JP2018162173A - Method for producing nickel oxide fine powder - Google Patents
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- 239000000843 powder Substances 0.000 title claims abstract description 127
- 229910000480 nickel oxide Inorganic materials 0.000 title claims abstract description 123
- GNRSAWUEBMWBQH-UHFFFAOYSA-N oxonickel Chemical compound [Ni]=O GNRSAWUEBMWBQH-UHFFFAOYSA-N 0.000 title claims abstract description 123
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 40
- 238000010438 heat treatment Methods 0.000 claims abstract description 51
- 238000005406 washing Methods 0.000 claims abstract description 39
- BFDHFSHZJLFAMC-UHFFFAOYSA-L nickel(ii) hydroxide Chemical compound [OH-].[OH-].[Ni+2] BFDHFSHZJLFAMC-UHFFFAOYSA-L 0.000 claims abstract description 34
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 33
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims abstract description 32
- 239000011593 sulfur Substances 0.000 claims abstract description 32
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 32
- 239000007864 aqueous solution Substances 0.000 claims abstract description 29
- 239000003513 alkali Substances 0.000 claims abstract description 21
- 239000002002 slurry Substances 0.000 claims abstract description 20
- 150000002815 nickel Chemical class 0.000 claims abstract description 18
- LGQLOGILCSXPEA-UHFFFAOYSA-L nickel sulfate Chemical compound [Ni+2].[O-]S([O-])(=O)=O LGQLOGILCSXPEA-UHFFFAOYSA-L 0.000 claims abstract description 18
- 229910000363 nickel(II) sulfate Inorganic materials 0.000 claims abstract description 18
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims abstract description 12
- 239000012530 fluid Substances 0.000 claims abstract description 3
- 238000000034 method Methods 0.000 claims description 35
- 238000004140 cleaning Methods 0.000 claims description 14
- 239000011734 sodium Substances 0.000 claims description 12
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 11
- 229910052708 sodium Inorganic materials 0.000 claims description 11
- 238000003756 stirring Methods 0.000 claims description 11
- 239000012535 impurity Substances 0.000 abstract description 24
- 239000000243 solution Substances 0.000 abstract description 14
- 239000002245 particle Substances 0.000 description 69
- 150000001450 anions Chemical class 0.000 description 24
- 239000007788 liquid Substances 0.000 description 20
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 17
- 229940053662 nickel sulfate Drugs 0.000 description 16
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 15
- 238000006243 chemical reaction Methods 0.000 description 12
- 239000007789 gas Substances 0.000 description 11
- 230000000694 effects Effects 0.000 description 10
- 239000000463 material Substances 0.000 description 10
- 238000006386 neutralization reaction Methods 0.000 description 9
- 229910052759 nickel Inorganic materials 0.000 description 9
- 238000005245 sintering Methods 0.000 description 8
- 238000002156 mixing Methods 0.000 description 7
- 239000002994 raw material Substances 0.000 description 7
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 6
- 238000010298 pulverizing process Methods 0.000 description 6
- 239000002904 solvent Substances 0.000 description 6
- 125000000129 anionic group Chemical group 0.000 description 5
- 239000000460 chlorine Substances 0.000 description 5
- 238000010304 firing Methods 0.000 description 5
- 239000007787 solid Substances 0.000 description 5
- QAOWNCQODCNURD-UHFFFAOYSA-L sulfate group Chemical group S(=O)(=O)([O-])[O-] QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 5
- 229910000859 α-Fe Inorganic materials 0.000 description 5
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 4
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 4
- 229910052801 chlorine Inorganic materials 0.000 description 4
- 239000012065 filter cake Substances 0.000 description 4
- 238000001914 filtration Methods 0.000 description 4
- 229910052726 zirconium Inorganic materials 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 238000000227 grinding Methods 0.000 description 3
- 230000001590 oxidative effect Effects 0.000 description 3
- 238000000790 scattering method Methods 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 230000000930 thermomechanical effect Effects 0.000 description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 2
- 239000012295 chemical reaction liquid Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 230000018044 dehydration Effects 0.000 description 2
- 238000006297 dehydration reaction Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 229910000008 nickel(II) carbonate Inorganic materials 0.000 description 2
- ZULUUIKRFGGGTL-UHFFFAOYSA-L nickel(ii) carbonate Chemical compound [Ni+2].[O-]C([O-])=O ZULUUIKRFGGGTL-UHFFFAOYSA-L 0.000 description 2
- KBJMLQFLOWQJNF-UHFFFAOYSA-N nickel(ii) nitrate Chemical compound [Ni+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O KBJMLQFLOWQJNF-UHFFFAOYSA-N 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 238000010008 shearing Methods 0.000 description 2
- 239000007790 solid phase Substances 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- 238000004438 BET method Methods 0.000 description 1
- 241000284156 Clerodendrum quadriloculare Species 0.000 description 1
- 101150113959 Magix gene Proteins 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 229910021586 Nickel(II) chloride Inorganic materials 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 229910001854 alkali hydroxide Inorganic materials 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 238000011088 calibration curve Methods 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000001784 detoxification Methods 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 238000005755 formation reaction Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 229910003455 mixed metal oxide Inorganic materials 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- QMMRZOWCJAIUJA-UHFFFAOYSA-L nickel dichloride Chemical compound Cl[Ni]Cl QMMRZOWCJAIUJA-UHFFFAOYSA-L 0.000 description 1
- RRIWRJBSCGCBID-UHFFFAOYSA-L nickel sulfate hexahydrate Chemical compound O.O.O.O.O.O.[Ni+2].[O-]S([O-])(=O)=O RRIWRJBSCGCBID-UHFFFAOYSA-L 0.000 description 1
- 229940116202 nickel sulfate hexahydrate Drugs 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- -1 sulfuric acid ion Chemical class 0.000 description 1
- 230000002277 temperature effect Effects 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
- 229910001233 yttria-stabilized zirconia Inorganic materials 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
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Abstract
Description
本発明は、酸化ニッケル微粉末の製造方法に関し、特に電子部品材料として好適な硫黄等の不純物品位が低く且つ微細な酸化ニッケル微粉末の製造方法に関する。 The present invention relates to a method for producing nickel oxide fine powder, and more particularly to a method for producing fine nickel oxide fine powder having a low impurity grade such as sulfur suitable as an electronic component material.
酸化ニッケル微粉末は多様な用途に用いられており、例えば、電子部品材料としての用途では、酸化ニッケル微粉末を酸化鉄、酸化亜鉛等の他の材料と混合した後、焼結することによりフェライト部品等を作製することが行われている。このフェライト部品のように複数の材料を混合して焼成することにより複合金属酸化物を製造する場合は、その生成反応は固相の拡散反応で律速されるので、当該材料はより微細であるのが一般的に好ましい。その理由は、微細であれば他の材料との接触確率が高くなると共に粒子の活性が高くなるため、低温で且つ短時間の処理であっても反応が均一に進むからである。従って、上記のような複合金属酸化物の製造では、原料となる粉末の粒径を小さくして微細にすることが効率向上の重要な要件となる。 Nickel oxide fine powders are used in various applications. For example, in applications as electronic component materials, nickel oxide fine powders are mixed with other materials such as iron oxide and zinc oxide and then sintered. Production of parts and the like is performed. When a composite metal oxide is produced by mixing and firing a plurality of materials like this ferrite component, the formation reaction is limited by the diffusion reaction of the solid phase, so that the material is finer Is generally preferred. The reason is that, if fine, the probability of contact with other materials increases and the activity of the particles increases, so that the reaction proceeds uniformly even at low temperature and for a short time. Therefore, in the production of the composite metal oxide as described above, it is an important requirement for improving efficiency to reduce the particle size of the raw material powder to be fine.
近年、フェライト部品はますます高機能化する傾向にあり、加えて酸化ニッケル微粉末の用途は固体酸化物形燃料電池の電極材料等のように、フェライト部品等の電子部品以外にも広がっている。そのため、酸化ニッケル微粉末に含まれる不純物元素のより一層の低減が求められている。不純物元素の中でも特に塩素（Ｃｌ）や硫黄（Ｓ）は、電極に利用されている銀と反応して電極劣化を生じさせたり、焼成炉を腐食させたりすることがあるため、できるだけ低減することが望ましい。また、ナトリウム等のアルカリ金属もフェライト部品の焼成時に焼結を阻害するため、低減することが望ましい。 In recent years, ferrite parts have a tendency to become more sophisticated, and in addition, the use of nickel oxide fine powder has expanded beyond electronic parts such as ferrite parts, such as electrode materials for solid oxide fuel cells. . Therefore, further reduction of the impurity element contained in the nickel oxide fine powder is required. Chlorine (Cl) and sulfur (S), among other impurity elements, should be reduced as much as possible because they may react with the silver used for the electrodes, causing electrode deterioration and corroding the firing furnace. Is desirable. Moreover, it is desirable to reduce alkali metals such as sodium because sintering is inhibited during the firing of ferrite parts.
