JPH04131310A - Manufacture of high purity steel powder - Google Patents

Abstract

PURPOSE:To manufacture high purity copper powder by executing four processes of metallic copper precipitation, magnetic separating treatment, reduction treatment and drying treatment after forming oxidation preventing film to iron chloride solution containing copper. CONSTITUTION:Into the iron chloride solution containing copper, iron powder is charged and the metallic copper is precipitated and deposited (the first process), and this is taken out and after executing water washing treatment, the magnetic separating treatment is executed (the second process), and the reduction treatment is executed to the copper powder executing the magnetic separating treatment by using hydrogen gas (the third process), and after applying the oxidation preventing film on the copper powder, the drying treatment is executed (the fourth process). By this method, the copper fine powder having high purity and even particle size can be comparatively easily manufactured.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing high-purity copper powder from a copper-containing iron chloride solution (including iron chloride waste liquid) [Prior Art] Generally, Various methods have long been proposed for recovering valuable elements from waste liquid.

As a typical example, as shown in JP-A-41-123926, chalcopyrite etc. are added to a solution containing copper,
A method has been proposed in which copper is recovered as sulfide through a pressure reaction at 100 to 200°C.

[Problem to be solved by the invention]

However, even if copper is recovered as sulfide by the above method, there is a problem in that it is necessary to further perform a secondary treatment to obtain pure copper, and it is difficult to obtain fine tR powder.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a method for producing copper powder that is relatively easy to produce and has high purity.

[Means to solve the problem]

The method for producing high-purity copper powder according to the present invention that meets the above objectives is as follows:
A first step in which iron powder is put into an iron chloride solution containing copper to precipitate metallic copper, a second step in which the precipitate is taken out and washed with water, and then subjected to magnetic separation treatment, and the magnetic separation treatment is performed. The method includes a third step in which the copper powder is subjected to a reduction treatment using hydrogen gas, and a fourth step in which the reduced copper powder is coated with an antioxidant coating and dried.

Note that, in addition to iron powder produced by ordinary mechanical processing (or chemical processing in some cases), it is also possible to use converter recovered refined iron powder (referred to as OGP) as the above-mentioned iron powder. In particular, it is preferable to use OGP because, unlike other iron powders, it is easy to obtain fine powder steel because of the shape of the active surface and its shape characteristics (spherical shape).

In addition, if the second step of classifying the precipitate in the first step, for example, using a wet cyclone and magnetic separation treatment of the recovered material is used, instead of washing the precipitate with water such as Eakins, it is easier to obtain fine copper powder. Can produce good results.

[Effect]

In the first step, copper is precipitated by the following reaction by adding iron powder to the iron chloride solution.

2FeCI3 + Fe −+ 3FeC1zCu
C1z + Fe − + FeCIz
The +Cu produced copper adheres to the periphery of the excessively charged iron powder or precipitates as a single copper. The temperature of the solution at this time was 40-1. O0°C3ORP C redox potential) is O
It is preferable to conduct the test at a voltage of about 350 mV.

Next, in the second step, the precipitate is taken out and washed with water to remove the attached chlorine bones, and then subjected to magnetic separation to completely remove the iron-containing boron content. Copper powder is collected.

In the third step, the copper powder produced in the above step is reduced by heating to 100° C. or higher using hydrogen gas.

This reaction is shown below.

CuO+82 →Cu + H2O As a result, the partially oxidized copper becomes reduced to pure copper, so in the fourth step, to prevent it from oxidizing again,
An antioxidant is added to form an antioxidant film on the surface, and the material is heated and dried at a temperature that does not destroy the antioxidant film. This makes it possible to produce 99.9% or more pure copper.

Furthermore, in the second step, by classifying the precipitate with a cyclone, impurities can be separated and high purity can be achieved. This is because when Akins is used for the water washing process in the second step, a large amount of water is supplied due to the mechanism, and carryover of copper powder occurs due to the flow rate, whereas wet cyclone uses a small amount of overflow water. This has advantages such as prevention of carryover and the ability to arbitrarily select the classification particle size.

C Embodiment] Next, embodiments embodying the present invention will be described with reference to the attached drawings to provide an understanding of the present invention.

First, an iron chloride-based waste liquid (e.g., etching waste liquid) 10, which is an example of an iron chloride-based solution, is prepared, placed in a stirring tank 11, and stirred while adding recovered and refined iron powder recovered from a converter, which is an example of iron powder. . In this case, the ORP is maintained at about 0 to -350+V, and the solution is heated from the surroundings with hot water or electricity so that the temperature is 40 to 100''C.

