Method for extracting boron in boron-containing organic phase

Abstract

The invention provides a method for extracting boron in a boron-containing organic phase, and relates to the technical field of boron separation. The extraction method provided by the invention comprises the following steps: mixing a boron-containing organic phase with ammonia water, and carrying out reverse extraction to obtain a boron-containing water phase; and crystallizing and separating the boron-containing water phase to obtain ammonium borate. According to the method, ammonium borate can be directly prepared from the boron-containing organic phase, evaporation, concentration and crystallization can be carried out without consuming energy, the obtained ammonium borate solid can be used as a precursor for subsequently preparing boron-containing compounds such as boric acid, borax or boric oxide, the overall energy consumption is low, the operation is simple, considerable economic benefits and social benefits are achieved, and the method is suitable for industrial production. The large-scale popularization and application prospects are realized.

Description

Technical Field

[0001] The invention relates to the technical field of boron separation, and in particular to a method for extracting boron from a boron-containing organic phase. Background Art

[0002] Boron (B) is a key factor in the efficient growth and development of plants; therefore, B-based fertilizers have been used in agricultural applications. Due to the growth of the world's population, the demand for B-based fertilizers for agricultural purposes is increasing. In addition to being used in fertilizers, B is also used in the production of neodymium iron B (NdFeB) permanent magnets. At the same time, B is also one of the vital raw materials in the production of glass, ceramics, etc. Due to the increasing demand for B in various applications, how to prepare borates at a lower cost and in a greener and more environmentally friendly way to improve the economic value of B is very critical.

[0003] At present, adsorption, solvent extraction and bipolar membrane electrodialysis are the most studied methods for recovering B from aqueous media such as seawater, salt lake brine, sewage, industrial wastewater and agricultural wastewater. From these methods, solvent extraction is the most used at the industrial level (producing B from salt lake brine). However, the toxicity of the organic solvents used is still a problem, and the borate solution stripped down also requires a lot of energy to be evaporated, concentrated and crystallized before solid borates can be obtained. There are more than a dozen different types of economic boron-containing minerals in the world, but the cost of extracting commercially available boron compounds such as borax and boric acid is high, and high-purity products are difficult to produce. Therefore, it is urgent to provide a solution to improve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a method for extracting boron from a boron-containing organic phase, which can directly prepare ammonium borate from the boron-containing organic phase without consuming energy for evaporation, concentration and crystallization. The obtained ammonium borate solid can be used as a precursor for the subsequent preparation of boric acid, borax or boron oxide and other boron-containing compounds. The overall energy consumption is low, the operation is simple, there are considerable economic and social benefits, and there is a prospect for large-scale promotion and application.

[0005] The invention provides a method for extracting boron from a boron-containing organic phase, comprising: mixing the boron-containing organic phase with ammonia water and then performing back extraction to obtain a boron-containing aqueous phase; and crystallizing and separating the boron-containing aqueous phase to obtain ammonium borate.

[0006] Optionally, the organic solvent in the boron-containing organic phase includes isooctyl alcohol, isopentanol or 2-ethyl-1,3-hexanediol.

[0007] Optionally, the mass content of boron in the boron-containing organic phase is 0.1 g / L-12 g / L.

[0008] Optionally, 0.1%-20% ammonia water is used to perform single-stage or cascade countercurrent stripping on the boron-containing organic phase to obtain the boron-containing aqueous phase.

[0009] Optionally, the boron-containing organic phase is mixed with an aqueous phase, and then ammonia gas is introduced into the mixture for stripping to obtain a boron-containing aqueous phase.

[0010] Optionally, when the boron-containing aqueous phase is subjected to crystallization separation, the process includes: adding 0.01 g to 0.1 g of ammonium borate seed crystals to the boron-containing aqueous phase.

[0011] Optionally, the boron-containing aqueous phase is subjected to ultrasound-assisted crystallization for 1 min to 30 min.

[0012] Optionally, the crystal size of the ammonium borate is 20 μm-0.5 cm. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a graph showing the solubility of ammonium borate in ammonia water of different concentrations;

[0014] Figure 2 This is a graph showing the solubility of the same mass of boric acid in ammonia water of different concentrations;

[0015] Figure 3 The initial solution, crystallization effect after adding seed crystals and ultrasonic treatment;

[0016] Figure 4 This is a diagram of the crystal size of the initial solution, after adding seed crystals and after ultrasonic treatment;

[0017] Figure 5 The graph of the boron content in the ammonia solution after the ammonia solution was introduced for different time periods;

[0018] Figure 6 The graph of the crystallization rate of ammonium borate in the ammonia solution after being introduced for different time periods;

[0019] Figure 7 The graph of the change of ammonium ion content in the ammonia solution after the ammonia solution was introduced for different time periods;

[0020] Figure 8 This is the cascade countercurrent stripping diagram for 4% ammonia water;

[0021] Fig. 9 This is the cascade countercurrent stripping diagram for 20% ammonia water;

[0022] Fig.10 The organic phase diagram of boron loading was obtained by passing 80% ammonia water in a ratio of 1:1 into the ammonia gas for different time periods;

[0023] Fig.11 This is a graph showing the change in ammonium ion content in ammonia solution when 80% ammonia water is passed in a 1:1 ratio for different periods of time. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with general skills in the field to which the present invention belongs.