従来、不純物含有量の低い酸化ニッケル微粉末を製造する方法として、硫酸ニッケル、硝酸ニッケル、炭酸ニッケル、水酸化ニッケル等のニッケル塩類又はニッケルメタル粉を、ロータリーキルン等の転動炉、プッシャー炉等の連続炉、あるいはバーナー炉等のバッチ炉を用いて酸化性雰囲気下で焼成する方法が一般に採用されてきた。例えば、特許文献１には、原料としての硫酸ニッケルに対して、キルンなどを用いて酸化雰囲気中で焙焼温度９５０〜１０００℃未満で焙焼する第１段焙焼と、焙焼温度１０００〜１２００℃で焙焼する第２段焙焼とを行って酸化ニッケル粉末を製造する方法が提案されている。この製造方法によれば、平均粒径が制御され、且つ硫黄品位が５０質量ｐｐｍ以下の酸化ニッケル微粉末が得られると記載されている。 Conventionally, as a method for producing a nickel oxide fine powder having a low impurity content, nickel salts such as nickel sulfate, nickel nitrate, nickel carbonate, nickel hydroxide, or nickel metal powder is used in a rotary kiln or other rolling furnace, pusher furnace, or the like. A method of firing in an oxidizing atmosphere using a continuous furnace or a batch furnace such as a burner furnace has been generally employed. For example, Patent Document 1 discloses a first stage roasting that is performed at a roasting temperature of less than 950 to 1000 ° C. in an oxidizing atmosphere using a kiln or the like with respect to nickel sulfate as a raw material, and a roasting temperature of 1000 to 1000 A method for producing nickel oxide powder by performing second-stage roasting at 1200 ° C. has been proposed. According to this production method, it is described that a nickel oxide fine powder having a controlled average particle size and a sulfur quality of 50 mass ppm or less can be obtained.
また、特許文献２には、４５０〜６００℃の仮焼による脱水工程と、１０００〜１２００℃の焙焼による硫酸ニッケルの分解工程とを明確に分離した酸化ニッケル粉末の製造方法が提案されている。この製造方法によれば、硫黄品位が低く且つ平均粒径が小さい酸化ニッケル微粉末を安定して製造できると記載されている。更に、特許文献３には、横型回転式製造炉を用いて強制的に空気を導入しながら、最高温度を９００〜１２５０℃として焙焼する方法が提案されている。この製造方法によっても、不純物が少なく、硫黄品位が５００質量ｐｐｍ以下の酸化ニッケル粉末が得られると記載されている。 Patent Document 2 proposes a method for producing nickel oxide powder that clearly separates a dehydration step by calcining at 450 to 600 ° C. and a decomposition step of nickel sulfate by roasting at 1000 to 1200 ° C. . According to this production method, it is described that nickel oxide fine powder having a low sulfur quality and a small average particle size can be produced stably. Furthermore, Patent Document 3 proposes a method of roasting at a maximum temperature of 900 to 1250 ° C. while forcibly introducing air using a horizontal rotary manufacturing furnace. It is described that nickel oxide powder with few impurities and a sulfur quality of 500 mass ppm or less can be obtained by this manufacturing method.
上記の乾式法に対して一部湿式法で酸化ニッケル微粉末を製造する方法として、硫酸ニッケルや塩化ニッケル等のニッケル塩を含む水溶液を、水酸化ナトリウム水溶液等のアルカリで中和して水酸化ニッケル粒子を晶析させ、これを焙焼する方法も提案されている。例えば、特許文献４には、ニッケル粉を製造する際の中間物としての水酸化ニッケル粒子を酸化性雰囲気下で加熱処理することによって、多孔質の酸化ニッケル粉末を得る方法が開示されている。この方法は水酸化ニッケルを焙焼する際に陰イオン成分由来のガスの発生がほとんどないため、排ガス処理が不要となるか若しくは簡易な設備でよく、よって低コストでの製造が可能になる。 As a method for producing nickel oxide fine powder by a partial wet method with respect to the dry method described above, an aqueous solution containing a nickel salt such as nickel sulfate or nickel chloride is neutralized with an alkali such as an aqueous sodium hydroxide solution and then hydroxylated. A method for crystallizing nickel particles and baking the nickel particles has also been proposed. For example, Patent Document 4 discloses a method of obtaining porous nickel oxide powder by heat-treating nickel hydroxide particles as an intermediate in producing nickel powder in an oxidizing atmosphere. Since this method hardly generates an anionic component-derived gas when roasting nickel hydroxide, the exhaust gas treatment is not required or simple equipment can be used, so that it can be manufactured at low cost.
上記の特許文献１または特許文献２の方法により不純物品位の低い酸化ニッケル微粉末を得ることができるものの、これら製造方法では熱処理を２回行うため生産性が低下し、コストが高くなるという問題を抱えている。また、特許文献１〜３のいずれの方法においても、硫黄品位を低減するために焙焼温度を高くすると粒径が粗大になり、また粒子を微細にするために焙焼温度を下げると硫黄品位が高くなるという欠点があり、粒径と硫黄品位を同時に最適値に制御することは困難であった。更に、加熱する際に大量のＳＯｘを含むガスが発生し、これを除害処理するために高価な設備が必要になるという問題も抱えている。特許文献４においても酸化ニッケル粉末の硫黄品位を抑えつつその粒径を微細にする技術については開示されていない。 Although nickel oxide fine powder with low impurity quality can be obtained by the method of Patent Document 1 or Patent Document 2 described above, these manufacturing methods have a problem that productivity is lowered and costs are increased because heat treatment is performed twice. I have it. In any of the methods of Patent Documents 1 to 3, when the roasting temperature is increased in order to reduce the sulfur quality, the particle size becomes coarse, and when the roasting temperature is lowered to make the particles finer, the sulfur quality is increased. However, it is difficult to simultaneously control the particle size and sulfur quality to the optimum values. Furthermore, there is a problem that a gas containing a large amount of SOx is generated when heating, and expensive equipment is required to remove the gas. Patent Document 4 does not disclose a technique for reducing the sulfur quality of nickel oxide powder while reducing the particle size.
本発明は、上記した従来技術の問題点に鑑みてなされたものであり、不純物品位、特に硫黄品位が低く且つ微細な酸化ニッケル微粉末の製造方法を提供することを目的としている。 The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a method for producing fine nickel oxide fine powder having low impurity quality, particularly sulfur quality.
本発明者は、上記目的を達成するため、熱処理時に大量の有害ガスが発生するのを抑えるべく、ニッケル塩水溶液の中和により生成される水酸化ニッケルを焙焼して酸化ニッケル微粉末を製造する方法について鋭意研究を重ねた結果、ニッケル塩原料を熱処理して得た酸化ニッケルを解砕した後、アルカリで洗浄することによって、硫黄品位が低く且つ微細な酸化ニッケル微粉末を得ることができることを見出し、本発明を完成するに至った。 In order to achieve the above object, the present inventor manufactured nickel oxide fine powder by roasting nickel hydroxide produced by neutralization of an aqueous nickel salt solution in order to suppress the generation of a large amount of harmful gas during heat treatment. As a result of earnest research on the method to perform, after the nickel oxide obtained by heat-treating the nickel salt raw material is crushed, it is possible to obtain a fine nickel oxide fine powder with low sulfur quality by washing with alkali As a result, the present invention has been completed.
すなわち、本発明の酸化ニッケル微粉末の製造方法は、ニッケル塩を非還元性雰囲気下において熱処理温度８００〜１０００℃で熱処理して酸化ニッケル粉末を生成する熱処理行程と、前記酸化ニッケル粉末を解砕する解砕工程と、前記解砕により得た酸化ニッケル微粉末をアルカリ洗浄する洗浄工程とを有する酸化ニッケル微粉末の製造方法であって、前記アルカリ洗浄が、アルカリ成分を０.１〜１０質量％含有する水溶液に前記酸化ニッケル微粉末を加えてスラリーとし、該スラリーを撹拌することで洗浄を行うことを特徴としている。 That is, the nickel oxide fine powder production method of the present invention includes a heat treatment step in which a nickel salt is heat-treated at a heat treatment temperature of 800 to 1000 ° C. in a non-reducing atmosphere to produce nickel oxide powder, and the nickel oxide powder is crushed. A nickel oxide fine powder production method having a crushing step and a washing step of alkali-washing the nickel oxide fine powder obtained by the crushing, wherein the alkali washing comprises 0.1 to 10 mass of an alkali component. The nickel oxide fine powder is added to an aqueous solution containing 1% to form a slurry, and the slurry is stirred to perform washing.
本発明によれば、不純物品位としての硫黄品位が２００質量ｐｐｍ以下、ナトリウム品位が１００質量ｐｐｍ以下と低く微細な酸化ニッケル微粉末を大量の塩素やＳＯｘガスを発生させることなく簡易に製造することができる。 According to the present invention, a fine nickel oxide fine powder having a sulfur grade as an impurity grade of 200 mass ppm or less and a sodium grade of 100 mass ppm or less is easily produced without generating a large amount of chlorine or SOx gas. Can do.
