A method for preparing rubidium hydroxide monohydrate
Patent Information
- Application Number
- CN202611491154.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-09-23
- Publication Date
- 2026-11-03
AI Technical Summary
Existing methods for preparing rubidium hydroxide produce products with small particle size, which are difficult to store and unstable. They are also prone to hydrolysis at high temperatures, failing to meet industrial requirements.
Rubidium carbonate, calcium oxide and water were mixed and converted, and after concentration, additives such as sodium dodecyl sulfonate, glycine and citric acid were added. The mixture was then subjected to negative pressure distillation and gradient cooling. After solid-liquid separation, vacuum drying was performed to prepare large-particle rubidium hydroxide monohydrate crystals.
Rubidium hydroxide monohydrate with granular and regularly arranged crystals was prepared. It is not easily hydrolyzed at high temperatures and is not easily affected by moisture under normal conditions. The product has high purity and impurities are less than 0.01%.
Smart Images
Figure CN123026239A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of chemical production technology, and in particular to a method for preparing rubidium hydroxide monohydrate. Background Technology
[0002] Rubidium is a chemically reactive alkali metal element, with an abundance of 5.1 × 10⁻⁶ in the Earth's crust. -5 Up to 3.1×10 -4 Rubidium ranks 16th in elemental abundance. As a scarce alkali metal resource, rubidium is widely used in industrial catalysis, specialty glass, electronics, energy, and pharmaceutical industries, and also has a certain market in aerospace and information technology. Currently, rubidium resources are mainly found in salt lake brines, lepidolite, and cesium garnet, generally coexisting with elements such as lithium and potassium. With the continuous development of salt lake brines and lepidolite resources, rubidium extraction technologies have also been developed in the process of lithium extraction. With the continuous development of science and technology, the demand for rubidium salts is also constantly increasing. As high technologies are constantly being updated, the demand for rubidium hydroxide is also continuously increasing.
[0003] The current method for preparing rubidium hydroxide involves causticizing barium hydroxide to obtain a rubidium hydroxide solution, concentrating the solution, and then cooling it to obtain the rubidium hydroxide product. However, this method results in rubidium hydroxide hydrate products with drawbacks such as small particle size, difficulty in storage, unstable crystals, and hydration upon heating. Therefore, providing a method for preparing large-particle rubidium hydroxide monohydrate to produce stable rubidium hydroxide monohydrate crystals is of great significance. Summary of the Invention
[0004] The purpose of this invention is to provide a method for preparing rubidium hydroxide monohydrate. The prepared rubidium hydroxide is in granular form and has the advantages of regular and stable crystal shape arrangement, non-decomposition at high temperature and non-hygroscopicity under normal conditions.
[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing rubidium hydroxide monohydrate, comprising the following steps: Rubidium carbonate, calcium oxide and water are mixed to undergo a transformation, yielding a transformation liquid and a transformation residue. The conversion solution was concentrated and filtered to obtain a concentrated solution and calcium hydroxide residue. The concentrated liquid and additives are mixed and distilled under negative pressure. The resulting solution is cooled and kept at a constant temperature, and then subjected to gradient cooling and solid-liquid separation to obtain rubidium hydroxide monohydrate wet material. The wet rubidium hydroxide hydrate was vacuum dried to obtain rubidium hydroxide monohydrate. The additives include one or more of sodium dodecyl sulfonate, glycine, and citric acid.
[0006] Preferably, the molar ratio of rubidium carbonate to calcium oxide is 1:1 to 1.5.
[0007] Preferably, the transformation temperature is 20~100℃ and the time is 30~240 min; the mass concentration of rubidium ions in the transformation solution is 50~200 g / L.
[0008] Preferably, the density of the concentrate is 1.3~1.5 g / cm³. 3 .
[0009] Preferably, when the additive is sodium dodecyl sulfonate, glycine and citric acid, the mass ratio of sodium dodecyl sulfonate, glycine and citric acid is 1:1:2~5.
[0010] Preferably, the mass of the additive is 0.01 to 0.1% of the mass of rubidium ions in the concentrate.
