JP2007270243A - Dry type refining method for copper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for removing tin in crude copper by dry type refining where the content of tin in crude copper can be made into a low level, and further, the content of tin can be controlled to ≤0.33 mass%. <P>SOLUTION: In the dry type refining method, copper, noble metal scrap raw materials including copper, at least one or more kinds of noble metals selected from gold, silver, platinum, rhodium and ruthenium, and tin are melted and reduced together with a solvent and a reducing agent, after separation into the reduced slag and the reduced metal, the melted and reduced metal is subjected to oxidative crude refining for 0.5 to 7 hr with air at a flow rate of 0.5 to 3 L/min/kg-metal, and, in the case the grade of the copper in the crude copper after the oxidative crude refining is <4 mass%, sodium hydroxide is added by an equivalent of 4.5 or above to the tin in the crude copper, and the same is melted and oxidized for 0.5 to 3 hr with an oxygen-containing gas at a flow rate of ≤3 L/min/kg-metal, thus the tin in the crude copper is removed to a grade at which the electrorefining of the copper is possible or below. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a method for removing tin in crude copper by dry refining.

In general, electrolytic copper in copper smelting is produced by the following process. First, copper concentrate is melted in a flash furnace or a reflection furnace, and then the crude copper obtained by oxidation in a converter is refined in a refining furnace, and the obtained refined crude copper having a purity of 98 to 99 mass% is subjected to copper electrolytic purification. As an anode plate (hereinafter referred to as an anode) for casting.

Next, anodes and cathode plates (hereinafter referred to as cathodes) obtained by casting are alternately arranged at regular intervals in an electrolytic cell containing a copper electrolyte, and current density: 250 A / m ² or more. The copper ion eluted into the electrolyte from the anode, which is refined crude copper, was electrodeposited on the cathode under the condition that the current of no current was applied, and the copper quality was 99.99 mass.
% Or more of electrolytic copper is produced.

On the other hand, when reusing copper, a precious metal such as gold, silver, platinum and palladium, copper containing tin, precious metal scrap, etc. as a smelting raw material, that is, copper and precious metal scrap electronic parts Recycled raw materials made from materials, power supply boards, lead frames, plating scraps, and waste liquid-treated residues containing noble metals generated from the precious metal hydrometallurgical process, and obtained crude copper after smelting reduction The metal contains several mass-% tin according to the tin content in the raw material.

In order to remove impurities such as tin in the crude copper, oxidation purification is performed using a gas containing oxygen such as air. In this method, impurities such as tin are obtained up to an anode grade capable of electrolytic purification of copper. In the case of oxidation removal, the oxidation removal efficiency is poor and an oxidation time is required. In addition, in the step of oxidizing and removing impurities such as tin, the efficiency of copper transfer to the oxidized and refined slag is increased, and the amount of oxidized slag that is repeated in the reduction step is increased, which may reduce the production efficiency. For this reason, currently, copper wire scraps, waste copper, and other recycled raw materials with relatively high copper grades are processed by mixing copper, noble metal and tin-containing copper, and precious metal scraps in small amounts. Can not.

In this way, when copper is subjected to electrolytic purification using crude copper containing a high concentration of tin as an anode, tin forms a floating slime in the electrolytic solution and is entrained in the electrolytic copper. Improve impurity quality. In addition, floating slime may adhere to the anode surface and cause passivation. Furthermore, since a scale is formed on the piping and the like, and ultimately the piping and the like are blocked, it becomes an obstacle to equipment maintenance. For this reason, it is preferable that the tin content in the anode described in Japanese Patent Application No. 2006-054296 by the applicants is 0.33 mass-% or less.

In the known dry refining process of lead, as a method of removing tin from molten lead by utilizing the affinity with a basic oxide, sodium hydroxide and sodium nitrate are used at 500 ° C. A technique for separating tin from lead (hereinafter referred to as the Harris method) is known as a Harris soot containing sodium stannate (Na ₂ SnO ₃ ) at the following temperatures. The technology to remove has not been disclosed so far. In addition, when sodium nitrate is used in the Harris method, since sodium nitrate is decomposed and NOx gas is generated, it is necessary to consider measures for treating NOx in the exhaust gas.

Patent application 2006-054296 Lecture ・ Contemporary Metallurgy Smelting 2 Nonferrous Metal Smelting (Published by the Japan Institute of Metals) P137

Then, the subject of this invention solves the problem of the above-mentioned prior art, and in dry refining, it is possible to make the tin quality in crude copper into 0.33 mass-% or less without using sodium nitrate. Provided is a method for removing tin in crude copper by dry refining.

