CN116768279A - Iron oxide red powder and preparation method thereof - Google Patents

Abstract

The invention relates to an iron oxide red powder and a preparation method thereof. Compared with the iron oxide red powder produced by existing steel plants or pigment factories, the iron oxide red powder of the present invention has higher purity, lower impurity content, smaller particle size, high sphericity, and large specific surface area, and the preparation method of the present invention The process is simple, the cost is low, the energy consumption is low, the output is large, and it is suitable for industrial large-scale production.

Description

Iron oxide red powder and preparation method thereof

Technical field

The invention relates to an iron oxide red powder and a preparation method thereof. Specifically, the present invention relates to a production process for increasing the iron oxide content and particle spheroidization in iron oxide red, and belongs to the field of battery new energy materials.

Background technique

There are many methods for preparing iron oxide red. There are two main process routes for large-scale production of iron oxide red. One is that the pigment factory reacts waste iron sheets with acid to prepare a ferrous solution, which is alkalized to generate ferrous hydroxide, and then It is formed by continuous oxidation and precipitation in the reaction barrel, commonly known as the precipitation method; one is formed by spraying and calcining the ferrous solution after pickling the steel plate in the steel plant under high temperature conditions, commonly known as the roasting method or the Lu type method. The iron oxide red produced by the precipitation method has the advantages of small particle size, high specific surface area and high hiding power, but the production process is long, the impurity content is high, the iron oxide content in the product is less than 97%, and the particle shape is difficult to control; roasting The iron oxide red produced by this method has the advantages of iron oxide content greater than 97%, simple process, large output, and short production cycle. However, the resulting product has the disadvantages of large particle size, small specific surface area, high chlorine content, and large fluctuations in metal impurity content.

Patent Document 1, Patent Document 2 and Patent Document 3 all use water to wash iron oxide powder. The ability to remove metal impurities in iron oxide powder is limited and cannot remove most metal impurities below 100 ppm; and it is not used during processing. Grinding aids require longer grinding times and higher energy consumption; their improvement in iron oxide content is limited.

The overall performance of the above-mentioned products cannot meet the requirements of new battery energy materials for iron oxide red with high purity, low impurities, spherical, uniform and miniaturized grain morphology, and cannot be used in this field on a large scale.

Citation

Patent document 1: CN107601575A

Patent document 2: CN100366544A

Patent document 3: CN105399143A

Contents of the invention

Invent the problem to be solved

In view of the above reasons, the present invention provides a production process for increasing the iron oxide content and spheroidizing the particles, which can effectively reduce various impurities in the iron oxide red in the above two processes, increase the iron oxide content, and spherical the grain morphology. , homogenization, miniaturization. The invention has simple process, low cost, low energy consumption and large output, and is suitable for industrial large-scale production.

solutions to problems

The object of the present invention can be achieved through the following technical solutions:

[1] An iron oxide red powder containing 98.0% by mass or more of Fe ₂ O ₃ and containing K, Na, Ca, Mg, Zn, Cu, and Ti each in an amount of 0.01% by mass or less,

The iron oxide red has a substantially spherical shape and a median particle diameter D50 of 0.2 μm to 1.0 μm.

[2] The iron oxide red powder according to the above [1], wherein the K content is 15 ppm or less, preferably 10 ppm or less; and/or the Na content is 95 ppm or less, preferably 85 ppm or less; and/or the Ca content 80 ppm or less, preferably 50 ppm or less; and/or the Mg content is 60 ppm or less, preferably 40 ppm or less; and/or the Zn content is 65 ppm or less, preferably 45 ppm or less; and/or the Cu content is 60 ppm or less, preferably 40 ppm or less. 40 ppm or less; and/or the Ti content is 90 ppm or less, preferably 86 ppm or less.

[3] The iron oxide red powder according to the above [1] or [2], which further contains Mn in a content of 0.18% by mass or less, preferably 0.15% by mass or less; and/or further contains Mn in a content of 0.1% by mass or less , preferably 0.08% by mass or less of Al; and/or also contain Cl in a content of 0.1% by mass or less.

[4] The iron oxide red powder according to any one of the above [1] to [3], wherein the median particle diameter D50 of the iron oxide red powder is 0.3 μm to 0.8 μm; and/or the oxidation The D10 of the iron red powder is 0.1 μm to 0.5 μm, and the D97 is 0.8 μm to 1.5 μm; and/or the volume average particle size of the iron oxide red powder is 0.3 to 0.9 μm; and/or the iron oxide red powder The specific surface area of the powder is more than 2000m ² /kg.

[5] A method for preparing iron oxide red powder according to any one of the above [1] to [4], which includes the following steps:

A suspension preparation step of mixing a dilute acid solution, a dispersant and iron oxide red powder to obtain an iron oxide red suspension;

The obtained suspension is ground to obtain a grinding slurry, and then the grinding and demagnetization step is performed to obtain a demagnetized grinding slurry;

The preparation steps of filtering, cleaning and drying the demagnetized grinding slurry to obtain crude iron oxide red crude product; and

A spheroidizing step of pulverizing the crude iron oxide red product to obtain spherical iron oxide red powder as the product.

