Device for relieving gas phase channel blockage in fluosilicic acid concentration process

Abstract

A device for relieving gas phase channel blockage in a fluosilicic acid concentration process comprises a kettle body, a hydrofluoric acid pipe and a fluosilicic acid pipe which are communicated with the top of the kettle body, a discharging pipe which is communicated with the bottom of the kettle body, a concentrated solution conveying pump which is installed on the discharging pipe, a condensate collecting tank which is communicated with the top of the kettle body through a gas phase pipe, and a condenser which is installed on the gas phase pipe, a top plate of the condensate collecting tank is communicated with a vacuumizing pipe, the bottom of the condensate collecting tank is communicated with a condensate pipe, and a condensate conveying pump is installed on the condensate pipe. The fluosilicic acid concentration device is used for solving the problem that a gas phase channel is blocked in the fluosilicic acid concentration process.

Description

Technical Field

[0001] The utility model relates to a device for alleviating the blockage of a gas phase channel in the process of concentrating fluorosilicic acid. Background Art

[0002] At present, due to the gradual depletion of fluorite mineral resources, the state has explicitly restricted the further mining of fluorite mines, which has hindered the development of the fluorite method for producing anhydrous hydrogen fluoride. It is urgent to use a new anhydrous hydrogen fluoride production process to replace the fluorite method. For this reason, the process of producing anhydrous hydrogen fluoride by the fluorosilicic acid method has gradually been developed and promoted. Phosphate ore is needed in the production process of wet-process phosphoric acid. The fluorine content in phosphate ore is about 3%. Every ton of phosphorus pentoxide produced will produce 20-60kg of elemental fluorine. In order to make full use of the fluorine resources in phosphate ore, many wet-process phosphoric acid production companies consider using the by-product fluorosilicic acid in the production to produce anhydrous hydrogen fluoride, and then develop downstream fluorine chemical products. However, the mass concentration of fluorosilicic acid produced in the production process of wet-process phosphoric acid is about 12%-18%, which is low for the production of anhydrous hydrogen fluoride. It needs to be concentrated to more than 30% before it can be used. Experimental verification shows that when the concentration of fluorosilicic acid is concentrated to about 23%, fluorosilicic acid will decompose, and the silicon tetrafluoride produced will react with the water vapor produced during the concentration process to form silicon dioxide, which will block the gas phase channel and bring difficulties to the concentration process. At present, many experts and scholars in this research field have published some patents or papers, studied and discussed the reaction conditions of the fluorosilicic acid concentration process, and also proposed some solutions, but in the end they cannot completely solve the problem of gas phase channel blockage during the fluorosilicic acid concentration process. Utility Model Content

[0003] The utility model aims to provide a device for alleviating the blockage of the gas phase channel during the fluosilicic acid concentration process, which is used to solve the problem of the blockage of the gas phase channel during the fluosilicic acid concentration process.

[0004] In order to solve the above problems, the technical solution of the utility model is:

[0005] A device for alleviating the blockage of a gas phase channel in a fluosilicic acid concentration process comprises a kettle body, the top of the kettle body is connected to a hydrofluoric acid pipe and a fluosilicic acid pipe, the bottom of the kettle body is connected to a discharge pipe, a concentrated liquid delivery pump is installed on the discharge pipe, the top of the kettle body is connected to a condensate collecting tank through a gas phase pipe, a condenser is installed on the gas phase pipe, a top plate of the condensate collecting tank is connected to a vacuum pipe, the bottom of the condensate collecting tank is connected to a condensate pipe, and a condensate delivery pump is installed on the condensate pipe.

[0006] Furthermore, a jacket is provided outside the kettle body, the upper end of the jacket is connected with a steam pipe, and the lower end of the jacket is connected with a drain pipe.

[0007] Furthermore, a stirring paddle is provided in the kettle.

[0008] Furthermore, the hydrofluoric acid pipe is connected to the gas phase pipe through a cleaning pipe, and a cleaning control valve and a gas phase control valve are respectively installed on the cleaning pipe and the gas phase pipe.

[0009] Furthermore, one end of the condenser connected to the condensate collecting tank is inclined downward.

[0010] A method for alleviating the blockage of a gas phase channel during the concentration process of fluosilicic acid comprises adding hydrofluoric acid with a concentration of 20-60% together with raw material fluosilicic acid into a kettle body for concentration to form a concentrated mother liquor, wherein the amount of hydrofluoric acid added should be 20-60% of the amount of fluosilicic acid added according to its concentration, so that a sufficient amount of hydrogen fluoride gas is contained in the gas phase during the concentration process, and the situation that the gas phase channel is blocked by hydrolysis of fluosilicic acid to produce silicon dioxide after decomposition into silicon tetrafluoride can be effectively alleviated.