[0025] The present invention provides a method for extracting boron from a boron-containing organic phase, comprising: mixing the boron-containing organic phase with ammonia water and then stripping to obtain a boron-containing aqueous phase; and crystallizing and separating the boron-containing aqueous phase to obtain ammonium borate. In this way, ammonium borate can be directly prepared from the boron-containing organic phase without consuming energy for evaporation, concentration and crystallization. The obtained ammonium borate solid can be used as a precursor for the subsequent preparation of boric acid, borax or boron oxide and other boron-containing compounds. The overall energy consumption is low, the operation is simple, there are considerable economic and social benefits, and there is a prospect for large-scale promotion and application.

[0026] In fact, the organic solvent in the boron-containing organic phase includes isooctyl alcohol, isopentanol or 2-ethyl-1,3-hexanediol. Specifically, the organic solvent in the boron-containing organic phase used is necessary to be able to obtain boron from the remaining solution through extraction. In addition, the mass content of boron in the boron-containing organic phase is 0.1g / L-12g / L.

[0027] In some embodiments, 0.1%-20% ammonia water can be used to perform single-stage or cascade countercurrent stripping on the boron-containing organic phase to obtain a boron-containing aqueous phase. Specifically, when countercurrent cascade stripping is used, the number of extraction stages can be 2-20. In addition, during stripping, the ratio of the boron-containing organic phase loaded by stripping is 1-10, so that the boron in the boron-containing organic phase can be fully stripped.

[0028] In some embodiments, the boron-containing organic phase and the aqueous phase may be mixed and then ammonia gas may be introduced into the mixture for stripping to obtain a boron-containing aqueous phase. Thus, ammonia water is generated during the introduction of ammonia gas and the boron in the boron-containing organic phase may be stripped.

[0029] In some embodiments, when the boron-containing aqueous phase is subjected to crystallization separation, 0.01 g to 0.1 g of ammonium borate seed crystals may be added to the boron-containing aqueous phase, and / or the boron-containing aqueous phase may be subjected to ultrasound-assisted crystallization for 1 min to 30 min.

[0030] Specifically, the present invention can make ammonium borate spontaneously crystallize and precipitate by using ammonia water and / or passing ammonia gas to increase the ammonia content in the water phase, and can realize efficient recovery of boron element, wherein the boron crystallization rate can reach 90% by the ammonia gas crystallization method. In fact, adding concentrated ammonia water or passing ammonia gas can make ammonium borate precipitate, and adding crystal seeds, ultrasound, and vigorous stirring during precipitation can accelerate the crystallization process, and ammonium borate crystals of different sizes can be obtained.

[0031] Example 1: Add pure boric acid solution to concentrated ammonia water, stir and let stand for 2 hours, filter and air dry naturally to obtain dry ammonium borate solid, add ammonium borate to 50 mL of ammonia solution of different concentrations until saturated, and then place in a constant temperature oscillator and oscillate at room temperature for 3 hours to achieve a fully dissolved state, centrifuge the suspension and separate the solid and liquid, and record the boron content in the solution after dissolving ammonium borate in ammonia water of different concentrations. Figure 1 As shown. Figure 1 It can be seen that with the increase of ammonia concentration, the overall solubility of ammonium borate decreases continuously.

[0032] Example 2: Add excess boric acid solid to 50 mL of ammonia solution of different concentrations until it is supersaturated, and then place it in a constant temperature oscillator and oscillate at room temperature for 3 hours to achieve a fully dissolved state. After centrifuging the suspension to separate the solid and liquid, record the boron content in the solution after dissolving boric acid in ammonia water of different concentrations. Figure 2 In addition, different amounts of boron were added to 80% ammonia water and 100% ammonia water, and the boron content in the solution and the ammonium borate crystallization rate were shown in Table 1. Figure 2 It can be seen that with the increase of boron addition, ammonium borate crystals begin to precipitate in the solution, and with the increase of ammonium borate crystallization rate, the concentration of boron remaining in the solution will also increase.

[0033] Table 1 Crystallization rate of ammonium borate at different boron addition amounts

[0034]

[0035] Example 3: 7.5 g of boric acid was dissolved in 50 mL of 50% ammonia water to form a supersaturated solution. 0.011 g of ammonium borate seed was added to one conical flask and ultrasonic treatment was performed in another conical flask. After 30 minutes, the state was as follows: Figure 3 As shown, and after standing for 24 hours Figure 4 As shown. Figure 3 and Figure 4 It can be seen that both the addition of seed crystals and ultrasonic treatment can promote the precipitation of ammonium borate in solid form, and after standing, ammonium borate crystals with a size of 20 μm-200 μm can be obtained. In addition, the ammonium borate crystallization rates calculated under the three methods are shown in Table 2 below.

