Production system for separation of zirconium and hafnium by centrifugal extraction based on MIBK method

Abstract

The present invention relates to the field of hydrometallurgical production technology, and discloses a production system for centrifugal extraction and separation of zirconium and hafnium based on the MIBK method, including a centrifugal extraction device, the centrifugal extraction device including an extraction section, a washing section and a stripping section connected in series in sequence, the extraction section, the washing section and the stripping section all including a number of centrifugal extractors used in series; the extraction section is connected with an extractant feed pipe, a liquid feed pipe, an auxiliary extractant feed pipe and a raffinate discharge pipe; the washing section is connected with a detergent feed pipe; the stripping section is connected with a stripping agent feed pipe and a stripping liquid discharge pipe. The present invention solves the technical problems that the existing device for extracting and separating zirconium and hafnium using the MIBK method has a long equilibrium time and a large cost for small-scale customized production.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgical production, and in particular to a production system for separating zirconium and hafnium by centrifugal extraction based on a MIBK method. Background Art

[0002] Zirconium and hafnium are important materials in the nuclear industry. Hafnium is mainly used to make control rods of nuclear reactors due to its large thermal neutron cross section. Zirconium is mainly used to make cladding materials and other structural materials for uranium fuel elements in nuclear reactors due to its small thermal neutron cross section. Hafnium does not exist as a separate mineral in nature, and it always coexists in zirconium ores. Due to the lanthanum contraction of zirconium and hafnium, their atomic radius and ionic radius are similar, and their physical and chemical properties are very similar. It is very difficult to separate them from each other, and they are considered to be one of the most difficult pairs of elements to separate.

[0003] There are three main processes for separating zirconium and hafnium by solvent extraction, namely trialkyl (mixed) amine (N235) extraction and separation, tributyl phosphate (TBP) extraction and separation, and methyl isobutyl ketone (MIBK) extraction and separation. Among them, methyl isobutyl ketone (MIBK) extraction and separation is the process with the largest industrial capacity currently used for separating zirconium and hafnium. However, the MIBK method currently uses tower extraction and separation in industry. The extraction aid ammonium thiocyanate used in this extraction and separation technology is prone to degradation and polymerization during the reaction, and the polymer adheres to the packing of the extraction tower and causes blockage; at the same time, the capacity of the extraction tower is huge, and it takes about a week to adjust the parameters to ensure product stability, which cannot meet the market's growing high-end customized production requirements. Summary of the invention

[0004] The present invention aims to provide a production system for centrifugal extraction and separation of zirconium and hafnium based on the MIBK method, so as to solve the technical problems that the existing device for extracting and separating zirconium and hafnium using the MIBK method has a long equilibrium time and a high cost for small-scale customized production.

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a production system for separating zirconium and hafnium by centrifugal extraction based on the MIBK method, comprising a centrifugal extraction device, the centrifugal extraction device comprising an extraction section, a washing section and a stripping section connected in series in sequence, the extraction section, the washing section and the stripping section all comprising a number of centrifugal extractors used in series; the extraction section is connected with an extractant feed pipe, a liquid feed pipe, an auxiliary extractant feed pipe and a raffinate discharge pipe; the washing section is connected with a detergent feed pipe; the stripping section is connected with a stripping agent feed pipe and a stripping liquid discharge pipe.

[0006] The principles and advantages of this solution are:

[0007] The inventor of this scheme introduced centrifugal extraction technology into the method of separating zirconium and hafnium using MIBK, and invented a production system for separating zirconium and hafnium by centrifugal extraction based on the MIBK method. The system uses a centrifugal extractor as an extraction device and a cascade extraction process to ensure the full separation of zirconium and hafnium, and can prepare zirconium oxide and hafnium oxide with higher purity. Compared with the current tower extraction technology, the centrifugal extractor used in the centrifugal extraction technology has a small liquid storage volume, a short residence time, a wide range of adaptable flow ratios, a fast mass transfer equilibrium speed, high mass transfer stage efficiency, easy start and stop, and can quickly reach steady-state operation after starting. When it is necessary to change production parameters or start production, it only takes 3-4 hours to achieve balanced and stable production, which greatly shortens the production time and reduces production losses, and can promptly meet customers' small-batch and different-purity zirconium and hafnium production needs.

