Device for regenerating spent mercuric chloride catalyst by molten salt electrolysis and recovering mercury

Abstract

The present invention relates to the field of waste mercury catalyst recovery, and discloses a device for molten salt electrolysis regeneration and mercury recovery of waste mercuric chloride catalyst, the device comprising a material bin, a height-adjustable stirring mechanism is provided at the top of the inner cavity of the material bin, and a heating mechanism and a retractable electrolysis mechanism are also provided in the material bin. The stirring mechanism of the device is height-adjustable, and after the stirring is completed, the stirring mechanism can be raised to separate from the material to avoid interference with the material in the material bin, and the retractable electrolysis mechanism can meet the different heights of the material in the material bin, and has strong applicability and simple operation, and can realize mercury recovery and activated carbon regeneration of non-mercury chloride catalyst at the same time, with high efficiency.

Description

Technical Field

[0001] The invention relates to the field of waste mercury catalyst recovery, and in particular to a device for molten salt electrolysis regeneration of waste mercuric chloride catalyst and mercury recovery. Background Art

[0002] Mercury catalyst is an indispensable part of the production of polyvinyl chloride by the calcium carbide process. It is used as a catalyst for the synthesis of vinyl chloride from acetylene and hydrogen chloride gas in the production of polyvinyl chloride. The production of mercury catalyst uses activated carbon as a carrier and mercuric chloride as an active substance, and the mercuric chloride is loaded on the surface of the activated carbon. After a certain period of use, the activity of the mercury catalyst decreases and needs to be replaced. The replaced waste mercury catalyst generally still contains 2-5% mercuric chloride. Because mercuric chloride is highly toxic, highly volatile, and easily soluble in water, if the replaced mercury catalyst is directly discarded or piled up, it will inevitably cause serious mercury pollution and create major safety hazards.

[0003] According to the "Methods for the Treatment and Disposal of Waste Mercury Catalysts (GB / T 36382-2008)", the current harmless treatment of waste mercury catalysts mainly adopts distillation and oxygen-controlled dry distillation. The distillation method is to add quicklime, sodium hydroxide, etc. to convert the mercury in various valence states in the waste mercury catalyst into similar substances (mostly mercuric oxide) that are extremely easy to decompose, volatilize, and collect. The mercuric oxide is decomposed into elemental mercury and oxygen by heat, and the elemental mercury vapor is quenched to achieve the recovery of mercury in the waste mercury catalyst. However, this method does not achieve the activation and regeneration of activated carbon, and because quicklime, sodium hydroxide and other substances are introduced in the pretreatment, a large amount of calcium carbonate, calcium oxide, sodium carbonate and other powders are attached to the surface of the waste mercury catalyst after the distillation process, which makes the activated carbon seriously inactivated, and thus makes it difficult to reuse the activated carbon. The oxygen-controlled dry distillation method uses the sublimation of mercuric chloride at high temperature, and the coking temperature of activated carbon is lower than the sublimation temperature of mercuric chloride. Under the conditions of inert gas atmosphere and negative pressure sealing, mercuric chloride and activated carbon can be recovered at the same time. However, since the mixture of mercuric chloride vapor and mercury vapor is extremely corrosive, existing metal / metal alloy materials cannot be used, which limits its industrial application.

[0004] In addition, there are existing chemical methods that reactivate activated carbon without separating the activated carbon from the mercuric chloride in the waste mercury catalyst, and eliminate carbon deposition and catalyst poisoning to achieve regeneration. For example, patent CN104138767A discloses a method for regenerating waste mercuric chloride catalyst after three-stage activation, that is, firstly putting the waste mercury catalyst into a regeneration activation furnace, low-temperature carbonization at 100-200°C, then adding carbon dioxide and water vapor to the activation regeneration furnace for steam activation, and finally using dilute hydrochloric acid to chemically activate the waste mercury catalyst to remove trace impurities. This method can effectively recycle and reuse the waste mercury catalyst, but there are problems such as the volatilization of mercuric chloride by heat and the large consumption of chemical reagents during the activation process. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems existing in the prior art and to provide a device for electrolyzing and regenerating waste mercuric chloride catalyst molten salt and recovering mercury.

