阅读说明：本技术 一种无水氢氧化锂的离心喷雾干燥制备方法 (Centrifugal spray drying preparation method of anhydrous lithium hydroxide ) 是由 吴文斌 丁海云 孙雪云 龚明明 郭国龙 苗强 王春叶 杜桂荣 周京霞 陈琳 熊国 于 2019-11-18 设计创作，主要内容包括：本发明属于化学物质制备技术领域,具体涉及一种无水氢氧化锂的离心喷雾干燥制备方法。本发明技术方案中,在氮气保护下,将加入杂质的一水氢氧化锂(<Sup>7</Sup>LiOH)通过喷雾离心干燥、冷凝分离,将水分去除,制备得到纳米无水氢氧化锂(<Sup>7</Sup>LiOH)粉末,所加入的杂质在粉末中分布均匀,该氢氧化锂(<Sup>7</Sup>LiOH)粉末杂质分布均匀,经系统检测核验后用作氢氧化锂(<Sup>7</Sup>LiOH)标准物质。(The invention belongs to the technical field of chemical substance preparation, and particularly relates to a centrifugal spray drying preparation method of anhydrous lithium hydroxide. In the technical scheme of the invention, under the protection of nitrogen, lithium hydroxide monohydrate (lithium hydroxide) added with impurities 7 LiOH is subjected to spray centrifugal drying and condensation separation to remove water, and the nano anhydrous lithium hydroxide (A), (B) is prepared 7 LiOH) powder in which the added impurities are distributed homogeneously, the lithium hydroxide 7 LiOH) powder has uniform impurity distribution, and can be used as lithium hydroxide (lithium hydroxide) after system detection and verification 7 LiOH) standard substance.)

1. A centrifugal spray drying preparation method of anhydrous lithium hydroxide is characterized by comprising the following steps:

(1) determining a preparation system

(2) Determination of specific Process steps

① dissolving high-purity lithium hydroxide monohydrate and impurities in a plastic barrel by using deionized water at room temperature to form a mixed solution containing lithium hydroxide and impurities;

② sucking the mixed liquid by peristaltic pump into high-speed centrifugal atomizer at the top of the drying tower, and blowing the nitrogen heated by electric heater into the high-speed centrifugal atomizer;

③ under the action of centrifugal force, the mixed liquid in the atomizer forms a fog group and is sprayed out from the spray holes of the atomizing disk;

④ under the drive of nitrogen in step (2) ②, the water in the fog group in step (2) ③ is evaporated to dryness quickly to form dry powder;

⑤ collecting the dry powder formed in ④ of the step (2) by sucking the dry powder into a bag collector through a discharge pipe;

⑥ the nitrogen containing water vapor enters the condenser, wherein the water vapor is condensed into water to be discharged, and the nitrogen enters the heating device again through the pipeline by the exhaust fan to realize circulation.

2. The method according to claim 1, wherein the centrifugal spray-drying process comprises the steps of: in the step (1), each part of the preparation system is as follows:

the peristaltic pump is connected with the atomizer through a silicone tube;

the atomizer is arranged at the upper part of the drying tower and is connected with the drying tower;

the electric heater is arranged on the side of the drying tower;

conveying the nitrogen heated by the electric heater into a drying tower through a hot air distributor;

the lower outlet of the drying tower is connected with the filter bag separator through a pipeline;

gas-solid separation is realized in the filter bag separator;

the lower part of the filter bag separator is provided with a product collecting tank;

the upper part of the filter bag separator is connected with the top of the condenser through a pipeline, and nitrogen and water vapor enter the condenser through the pipeline;

the condensed water enters a solvent collector at the lower end of the condenser and is discharged through a discharge port, and the condensed nitrogen is recycled by an exhaust fan.

3. The method according to claim 1, wherein the impurities in step (2) ① include Ca, Pb, Zn, Cl, F^-、SO₄ ^2-。

4. The method according to claim 3, wherein the impurities are added to the high purity lithium hydroxide monohydrate in step (2) ① in the form of Ca (NO) as an impurity₃)₂、Pb(NO₃)₂、Zn(NO₃)₂、HCl、HF、H₂SO₄。

5. The method according to claim 4, wherein in step (2) ①, the impurities Ca, Pb, and Zn are 10-500 mg/kg lithium hydroxide and Cl and F/kg lithium hydroxide^-、SO₄ ^2-All 50-1000 mg.

