JP2018053282A - Method for producing nickel oxide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing nickel oxide, in a process where nickel hydroxide is roasted using a fluid roasting furnace to produce nickel oxide, characterized in that inexpensive white molten alumina and brown molten alumina are used as fluid media.SOLUTION: In the process where nickel hydroxide is roasted using a fluid roasting furnace to produce nickel oxide, by using white molten alumina and brown molten alumina as fluid media, nickel oxide in which the grade of Si in the roasted matter is low is inexpensively produced. More concretely, the average particle size of the fluid media and the treated product lies in the range of 0.1 to 10 by the ratio of the fluid media/the nickel hydroxide. Further, the roasting temperature is 800 to 1,200°C.SELECTED DRAWING: None

Description

The present invention relates to a method for producing nickel oxide by roasting nickel hydroxide using a fluid roasting furnace.

A general fluid roasting furnace is a furnace in which granular raw materials to be roasted while supplying gas can be efficiently roasted by floating, that is, fluidizing, like a fluid. On the other hand, in the case of fine powder such that the particle size of the raw material is less than 50 μm, it is often difficult to fluidize the raw material alone, and thus a material that is easy to fluidize is used as the fluidizing medium. The raw material and the fluid medium are mixed to facilitate fluidization.

Further, in order to reliably roast the supplied raw material, it is necessary to make the gas flow rate charged in the fluid roasting furnace equal to or higher than the minimum fluidization speed and at the same time stably maintain the terminal speed or lower. When the gas flow rate is reduced to less than the minimum fluidization speed, the raw material does not fluidize, and as a result, problems such as occurrence of aggregation of the raw material without roasting proceeding uniformly occur. On the other hand, if the gas flow rate becomes larger than the terminal velocity, the flow rate is too high and the raw material is flowed out of the furnace together with the gas, so that it cannot be sufficiently roasted and sufficient quality cannot be obtained, or the yield There is a problem that the value of the value drops significantly. That is, in fluid roasting using fine powder as a raw material, it is necessary to select an appropriate fluid medium as well as stabilizing the gas flow rate.
The characteristics required of a fluid medium used in a fluid roasting furnace as an industrial process are required not to react with the raw material at the reaction temperature, and to be inexpensive and generally available.

Patent Document 1 relates to a technique for preventing a fluid medium from solidifying in a supply pipe in a fluidized bed boiler, and describes that the material of the fluid medium is coal ash and calcium of limestone.
However, in this example, what is used as a functional material that requires high purity after roasting, such as nickel oxide, is not manufactured, and the reaction between the fluidized medium and the processed material is not well understood.
Thus, in order to obtain a fine material such as nickel oxide that can be used for various functional materials, electronic materials, and energy materials, a necessary fluid medium and its specific method of use have not been known.

Japanese Patent Laid-Open No. 06-249407

  The present invention stably maintains a fluid state without affecting the quality of the material to be baked in the step of producing fine nickel oxide by roasting nickel hydroxide using a fluid roasting furnace. It is intended to provide a fluid medium that can be used and its method of use.

  This inventor repeated earnest examination in order to solve the subject mentioned above. As a result, in the step of producing nickel oxide by roasting nickel hydroxide, it is roasted using a fluid roasting furnace, and white molten alumina or The inventors have found that by using brown molten alumina as a fluid medium, it is possible to produce a high-quality nickel oxide that maintains a stable fluid state and does not contain impurities from the fluid medium. That is, the present invention provides the following.

  In the first aspect of the present invention, nickel hydroxide is charged into a fluid roasting furnace and roasted, and in the step of producing nickel oxide, as a fluid medium charged into the fluid roasting furnace together with nickel hydroxide, A method for producing nickel oxide, characterized by using white fused alumina and / or brown fused alumina.

  In the second aspect of the present invention, in the roasting of the first aspect, the average particle size of the fluid medium to be charged and the average particle size of the nickel hydroxide to be charged are 0 in the ratio of fluid medium / nickel hydroxide. The method for producing nickel oxide is characterized in that the size of the fluidized medium and / or the size of nickel hydroxide is adjusted to a value in the range of 1 to 10.

  The third invention of the present invention is the method for producing nickel oxide according to the first and second inventions, wherein the furnace temperature during roasting is in the range of 800 ° C to 1200 ° C. .