[0011] The utility model has the following beneficial effects: simple operation, economic and environmental protection, industrial application, long system life cycle, and can effectively alleviate the situation where silicon dioxide blocks the gas phase channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The utility model is further described below in conjunction with the accompanying drawings:

[0013] Figure 1 It is a structural schematic diagram of the utility model.

[0014] In the figure: kettle body 1, jacket 2, stirring paddle 3, concentrate delivery pump 4, hydrofluoric acid cleaning control valve 5, kettle top gas phase control valve 6, condenser 7, condensate collecting tank 8, condensate delivery pump 9. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0016] A device for alleviating the blockage of a gas phase channel in a fluosilicic acid concentration process comprises a kettle 1, the top of the kettle 1 is connected to a hydrofluoric acid pipe and a fluosilicic acid pipe, the bottom of the kettle 1 is connected to a discharge pipe, a concentrated liquid delivery pump 4 is installed on the discharge pipe, the top of the kettle 1 is connected to a condensate collecting tank 8 through a gas phase pipe, a condenser is installed on the gas phase pipe, a vacuum pipe is connected to the top plate of the condensate collecting tank 8, a condensate pipe is connected to the bottom of the condensate collecting tank 8, and a condensate delivery pump 9 is installed on the condensate pipe. The vacuum degree of the vacuum pipe is controlled at 80-90KPa, which can effectively reduce the concentration temperature of fluosilicic acid and reduce the decomposition of fluosilicic acid.

[0017] A jacket 2 is provided outside the kettle body 1, the upper end of the jacket 2 is connected to a steam pipe, and the lower end of the jacket 2 is connected to a drain pipe. The jacket 2 is used for heating and concentration, which can effectively avoid the problem of heater blockage during the process of heating and concentrating fluorosilicic acid with a heater, and the concentration temperature is controlled between 50-55°C.

[0018] A stirring paddle 3 is provided in the kettle body 1. The stirring paddle 3 can make the concentrated liquid mixed evenly, because a certain concentration of hydrofluoric acid exists in the kettle body 1, and under stirring, silicon tetrafluoride produced by the decomposition of fluorosilicic acid can be prevented from being hydrolyzed in the concentrated mother liquid to produce silicon dioxide.

[0019] The hydrofluoric acid pipe is connected to the gas phase pipe through a cleaning pipe, and a cleaning control valve and a gas phase control valve are installed on the cleaning pipe and the gas phase pipe respectively. When the gas phase pipeline is blocked, the gas phase pipeline can be cleaned with a certain concentration of hydrofluoric acid by switching the switch between the two valves.

[0020] One end of the condenser connected to the condensate collecting tank 8 is tilted downward.

[0021] The condenser has an inclination angle of 15-30°. The condenser is filled with 5-degree chilled water, which not only condenses the gas phase, but also condenses the hydrogen fluoride gas evaporated from the concentrated mother liquor into liquid and then slowly flows downward in the inclined condenser tube, cleaning the silicon dioxide produced by hydrolysis of fluorosilicic acid after it is concentrated and decomposed into silicon tetrafluoride at low temperature.

[0022] Example 1

[0023] 1) Add 20% hydrofluoric acid and 12% fluorosilicic acid (twice the mass) into the kettle 1, evacuate the top of the condensate collecting tank 8 to a vacuum degree of 85 KPa, and start the chilled water (temperature of about 5°C) of the gas phase condenser 7 on the top of the kettle.

[0024] 2) Steam is introduced into the jacket 2, and the gas phase control valve 6 on the kettle top is opened at the same time to form a vacuum in the kettle body 1. The temperature in the kettle body 1 is controlled at about 55°C to concentrate the fluorosilicic acid. During the concentration process, the hydrofluoric acid cleaning control valve 5 is in a closed state.

[0025] 3) When the concentration of fluorosilicic acid reaches more than 30%, it is transported to the next process for use through the concentrate delivery pump 4. When the liquid level in the condensate collection tank 8 reaches 4 / 5, the condensate is transported to the exhaust gas washing system for reuse through the condensate delivery pump 9. Note that the vacuum cannot be broken during the transportation process.

[0026] 4) If the gas phase channel is blocked during system operation, the hydrofluoric acid cleaning control valve 5 can be opened, and the gas phase channel can be cleaned with hydrofluoric acid by switching the gas phase control valve 6 on the top of the kettle.