6. The method according to claim 3, wherein in step (2) ②, the mixture is sucked into a high-speed centrifugal atomizer at the top of the drying tower by a peristaltic pump, and nitrogen heated to 180-300 ℃ by an electric heater is blown into the high-speed centrifugal atomizer.

7. The method for preparing anhydrous lithium hydroxide by centrifugal spray drying according to claim 3, wherein the flow rate of nitrogen gas in the step (2) ② is 1 to 3Nm³The pressure of nitrogen is 1-3 kPa.

8. The method according to claim 3, wherein the centrifugal force of step (2) ③ is provided by a centrifugal plate rotating at 10000-20000 rpm.

9. The method according to claim 1, wherein the centrifugal spray-drying process comprises the steps of: in the step (1), each part of the preparation system is as follows:

the peristaltic pump is connected with the atomizer through a silicone tube;

the atomizer is arranged at the upper part of the drying tower and is connected with the drying tower;

the electric heater is arranged on the side of the drying tower;

conveying the nitrogen heated by the electric heater into a drying tower through a hot air distributor;

the lower outlet of the drying tower is connected with the filter bag separator through a pipeline;

gas-solid separation is realized in the filter bag separator;

the lower part of the filter bag separator is provided with a product collecting tank;

the upper part of the filter bag separator is connected with the top of the condenser through a pipeline, and nitrogen and water vapor enter the condenser through the pipeline;

the condensed water enters a solvent collector at the lower end of the condenser and is discharged through a discharge port, and the condensed nitrogen is recycled by an exhaust fan;

in the step (2) ①, the impurities include Ca, Pb, Zn, Cl and F^-、SO₄ ^2-(ii) a General purpose impurity removerAdded to the high purity lithium hydroxide monohydrate in the following form: ca (NO)₃)₂、Pb(NO₃)₂、Zn(NO₃)₂、HCl、HF、H₂SO₄(ii) a Each kilogram of lithium hydroxide is added with 10-500 mg of impurities of Ca, Pb and Zn; adding Cl and F to each kilogram of lithium hydroxide^-、SO₄ ^2-50-1000 mg;

in the step (2) ②, sucking the mixed solution into a high-speed centrifugal atomizer at the top of a drying tower by a peristaltic pump, and simultaneously blowing nitrogen heated to 180-300 ℃ by an electric heater into the high-speed centrifugal atomizer;

in the step (2) ②, the flow rate of nitrogen is 1-3 Nm³The pressure of nitrogen is 1-3 kPa;

in the step (2) ③, centrifugal force is provided by a centrifugal disc with rotation speed of 10000-20000 rpm.

Technical Field

The invention belongs to the technical field of chemical substance preparation, and particularly relates to a centrifugal spray drying preparation method of anhydrous lithium hydroxide.

Background

Lithium hydroxide for nuclear power⁷LiOH) is enriched in lithium⁷Li(⁷Li/Total Li>99.9%) due to⁷Li has the smallest neutron cross-section, so lithium hydroxide (7LiOH) is used to adjust the pH of the primary water of the pressurized water reactor. The pressurized water reactor uses water as a primary coolant, circulates in a high-temperature high-pressure and strong radiation field, and carries out a series of reactions besides heat carrying and moderating neutrons: neutron activation reactions of water and impurities therein, radiolytic decomposition of water, corrosion of materials by water and activation, migration and deposition of corrosion products, escape of fission products from damaged fuel elements and their transfer with coolant, etc. Although the surfaces of the equipment and the pipeline of the primary loop coolant system are made of stainless steel materials, oxygen or other harmful substances contained in water can corrode the materials, the service life of the equipment is shortened, and solid corrosion products become new radiation sources after being irradiated by neutrons. The pH value in the coolant has great influence on the corrosion rate of the material, and the corrosion rate of the stainless steel material is the lowest when water is in weak alkalinity. By controlling lithium hydroxide⁷The content of LiOH is used for adjusting the alkalescence of water so as to avoid or reduce the corrosion of materials, and lithium hydroxide⁷LiOH) has strict index requirements on impurities in the product. To ensure nuclear pure lithium hydroxide (⁷The accuracy of analysis and test results of various impurity elements in the LiOH) application process needs to develop lithium hydroxide (LiOH)⁷LiOH) (abundant Li-7) standard substance, nuclear pure lithium hydroxide (II)⁷LiOH) production application process and analytical process.