[0006] In order to achieve the above-mentioned purpose, the present invention provides a device for electrolyzing and regenerating waste mercuric chloride catalyst molten salt and recovering mercury, the device comprising a material bin, the top of the inner cavity of which is provided with a height-adjustable stirring mechanism, and a heating mechanism and a retractable electrolysis mechanism are also provided in the material bin.

[0007] Preferably, one side wall of the material bin is detachably connected to the main body of the material bin via a screw structure.

[0008] Preferably, a feeding room and a conveying pipe are sequentially provided at the top of the material bin, and the material bin and the feeding room are both connected to the conveying pipe.

[0009] Preferably, a sealing structure is provided at the feed inlet of the feed room.

[0010] Preferably, the stirring mechanism includes a motor located outside the feeding room, a shaft located in the feeding pipe, a shaft telescopic rod sleeved outside the shaft, and a rotating blade located at the bottom of the shaft telescopic rod.

[0011] Preferably, the heating mechanism is located at the bottom of the inner cavity of the material bin, and the heating mechanism includes a heating chamber, a sleeve located in the heating chamber, a metal tube located in the sleeve and an electromagnetic coil wound on the metal tube, and a heat dissipation metal rod is provided outside the heating chamber.

[0012] Preferably, the electrolysis mechanism comprises an electrode located in the material bin, an electric conductive wire connected to the electrode, a telescopic structure for controlling the length of the electric conductive wire, and a power source connected to the electric conductive wire;

[0013] Preferably, a weighing meter is provided on the conductive wire connected to the cathode of the electrode, and the weighing meter is located outside the material bin.

[0014] Preferably, the telescopic structure includes an adjusting chamber and a control circuit installed in the side wall of the adjusting chamber, the conductive wire is passed through the adjusting chamber, the part of the conductive wire located in the adjusting chamber is spiral-shaped, a mechanical rod is provided in the adjusting chamber, a telescopic button is provided on the outside of the adjusting chamber, and the mechanical rods are distributed on both sides of the conductive wire.

[0015] It can be seen from the above technical scheme of the present invention that in the device for molten salt electrolysis regeneration and mercury recovery of waste mercuric chloride catalyst of the present invention, the height of the stirring mechanism is adjustable, and the stirring mechanism can be raised to separate from the material after the stirring is completed to avoid interference with the material in the material bin, and the retractable electrolysis mechanism can meet the different heights of the material in the material bin, has strong applicability, is easy to operate, and can realize mercury recovery and activated carbon regeneration of non-mercuric chloride catalyst at the same time, with high efficiency.

[0016] In a preferred embodiment, the sealing structure of the present invention can improve the sealing performance of the material bin and effectively prevent material leakage. After the electrolysis of the material in the material bin is completed, the screw structure can be opened to take out the material for separation of the activated activated carbon and the molten salt. The operation is simple and convenient. The weighing instrument can determine whether mercury is electrolyzed on the electrode by the change in weight and observe the progress of the electrolysis reaction. The heating mechanism adopts electromagnetic heating with high thermal efficiency, so that the heat can effectively heat the molten salt and shorten the experimental cycle.

[0017] Other advantages of the present invention and the technical effects of the preferred embodiments will be further described in the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0019] Figure 1 It is a device for regenerating waste mercuric chloride catalyst molten salt electrolysis and recovering mercury in the present invention;

[0020] Figure 2 yes Figure 1 The heating mechanism in the device for molten salt electrolysis regeneration of spent mercuric chloride catalyst and mercury recovery shown;

[0021] Figure 3 yes Figure 1 The telescopic structure in the device for molten salt electrolysis regeneration of spent mercuric chloride catalyst and mercury recovery is shown.