[6] The preparation method according to the above [5], wherein the dilute acid is sulfuric acid, nitric acid, formic acid, acetic acid, carbonic acid, oxalic acid, citric acid, malic acid, tartaric acid, succinic acid, benzoic acid, salicylic acid One or more of; and/or, the concentration of the dilute acid solution is 0.2 to 2.0 mass%.

[7] The preparation method according to the above [5] or [6], wherein the dispersant is a nonionic surfactant, and the nonionic surfactant includes polyoxyethylene ethers, polyols, polyvalent alcohols, One or more of alcohol esters and amide types; and/or the polyoxyethylene ethers include one of alkylphenol polyoxyethylene ethers, fatty alcohol polyoxyethylene ethers, and fatty acid polyoxyethylene ethers. or more; and/or, the polyols include one or more of polyethylene glycol 200, polyethylene glycol 400, polyethylene glycol 600, polypropylene glycol, and polybutylene glycol; and/or , the polyol esters include one or more of Tween 20, Tween 40, Tween 60, and Tween 80; and/or the amide type includes stearic acid diethanolamide, coconut oil One or more of diethanolamide and coco acid monoethanolamide.

[8] The preparation method according to any one of the above [5] to [7], wherein the proportion of the dispersant in the iron oxide red suspension is 0.2 to 2.0 mass%; and/or, the The proportion of iron oxide red powder in the iron oxide red suspension is 40 to 80 mass%.

[9] The preparation method according to any one of the above [5] to [8], wherein the demagnetization is performed by passing the pipe demagnetizer in the process of sending the grinding slurry to the filtration device; and/or, the The above-mentioned cleaning is performed by using pure water with a conductivity of 10 megaohms.

[10] The preparation method according to any one of the above [5] to [9], wherein the spheroidization step includes coarsely crushing the crude iron oxide red product, and then finely crushing and sphericalizing the crude iron oxide red product by using a jet mill. to obtain spherical iron oxide red powder as the product.

Effect of the invention

Compared with the prior art, the present invention has the following beneficial effects:

1) The iron oxide red powder of the present invention has a substantially spherical shape, a narrow particle size distribution, a significant reduction in metal impurity content, and an increased iron oxide red content.

2) In the preparation method of the present invention, various impurities and magnetic impurities wrapped inside the iron oxide powder are removed through acid leaching, grinding and refinement, and magnetic separation, and then are washed with pure water to increase the iron oxide in the iron oxide red powder. content, and the particles are spheroidized through a jet mill, so that the produced iron oxide red powder can meet the raw material requirements for battery new energy materials.

3) The present invention has simple process, normal temperature operation, low cost, low energy consumption and large output, and is suitable for industrial large-scale production.

Description of drawings

Figure 1A is a particle size distribution diagram of the untreated iron oxide red powder in Example 1.

Figure 1B is a particle size distribution diagram of the iron oxide red product after treatment in Example 1.

Figure 2A shows the particle size distribution diagram of the untreated iron oxide red powder in Example 2.

Figure 2B is a particle size distribution diagram of the iron oxide red product after treatment in Example 2.

Figure 3A is a particle size distribution diagram of the untreated iron oxide red powder in Example 3.

Figure 3B is a particle size distribution diagram of the iron oxide red product after treatment in Example 3.

Figure 4A is a scanning electron microscope photograph of the untreated iron oxide red powder in Example 1.

Figure 4B is a scanning electron microscope photograph of the iron oxide red product after treatment in Example 1.

Detailed ways

Embodiments of the present invention will be described below, but the present invention is not limited thereto. The present invention is not limited to each configuration described below, and various changes can be made within the scope of the claimed invention. Embodiments and examples obtained by appropriately combining the technical means disclosed in different embodiments and examples are also included in the present invention. within the technical scope of the invention. In addition, all documents described in this specification are cited in this specification as references.

Unless otherwise defined, technical and scientific terms used herein have the same meanings commonly understood by one of ordinary skill in the art to which this invention belongs.

In this specification, the numerical range represented by "numeric value A to numerical value B" refers to the range including the endpoint values A and B.

In this specification, unless otherwise stated, "many" in "many", "many", "plurality", etc. means a numerical value of 2 or more.

In this specification, "substantially" means that the difference is less than 5%, or less than 3%, or less than 1% compared with the relevant perfect standard or theoretical standard.

In this specification, unless otherwise specified, "%" means mass percentage.

In this manual, unless otherwise specified, "ppm" means mass ppm.

In this specification, "D10", "D50" and "D97" have common meanings in this field. For example, D10 is the particle size corresponding to when the cumulative particle size distribution number of a sample reaches 10%. Its physical meaning is that 10% of the particles have a particle size smaller than it. Similarly, D50 is the particle size corresponding to when the cumulative particle size distribution percentage of a sample reaches 50%. Its physical meaning is that particles larger than it account for 50%, and particles smaller than it also account for 50%, so D50 is also called Median diameter or median particle size. Similarly, D97 is the particle size corresponding to when the cumulative particle size distribution number of a sample reaches 97%. Its physical meaning is that 97% of the particles have a particle size smaller than it.

In this specification, "span" is a value calculated using the formula (D90-D10)/D50.

