Device for purifying and concentrating dilute fluosilicic acid solution by extraction method

Abstract

The utility model provides a device for purifying and concentrating a dilute fluosilicic acid solution by an extraction method, which comprises a high-shear extraction reactor, an extraction phase splitter is connected behind the high-shear extraction reactor, the extraction phase splitter is connected with a high-shear reverse extraction reactor, the high-shear reverse extraction reactor is connected with a reverse extraction phase splitter, the reverse extraction phase splitter is connected with a precipitation treatment tank, and the precipitation treatment tank is connected with a precipitation tank. The precipitation treatment pond is connected with the reduced pressure distillation tank; and the reduced pressure distillation tank is connected with the thermal decomposition tank. According to the device, the high-shear reactor is introduced, the extraction and back-extraction time of the dilute fluosilicic acid is remarkably shortened by enhancing the shear force, the extraction and back-extraction process which originally needs 0.5-4 hours is shortened to 5-10 minutes, the purpose of efficient separation is achieved, the production efficiency is remarkably improved, and the economical efficiency and feasibility of the whole process are improved.

Description

Technical Field

[0001] The utility model relates to the field of chemical engineering, and particularly provides a device for extraction purification and concentration for dilute fluosilicic acid solution by-products of phosphorous chemical enterprises. Background Art

[0002] In the wet-process phosphoric acid and phosphate fertilizer industries, fluorine in phosphate rock is usually recovered in the form of fluosilicic acid. Fluosilicic acid is not only a key raw material for producing fluorine salts such as sodium fluoride, hydrogen fluoride, aluminum fluoride and cryolite, but also can be used to prepare silicon-containing compounds such as silicon tetrafluoride and silicon dioxide. In particular, the industrialization of using fluosilicic acid to prepare anhydrous hydrogen fluoride has been realized.

[0003] In the production process of anhydrous hydrogen fluoride, the concentration requirement of fluosilicic acid is extremely strict, and the concentration of fluosilicic acid directly affects the production cost and energy consumption. At present, the concentration of fluosilicic acid usually adopts the concentrated sulfuric acid dehydration method. When the concentration of fluosilicic acid is low, this method needs to consume a large amount of concentrated sulfuric acid and produces a large amount of dilute sulfuric acid, bringing great pressure to the acid balance and water balance of the enterprise. In addition, other common concentration methods also include phosphoric acid concentration method, vacuum falling film evaporation method, absolute dry air dehydration concentration method, and solvent extraction method.

[0004] As a common liquid separation technology, the solvent extraction method has been widely used in many industrial fields, including petrochemical industry, hydrometallurgy, rare earth extraction, nuclear industry, industrial wastewater treatment and pharmacy, etc., due to its high separation efficiency, large processing capacity and low energy consumption. However, in the purification and concentration process of fluosilicic acid, the extraction and back-extraction processes often require a long residence time, usually 0.5 to 4 hours, which limits the process efficiency and production capacity. Summary of the Utility Model

[0005] In order to solve the above problems, the present application proposes a device for extraction purification and concentration of dilute fluosilicic acid solution, which includes a high-shear extraction reactor, the high-shear extraction reactor is connected to an extraction phase separator at the back, the extraction phase separator is connected to a high-shear back-extraction reactor, the high-shear back-extraction reactor is connected to a back-extraction phase separator, the back-extraction phase separator is connected to a precipitation treatment tank, the precipitation treatment tank is connected to a vacuum distillation tank, and the vacuum distillation tank is connected to a thermal decomposition tank.

[0006] The top of the high-shear extraction reactor is connected with a raw material acid pipeline and an extraction liquid pipeline.

[0007] The extraction phase separator is also connected with an inorganic acid pipeline.

[0008] The top of the high-shear back-extraction reactor is connected with a back-extraction agent pipeline.

[0009] The back-extraction phase separator is also connected with a product acid pipeline.

[0010] The top of the precipitation treatment tank is connected to a heavy metal salt pipeline; the bottom of the vacuum distillation tank is connected to an auxiliary agent pipeline; the bottom of the thermal decomposition tank is connected to an extractant pipeline.

[0011] The beneficial effects of the present utility model are as follows:

[0012] This device introduces a high-shear reactor. By enhancing the shear force, the extraction and back-extraction time of dilute fluosilicic acid is significantly shortened. The original extraction and back-extraction process that required 0.5 - 4 hours is shortened to 5 - 10 minutes, achieving the purpose of efficient separation, significantly improving the production efficiency, and enhancing the economy and feasibility of the overall process.

[0013] This device is not only applicable to the purification and concentration of dilute fluosilicic acid, but also can be applied to the efficient extraction and concentration operations of other similar chemical systems. It is suitable for treating dilute fluosilicic acid solutions with a concentration between 2% and 18% produced as by-products by phosphorus chemical enterprises, and is applicable to the production of high-value-added products such as anhydrous hydrogen fluoride. Description of the Drawings

[0014] Figure 1 Schematic connection diagram of the device of the present utility model.

[0015] Explanation of the markings in the figure: raw material acid pipeline 1, extraction liquid pipeline 2, back-extracting agent pipeline 3, heavy metal salt pipeline 4, auxiliary agent pipeline 5, inorganic acid pipeline 6, extractant pipeline 7, high-shear extraction reactor 8, extraction phase separator 9, high-shear back-extraction reactor 10, back-extraction phase separator 11, precipitation treatment tank 12, vacuum distillation tank 13, thermal decomposition tank 14, product acid pipeline 15. Detailed Embodiments

[0016] The following will describe the implementation scheme of the present utility model in detail in combination with embodiments. The following embodiments are only used to illustrate the present utility model and should not be regarded as limiting the scope of the present utility model.