The present invention solves the above problems,
(1) Copper, gold, silver, platinum, palladium, rhodium, ruthenium (hereinafter referred to as noble metal) at least one kind of noble metal, copper containing tin, noble metal scrap raw material and solvent (calcium carbonate, silicon oxide) Etc.) and a reducing agent (coke etc.)
After reducing slag and reduced metal,
The smelting reduction metal is subjected to rough oxidation by oxidation at a flow rate of 0.5-3 L / min / kg-metal for 0.5-7 hours,
When the tin grade in the crude copper after rough oxidation purification is less than 4 mass%, sodium hydroxide is added in an amount of 4.5 equivalents or more to the tin in the crude copper, and the oxygen-containing gas is 3 L / min / kg-metal. It is melted and oxidized at the following flow rate for 0.5 to 3 hours,
A dry refining method for copper, in which tin in crude copper is removed to a quality that allows electrolytic purification of copper.
(2) In the description of (1) above, when the tin quality in the crude copper after the rough oxidation purification is 4 mass-% or more of crude copper,
2 equivalents or more of sodium hydroxide is added to tin in the crude copper, and a gas containing oxygen such as air is melted and oxidized at a flow rate of 3 L / min / kg-metal or less for 0.5 to 3 hours,
A dry refining method for copper, in which tin in crude copper is removed to a quality that allows electrolytic purification of copper.
(3) The dry refining method of copper, wherein the oxidation purification temperature of crude copper is in the range of 1,150 ° C to 1,500 ° C.

The present invention has the following effects.
(1) In dry refining of crude copper, tin in molten copper can be efficiently removed, so that at least one kind of noble metal and tin among copper, gold, silver, platinum, palladium, rhodium, and ruthenium The contained copper and precious metal scrap raw materials can be melt-reduced regardless of the tin content.
(2) In the dry refining of crude copper, tin in the molten copper can be efficiently removed, so that the copper transfer rate to the slag in the oxidative refining process is reduced, and the amount of repeated copper treatment can be reduced. .
(3) In dry refining of crude copper, tin in the molten copper can be efficiently removed, so that the oxidation purification time can be shortened and productivity is improved.

The processing object of the present invention includes copper and at least one kind of noble metal of gold, silver, platinum, palladium, rhodium, and ruthenium, copper containing tin, electronic component material of noble metal scrap, power supply board, lead frame, Recycled raw materials made from waste after treatment with waste liquid containing precious metals generated from the wet refining process of plating scraps and precious metals as a raw material together with calcium carbonate and / or silicon dioxide as a solvent, and coke as a reducing agent, Melting reduction treatment is performed at a melting temperature of 1,200 to 1,600 ° C. for 0.5 to 4 hours to separate reduced slag and reduced metal. The reduced metal thus separated is subjected to rough oxidation by oxidation at a temperature range of 1,150 to 1,500 ° C. and a flow rate of 0.5 to 3 L / min / kg-metal for 0.5 to 7 hours, and then an oxidation furnace Extract the oxidized slag from the inside and separate it from the metal oxide.

Next, sodium hydroxide is added to the metal oxide after the crude oxidation purification to remove tin in the crude copper.
In this case, it is not economically preferable to use a large amount of sodium hydroxide for the purification treatment, and the minimum necessary so that the tin quality in the anode becomes 0.33 mass-% or less, which enables the copper electrolytic purification process in the subsequent step. Of sodium hydroxide is added.
This provides an economically efficient reduction melting and oxidation purification treatment.
In the present invention, the required amount of sodium hydroxide added depends on the tin quality in the crude copper, and when the tin quality is less than 4 mass-%, the theoretical amount is 4.5 equivalents or more with respect to tin and the tin quality is 4 mass. It has been found that when it is-% or more, it is 2 equivalents or more of the theoretical amount with respect to tin.

Next, the present invention will be further described using examples.
(Example-1)
Incinerate at least one precious metal of copper and gold, silver, platinum, palladium, rhodium, ruthenium, copper containing tin, precious metal scrap, combustible electronic component materials, power supply boards, etc. in a fixed furnace Copper, noble metal scrap raw material 60 kg, plating scraps 140 kg of electronic component materials, waste liquid treatment residue 20 kg containing noble metal generated from the precious metal hydrometallurgical process, calcium carbonate 26 kg as a solvent, and coke 15 kg as a reducing agent In a smelting reduction furnace, after smelting reduction treatment at 1,300 to 1,400 ° C. for 3 hours, 146 kg of reducing metal and 68 kg of reducing slag were separated. After this reduced metal was melted in an oxidation furnace at a temperature range of 1,200 ° C. to 1,250 ° C., air was blown in from the tuyere at a flow rate of 0.8 L / min / kg-metal for 2 hours. Thereafter, a roughly oxidized metal was collected from the oxidation furnace. The copper grade in this rough oxidized metal is 96.5 mass-%, and the tin grade is 1.0.
They were mass-%, gold grade 320 mass-ppm, platinum grade 15 mass-ppm, and palladium grade 110 mass-ppm.

