JP2008063164A - Method for producing high-purity cobalt compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-purity cobalt compound having 45.0-65.0 wt.% cobalt content of ≥99% purity and high-purity oxidized cobalt which is obtained from the high-purity cobalt compound and has 70.0-80.0 wt.% cobalt content of ≥99% purity and ≤50 ppm sodium content and to provide methods for producing the high-purity cobalt compound and the high-purity oxidized cobalt. <P>SOLUTION: A cobalt raw material is acid-treated by using an acidic aqueous solution to obtain a cobalt ion aqueous solution. The obtained cobalt ion aqueous solution is neutralized by an alkaline aqueous solution to obtain a precipitate of a cobalt compound. The obtained precipitate is cleaned by a decantation method. The cleaned precipitate is separated by a filtration method. The separated precipitate is dried to obtain the high-purity cobalt compound. The obtained high-purity cobalt compound is subjected to dehydration/condensation treatment to obtain oxidized cobalt. The obtained oxidized cobalt is cleaned by the decantation method. The cleaned oxidized cobalt is dried to obtain the high-purity oxidized cobalt. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a high-purity cobalt compound having a purity of 99% or more and a cobalt content of 45.0 to 65.0 wt%, and a cobalt content of 99% or more and a sodium content of 50 ppm or less obtained from these compounds. The present invention relates to 70.0 to 80.0 wt% of high-purity cobalt oxide, and further to a production method thereof.

  High purity cobalt is used in the fields of semiconductor elements, electronic devices, recording elements and the like. The purity of high-purity cobalt used for this purpose is usually 99 to 99.999%. However, in recent years, various impurities (heavy metal, alkali metal, alkaline earth metal, or ions thereof) that are slightly contained in high-purity cobalt due to high integration of these elements or the manufacture of new structural elements. For example, the presence of iron and nickel causes various problems at the interface joint. In addition, it has been recognized that alkali metal elements such as sodium and potassium easily move in the gate insulating film and cause problems such as deterioration of MOS-LSI interface characteristics. It has been demanded.

  Conventionally, in order to obtain high-purity cobalt, a raw material containing metallic cobalt as a raw material and a method of producing metallic cobalt using a cobalt compound or cobalt oxide are generally used. It is necessary to reduce the content of various impurities (heavy metal, alkali metal, or alkaline earth metal) sufficiently in the previous step before making the metal cobalt. As a method for producing such high-purity cobalt, for example, separation of metal elements by wet processing such as solvent extraction, ion exchange, or electrolytic purification, removal of gaseous elements such as oxygen by dry hydrogen gas processing, or float zone melt purification method was there. However, these methods have a problem that it is difficult to control, and it is difficult to supply high-purity cobalt on an industrial scale and in a high yield at a low cost.

  For example, a cobalt chloride material as a cobalt raw material is made into an acidic aqueous solution containing hydrochloric acid by treatment with hydrochloric acid, and impurities such as copper ions are removed by ion exchange chromatography, followed by evaporation to dryness or neutralization with ammonia hydroxide to obtain cobalt chloride. A method is known in which a product or hydroxide is reduced to high purity cobalt (Patent Documents 1 and 2). However, the method of neutralizing with ammonia hydroxide has a problem that the yield of cobalt hydroxide is poor. In addition, the method of evaporating and drying has a problem in terms of cost and working environment because it includes a process that requires excessive cost and hydrogen chloride gas is released.

Therefore, a method has been developed in which neutralization precipitation treatment with sodium hydroxide or potassium hydroxide is carried out to produce a low-cost, large-scale and environmentally friendly condition (Patent Document 3). However, in the neutralization precipitation treatment using these aqueous alkali solutions, a large amount of alkali metals such as sodium and potassium are mixed, resulting in a new problem. In other words, cobalt oxide, which is a raw material for high-purity cobalt, is used as a ceramic material and catalyst material for electronic parts, but alkali metals such as sodium and potassium contained therein are highly reactive, and thus are used in the manufacturing process. This is because it is considered that troubles occur during firing and that electrical resistance is reduced. As a solution to these problems, attempts have been made to remove alkali metals from cobalt oxides and cobalt compounds used as raw materials thereof. However, even when cobalt oxide containing alkali metal is treated by a method such as wet cleaning or volatilization by heating, which is generally used to remove alkali metal, alkali metal is efficiently and completely removed. It was difficult to remove, and it was necessary to reduce in advance the alkali metal content contained in the cobalt compound which is a raw material for cobalt oxide.
JP 2002-105633 A JP 2001-81507 A JP 2006-8463 A

  An object of this invention is to provide the high purity cobalt compound and high purity cobalt oxide which can be used in order to manufacture high purity cobalt, and those manufacturing methods.

