阅读说明：本技术 一种无氯低钠硫酸钡的制备方法 (Preparation method of chlorine-free low-sodium barium sulfate ) 是由 刘湘玉 华东 严家铎 蒋友良 常晓璇 于甜甜 申亚楠 于 2019-10-16 设计创作，主要内容包括：本发明属于精细无机化工制备技术领域,涉及一种无氯低钠硫酸钡的制备方法,包括(1)按照[SO<Sub>4</Sub><Sup>2-</Sup>]:[Ba<Sup>2+</Sup>]为1:(1～1.2)的比例分别配制氢氧化钡溶液和硫酸锂溶液；(2)制备硫酸钡粗品控制滴加速度将所述氢氧化钡溶液和所述硫酸锂溶液进行并流沉淀反应,反应温度为25～40℃,陈化后经过滤分离得到硫酸钡粗品；(3)提纯对所述硫酸钡粗品进行洗涤,固液分离,经干燥得到硫酸钡产品。本发明的无氯低钠硫酸钡的制备方法工艺简单、成本低、原材料容易获得,因此,本发明适于工业化生产。(The invention belongs to the technical field of fine inorganic chemical preparation, and relates to a preparation method of chlorine-free low-sodium barium sulfate, which comprises the following steps of (1) preparing according to [ SO ] 4 2‑ ]:[Ba 2+ ]1, (1-1.2) respectively preparing a barium hydroxide solution and a lithium sulfate solution; (2) preparing a crude barium sulfate product, controlling the dropping speed, carrying out parallel-flow precipitation reaction on the barium hydroxide solution and the lithium sulfate solution at the reaction temperature of 25-40 ℃, and aging and then filtering and separating to obtain the crude barium sulfate product; (3) and purifying to wash the crude barium sulfate product, performing solid-liquid separation, and drying to obtain a barium sulfate product. The preparation method of the chlorine-free low-sodium barium sulfate has the advantages of simple process, low cost and easily obtained raw materials, so the method is suitable for industrial production.)

1. A preparation method of chlorine-free low-sodium barium sulfate is characterized by comprising the following steps:

(1) preparing a reaction solution

According to [ SO ]₄ ^2-]:[Ba²⁺]Respectively preparing a barium hydroxide solution and sulfuric acid according to the proportion of 1 (1-1.2)A lithium solution;

(2) preparation of crude barium sulfate

Controlling the dropping speed to enable the barium hydroxide solution and the lithium sulfate solution to perform parallel-flow precipitation reaction at the reaction temperature of 25-40 ℃, and aging and then filtering and separating to obtain a crude barium sulfate product;

(3) purification of

And washing the crude barium sulfate product, carrying out solid-liquid separation, and drying to obtain a barium sulfate product.

2. The method for preparing chlorine-free low-sodium barium sulfate according to claim 1, wherein the dropping rate of the barium hydroxide solution is 0.5 to 1L/h, and the dropping rate of the lithium sulfate solution is 0.05 to 0.1L/h.

3. The method for preparing chlorine-free low-sodium barium sulfate according to claim 2, wherein the dropping rate of the barium hydroxide solution is 1L/h, and the dropping rate of the lithium sulfate solution is 0.1L/h.

4. The method for preparing chlorine-free low-sodium barium sulfate according to claim 1, wherein the reaction temperature of the cocurrent precipitation reaction is 25-35 ℃.

5. The method for preparing chlorine-free low-sodium barium sulfate according to claim 1, wherein the aging temperature is 20-35 ℃ and the aging time is 0.5-3 h.

6. The method of claim 1, wherein the drying is performed in a vacuum oven.

7. The method for preparing chlorine-free low-sodium barium sulfate according to claim 6, wherein the temperature of the vacuum drying oven is 80-90 ℃.

8. A chlorine-free low-sodium barium sulfate, which is prepared by the method for preparing chlorine-free low-sodium barium sulfate according to any one of claims 1 to 7.

9. The chlorine-free low-sodium barium sulfate of claim 8, wherein the particle size D of the chlorine-free low-sodium barium sulfate is₅₀From 0.2 microns to 0.7 microns.

Technical Field

The invention belongs to the technical field of fine inorganic chemical preparation, and relates to a preparation method of chlorine-free low-sodium barium sulfate.

Background

The lithium ion battery consists of a positive electrode material, a negative electrode material, electrolyte, a diaphragm and a battery shell. The separator is one of the key internal layer components in a lithium ion battery as the "third pole" of the battery. The performance of the separator determines the capacity, internal resistance and cycle performance of the lithium ion battery to a great extent. Currently, the separator used in many cases is a polyolefin microporous membrane, such as a polypropylene membrane, a polyethylene membrane, or a multi-layer composite membrane of the two. The polyolefin microporous membrane is excellent in mechanical strength and chemical stability, but when the temperature reaches 130 ℃ or higher, thermal shrinkage occurs, causing short circuit in the battery and possibly causing thermal runaway. The surface of the polyolefin diaphragm is hydrophobic, and the wettability of the electrolyte is poor, so that the internal resistance of the battery can be increased, and the cycle performance and the charge-discharge efficiency are not improved.