In this specification, the meaning of "can" includes both the meaning of performing certain processing and the meaning of not performing certain processing.

In this specification, "optional" or "optionally" means that the next described event or situation may or may not occur, and the description includes situations where the event occurs and situations where the event does not occur.

In this specification, "include" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method or system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes Other steps or units inherent in such processes, methods, products or devices.

In this specification, references to "some specific/preferred embodiments", "other specific/preferred embodiments", "implementations", etc. refer to the specific elements described related to the embodiment (for example, Features, structures, properties and/or characteristics) are included in at least one embodiment described herein and may or may not be present in other embodiments. Additionally, it is to be understood that the described elements may be combined in various embodiments in any suitable manner.

[first]

A first aspect of the invention relates to an iron oxide red powder having a spherical shape or a substantially spherical shape and a narrow particle size distribution.

In a specific embodiment of the present invention, the median particle size D50 of the iron oxide red powder is 0.2 μm to 1.0 μm, preferably 0.3 μm to 0.8 μm, D10 is 0.1 μm to 0.5 μm, and D97 is 0.8 μm to 1.5 μm. The volume average particle diameter of the iron oxide red powder is 0.3 μm to 0.9 μm, preferably 0.4 μm to 0.8 μm. The particle size distribution of the iron oxide red powder has a span of 1.0 to 1.8, preferably 1.0 to 1.6.

In some specific embodiments of the present invention, the specific surface area of the iron oxide red powder may be more than 2000 m ² /kg, preferably more than 2500 m ² /kg. Although the upper limit of the specific surface area is not particularly limited, generally the specific surface area of the iron oxide red powder may be 8000 m ² /kg or less, preferably 7000 m ² /kg or less. For example, the specific surface area of the iron oxide red powder may be 2000 m ² /kg or more and 8000 m ² /kg or less.

The iron oxide red powder of the present invention also has the characteristics of high Fe ₂ O ₃ content and greatly reduced impurity content. Specifically, the iron oxide red powder of the present invention contains 98.0% by mass or more of Fe ₂ O ₃ and contains K, Na, Ca, Mg, Zn, Cu, and Ti each in an amount of 0.01% by mass or less (that is, 100 ppm or less). .

In the present invention, the iron oxide red powder contains 98.0% by mass or more of Fe ₂ O ₃ . For example, the Fe ₂ O ₃ content may be 98.0 mass%, 98.2 mass%, 98.4 mass%, 98.6 mass%, 98.8 mass%, 99.0 mass%, 99.2 mass%, 99.5 mass%, etc. These values may be combined in any manner to form a range of values. For example, the Fe ₂ O ₃ content may be 98.0 mass% to 99.5 mass%, or 98.4 mass% to 99.5 mass%, or the like.

In some embodiments of the invention, the content of K is 15 ppm or less, preferably 10 ppm or less, more preferably 5 ppm or less, or even less than 1 ppm. On the other hand, the K content may be 0.5 ppm or more. For example, the content of K can be 0.5ppm, 1ppm, 2ppm, 3ppm, 4ppm, 5ppm, 6ppm, 7ppm, 8ppm, 9ppm, 10ppm, 12ppm, 15ppm, etc. These values may be combined in any manner to form a range of values. For example, the K content may be 0.5 ppm to 15 ppm, 0.5 ppm to 5 ppm, etc.

In some embodiments of the invention, the content of Na is 95 ppm or less, preferably 85 ppm or less, more preferably 50 ppm or less. On the other hand, the content of Na may be 20 ppm or more. For example, the content of Na may be 20 ppm, 30 ppm, 40 ppm, 50 ppm, 60 ppm, 70 ppm, 80 ppm, 85 ppm, 90 ppm, 95 ppm. These values may be combined in any manner to form a range of values. For example, the Na content may be 20 ppm to 95 ppm, 20 ppm to 85 ppm, etc.

In some embodiments of the invention, the content of Ca is 80 ppm or less, preferably 50 ppm or less. On the other hand, the content of Ca may be 10 ppm or more. For example, the content of Ca can be 10 ppm, 20 ppm, 30 ppm, 40 ppm, 50 ppm, 60 ppm, 70 ppm, or 80 ppm. These values may be combined in any manner to form a range of values. For example, the content of Ca may be 10 ppm to 80 ppm, 10 ppm to 50 ppm, etc.

In some embodiments of the invention, the content of Mg is 60 ppm or less, preferably 40 ppm or less, more preferably 30 ppm or less. On the other hand, the Mg content may be 5 ppm or more. For example, the content of Mg may be 5 ppm, 10 ppm, 20 ppm, 30 ppm, 40 ppm, 50 ppm, or 60 ppm. These values may be combined in any manner to form a range of values. For example, the Mg content may be 5 ppm to 60 ppm, 5 ppm to 40 ppm, etc.

In some embodiments of the invention, the content of Zn is 65 ppm or less, preferably 45 ppm or less, more preferably 40 ppm or less. On the other hand, the Zn content may be 10 ppm or more. For example, the Zn content may be 10 ppm, 15 ppm, 20 ppm, 25 ppm, 30 ppm, 35 ppm, 40 ppm, 45 ppm, 50 ppm, 55 ppm, 60 ppm, 65 ppm. These values may be combined in any manner to form a range of values. For example, the Zn content may be 10 ppm to 65 ppm, 10 ppm to 40 ppm, etc.