  As a result of earnest research to develop a high-purity cobalt that can be produced at low cost, in large quantities, and under environmentally friendly conditions, the inventors have prepared from a cobalt raw material. The cobalt compound is precipitated by neutralizing the acid aqueous solution containing cobalt ions with an alkaline aqueous solution under a specific condition, so that certain undesirable impurities (heavy metal, alkali metal, or alkaline earth metal, or their I found out that contamination of ions) can be minimized. Furthermore, it has been found that the sodium content can be significantly reduced by dehydrating and condensing the high-purity cobalt compound into cobalt oxide and washing with decantation water. Furthermore, it has been found that high-purity cobalt can be obtained at low cost under environmentally friendly conditions by performing reduction to cobalt using this high-purity cobalt oxide. The present invention has been completed based on such findings.

に属する化合物であることを特徴とする。 That is, the high-purity cobalt compound according to the present invention is characterized in that the cobalt content is 45.0 to 65.0 wt% and the cobalt purity is 99% or more. Moreover, the high purity cobalt compound according to the present invention has a cobalt content of 45.0 to 65.0 wt% and a space group of

It is the compound which belongs to.

に属する酸化物であることを特徴とする。また本発明に係る高純度コバルト酸化物は、ナトリウム含有量が５０ｐｐｍ以下である事を特徴とする。 The high-purity cobalt oxide according to the present invention is characterized in that the cobalt content is 70.0 to 80.0 wt% and the cobalt purity is 99% or more. The high-purity cobalt oxide according to the present invention has a cobalt content of 70.0-80.0 wt% and a space group of

It is an oxide belonging to the above. The high-purity cobalt oxide according to the present invention is characterized in that the sodium content is 50 ppm or less.

Furthermore, the method for producing a high purity cobalt compound according to the present invention includes:
The cobalt raw material is acid-treated with an acidic aqueous solution to obtain a cobalt ion aqueous solution,
The cobalt ion aqueous solution is neutralized with an alkaline aqueous solution to obtain a cobalt compound precipitate,
Decantation wash the precipitate,
Filtering and separating the washed precipitate;
The separated precipitate is dried.

  The method for producing a high-purity cobalt compound according to the present invention is characterized in that the cobalt ion aqueous solution is subjected to ion exchange chromatography to remove heavy metal impurities and then neutralized with an alkaline aqueous solution.

  In the method for producing a high purity cobalt compound according to the present invention, the acid aqueous solution is any one of hydrochloric acid, sulfuric acid, hydrofluoric acid, and nitric acid.

  Further, in the method for producing a high purity cobalt compound according to the present invention, the neutralization precipitation treatment is performed by simultaneously stirring the cobalt ion aqueous solution and the alkaline aqueous solution, and maintaining the pH at 8.0 to 12.0. It is characterized by being added to the water in it.

  In the method for producing a high purity cobalt compound according to the present invention, the alkaline aqueous solution is any one of a sodium hydroxide aqueous solution and a potassium hydroxide aqueous solution.

The method for producing a high purity cobalt oxide according to the present invention includes:
The cobalt raw material is acid-treated with an acidic aqueous solution to obtain a cobalt ion aqueous solution,
The cobalt ion aqueous solution is neutralized with an alkaline aqueous solution to obtain a cobalt compound precipitate,
Decantation wash the precipitate,
Filtering and separating the washed precipitate;
The separated precipitate is dried to obtain a high purity cobalt compound,
The cobalt compound is subjected to dehydration condensation treatment to form a cobalt oxide,
Decantation washing the cobalt oxide,
The washed oxide is dried.

  The high purity cobalt oxide production method according to the present invention is characterized in that the cobalt ion aqueous solution is ion-exchange chromatographed to remove heavy metal impurities and then neutralized with an alkaline aqueous solution.

  In the method for producing a high purity cobalt oxide according to the present invention, the acid aqueous solution is any one of hydrochloric acid, sulfuric acid, hydrofluoric acid, and nitric acid.

  Further, in the method for producing a high purity cobalt oxide according to the present invention, the neutralization precipitation treatment is a reaction in which a cobalt ion aqueous solution and an alkaline aqueous solution are simultaneously stirred, and the pH is maintained at 8.0 to 12.0. It is characterized by being added to water in a container.

  In the method for producing a high purity cobalt oxide according to the present invention, the alkaline aqueous solution is either a sodium hydroxide aqueous solution or a potassium hydroxide aqueous solution.

  Moreover, this invention relates to the manufacturing method of the high purity cobalt oxide characterized by the sodium content of a high purity cobalt oxide being 50 ppm or less.

  The present invention also provides a method for producing a high-purity cobalt oxide, characterized in that the weight reduction rate after removing the adhering water during the dehydration condensation is 8.0 to 38.0 wt%. About.

  The present invention is a high-purity cobalt compound having a cobalt content of 45.0 to 65.0 wt% with a purity of 99% or more, and a sodium content of 50 ppm or less obtained via these compounds, and a purity of 99% or more. Is a high purity cobalt oxide having a cobalt content of 70.0 to 80.0 wt%. According to the production method of the present invention, the high-purity cobalt compound and oxide can be produced at low cost, in large quantities, and under environmentally friendly conditions. Moreover, by using such a high-purity cobalt oxide having a cobalt content of 70.0 to 80.0 wt%, high-purity cobalt can be produced at low cost, in large quantities, and under environmentally friendly conditions.