The diaphragm can be modified by various physical and chemical methods, and the high-temperature-resistant inorganic nano particles are coated on the surface of the diaphragm to enhance the dimensional stability and the wettability, so that the method is simple and convenient. Common inorganic nanoparticles are Al₂O₃、SiO₂、TiO₂、ZrO₂And the like. However, the application of nanoparticles is limited by the problems of high production cost, large particle size, difficult uniform dispersion and the like.

Barium sulfate is an important inorganic chemical raw material, has good chemical stability, and the raw material for preparing barium sulfate has rich sources and lower cost, so that the barium sulfate has very wide application prospect. The traditional preparation method of barium sulfate comprises barium sulfate preparation by barium carbonate sulfuric acid method, barium sulfate preparation by yellow water sulfuric acid method and barium sulfate preparation by mirabilite method.

However, in order to meet the requirements of lithium ion battery separators, higher requirements are also put on barium sulfate, and if the barium sulfate contains chloride ions or high-content sodium ions, the migration of the chloride ions and the sodium ions affects the migration of lithium ions, so that the charge and discharge capacity of the battery is reduced. The barium sulfate prepared by the traditional barium sulfate preparation method has low purity and unreasonable particle size, and cannot meet the requirements, so that the field needs to provide a preparation method of high-purity barium sulfate.

Disclosure of Invention

The invention aims to provide a preparation method of chlorine-free low-sodium barium sulfate aiming at the defects of the prior art.

Specifically, the preparation method of the chlorine-free low-sodium barium sulfate comprises the following steps:

(1) preparing a reaction solution

According to [ SO ]₄ ^2-]:[Ba²⁺]1, (1-1.2) respectively preparing a barium hydroxide solution and a lithium sulfate solution;

(2) preparation of crude barium sulfate

Controlling the dropping speed to enable the barium hydroxide solution and the lithium sulfate solution to be in parallel flow and drop into a base solution for precipitation reaction, wherein the reaction temperature is 25-40 ℃, and filtering and separating after aging to obtain a crude barium sulfate product;

(3) purification of

And washing the crude barium sulfate product, carrying out solid-liquid separation, and drying to obtain a barium sulfate product.

According to the preparation method of the chlorine-free low-sodium barium sulfate, the dropping speed of the barium hydroxide solution is 0.5-1L/h, and the dropping speed of the lithium sulfate solution is 0.05-0.1L/h.

In the preparation method of the chlorine-free low-sodium barium sulfate, the dropping speed of the barium hydroxide solution is 1L/h, and the dropping speed of the lithium sulfate solution is 0.1L/h.

In the preparation method of the chlorine-free low-sodium barium sulfate, the reaction temperature of the cocurrent precipitation reaction is 25-35 ℃.

According to the preparation method of the chlorine-free low-sodium barium sulfate, the aging temperature is 20-35 ℃, and the aging time is 0.5-3 hours.

In the preparation method of the chlorine-free low-sodium barium sulfate, the drying is carried out in a vacuum drying oven.

In the preparation method of the chlorine-free low-sodium barium sulfate, the temperature of the vacuum drying oven is 80-90 ℃.

In another aspect, the invention provides chlorine-free low-sodium barium sulfate, which is prepared by the preparation method of the chlorine-free low-sodium barium sulfate.

Preferably, the particle diameter D of the chlorine-free low-sodium barium sulfate₅₀From 0.2 microns to 0.7 microns.

The technical scheme of the invention has the following beneficial effects:

(1) the preparation method of the chlorine-free low-sodium barium sulfate has the advantages of simple process, low cost and easily obtained raw materials, so the method is suitable for industrial production;

(2) the barium sulfate product has the advantages of high purity, high whiteness, reasonable particle size, no chlorine element and low sodium content, and meets the requirement of a lithium ion battery diaphragm on barium sulfate;

(3) d obtained by the preparation method of the chlorine-free low-sodium barium sulfate₅₀Barium sulfate product of 0.2 micron suitable for resin compounding, D₅₀The 0.7 micron barium sulfate product is suitable for surface coating of battery separators.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention.

FIG. 1 is a process flow diagram of the preparation method of chlorine-free low-sodium barium sulfate of the present invention.

Detailed Description

The present invention will be described in detail with reference to the following embodiments in order to fully understand the objects, features and effects of the invention. The process of the present invention employs conventional methods or apparatus in the art, except as described below. The following noun terms have meanings commonly understood by those skilled in the art unless otherwise specified.