In some embodiments of the invention, the Cu content is 60 ppm or less, preferably 40 ppm or less. On the other hand, the Cu content may be 15 ppm or more. For example, the Cu content may be 15 ppm, 20 ppm, 25 ppm, 30 ppm, 35 ppm, 40 ppm, 45 ppm, 50 ppm, 55 ppm, or 60 ppm. These values may be combined in any manner to form a range of values. For example, the Cu content may be 15 ppm to 60 ppm, 15 ppm to 50 ppm, etc.

In some embodiments of the invention, the Ti content is 90 ppm or less, preferably 86 ppm or less. On the other hand, the Ti content may be 30 ppm or more. For example, the content of Ti can be 30ppm, 40ppm, 45ppm, 50ppm, 55ppm, 60ppm, 65ppm, 70ppm, 75ppm, 80ppm, 86ppm, 90ppm. These values may be combined in any manner to form a range of values. For example, the Ti content may be 30 ppm to 90 ppm, etc.

In other embodiments of the present invention, the iron oxide red powder also contains Mn in a content of 0.18 mass% or less, preferably 0.15 mass% or less. On the other hand, the Mn content may be 10 ppm or more. Specifically, the content of Mn can be 10ppm, 20ppm, 30ppm, 40ppm, 50ppm, 60ppm, 70ppm, 80ppm, 90ppm, 100ppm (i.e. 0.01 mass%), 0.05 mass%, 0.08 mass%, 0.1 mass%, 0.12 mass%, 0.15% by mass, 0.18% by mass. These values may be combined in any manner to form a range of values. For example, the Mn content may be 10 ppm to 0.18 mass%, 20 ppm to 0.15 mass%, or the like.

In other embodiments of the present invention, the iron oxide red powder also contains Al in a content of 0.1 mass% or less, preferably 0.08 mass% or less. On the other hand, the Al content may be 30 ppm or more. Specifically, the content of Al can be 30 ppm, 40 ppm, 50 ppm, 60 ppm, 70 ppm, 80 ppm, 90 ppm, 100 ppm (ie 0.01 mass %), 0.03 mass %, 0.05 mass %, 0.07 mass %, 0.09 mass %, 0.1 mass %. These values may be combined in any manner to form a range of values. For example, the Al content may be 30 ppm to 0.1 mass%, 30 ppm to 0.07 mass%, or the like.

In other embodiments of the present invention, the iron oxide red powder further contains Cl in a content of 0.1 mass% or less. On the other hand, the Cl content may be 1 ppm or more. Specifically, the content of Cl can be 1 ppm, 5 ppm, 10 ppm, 30 ppm, 50 ppm, 80 ppm, 100 ppm (ie 0.01 mass %), 0.03 mass %, 0.05 mass %, 0.07 mass %, 0.09 mass %, 0.1 mass %. These values may be combined in any manner to form a range of values. For example, the Cl content may be 1 ppm to 0.1 mass %, 1 ppm to 0.09 mass %, etc.

[Second aspect]

The second aspect of the present invention relates to a method for preparing iron oxide red powder (or a method for purifying and spheroidizing iron oxide red powder).

The preparation method of iron oxide red powder of the present invention includes the following steps:

A suspension preparation step of mixing a dilute acid solution, a dispersant and iron oxide red powder to obtain an iron oxide red suspension;

The obtained suspension is ground to obtain a grinding slurry, and then the grinding and demagnetization step is performed to obtain a demagnetized grinding slurry;

The preparation steps of filtering, cleaning and drying the demagnetized grinding slurry to obtain crude iron oxide red crude product; and

A spheroidizing step of pulverizing the crude iron oxide red product to obtain spherical iron oxide red powder as the product.

These steps are explained in detail below.

Suspension preparation steps

In an embodiment of the present invention, an iron oxide red suspension is prepared by mixing a dilute acid solution, a dispersant and iron oxide red powder.

The dilute acid used to prepare the suspension may be one or more of sulfuric acid, nitric acid, formic acid, acetic acid, carbonic acid, oxalic acid, citric acid, malic acid, tartaric acid, succinic acid, benzoic acid, and salicylic acid. When multiple types of them are used, the ratio between them is not particularly limited and may be any ratio.

In some specific embodiments of the present invention, the concentration of the dilute acid solution used is 0.2 to 2.0 mass%, preferably 0.5 to 1.5 mass%. In the present invention, the dilute acid solution can be used directly or can be obtained by diluting concentrated acid with water. In addition, it should be noted that the acid used in the present invention may be an industrial acid.

In the present invention, the dispersant may be a nonionic surfactant. The nonionic surfactant includes one or more of polyoxyethylene ethers, polyols, polyol esters, and amide types. When multiple types of them are used, the ratio between them is not particularly limited and may be any ratio.

Examples of the polyoxyethylene ethers include alkylphenol polyoxyethylene ethers, fatty alcohol polyoxyethylene ethers, fatty acid polyoxyethylene ethers, and the like.

