JPH082915A - Production of copper oxide - Google Patents

Abstract

PURPOSE:To produce copper oxide reduced in the content of impurities and improved in its sedimentation and filtration properties at a low cost by adding the aqueous solution of the mixture of an alkali hydroxide with an alkali carbonate to an aqueous solution of a copper salt to react the alkali hydroxide and the alkali carbonate with the copper salt. CONSTITUTION:The method for producing the copper oxide comprises separately adding the aqueous solution of 70-95% of sodium hydroxide and the aqueous solution of 30-5% of sodium hydroxide as precipitating agents to e.g. a copper- etching solution having a copper concentration of 50-100g/L for IC boards or an aqueous solution containing a copper salt such as copper chloride, copper sulfate or copper nitrate, reacting the compounds with each other at 70-90 deg.C under stirring, washing and filtering the produced precipitates by a decantation method, dried at approximately 100 deg.C, and subsequently calcined at 250-500 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing pigments, catalysts, coloring agents for glass and earthenware, especially copper oxide which is important as a raw material for ferrite.

[0002]

2. Description of the Related Art There is a simple method for producing copper oxide by heating metallic copper in the atmosphere to form copper oxide, which is used after a stable oxide layer is formed on the surface of metallic copper. In order to prevent the progress of the reaction, in practice, a method of adding an alkali to an aqueous solution of a copper salt to precipitate copper hydroxide, copper carbonate and the like, and then producing copper oxide by thermal decomposition is used. However, since this method is a batch method, cost reduction,
It is disadvantageous to rationalize the equipment, and it is desired to establish the manufacturing technology by the continuous method in order to minimize the quality variation.

[0003]

DISCLOSURE OF THE INVENTION The present invention aims to improve the conventional batch system and provide a method for producing copper oxide having a low content of impurities such as sodium and chlorine and having good sedimentation and filterability. To do.

[0004]

Means for Solving the Problems In order to solve the above problems, the present inventor has studied in detail the general method for producing copper oxide and the basic matters concerning the copper oxide of the product, and as a result, an aqueous solution of copper salt. It was found that the addition of a mixed aqueous solution of an alkali hydroxide and an alkali carbonate to a copper oxide yields copper oxide having excellent properties that have never been obtained, and the present invention has been accomplished. That is, the present invention is characterized in that a mixed aqueous solution of an alkali hydroxide and an alkali carbonate is added to an aqueous solution of a copper salt, reacted with heating and stirring, and the generated precipitate is separated and calcined at a temperature of 250 to 500 ° C. The gist is a method for producing copper oxide.

More specifically, the method of the present invention starts from a copper etching waste liquid of an IC substrate or an aqueous solution containing a copper salt such as copper chloride, copper nitrate or copper sulfate. The copper concentration when using the etching waste liquid is generally in the range of 50 to 100 g / L. To this aqueous solution, a mixed aqueous solution of alkali hydroxide and alkali carbonate is added as a precipitant.

The present inventor conducted the following experiment when this mixed aqueous solution was not used. To the etching waste liquid (50 to 100 g / L of copper), as a precipitating agent, 1 to 2 equivalents of sodium carbonate and sodium hydroxide aqueous solution were separately added, respectively, and reacted at 70 to 90 ° C. After that, the generated precipitate was washed by a decantation method, filtered, dried at about 100 ° C., and then calcined at 400 ° C. The results are shown in Table 1.

[0007]

[Table 1]

From this table, there are differences in the oxide precipitates obtained by the precipitant, and the precipitates obtained when sodium carbonate is added have good settling properties and filterability, but there are impurities in the calcined product. The content of Na and Cl is high, and the amount of Cu in the supernatant is higher than the standard value of 3 ppm of wastewater. On the contrary, in the case of sodium hydroxide, the sedimentation and precipitation of precipitates are not good, but decane The impurities Na and Cl
Content was low, the concentration of Cu in the supernatant was 1 ppm or less, and the precipitate was confirmed to be copper oxide by X-ray diffraction.