  According to the present invention, in the step of roasting nickel hydroxide to produce nickel oxide, when roasting using a fluid roasting furnace, and roasting nickel hydroxide to produce nickel oxide, By using white molten alumina or brown molten alumina as a fluid medium, it is possible to produce a high-quality nickel oxide that maintains a stable fluid state and does not contain impurities from the fluid medium.

In the present invention, in the step of obtaining nickel oxide by roasting powdered nickel hydroxide using a fluid roasting furnace, white molten alumina or brown molten alumina that is also used as an abrasive is used for the fluid medium. It is characterized by.
Further, by using the above-mentioned fluid medium and the atmosphere as the gas, it is possible to produce a high-quality nickel oxide that maintains a stable fluid state and does not contain impurities from the fluid medium.

  Hereinafter, a specific embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. In addition, this invention is not limited to the following embodiment, A various change is possible in the range which does not change the summary of this invention.

[1. material]
The raw material used for fluid roasting in the present invention is nickel hydroxide (Ni (OH) ₂ )).
When this nickel hydroxide is roasted to obtain, for example, high-purity nickel oxide (NiO) used as a raw material for battery materials, if Si is contained, battery characteristics may be deteriorated. Therefore, for such applications, it is desirable that the fluid medium does not contain silicon dioxide (SiO ₂ ).
In the present invention, alumina is used as the fluid medium. For this reason, it is possible to manufacture high purity nickel oxide with low Si quality.
The particle size of nickel hydroxide used for fluid roasting in the present invention can be uniformly roasted in a relatively short time to the inside of the particles when the average particle size is several μm to several 100 μm. preferable.
On the other hand, if coarse particles with an average particle size exceeding 1 mm are used, it takes time to uniformly roast the inside of the particles, and the method of partial roasting is partially biased, resulting in non-uniform quality. Since it becomes easy to become, it is not preferable.

[2. Fluid roasting process]
The fluidized roasting furnace in the present invention is fired in a state where gas is flowed from the lower side of the furnace and the raw material and the fluidized medium are fluidized.
The outline of the fluid roasting furnace that can be used in the present invention will be described. A fluid roasting furnace having a normal vertical structure can be used. At the bottom of the furnace, there is a fixed layer on the gas inlet tube, on which a fluid medium is placed. A heater is provided in the periphery of the core tube over and above the portion where the fixed bed and the fluid medium are placed to maintain the necessary roasting temperature. Moreover, it has the raw material injection | throwing-in pipe | tube which introduce | transduces nickel hydroxide in the position of the core tube which is above the level of a fluid medium in a stationary state. The upper part of the core tube is connected to a recovery cyclone, where the gas and the nickel oxide produced by roasting are separated, the gas is exhausted, and the nickel oxide is recovered.
More specifically, a fixed layer is made of bead-shaped alumina at the bottom of the furnace to rectify the gas. Since the fixed layer is not in direct contact with the processed material, it is not necessarily required to be alumina. A fluid medium is placed on the fixed bed. The particle size of the fluid medium is selected such that the average particle size of the fluid medium charged and the average particle size of the nickel hydroxide charged are in the range of the fluid medium / nickel hydroxide ratio of 0.1 to 10. That's fine.
The temperature during roasting is preferably 800 ° C. or higher and 1200 ° C. or lower. If it is less than 800 ° C., it may take a long time to roast, or it may be impossible to perform uniform roasting because the temperature is low. On the other hand, even if it exceeds 1200 ° C., the conveyance is hardly promoted, which is not preferable because the energy cost is increased and the life of the heater and the furnace body is shortened.
A roasting temperature of 850 ° C. or higher and 1000 ° C. or lower is preferable because it can be efficiently and uniformly roasted and the running cost can be suppressed.
The roasting time of the to-be-roasted object is not particularly limited, but if it is too short, roasting becomes insufficient and the quality and purity are lowered. On the other hand, if the roasting time is longer than necessary, the electric cost and the fuel cost become high and the processing time becomes long. The treatment time of the to-be-roasted object is preferably about 3 minutes or more and 50 minutes or less, although there is an influence of the size and structure of the apparatus. Within this range, efficient and uniform roasting can be performed.