Among them, examples of alkylphenol polyoxyethylene ether may include octylphenol polyoxyethylene ether and nonylphenol polyoxyethylene ether. Examples of octylphenol oxyethylene ethers may include OP-10. Examples of nonylphenol polyoxyethylene ethers may include NP-10, NP-30, NP-40, etc. Examples of fatty alcohol polyoxyethylene ethers may include AEO-9, AEO-15, AEO-30, etc. Examples of fatty acid polyoxyethylene ethers may include SG-40, SG-100, etc.

Examples of the polyols may include polyethylene glycol 200, polyethylene glycol 400, polyethylene glycol 600, polypropylene glycol, polybutylene glycol, and the like.

Examples of the polyol esters may include Tween 20, Tween 40, Tween 60, Tween 80, and the like.

Examples of the amide type may include stearic acid diethanolamide, coco acid diethanolamide, coco acid monoethanolamide, and the like.

In the present invention, the iron oxide red powder is not particularly limited, and the iron oxide red powder produced by steel plants or pigment factories can be directly used.

In some specific embodiments of the present invention, the proportion of the dispersant in the iron oxide red suspension is 0.2 to 2.0 mass%, preferably 0.5 to 1.5 mass%. The proportion of iron oxide red powder in the iron oxide red suspension is 40 to 80 mass%, preferably 50 to 70 mass%.

In addition, since the iron oxide suspension of the present invention is acidic, the mixing and dispersing container needs to be acid-resistant.

Grinding and Demagnetization Steps

After preparing the iron oxide red suspension, the obtained suspension is ground to obtain a polishing slurry, and then the polishing slurry is demagnetized to prepare a demagnetizing polishing slurry. Through grinding, refinement and demagnetization (or magnetic separation), various impurities and magnetic impurities wrapped inside the iron oxide powder can be removed.

In the specific embodiment of the present invention, the grinder used for grinding the suspension is not particularly limited, and commonly used grinders can be used, examples of which may include sand mills, ball mills, and the like. For example, a vertical sand mill using zirconia with a diameter of 0.5 to 2.5 mm can be used. Since the iron oxide red suspension of the present invention is acidic, the grinder needs to be acid-resistant.

There are no particular restrictions on the grinding machine rotation speed and grinding time. For example, the rotation speed of the grinder can be 150-450 rpm, preferably 200-400 rpm. The grinding time can be 0.5 to 2 hours, preferably 0.8 to 1.2 hours.

In the present invention, the magnetic separation or demagnetization equipment is not particularly limited as long as the magnetic impurities can be removed. In some specific embodiments of the present invention, for simplicity of operation, during the process of sending the grinding slurry to the filtering device, demagnetization is performed through a pipeline demagnetizer. The magnetic field intensity during the demagnetization process is not particularly limited, but may be about 12,000 Gauss, for example.

The above-mentioned preparation of suspension with acid and grinding and demagnetization steps are key steps to remove impurities. Of course, grinding also has an effect on particle size and spheroidization. If the iron oxide powder is soaked in acid to form a suspension without grinding and dispersion, the impurities will be wrapped in large particles and cannot be removed quickly. If you just use pure water to soak and grind to disperse, water-insoluble impurities such as aluminum, titanium, zinc, copper, etc. cannot be effectively removed.

Crude product preparation steps

In the embodiment of the present invention, after the demagnetization grinding slurry is prepared, it is filtered, washed, and dried to obtain crude iron oxide red product.

In specific embodiments of the present invention, filtration may be filtration using a chamber filter press. The cleaning process can be multiple times of washing, such as 2 to 5 times. The water consumption each time can be 40 to 60% of the dry weight of the iron oxide powder. The total water consumption can be 1 to 3 times the dry weight of the iron oxide powder, thereby obtaining Iron oxide red filter cake with a moisture content of 20 to 35% by mass.

In some specific embodiments of the present invention, in order to reduce impurities in iron oxide red and increase the iron oxide content, the water used in the cleaning process is pure water with a conductivity of 10 megaohms.

In the specific embodiment of the present invention, the drying temperature of the iron oxide red filter cake is not particularly limited. For example, it can be 120 to 220°C, preferably 180 to 220°C. The degree of drying can be such that the moisture content of the filter cake is 0.8 mass% or less, preferably 0.5 mass% or less.

Spherization process steps

In the present invention, after the crude iron oxide red product is prepared, it is pulverized to perform a spheroidization process, thereby obtaining spherical iron oxide red powder as the product.

In some specific embodiments of the present invention, the pulverizing step includes coarsely pulverizing the crude iron oxide red product, and then finely pulverizing and spheroidizing the crude iron oxide red product by using a jet pulverizer. Among them, the grinder used in the coarse crushing step is not particularly limited, and grinders commonly used in this field can be used. Examples thereof include hammer grinders, turbine grinders, tooth grinders, knife grinders, and pressure grinding grinders. Machine, milling crusher, etc.

In the steps of fine crushing and spheroidization, the jet pulverizer used can be a disc jet pulverizer, a circulating jet pulverizer, a vulcanized bed jet pulverizer, etc.