From these results, various studies were conducted to utilize the characteristics of sodium hydroxide and sodium carbonate as a precipitant in the present invention. As a result, it was confirmed that a mixed solution of both specific ratios exhibited excellent effects. It is said that the proportion of alkali hydroxide of 70 to 95% and the proportion of alkali carbonate of 30 to 5% with respect to the equivalent of copper contained therein are indispensable for obtaining the effect of the present invention.

[0010]

EXAMPLES Examples will be given below, but the present invention is not limited thereto. (Example 1) 0.82 mol / L of copper chloride solution obtained by diluting copper etching waste liquid with water in a 3 L reaction tank (Cu 52 g
/ L), using a mixed aqueous solution of 2.09N sodium hydroxide and 0.52N sodium carbonate at a constant rate of 1.0L / hr from the head tank, maintaining the reaction temperature at 80 ± 2 ° C. and stirring the reaction. The copper oxide was dropped into the tank to continuously produce copper oxide. In this case, the mixing ratio of sodium hydroxide and sodium carbonate is 80% and 20%, respectively, with respect to the amount of copper,
The amount of alkali added was 1.2 times the equivalent of copper. The residence time in the reaction tank was about 1 hour.

The copper oxide produced is continuously withdrawn, washed twice by decantation, filtered and washed with water to about 100.degree.
After being dried at 4, the product was calcined at 400 ° C and 900 ° C.
The analytical values of the obtained product are shown in Table 2. The purity of copper oxide is 99.0% CuO and impurities Na and Cl
Was 0.01% or less than 0.01%, respectively.
The color tone of the precipitate was black, the filterability was good, and Cu in the supernatant was 1 to 3 ppm.

[0012]

[Table 2]

(Example 2) 0.83 mol / L of copper chloride solution prepared by diluting copper etching waste liquid with water in a 3 L reactor.
(Cu 52 g / L) 1. Using a mixed aqueous solution of 2.35 N sodium hydroxide and 0.26 N sodium carbonate.
From the head tank at a constant speed of 0 L / hr, reaction temperature 8
The mixture was added dropwise to the stirred reaction tank kept at 0 ± 2 ° C. to continuously produce copper oxide. In this case, the mixing ratio of sodium hydroxide and sodium carbonate is 90% with respect to the amount of copper.
% And 10%, and the addition amount of alkali is 1.
It was doubled. The residence time in the reaction tank was about 1 hour and 20 minutes.

The copper oxide produced is continuously withdrawn, washed twice by decantation, filtered and washed with water to about 100 ° C.
After being dried at 4, the product was calcined at 400 ° C and 900 ° C.
The analytical values of the obtained products are shown in Table 2. The purity of copper oxide is CuO 99.0% or more, and the particularly problematic impurities Na and Cl are 0.01% or 0.01% or less, respectively. It was The color tone of the precipitate was blackish brown, the filterability was normal, and Cu in the supernatant was 0.5 to 1 ppm.

[0015]

INDUSTRIAL APPLICABILITY According to the method of the present invention, copper oxide can be efficiently produced not only from an aqueous solution of a copper salt (copper chloride, copper nitrate, copper sulfate, etc.) but also from an etching waste liquid of copper. It is effective from the aspect, and can supply stable quality copper oxide at low cost.

Claims (2)

[Claims] 1. A mixed aqueous solution of an alkali hydroxide and an alkali carbonate is added to an aqueous solution of a copper salt, and the mixture is reacted under heating and stirring,
A method for producing copper oxide, characterized in that the produced precipitate is calcined at a temperature of 250 to 500 ° C. after fractionation. 2. The mixing ratio of the alkali hydroxide and alkali carbonate is 70-95% alkali hydroxide and 30 alkali carbonate.
It is a ratio of -5%, The manufacturing method of the copper oxide of Claim 1 characterized by the above-mentioned.