  The best mode for carrying out the invention will be described below with reference to the drawings.

(High purity cobalt compound)
The high-purity cobalt compound of the present invention is a compound having a cobalt content in the range of 45.0 to 65.0 wt%. The high purity cobalt compound of the present invention includes not only a single compound but also a mixture of a plurality of other types of compounds. Such compounds include cobalt hydroxide and cobalt carbonate.

  Here, the cobalt content means the weight percent of cobalt metal in the total weight of the compound. The high-purity cobalt compound of the present invention is characterized in that the cobalt purity is 99% or more, preferably 99.9% or more. Here, the cobalt purity means the content of other elements with respect to cobalt when cobalt and other specific elements contained in the cobalt compound are totaled. Specific examples of other elements include Mg, Al, Si, Ca, Cr, Mn, Na, Fe, Ni, Cu, Zn, and Pb. These contents are calculated as ppm by mass with respect to cobalt. (Concentration of each measured element = total amount of each measured element / total amount of cobalt).

(Method for producing high-purity cobalt compound)
As shown in FIG. 1, the high purity cobalt compound production method of the present invention described above is obtained by acid-treating a cobalt raw material with an acidic aqueous solution to form a cobalt ion aqueous solution. A precipitate of cobalt compound is obtained by neutralization with decantation, the precipitate is decanted and washed, the washed precipitate is separated by filtration, and the separated precipitate is dried. .

  The cobalt raw material which can be used in the method of the present invention is not particularly limited, and a material containing cobalt as a metal or ion can be used. Further, it can be used in a solid state or a solution state. Specific solid raw materials include cobalt sulfate, cobalt nitrate, cobalt acetate, cobalt oxalate, cobalt chloride, cobalt carbonate, cobalt bromide, cobalt formate, and cobalt metal, and solution raw materials include cobalt sulfate and cobalt nitrate. , Cobalt oxalate, cobalt chloride, and cobalt bromide. In particular, use of cobalt chloride, cobalt nitrate, cobalt sulfate, and cobalt metal is preferable. If the purity of cobalt is about 99 to 99.9%, it can be used. Furthermore, it can be used even if other metal ions usually contained as impurities are contained.

  There is no restriction | limiting in particular also about the acid which can be used in the present invention for the purpose of acid-treating the above cobalt raw material to make a cobalt ion aqueous solution, and various inorganic acids that dissolve cobalt in the cobalt raw material can be preferably used. Specific examples include hydrochloric acid, sulfuric acid, nitric acid, and hydrofluoric acid, and hydrochloric acid is particularly preferable. Moreover, what does not contain an impurity as much as possible is preferable. Examples of impurities include heavy metals, alkali metals, alkaline earth metals, and the like. As such an acid aqueous solution, a commercially available one can be used as it is. Regarding hydrochloric acid, it is also preferable to adjust by blowing high purity hydrochloric acid gas into high purity water. There is no restriction | limiting in particular also about acid concentration, What is necessary is just the density | concentration which fully dissolves cobalt of a raw material. Preferably it is about 7-9 mol / L. There is no particular limitation on the dissolution method, and it is preferable to dissolve the solution little by little with stirring using a container of a material and a shape that prevents impurities from being mixed and does not dissolve the impurity metal from the container wall.

  The concentration of the aqueous cobalt solution obtained by the acid treatment is not particularly limited, and is appropriately adjusted to be suitable for the step of obtaining a cobalt compound by neutralization with an alkaline aqueous solution, which is the next step, or the step of anion exchange chromatography. Is possible. Specifically, for the step of obtaining a cobalt compound precipitate by neutralizing with an alkaline aqueous solution, it is in the range of 10 to 100 g / L in terms of the concentration of cobalt ion, and for the step of anion exchange chromatography. It is preferable to adjust to a concentration of 10 to 100 g / L in terms of cobalt ion concentration.

  Moreover, it is preferable to perform elemental analysis of the acid aqueous solution containing cobalt ions obtained before the next step. The method of elemental analysis is not particularly limited, but it is preferable to use a method and apparatus in which the detection limit of cobalt, other heavy metals, alkali metals, and alkaline earth metals is about 1 ppt. Specific examples include an inductively coupled plasma mass spectrometer (ICP-MS).