[0022] Description of Reference Numerals

[0023] 1Material warehouse 2Feeding room

[0024] 3 sealing structure 4 shaft rod

[0025] 5-conveying pipe 6-axis telescopic rod

[0026] 7 Power Supply 8 Computer

[0027] 9 telescopic structure 10 weighing instrument

[0028] 11 cylinder 12 conductive wire

[0029] 13 electrodes 14 motor

[0030] 15 Rotating blades 16 Screw mechanism

[0031] 17 Heating mechanism 18 Telescopic button

[0032] 19 mechanical rod 20 control circuit

[0033] 21 heat dissipation metal rod 22 electromagnetic coil

[0034] 23 casing 24 metal tube

[0035] 25 temperature control feedback circuit 26 heater DETAILED DESCRIPTION

[0036] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0037] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0038] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connection" and "installation" should be understood in a broad sense. For example, the connection can be a direct connection or an indirect connection through an intermediate medium, and can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] The present invention provides a device for regenerating waste mercuric chloride catalyst by molten salt electrolysis and recovering mercury, such as Figure 1As shown, the device includes a material bin 1, and a height-adjustable stirring mechanism is provided at the top of the inner cavity of the material bin 1. A heating mechanism 17 and a retractable electrolysis mechanism are also provided in the material bin 1. When in use, molten salt is added into the material bin 1, and the heating mechanism 17 is turned on to heat the molten salt to form a molten salt solution. Then, the waste mercuric chloride catalyst is added into the material bin 1, and the stirring mechanism is lowered and immersed in the material. After the material in the material bin 1 is fully mixed by the stirring mechanism, the stirring mechanism is raised and separated from the material; the material is electrolyzed by the electrolysis mechanism, and after the electrolysis is completed, the electrolyte is taken out for solid-liquid separation to obtain activated carbon and recover metallic mercury. The device has strong applicability and is easy to operate. It can realize the simultaneous recovery of mercury and regeneration of activated carbon for non-mercuric chloride catalysts with high efficiency.

[0040] According to a preferred embodiment of the present invention, one side wall of the material bin 1 is detachably connected to the main body of the material bin 1 through a screw structure 16. After the electrolysis of the material in the material bin 1 is completed, the screw structure 16 can be opened to take out the material for separation of activated activated carbon and molten salt, which is easy and convenient to operate.

[0041] According to another preferred embodiment of the present invention, a feeding room 2 and a conveying pipe 5 are sequentially provided at the top of the material bin 1, and both the material bin 1 and the feeding room 2 are connected to the conveying pipe 5; further, a sealing structure 3 is provided at the feeding port of the feeding room 2, and the sealing structure 3 can improve the sealing performance of the material bin 1 and effectively prevent material leakage.

[0042] The present invention has no particular limitation on the structure of the stirring mechanism, as long as the stirring mechanism can fully stir the materials in the material bin 1. Preferably, the stirring mechanism includes a motor 14 located outside the feed room 2, a shaft rod 4 located in the feed pipe 5, a shaft telescopic rod 6 sleeved outside the shaft rod 4, and a rotating blade 15 located at the bottom of the shaft telescopic rod 6. When the stirring mechanism is used, the shaft telescopic rod 6 is extended to allow the rotating blade 15 to be immersed in the material, and the rotating blade 15 is driven to rotate by the motor 14 to stir the material in the material bin 1. After the material is evenly mixed, the rotating blade 15 is lifted to the top of the material bin 1 by shortening the shaft telescopic rod 6.

[0043] The present invention has no particular limitation on the structure of the heating mechanism, as long as the heating mechanism can heat the material in the material bin 1. Figure 2As shown, the heating mechanism 17 is located at the bottom of the inner cavity of the material bin 1. The heating mechanism 17 includes a heating cavity, a sleeve 23 located in the heating cavity, a metal tube 24 located in the sleeve 23, and an electromagnetic coil 22 wound on the metal tube 24. A heat dissipation metal rod 21 is provided outside the heating cavity. By controlling the heater 26 to change the circuit voltage frequency, the high-speed changing current passes through the electromagnetic coil 22 to form a high-speed changing magnetic field. The magnetic lines of force cut the metal tube 24 to achieve electromagnetic heating, and the heat is transferred to the heat dissipation metal rod 21 through thermal radiation and thermal convection, so that the heating mechanism 17 heats the material in the material bin 1. In addition, a temperature control feedback circuit 25 can be provided between the heater 26 and the sleeve 23 to achieve constant temperature timing of heating and ensure the smooth and safe operation of the heating mechanism 17. Compared with common resistance heating, electromagnetic heating has a high thermal efficiency (up to 95% or more), so that the heat can effectively heat the molten salt and shorten the experimental cycle.