[0008] Preferably, as an improvement, the centrifugal extractor comprises an upper shell and a lower shell fixedly connected, the lower shell comprises an inner shell and an outer shell fixedly connected to the outer layer of the inner shell, the outer shell and the inner shell form a cavity, the lower portion of the outer shell is provided with a water outlet, and the upper portion is provided with a water inlet.

[0009] In the present application, the casing of the centrifugal extractor is configured as a jacketed structure, and cooling water can be introduced from the water inlet during use to ensure that the reaction temperature of the entire system is low, so as to prevent the extraction aid from being degraded and polymerized during the extraction process, causing pipeline blockage or accumulation on the drum, destroying the dynamic balance of the centrifugal extractor, increasing the friction resistance of the centrifugal extractor, and reducing the processing capacity of the centrifugal extractor.

[0010] Preferably, as an improvement, a light phase liquid outlet and a heavy phase liquid outlet are respectively provided on both sides of the upper end of the inner shell of the centrifugal extractor, and a light phase liquid inlet and a heavy phase liquid inlet are respectively provided on both sides of the middle end of the inner shell, and both the outlet and the inlet pass through the outer shell.

[0011] In the present application, the inner shell of the centrifugal extractor is a specific extraction reaction site, and the reaction materials are mixed and separated in the centrifugal extractor through the inlet and outlet.

[0012] Preferably, as an improvement, the number of centrifugal extractors in the extraction section is 10-15, the number of centrifugal extractors in the washing section is 5-10, and the number of centrifugal extractors in the stripping section is 3-5.

[0013] In this application, different reaction levels can be set for the extraction section, washing section and centrifugal section according to the specific product requirements to be produced, so as to ensure the quality of the product. At the same time, the reaction level can be flexibly switched according to the specific product requirements to meet the needs of different customers.

[0014] Preferably, as an improvement, the light phase liquid inlet of the first-stage centrifugal extractor in the extraction section is connected to the extractant feed pipe, and the heavy phase liquid outlet is connected to the raffinate discharge pipe; the heavy phase liquid inlet of the last-stage centrifugal extractor in the extraction section is connected to the auxiliary extraction agent feed pipe, and the light phase liquid inlet is connected to the feed liquid feed pipe.

[0015] In the present application, the function of the extraction section is to extract almost all hafnium elements and a small amount of zirconium elements in the feed liquid into the organic phase by countercurrent extraction, thereby playing the role of preliminary separation of zirconium and hafnium.

[0016] Preferably, as an improvement, the heavy phase liquid inlet of the last-stage centrifugal extractor of the washing section is connected to a detergent feed pipe, and the detergent feed pipe includes a hydrochloric acid feed pipe and a stripping liquid discharge branch pipe.

[0017] In the present application, the function of the washing section is to wash out the zirconium element that enters the organic phase during extraction from the organic phase, thereby further separating zirconium and hafnium.

[0018] Preferably, as an improvement, the heavy phase outlet of the first-stage centrifugal extractor in the stripping section is connected to a stripping liquid discharge pipe, and the stripping liquid is connected to the stripping liquid discharge branch pipe after passing through a pump and a flow controller; the heavy phase liquid inlet of the last-stage centrifugal extractor in the stripping section is provided with a stripping agent feed pipe.

[0019] In the present application, the function of the stripping section is to strip the hafnium element from the organic phase to facilitate subsequent further processing to obtain high-purity hafnium oxide.

[0020] Preferably, as an improvement, the extractant feed pipe, the liquid feed pipe, the auxiliary extractant feed pipe, the hydrochloric acid feed pipe

[0021] The tube and the stripping agent feeding tube are both provided with a flow regulating unit, a flow monitoring unit, a temperature measuring unit and a heat exchanging unit.

[0022] In this application, all feed pipes are equipped with flow control units and temperature measurement units, the purpose of which is to facilitate the control of the feed flow of each raw material in the system. At the same time, the temperature of the feed liquid can also be controlled by the heat exchange unit, and the reaction temperature can be further controlled to prevent the polymerization and decomposition of the extraction aid.