The above two steps of grinding and jet milling have an impact on particle size spheroidization. If only grinding is carried out without air pulverization, the degree of sphericalization of the particle surface will not be high. On the other hand, if grinding is not performed but only jet milling is performed, the particle size will be too large and the uniformity of the particle size will be poor.

Example

The embodiments of the present invention will be described in detail below with reference to examples, but those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. If the specific conditions are not specified in the examples, the conditions should be carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not indicated, they are all conventional products that are commercially available. In the examples, "%" means "mass %" unless otherwise specified.

The test method of the present invention is described below.

(1) Particle size distribution test

The particle size distribution tests of the samples in the following examples of the present invention were all conducted using a BT-9300S laser particle size distribution analyzer (manufactured by Dandong Baite Instrument Co., Ltd.).

(2)Element content test

The element content test of the samples in the following examples of the present invention was carried out using an ICP7400 elemental analyzer (manufactured by Thermo Fisher Scientific (China) Co., Ltd.).

(3) Scanning electron microscope test

The morphology of the samples in the following examples of the present invention were all measured using an S4700 scanning electron microscope (manufactured by HITACHI, Japan).

Example 1

The particle size test data of iron oxide red powder produced by a steel plant are: D10=1.147μm, D50=13.42μm, D97=41.11μm, and the average volume particle size is 14.73μm. Its specific surface area is 618.9m ² /kg. The specific particle size distribution curve is shown in Figure 1A.

The detection data of each element content in iron oxide red powder are as follows:

Fe ₂ O ₃ ,% K Na Ca Mg Cu Mn Al Ti Zn Cl 98.5 29 ppm 1081ppm 386ppm 85ppm 85ppm 2112 ppm 276ppm 196 ppm 87 ppm 2450ppm

The iron oxide red product is prepared as follows.

1) During slow stirring, use an acid-resistant pump to add 21 kg of 96% concentrated sulfuric acid to 3969 kg of pure water, then add 10 kg of oxalic acid powder to dissolve to form a 0.75% dilute acid solution, and then add 20 kg of polyoxyethylene ether. Non-ionic surfactant OP-10, mix well and add 1 ton of the above iron oxide red powder, stir for 1 hour to form a slurry;

2) Pour the above slurry into a vertical sand mill, rotate at 200 rpm, and grind for 1 hour;

3) When the above-ground slurry is pumped to the filter press, the pipeline demagnetizer (QL-159050 and Foshan Qinli Magnetic Equipment Co., Ltd.) absorbs the magnetic substances in the iron oxide red;

4) Use a filter press to filter the ground slurry, clean the filter material with 2 tons of 10 megohm pure water, and obtain an iron oxide red filter cake with a moisture content of 27%;

5) Use a 30-meter-long belt dryer to dry the filter cake at 180°C until the moisture content is less than 0.5%, then use a hammer mill (PC400x300 type and Zhengzhou Yangke Machinery Co., Ltd.) to crush the crude iron oxide red product, and then The crude iron oxide red product was crushed using a disc airflow mill (STJ475, Yixing Qingxin Powder Machinery Co., Ltd.) to obtain a purified iron oxide red product with refined particles.

Particle size test data: D10=0.399μm, D50=0.708μm, D97=1.415μm, the volume average particle size is 0.761μm. Its specific surface area is 3463m ² /kg. The specific particle size distribution curve is shown in Figure 1B.

The detection data of each element content of the purified iron oxide red product are as follows:

Fe ₂ O ₃ ,% K Na Ca Mg Cu Mn Al Ti Zn Cl 99.30 4 ppm 83ppm 41 ppm 19ppm 25ppm 1369 ppm 82ppm 48ppm 25ppm 852ppm

From the comparison of the above data, it can be seen that compared with the iron oxide red powder used as raw material, the purified iron oxide red product has a significantly reduced particle size, an increased specific surface area, a significantly reduced impurity content, and an increased iron oxide content.

In addition, it can be seen from the electron microscope photos shown in Figure 4B and Figure 4A that after the production process of increasing the iron oxide content and particle spheroidization in iron oxide red of the present invention, the particles of iron oxide red are more spherical and uniform. and miniaturization.

Example 2

The particle size test data of iron oxide red powder produced by a steel plant is: D10=1.077μm, D50=17.35μm, D97=55.49μm, and the average volume particle size is 19.90μm. Its specific surface area is 618.2m ² /kg. The specific particle size distribution curve is shown in Figure 2A.

The detection data of each element content in iron oxide red powder are as follows:

Fe ₂ O ₃ ,% K Na Ca Mg Cu Mn Al Ti Zn Cl 98.06 21 ppm 932ppm 338ppm 85ppm 64ppm 1930ppm 1233ppm 921 ppm 94ppm 1720ppm

The iron oxide red product is prepared as follows.