[0011] Preferably, the pressure of the negative pressure distillation is -0.1 MPa to -0.02 MPa, the starting temperature of the negative pressure distillation is 40 to 60°C, and the ending temperature is 100 to 200°C.
[0012] Preferably, the heat preservation temperature is 50~100℃ and the time is 1~3 h; the gradient cooling rate is 1~10℃ / h and the final temperature of the gradient cooling is 40~60℃.
[0013] Preferably, the vacuum drying temperature is 130~150℃ and the time is 4~8 h.
[0014] Preferably, the particle size of the rubidium hydroxide monohydrate is D50 = 200~300 μm.
[0015] The beneficial effects of this invention are: This invention provides a method for preparing large-particle rubidium hydroxide monohydrate. The method involves mixing rubidium carbonate, calcium oxide, and water to undergo a transformation process, yielding a transformation liquid and a transformation residue. The transformation liquid is concentrated to obtain a concentrated liquid and calcium hydroxide residue. The concentrated liquid is mixed with additives and subjected to negative pressure distillation. The resulting solution is cooled and held at a constant temperature, then subjected to gradient cooling for solid-liquid separation to obtain a wet rubidium hydroxide monohydrate. The wet rubidium hydroxide monohydrate is then vacuum dried to obtain rubidium hydroxide monohydrate. This invention adds specific additives to the concentrated liquid to induce oriented crystal arrangement during rubidium hydroxide crystallization upon cooling, resulting in large-particle rubidium hydroxide monohydrate crystals. The obtained rubidium hydroxide monohydrate is granular, with a regular and stable crystal shape arrangement. It does not decompose at high temperatures and is not easily hygroscopic under normal conditions. The product has a water-to-rubidium ratio of 1:1 and impurities of less than 0.01%. Attached Figure Description
[0016] Figure 1This is a photograph of the rubidium hydroxide monohydrate product from Example 1. Figure 2 This is a photograph of the rubidium hydroxide monohydrate product from Comparative Example 1. Figure 3 This is a photograph of the rubidium hydroxide monohydrate product from Comparative Example 2. Detailed Implementation
[0017] This invention provides a method for preparing rubidium hydroxide monohydrate, comprising the following steps: Rubidium carbonate, calcium oxide and water are mixed to undergo a transformation, yielding a transformation liquid and a transformation residue. The conversion solution was concentrated and filtered to obtain a concentrated solution and calcium hydroxide residue. The concentrated liquid and additives are mixed and distilled under negative pressure. The resulting solution is cooled and kept at a constant temperature, and then subjected to gradient cooling and solid-liquid separation to obtain rubidium hydroxide monohydrate wet material. The wet rubidium hydroxide hydrate was vacuum dried to obtain rubidium hydroxide monohydrate. The additives include one or more of sodium dodecyl sulfonate, glycine, and citric acid.
[0018] In this invention, unless otherwise specified, all raw materials required for preparation are commercially available products well known to those skilled in the art.
[0019] In this invention, the molar ratio of rubidium carbonate to calcium oxide is preferably 1:1 to 5, more preferably 1:1.1 to 1.4, and even more preferably 1:1.2 to 1.3.
[0020] In this invention, the transformation temperature is preferably 20℃~100℃, more preferably 30℃~90℃, and even more preferably 40℃~80℃, and the transformation time is preferably 30~240 min, more preferably 60~210 min, and even more preferably 90~180 min.
[0021] In this invention, the rubidium ion mass concentration in the transformation solution is 50~200 g / L, more preferably 70~180 g / L, and even more preferably 90~150 g / L.
[0022] In this invention, the density of the concentrated solution is preferably 1.3~1.5 g / cm³. 3 More preferably 1.35 g / cm 3 .
[0023] In this invention, the additive preferably includes one or more of sodium dodecyl sulfonate, glycine, and citric acid; the mass of the additive is preferably 0.01-0.1% of the mass of rubidium ions in the concentrate, more preferably 0.02%-0.08%, and even more preferably 0.04%-0.06%; when the additive is sodium dodecyl sulfonate, glycine, and citric acid, the mass ratio of sodium dodecyl sulfonate, glycine, and citric acid is preferably 1:1:2-5, and more preferably 1:1:2.