Both the crude oxidized metal and sodium hydroxide were sampled according to each condition, mixed in a high-quality alumina crucible, and melted at 1,200 ° C. using an externally heated electric furnace. It was melt oxidized for a time. Thereafter, a high-quality alumina crucible was taken out from the external heating type electric furnace and cooled to separate the metal oxide and slag, and the results of analysis of each component in the metal are shown in Table 1.

As can be seen from the results shown in Table 1, in Example-1, the tin quality is 0.33 mass% or less in the anode in which no passivation occurs in electrolytic refining of copper and no floating slime due to tin is generated. Therefore, it can be seen that sodium hydroxide should be added to the theoretical equivalent of 4.4 equivalents or more with respect to tin.

(Example-2)
In Example-1, the oxidized coarsely purified metal and the reagent tin metal were placed in a graphite crucible so that the tin quality of the produced oxidized roughly purified metal was 2 mass-%, and an external heating electric furnace was used. It was melted at 1,200 ° C. for 1 hour. Thereafter, the graphite crucible was taken out from the external heating type electric furnace and cooled to obtain a metal adjusted to a tin quality of 2 mass-%.

The analysis was carried out in the same manner as in Example 1 except that the metal produced as described above and having a tin quality adjusted to 2 mass-% was used. The results are shown in Table 2.

As can be seen from the results in Table 2, the tin removal treatment of Example-2 is an anode that can be electrolyzed in the copper electrolytic refining process if sodium hydroxide is added in an amount of 4.5 equivalents or more of the theoretical amount to tin. You can get quality.

(Example-3)
In Example-1, the oxidized crude refined metal and the reagent tin metal were placed in a graphite crucible so that the tin quality of the produced oxidized crude refined metal was 4 mass-%, and an external heating electric furnace was used. It was melted at 1,200 ° C. for 1 hour. Thereafter, the graphite crucible was taken out from the external heating type electric furnace and cooled to obtain a metal adjusted to a tin quality of 4 mass-%.

The analysis was carried out in the same manner as in Example 1 except that the metal produced as described above and having a tin quality adjusted to 4 mass-% was used. The results are shown in Table 3.

Table 3 shows the results of analysis performed in the same manner as in Example 1 except that copper metal having a tin quality of 4 mass-% produced as described above was used.

As can be seen from the results in Table 3, in the tin removal treatment of Example 3, an anode quality which can be electrolyzed is obtained in the electrolytic purification process of copper if sodium hydroxide is added in an amount of 2 equivalents or more of the theoretical amount with respect to tin. be able to.

(Example-4)
In Example 1, except that the treatment temperature was in the range of 1,150 ° C. to 1,500 ° C. under the condition that the amount of sodium hydroxide added was 4.5 equivalents of the theoretical amount to tin. Similarly, oxidative purification with sodium hydroxide was carried out.

As can be seen from the results in Table 4, if the condition is 4.5 equivalents of the theoretical amount of sodium hydroxide to tin, the electrolytic purification process of copper can be performed even at a treatment temperature range of 1,150 to 1,500 ° C. It was found that an anode quality capable of electrolysis can be obtained.

An aspect of the processing flow of the present invention is shown. An aspect of the processing flow of the conventional method is shown.

Claims (3)

Copper, gold, silver, platinum, palladium, rhodium, ruthenium (hereinafter referred to as noble metal), at least one kind of noble metal, copper containing tin, noble metal scrap raw material, solvent, and reducing agent are melted and reduced. After separating slag and reduced metal,
The smelting reduction metal is subjected to rough oxidation by oxidation at a flow rate of 0.5-3 L / min / kg-metal for 0.5-7 hours,
When the tin grade in the crude copper after rough oxidation purification is less than 4 mass%, sodium hydroxide is added in an amount of 4.5 equivalents or more to the tin in the crude copper, and the oxygen-containing gas is 3 L / min / kg-metal. It is melted and oxidized at the following flow rate for 0.5 to 3 hours,
A dry refining method for copper, characterized in that tin in crude copper is removed to a quality that enables electrolytic purification of copper. In claim 1, in the case of crude copper having a tin quality of 4 mass-% or more in crude copper after rough oxidation purification,
2 equivalents or more of sodium hydroxide is added to tin in the crude copper, and a gas containing oxygen such as air is melt-oxidized at a flow rate of 3 L / min / kg-metal or less for 0.5 to 3 hours,
A dry refining method for copper, characterized in that tin in crude copper is removed to a quality that enables electrolytic purification of copper. The method for dry refining copper according to claim 1 or 2, wherein the oxidation purification temperature of the crude copper is in the range of 1,150 ° C to 1,500 ° C.