[0023] Preferably, as an improvement, the present solution also includes a DCS automatic control system, which is used to control the centrifugal extraction device. The DCS automatic control system includes a DCS control center and a control module electrically connected to the DCS control center, and the control module includes a centrifugal extraction machine control module, a flow regulation control module, a flow monitoring control module, a temperature measurement control module and a heat exchange control module.

[0024] In this application, the DCS automatic control system can realize decentralized detection and centralized control of the entire system. The detailed parameters of each link of the system are collected through the control module and fed back to the control center. The operator then issues operating instructions through the control center based on the collected information to realize automated production and management.

[0025] Preferably, as an improvement, the centrifugal extractor control module is used to control and adjust the speed of the centrifugal extractor; the flow regulation control module is used to control the opening and closing of the flow regulation unit and the flow control; the flow monitoring control module is used to receive the monitoring data of the flow monitoring unit; the temperature measurement control module is used to receive the measurement data of the temperature measurement unit, and the heat exchange control module is used to control the opening and closing of the heat exchange unit and the temperature control.

[0026] In the present application, each control module can realize data feedback and control of the corresponding operating unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic structural diagram of the extraction section in the production system for separating zirconium and hafnium by centrifugal extraction based on the MIBK method of the present invention;

[0028] Figure 2 It is a schematic structural diagram of the washing section in the production system for separating zirconium and hafnium by centrifugal extraction based on the MIBK method of the present invention;

[0029] Figure 3 It is a schematic structural diagram of the stripping section in the production system for separating zirconium and hafnium by centrifugal extraction based on the MIBK method of the present invention;

[0030] Figure 4 It is a cross-sectional view of a centrifugal extractor in a production system for centrifugal extraction and separation of zirconium and hafnium based on the MIBK method of the present invention;

[0031] Figure 5 The present invention is a schematic structural diagram of a production system for centrifugal extraction and separation of zirconium and hafnium based on the MIBK method. DETAILED DESCRIPTION

[0032] The following is further described in detail through specific implementation methods:

[0033] The reference numerals in the drawings of the specification include: centrifugal extractor 1, extractant feed pipe 2, liquid feed pipe 3, auxiliary extractant feed pipe 4, hydrochloric acid feed pipe 5, stripping agent feed pipe 6, raffinate discharge pipe 7, stripping liquid discharge pipe 8, stripping liquid discharge branch pipe 9, process water pipe 10, flow regulating unit 11, flow monitoring unit 12, temperature measuring unit 13, heat exchange unit 14, control valve 15, cooling water inlet pipe 16, cooling water outlet pipe 17, inner shell 101, outer shell 102, light phase liquid inlet 103, light phase liquid outlet 104, heavy phase liquid inlet 105, heavy phase liquid outlet 106, water inlet 107, water outlet 108, upper shell 109, motor 110, centrifugal shaft 111, axial magnetic bearing 112, upper magnet 1121, lower magnet 1122, magnetic coupling 113 , inner magnet 1131 , outer magnet 1132 , protective cover 1133 , isolation cover 1134 , radial magnetic bearing 114 , force-bearing part 115 , and rotating drum 116 .

[0034] Example

[0035] Basically as attached Figure 1-5 As shown in the figure, the production system for separating zirconium and hafnium by centrifugal extraction based on the MIBK method includes a centrifugal extraction device and a DCS automatic control system for controlling the centrifugal extraction device. The centrifugal extraction device is basically as shown in the figure. Figure 1-3 The invention comprises an extraction section, a washing section and a stripping section. The extraction section, the washing section and the stripping section are all composed of a plurality of centrifugal extractors 1. The number of centrifugal extractors 1 in the extraction section is 10-15, the number of centrifugal extractors 1 in the washing section is 5-10, and the number of centrifugal extractors 1 in the stripping section is 3-5. The number of centrifugal extractors 1 in the extraction section, the washing section and the stripping section in this scheme can be adaptively selected according to different product requirements.

