Production system of reagent-grade aluminum chloride crystals

Abstract

The utility model relates to the technical field of chemical production, in particular to a reagent-grade aluminum chloride crystal production system which comprises a primary crystallization kettle, a first solid-liquid separation device, a dissolving kettle, a secondary crystallization kettle, a second solid-liquid separation device and a crusher which are communicated in sequence, air inlet pipes are arranged below the primary crystallization kettle and the secondary crystallization kettle, air outlet pipes are arranged at the tops of the primary crystallization kettle and the secondary crystallization kettle, and a water inlet pipe is further arranged on the dissolving kettle. According to the utility model, hydrogen chloride gas is introduced into an aluminum chloride solution, aluminum chloride crystals are crystallized at normal temperature, and the aluminum chloride crystals obtained by primary crystallization are re-dissolved and re-crystallized, so that the purity of the aluminum chloride crystals is further improved, and the production of reagent-grade aluminum chloride crystals can be realized.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical production, and in particular to a production system for reagent-grade aluminum chloride crystals. Background Art

[0002] The current method for preparing aluminum chloride crystals is generally to use hydrochloric acid to dissolve bauxite, fly ash, etc. to obtain an aluminum chloride solution. After the aluminum chloride solution is purified and removed from the impurities, it is evaporated and concentrated, cooled and crystallized, and solid-liquid separation is performed to obtain crystalline aluminum chloride. However, this method has the following problems: 1. The impurity removal technology of the aluminum chloride solution is resin adsorption to remove iron, and other impurity ions (sodium, potassium, magnesium, calcium, etc.) are not removed. The purity of the obtained crystalline aluminum chloride is not high. To meet the purity requirements, subsequent purification treatment is required; 2. The entire crystallization process is complex and requires an evaporation crystallization step. This step is not only energy-intensive but also has high equipment requirements.

[0003] Patent CN107285351A discloses a method for extracting high-purity aluminum chloride by leaching fly ash with hydrochloric acid. Hydrogen chloride gas is introduced into the fly ash and hydrochloric acid leachate, causing the aluminum chloride in the leachate to crystallize into aluminum chloride hexahydrate crystals and precipitate. This crystallization process can be carried out at room temperature, reducing energy consumption and overcoming the high energy consumption of the prior art evaporation and concentration crystallization process for aluminum chloride. Furthermore, by directly introducing hydrogen chloride gas into the leachate and crystallizing aluminum chloride crystals at room temperature, impurity ions (sodium, potassium, magnesium, calcium, etc.) can be retained in the residual liquid, overcoming the drawbacks of the prior art, such as complex impurity removal processes such as resin adsorption for iron removal, and the inability to remove other impurity ions (sodium, potassium, magnesium, calcium, etc.).

[0004] Although the prior art discloses that the use of hydrogen chloride gas to prepare crystalline aluminum chloride can obtain relatively high-purity aluminum chloride crystals at room temperature, the relevant research focuses on the method step of using hydrogen chloride for crystallization. There is no relevant technology that discloses how to introduce hydrogen chloride gas into the process system, or how to design the process system so that hydrogen chloride gas can be used to obtain ultra-high-purity crystalline aluminum chloride that meets reagent-grade standards. Utility Model Content

[0005] The purpose of the utility model is to provide a system for generating ultra-high purity crystalline aluminum chloride with reagent grade standard.

[0006] To solve the above technical problems, this application provides the following technical solutions:

[0007] A reagent-grade aluminum chloride crystal production system comprises a primary crystallization kettle, a first solid-liquid separation device, a dissolution kettle, a secondary crystallization kettle, a second solid-liquid separation device and a crusher connected in sequence;

[0008] An air inlet pipe is provided below the primary crystallization kettle and the secondary crystallization kettle, an air outlet pipe is provided on the top of the primary crystallization kettle and the secondary crystallization kettle, and a water inlet pipe is also provided on the dissolution kettle.

[0009] Furthermore, it also includes a mother liquor collector, and the first solid-liquid separation device is provided with a first mother liquor outlet and a first crystal outlet, the first crystal outlet is connected to the dissolution kettle through a first conveying pipe, the first mother liquor outlet is connected to the mother liquor collector through a second conveying pipe, and is connected to the dissolution kettle through a third conveying pipe.

[0010] Furthermore, the second solid-liquid separation device is provided with a second mother liquor outlet and a second crystal outlet, the second crystal outlet is communicated with the crusher, and the second mother liquor outlet is communicated with the mother liquor collector.

[0011] Furthermore, a reaction kettle is included, and the reaction kettle is connected to the feed pipe of the primary crystallization kettle.

[0012] Furthermore, it also includes a spray washing device, which is located between the second solid-liquid separation device and the crusher.

[0013] Furthermore, it also includes a drying device, which is located between the spray washing device and the crusher.

[0014] Furthermore, the reaction kettle, the primary crystallization kettle, the dissolution kettle and the secondary crystallization kettle are all provided with a stirring device.

[0015] Furthermore, the stirring device is an axial flow stirring device.