以下、本発明の実施形態に係る酸化ニッケル微粉末の製造方法について説明する。この酸化ニッケル微粉末の製造方法は、ニッケル塩粒子を非還元性雰囲気下において所定の熱処理温度で熱処理して酸化ニッケル粉末を得る熱処理工程と、この熱処理工程の際に形成され得る酸化ニッケル粉末の焼結体を解砕して酸化ニッケル微粉末を得る解砕工程と、該解砕工程で解砕された酸化ニッケル粉末をアルカリで洗浄する洗浄工程とを有している。この製造方法により、硫黄品位が２００質量ｐｐｍ以下でナトリウム品位が１００質量ｐｐｍ以下の微細な酸化ニッケル微粉末を、除害処理を要する塩素やＳＯｘガスを大量に発生させることなく比較的低コストに作製することができる。以下、これら工程の各々について詳細に説明する。 Hereinafter, the manufacturing method of the nickel oxide fine powder which concerns on embodiment of this invention is demonstrated. This nickel oxide fine powder manufacturing method includes a heat treatment step of obtaining nickel oxide powder by heat-treating nickel salt particles at a predetermined heat treatment temperature in a non-reducing atmosphere, and a nickel oxide powder that can be formed during the heat treatment step. A crushing step of crushing the sintered body to obtain nickel oxide fine powder; and a washing step of washing the nickel oxide powder crushed in the crushing step with an alkali. By this production method, a fine nickel oxide fine powder having a sulfur grade of 200 mass ppm or less and a sodium grade of 100 mass ppm or less can be produced at a relatively low cost without generating a large amount of chlorine or SOx gas that requires detoxification. Can be produced. Hereinafter, each of these steps will be described in detail.
（熱処理工程）
熱処理工程は原料としてのニッケル塩粒子を非還元性雰囲気下において所定の熱処理温度で熱処理することによって酸化ニッケル粉末を生成する工程である。熱処理対象となるニッケル塩粒子は硫酸ニッケル、水酸化ニッケル、炭酸ニッケル、硝酸ニッケルから選ばれる１種以上を用いることができる。これらニッケル塩粒子は、いずれも加熱により熱分解して容易に酸化ニッケル粉末となる。これらのニッケル塩粒子のうち、高純度な原料が安価に入手しやすいという観点から硫酸ニッケルまたは水酸化ニッケルを用いるのが好ましく、特に硫黄成分が低いという観点から水酸化ニッケルがより好ましい。
(Heat treatment process)
The heat treatment step is a step of producing nickel oxide powder by heat-treating nickel salt particles as a raw material at a predetermined heat treatment temperature in a non-reducing atmosphere. As the nickel salt particles to be heat-treated, one or more selected from nickel sulfate, nickel hydroxide, nickel carbonate, and nickel nitrate can be used. All of these nickel salt particles are thermally decomposed by heating to easily become nickel oxide powder. Among these nickel salt particles, it is preferable to use nickel sulfate or nickel hydroxide from the viewpoint that high-purity raw materials are easily available at low cost, and nickel hydroxide is more preferable from the viewpoint that the sulfur component is particularly low.
例えば硫酸ニッケルの熱処理では硫酸ニッケル中の結晶水および硫酸基が脱離し、水酸化ニッケルの熱処理では水酸化ニッケル粒子内の水酸基が脱離する。これにより酸化ニッケル粉末が生成する。その際、粒径の微細化と残存する硫黄などの陰イオン成分の大部分を揮発させることができる。しかし、熱処理温度が８００℃未満では残存する陰イオン成分の揮発が不十分になり、酸化ニッケル粉末中の陰イオン成分、特に硫黄品位を十分に低くすることができなくなる。また、熱処理で生成する酸化ニッケル粉末は、高温での熱処理のため粉末が一部焼結して粒子同士が結合した焼結体が生成し、特に熱処理温度が１０００℃を超えると上記酸化ニッケル粒子同士の焼結が顕著になる。その結果、後工程の解砕工程で解砕を行っても焼結体の結合力が高くなって解砕が困難になり、所望の粒径の酸化ニッケル微粉末が得られにくくなる。従って、熱処理温度は８００〜１０００℃の範囲とし、８５０〜９５０℃の範囲内とするのが好ましい。 For example, the heat treatment of nickel sulfate removes crystal water and sulfate groups in nickel sulfate, and the heat treatment of nickel hydroxide removes hydroxyl groups in the nickel hydroxide particles. This produces nickel oxide powder. At that time, it is possible to volatilize most of the anionic components such as the refinement of the particle size and the remaining sulfur. However, if the heat treatment temperature is less than 800 ° C., volatilization of the remaining anion component becomes insufficient, and the anion component in the nickel oxide powder, in particular, the sulfur quality cannot be sufficiently lowered. In addition, the nickel oxide powder produced by heat treatment produces a sintered body in which the powder is partially sintered due to heat treatment at a high temperature, and the particles are bonded to each other, and particularly when the heat treatment temperature exceeds 1000 ° C. Sintering between the two becomes remarkable. As a result, even if pulverization is performed in the subsequent pulverization step, the bonding strength of the sintered body becomes high and pulverization becomes difficult, making it difficult to obtain nickel oxide fine powder having a desired particle size. Therefore, the heat treatment temperature is in the range of 800 to 1000 ° C, and preferably in the range of 850 to 950 ° C.
上記の熱処理温度及び処理量に応じて熱処理時間を適宜設定することができる。具体的には最終的に得られる酸化ニッケル微粉末の比表面積が３ｍ２／ｇ以上となるように熱処理条件を設定すればよい。後述する解砕により最終的に得られる酸化ニッケル微粉末の比表面積は、熱処理後の酸化ニッケル粉末の比表面積に対して１〜２ｍ２／ｇ程度増加するだけであるので、熱処理後の酸化ニッケル粉末の比表面積で判断して熱処理条件を設定することができる。尚、粒径と比表面積には、下記の式１の関係があるので、比表面積によって粉体がどの程度微細であるか判断することができる。
［式１］
粒径＝６／（密度×比表面積）
但し、上記式１の関係は粒子が真球状であると仮定して導き出されたものであるため、上記式１から得られる粒径と実際の粒径との間にはいくらかの誤差を含むことになるが、比表面積が大きいほど粒径が小さくなることが分かる。
The heat treatment time can be appropriately set according to the heat treatment temperature and the treatment amount. Specifically, the heat treatment conditions may be set so that the specific surface area of the finally obtained nickel oxide fine powder is 3 m 2 / g or more. The specific surface area of the nickel oxide fine powder finally obtained by crushing described later only increases by about 1 to 2 m 2 / g with respect to the specific surface area of the nickel oxide powder after the heat treatment. Judging by the specific surface area of the powder, the heat treatment conditions can be set. Since the particle size and the specific surface area have the relationship of the following formula 1, it can be determined how fine the powder is based on the specific surface area.
[Formula 1]
Particle size = 6 / (density × specific surface area)
However, since the relationship of the above equation 1 is derived on the assumption that the particles are spherical, there is some error between the particle size obtained from the above equation 1 and the actual particle size. However, it can be seen that the larger the specific surface area, the smaller the particle size.
上記のように、熱処理の温度及び時間を調整することにより、容易に酸化ニッケル粉末の比表面積、即ち粒径を調整することができる。熱処理の際の雰囲気は非還元性雰囲気であれば特に限定はないが、経済性を考慮すれば大気雰囲気が好ましい。熱処理には一般的な焙焼炉を使用することができるが、熱処理に伴ってガスが発生するので、このガスを排気するため、十分な流速を持った気流中で熱処理を行うことが好ましい。 As described above, the specific surface area of the nickel oxide powder, that is, the particle size can be easily adjusted by adjusting the temperature and time of the heat treatment. The atmosphere during the heat treatment is not particularly limited as long as it is a non-reducing atmosphere, but an air atmosphere is preferable in consideration of economy. A general roasting furnace can be used for the heat treatment, but a gas is generated along with the heat treatment. Therefore, in order to exhaust the gas, it is preferable to perform the heat treatment in an air flow having a sufficient flow rate.
上記の熱処理対象物であるニッケル塩粒子に水酸化ニッケル粒子を用いる場合は、硫酸ニッケル水溶液をアルカリで中和して沈殿生成することで得られる水酸化ニッケル粒子を用いるのが好ましく、その際の水溶液の濃度及び中和条件等は一般的な技術を適用することができる。最終的に作製される酸化ニッケル微粉末を電子部品用として用いる場合は、硫酸ニッケル中の不純物は１００質量ｐｐｍ未満であることが望ましい。 When nickel hydroxide particles are used for the nickel salt particles that are the heat treatment target, it is preferable to use nickel hydroxide particles obtained by precipitation by neutralizing an aqueous nickel sulfate solution with an alkali. General techniques can be applied to the concentration of the aqueous solution, neutralization conditions, and the like. When the finally produced nickel oxide fine powder is used for electronic parts, it is desirable that the impurities in nickel sulfate be less than 100 mass ppm.
