Pb was dissolved in the air, the process was performed in step 2a.
In step 2b, 2% by weight of Fe ₂ O ₃ with respect to the weight of the molten metal is sprayed on the surface of the molten metal to perform induction stirring, and then the temperature of the molten metal is increased to 1200-200 ppm.
When the temperature is raised to 1400 ° C and the slag is removed, the temperature of the molten metal before the slag removal and the weight of the slag removed (the temperature of the molten metal is 1200
Weight ratio when the weight of debris at 100 ° C is 100)
And Fig. 6 shows the results of examining the relationship between and the impurity metal element concentration of the obtained molten metal. As is clear from this figure, when the temperature of the slag at the time of removing the slag is heated to about 1225 ° C. or more, the amount of the slag to be removed can be reduced to about 1/10, and the impurity metal oxide is removed. It can be seen that the amount of copper oxide discharged with the material can be significantly reduced. Moreover, the heating temperature is 1400 ° C. or less,
If the temperature is more surely suppressed to 1370 ° C. or lower, there is no possibility that the impurity metal element returns to the molten metal due to the temperature rise. However, when the heating temperature is 1400 ° C. or higher, particularly the Ni and Fe among the impurity metal elements tend to return to the molten metal. Therefore, the more preferable temperature at the time of removing the slag is in the range of 1300 to 1370 ° C. Further, when removing the slag, SiO ₂
If the method of adding Al ₂ O ₃ flux and removing the scum floating on the surface of the molten metal after attaching it to the flux is adopted, the scum is adsorbed by the flux and has a proper hardness. This is preferable because the slag removing efficiency can be further increased. The preferable mixing ratio of SiO ₂ and Al ₂ O ₃ in the SiO ₂ —Al ₂ O ₃ flux used here is SiO ₂ : 70 to
90% / Al ₂ O _3: 10 to 30% of the range and preferred amount of the flux is in the range of 0.005 to 0.10% relative to the molten metal by weight. This flux is composed of pure SiO ₂ and Al ₂ O ₃
In addition to those that are mixed at a predetermined ratio, CaAl ₂ SiO ₈ (Anorthite), which is naturally produced as a SiO ₂ source or Al ₂ O ₃ source, NaAlSi
₃ O ₈ (Albite), KAl ₂ (Si ₃ Al) O ₁₀ (OH, F) ₂ (Muscorite) or the like can also be used as a raw material. Step 4 (reduction step): In this step, the oxygen taken into the molten metal in the impurity metal element removing steps of the above steps 2a and 2b is removed.
That is, in the steps 2a and 2b, a considerable amount of oxygen (or air) is blown or an oxide is added to oxidize and remove the impure metal components. Contains a large amount of oxygen (usually 1000 ppm or more). Therefore, in order to satisfy the standard as a copper alloy,
A reduction step is necessary to reduce the oxygen concentration to about 200 ppm or less. This reduction can of course be carried out according to a conventional method, but since the oxygen concentration of the molten copper after the steps 1 to 3 is very high as described above, the oxygen concentration of the molten copper can be reduced to the target level in a short time. In order to reduce it, it is desired to employ the following reduction method. That is, as a preferable reduction method to be carried out as the step 4, a reducing agent is added to the surface of the molten copper, and an inert gas is blown into the molten metal and / or an inert gas is blown onto the surface of the molten metal. To perform the reduction. That is, when a reducing agent is added to the surface of the molten metal, a reduction reaction occurs on the surface of the molten metal to generate gases such as CO ₂ and CO,
Some of them dissipate upward and some dissolve into the melt. And these CO ₂ and CO dissolved in the molten metal