[0017] Embodiment 1

[0018] As Figure 1 shown, a device for purifying and concentrating dilute fluosilicic acid solution by extraction method includes a high-shear extraction reactor 8. The high-shear extraction reactor 8 is connected to an extraction phase separator 9 at the back. The extraction phase separator 9 is connected to a high-shear back-extraction reactor 10. The high-shear back-extraction reactor 10 is connected to a back-extraction phase separator 11. The back-extraction phase separator 11 is connected to a precipitation treatment tank 12. The precipitation treatment tank 12 is connected to a vacuum distillation tank 13. The vacuum distillation tank 13 is connected to a thermal decomposition tank 14.

[0019] The top of the high-shear extraction reactor 8 is connected to a raw material acid pipeline 1 and an extraction liquid pipeline 2.

[0020] The extraction phase separator 9 is also connected to an inorganic acid pipeline 6.

[0021] The top of the high-shear stripping reactor 10 is connected to the stripping agent pipeline 3.

[0022] The stripping phase separator 11 is also connected to the product acid pipeline 15.

[0023] The top of the precipitation treatment tank 12 is connected to the heavy metal salt pipeline 4; the bottom of the vacuum distillation tank 13 is connected to the auxiliary agent pipeline 5; the bottom of the thermal decomposition tank 14 is connected to the extractant pipeline 7.

[0024] Example 2

[0025] Using the device described in Example 1, its working process is described as follows:

[0026] The fluorosilicic acid raw material enters the high-shear extraction reactor 8 through the raw material acid pipeline 1, and the extraction liquid and the auxiliary agent enter through the extraction liquid pipeline 2 for rapid extraction operation. The concentration of the extractant in the extraction liquid is 20-100%, and the extraction time is 5-10 minutes.

[0027] After the extraction is completed, the mixed liquid enters the extraction phase separator 9 to separate the acid phase and the fat phase; the acid phase is inorganic acid and is discharged through the inorganic acid pipeline 6 for recycling; the fat phase is a mixture of extractant, auxiliary agent and fluorosilicic acid, and is introduced into the high-shear stripping reactor 10 to perform rapid stripping with the stripping agent (such as nitric acid, hydrochloric acid, phosphoric acid or sulfuric acid) added through the stripping agent pipeline 3, and the extraction time is 5-10 minutes.

[0028] After the stripping is completed, the mixed liquid enters the stripping phase separator 11 to completely separate fluorosilicic acid from the raffinate (a mixture of extractant, stripping agent and auxiliary agent). The separated fluorosilicic acid flows out through the product acid pipeline 15; the raffinate after stripping enters the precipitation treatment tank 12, and heavy metal salts (such as barium chloride, barium nitrate or lead nitrate) are added to the precipitation treatment tank 12 through the heavy metal salt pipeline 4 to generate barium sulfate or lead sulfate for recycling as by-products.

[0029] Then, the remaining mixed liquid passes through the vacuum distillation tank 13 to recover the auxiliary agent, and the auxiliary agent is recycled through the auxiliary agent pipeline 5. The operating conditions are a vacuum degree of 0.08-0.1 MPa and a temperature of 50-100°C. Finally, the material undergoes thermal decomposition in the thermal decomposition tank 14 to further recover the extractant, and the extractant flows out through the extractant pipeline 7. The operating conditions for thermal decomposition are a heating temperature of 200-400°C, and finally the extractant recovery rate exceeds 80%.

[0030] This device is not only applicable to the purification and concentration of dilute fluorosilicic acid, but also can be applied to the efficient extraction and concentration operations of other similar chemical systems, suitable for treating dilute fluorosilicic acid solutions with a concentration between 2-18% from the by-products of phosphorus chemical enterprises, and applicable to the production of high-value-added products such as anhydrous hydrogen fluoride.

Claims

1. A device for purifying and concentrating dilute fluorosilicic acid solution by extraction method, characterized in that: The invention comprises a high shear extraction reactor (8), the high shear extraction reactor (8) is connected to an extraction phase separator (9), the extraction phase separator (9) is connected to a high shear stripping reactor (10), the high shear stripping reactor (10) is connected to a stripping phase separator (11), the stripping phase separator (11) is connected to a precipitation treatment tank (12), the precipitation treatment tank (12) is connected to a vacuum distillation tank (13), and the vacuum distillation tank (13) is connected to a thermal decomposition tank (14).

2. The device for purifying and concentrating dilute fluorosilicic acid solution by extraction method according to claim 1, characterized in that: The top of the high shear extraction reactor (8) is connected to a raw acid pipeline (1) and an extraction liquid pipeline (2).

3. The device for purifying and concentrating dilute fluorosilicic acid solution by extraction method according to claim 1, characterized in that: The extraction phase separator (9) is also connected to an inorganic acid pipeline (6).

4. The device for purifying and concentrating dilute fluorosilicic acid solution by extraction method according to claim 1, characterized in that: The top of the high shear stripping reactor (10) is connected to a stripping agent pipeline (3).

5. The device for purifying and concentrating dilute fluorosilicic acid solution by extraction method according to claim 1, characterized in that: The stripping phase separator (11) is also connected to a product acid pipeline (15).

6. The device for purifying and concentrating dilute fluorosilicic acid solution by extraction method according to claim 1, characterized in that: The top of the precipitation treatment tank (12) is connected to a heavy metal salt pipeline (4); the bottom of the vacuum distillation tank (13) is connected to an auxiliary agent pipeline (5); and the bottom of the thermal decomposition tank (14) is connected to an extractant pipeline (7).

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