  The neutralization precipitation treatment of the present invention is characterized in that the obtained cobalt aqueous solution is neutralized with an alkaline aqueous solution to precipitate an insoluble cobalt compound. There are no particular restrictions on the alkaline aqueous solution that can be used here, as long as cobalt ions are precipitated as insoluble compounds and other metal ions other than cobalt ions remain soluble in the aqueous solution. Such an alkaline aqueous solution makes it possible to separate only cobalt ions as an insoluble precipitate. Specifically, sodium hydroxide aqueous solution and potassium hydroxide aqueous solution are mentioned as alkaline aqueous solution. When contamination with sodium ions is to be avoided, it is possible to use a high-purity sodium hydroxide aqueous solution that is commercially available for semiconductor production, which is particularly preferable to use a potassium hydroxide aqueous solution. It is also possible to prepare by dissolving pure sodium hydroxide in high purity water. When sodium, potassium, and magnesium are not problematic as impurities contained in the high-purity cobalt compound, an aqueous sodium hydroxide solution can be preferably used as the alkaline aqueous solution. If sodium, potassium, or magnesium is a problem as impurities contained in high-purity cobalt, control the reaction conditions during neutralization, especially the amount of sodium and potassium mixed into the crystal structure by controlling the pH. Can be reduced. Moreover, the amount of sodium and potassium contained in the high-purity cobalt oxide can be reduced by dehydration and washing with water after neutralization. Although there is no restriction | limiting in particular also about the density | concentration of aqueous alkali solution, What is necessary is just the range of 5-20 mol / L.

  There is no particular limitation on the method of neutralizing the cobalt aqueous solution with the alkaline aqueous solution. A method of adding an alkaline aqueous solution to the aqueous cobalt solution in the reaction vessel or a method of simultaneously adding the aqueous cobalt solution and the aqueous alkaline solution into the reaction vessel can be used. In particular, in the present invention, a preferable method is that the cobalt ion aqueous solution and the alkaline aqueous solution are simultaneously not limited in temperature, but it is preferable to maintain a range of 20 to 80 ° C.

  It can be added with stirring to water in a reaction vessel maintained in the range of 20 to 80 ° C. and maintained at pH 7.0 to 13.0 (preferably 8.0 to 12.0) with an alkaline aqueous solution. preferable. Here, the concentration of the cobalt ion aqueous solution to be added is preferably in the range of 10 to 100 g / L, and the concentration of the alkaline aqueous solution is preferably in the range of 5 to 20 mol / L. The addition rate is not particularly limited, but is preferably in the range of 10 to 70 ml / min. The precipitate produced by neutralization under such conditions precipitates at the bottom of the reaction vessel after the reaction and can be easily separated from the supernatant solution. The pH of the aqueous solution during the reaction is not particularly limited as long as the cobalt ions are in an insoluble cobalt compound, and may be in the range of 8 or more. In the present invention, it is preferable that the cobalt compound is sufficiently separated from the reaction solution to generate a precipitate, and is maintained at 10.0 to 12.0 as a condition that impurities are not mixed into the precipitate.

  The neutralization reaction type is not particularly limited, and can be either a batch type or a continuous type. In the case of the continuous type, the generated high purity cobalt compound precipitate having a cobalt content of 45.0 to 65.0 wt% can be continuously taken out by the overflow pipe provided in the reaction apparatus, which can be carried out more efficiently.

  The present invention is further characterized by decanting the precipitate. Specifically, the decantation washing is to remove the supernatant by removing the supernatant after removing the supernatant aqueous solution, adding pure water to the precipitate, stirring, and letting it stand to settle again at the bottom of the reaction vessel. Means. Such decantation washing (repeated several times if necessary) makes it possible to sufficiently remove water-soluble salts, ions, compounds, and the like adhering to the surface of the precipitate. In particular, it is effective for removing alkali metal ions, particularly sodium ions, used in an alkaline aqueous solution.

  The obtained cobalt compound is separated by filtration and further dried. There is no particular limitation on the method and apparatus for filtering the precipitate, and a generally known method and apparatus for filtering and separating powder substances can be preferably used. Specific examples include a suction filtration method, a filter press method, and a centrifugal separation method. The precipitate separated by filtration can be dried using a generally known method and apparatus for drying a powder substance.

  The decantation cleaning, filtration separation, and drying steps described above are steps that can be appropriately performed when necessary when carrying out the present invention. In particular, the obtained high-purity cobalt compound precipitate having a cobalt content of 45.0 to 65.0% can be sufficiently dried by an ordinary drying method. Specifically, it is kept at 40 to 100 ° C. for 10 to 20 hours in a vacuum drying apparatus.

Further, in the present invention, it is preferable to reduce the concentration of various impurities in the cobalt aqueous solution by pretreating an aqueous cobalt solution with an anion chromatograph before neutralization and precipitation with an alkaline aqueous solution. Metal ions to be removed include nickel, iron and manganese ions. The anion exchanger that can be used in the anion chromatograph is not particularly limited as long as it is an exchanger that can selectively adsorb and desorb cobalt ions and other metal ions. Specific examples of inorganic anion exchangers include zirconium, antimony, magnesium, and aluminum, and examples of organic anion exchangers include quaternary ammonium groups and tertiary amino groups. Can be mentioned. In particular, when the impurities to be removed are divalent cations (copper ions, nickel ions, etc.), it is possible to use a known anion exchange chromatograph (Thin Solid Films 461 (2004) 94-98). .
Such treatment can reduce the concentration of metal ions to be removed to about 0.1% by weight.