原料となる水酸化ニッケル粒子を上記のように硫酸ニッケル水溶液の中和により生成する場合、硫酸ニッケル水溶液の濃度は特に限定はないが、生産性を考慮すると、ニッケル濃度で５０〜１８０ｇ／Ｌが好ましい。このニッケル濃度が５０ｇ／Ｌ未満では生産性が悪くなる。逆に、ニッケル濃度が１８０ｇ／Ｌを超えると水溶液中の硫酸イオン濃度が高くなりすぎ、生成した水酸化ニッケル粒子中の硫黄品位が高くなるため、最終的に得られる酸化ニッケル微粉末中の不純物品位が十分に低くならない場合がある。 When producing nickel hydroxide particles as a raw material by neutralization of a nickel sulfate aqueous solution as described above, the concentration of the nickel sulfate aqueous solution is not particularly limited, but considering productivity, the nickel concentration is 50 to 180 g / L. preferable. When the nickel concentration is less than 50 g / L, productivity is deteriorated. On the contrary, if the nickel concentration exceeds 180 g / L, the sulfuric acid ion concentration in the aqueous solution becomes too high, and the sulfur quality in the produced nickel hydroxide particles becomes high, so the impurities in the finally obtained nickel oxide fine powder The quality may not be low enough.
上記の中和に用いるアルカリには特に限定はないが、反応液中に残留するニッケルの量を考慮するとアルカリ金属の水酸化物が好ましく、水酸化ナトリウム若しくは水酸化カリウムがより好ましく、コストを考慮すると水酸化ナトリウムが特に好ましい。尚、アルカリは固体又は液体のいずれの形態でニッケル塩水溶液に添加してもよいが、取扱いの容易さから水溶液を用いることが好ましい。 The alkali used for the neutralization is not particularly limited, but considering the amount of nickel remaining in the reaction solution, an alkali metal hydroxide is preferable, sodium hydroxide or potassium hydroxide is more preferable, and cost is considered. Sodium hydroxide is particularly preferred. The alkali may be added to the nickel salt aqueous solution in a solid or liquid form, but it is preferable to use an aqueous solution for ease of handling.
また、均一な特性の水酸化ニッケルを得るためには、反応槽内において十分に撹拌されている液に、予め調製しておいたニッケル塩水溶液である硫酸ニッケル水溶液とアルカリ水溶液とをいわゆるダブルジェット方式で添加して反応液とするのが有効である。即ち、反応槽内に硫酸ニッケル水溶液及びアルカリ水溶液のうちのいずれか一方を入れておき、そこにもう一方を添加して反応液とするのではなく、反応槽内において十分に攪拌されている液中に、好適には該攪拌を継続しながら硫酸ニッケル水溶液とアルカリ水溶液とを同時並行的に且つ連続的に乱流状態で添加して反応液とする方式が有効である。その際、反応槽内に予め入れておく液は、純水にアルカリを添加し、所定のｐＨに調整したものが好ましい。 In addition, in order to obtain nickel hydroxide having uniform characteristics, a nickel sulfate aqueous solution and an alkaline aqueous solution, which are nickel salt aqueous solutions prepared in advance, are added to a sufficiently stirred liquid in a reaction vessel. It is effective to add it as a reaction solution in a system. That is, a liquid that is sufficiently stirred in the reaction tank, not one of the nickel sulfate aqueous solution and the alkaline aqueous solution is put in the reaction tank and the other is added to the reaction liquid. In particular, it is effective to add a nickel sulfate aqueous solution and an alkaline aqueous solution simultaneously and continuously in a turbulent state while continuing the stirring to make a reaction solution. In that case, the liquid previously put in the reaction tank is preferably adjusted to a predetermined pH by adding alkali to pure water.
上記の反応槽内の反応液は、中和反応時のｐＨが８.３〜９.０の範囲内に調整されることが好ましく、この範囲内でｐＨがほぼ一定に維持されていることが特に好ましい。このｐＨが８.３より低いと、水酸化ニッケル粒子中に残存する硫酸イオンなどの陰イオン成分の濃度が増大し、熱処理工程で焼成する際に、大量のＳＯｘが発生することがあるため好ましくない。逆に、このｐＨが９.０より高くなると、得られる水酸化ニッケル粒子が微細になりすぎ、この水酸化ニッケルを含むスラリーの濾過が困難になることがある。また、後工程の熱処理で焼結が進みすぎ、最終的に酸化ニッケル微粉末を得ることが困難になることがある。尚、ｐＨ９.０以下にすると水溶液中に僅かにニッケル成分が残存することがあるが、その場合は、中和反応の終了後に水酸化ニッケルスラリーのｐＨを１０程度まで上げて水溶液中のニッケル成分を水酸化ニッケルに析出させることが好ましい。 The reaction liquid in the reaction tank is preferably adjusted to a pH of 8.3 to 9.0 during the neutralization reaction, and the pH is maintained substantially constant within this range. Particularly preferred. When this pH is lower than 8.3, the concentration of anion components such as sulfate ions remaining in the nickel hydroxide particles is increased, and a large amount of SOx may be generated when firing in the heat treatment step. Absent. Conversely, when the pH is higher than 9.0, the resulting nickel hydroxide particles become too fine, and it may be difficult to filter the slurry containing the nickel hydroxide. In addition, sintering may proceed excessively in the subsequent heat treatment, and it may be difficult to finally obtain nickel oxide fine powder. When the pH is 9.0 or less, a slight amount of nickel component may remain in the aqueous solution. In this case, the pH of the nickel hydroxide slurry is increased to about 10 after the completion of the neutralization reaction. Is preferably deposited on nickel hydroxide.
中和反応時の液温は、一般的な中和反応時の温度で特に問題はなく、室温で行うことも可能であるが、水酸化ニッケル粒子を十分に成長させるために５０〜７０℃に調整するのが好ましい。水酸化ニッケル粒子を十分に成長させることで、水酸化ニッケル粒子中への硫黄の巻き込みを抑制し、最終的な酸化ニッケル微粉末の硫黄品位を低減させることができる。この液温が５０℃未満では水酸化ニッケル粒子の成長が不十分になって、水酸化ニッケル粒子中への硫黄の巻き込み多くなるおそれがある。逆に、液温が７０℃を超えると、水の蒸発が顕著になり、水溶液中の硫黄濃度が高くなるため、生成した水酸化ニッケル粒子中の硫黄品位が高くなることがある。 The liquid temperature during the neutralization reaction is not particularly limited as the temperature during the general neutralization reaction, and can be carried out at room temperature. However, in order to sufficiently grow nickel hydroxide particles, the temperature is set to 50 to 70 ° C. It is preferable to adjust. By sufficiently growing the nickel hydroxide particles, it is possible to suppress the inclusion of sulfur into the nickel hydroxide particles and to reduce the sulfur quality of the final nickel oxide fine powder. If this liquid temperature is less than 50 ° C., the growth of nickel hydroxide particles becomes insufficient, and there is a risk that sulfur will be entrained in the nickel hydroxide particles. On the contrary, when the liquid temperature exceeds 70 ° C., the evaporation of water becomes remarkable, and the sulfur concentration in the aqueous solution becomes high, so that the sulfur quality in the produced nickel hydroxide particles may be high.
上記中和反応の終了後、析出した水酸化ニッケル粒子を含むスラリーを例えば濾過により固液分離して該水酸化ニッケル粒子を濾過ケーキの形態で回収する。回収した濾過ケーキは、次の熱処理工程で処理する前に洗浄することが好ましい。洗浄はレパルプ洗浄とすることが好ましく、その洗浄に用いる洗浄液としては水が好ましく、純水が特に好ましい。洗浄時の水酸化ニッケルと水との混合割合は、ニッケル塩に残留する陰イオンを十分に低減でき且つ水酸化ニッケル粒子を良好に分散させることができる量とするのが好ましい。特に硫酸ニッケルを原料とする場合は硫酸イオンが十分に除去でき且つ良好に分散できる混合割合とすればよい。具体的には、水酸化ニッケル粒子５０〜１５０ｇに対して水１Ｌを混合するのが好ましく、水酸化ニッケル粒子１００ｇ程度に対して水１Ｌを混合するのがより好ましい。 After completion of the neutralization reaction, the slurry containing the precipitated nickel hydroxide particles is solid-liquid separated by, for example, filtration, and the nickel hydroxide particles are recovered in the form of a filter cake. The recovered filter cake is preferably washed before being processed in the next heat treatment step. The washing is preferably repulp washing, and the washing liquid used for the washing is preferably water, and particularly preferably pure water. The mixing ratio of nickel hydroxide and water at the time of washing is preferably set to an amount that can sufficiently reduce the anions remaining in the nickel salt and can disperse the nickel hydroxide particles well. In particular, when nickel sulfate is used as a raw material, the mixing ratio may be such that sulfate ions can be sufficiently removed and dispersed well. Specifically, 1 L of water is preferably mixed with 50 to 150 g of nickel hydroxide particles, and 1 L of water is more preferably mixed with about 100 g of nickel hydroxide particles.