[0024] In this invention, the pressure of the negative pressure distillation is preferably -0.1 MPa to -0.02 MPa, more preferably -0.09 MPa to -0.03 MPa, and even more preferably -0.08 MPa to -0.04 MPa; the starting temperature of the negative pressure distillation is preferably 40 to 60°C, more preferably 42 to 58°C, and even more preferably 45 to 55°C; the ending temperature of the negative pressure distillation is preferably 100 to 200°C, more preferably 110°C to 190°C, and even more preferably 120°C to 180°C.
[0025] In this invention, the temperature of the heat preservation is preferably 50~100℃, more preferably 90℃, and the time is preferably 1~3 h, more preferably 2 h; the heat preservation is for the purpose of generating seed crystals.
[0026] In this invention, the gradient cooling rate is preferably 1~10℃ / h, more preferably 5℃ / h; the final temperature of the gradient cooling is 40~60℃, more preferably 50℃.
[0027] In this invention, the vacuum drying temperature is preferably 130~150℃, more preferably 130℃, and the time is preferably 4~8 h, more preferably 8 h.
[0028] In this invention, the particle size of the rubidium hydroxide monohydrate is preferably D50 = 200~300 μm, and more preferably 223 μm.
[0029] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.
[0030] Example 1
[0031] 1 kg of rubidium carbonate with a purity of 99% was added to 7 L of pure water, and 270 g of calcium oxide with a purity of 98% was added. The mixture was heated to 50°C and stirred at 50°C for 1 h. The solid and liquid were then separated to obtain the transformation liquid and the transformation residue. The mass concentration of rubidium ions in the transformation liquid was 127 g / L. The conversion solution was heated to 70°C and concentrated, then filtered while hot to obtain a concentrated solution and calcium hydroxide residue. The density of the concentrated solution was 1.35 g / cm³. 3 ; Add 0.6 g sodium dodecyl sulfonate, 0.6 g g glycine and 1.2 g citric acid mixed additive to the concentrate. The mass of the mixed additive is 0.04% of the mass of rubidium ions in the concentrate. Place it in a negative pressure distillation vessel and carry out negative pressure distillation at -0.05 MPa. The starting temperature is 50℃. Distill to an internal temperature of 135℃. Cool to 90℃ and hold for 2 h. The resulting solution is subjected to gradient cooling at a rate of 5℃ / h. After cooling to 50℃, solid-liquid separation is performed to obtain 421.5 g rubidium hydroxide hydrate wet material. The wet rubidium hydroxide hydrate was added to a vacuum drying oven and dried at 130°C for 8 hours to obtain 408.3 g of rubidium hydroxide monohydrate.
[0032] Comparative Example 1
[0033] The only difference from Example 1 is: Without adding any additives, the concentrate was concentrated at atmospheric pressure to an internal temperature of 160°C, cooled to 90°C and held for 2 hours. The resulting solution was then subjected to a gradient cooling at a rate of 5°C / h. After cooling to 50°C, solid-liquid separation was performed to obtain 413.1 g of rubidium hydroxide wet material. When wet rubidium hydroxide hydrate is added to a vacuum drying oven and dried at 130°C, it turns into water and the product cannot be obtained.
[0034] Comparative Example 2
[0035] The only difference from Example 1 is: No additives are added; With other parameters unchanged, 414.2 g of rubidium hydroxide monohydrate product was obtained.
[0036] Characterization and performance testing
[0037] 1. Figures 1-3 The images shown are of the actual products from Example 1 and Comparative Examples 1 and 2, respectively. Compare Figures 1-3 It can be seen that after the additive was added in Example 1, the product particles were uniform and large in size, and were not easily affected by moisture in the air. They could exist stably in the air and were not easily turned into water. The product of Comparative Example 1 was unstable because of the inclusion of some water of crystallization. When drying, the water of crystallization was released, dissolving the product and causing it to turn into water. Comparative Example 2 did not add any additives. The product particles were small and the crystal particles were fine. It was extremely easy to be affected by moisture in the air and was difficult to store.