に属する物である。空間群はコバルト酸化物をＸ線回折装置で測定して決定することが可能である。 (High purity cobalt oxide)
The high-purity cobalt oxide of the present invention is a compound having a cobalt content in the range of 70.0 to 80.0 wt%. The high-purity cobalt oxide of the present invention includes not only an oxide having a single composition but also a mixture of a plurality of other types of oxides. That is, when expressed in chemical formula, it is CoxOy, where x is in the range of 1 to 3, and y is in the range of 1 to 4. More specifically, CoO, Co2O3, and Co3O4 can be mentioned. The high-purity cobalt oxide of the present invention further contains a hydrate. The cobalt oxide of the present invention has a space group of

It belongs to. The space group can be determined by measuring cobalt oxide with an X-ray diffractometer.

  Here, the cobalt content means the weight percent of cobalt metal in the total weight of the compound. The high-purity cobalt oxide of the present invention is characterized in that the cobalt purity is 99% or more, preferably 99.9% or more. Here, the cobalt purity means the content of other elements with respect to cobalt when cobalt and other specific elements contained in the cobalt oxide are totaled. Specific examples of other elements include Mg, Al, Si, Ca, Cr, Mn, Na, Fe, Ni, Cu, Zn, and Pb. These contents are calculated as ppm by mass with respect to cobalt. (Concentration of each measured element = total amount of each measured element / total amount of cobalt).

(Method for producing high purity cobalt oxide)
As shown in FIG. 1, the high-purity cobalt oxide production method of the present invention is characterized by further subjecting the high-purity cobalt compound of the present invention described above to dehydration condensation treatment. Further, if necessary, the oxide subjected to dehydration condensation treatment is decantated and washed.

That is, in the method for producing a high purity cobalt oxide of the present invention, a cobalt raw material is acid-treated with an acidic aqueous solution to obtain a cobalt ion aqueous solution, and the cobalt ion aqueous solution is neutralized with an alkaline aqueous solution to precipitate a cobalt compound. Decant wash the precipitate,
The washed precipitate is separated by filtration, the separated precipitate is dried to obtain a high-purity cobalt compound, the cobalt compound is subjected to dehydration condensation treatment to obtain cobalt oxide, and the cobalt oxide is decanted and washed. And drying the washed oxide. Moreover, the high-purity cobalt oxide obtained by this method has a cobalt content of 70.0 to 80.0 wt% and a cobalt purity of 99% or more. Moreover, the high-purity cobalt oxide obtained by this method is characterized in that the sodium content is 50 ppm or less.

  The dehydration condensation treatment of the high-purity cobalt compound is not particularly limited as long as it is a treatment for converting the high-purity cobalt compound into cobalt oxide, and generally known dehydration methods can be used. Specific examples include a method using a spray dryer, an agromaster, a dry meister, an electric furnace, or a tubular furnace. The dehydration condensation treatment can be monitored by a method of measuring weight loss, a differential thermobalance. In the present invention, it is particularly preferable that the weight reduction rate is 8.0 to 38.0 wt%, excluding the adhering water during the dehydration condensation treatment.

  Specifically, the obtained high-purity cobalt compound having a cobalt content of 45.0 to 65.0 wt% is subjected to dehydration condensation, washed with water, and then dried to obtain a high-purity cobalt having a cobalt content of 70.0 to 80.0 wt%. It is possible to further reduce the amount of sodium or potassium contained in the oxide. Table 1 shows the relationship between the weight reduction rate and the sodium reduction rate during the dehydration condensation treatment. The weight reduction rate in the state except the adhesion water of the high purity cobalt oxide at the time of the concrete dehydration condensation process is 8.0-38.0 wt%. It can be seen from Table 1 that the weight reduction rate in the state excluding the adhering water during dehydration condensation is preferably 8.0 to 38.0 wt%. If the weight reduction rate is 8.0 wt% or less, the filterability is deteriorated and the working efficiency is poor. Conversely, if the weight reduction rate is 38.0 wt% or more, sodium or potassium contained in the high purity cobalt compound due to aggregation. It can be difficult to reduce this.

  Hereinafter, the present invention will be described in detail based on examples. However, the present invention is not limited to these examples.

(Elemental analysis)
Apparatus: ICP-MS (Optima 4300 DV manufactured by PerkinElmer) was used.

  Sample: Raw material cobalt (cobalt chloride) was dissolved in an aqueous hydrochloric acid solution to prepare an aqueous solution having a concentration of 4 g / L. The cobalt compound or cobalt oxide was dissolved in an aqueous hydrochloric acid solution to prepare an aqueous solution having a concentration of 4 g / L. As the cobalt ion aqueous solution, an aqueous solution having a concentration of 4 g / L was prepared using high-purity water.