[0036] Table 2 Ammonium borate crystallization rate

[0037] Boron content (g / L) Crystallization rate / % Add 0.011g seed 5.8422 75.85 Ultrasound 6.1927 74.40 Natural crystal 6.9461 71.29

[0038] Example 4: Take 40 mL of ammonia solution containing 10 g / L boron, pass ammonia gas into it and start timing. After the solution is cooled to room temperature after passing ammonia gas for more than 20 minutes, ammonium borate solid can be precipitated. The boron content in the solution after passing ammonia gas for different times is as follows: Figure 5 As shown, the crystallization rate of ammonium borate is Figure 6 As shown, the ammonium ion content in the solution is Figure 7 As shown, as the time of passing ammonia gas increases, the boron content in the solution continues to decrease, and the ammonium content in the solution first increases and then decreases. When ammonia gas is passed for 30 minutes, the boron content in the solution does not decrease significantly, and the ammonium borate crystallization rate reaches more than 90%.

[0039] Example 5: The organic phase was contacted with the boric acid solution, placed in a constant temperature water bath oscillator for 15 minutes to fully mix, and then placed in a separating funnel for phase separation to obtain a boron-containing organic phase. The boron-containing organic phase was mixed with ammonia water at a ratio of 1:1, placed in a constant temperature water bath oscillator for 15 minutes to fully mix, and then placed in a separating funnel for phase separation. The stripping rate is shown in Table 3, wherein solids were precipitated during stripping with 90% and 100% ammonia water. When 90% ammonia water was used, the precipitation rate of ammonium borate in the solution was 66.43%, and when 100% ammonia water was used, the precipitation rate of ammonium borate was 58.58%.

[0040] Table 3 Effect of different concentrations of ammonia water on the back extraction of boron-containing organic phase

[0041] Ammonia percentage / % 50 60 70 90 100 Stripping rate / % 50.53 45.31 43.95 49.81 53.51 Whether precipitation no no no yes yes

[0042] Example 6: 4% and 20% ammonia water were contacted with the boron-loaded organic phase in four-stage countercurrent with a ratio of O / A = 1:1 and 2:1 respectively to obtain a clear and transparent boron-containing ammonia solution. The boron content in each stage of the solution was as follows: Figure 8 , 9 As shown. In the above solutions, boron-containing solution: concentrated ammonia water were added in different proportions and stirred. The boron content of the supernatant is shown in Table 4. The boron content in the 4% ammonia fourth-stage stripping solution is much lower than that in the 20% ammonia fourth-stage stripping solution. The subsequent addition of concentrated ammonia ammonium borate to the 4% ammonia fourth-stage stripping solution is not good. Compared with the 20% ammonia fourth-stage stripping solution with O / A = 1:1 and 2:1, the crystallization rates of the boron-containing solution: concentrated ammonia water = 2:1 were 34.01% and 21.02%, respectively; the crystallization rates of the boron-containing solution: concentrated ammonia water = 1:1 were 23.85% and 22.52%, respectively.

[0043] Table 4 Four-stage cascade countercurrent stripping solution supplemented with concentrated ammonia crystallization

[0044]

[0045] Example 7: Take 20 mL of the organic phase loaded with 11 g / L boron and add 20 mL of 80% ammonia water. Then, introduce ammonia gas into the organic phase and start timing. After the ammonia gas is introduced for more than 20 minutes, the solution begins to precipitate ammonium borate solid. The boron content in the solution after the ammonia gas is introduced for different times is as follows: Fig.10 As shown, the ammonium ion content in the solution is Fig.11 As shown, the final stripping rate was 62.25% and the ammonium borate crystallization rate was 54.05%.

[0046] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as described in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.

Claims

1. A method for extracting boron from a boron-containing organic phase, characterized in that: include: The boron-containing organic phase is mixed with aqueous ammonia and then stripped to obtain a boron-containing aqueous phase; The boron-containing aqueous phase is crystallized and separated to obtain ammonium borate.

2. The extraction method according to claim 1, characterized in that The organic solvent in the boron-containing organic phase includes isooctyl alcohol, isopentanol or 2-ethyl-1,3-hexanediol; and / or the mass content of boron in the boron-containing organic phase is 0.1 g / L-12 g / L.

3. The extraction method according to claim 1, characterized in that The boron-containing organic phase is subjected to single-stage or cascade countercurrent stripping with 0.1%-20% ammonia water to obtain a boron-containing aqueous phase.

4. The extraction method according to claim 1, characterized in that The boron-containing organic phase is mixed with the aqueous phase, and then ammonia gas is introduced into the mixture for reverse extraction to obtain the boron-containing aqueous phase.

5. The extraction method according to claim 1, characterized in that When the boron-containing aqueous phase is subjected to crystallization separation, the method includes: adding 0.01 g to 0.1 g of ammonium borate seed crystals to the boron-containing aqueous phase; and / or performing ultrasonic-assisted crystallization on the boron-containing aqueous phase for 1 min to 30 min.

6. The extraction method according to any one of claims 1 to 5, characterized in that The crystal size of the ammonium borate is 20 μm-0.5 cm.

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