[0027] Example 2

[0028] 1) Add 40% hydrofluoric acid and 12% fluorosilicic acid (twice the mass) into the kettle 1, evacuate the top of the condensate collecting tank 8 to a vacuum degree of 85 KPa, and start the chilled water (temperature is about 5°C) of the gas phase condenser 7 on the top of the kettle.

[0029] 2) Steam is introduced into the jacket 2, and the gas phase control valve 6 on the kettle top is opened at the same time to form a vacuum in the kettle body 1. The temperature in the kettle body 1 is controlled at about 55°C to concentrate the fluorosilicic acid. During the concentration process, the hydrofluoric acid cleaning control valve 5 is in a closed state.

[0030] 3) When the concentration of fluorosilicic acid reaches more than 30%, it is transported to the next process for use through the concentrate delivery pump 4. When the liquid level in the condensate collection tank 8 reaches 4 / 5, the condensate is transported to the exhaust gas washing system for reuse through the condensate delivery pump 9. Note that the vacuum cannot be broken during the transportation process.

[0031] 4) If the gas phase channel is blocked during system operation, the hydrofluoric acid cleaning control valve 5 can be opened, and the gas phase channel can be cleaned with hydrofluoric acid by switching the gas phase control valve 6 on the top of the kettle.

[0032] Example 3

[0033] 1) Add 60% hydrofluoric acid and 12% fluorosilicic acid (twice the mass) into the kettle 1, evacuate the top of the condensate collecting tank 8 to a vacuum degree of 85 KPa, and start the chilled water (temperature of about 5°C) of the gas phase condenser 7 on the top of the kettle.

[0034] 2) Steam is introduced into the jacket 2, and the gas phase control valve 6 on the kettle top is opened at the same time to form a vacuum in the kettle body 1. The temperature in the kettle body 1 is controlled at about 55°C to concentrate the fluorosilicic acid. During the concentration process, the hydrofluoric acid cleaning control valve 5 is in a closed state.

[0035] 3) When the concentration of fluorosilicic acid reaches more than 30%, it is transported to the next process for use through the concentrate delivery pump 4. When the liquid level in the condensate collection tank 8 reaches 4 / 5, the condensate is transported to the exhaust gas washing system for reuse through the condensate delivery pump 9. Note that the vacuum cannot be broken during the transportation process.

[0036] 4) If the gas phase channel is blocked during system operation, the hydrofluoric acid cleaning control valve 5 can be opened, and the gas phase channel can be cleaned with hydrofluoric acid by switching the gas phase control valve 6 on the top of the kettle.

[0037] The contents described in the embodiments of this specification are merely an enumeration of the implementation forms of the utility model concept. The protection scope of the utility model should not be deemed to be limited to the specific forms described in the embodiments. The protection scope of the utility model also extends to equivalent technical means that can be thought of by those skilled in the art based on the concept of the utility model.

Claims

1. A device for alleviating the blockage of the gas phase channel during the concentration process of fluosilicic acid, comprising a kettle, the top of which is connected to a hydrofluoric acid pipe and a fluosilicic acid pipe, the bottom of which is connected to a discharge pipe, and a concentrated liquid delivery pump is installed on the discharge pipe, characterized in that: The top of the kettle body is connected to the condensate collecting tank through a gas phase pipe, a condenser is installed on the gas phase pipe, a vacuum pipe is connected to the top plate of the condensate collecting tank, a condensate pipe is connected to the bottom of the condensate collecting tank, and a condensate delivery pump is installed on the condensate pipe.

2. A device for alleviating gas phase channel blockage during fluosilicic acid concentration according to claim 1, characterized in that: A jacket is arranged outside the kettle body, the upper end of the jacket is connected with a steam pipe, and the lower end of the jacket is connected with a drain pipe.

3. A device for alleviating gas phase channel blockage during fluosilicic acid concentration according to claim 1, characterized in that: A stirring paddle is provided in the kettle body.

4. The device for alleviating gas phase channel blockage in the process of fluosilicic acid concentration according to claim 1, characterized in that: The hydrofluoric acid pipe is connected to the gas phase pipe through a cleaning pipe, and a cleaning control valve and a gas phase control valve are respectively installed on the cleaning pipe and the gas phase pipe.

5. A device for alleviating gas phase channel blockage in the process of fluosilicic acid concentration according to any one of claims 1 to 4, characterized in that: One end of the condenser connected to the condensate collecting tank is inclined downward.

6. The device for alleviating gas phase channel blockage in the process of fluosilicic acid concentration according to claim 5, characterized in that: The condenser inclination angle is 15~30°.

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