[0016] Furthermore, air distribution pipes are provided in the primary crystallization kettle and the secondary crystallization kettle, and the length direction of the air distribution pipes is distributed radially along the primary crystallization kettle and the secondary crystallization kettle; one end of the air inlet pipe is connected to the air supply device, and the other end is connected to the air distribution pipe; a plurality of aeration heads are installed on the air distribution branch pipe.

[0017] Furthermore, the air outlet pipe is communicated with the air supply device, and a one-way valve is provided between the air outlet pipe and the air supply device.

[0018] Furthermore, thermometers are provided at the middle positions of the main bodies of the primary crystallization kettle and the secondary crystallization kettle.

[0019] Furthermore, observation windows are provided on the tops of the primary crystallization kettle and the secondary crystallization kettle.

[0020] The technical solution of the embodiment of the utility model has at least the following advantages and beneficial effects:

[0021] The reagent-grade aluminum chloride crystal production system of the utility model can effectively pass hydrogen chloride gas into the aluminum chloride solution to crystallize aluminum chloride crystals at room temperature by uniformly passing hydrogen chloride gas into the aluminum chloride solution. After the high-purity aluminum chloride obtained by the primary crystallization is redissolved, secondary crystallization is performed under the condition of re-passing hydrogen chloride gas, thereby further improving the purity of the aluminum chloride crystals and realizing the production of reagent-grade aluminum chloride crystals. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following briefly introduces the drawings required for use in the embodiments.

[0023] Figure 1 A production system diagram of reagent-grade aluminum chloride crystals provided in Example 1 of the present utility model;

[0024] Icons: 1-primary crystallization kettle, 2-first solid-liquid separation device, 3-dissolution kettle, 4-secondary crystallization kettle, 5-second solid-liquid separation device, 6-mother liquor collector, 7-crusher, 8-reactor. DETAILED DESCRIPTION

[0025] 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 in conjunction with the drawings in the embodiments of the present invention.

[0026] Example 1

[0027] A reagent-grade aluminum chloride crystal production system comprises a primary crystallization kettle 1, a first solid-liquid separation device 2, a first dissolution kettle 3, a secondary crystallization kettle 4, a second solid-liquid separation device 5 and a crusher 7, which are connected in sequence;

[0028] An air inlet pipe is provided below the primary crystallization kettle 1 and the secondary crystallization kettle 4, an air outlet pipe is provided on one side of the top of the primary crystallization kettle 1 and the secondary crystallization kettle 4, and a feed pipe is provided on the other side; a water inlet pipe is also provided on the dissolution kettle 3.

[0029] The first solid-liquid separation device 2 and the second solid-liquid separation device 5 are both centrifuges.

[0030] This embodiment also includes a mother liquor collector. The first solid-liquid separation device 2 is provided with a first mother liquor outlet and a first crystal outlet. The first crystal outlet is connected to the first dissolving kettle 3 through a first conveying pipe. The first mother liquor outlet is connected to the mother liquor collector 6 through a second conveying pipe and is connected to the dissolving kettle 3 through a third conveying pipe. The dissolving kettle 3 is also provided with a water inlet pipe.

[0031] The second solid-liquid separation device 5 is provided with a second mother liquid outlet and a second crystal outlet. The second crystal outlet is connected to the crusher 7 , and the second mother liquid outlet is connected to the mother liquid collector 6 .

[0032] Open the valve on the feed pipe, and after the feed pipe delivers an appropriate amount of aluminum chloride solution to the primary crystallization kettle 1, open the valve on the air inlet pipe, and after the air inlet pipe introduces an excess amount of hydrogen chloride gas into the primary crystallization kettle 1, the excess hydrogen chloride gas flows out from the air outlet pipe to obtain a primary crystallized aluminum chloride slurry.

[0033] The primary crystallized aluminum chloride slurry is transported to the first solid-liquid separation device 2 for solid-liquid separation to obtain high-purity crystalline aluminum chloride. The high-purity crystalline aluminum chloride obtained by primary crystallization flows out from the first crystal outlet and is transported to the second dissolution kettle 3. The centrifuged mother liquor of the first solid-liquid separation device 2 flows out from the first mother liquor outlet, a part of which is pumped into the mother liquor collector 6 through the second conveying pipe, and the other part is pumped into the dissolution kettle 3 through the third conveying pipe.

[0034] The water inlet pipe adds pure water to the dissolution kettle 3 to completely dissolve the high-purity crystalline aluminum chloride obtained by the primary crystallization, and the re-dissolved aluminum chloride is transported to the secondary crystallization kettle 4. An excess amount of hydrogen chloride gas is also introduced, and the excess hydrogen chloride gas flows out from the gas outlet pipe to obtain a secondary crystallized aluminum chloride slurry with higher purity; the secondary crystallized aluminum chloride slurry is transported to the second solid-liquid separation device 5 for solid-liquid separation, and the centrifuged mother liquor of the second solid-liquid separation device 5 flows out from the second mother liquor outlet into the mother liquor collector. The high-purity crystalline aluminum chloride obtained by the secondary crystallization flows out from the second crystal outlet and is transported to the crusher 7 for drying and crushing to obtain reagent-grade ultra-high-purity aluminum chloride crystals.