[0036] The structure of the centrifugal extractor 1 is shown in the attached figure. Figure 4 As shown, its shell is a jacket type, including an upper shell 109 and a lower shell, and the upper shell and the lower shell are fixedly connected by a flange. The lower shell includes an inner shell 101 and an outer shell 102 fixedly welded to the outer layer of the inner shell 101. The outer shell 102 and the inner shell 101 form a cavity, which can be used to store circulating cooling or heating liquid. The upper part of the outer shell 102 is provided with a water outlet 108, and the lower part is provided with a water inlet 107. In this embodiment, the water outlet pipes of all centrifugal extractors 1 are connected to a cooling water outlet pipe 17, and the water inlet 107 is connected to a cooling water inlet pipe 16, and the cooling water inlet pipe 16 is connected to a unified cooling water source (not shown in the drawings).

[0037] A light phase liquid outlet 104 and a heavy phase liquid outlet 106 are respectively provided on both sides of the upper end of the inner shell 101 of the centrifugal extractor 1, and a light phase liquid inlet 103 and a heavy phase liquid inlet 105 are respectively provided on both sides of the middle end of the inner shell 101. The light phase liquid outlet 104, the heavy phase liquid outlet 106, the light phase liquid inlet 103 and the heavy phase liquid inlet 105 all pass through the outer shell 102 and are connected to other pipelines.

[0038] The centrifugal extractor also includes a centrifugal shaft 111 and a drum 116. The drum 116 is arranged inside the inner shell, and the centrifugal shaft 111 is vertically arranged and fixedly connected to the drum 116. One end of the centrifugal shaft 111 is located in the drum 116, and the other end extends out of the upper shell 109. A force-bearing part 115 connected to the axial magnetic suspension bearing 112 and the centrifugal shaft 111 is provided above the upper shell 109. The axial magnetic suspension bearing 112 includes an upper magnet 1121 and a lower magnet 1122. The force-bearing part 115 is located between the upper magnet 1121 and the lower magnet 1122. A magnetic coupling 113 and a motor 110 are also provided above the upper magnet 1121. The magnetic coupling 113 includes an inner magnet 1131, an outer magnet 1132, a protective cover 1133 and an isolation cover 1134. The inner magnet 1131 is fixed on the centrifugal shaft 111, and the outer magnet 1132 is arranged on the outer peripheral side of the inner magnet 1131. The isolation cover 1134 is arranged between the inner magnet 1131 and the outer magnet 1132, and is used to separate the inner magnet 1131 and the outer magnet 1132. The protective cover 1133 is arranged on the outer layer of the outer magnet 1132, and the protective cover 1133 is fixedly connected to the motor 110. The output end of the motor 110 passes through the protective cover 1133 and is connected to the outer magnet 1132. The motor 110 adopts a variable frequency motor. The magnetic coupling 113 is used to transmit torque to the centrifugal shaft 111 to drive the centrifugal shaft 111 to rotate.

[0039] A pair of radial magnetic bearings 114 are respectively provided at the upper and lower parts of the inner shell of the centrifugal extractor and the drum 116 to control the radial displacement of the upper and lower parts of the drum 116. The radial magnetic bearings 114 include a stator and a rotor, wherein the stator is provided on the inner shell 101 and the rotor is provided on the drum 116.

[0040] In this scheme, the extraction section, washing section and stripping section are connected in series in sequence, and the centrifugal extractors 1 of the extraction section, washing section and stripping section are also connected in series. Specifically, the light phase liquid outlet 104 of the first-stage centrifugal extractor 1 in the extraction section is connected to the light phase liquid inlet 103 of the first-stage centrifugal extractor 1 in the extraction section, and the heavy phase liquid outlet 106 of the first-stage centrifugal extractor 1 in the extraction section is connected to the heavy phase liquid inlet 105 of the first-stage centrifugal extractor 1 in the extraction section. The light phase liquid outlet 104 of the last-stage centrifugal extractor 1 in the extraction section is connected to the light phase liquid inlet 103 of the first-stage centrifugal extractor 1 in the washing section, and the heavy phase liquid outlet 106 of the first-stage centrifugal extractor 1 in the washing section is connected to the heavy phase liquid inlet 105 of the last-stage centrifugal extractor 1 in the extraction section. The stripping section is set up the same as above.