1) While stirring slowly, use an acid-resistant pump to add 50 kg of 65% concentrated nitric acid to 3930 kg of pure water, then add 20 kg of oxalic acid powder to dissolve to form a 1.3% dilute acid solution, then add 40 kg of polyol-type non-ionic acid. Ionic surfactant polyethylene glycol 600, mix well and then add 1 ton of the above iron oxide red powder and stir for 1 hour to form a slurry;

2) Pour the above slurry into a vertical sand mill, rotate at 300 rpm, and grind for 1 hour;

3) When the above ground slurry is pumped to the filter press, the pipeline demagnetizer absorbs the magnetic substances in the iron oxide red;

4) Use a filter press to filter the ground slurry, clean the filter material with 2 tons of 10 megohm pure water, and obtain an iron oxide red filter cake with a moisture content of 29%;

5) Use a 30-meter-long belt dryer to dry the filter cake at 200°C until the moisture content is less than 0.3%, then use a hammer mill to crush the crude iron oxide red product, and then use a disc airflow pulverizer to crush the crude iron oxide red product A purified iron oxide red product with refined particles is obtained.

Particle size test data: D10=0.315μm, D50=0.677μm, D97=1.307μm, the volume average particle size is 0.703μm. Its specific surface area is 3778m ² /kg. The specific particle size distribution curve is shown in Figure 2B.

The detection data of each element content of the purified iron oxide red product are as follows:

Fe ₂ O ₃ ,% K Na Ca Mg Cu Mn Al Ti Zn Cl 98.92 2ppm 41ppm 22ppm 11 ppm 33 ppm 823ppm 624ppm 57ppm 15ppm 676ppm

From the comparison of the above data, it can be seen that compared with the iron oxide red powder used as raw material, the purified iron oxide red product has a significantly reduced particle size, an increased specific surface area, a significantly reduced impurity content, and an increased iron oxide content.

Example 3

The particle size test data of iron oxide red powder produced by a pigment factory are: D10=0.276μm, D50=0.589μm, D97=1.048μm, and the volume average particle size is 0.579μm. Its specific surface area is 4633m ² /kg. The specific particle size distribution curve is shown in Figure 3A.

The detection data of each element content in iron oxide red powder are as follows:

Fe ₂ O ₃ ,% K Na Ca Mg Cu Mn Al Ti Zn Cl 96.32 19ppm 432ppm 514ppm 218ppm 42 ppm 31ppm 711ppm 1621ppm 652ppm 22ppm

The iron oxide red product is prepared as follows.

1) During slow stirring, use an acid-resistant pump to add 21 kg of 96% concentrated sulfuric acid to 3969 kg of pure water, then add 10 kg of 99.5% glacial acetic acid to form a 0.75% dilute acid solution, then add 30 kg of alcohol ester. Tween 40, a non-ionic surfactant, stir well and then add 1 ton of the above iron oxide red powder and stir for 1 hour to form a slurry;

2) Pour the above slurry into a vertical sand mill, rotate at 400 rpm, and grind for 1 hour;

3) When the above ground slurry is pumped to the filter press, the pipeline demagnetizer absorbs the magnetic substances in the iron oxide red;

4) Use a filter press to filter the ground slurry, clean the filter material with 2 tons of 10 megohm pure water, and obtain an iron oxide red filter cake with a moisture content of 34%;

5) Use a 30-meter-long belt dryer to dry the filter cake at 220°C until the moisture content is less than 0.3%, then use a hammer mill to crush the crude iron oxide red product, and then use a disc airflow pulverizer to crush the crude iron oxide red product to D50 = 0.44 μm, and a purified iron oxide red product with refined particles is obtained.

Particle size test data: D10=0.225μm, D50=0.319μm, D97=0.865μm, the volume average particle size is 0.418μm. Its specific surface area is 6506m ² /kg. The specific particle size distribution curve is shown in Figure 3B.

The detection data of each element content of the purified iron oxide red product are as follows:

Fe ₂ O ₃ ,% K Na Ca Mg Cu Mn Al Ti Zn Cl 98.29 <1ppm 44 ppm 33ppm 32 ppm 23ppm 26ppm 59ppm 86ppm 38 ppm 5 ppm

From the comparison of the above data, it can be seen that compared with the iron oxide red powder used as raw material, the purified iron oxide red product has reduced particle size, increased specific surface area, greatly reduced impurity content, and increased iron oxide content.

Comparative example 1

The other conditions were the same as in Example 1 except that only pure water was used to prepare the slurry without acid. The detection data of each element content of the obtained iron oxide red product are as follows:

Fe ₂ O ₃ ,% K Na Ca Mg Cu Mn Al Ti Zn Cl 98.6 13 ppm 577ppm 214 ppm 54ppm 82ppm 2036ppm 289 ppm 185ppm 81ppm 1138ppm

It can be seen from the data in the table that the iron oxide purity of this product is not improved very much, and the amount of impurities removed is very small.

Comparative example 2

The conditions were the same as in Example 2 except that only pure water was used to prepare the slurry without acid. The detection data of each element content of the obtained iron oxide red product are as follows:

Fe ₂ O ₃ ,% K Na Ca Mg Cu Mn Al Ti Zn Cl 98.11 6ppm 217 ppm 275ppm 59ppm 62ppm 1948 ppm 1193ppm 945ppm 88ppm 654 ppm

It can be seen from the data in the table that the iron oxide purity of this product is not improved very much, and the amount of impurities removed is very small.