[0035] This embodiment further includes a reactor 8, which is connected to the feed pipe of the primary crystallization kettle 1 and is used to add industrial-grade aluminum hydroxide and industrial hydrochloric acid into the reactor 8 for dissolution, and transport the aluminum chloride solution obtained by dissolution to the primary crystallization kettle 1.

[0036] This embodiment further includes a spray washing device, which is located between the second solid-liquid separation device 5 and the crusher 7 and is used to wash the high-purity crystalline aluminum chloride obtained by secondary crystallization separated by the second solid-liquid separation device 5.

[0037] This embodiment further includes a drying device, which is located between the spray washing device and the crusher 7 and is used to dry the washed crystals.

[0038] The reaction kettle 8, the primary crystallization kettle 1, the dissolution kettle 3, and the secondary crystallization kettle 4 of this embodiment are all provided with a stirring device, and the stirring device is an axial flow stirring device.

[0039] Both the primary crystallization kettle 1 and the secondary crystallization kettle 4 are provided with air distribution pipes, and the length direction of the air distribution pipes is distributed along the radial direction of the primary crystallization kettle 1 and the secondary crystallization kettle 4; one end of the air inlet pipe is connected to the air supply device, and the other end is connected to the air distribution pipe; multiple aeration heads are installed on an air distribution pipe.

[0040] The gas outlet pipe of this embodiment is connected to the gas supply device, and a one-way valve is provided between the gas outlet pipe and the gas supply device. The excess hydrogen chloride gas is connected to the hydrogen chloride gas supply pipe through the gas outlet pipe and enters the crystallization kettle for recycling.

[0041] In this embodiment, thermometers are provided at the middle of the main bodies of the primary crystallization kettle 1 and the secondary crystallization kettle 4 to facilitate monitoring of the reaction temperature in the primary crystallization kettle 1 and the secondary crystallization kettle 4.

[0042] In this embodiment, the tops of the primary crystallization kettle 1 and the secondary crystallization kettle 4 are both provided with observation windows, which facilitate the staff to observe the crystallization conditions in the primary crystallization kettle 1 and the secondary crystallization kettle 4 through the observation windows.

[0043] In summary, the production device of reagent-grade aluminum chloride crystals of the present application can make good use of hydrogen chloride gas to obtain ultra-high purity crystalline aluminum chloride that meets reagent-grade analytical purity standards.

Claims

1. A reagent-grade aluminum chloride crystal production system, characterized by: It includes a primary crystallization kettle, a first solid-liquid separation device, a dissolving kettle, a secondary crystallization kettle, a second solid-liquid separation device and a crusher which are connected in sequence; An air inlet pipe is provided below the primary crystallization kettle and the secondary crystallization kettle, an air outlet pipe is provided on the top of the primary crystallization kettle and the secondary crystallization kettle, and a water inlet pipe is also provided on the dissolution kettle.

2. A reagent-grade aluminum chloride crystal production system according to claim 1, characterized in that: It also includes a mother liquor collector, and the first solid-liquid separation device is provided with a first mother liquor outlet and a first crystal outlet, the first crystal outlet is connected to the dissolution kettle through a first conveying pipe, the first mother liquor outlet is connected to the mother liquor collector through a second conveying pipe, and is connected to the dissolution kettle through a third conveying pipe.

3. A reagent-grade aluminum chloride crystal production system according to claim 2, characterized in that: The second solid-liquid separation device is provided with a second mother liquid outlet and a second crystal outlet, the second crystal outlet is communicated with the crusher, and the second mother liquid outlet is communicated with the mother liquid collector.

4. A reagent-grade aluminum chloride crystal production system according to claim 3, characterized in that: The method further comprises a reaction kettle, which is connected to the feed pipe of the primary crystallization kettle.

5. A reagent-grade aluminum chloride crystal production system according to claim 4, characterized in that: It also includes a spray washing device, which is located between the second solid-liquid separation device and the crusher.

6. A reagent-grade aluminum chloride crystal production system according to claim 5, characterized in that: It also includes a drying device, which is located between the spray washing device and the crusher.

7. A reagent-grade aluminum chloride crystal production system according to claim 6, characterized in that: The reaction kettle, the primary crystallization kettle, the dissolution kettle and the secondary crystallization kettle are all provided with a stirring device.

8. A reagent-grade aluminum chloride crystal production system according to claim 7, characterized in that: The stirring device is an axial flow stirring device.

9. A reagent-grade aluminum chloride crystal production system according to claim 8, characterized in that: Air distribution pipes are provided in both the primary crystallization kettle and the secondary crystallization kettle, and the length direction of the air distribution pipes is distributed along the radial direction of the primary crystallization kettle and the secondary crystallization kettle; one end of the air inlet pipe is connected to the air supply device, and the other end is connected to the air distribution pipe; a plurality of aeration heads are installed on the air distribution pipe.

10. A reagent-grade aluminum chloride crystal production system according to claim 9, characterized in that: The air outlet pipe is communicated with the air supply device, and a one-way valve is provided between the air outlet pipe and the air supply device.

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