  As described above, according to the present invention, the intended to-be-baked product is industrialized by using a fluid medium that is fluidized in a mixed state with the raw material, does not react with the raw material at the reaction temperature, and is inexpensive and generally available. Can be manufactured.

EXAMPLES Hereinafter, although an Example, a comparative example, and a reference example are shown and this invention is demonstrated more concretely, this invention is not limited to a following example at all.

[Examples 1 to 3]
[material]
First, nickel hydroxide prepared by a known method was prepared as a raw material to be roasted. The average particle size is in the range of 22.5 to 24.5 μm. First, in order to remove moisture adhering to the nickel hydroxide crystals, vacuum heat treatment was performed in vacuum at 180 ° C. for 2 hours. The water adhering to the nickel hydroxide was substantially removed by this vacuum heat treatment.
In addition, although the prepared nickel hydroxide used the thing which is actually used for an operation, the same thing was used, but about 1.7 to 2.3 weight% of sulfur content is contained. In addition, components inevitably included are small in content and can be substantially ignored.

[Flow roasting]
For fluid roasting, a fluid roasting furnace manufactured by Niijima Neolite Industry Co., Ltd. was used. The inner diameter of the core is 100 mm in diameter, and the effective soaking zone is about 500 mm in height.
First, alumina as a fixed layer is added, and then the molten medium is brown molten alumina having an average particle size of 100 μm (Example 1), white molten alumina having an average particle size of 100 μm (Example 2), and white molten alumina having an average particle size of 150 μm (Example). 3) was introduced.
The above-mentioned various molten aluminas that are fluid media are generally used as abrasives, are industrially mass-produced, are stably supplied and are available at low cost, and are suitable for the practice of the present invention.
Next, the temperature is raised to a predetermined roasting temperature while flowing air. The air flow rate was the same for all samples during roasting, and this value was set to 1 to relatively represent the flow rate during roasting. In all samples, the roasting temperature was 900 ° C. and the roasting time was 30 minutes.
Each sample was evaluated based on the nickel oxide content and aluminum content of the sample after roasting. Specifically, the evaluation was as follows.

[Content of nickel oxide in roasted sample]
The contents of nickel oxide and nickel hydroxide in the sample recovered after roasting were calculated, and the ratio of nickel oxide was determined from these two values.
In Examples 1 to 3 according to the present invention, the quality of nickel oxide of the obtained roasted product is 99.9%, 99.7%, 99.8%, and the aluminum quality is less than 0.01%. It was good and almost all of the supplied nickel hydroxide could be roasted into nickel oxide. Moreover, both the brown fused alumina and the white fused alumina of the fluid media used in Examples 1 to 3 can be obtained at a low price of about 300 to 400 yen per kg, and the influence on industrial costs is slight. is there.
On the other hand, the fluid medium used in Examples 1 to 3 according to the present invention has a commercial price of about 350 yen per kg and is relatively inexpensive.

[Comparative Example 1]
Nickel hydroxide was fluidly roasted using the same method as in Examples 1 to 3 above, except that high-purity alumina beads having a diameter of 100 μm were used as the fluid medium, thereby obtaining nickel oxide.
Although the quality of nickel oxide in the roasted product is 99.7% and the aluminum content is less than 0.01%, the quality is equivalent to that of Examples 1 to 3, but the high purity of the fluidized medium used. Alumina beads are expensive at a commercial price of about 80,000 yen per kg, and when used industrially, the impact on the cost becomes large.

  Thus, it was confirmed that high-quality nickel oxide can be produced with high productivity by roasting nickel hydroxide using the fluid medium and the fluid roasting furnace of the present invention.

Claims (3)

  In the process of charging nickel hydroxide into a fluid roasting furnace and baking it to produce nickel oxide, white molten alumina and / or brown molten alumina is used as a fluid medium charged into the fluid roasting furnace together with nickel hydroxide. The manufacturing method of the nickel oxide characterized by using.   In the roasting according to claim 1, the average particle size of the fluid medium to be charged and the average particle size of the nickel hydroxide to be charged are in the range of 0.1 to 10 in terms of the fluid medium / nickel hydroxide ratio. And adjusting the size of the fluid medium and / or the size of nickel hydroxide.   3. The method for producing nickel oxide according to claim 1 or 2, wherein the temperature in the furnace during roasting is in the range of 800C to 1200C.