[0044] The present invention has no particular limitation on the structure of the electrolysis mechanism, as long as the electrolysis mechanism can electrolyze the material in the material bin 1. Preferably, the electrolysis mechanism includes an electrode 13 located in the material bin 1, an electrically conductive wire 12 connected to the electrode 13, a telescopic structure 9 for controlling the length of the electrically conductive wire 12, and a power supply 7 connected to the electrically conductive wire 12. The voltage, current, and frequency of the power supply 7 are controlled by a computer 8, and the current passes through the telescopic structure 9 and the electrically conductive wire 12 to reach the electrode 13 to achieve electrolysis. The electrode 13 is set as a perforated cylindrical sheet to increase the contact area between the electrode 13 and the material.

[0045] Furthermore, a weighing instrument 10 is provided on the conductive wire 12 connected to the cathode of the electrode 13, and the weighing instrument 10 is located outside the material bin 1. The weighing instrument 10 can judge whether mercury is electrolyzed on the electrode 13 by the change in weight. In addition, a cylinder 11 for taking and placing the electrode 13 can be provided on the material bin 1, and the diameter of the electrode 13 is slightly smaller than the diameter of the cylinder 11, so as to facilitate the replacement of the electrode 13.

[0046] More preferably, if Figure 3 As shown, the telescopic structure 9 includes an adjustment chamber and a control circuit 20 installed in the side wall of the adjustment chamber. The conductive wire 12 is inserted into the adjustment chamber. The portion of the conductive wire 12 located in the adjustment chamber is spiral. A mechanical rod 19 is provided in the adjustment chamber. A telescopic button 18 is provided on the outside of the adjustment chamber. The mechanical rod 19 is distributed on both sides of the conductive wire 12. The control circuit 20 is adjusted to be tight by moving the telescopic button 18 left and right, so that the mechanical rod 19 can swing up and down, thereby controlling the length of the conductive wire 12 in the material bin 1, and finally adjusting the relative distance between the electrode 13 and the material.

[0047] According to a most preferred embodiment of the present invention, Figure 1As shown, it includes a material bin 1, and a feeding room 2 and a conveying pipe 5 are provided at the top of the material bin 1 in sequence. The material bin 1 and the feeding room 2 are both connected to the conveying pipe 5, and a sealing structure 3 is provided at the feeding port of the feeding room 2; one side wall of the material bin 1 is detachably connected to the main body of the material bin 1 through a screw structure 16. The stirring mechanism includes a motor 14 located outside the feeding room 2, a shaft rod 4 located in the conveying pipe 5, an axial telescopic rod 6 sleeved on the outside of the shaft rod 4, and a rotating blade 15 located at the bottom of the axial telescopic rod 6; the heating mechanism 17 is located at the bottom of the inner cavity of the material bin 1, the heating mechanism 17 includes a heating chamber, a sleeve 23 located in the heating chamber, a metal tube 24 located in the sleeve 23, and an electromagnetic coil 22 wound on the metal tube 24, a heat dissipation metal rod 21 is provided outside the heating chamber, and a temperature control feedback circuit 25 is provided between the heater 26 and the sleeve 23; the electrolysis mechanism includes an electrode 1 located in the material bin 1 3. The conductive wire 12 connected to the electrode 13, the telescopic structure 9 for controlling the length of the conductive wire 12 and the power supply 7 connected to the conductive wire 12, the conductive wire 12 connected to the cathode of the electrode 13 is provided with a weighing instrument 10, and the weighing instrument 10 is located outside the material bin 1; the telescopic structure 9 includes a regulating chamber and a control circuit 20 installed in the side wall of the regulating chamber, the conductive wire 12 is passed through the regulating chamber, the part of the conductive wire 12 located in the regulating chamber is spiral, a mechanical rod 19 is provided in the regulating chamber, and a telescopic button 18 is provided outside the regulating chamber, and the mechanical rod 19 is distributed on both sides of the conductive wire 12. The process of using the device for molten salt electrolysis regeneration of waste mercuric chloride catalyst and mercury recovery may include the following steps:

[0048] 1. Add molten salt from the feed room 2 into the material bin 1 through the feed pipe 5, close the sealing structure 3, and turn on the heater 26 of the heating mechanism 17 to heat the molten salt to form a molten salt solution;

[0049] 2. Open the sealing structure 3 and add the waste mercuric chloride catalyst from the feeding room 2 into the material bin 1. Extend the shaft telescopic rod 6 to immerse the rotating blade 15 into the material. Turn on the motor 14 to drive the rotating blade 15 to rotate, so that the material in the material bin 1 is fully mixed. Turn off the motor 14, shorten the shaft telescopic rod 6 and lift the rotating blade 15 to the top of the material bin 1.

