阅读说明：本技术 一种无水硼酸锂助熔剂的制备方法 (Preparation method of anhydrous lithium borate fluxing agent ) 是由 秦长勇 于 2019-10-17 设计创作，主要内容包括：本发明一种无水硼酸锂助熔剂的制备方法,包括下列制备步骤：(1)化学机械球磨；(2)喷雾干燥造粒；(3)高温热处理；(4)高温快速熔炼玻化：将所述步骤(3)所得的无水硼酸锂粉体在自制高温熔炼炉中快速熔炼玻璃化,冷却得到高密度的无水硼酸锂玻璃砂。本发明的优点：消除了产品中的碳酸锂残存率,成本低,工艺简单,适合大规模工业使用。提高了制成浆料的固含量,不需要浓缩,减少后续水蒸发量,大幅度降低生产能耗优于传统的干燥再粉碎工艺,不仅减低了杂质引入量,也减低了能耗。使产品粉体颗粒快速转化成玻璃微珠,提高产品的致密度。(The invention relates to a preparation method of an anhydrous lithium borate fluxing agent, which comprises the following preparation steps: (1) chemical mechanical ball milling; (2) spray drying and granulating; (3) high-temperature heat treatment; (4) high-temperature rapid melting and vitrification: and (4) rapidly melting and vitrifying the anhydrous lithium borate powder obtained in the step (3) in a self-made high-temperature melting furnace, and cooling to obtain the high-density anhydrous lithium borate glass sand. The invention has the advantages that: the method eliminates the residual rate of lithium carbonate in the product, has low cost and simple process, and is suitable for large-scale industrial use. The solid content of the prepared slurry is improved, concentration is not needed, the subsequent water evaporation capacity is reduced, the production energy consumption is greatly reduced and is superior to that of the traditional drying and re-crushing process, the impurity introduction amount is reduced, and the energy consumption is also reduced. The powder particles of the product are quickly converted into the glass beads, and the density of the product is improved.)

1. The preparation method of the anhydrous lithium borate fluxing agent is characterized by comprising the following preparation steps:

(1) Chemical mechanical ball milling: firstly, adding boric acid and lithium carbonate into a stirring ball-milling tank (with a jacket structure) according to a certain weight ratio, adding deionized water and grinding beads with the diameter of 3 mm, heating to the temperature of 60-80 ℃ in the tank by using a heating circulator, continuously stirring for 1-2 hours, and filtering to remove the grinding beads to obtain water-containing lithium borate slurry;

(2) spray drying and granulating: converting the slurry with the solid content of 40% obtained in the step (1) into powder particles by using a spray dryer, and controlling the temperature of hot drying air to be 250-300 ℃;

(3) High-temperature heat treatment: placing the powder prepared in the step (2) in a high-temperature electric furnace, and carrying out heat treatment for 2-4 hours at 600-800 ℃;

(4) High-temperature rapid melting and vitrification: and (4) rapidly melting and vitrifying the anhydrous lithium borate powder obtained in the step (3) in a self-made high-temperature melting furnace, and cooling to obtain the high-density anhydrous lithium borate glass sand.

2. The method for preparing the anhydrous lithium borate flux according to claim 1, wherein the purity of the boric acid and lithium carbonate in step (1) is 99.9%.

3. The method for preparing an anhydrous lithium borate flux according to claim 1, wherein the solid content of the lithium borate slurry in the step (1) is 40%.

4. The method for preparing an anhydrous lithium borate flux according to claim 1, wherein the particle size of the powder particles in step (2) is controlled to be 400-600 μm.

5. the method for preparing an anhydrous lithium borate flux according to claim 1, wherein the hydrous lithium borate in the step (3) is subjected to a high temperature dehydration and sintering reaction at a temperature of 600 to 750 ℃ to obtain lithium borate crystal particles.

6. The method for preparing the anhydrous lithium borate flux according to claim 1, wherein the rapid melting glass transition temperature in the step (4) is 1400-1600 ℃.

7. the method for preparing the anhydrous lithium borate flux according to claim 1, wherein the diameter of the anhydrous lithium borate glass sand in the step (4) is 200-500 μm.

Technical Field

The invention relates to the field of preparation of an anhydrous lithium borate fluxing agent special for analysis and test, in particular to a preparation method of the anhydrous lithium borate fluxing agent.

Background

with the development of modern analytical testing techniques, X-ray fluorescence (XRF) and plasma mass spectrometry (ICP-MS) have found widespread use in construction, metallurgy, and environmental analysis. Of the two test methods, melt sampling with anhydrous borate was the most critical step. The most used at present are anhydrous lithium tetraborate which is acidic and can be melted with alkaline samples and lithium metaborate which is weakly alkaline and can be melted with acidic samples. Since the sample generally contains both a meta-acid and a meta-basic oxide, the mixed flux is used in a relatively large amount, and the ratio of lithium tetraborate to lithium metaborate in a commercially available flux is 67:33, 50:50 or 33:67 (wt% W%). A high quality anhydrous lithium borate flux contains the following requirements: (1) high purity, up to > 99.5%; (2) the components are uniform, and the granularity is 100-600 mu m; (3) high bulk density, >0.9 g/mL.