上記濾過ケーキの洗浄時間については、使用する洗浄液の種類や量、残留陰イオンの種類等の処理条件に応じて適宜定めることができ、残留陰イオンが十分に低減可能な時間とすればよい。残留陰イオンを十分に低減可能な洗浄処理条件とすることにより、酸化ニッケルの微細化効果も十分に得られる。洗浄後は濾過などの固液分離手段で脱水し、乾燥器で乾燥するのが好ましい。尚、１回の洗浄で陰イオンを十分に低減することができない場合は、複数回繰り返して洗浄することが好ましい。例えば洗浄液に純水を用いる場合は、洗浄後の洗浄液の導電率を測定して所定の導電率以下となるまで洗浄と脱水を繰り返すことで、硫酸イオン等の陰イオンを十分に除去することができる。 The washing time of the filter cake can be appropriately determined according to the processing conditions such as the type and amount of the cleaning liquid to be used, the type of residual anion, etc., and may be a time that can sufficiently reduce the residual anion. By making the cleaning conditions under which residual anions can be sufficiently reduced, the effect of miniaturizing nickel oxide can be sufficiently obtained. After washing, it is preferable to dehydrate with a solid-liquid separation means such as filtration and dry with a drier. In addition, when the anion cannot be sufficiently reduced by one washing, it is preferable to repeat the washing a plurality of times. For example, when pure water is used as the cleaning liquid, it is possible to sufficiently remove anions such as sulfate ions by measuring the conductivity of the cleaning liquid after cleaning and repeating the cleaning and dehydration until it becomes a predetermined conductivity or less. it can.
（解砕工程）
熱処理工程の次に行われる解砕工程は、上記熱処理工程の熱処理による酸化焙焼の際に形成され得る酸化ニッケル粒子の焼結体を解砕して微細化する工程である。一般的には、解砕方法にはビーズミルやボールミル等の解砕メディアを用いる方法のほか、解砕メディアを用いずに流体エネルギーにより解砕するジェットミル等を用いる方法があるが、本発明の実施形態の製造方法においては、解砕メディアを用いない後者の解砕方法を採用することが好ましい。なぜなら、解砕メディアを用いると解砕自体は容易となるものの、ジルコニア等の解砕メディアを構成している成分が不純物として混入するおそれがあるからである。
(Crushing process)
The crushing step performed after the heat treatment step is a step of crushing and refining a sintered body of nickel oxide particles that can be formed during the oxidation roasting by the heat treatment in the heat treatment step. In general, the crushing method includes a method using a crushing media such as a bead mill and a ball mill, and a method using a jet mill that crushes by fluid energy without using a crushing media. In the manufacturing method of the embodiment, it is preferable to employ the latter crushing method that does not use crushing media. This is because, when the crushing media is used, crushing itself is easy, but components constituting the crushing media such as zirconia may be mixed as impurities.
不純物としてジルコニウムのみが問題になるのであれば、ジルコニウムを含有しないアルミナ等の解砕メディアを用いて解砕すればよいが、この場合であっても解砕メディアの摩耗等により酸化ニッケル粒子に不純物が混入することになるので、結果的に低不純物品位の酸化ニッケル微粉末を得ることができなくなるので好ましくない。特に、解砕メディアがイットリア安定化ジルコニアに代表されるジルコニウムを含有しない場合は、強度や耐摩耗性が不十分になり、不純物の含有率が多くなるので、この観点からも解砕メディアを用いない解砕方法が望ましい。 If only zirconium is a problem as an impurity, it may be crushed using a crushed media such as alumina that does not contain zirconium. As a result, nickel oxide fine powder with low impurity quality cannot be obtained, which is not preferable. In particular, when the crushing media does not contain zirconium typified by yttria-stabilized zirconia, the strength and wear resistance are insufficient, and the content of impurities increases. No crushing method is desirable.
解砕メディアを用いない解砕方法としては、ガス（気体）や溶媒（液体）を用いて粉体の粒子同士を衝突させる方法や、液体などの溶媒により粉体にせん断力をかける方法、溶媒のキャビテーションによる衝撃力を用いる方法等がある。粉体の粒子同士を衝突させる解砕装置としては、例えば、乾式ジェットミルや湿式ジェットミルがあり、具体的には前者にはナノグラインディングミル（登録商標）やクロスジェットミル（登録商標）、後者にはアルティマイザー（登録商標）やスターバースト（登録商標）等を挙げることができる。また、溶媒によりせん断力を与える解砕装置としては、例えば、ナノマイザー（登録商標）等があり、溶媒のキャビテーションによる衝撃力を用いた解砕装置としては、例えば、ナノメーカー（登録商標）等を挙げることができる。 Crushing methods that do not use crushing media include a method in which particles of a powder collide with each other using a gas (gas) or a solvent (liquid), a method in which a shearing force is applied to the powder with a solvent such as a liquid, and a solvent. There is a method using an impact force caused by cavitation. Examples of the crushing device that collides the particles of the powder include a dry jet mill and a wet jet mill. Specifically, the former includes a nano grinding mill (registered trademark), a cross jet mill (registered trademark), Examples of the latter include Optimizer (registered trademark) and Starburst (registered trademark). In addition, as a crushing device that gives a shearing force with a solvent, for example, there is a nanomizer (registered trademark), and as a crushing device using an impact force due to cavitation of a solvent, for example, a nanomaker (registered trademark) Can be mentioned.
上記解砕方法のうち、粉体の粒子同士を衝突させる方法が、不純物混入の虞が少なく、比較的大きな解砕力が得られることから特に好ましい。更に、粒子同士を衝突させることにより、酸化ニッケル粒子の表面近傍の陰イオン成分が含まれる層が剥離して、後工程の洗浄工程において残留陰イオン成分の更なる低減が可能となる。このように、解砕メディアを用いることなく解砕を行うことにより、解砕メディアからの不純物、特にジルコニウムの混入が実質的になく、塩素などの不純物品位が低く、且つ粒径が微細な酸化ニッケル微粒粉を得ることが可能となる。 Among the above-mentioned pulverization methods, a method of causing powder particles to collide with each other is particularly preferable because there is little possibility of mixing impurities and a relatively large pulverization force can be obtained. Further, by causing the particles to collide with each other, the layer containing the anion component in the vicinity of the surface of the nickel oxide particles is peeled off, and the residual anion component can be further reduced in the subsequent cleaning step. In this way, by crushing without using a crushing media, impurities from the crushing media, in particular zirconium, are not substantially mixed, and the quality of impurities such as chlorine is low, and the particle size is fine. It becomes possible to obtain nickel fine powder.
解砕条件については特に限定はなく、いずれの解砕方法の場合も通常の条件の範囲内での調整により容易に目的とする不純物品位と粒度分布を有する酸化ニッケル微粉末を得ることができる。これにより、フェライト部品などの電子部品材料として好適な分散性に優れた酸化ニッケル微粉末を得ることができる。 There are no particular limitations on the crushing conditions, and in any crushing method, fine nickel oxide powder having the desired impurity grade and particle size distribution can be easily obtained by adjustment within the range of normal conditions. Thereby, the nickel oxide fine powder excellent in the dispersibility suitable as electronic component materials, such as a ferrite component, can be obtained.
（洗浄工程）
洗浄工程は、上記解砕工程での解砕により得られた酸化ニッケル粉末をアルカリ水溶液でスラリー化した後、撹拌することで洗浄を行う工程である。これにより酸化ニッケル粉末の硫黄分を顕著に低減することが可能になる。前述したように、熱処理工程における熱処理では、ニッケル塩粒子中の陰イオン成分を離脱させて酸化ニッケル粉末とする際、粒径の微細化と共に、抑制されているものの高温の影響で酸化ニッケル粉末の焼結がある程度進行する。上記の解砕工程では、この酸化ニッケル粉末に含まれ得る焼結体を破壊し、最終的に微細な酸化ニッケル微粉末とする。この酸化ニッケル粉末の解砕では、酸化ニッケルの粒子に新生面が現れるので、この酸化ニッケル粉末をアルカリ水溶液中で撹拌することによって残留している硫酸などの陰イオン成分を効果的に除去することができる。
(Washing process)
The washing step is a step in which the nickel oxide powder obtained by crushing in the crushing step is slurried with an aqueous alkaline solution and then washed by stirring. This makes it possible to significantly reduce the sulfur content of the nickel oxide powder. As described above, in the heat treatment in the heat treatment process, when the anion component in the nickel salt particles is released to form a nickel oxide powder, the particle size is reduced and the nickel oxide powder is affected by the high temperature effect although it is suppressed. Sintering proceeds to some extent. In the above crushing step, the sintered body that can be contained in the nickel oxide powder is destroyed to finally form a fine nickel oxide fine powder. In the pulverization of the nickel oxide powder, a new surface appears in the nickel oxide particles. By stirring the nickel oxide powder in an alkaline aqueous solution, the remaining anion components such as sulfuric acid can be effectively removed. it can.