The gas and the oxygen present in the molten metal are trapped in the inert gas bubbles blown into the molten metal by a partial pressure difference, and are diffused out of the molten metal together with the inert gas. At this time, if the inert gas is also sprayed on the surface of the molten metal, the oxygen floating on the surface of the molten metal is immediately diffused into the upper space without being dissolved again in the molten metal. Reduction can be performed more efficiently. As the reducing agent, a solid reducing agent such as charcoal and a gaseous reducing agent such as hydrogen and CO can be used, and a powdery solid reducing agent such as charcoal is more preferable. Next, the present invention will be described in more detail with reference to examples. However, the present invention is of course not limited to the following examples, and does not exclude the above-mentioned features of the present invention. It is, of course, possible to carry out the present invention with appropriate modifications, and all of them are included in the technical scope of the present invention. Example Material used: 50% electrolytic copper + 50% commercial copper scrap (JIS No. 2 copper wire scrap level) or 50% Cu-3% Fe punched copper alloy scrap Raw material Pretreatment: None [Purification conditions] Step 1 (melting) Melting furnace: 3 tons High frequency grooved induction melting furnace Melting amount: 2 tons Melting temperature: 1200 ° C. or 1100 ° C. Melting atmosphere: Atmospheric process 2a (oxidation treatment) Oxidation means: Oxygen concentration in molten metal after oxygen blowing treatment: 8000 ppm Step 2b (composite oxide treatment) Additive: Fe ₂ O ₃ , electrolytic Fe, Mn or MnO Addition amount: 0.1% by weight of molten metal Processing temperature: 1200 ° C. or 1100 ° C. Step 3 (debris removal) Heating temperature: 1250 ° C Step 4 (reduction treatment) After adding charcoal to the surface of the molten metal at 1% by weight based on the weight of the molten metal, an isolite porous plug (MP-70) 20 mm
Ar gas was blown at 8 liters / minute × 30 minutes using φ (two tubes). In the above experiment, the amount of slag removed in Step 3 (% based on the weight of the molten metal) was measured, and the results shown in Table 1 were obtained. Incidentally, the amounts of impurity elements in the obtained molten metal were all reduced to 20 ppm or less, and the oxygen concentrations were all 200 ppm or less. [Table 1] As is clear from Table 1, the amount of slag can be greatly reduced by heating to an appropriate temperature at the time of removing slag, and accordingly copper or copper discharged together with the slag as copper oxide. It can be seen that alloy loss can be significantly reduced. The present invention is configured as described above, and is capable of recovering copper or copper alloy satisfying the commercial standard from copper or copper alloy raw material containing an impurity element in good yield.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph showing the relationship between the temperature of a molten metal and the concentration of impurity elements in the molten metal at the time of removing slag in step 3.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takayoshi Ikeda 14-1, Chofu-cho, Shimonoseki-shi Kobe Steel, Ltd. Inside the Chofu Works (72) Inventor Eiji Yoshida 14-1, Chofu-cho, Shimonoseki-shi Kobe Steel, Ltd. In-house Chofu Works (72) Inventor Hirofumi Okada 14-1, Nagafu Port Town, Shimonoseki City Kobe Steel Co., Ltd.Kobe Steel Corporation (72) Inventor Ryusuke Hamanaka 14-1, Nagafu Port Town, Shimonoseki City Head of Kobe Steel Works, Ltd. (56) References JP-A-61-217538 (JP, A) JP-A-49-21209 (JP, B1) JP-T-56-501489 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C22B 1/00-61/00

Claims (1)

(57) [Claim 1] One or more of Sn, Fe and Zn, and P
b, Ni, Sb, S, Bi and As.
Upon purifying free copper or a copper alloy material, Step 1: a step of dissolving copper or copper alloy materials, Step 2a: melt by increasing the oxygen concentration in the solution water
Step of oxidizing Sn, Fe, Zn in the slag, Step 2b: Fe, Fe oxide, Mn, Mn oxide in molten metal
At least one selected from the group consisting of
Of Pb, Ni, Sb, S, Bi, As to Fe and / or
Or slag formation as a composite oxide of Mn, Step 3: heating the generated slag to 1225 to 1400 ° C. ,
A method for purifying a copper or copper alloy raw material, comprising sequentially performing a step of returning copper oxide in the slag to the molten metal as copper and then removing the slag, and a step of reducing the molten metal.