The invention adopts lithium sulfate and barium hydroxide to carry out composite decomposition reaction, and produces BaSO by utilizing lithium-barium combination technology₄The sodium content is low and chlorine is not contained, and LiOH can be used as a byproduct. The invention mainly relates to the following chemical reactions:

Ba(OH)₂+Li₂SO₄＝BaSO₄↓+2LiOH

specifically, as shown in fig. 1, the preparation method of the chlorine-free low-sodium barium sulfate of the present invention comprises the following steps:

(1) preparing a reaction solution

According to [ SO ]₄ ^2-]:[Ba²⁺]1, (1-1.2) respectively preparing a barium hydroxide solution and a lithium sulfate solution;

wherein, [ SO ]₄ ^2-]Indicates the concentration of sulfate ion, [ Ba ]²⁺]Indicates the concentration of barium ions.

In some embodiments, the barium hydroxide may be Ba (OH)₂.8H₂O; in still other embodiments, the barium hydroxide may be barium hydroxide without crystal water, and the present invention is not limited thereto.

(2) Preparation of crude barium sulfate

And (3) controlling the flow rate to perform cocurrent flow precipitation reaction on the barium hydroxide solution and the lithium sulfate solution, wherein the reaction temperature is 25-40 ℃ (preferably 25-35 ℃), stopping the reaction when no new solid is generated in the solution, and then aging and filtering to separate to obtain a crude barium sulfate product.

Wherein the dropping speed of the barium hydroxide solution is 0.5L/h-1L/h, and the dropping speed of the lithium sulfate solution is 0.05L/h-0.1L/h.

In some preferred embodiments, the dropping rate of the barium hydroxide solution is 1L/h, and the dropping rate of the lithium sulfate solution is 0.1L/h.

The cocurrent flow precipitation reaction is carried out in a cocurrent flow synthesis reactor, and the cocurrent flow synthesis reactor can ensure that barium hydroxide and lithium sulfate react more fully in cocurrent flow and reduce the coating of impurities in barium sulfate.

According to the invention, the reaction temperature and the dropping speed are controlled within the above range, so that the generation rate of barium sulfate can be limited, impurities in the solution can be prevented from being occluded in barium sulfate solid due to overhigh generation rate of barium sulfate, the particle size of barium sulfate solid caused by overhigh generation rate of barium sulfate can be prevented from being too large, and the purity and the particle size of the generated barium sulfate are further optimized.

In the present invention, aging means that after precipitation, the nascent precipitate and the mother liquor are allowed to stand for a period of time, and this process is also called aging.

In some preferred embodiments, the aging temperature is 20-35 ℃, the aging time is 0.5-3 h, and in the process, impurities adsorbed, occluded and occluded in barium sulfate precipitates enter the solution again along with the dissolution of the small barium sulfate grains, so that the purity of the barium sulfate product is improved.

(3) Purification of

And washing the crude barium sulfate product, carrying out solid-liquid separation, and drying to obtain a barium sulfate product.

Wherein the washing comprises washing the crude barium sulfate product with distilled water for a plurality of times.

Wherein the solid-liquid separation operation is a method commonly used in the art, and the invention is not particularly limited herein.

In some preferred embodiments, the drying is carried out in a vacuum drying oven, wherein the temperature of the vacuum drying oven is 80 to 90 ℃, preferably 85 ℃.

In some more preferred embodiments, in order to accelerate the drying speed of barium sulfate, a container containing a drying agent, including but not limited to phosphorus pentoxide, can be added to the vacuum drying oven.

The preparation method of the chlorine-free low-sodium barium sulfate has the advantages of simple process, low cost and easily obtained raw materials, so the preparation method of the chlorine-free low-sodium barium sulfate is suitable for industrial production.

In another aspect, the invention provides a chlorine-free low-sodium barium sulfate, which is prepared by the preparation method of the chlorine-free low-sodium barium sulfate.

D obtained by the preparation method of the chlorine-free low-sodium barium sulfate₅₀Barium sulfate product of 0.2 micron suitable for resin compounding, D₅₀The 0.7 micron barium sulfate product is suitable for surface coating of battery separators.

In the field, the paper-based copper clad laminate is a product obtained by laminating a paper base and a copper foil together by using epoxy resin and the like as a fluxing agent and is a direct raw material of a PCB (printed circuit board). The barium sulfate is used as a filler to be mixed with the resin, so that the using amount of the resin can be effectively reduced, and the cost can be reduced because the price of the resin is far higher than that of the barium sulfate. In addition, the smaller the barium sulfate particle size is, the thinner the thickness of the substrate is, and further the performance of the copper-clad plate can be improved.

The chlorine-free low-sodium barium sulfate product obtained by the invention has the advantages of high purity, high whiteness value, reasonable particle size, no chlorine element and low sodium content, and meets the requirement of the lithium ion battery diaphragm on barium sulfate.