[0041] More specifically, the light phase liquid inlet 103 of the first-stage centrifugal extractor 1 of the extraction section is connected with an extractant feed pipe 2, and the heavy phase liquid outlet 106 is connected with a raffinate discharge pipe 7, and the raffinate discharge pipe 7 is connected with a subsequent processing device (not shown in the figure), which is used to further process the raffinate to obtain zirconium oxide. The light phase liquid inlet 103 of the last-stage centrifugal extractor 1 of the extraction section is not only connected to the light phase liquid outlet 104 of the previous-stage centrifugal extractor 1, but also connected with a liquid feed pipe 3. At the same time, the heavy phase liquid inlet 105 of the last-stage centrifugal extractor 1 of the extraction section is not only connected to the heavy phase liquid outlet 106 of the first-stage centrifugal extractor 1 of the washing section, but also connected with an extractant feed pipe 4.

[0042] The heavy phase liquid inlet 105 of the last centrifugal extractor 1 of the washing section is connected to a detergent feed pipe, which includes a hydrochloric acid feed pipe 5 and a stripping liquid discharge branch pipe 9. A process water pipe 10 is connected to the hydrochloric acid feed pipe 5, and the process water pipe 10 is used to dilute the hydrochloric acid concentration in the present application. The stripping liquid discharge branch pipe 9 is connected to the heavy phase liquid outlet 106 of the first centrifugal extractor 1 of the stripping section.

[0043] The heavy phase liquid outlet 106 of the first-stage centrifugal extractor 1 of the stripping section is also provided with a stripping liquid discharge pipe 8, and the stripping liquid discharge pipe 8 is connected to a stripping liquid treatment device (not shown in the figure), and the stripping liquid treatment device is used to further treat the stripping liquid, and finally obtain hafnium oxide. In this scheme, most of the stripping liquid flows out from the stripping liquid discharge pipe 8 and enters the stripping liquid treatment device, and a small part enters the stripping liquid discharge branch pipe 9 through a pump and a flow controller and flows out and is mixed with hydrochloric acid as a detergent. The heavy phase liquid inlet 105 of the last-stage centrifugal extractor 1 of the stripping section is provided with a stripping agent feed pipe 6, and the heavy phase liquid outlet 106 is connected to a stripping raffinate treatment device, and the stripping raffinate treatment device is used to recover the extractant and auxiliary extractant contained in the stripping raffinate.

[0044] It should be noted that, in this embodiment, all feed pipes including the extractant feed pipe 2, the liquid feed pipe 3, the auxiliary extractant feed pipe 4, the hydrochloric acid feed pipe 5 and the stripping agent feed pipe 6 are provided with a flow regulating unit 11, a flow monitoring unit 12, a temperature measuring unit 13 and a heat exchange unit 14, and the heat exchange unit 14 is also connected to a cooling water inlet pipe 16 and a cooling water outlet pipe 17, and a control valve 15 is provided on the cooling water inlet pipe 16. It should be noted that the cooling water inlet pipe 16 connected to the centrifugal extractor 1 is also provided with a control valve 15.

[0045] In this embodiment, the DCS automatic control system includes a DCS control center and a control module electrically connected to the DCS control center, and the control module includes a centrifugal extractor control module, a flow regulating control module, a flow monitoring control module, a temperature measurement control module and a heat exchange control module. The centrifugal extractor control module is used to control and adjust the speed of the motor 110 in the centrifugal extractor 1, the flow regulating control module is used to control the opening and closing of the flow regulating unit 11; the flow monitoring control module is used to receive the monitoring data of the flow monitoring unit 12; the temperature measurement control module is used to receive the measurement data of the temperature measurement unit 13, and the heat exchange control module is used to control the opening and closing of the heat exchange unit 14. The control module also includes a control valve control module for controlling the opening and closing of the control valve 15.

