METHOD FOR PRODUCING NICKEL COMPOSITE HYDROXIDE

• Main Authors: ONO TAMOTSU, OZAWA HIDEZO, RYOSHI KAZUOMI
• Format: Patent
• Language: English; Japanese
• Published: 05.07.2018
• Subjects: BASIC ELECTRIC ELEMENTS; CHEMISTRY; COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSESC01D OR C01F; ELECTRICITY; INORGANIC CHEMISTRY; METALLURGY; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY

PROBLEM TO BE SOLVED: To provide a method for producing a nickel composite hydroxide with an improved process capability index through a continuous crystallization step stabilized for a long term.SOLUTION: A method is provided for producing a nickel composite hydroxide serving as a raw material of a positive electrode active material for a nonaqueous electrolyte secondary battery. With a reaction solution being stirred, a metal salt-containing aqueous solution containing at least nickel, an alkali metal hydroxide, and an ammonium ion supply source are supplied to cause a neutralization reaction to occur to give nickel composite hydroxide particles, which step is referred to as a crystallization step. In the crystallization step, with the concentration of ammonium ions kept at a predetermined control value, the concentration of nickel ions is measured; and on the basis of a deviation of the measured value from a target concentration value of nickel ions, pH is adjusted to allow the concentration of nickel ions to fall at the target value. The adjustment of pH with the use of the nickel ion concentration, which hardly causes measurement errors, as an indirect indicator, enables the particles to be obtained with a desired particle size distribution for a long term.SELECTED DRAWING: Figure 1 【課題】連続晶析工程を長期間安定させ、工程能力指数を向上させニッケル複合水酸化物の製造方法を提供する。【解決手段】非水系電解質二次電池用正極活物質の原材料となるニッケル複合水酸化物の製造方法であって、反応溶液を撹拌しながら、少なくともニッケルを含む金属塩含有水溶液と、アルカリ金属水酸化物、およびアンモニウムイオン供給体を供給して中和反応させ、ニッケル複合水酸化物粒子を得る晶析工程において、アンモニウムイオン濃度を所定の管理値に保ちつつ、ニッケルイオン濃度を測定し、ニッケルイオン濃度の目標値からの偏差に基づいてｐＨを調整して、ニッケルイオン濃度を目標値に収束させる。測定誤差が生じにくいニッケルイオン濃度を間接指標としてｐＨを調整するので、所望の粒度分布の粒子を長期にわたって得ることができる。【選択図】図１