一般的に、陰イオン成分は酸化ニッケル粉末を構成する各粒子の表面近傍に多く存在すると考えられる。従って、熱処理後の酸化ニッケル粉末を洗浄液でスラリー化して撹拌することにより、該粒子表面に存在する陰イオン成分の除去は可能であるが、粒子間の焼結部に存在する陰イオン成分はスラリーの溶液と接触することができない。従って、熱処理後の酸化ニッケル粉末をスラリー化して撹拌するのみでは、硫酸などの陰イオン成分を十分に除去することは不可能である。しかし、本発明の実施形態の方法では、上記したように熱処理後の酸化ニッケル粉末を解砕処理してからスラリー状態にして洗浄するので、硫酸などの陰イオン成分を十分に除去することが可能となる。 Generally, it is considered that a large amount of anionic components are present in the vicinity of the surface of each particle constituting the nickel oxide powder. Therefore, it is possible to remove the anion component present on the particle surface by slurrying and stirring the nickel oxide powder after the heat treatment with a cleaning solution, but the anion component present in the sintered portion between the particles is a slurry. In contact with other solutions. Therefore, it is impossible to sufficiently remove anionic components such as sulfuric acid only by slurrying and stirring the nickel oxide powder after heat treatment. However, in the method of the embodiment of the present invention, as described above, the nickel oxide powder after the heat treatment is crushed and then washed in a slurry state, so that anion components such as sulfuric acid can be sufficiently removed. It becomes.
上記の酸化ニッケル粉末のスラリー化に用いる溶液は、酸化ニッケル粉末に含有する陰イオン成分を溶解できるものであれば特に限定はないが、含有する陰イオン成分が水溶性であることからアルカリ水溶液を用いることが好ましく、不純物の混入を極力少なくするため、このアルカリ水溶液の溶媒には純水を用いることが更に好ましい。洗浄時のスラリー濃度には特に限定はないが、１００〜３００ｇ／Ｌ程度であれば効率よく洗浄できるので好ましい。尚、上記解砕工程後の酸化ニッケルに残留する硫酸などの陰イオン成分の量は微量であるため、上記のスラリー濃度であれば十分に陰イオン成分を低減させることができる。 The solution used for slurrying the nickel oxide powder is not particularly limited as long as it can dissolve the anion component contained in the nickel oxide powder. However, since the contained anion component is water-soluble, an alkaline aqueous solution is used. It is preferable to use it, and it is more preferable to use pure water as the solvent of the alkaline aqueous solution in order to minimize the contamination of impurities. The slurry concentration at the time of washing is not particularly limited, but is preferably about 100 to 300 g / L because it can be washed efficiently. In addition, since the quantity of anion components, such as a sulfuric acid which remains in the nickel oxide after the said crushing process, is a trace amount, if it is said slurry density | concentration, an anion component can fully be reduced.
洗浄液のアルカリ水溶液に含有させるアルカリは水酸化アルカリとするのが好ましく、水酸化ナトリウム及び水酸化カリウムのうちの少なくとも一方とするのがより好ましく、コストや入手の容易さから水酸化ナトリウムが特に好ましい。アルカリ水溶液中のアルカリ濃度は０.１質量％以上とするのが好ましい。アルカリ濃度が０.１質量％未満では、硫酸などの陰イオン成分を低減させる効果が水による洗浄の場合と大差なく、十分な洗浄効果が得られなくなるおそれがある。アルカリ濃度は高くすることにより陰イオン成分を低減させる効果が向上するので、上限は特に限定がないが、１０質量％を超えると更なる効果の向上は見られなくなるので、１０質量％をアルカリ濃度の上限とするのが好ましい。 The alkali contained in the alkaline aqueous solution of the cleaning liquid is preferably alkali hydroxide, more preferably at least one of sodium hydroxide and potassium hydroxide, and sodium hydroxide is particularly preferable from the viewpoint of cost and availability. . The alkali concentration in the alkaline aqueous solution is preferably 0.1% by mass or more. If the alkali concentration is less than 0.1% by mass, the effect of reducing anionic components such as sulfuric acid is not much different from that of washing with water, and a sufficient washing effect may not be obtained. Since the effect of reducing the anion component is improved by increasing the alkali concentration, the upper limit is not particularly limited, but if the amount exceeds 10% by mass, further improvement in the effect is not observed, so 10% by mass is added to the alkali concentration The upper limit is preferably set.
アルカリ水溶液で洗浄する際の温度は室温でもかまわないが、加温することにより硫酸などの陰イオン成分を低減させる効果が向上する。しかしながら温度を高くしていくと水の蒸発量が多くなり、アルカリ成分の濃度管理が困難となるので、温度範囲としては２０〜１００℃が好ましく、３０〜９０℃とするのがより好ましく、４０〜８０℃がさらに好ましい。 The temperature at the time of washing with the alkaline aqueous solution may be room temperature, but the effect of reducing anion components such as sulfuric acid is improved by heating. However, as the temperature is increased, the amount of water evaporation increases and it becomes difficult to control the concentration of the alkali component. Therefore, the temperature range is preferably 20 to 100 ° C, more preferably 30 to 90 ° C, and 40 More preferred is -80 ° C.
上記のアルカリ水溶液による酸化ニッケル粉末のスラリーを撹拌しながら洗浄する時間は、１５分以上とするのが好ましい。この洗浄時間が１５分未満では、硫酸などの陰イオンを低減する効果が十分ではないことがある。上記のように撹拌しながら洗浄する場合は洗浄時間が長くなるほど陰イオンを低減する効果が向上するが、１０時間を超えると更なる効果が見られなくなり、かえって生産性が低下するので洗浄時間の上限は１０時間とするのが好ましい。 The time for washing the nickel oxide powder slurry with the aqueous alkali solution while stirring is preferably 15 minutes or more. If the washing time is less than 15 minutes, the effect of reducing anions such as sulfuric acid may not be sufficient. When washing with stirring as described above, the effect of reducing anions improves as the washing time becomes longer. However, when the washing time exceeds 10 hours, no further effect is seen, and the productivity is reduced. The upper limit is preferably 10 hours.
上記のアルカリ水溶液による洗浄後は、濾過、遠心分離などの固液分離を行って脱液し、残った固形分を水でリンス洗浄するのが好ましい。これにより、酸化ニッケル粉末に残留しているアルカリ成分を除去することができる。このリンス洗浄に用いる水は純水であるのがより好ましい。リンス洗浄後は、濾過等の固液分離により脱水し、更に乾燥器で乾燥させることで酸化ニッケル微粉末が得られる。 After washing with the above alkaline aqueous solution, it is preferable to carry out solid-liquid separation such as filtration and centrifugation to remove the liquid, and rinse the remaining solid with water. Thereby, the alkaline component remaining in the nickel oxide powder can be removed. The water used for the rinse cleaning is more preferably pure water. After rinsing, the nickel oxide fine powder is obtained by dehydrating by solid-liquid separation such as filtration and further drying with a drier.
上記したように、本発明の実施形態に係る酸化ニッケル微粉末の製造方法は、２段焙焼を要しないので製造コストを抑えることができる。また、この製造方法は、湿式法により製造した水酸化ニッケルを熱処理するものであるため、有害なＳＯｘが大量発生することがない。従って、これを除害処理するための高価な設備も不要となり製造コストを低く抑えることができる。 As described above, since the nickel oxide fine powder manufacturing method according to the embodiment of the present invention does not require two-stage roasting, the manufacturing cost can be reduced. Moreover, since this manufacturing method heat-processes the nickel hydroxide manufactured by the wet method, harmful SOx does not generate in large quantities. Therefore, an expensive facility for removing this is not necessary, and the manufacturing cost can be kept low.
（酸化ニッケル微粉末の物性）
以上説明した一連の工程で作製される酸化ニッケル微粉末は不純物品位が低いうえ、比表面積が大きいので前述した式１から分かるように粒径が微細である。具体的には、硫黄品位が２００質量ｐｐｍ以下、ナトリウム品位が１００質量ｐｐｍ以下である。また、比表面積は３ｍ２／ｇ以上であり、その上限は１０ｍ２／ｇ程度である。このような物性を有する酸化ニッケル微粉末は電子部品用の材料として好適である。
(Physical properties of fine nickel oxide powder)
The nickel oxide fine powder produced by the series of steps described above has a low impurity quality and a large specific surface area, so that the particle size is fine as can be seen from Equation 1 described above. Specifically, the sulfur quality is 200 mass ppm or less, and the sodium quality is 100 mass ppm or less. Moreover, a specific surface area is 3 m < 2 > / g or more, and the upper limit is about 10 m < 2 > / g. The nickel oxide fine powder having such physical properties is suitable as a material for electronic parts.