And currently there is no anhydrous lithium hydroxide (⁷LiOH), there is a need to develop a centrifugal spray-drying preparation method of anhydrous lithium hydroxide, thereby solving the above problems.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a centrifugal spray drying preparation method of anhydrous lithium hydroxide so as to meet the requirement of lithium hydroxide⁷The requirements of quantity transmission, evaluation analysis method, personnel assessment and the like for detecting impurity elements in LiOH) ensure that lithium hydroxide (lithium hydroxide)⁷LiOH) quality of the product.

In order to realize the purpose, the invention adopts the technical scheme that:

a centrifugal spray drying preparation method of anhydrous lithium hydroxide comprises the following steps:

(1) determining a preparation system

(2) Determination of specific Process steps

① dissolving high-purity lithium hydroxide monohydrate and impurities in a plastic barrel by using deionized water at room temperature to form a mixed solution containing lithium hydroxide and impurities;

② sucking the mixed liquid by peristaltic pump into high-speed centrifugal atomizer at the top of the drying tower, and blowing the nitrogen heated by electric heater into the high-speed centrifugal atomizer;

③ under the action of centrifugal force, the mixed liquid in the atomizer forms a fog group and is sprayed out from the spray holes of the atomizing disk;

④ under the drive of nitrogen in step (2) ②, the water in the fog group in step (2) ③ is evaporated to dryness quickly to form dry powder;

⑤ collecting the dry powder formed in ④ of the step (2) by sucking the dry powder into a bag collector through a discharge pipe;

⑥ the nitrogen containing water vapor enters the condenser, wherein the water vapor is condensed into water to be discharged, and the nitrogen enters the heating device again through the pipeline by the exhaust fan to realize circulation.

Further, in the above-mentioned centrifugal spray-drying preparation method of anhydrous lithium hydroxide, in the step (1), the components of the preparation system are specifically as follows:

the peristaltic pump is connected with the atomizer through a silicone tube;

the atomizer is arranged at the upper part of the drying tower and is connected with the drying tower;

the electric heater is arranged on the side of the drying tower;

conveying the nitrogen heated by the electric heater into a drying tower through a hot air distributor;

the lower outlet of the drying tower is connected with the filter bag separator through a pipeline;

gas-solid separation is realized in the filter bag separator;

the lower part of the filter bag separator is provided with a product collecting tank;

the upper part of the filter bag separator is connected with the top of the condenser through a pipeline, and nitrogen and water vapor enter the condenser through the pipeline;

the condensed water enters a solvent collector at the lower end of the condenser and is discharged through a discharge port, and the condensed nitrogen is recycled by an exhaust fan.

Further, in the above centrifugal spray-drying method for preparing anhydrous lithium hydroxide, in the step (2) ①, the impurities include Ca, Pb, Zn, Cl and F^-、SO₄ ^2-。

Further, in the above-mentioned centrifugal spray-drying process for preparing anhydrous lithium hydroxide, in step (2) ①, the impurities are added to the highly pure lithium hydroxide monohydrate in the form of Ca (NO)₃)₂、Pb(NO₃)₂、Zn(NO₃)₂、HCl、HF、H₂SO₄。

Further, the above-mentioned centrifugal spray-drying preparation method of anhydrous lithium hydroxide comprises the step (2) ①, wherein each kilogram of lithium hydroxide is added with 10-500 mg of impurities Ca, Pb and Zn, and each kilogram of lithium hydroxide is added with Cl and F^-、SO₄ ^2-All 50-1000 mg.

Further, in the above centrifugal spray drying preparation method of anhydrous lithium hydroxide, in step (2) ②, the mixed solution is sucked by a peristaltic pump into a high-speed centrifugal atomizer at the top of the drying tower, and nitrogen heated to 180 to 300 ℃ by an electric heater is blown into the high-speed centrifugal atomizer.

