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EP-4736976-A1 - METHOD FOR OBTAINING REPRESENTATIVE PARTICLE SIZE USING TURBIDITY METER IN CRYSTALLIZER AND REPRESENTATIVE PARTICLE SIZE ACQUISITION SYSTEM

EP4736976A1EP 4736976 A1EP4736976 A1EP 4736976A1EP-4736976-A1

Abstract

From basic data of a representative particle size of produced particles acquired by a particle size distribution measuring apparatus, a turbidity of a dispersion of the produced particles, a concentration of the produced particles in the dispersion of the produced particles, and supply amounts of metals derived from metal salts, a correlation equation of these variables is created in advance. In a crystallization step, the representative particle size of the produced particles is acquired using the correlation equation from the turbidity obtained by measuring the dispersion of the produced particles, the concentration of the produced particles, and the supply amount of the metals derived from the metal salts.

Inventors

  • YAIRO, Makoto

Assignees

  • Tsukishima Kikai Co., Ltd.

Dates

Publication Date
20260506
Application Date
20250901

Claims (10)

  1. A method for obtaining a representative particle size of produced particles in a crystallizer (100), characterized in that the representative particle size of the produced particles is obtained in a crystallization step of supplying aqueous solutions each containing each of a plurality of kinds of metal salts to the crystallizer (100) and bringing the metal salts into contact with each other to produce the particles, and the method comprises the steps of: acquiring basic data of the representative particle size of the produced particles acquired by a particle size distribution measuring apparatus, a turbidity of a dispersion of the produced particles, a concentration of the produced particles in the dispersion of the produced particles, and supply amounts of metals derived from the metal salts; creating a correlation equation representing a relationship among the representative particle size of the produced particles, the turbidity of the dispersion of the produced particles, the concentration of the produced particles in the dispersion of the produced particles, and the supply amounts of one or two or more kinds of the metals selected from the metals, obtained in the step of acquiring the basic data; acquiring the turbidity of the dispersion of the produced particles, the concentration of the produced particles, and the supply amounts of the metals derived from the plurality of kinds of metal salts in the crystallization step; and acquiring the representative particle size of the produced particles by the correlation equation based on respective numerical values of the turbidity of the dispersion of the produced particles obtained in the crystallization step, the concentration of the produced particles, and the supply amounts of one or two or more of the metals selected from the metals derived from the metal salts.
  2. The method for obtaining a representative particle size of produced particles in a crystallizer (100) according to claim 1, characterized in that in the step of creating the correlation equation, the plurality of kinds of metal salts are three kinds of metal salts, and when the turbidity of the dispersion of the produced particles is X 1 NTU, the concentration of the produced particles is X 2 % by mass, the supply amounts of the metals are X 3 mol, X 4 mol, and X 5 mol, and the representative particle size of the produced particles is Y µm, the correlation equation is determined by obtaining coefficients a, b, c, d, and e by a least squares method in the following equation representing a relationship between Y and X 1 , X 2 , X 3 , X 4 , and X 5 . Y = aX 1 + bX 2 + cX 3 / X 5 + dX 4 / X 5 + e
  3. The method for obtaining a representative particle size of produced particles in a crystallizer (100) according to claim 2, characterized in that in the step of creating the correlation equation, the plurality of kinds of metal salts are three kinds of metal salts, and the turbidity of the dispersion of the produced particles is X 1 NTU, the concentration of the produced particles is X 2 % by mass, X 3 is the number of moles of cobalt ions, X 4 is the number of moles of manganese ions, and X 5 is the number of moles of nickel ions.
  4. The method for obtaining a representative particle size of produced particles in a crystallizer (100) according to any one of claims 1 to 3, characterized in that the concentration of the produced particles is 1 to 40% by mass.
  5. The method for obtaining a representative particle size of produced particles in a crystallizer (100) according to any one of claims 1 to 3, characterized in that the turbidity is obtained by measurement with a turbidity meter installed in-line in the crystallizer (100).
  6. The method for obtaining a representative particle size of produced particles in a crystallizer (100) according to any one of claims 1 to 3, characterized in that in d10, d50, and d90 of the produced particles acquired by the particle size distribution measuring apparatus based on a volume of the produced particles in the creation of the correlation equation, a value of (d90-d10)/d50 is 1.5 or less.
  7. The method for obtaining a representative particle size of produced particles in a crystallizer (100) according to any one of claims 1 to 3, characterized in that the crystallization step of obtaining the produced particles is a batch type or a continuous type.
  8. A representative particle size acquisition system for produced particles in a crystallizer (100), characterized in that aqueous solutions each containing each of a plurality of kinds of metal salts are supplied to the crystallizer (100) and the metal salts are brought into contact with each other to produce the particles, and the system comprises: a turbidity acquisition unit (110) configured to acquire a turbidity of a dispersion of the produced particles in the crystallizer (100); a produced particle concentration acquisition unit (120) configured to acquire a concentration of the produced particles in the dispersion of the produced particles; a metal supply amount acquisition unit (130) configured to acquire supply amounts of metals derived from the metal salts; a correlation equation creation unit (150) configured to store a correlation equation representing a relationship among the representative particle size of the produced particles acquired by a particle size distribution measuring apparatus, the turbidity of the dispersion of the produced particles, the concentration of the produced particles in the dispersion of the produced particles, and the supply amounts of one or two or more kinds of the metals selected from the metals derived from the metal salts; and a representative particle size calculation unit (140) configured to obtain the representative particle size of the produced particles by the correlation equation based on respective numerical values of the turbidity of the dispersion of the produced particles obtained by the turbidity acquisition unit (110), the concentration of the produced particles obtained by the produced particle concentration acquisition unit (120), and the supply amounts of one or two or more of the metals selected from the metals derived from the metal salts obtained by the metal supply amount acquisition unit (130).
  9. The representative particle size acquisition system for produced particles in a crystallizer (100) according to claim 8, characterized in that the plurality of kinds of metal salts are three kinds of metal salts, and when the turbidity of the dispersion of the produced particles is X 1 NTU, the concentration of the produced particles is X 2 % by mass, the supply amounts of the metals are X 3 mol, X 4 mol, and X 5 mol, and the representative particle size of the produced particles is Y µm, the correlation equation creation unit (150) obtains coefficients a, b, c, d, and e by a least squares method in the following equation representing a relationship between Y and X 1 , X 2 , X 3 , X 4 , and X 5 to create and store the correlation equation. Y = aX 1 + bX 2 + cX 3 / X 5 + dX 4 / X 5 + e
  10. The representative particle size acquisition system for produced particles in a crystallizer (100) according to claim 9, characterized in that X 3 is the number of moles of cobalt ions, X 4 is the number of moles of manganese ions, and X 5 is the number of moles of nickel ions.