  Result: The measurement followed the usage manual of ICP-MS (Optima 4300DV made by PerkinElmer). From the measured cobalt content in the sample, it was calculated as% by weight based on the total amount of the sample, and was defined as Co purity (%).

  Further, the content of ions (Mg, Al, Si, Ca, Cr, Mn, Na, Fe, Ni, Cu, Zn, Pb) in the measured sample was calculated as mass ppm with respect to cobalt (measurement each Element concentration = total amount of each element measured / total amount of cobalt).

(X-ray diffraction pattern)
Apparatus: An X-ray diffraction apparatus (Rint-2200V manufactured by Rigaku) was used.
Sample: Cobalt compound or cobalt oxide was applied to the diffraction apparatus cell in a powder state. If the powder was agglomerated, it was ground with a mortar and applied to the cell for the diffractometer.
Result: The measurement was carried out by identification analysis according to the use manual of the X-ray diffraction apparatus (Rint-2200V manufactured by Rigaku).

(Example 1)
As raw material cobalt, 1610 g of cobalt chloride (manufactured by Ise Chemical Co., Ltd.) was pulverized and dissolved in 15 L of 35% hydrochloric acid (manufactured by Kanto Chemical Co., Ltd., product number 18078-80). Further, 5 L of distilled water was added to make the total volume 20 L (the color of the aqueous solution changed from dark red to dark blue). The elemental analysis results of the acid aqueous solution containing the obtained cobalt ions are shown in Table 2 below.

  Add 3 L of ion exchange distilled water to a reaction vessel (15 L volume made of vinyl chloride, cylindrical vessel with a radius of 13 cm and a height of 25 cm), control the temperature of the water in the reaction vessel to 40 ° C, and add sodium hydroxide to the pH To maintain 11.2. Further, a propeller-shaped stirrer having a radius of 3.5 cm was fixed to the center of the reaction vessel at a rotation speed of 400 rpm and stirred.

  In this reaction vessel, 8 L of the acid aqueous solution containing cobalt ions prepared above and 3.5 L of 48% sodium hydroxide (manufactured by Tsurumi Soda Co., Ltd., Ultra Pure grade, product name CLEARCUT-S) are simultaneously used with a quantitative dropping device. Over 6 hours. The dropping rate of the aqueous acid solution containing cobalt ions was 21 ml / min. A pink precipitate formed with the addition.

  The precipitate was transferred to a beaker, ion-exchanged distilled water was added and stirred, and then allowed to stand to precipitate the precipitate, and the supernatant water was poured off by tilting the beaker (hereinafter referred to as “decantation washing”). After performing decantation washing twice, the precipitate was separated by filtration using a suction filter. The separated precipitate was dried at about 60 ° C. under vacuum for 10 hours to obtain 250 g of a cobalt compound.

  The elemental analysis results of the obtained cobalt compound are shown in Table 3.

  Further, 250 g of a cobalt compound was subjected to dehydration condensation to obtain a cobalt oxide. Thereafter, the cobalt oxide was decanted once and the resulting precipitate was dried at 60 ° C. using a dryer to obtain 630 g of cobalt oxide.

  Table 4 shows the elemental analysis results of the obtained cobalt oxide.

  The cobalt content was 73.3 wt%, and it was found from the X-ray diffraction pattern that the cobalt oxide belongs to the space group Fd3m. Further, the purity of the cobalt oxide was 99.8242%, and the contents of chromium, copper and lead were all 1 ppm or less. The nickel content was 1600.0 ppm. Further, the sodium content was 51.0 ppm, and it can be seen that the sodium content was reduced to about one half compared to the results of Example 2 described below.

(Example 2)
In Example 1, it carried out similarly except not performing decantation washing after dehydration condensation.

  Table 5 shows the elemental analysis results of the obtained cobalt oxide.

に属するコバルト化合物である事が分かった。また、コバルト化合物の純度は９９．８１９５％であり、かつクロム、銅、鉛の含有量はいずれも１ｐｐｍ以下であった。一方ニッケルの含有量は、１６００．０ｐｐｍであり、ナトリウムの含有量は９７．４ｐｐｍであった。 The cobalt content of the obtained cobalt compound is 63.4 wt%, and from the X-ray diffraction pattern

It was found to be a cobalt compound belonging to. Further, the purity of the cobalt compound was 99.8195%, and the contents of chromium, copper and lead were all 1 ppm or less. On the other hand, the nickel content was 1600.0 ppm and the sodium content was 97.4 ppm.

(Example 3)
A column chromatograph using the acid aqueous solution 20L containing cobalt ions prepared in Example 1 using 30 L of anion exchange resin (manufactured by Mitsubishi Chemical Corporation, product name DIAION SA10A, packed in a vinyl chloride column having a diameter of 12 cm), Cobalt ions were adsorbed and separated from other element ions. Next, cobalt ions were eluted with an eluent (concentration: 4 mol / L hydrochloric acid). Elemental analysis of the obtained eluent is shown in Table 6 below.