Further, the above-mentioned centrifugal spray-drying method for preparing anhydrous lithium hydroxide comprises the step (2) ② of supplying nitrogen gas at a flow rate of 1 to 3Nm³The pressure of nitrogen is 1-3 kPa.

Further, in the above centrifugal spray drying method for preparing anhydrous lithium hydroxide, in step (2) ③, the centrifugal force is provided by a centrifugal disc rotating at 10000-20000 rpm.

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

1) spray drying technique using nitrogen gas circulation protection from lithium hydroxide⁷The LiOH solution is directly prepared into anhydrous lithium hydroxide (lithium hydroxide) with similar chemical components in one step⁷LiOH) powder, to achieve different contents of impurity elements in anhydrous lithium hydroxide⁷LiOH) are uniformly distributed in the preparation process.

2) Can continuously complete anhydrous lithium hydroxide⁷LiOH) standard substance candidates, improving the working environment.

3) Breaks through the conventional method of preparing standard substances by physical pulverization.

Detailed Description

The technical solution of the present invention will be described in detail with reference to the following specific examples.

The invention relates to a centrifugal spray drying preparation method of anhydrous lithium hydroxide, which comprises the following steps:

(1) determining a preparation system

The components of the preparation system are as follows:

the peristaltic pump is connected with the atomizer through a silicone tube;

the atomizer is arranged at the upper part of the drying tower and is connected with the drying tower;

the electric heater is arranged on the side of the drying tower;

conveying the nitrogen heated by the electric heater into a drying tower through a hot air distributor;

the lower outlet of the drying tower is connected with the filter bag separator through a pipeline;

gas-solid separation is realized in the filter bag separator;

the lower part of the filter bag separator is provided with a product collecting tank;

the upper part of the filter bag separator is connected with the top of the condenser through a pipeline, and nitrogen and water vapor enter the condenser through the pipeline;

the condensed water enters a solvent collector at the lower end of the condenser and is discharged through a discharge port, and the condensed nitrogen is recycled by an exhaust fan;

(2) determination of specific Process steps

① dissolving high-purity lithium hydroxide monohydrate and impurities in a plastic barrel by using deionized water at room temperature to form a mixed solution containing lithium hydroxide and impurities;

the impurities include Ca, Pb, Zn, Cl, F^-、SO₄ ^2-；

The impurities are added to the high purity lithium hydroxide monohydrate by the following form: ca (NO)₃)₂、Pb(NO₃)₂、Zn(NO₃)₂、HCl、HF、H₂SO₄；

Each kilogram of lithium hydroxide is added with 10-500 mg of impurities of Ca, Pb and Zn; adding Cl and F to each kilogram of lithium hydroxide^-、SO₄ ^2-50-1000 mg;

② sucking the mixed liquid by a peristaltic pump into a high-speed centrifugal atomizer at the top of the drying tower, and blowing nitrogen heated to 180-300 ℃ by an electric heater into the high-speed centrifugal atomizer;

the flow rate of nitrogen is 1-3 Nm³The pressure of nitrogen is 1-3 kPa;

③ under the action of centrifugal force provided by a centrifugal disc with rotation speed of 10000-20000 rpm, the mixed liquid in the atomizer forms a fog group and is sprayed out from spray holes of the atomizing disc;

④ under the drive of nitrogen in step (2) ②, the water in the fog group in step (2) ③ is evaporated to dryness quickly to form dry powder;

⑤ collecting the dry powder formed in ④ of the step (2) by sucking the dry powder into a bag collector through a discharge pipe;

⑥ the nitrogen containing water vapor enters the condenser, wherein the water vapor is condensed into water to be discharged, and the nitrogen enters the heating device again through the pipeline by the exhaust fan to realize circulation.

In the technical scheme of the invention, under the protection of nitrogen, lithium hydroxide monohydrate (lithium hydroxide) added with impurities⁷LiOH is subjected to spray centrifugal drying and condensation separation to remove water, and the nano anhydrous lithium hydroxide (A), (B) is prepared⁷LiOH) powder in which the added impurities are distributed homogeneously, the lithium hydroxide⁷LiOH) powder has uniform impurity distribution, and can be used as lithium hydroxide (lithium hydroxide) after system detection and verification⁷LiOH) standard substance.