Comparative example 3

The conditions were the same as in Example 3 except that only pure water was used to prepare the slurry without acid. The detection data of each element content of the obtained iron oxide red product are as follows:

Fe ₂ O ₃ ,% K Na Ca Mg Cu Mn Al Ti Zn Cl 96.19 8 ppm 129 ppm 378ppm 141ppm 44 ppm 34 ppm 697ppm 1643ppm 643ppm 12ppm

It can be seen from the data in the table that the iron oxide purity of this product not only does not increase, but also decreases, and the amount of impurities removed is very small.

Comparing Examples 1 to 3 with Examples 1 to 3 respectively, it can be seen that impurities cannot be effectively removed using only pure water without using acid.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified. Modifications or equivalent substitutions without departing from the spirit and scope of the technical solution of the present invention shall be included in the scope of the claims of the present invention.

Industrial availability

Compared with the iron oxide red produced by existing steel plants or pigment factories, the present invention has the advantages of higher purity, lower impurity content, smaller particle size, high spheroidization and large specific surface area, and the preparation method of the present invention is simple. , low cost, low energy consumption, large output, suitable for industrial large-scale production.

Claims (10)

1. An iron oxide red powder containing 98.0% by mass or more of Fe ₂ O ₃ and containing K, Na, Ca, Mg, Zn, Cu, and Ti each in an amount of 0.01% by mass or less, The iron oxide red has a substantially spherical shape and a median particle diameter D50 of 0.2 μm to 1.0 μm. 2. The iron oxide red powder according to claim 1, wherein the content of K is 15 ppm or less, preferably 10 ppm or less; and/or the Na content is 95 ppm or less, preferably 85 ppm or less; and/or the Ca content is 80 ppm. and/or the Mg content is 60 ppm or less, preferably 40 ppm or less; and/or the Zn content is 65 ppm or less, preferably 45 ppm or less; and/or the Cu content is 60 ppm or less, preferably 40 ppm or less. ; and/or, the Ti content is 90 ppm or less, preferably 86 ppm or less. 3. The iron oxide red powder according to claim 1 or 2, which further contains Mn in a content of 0.18 mass% or less, preferably 0.15 mass% or less; and/or further contains Mn in a content of 0.1 mass% or less, preferably 0.08 mass%. % or less of Al; and/or it also contains Cl in a content of 0.1% by mass or less. 4. The iron oxide red powder according to any one of claims 1 to 3, wherein the median particle diameter D50 of the iron oxide red powder is 0.3 μm ~ 0.8 μm; and/or, the iron oxide red powder has D10 is 0.1 μm to 0.5 μm, and D97 is 0.8 μm to 1.5 μm; and/or the volume average particle size of the iron oxide red powder is 0.3 to 0.9 μm; and/or the specific surface area of the iron oxide red powder is It is above 2000m ² /kg. 5. A preparation method of iron oxide red powder according to any one of claims 1-4, which includes the following steps: A suspension preparation step of mixing a dilute acid solution, a dispersant and iron oxide red powder to obtain an iron oxide red suspension; The obtained suspension is ground to obtain a grinding slurry, and then the grinding and demagnetization step is performed to obtain a demagnetized grinding slurry; The preparation steps of filtering, cleaning and drying the demagnetized grinding slurry to obtain crude iron oxide red crude product; and A spheroidizing step of pulverizing the crude iron oxide red product to obtain spherical iron oxide red powder as the product. 6. The preparation method according to claim 5, wherein the dilute acid is one of sulfuric acid, nitric acid, formic acid, acetic acid, carbonic acid, oxalic acid, citric acid, malic acid, tartaric acid, succinic acid, benzoic acid, and salicylic acid. One or more kinds; and/or, the concentration of the dilute acid solution is 0.2 to 2.0 mass%. 7. The preparation method according to claim 5 or 6, wherein the dispersant is a nonionic surfactant, and the nonionic surfactant includes polyoxyethylene ethers, polyols, polyol esters, One or more of the amide types; and/or the polyoxyethylene ethers include one or more of alkylphenol polyoxyethylene ethers, fatty alcohol polyoxyethylene ethers, and fatty acid polyoxyethylene ethers; And/or, the polyols include one or more of polyethylene glycol 200, polyethylene glycol 400, polyethylene glycol 600, polypropylene glycol, and polybutylene glycol; and/or, the polyols Alcohol esters include one or more of Tween 20, Tween 40, Tween 60, and Tween 80; and/or, the amide type includes stearic acid diethanolamide, cocoacid diethanolamide, One or more types of coco acid monoethanolamide. 8. The preparation method according to any one of claims 5 to 7, wherein the proportion of the dispersant in the iron oxide red suspension is 0.2 to 2.0 mass%; and/or the iron oxide red powder The proportion in the iron oxide red suspension is 40 to 80 mass%. 9. The preparation method according to any one of claims 5 to 8, wherein the demagnetization is performed by passing through a pipeline demagnetizer during the process of sending the grinding slurry to the filtering device; and/or, the cleaning is performed by using Conducted with pure water with a conductivity of 10 megohms. 10. The preparation method according to any one of claims 5 to 9, wherein the spheroidization step includes coarsely crushing the crude iron oxide red product, and then finely crushing and spheroidizing the crude iron oxide red product by using a jet pulverizer, thereby obtaining The product is spherical iron oxide red powder.