  The obtained cobalt ion eluent 8L was further subjected to neutralization precipitation treatment under the same conditions as in Example 1. The elemental analysis of the obtained cobalt compound is shown in Table 7 below.

に属するコバルト化合物である事が分かった。また、コバルト化合物の純度は、９９．９９０５％であり、クロム、マンガン、ニッケル、銅、鉛の含有量はいずれも１ｐｐｍ以下であった。しかし、ナトリウムの含有量は、５６．０ｐｐｍと高い事が分かった。 The cobalt content of the obtained cobalt compound is 63.3 wt%, and from the X-ray diffraction pattern.

It was found to be a cobalt compound belonging to. Moreover, the purity of the cobalt compound was 99.9905%, and the contents of chromium, manganese, nickel, copper, and lead were all 1 ppm or less. However, the sodium content was found to be as high as 56.0 ppm.

  Thereafter, the obtained cobalt compound was subjected to dehydration condensation treatment, decantation washed, and dried to obtain a cobalt oxide. The elemental analysis of the obtained cobalt oxide is shown in Table 8 below.

  The obtained cobalt oxide had a cobalt content of 73.4 wt% and was found to be a cobalt oxide belonging to the space group Fd3m from the X-ray diffraction pattern. Further, the purity of the cobalt oxide was 99.99949%, and the contents of chromium, manganese, nickel, copper, and lead were all 1 ppm or less like the cobalt compound. The content of sodium was 9.2 ppm, which was reduced to about 1/6 compared with the cobalt compound value.

Example 4
In Example 3, a high-purity cobalt compound was obtained under the same conditions as above except that decantation washing was not performed after dehydration condensation. Elemental analysis of the obtained eluent is shown in Table 9 below.

に属するコバルト化合物である事が分かった。また、コバルト化合物の純度は、９９．９９１０％であり、クロム、マンガン、ニッケル、銅、鉛の含有量はいずれも１ｐｐｍ以下であった。ナトリウムの含有量は、５４．２ｐｐｍである事が分かった。 The cobalt content of the obtained cobalt compound is 63.0 wt%, and from the X-ray diffraction pattern

It was found to be a cobalt compound belonging to. Moreover, the purity of the cobalt compound was 99.9910%, and the contents of chromium, manganese, nickel, copper, and lead were all 1 ppm or less. The sodium content was found to be 54.2 ppm.

(Example 5) Neutralization precipitation treatment 1 by a continuous method
As a cobalt raw material, an aqueous cobalt chloride solution was prepared as follows. After 1610 g of cobalt chloride (Ise Chemical Co., Ltd.) was dissolved in 15 L of 35% hydrochloric acid, an aqueous solution having a cobalt concentration of 20 g / L was prepared with 5 L of ion-exchanged water. 3 L of water was placed in a reaction vessel equipped with a stirrer, and the pH was adjusted to 11.2 using a sodium hydroxide aqueous solution with a pH controller. A cobalt chloride aqueous solution having a cobalt concentration of 20 g / L and a 48% sodium hydroxide aqueous solution were added thereto so that the pH in the reaction vessel was automatically maintained at 11.2. The input flow rate of the cobalt chloride aqueous solution was 23 ml / min. Moreover, the temperature in a reaction tank was maintained at 40 degreeC, and was always stirred with the stirrer. The produced cobalt compound was overflowed from the overflow tube, taken out, washed with water and dehydrated to obtain a cobalt compound. The elemental analysis of the obtained cobalt compound is shown in Table 10 below.

  Next, as in Example 1, dehydration condensation treatment was performed, followed by decantation washing and drying to obtain a high-purity cobalt oxide. The elemental analysis of the obtained cobalt oxide is shown in Table 11 below.

(Example 6) Continuous process neutralization precipitation process 2
In Example 5, after performing the dehydration condensation treatment, a high-purity cobalt oxide was obtained under the same conditions as above except that decantation washing was not performed. The elemental analysis of the obtained cobalt oxide is shown in Table 12 below.

Comparative Example 1 Neutralization Precipitation Treatment with Ammonia Hydroxide 3 L of ion-exchanged distilled water was added to the reaction vessel used in Example 1, the temperature of the water in the reaction vessel was controlled at 40 ° C., and the pH was adjusted to an aqueous ammonia hydroxide solution. Maintained at 10.0. Further, a propeller-shaped stirrer having a radius of 3.5 cm was fixed to the center of the reaction vessel at a rotation speed of 400 rpm and stirred.

  In this reaction tank, 8 L of the cobalt chloride aqueous solution prepared in Example 3 and 28% ammonia hydroxide aqueous solution (manufactured by Kanto Chemical Co., Ltd., special grade, product number 01266-80) were simultaneously used for 6 hours using a quantitative dropping device. added. A green precipitate was formed with the dropwise addition, but the supernatant was reddish brown, and the cobalt compound was not completely precipitated, resulting in a decrease in yield.