[0038] 2. The elemental content and particle size of the products in Example 1 and Comparative Examples 1-2 were tested, and the results are shown in Table 1. Table 1. Rubidium hydroxide monohydrate product data
[0039] As can be seen from Table 1, the molar ratio of rubidium hydroxide and water content is 1:1:1, which suggests that the preparation method of the present invention can prepare rubidium hydroxide monohydrate RbOH·H2O. Furthermore, comparing the D50 particle size of the products of Example 1 and Comparative Examples 1-2, it can be seen that the particle size increases significantly after the addition of additives and the impurities of the products meet the requirements of 4N rubidium salt.
[0040] As can be seen from the above embodiments, the present invention provides a method for preparing rubidium hydroxide monohydrate. Rubidium carbonate, calcium oxide, and water are mixed to undergo a transformation process, yielding a transformation liquid and a transformation slag. The transformation liquid is concentrated to obtain a concentrated liquid and calcium hydroxide slag. The concentrated liquid is mixed with additives and subjected to negative pressure distillation. The resulting solution is then subjected to gradient cooling and solid-liquid separation to obtain a wet rubidium hydroxide monohydrate hydrate. The wet rubidium hydroxide hydrate hydrate is then subjected to gradient cooling and solid-liquid separation to obtain rubidium hydroxide monohydrate. The present invention, by adding specific additives to the concentrated liquid, causes the crystals of rubidium hydroxide to align directionally during cooling and crystallization, resulting in large-particle rubidium hydroxide monohydrate crystals. The obtained rubidium hydroxide monohydrate is granular, with a regular and stable crystal shape arrangement, does not decompose at high temperatures, and is not easily hygroscopic under normal conditions. The product impurities are less than 0.01%.
[0041] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for preparing rubidium hydroxide monohydrate, characterized in that, Includes the following steps: Rubidium carbonate, calcium oxide and water are mixed to undergo a transformation, yielding a transformation liquid and a transformation residue. The conversion solution was concentrated and filtered to obtain a concentrated solution and calcium hydroxide residue. The concentrated liquid and additives are mixed and subjected to negative pressure distillation. The resulting solution is cooled and kept at a constant temperature, and then subjected to gradient cooling and solid-liquid separation to obtain rubidium hydroxide monohydrate wet material. The wet rubidium hydroxide hydrate was vacuum dried to obtain rubidium hydroxide monohydrate. The additives include one or more of sodium dodecyl sulfonate, glycine, and citric acid.
2. The preparation method according to claim 1, characterized in that, The molar ratio of rubidium carbonate to calcium oxide is 1:1 to 1.
5.
3. The preparation method according to claim 2, characterized in that, The transformation temperature is 20~100℃, and the time is 30~240 min; the mass concentration of rubidium ions in the transformation solution is 50~200 g / L.
4. The preparation method according to claim 1 or 3, characterized in that, The concentration temperature is 20~100℃, and the density of the concentrated solution is 1.3~1.5 g / cm³. 3 .
5. The preparation method according to claim 1, characterized in that, When the additive is sodium dodecyl sulfonate, glycine and citric acid, the mass ratio of sodium dodecyl sulfonate, glycine and citric acid is 1:1:2~5.
6. The preparation method according to claim 1 or 5, characterized in that, The mass of the additive is 0.01 to 0.1% of the mass of rubidium ions in the concentrate.
7. The preparation method according to claim 1, characterized in that, The pressure of the negative pressure distillation is -0.1 MPa to -0.02 MPa, the starting temperature of the negative pressure distillation is 40 to 60°C, and the ending temperature is 100 to 200°C.
8. The preparation method according to claim 1, characterized in that, The heat preservation temperature is 50~100℃, and the time is 1~3 h; the gradient cooling rate is 1~10℃ / h, and the final temperature of the gradient cooling is 40~60℃.
9. The preparation method according to claim 1, characterized in that, The vacuum drying temperature is 130~150℃, and the time is 4~8 h.
10. The preparation method according to claim 1, characterized in that, The particle size of the rubidium hydroxide monohydrate is D50 = 200~300 μm.