[0046] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A production system for separating zirconium and hafnium by centrifugal extraction based on the MIBK method, characterized by: The invention comprises a centrifugal extraction device, which comprises an extraction section, a washing section and a stripping section connected in series in sequence, wherein the extraction section, the washing section and the stripping section all comprise a number of centrifugal extractors used in series; the extraction section is connected with an extractant feed pipe, a liquid feed pipe, an auxiliary extractant feed pipe and a raffinate discharge pipe; the washing section is connected with a detergent feed pipe; the stripping section is connected with a stripping agent feed pipe and a stripping liquid discharge pipe; The light phase liquid inlet of the first-stage centrifugal extractor of the extraction section is connected to the extractant feed pipe, and the heavy phase liquid outlet is connected to the raffinate discharge pipe; the heavy phase liquid inlet of the last-stage centrifugal extractor of the extraction section is not only connected to the heavy phase liquid outlet of the first-stage centrifugal extractor of the washing section, but also connected to the auxiliary extraction agent feed pipe, and the light phase liquid inlet is connected to the feed liquid feed pipe; The heavy phase liquid inlet of the last centrifugal extractor of the washing section is connected to a detergent feed pipe, the detergent feed pipe includes a hydrochloric acid feed pipe and a stripping liquid discharge branch pipe, and the stripping liquid discharge branch pipe is connected to the heavy phase liquid outlet of the first centrifugal extractor of the stripping section; The heavy phase outlet of the first-stage centrifugal extractor in the stripping section is connected to a stripping liquid discharge pipe, and the stripping liquid is connected to the stripping liquid discharge branch pipe after passing through a pump and a flow controller. The stripping liquid enters the stripping liquid discharge branch pipe, flows out, and is mixed with hydrochloric acid as a detergent; the heavy phase liquid inlet of the last-stage centrifugal extractor in the stripping section is provided with a stripping agent feed pipe.

2. The production system for separating zirconium and hafnium by centrifugal extraction based on the MIBK method according to claim 1, characterized in that: The centrifugal extractor comprises an upper shell and a lower shell which are fixedly connected. The lower shell comprises an inner shell and an outer shell which is fixedly connected to the outer layer of the inner shell. A cavity is formed between the outer shell and the inner shell. A water outlet is provided at the lower part of the outer shell and a water inlet is provided at the upper part.

3. The production system for separating zirconium and hafnium by centrifugal extraction based on the MIBK method according to claim 2, characterized in that: The upper ends of the inner shell of the centrifugal extractor are provided with a light phase liquid outlet and a heavy phase liquid outlet respectively on both sides, and the middle ends of the inner shell are provided with a light phase liquid inlet and a heavy phase liquid inlet respectively on both sides, and both the outlet and the inlet pass through the outer shell.

4. The production system for separating zirconium and hafnium by centrifugal extraction based on the MIBK method according to claim 3, characterized in that: The number of centrifugal extractors in the extraction section is 10-15, the number of centrifugal extractors in the washing section is 5-10, and the number of centrifugal extractors in the stripping section is 3-5.

5. The production system for separating zirconium and hafnium by centrifugal extraction based on the MIBK method according to claim 4, characterized in that: The extractant feed pipe, liquid feed pipe, auxiliary extractant feed pipe, hydrochloric acid feed pipe and stripping agent feed pipe are all provided with a flow regulating unit, a flow monitoring unit, a temperature measuring unit and a heat exchange unit.

6. The production system for separating zirconium and hafnium by centrifugal extraction based on the MIBK method according to claim 5, characterized in that: It also includes a DCS automatic control system, which is used to control the centrifugal extraction device. The DCS automatic control system includes a DCS control center and a control module electrically connected to the DCS control center. The control module includes a centrifugal extraction machine control module, a flow regulation control module, a flow monitoring control module, a temperature measurement control module and a heat exchange control module.

7. The production system for separating zirconium and hafnium by centrifugal extraction based on the MIBK method according to claim 6, characterized in that: The centrifugal extractor control module is used to control and adjust the rotation speed of the centrifugal extractor; the flow regulation control module is used to control the opening and closing of the flow regulation unit and the flow control; the flow monitoring control module is used to receive the monitoring data of the flow monitoring unit; the temperature measurement control module is used to receive the measurement data of the temperature measurement unit, and the heat exchange control module is used to control the opening and closing of the heat exchange unit and the temperature control.

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