(Comparative example 2) Heating evaporation to dryness method 500 ml of cobalt chloride aqueous solution prepared in Example 3 was put into a 1000 ml cylindrical beaker made of Teflon placed on a hot plate. This was heated to obtain red crystalline cobalt chloride. Elemental analysis of the resulting cobalt chloride was performed (Table 13).

  From the measured values, the purity of cobalt chloride was 99.9934%, and the contents of chromium, manganese, nickel, copper, and lead were 1 ppm or less. The sodium content was 2.6 ppm.

  Moreover, when the energy cost was calculated using the equation shown in the following formula 1, the energy cost required for producing 1 kg of the high purity cobalt compound by the neutralization precipitation treatment is reduced to about one fourth. (See Table 14).

Q = {W × H × E} / Co
Q: Energy cost required to make 1kg of high-purity cobalt compound (yen)
W: Power consumption (kW)
H: Processing time (hr)
E: Unit price (yen / kW)
Co: Cobalt treatment amount (kg)
* The cobalt ion concentration in the acid solution used was 25 g / L.

  According to the present invention, a high-purity cobalt compound (cobalt content: 45.0 to 65.0 wt%) having a purity of 99% or more suitable for the production of high-purity cobalt having a purity of 99.999% or more, and those compounds Production of high purity cobalt oxide (cobalt content: 70.0 to 80.0 wt%) having a sodium content of 50 ppm or less and a purity of 99% or more obtained at low cost and environmentally friendly This is possible under certain conditions.

FIG. 1 is a diagram showing a method for producing a high purity cobalt compound and oxide according to the present invention.

Claims (14)

  A high-purity cobalt compound having a cobalt content of 45.0 to 65.0 wt% and a cobalt purity of 99% or more.   A high-purity cobalt oxide having a cobalt content of 70.0 to 80.0 wt% and a cobalt purity of 99% or more. The cobalt raw material is acid-treated with an acidic aqueous solution to obtain a cobalt ion aqueous solution,
The cobalt ion aqueous solution is neutralized with an alkaline aqueous solution to obtain a cobalt compound precipitate,
Decantation wash the precipitate,
Filtering and separating the washed precipitate;
Drying the separated precipitate,
A method for producing a high-purity cobalt compound having a cobalt content of 45.0 to 65.0 wt% and a cobalt purity of 99% or more.   The method according to claim 3, wherein the cobalt ion aqueous solution is ion-exchange chromatographed to remove heavy metal impurities and then neutralized with an alkaline aqueous solution.   5. The method for producing a high purity cobalt compound according to claim 3, wherein the acid aqueous solution is any one of hydrochloric acid, sulfuric acid, hydrofluoric acid, and nitric acid.   The neutralization precipitation treatment is characterized in that an aqueous cobalt ion solution and an alkaline aqueous solution are simultaneously stirred and added to water in a reaction vessel maintained at a pH of 8.0 to 12.0. The manufacturing method of the high purity cobalt compound in any one of 3-5.   The method for producing a high-purity cobalt compound according to any one of claims 3 to 6, wherein the alkaline aqueous solution is any one of an aqueous sodium hydroxide solution and an aqueous potassium hydroxide solution. The cobalt raw material is acid-treated with an acidic aqueous solution to obtain a cobalt ion aqueous solution,
The cobalt ion aqueous solution is neutralized with an alkaline aqueous solution to obtain a cobalt compound precipitate,
Decantation wash the precipitate,
Filtering and separating the washed precipitate;
The separated precipitate is dried to obtain a high purity cobalt compound,
The cobalt compound is subjected to dehydration condensation treatment to form a cobalt oxide,
Decantation washing the cobalt oxide,
Drying the washed oxide,
A method for producing a high-purity cobalt oxide having a cobalt content of 70.0 to 80.0 wt% and a cobalt purity of 99% or more.   9. The method of high purity cobalt oxide according to claim 8, wherein the cobalt ion aqueous solution is ion exchange chromatographed to remove heavy metal impurities and then neutralized with an alkaline aqueous solution.   10. The method for producing a high purity cobalt oxide according to claim 8, wherein the acid aqueous solution is any one of hydrochloric acid, sulfuric acid, hydrofluoric acid, and nitric acid.   The neutralization precipitation treatment is characterized in that an aqueous cobalt ion solution and an alkaline aqueous solution are simultaneously stirred and added to water in a reaction vessel maintained at a pH of 8.0 to 12.0. The manufacturing method of the high purity cobalt oxide in any one of 8-10.   The method for producing a high-purity cobalt oxide according to any one of claims 8 to 11, wherein the aqueous alkali solution is any one of an aqueous sodium hydroxide solution and an aqueous potassium hydroxide solution.   The method for producing a high purity cobalt oxide according to any one of claims 8 to 12, wherein the sodium content of the high purity cobalt oxide is 50 ppm or less.   The high purity according to any one of claims 8 to 12, wherein the weight reduction rate in the state excluding the adhering water during the dehydration condensation treatment is 8.0 to 38.0 wt%. A method for producing cobalt oxide.

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