As a result, the copper contained in the iron chloride waste liquid precipitates and becomes a suspension, as shown by the chemical formula above.
The mixture is placed in a separately prepared sedimentation tank 12, and the precipitate is taken out and placed in a container I3. In this case, it is preferable to fill the container 13 with water so that the recovered precipitate 14 is not oxidized.

Next, this sediment 14 contains chlorine bones (8
~10%), so it is necessary to remove it by washing with water, but this is done while stirring and moving it gradually to the top using the Akins 16. In this case, a water outlet is placed within 1 m from where the precipitate 14 is scraped up by the Eakins 16 to sufficiently remove the chloride solution, and the flung precipitate 14 is exposed to the air. Therefore, an antioxidant (BT-7 manufactured by Shibaike Kogyo Co., Ltd.) is mixed in the upper part of the Akins 16 so that each particle is covered with a film of the antioxidant, and collected in a container 17. In addition, if the stirring capacity of the above-mentioned Akins is insufficient, it is also possible to perform air bubbling or nitrogen gas bubbling to prevent oxidation. This reduces the chlorine content to 0.05% or less.

Next, the precipitate (containing about 65% copper and about 20% iron) collected in the container is subjected to magnetic separation using a magnetic separator 18. Here, a device that generates a magnetic field of about 2,000 to 10,000 Gauss was used. By increasing the magnetic field of the magnetic separator 18 and passing it through multiple times (5 or more times), pure copper powder having a purity of 99% or more can be recovered as a final product.

Next, since the copper powder contains copper oxide, it is placed in hydrogen gas and subjected to a 7-8H reduction treatment at a high temperature (approximately 800"C). In this case, the anti-oxidation film that was attached is 150'C
It will break and vaporize and disappear.

After that, the reduced copper powder is cooled in a non-oxidizing atmosphere,
The above antioxidant is applied again to form an antioxidant coating on the surface of the copper powder.

In this case, the antioxidant may be mixed in using the Akins mentioned above, but in order to prevent the mixing of previous raw materials, it is also possible to prepare the Akins in separate equipment, and furthermore, the antioxidant may be mixed in with a mixer etc. may be mixed in a predetermined amount.

Next, the copper powder with the anti-oxidation coating formed thereon is dried by airflow. In this case, if the drying temperature exceeds 150°C, the antioxidant coating will be destroyed, so drying is usually done using hot air at about 120°C.The particle size of the fine copper powder produced in this way is 20°C. It was about ~30 μm.

In addition, in this example, iron chloride-based waste liquid was used as the raw material, but it is also possible to use an iron chloride solution in which copper is dissolved.Furthermore, OGP was used as the iron powder, but ordinary refined It is also possible to use iron powder. Furthermore,
In this example, the case of Eakins was described as the water washing process, but in addition to this, a case where the precipitate was washed and separated using a wet cyclone and the precipitate was collected and treated in the same manner as described above was also carried out.
A copper purity of 99.9% or more and a higher recovery yield than Ekins were obtained.

〔Effect of the invention〕

As is clear from the above explanation, the method for producing high-purity copper powder according to the present invention has been found to be able to produce fine powder with high purity and uniform grains using relatively simple equipment.

In addition, enching waste liquid is used as an iron chloride solution,
Since it is also possible to use converter recovered and purified iron powder as the iron powder, this allows effective recycling of waste as a resource.

[Brief explanation of the drawing]

FIG. 1 is a flow diagram showing a method for producing high-purity copper powder according to an embodiment of the present invention. (Explanation of symbols) 10- Iron chloride waste liquid, 11- Stirring tank, 12-1--
=-Sedimentation tank, 13--Container, 14 Precipitate, 16-1--Akins, 17--Container, 18--Magnetic separator

Claims (1)

[Claims] (1) A first step in which iron powder is added to an iron chloride solution containing copper to precipitate metallic copper, a second step in which the precipitate is taken out and washed with water, and then subjected to magnetic separation treatment; and the magnetic separation treatment The method is characterized by comprising a third step of subjecting the reduced copper powder to a reduction treatment using hydrogen gas, and a fourth step of applying an antioxidant coating to the reduced copper powder and drying it. A method for producing high-purity copper powder.