尚、上記した本発明の実施形態の酸化ニッケル微粉末の製造方法においては、マグネシウム等の第２族元素を添加する工程を含まないので、これらの元素が不純物として含まれることは実質的にない。更に解砕メディアを用いることなく解砕を行うので、ジルコニアの混入を防止することができる。従って、ジルコニア品位及び第２族元素品位を、いずれも３０質量ｐｐｍ以下にすることができる。 In addition, in the manufacturing method of the nickel oxide fine powder of embodiment mentioned above, since the process of adding Group 2 elements, such as magnesium, is not included, these elements are not substantially contained as an impurity. . Furthermore, since crushing is performed without using a crushing medium, mixing of zirconia can be prevented. Therefore, both the zirconia quality and the Group 2 element quality can be 30 ppm by mass or less.
更に、本発明の実施形態の製造方法により作製される酸化ニッケル微粉末は、レーザー散乱法で測定したＤ５０（粒度分布曲線における粒子量の体積積算５０％での粒径）を好ましくは１.０μｍ以下に、より好ましくは０.６μｍ以下にすることができる。尚、電子部品等の製造時に、酸化ニッケル粉末を他の材料と混合する場合は、この混合の際に解砕が生じることがあり、これによりレーザー散乱法で測定したＤ５０が小さくなると考えられる。但し、この解砕によって比表面積が大きくなる可能性は低いため、酸化ニッケル微粉末の比表面積を粒径の大きさを判断する主たる指標とするのが好ましい。すなわち、酸化ニッケル微粉末の比表面積が上記の範囲内にあるか否か判断することでより確実かつ安定的に品質を確保することが可能になる。 Furthermore, the nickel oxide fine powder produced by the production method according to the embodiment of the present invention preferably has a D50 (particle diameter of 50% by volume of particle amount in the particle size distribution curve) measured by a laser scattering method, preferably 1.0 μm. In the following, it can be more preferably 0.6 μm or less. In addition, when nickel oxide powder is mixed with other materials at the time of manufacturing electronic parts and the like, crushing may occur during the mixing, and this is considered to reduce D50 measured by the laser scattering method. However, since it is unlikely that the specific surface area will increase due to this crushing, the specific surface area of the nickel oxide fine powder is preferably used as the main index for determining the size of the particle size. That is, it is possible to ensure quality more reliably and stably by determining whether or not the specific surface area of the nickel oxide fine powder is within the above range.
また、本発明の実施形態の製造方法で得られる酸化ニッケル微粉末は、焼結開始温度を低くできるという特徴を有している。電子部品等の製造において、酸化ニッケル微粉末を他の材料と混合して複合金属酸化物を製造する場合は、加熱による固相の拡散反応を利用するので、低い焼結開始温度を有することはこの反応を促進する方向に働き有利である。このように焼結開始温度を低くできる理由としては、酸化ニッケル微粉末、特に酸化ニッケル微粉末粒子表面や界面に存在する硫酸塩成分が、洗浄により低減され、酸化ニッケル微粉末粒子同士の焼結を阻害しなくなることによるものと考えられる。尚、焼結開始温度は、例えば酸化ニッケル微粉末を加圧してプレス体とし、そのプレス体を熱機械分析（ＴＭＡ）装置で一定速度で昇温させながら収縮率を測定した熱収縮挙動のグラフから求めることができる。具体的には、図１に示す通り、収縮開始温度は、熱収縮を始める前のプレス体の収縮率曲線の直線部分の延長線と、熱収縮の開始後において温度に対する収縮率が一定となった時の収縮率曲線の直線部分の延長線とが交わる点の温度から求めることができる。 Further, the nickel oxide fine powder obtained by the production method of the embodiment of the present invention has a feature that the sintering start temperature can be lowered. In the production of electronic parts, etc., when producing a mixed metal oxide by mixing nickel oxide fine powder with other materials, it uses a solid phase diffusion reaction by heating, so it has a low sintering start temperature. It works in the direction of promoting this reaction and is advantageous. The reason why the sintering start temperature can be lowered in this way is that nickel oxide fine powder, especially the sulfate component present on the nickel oxide fine powder particle surface and interface is reduced by washing, and the nickel oxide fine powder particles are sintered together. This is thought to be due to the fact that it no longer obstructs. The sintering start temperature is, for example, a graph of heat shrinkage behavior in which a nickel oxide fine powder is pressed into a press body, and the press body is heated at a constant speed with a thermomechanical analysis (TMA) apparatus and the shrinkage rate is measured. Can be obtained from Specifically, as shown in FIG. 1, the shrinkage start temperature is an extension of the linear portion of the shrinkage curve of the press body before starting heat shrinkage, and the shrinkage rate with respect to temperature becomes constant after the start of heat shrinkage. It can be obtained from the temperature at the point where the extended line of the straight line portion of the shrinkage rate curve at the time intersects.
以下、本発明実施例及び比較例の製造方法を用いて酸化ニッケル微粉末を作製し、それらの硫黄品位、ナトリウム品位、比表面積、Ｄ５０、及び収縮開始温度について評価した。尚、上記の硫黄品位の分析は、蛍光Ｘ線定量分析装置（ＰＡＮａｌｙｔｉｃａｌ社製 Ｍａｇｉｘ）を用いて検量線法で評価することによって行った。また、ナトリウム品位の分析は、硝酸に溶解した後、原子吸光光度計（日立ハイテク社製 Ｚ−２３００）によって行った。酸化ニッケル微粉末の粒径は、レーザー散乱法により測定し、その粒度分布から体積積算５０％での粒径Ｄ５０を求めた。比表面積の分析は、窒素ガス吸着によるＢＥＴ法により求めた。 Hereinafter, nickel oxide fine powders were produced using the production methods of the examples of the present invention and comparative examples, and their sulfur quality, sodium quality, specific surface area, D50, and shrinkage start temperature were evaluated. The sulfur quality was analyzed by evaluating with a calibration curve method using a fluorescent X-ray quantitative analyzer (Magix manufactured by PANalytical). Further, the sodium quality was analyzed with an atomic absorption photometer (Z-2300, manufactured by Hitachi High-Tech) after being dissolved in nitric acid. The particle diameter of the nickel oxide fine powder was measured by a laser scattering method, and the particle diameter D50 with a volume integration of 50% was determined from the particle size distribution. The specific surface area was analyzed by the BET method using nitrogen gas adsorption.
また、酸化ニッケル微粉末をプレス機で１００ＭＰａの荷重をかけて円柱状のプレス体とし、このプレス体を熱機械分析（ＴＭＡ）装置（ＢＲＵＫＥＲ Ｃｏｒｐｏｒａｔｉｏｎ製、ＴＭＡ４０００ＳＡ）を用いて昇温速度１０℃／分で室温から１２００℃まで加熱し、プレス体にかける荷重を１０ｍＮとして熱収縮挙動を測定した。得られた熱収縮挙動のグラフより収縮開始温度を求めた。 Further, the nickel oxide fine powder is made into a cylindrical press body by applying a load of 100 MPa with a press machine, and this press body is heated at a rate of 10 ° C./temperature using a thermomechanical analysis (TMA) apparatus (manufactured by BRUKER Corporation, TMA4000SA). The heat shrinkage behavior was measured by heating from room temperature to 1200 ° C. in minutes and setting the load applied to the pressed body to 10 mN. The shrinkage start temperature was determined from the obtained graph of heat shrinkage behavior.
［実施例１］
硫酸ニッケル六水和物（住友金属鉱山株式会社製、商品名ファインエメラルド）１ｋｇを３００ｍｍ角のムライト製匣鉢に入れた。これをマッフル炉（入江株式会社製、内寸：３００ｍｍ×５００ｍｍ×２００ｍｍ）に装入し、その内部に乾燥空気を１０Ｌ／分で流しながら１０℃／分の昇温速度で昇温し、９００℃に到達したときにそのまま２時間保持した（熱処理工程）。この熱処理工程によって生成した酸化ニッケル粉末を乾式ジェットミルであるナノグラインディングミル（徳寿工作所製）にてプッシャーノズル圧力１.０ＭＰａ、グラインディング圧力０.９ＭＰａで粉砕して酸化ニッケル微粉末を得た（解砕工程）。得られた酸化ニッケル微粉末を一部サンプリングして不純物品位を分析し、またＤ５０及び収縮開始温度を測定した。その結果、硫黄品位は３８０質量ｐｐｍ、ナトリウム品位は１０質量ｐｐｍ未満、比表面積は３.３ｍ２／ｇ、Ｄ５０は０.５μｍ、プレス体の収縮開始温度は９００℃であった。
[Example 1]
1 kg of nickel sulfate hexahydrate (manufactured by Sumitomo Metal Mining Co., Ltd., trade name Fine Emerald) was placed in a 300 mm square mullite bowl. This was charged into a muffle furnace (Irie Co., Ltd., internal dimensions: 300 mm × 500 mm × 200 mm), and heated at a rate of temperature increase of 10 ° C./min while flowing dry air at 10 L / min. When it reached 0 ° C., it was kept for 2 hours (heat treatment step). Nickel oxide powder produced by this heat treatment step is pulverized with a nano-grinding mill (manufactured by Deoksugaku Kogyo), which is a dry jet mill, at a pusher nozzle pressure of 1.0 MPa and a grinding pressure of 0.9 MPa to obtain a fine nickel oxide powder. (Cracking step). Part of the obtained nickel oxide fine powder was sampled to analyze the impurity quality, and D50 and shrinkage start temperature were measured. As a result, the sulfur quality was 380 mass ppm, the sodium quality was less than 10 mass ppm, the specific surface area was 3.3 m 2 / g, D50 was 0.5 μm, and the shrinkage start temperature of the pressed body was 900 ° C.