The preparation method of the anhydrous lithium borate for the current analytical test mainly comprises the following steps: high temperature solid phase method, liquid phase synthesis method and high temperature melting method. The high-temperature solid phase method mixes lithium carbonate and boric acid according to a metering ratio and then carries out high-temperature calcination reaction, and has the main defects that a large amount of carbon dioxide gas is generated to cause a porous structure of a product, the bulk density is low, and the uniformity of the product is lower than that of other methods. The liquid phase method is to dissolve boric acid in boiling water and react with lithium hydroxide, and because the reaction solubility is low, the obtained slurry needs to be concentrated, dried and dehydrated, and the energy waste is serious. Another critical disadvantage is that boric acid has high solubility in water and is easily lost during filtration separation, resulting in misalignment of chemical components of the product, and although boric acid is generally added in an excessive amount, an accurate chemical composition cannot be guaranteed. Meanwhile, the price of lithium hydroxide is greatly higher than that of lithium carbonate, and the production cost is higher. The high temperature melting method is similar to the high temperature solid phase method, but the temperature is high enough to make the product completely molten, then quenching is carried out to obtain the glass block-packed product, and the final product is obtained by crushing. The method can improve the product density, but impurities are easy to be brought in the crushing process, and a melting vessel generally adopts a platinum crucible, so that the production cost is greatly increased.

Disclosure of Invention

In order to solve the defects of the prior art, the invention provides a preparation method of the anhydrous lithium borate fluxing agent, which can prepare the anhydrous lithium borate fluxing agent with high quality by using chemical mechanical ball milling and spray drying granulation processes.

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

A preparation method of an anhydrous lithium borate fluxing agent comprises the following preparation steps:

(1) Chemical mechanical ball milling: firstly, adding boric acid and lithium carbonate into a stirring ball-milling tank (with a jacket structure) according to a certain weight ratio, adding deionized water and grinding beads with the diameter of 3 mm, heating to the temperature of 60-80 ℃ in the tank by using a heating circulator, continuously stirring for 1-2 hours, and filtering to remove the grinding beads to obtain water-containing lithium borate slurry;

(2) Spray drying and granulating: converting the slurry with the solid content of 40% obtained in the step (1) into powder particles by using a spray dryer, and controlling the temperature of hot drying air to be 250-300 ℃;

(3) high-temperature heat treatment: placing the powder prepared in the step (2) in a high-temperature electric furnace, and carrying out heat treatment for 2-4 hours at 600-800 ℃;

(4) High-temperature rapid melting and vitrification: and (4) rapidly melting and vitrifying the anhydrous lithium borate powder obtained in the step (3) in a self-made high-temperature melting furnace, and cooling to obtain the high-density anhydrous lithium borate glass sand.

In a further description of the present invention, in the step (1), the purity of the boric acid and lithium carbonate content is 99.9%.

In a further description of the present invention, the lithium borate slurry in step (1) has a solids content of 40%.

as a further description of the present invention, the particle size of the powder particles in the step (2) is controlled to be 400 to 600. mu.m.

in a further description of the present invention, the hydrous lithium borate in the step (3) is subjected to a high-temperature dehydration and sintering reaction at a temperature of 600 to 750 ℃ to obtain lithium borate crystal particles.

in a further description of the invention, the rapid melting glass transition temperature in the step (4) is 1400-1600 ℃.

In a further description of the present invention, the diameter of the anhydrous lithium borate glass sand in the step (4) is 200 to 500 μm.

Compared with the prior art, the invention has the advantages that:

1. the invention takes boric acid and lithium carbonate as raw materials, greatly improves the acidolysis reaction efficiency of the lithium carbonate through ball milling chemical mechanical reaction, eliminates the residual rate of the lithium carbonate in the product, has low cost and simple process, and is suitable for large-scale industrial use.

2. The invention adopts a ball-milling chemical mechanical reaction method, breaks through the limitation that the common chemical reaction is limited by the low solubility of boric acid and lithium carbonate, improves the solid content of the prepared slurry, does not need concentration, reduces the subsequent water evaporation capacity and greatly reduces the production energy consumption.

3. The invention adopts a spray drying granulation method, not only the drying is fast, but also the granularity of the obtained powder particles is uniform and controllable, which is superior to the traditional drying and re-crushing process, and not only the impurity introduction amount is reduced, but also the energy consumption is reduced.

4. The invention adopts a special high-temperature melting vitrification device method, so that the powder particles of the product are quickly converted into the glass microspheres, and the density of the product is improved.

drawings

FIG. 1 is a process schematic flow diagram.

FIG. 2 is a schematic view of a high-temperature rapid melting and vitrifying apparatus.

FIG. 3 is an XRD spectrum of example 1.

FIG. 4 is an XRD spectrum of example 3.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.