Description

Technical Field The present invention relates to a method for acquiring the representative particle size of a crystallization substance produced during crystallization, and a representative particle size acquisition system. Background Art There is a crystallization operation as an operation of precipitating crystals from a liquid phase or the like. Crystallization occurs in a supersaturated state, which can be obtained by cooling, evaporation, reaction, or pressurization. For example, a case where produced particles are produced by the supersaturated state provided by the reaction is called reactive crystallization. In a normal crystallization operation, it is necessary to manufacture crystals having a predetermined representative particle size and particle size distribution. Examples of the applications of crystallization include the manufactures of a precursor of a positive electrode material for a lithium ion battery, various inorganic materials, a cosmetic material, and the like, and in these applications, the representative particle size and the particle size distribution are important physical property values in order for a material obtained by the crystallization to exhibit performance. Therefore, it is important to acquire information on the particle sizes of the produced particles in order to secure the performance thereof. Examples of a method for measuring the particle sizes of particles in the order of microns and submicrons include a dynamic light scattering method, a laser diffraction method/scattering method, a centrifugal sedimentation method, and an image analysis method, but all measuring instruments for the methods are expensive or require time for measurement. Meanwhile, a method that enables efficient particle size measurement at low cost has been proposed (Patent Literature 1). The disclosed method includes the steps of: mixing a predetermined amount of a suspended substance having a known average particle size with water for each average particle size to create a suspension for each average particle size; measuring the turbidity of the suspension for each average particle size to specify a correspondence relationship between the average particle size and the turbidity; and measuring the turbidity of a target suspension containing the suspended substance to be measured for particle size, and collating the measured turbidity with the correspondence relationship to specify the average particle size of the suspended substance contained in the target suspension. Specifically, a graph of the turbidity and the particle size is created for each amount (concentration) of the suspended substance, and the turbidity of the target suspension is collated with the turbidity-average particle size relationship graph. Here, the graph is created for each concentration of the suspension, and it is necessary to adjust the concentration of the target suspension to the concentration of the suspended substance in the graph created above. Patent Literature 1 discloses that a graph is created for each color and concentration of suspended substances that are kaolin (white), slate (gray), and basic volcanic rocks (brown), and the turbidity of the target suspension is collated with a graph of a corresponding color in the turbidity-average particle size relationship graph to specify the average particle size of the suspended substance contained in the target suspension having a color tone of any of white, gray, and brown. Also in this case, it is necessary to adjust the concentration of the target suspension to the concentration of the suspended substance in the graph created above. Furthermore, it is necessary to select the turbidity-average particle size relationship graph for each color of the suspended substance. Citation List Patent Literature Patent Literature 1: JP 2008-191057 A Summary of Invention Technical Problem The prior art utilizes the turbidity-average particle size relationship graph created for each concentration of the suspended substance or the turbidity-average particle size relationship graph created for each concentration of the suspended substance and for each of three colors. Therefore, it is necessary to adjust the concentration of the target suspension to the concentration of the suspended substance in the created graph, and when the suspended substance is colored, it is necessary to use the turbidity-average particle size relationship graph of the color, and it is difficult to apply the same method in a concentration crystallization process in which the average particle size varies depending on the turbidity of the suspension, the concentration of a slurry, and the supply amount of a raw material substance. An object of the present invention is to provide a method for acquiring the particle sizes of produced particles in a crystallizer using one correlation equation from the turbidity, the concentration of the produced particles, the supply amount of the raw material substance, and the