次に、上記の解砕工程で得た酸化ニッケル微粉末から１００ｇずつ８サンプル分取し、それらの各々を洗浄溶液として予め調製しておいた濃度０.５質量％の水酸化ナトリウム水溶液中１リットルに分散させてスラリーとし、これを撹拌することで洗浄した。その際、これら８つのスラリーのうち４つは室温（２５℃）のまま撹拌洗浄し、残る４つは６０℃に加温しながら撹拌洗浄した。また、上記の室温及び加温の場合の各々において洗浄時間の影響を調べるため、４つのスラリーの洗浄時間はそれぞれ１、３、５及び１０時間にした。 Next, 8 samples of 100 g each of the nickel oxide fine powder obtained in the above crushing step were collected, and each of them was prepared in a sodium hydroxide aqueous solution having a concentration of 0.5 mass% prepared in advance as a washing solution. The slurry was dispersed in 1 liter to form a slurry, which was washed by stirring. At that time, four of these eight slurries were stirred and washed at room temperature (25 ° C.), and the remaining four were washed with stirring while warming to 60 ° C. Moreover, in order to investigate the influence of the washing time in each of the above room temperature and heating cases, the washing times of the four slurries were set to 1, 3, 5 and 10 hours, respectively.
この水酸化ナトリウム水溶液による撹拌洗浄後、各々ヌッチェに載置した濾紙でスラリーを固液分離した後、この濾紙上に残った固形分にそのまま純水を供給することで酸化ニッケル粉末に残留しているアルカリ成分をリンス洗浄した。得られた濾過ケーキを１１０℃の大気中にて１２時間乾燥し、酸化ニッケル微粉末を得た（洗浄工程）。このようにして得た試料１〜８の酸化ニッケル微粉末の不純物品位を分析し、また、Ｄ５０及び収縮開始温度を測定した。その結果を下記表１に示す。 After stirring and washing with this aqueous sodium hydroxide solution, the slurry was separated into solid and liquid with each filter paper placed on Nutsche, and pure water was supplied as it was to the solid content remaining on this filter paper to remain in the nickel oxide powder. The alkaline component is rinse-washed. The obtained filter cake was dried in the atmosphere at 110 ° C. for 12 hours to obtain fine nickel oxide powder (cleaning step). Impurity grades of the nickel oxide fine powders of Samples 1 to 8 thus obtained were analyzed, and D50 and shrinkage start temperature were measured. The results are shown in Table 1 below.
上記表１から分かるように、硫黄（Ｓ）品位は１００質量ｐｐｍ〜１８０質量ｐｐｍの範囲内にあり、いずれも規定値の２００質量ｐｐｍ以下を満たしており、ナトリウム（Ｎａ）品位もすべて１０質量ｐｐｍ未満であって、いずれも規定値の１００質量ｐｐｍ以下を満たしていた。また、比表面積は３.２〜３.３ｍ２／ｇの範囲内にあり、いずれも規定値の３ｍ２／ｇ以上であった。更にＤ５０はすべて０.５μｍであり、プレス体の収縮開始温度は６３０〜７８０℃であった。 As can be seen from Table 1 above, the sulfur (S) quality is in the range of 100 ppm to 180 ppm by mass, all satisfying the specified value of 200 ppm by mass or less, and the sodium (Na) quality is all 10 masses. It was less than ppm, and all satisfied the specified value of 100 mass ppm or less. The specific surface area is in the range of 3.2~3.3m 2 / g, was 3m 2 / g or more any specified value. Furthermore, D50 was all 0.5 μm, and the shrinkage start temperature of the pressed body was 630 to 780 ° C.
［実施例２］
洗浄溶液として用いた水酸化ナトリウム水溶液の濃度を０.５質量％に代えて５質量％にした以外は上記実施例１と同様にして、試料９〜１６の酸化ニッケル微粉末を作製し、実施例１と同様に評価した。その結果を下記表２に示す。
[Example 2]
Nickel oxide fine powders of Samples 9 to 16 were prepared and carried out in the same manner as in Example 1 except that the concentration of the sodium hydroxide aqueous solution used as the cleaning solution was changed to 5% by mass instead of 0.5% by mass. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 2 below.
上記表２から分かるように、試料９〜１６の酸化ニッケル微粉末は、硫黄品位が９０〜１９０質量ｐｐｍの範囲内にあり、いずれも規定値の２００質量ｐｐｍ以下を満たしており、ナトリウム品位もすべて１０質量ｐｐｍ未満であって、いずれも規定値の１００質量ｐｐｍ以下を満たしていた。また、比表面積が３.２〜３.３ｍ２／ｇの範囲にあり、いずれも規定値の３ｍ２／ｇ以上であった。更にＤ５０はすべて０.５μｍであり、プレス体の収縮開始温度は５９０〜７９０℃であった。 As can be seen from Table 2 above, the nickel oxide fine powders of Samples 9 to 16 have a sulfur quality in the range of 90 to 190 mass ppm, all satisfying the specified value of 200 mass ppm or less, and the sodium quality is also high. All of them were less than 10 ppm by mass, and all satisfied the specified value of 100 ppm by mass or less. The specific surface area is in the range of 3.2~3.3m 2 / g, was 3m 2 / g or more any specified value. Furthermore, D50 was all 0.5 μm, and the shrinkage start temperature of the press body was 590 to 790 ° C.
［比較例］
洗浄溶液に水酸化ナトリウム水溶液に代えて水を用いた以外は上記実施例１と同様にして試料１７〜２４の酸化ニッケル微粉末を作製し、実施例１と同様に評価した。その結果を下記表３に示す。
[Comparative example]
Nickel oxide fine powders of Samples 17 to 24 were prepared in the same manner as in Example 1 except that water was used in place of the sodium hydroxide aqueous solution for the cleaning solution, and evaluation was performed in the same manner as in Example 1. The results are shown in Table 3 below.
上記表３から分かるように、試料１７〜２４の酸化ニッケル微粉末はナトリウム品位がすべて１０質量ｐｐｍ未満となったものの、硫黄品位が２００〜２６０質量ｐｐｍとなった。また、比表面積は３.２〜３.３ｍ２／ｇ、Ｄ５０はすべて０.５μｍとなったものの、収縮開始温度が８２０〜８７０℃となり、上記した実施例１及び２に比べて顕著に高くなった。 As can be seen from Table 3 above, the nickel oxide fine powders of Samples 17 to 24 all had a sodium grade of less than 10 ppm by mass, but a sulfur grade of 200 to 260 ppm by mass. Moreover, although the specific surface area was 3.2 to 3.3 m 2 / g and D50 was all 0.5 μm, the shrinkage start temperature was 820 to 870 ° C., which was significantly higher than those of Examples 1 and 2 described above. became.
Claims (7)
前記アルカリ洗浄が、アルカリ成分を０.１〜１０質量％含有する水溶液に前記酸化ニッケル微粉末を加えてスラリーとし、該スラリーを撹拌することで洗浄を行うことを特徴とする酸化ニッケル微粉末の製造方法。 A heat treatment step in which a nickel salt is heat-treated in a non-reducing atmosphere at a heat treatment temperature of 800 to 1000 ° C. to form a nickel oxide powder, a crushing step for crushing the nickel oxide powder, and nickel oxide obtained by the crushing A method of producing a nickel oxide fine powder having a washing step of alkaline washing of the fine powder,
In the nickel oxide fine powder, the alkali cleaning is performed by adding the nickel oxide fine powder to an aqueous solution containing 0.1 to 10% by mass of an alkali component to form a slurry, and stirring the slurry. Production method.
The nickel oxide fine powder washed in the washing step has a sulfur quality of 200 mass ppm or less, a sodium quality of 100 mass ppm or less, and a specific surface area of 3 m 2 / g or more. 6. The method for producing a nickel oxide fine powder according to any one of 6 above.
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| JP7559325B2 (en) | 2020-01-14 | 2024-10-02 | 住友金属鉱山株式会社 | Method for calcining nickel hydroxide particles and method for producing nickel oxide fine powder using the same |
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