[0050] 3. Adjust the length of the conductive wire 12 in the material bin 1 through the telescopic button 18 so that the electrode 13 enters the material, turn on the power supply 7 and adjust it to a suitable voltage and current to electrolyze the material, and observe the electrolysis condition in the material bin 1 through the weighing instrument 10;

[0051] 4. After the electrolysis is completed, turn off the power supply 7, open the screw structure 16, take out the electrode 13 to collect mercury, take out the electrolyte for solid-liquid separation to obtain activated carbon, and recover the molten salt.

[0052] It can be seen from the above description that in the device for molten salt electrolysis regeneration and mercury recovery of waste mercuric chloride catalyst of the present invention, the height of the stirring mechanism is adjustable. After the stirring is completed, the stirring mechanism can be raised to separate from the material to avoid interference with the material in the material bin 1. The retractable electrolysis mechanism can meet the different heights of the material in the material bin 1. It has strong applicability and is easy to operate. It can realize the simultaneous mercury recovery and activated carbon regeneration of non-mercury chloride catalyst with high efficiency.

[0053] In a preferred embodiment, the sealing structure 3 of the present invention can improve the sealing performance of the material bin 1 and effectively prevent material leakage. After the electrolysis of the material in the material bin 1 is completed, the screw structure 16 can be opened to take out the material for separation of the activated activated carbon and the molten salt. The operation is simple and convenient; the weighing meter 10 can determine whether mercury is electrolyzed on the electrode 13 by the change in weight, and observe the progress of the electrolysis reaction; the heating mechanism 17 adopts electromagnetic heating with high thermal efficiency, so that the heat can effectively heat the molten salt and shorten the experimental cycle.

[0054] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A device for regenerating spent mercuric chloride catalyst by molten salt electrolysis and recovering mercury, characterized in that: The device comprises a material bin (1), wherein a height-adjustable stirring mechanism is provided at the top of an inner cavity of the material bin (1), and a heating mechanism (17) and a retractable electrolysis mechanism are also provided inside the material bin (1); a side wall of the material bin (1) is detachably connected to a main body of the material bin (1) via a screw structure (16), and a feeding room (2) and a conveying pipe (5) are provided at the top of the material bin (1) in sequence, and the material bin (1) and the feeding room (2) are both connected to the conveying pipe (5).

2. The device according to claim 1, characterized in that A sealing structure (3) is provided at the feed inlet of the feed room (2).

3. The device according to claim 1, characterized in that The stirring mechanism comprises a motor (14) located outside the feeding room (2), a shaft (4) located inside the feeding pipe (5), a shaft telescopic rod (6) sleeved outside the shaft (4), and a rotating blade (15) located at the bottom of the shaft telescopic rod (6).

4. The device according to any one of claims 1 to 3, characterized in that The heating mechanism (17) is located at the bottom of the inner cavity of the material bin (1), and comprises a heating cavity, a sleeve (23) located in the heating cavity, a metal tube (24) located in the sleeve (23), and an electromagnetic coil (22) wound around the metal tube (24), and a heat dissipation metal rod (21) is provided outside the heating cavity.

5. The device according to any one of claims 1 to 3, characterized in that The electrolysis mechanism comprises an electrode (13) located in the material bin (1), an electric conductive wire (12) connected to the electrode (13), a telescopic structure (9) for controlling the length of the electric conductive wire (12), and a power source (7) connected to the electric conductive wire (12).

6. The device according to claim 5, characterized in that A weighing instrument (10) is provided on the conductive wire (12) connected to the cathode of the electrode (13), and the weighing instrument (10) is located outside the material bin (1).

7. The device according to claim 5, characterized in that The telescopic structure (9) comprises an adjustment chamber and a control circuit (20) installed in the side wall of the adjustment chamber, the conductive wire (12) is inserted into the adjustment chamber, the portion of the conductive wire (12) located in the adjustment chamber is spiral-shaped, a mechanical rod (19) is provided in the adjustment chamber, a telescopic button (18) is provided on the outside of the adjustment chamber, and the mechanical rods (19) are distributed on both sides of the conductive wire (12).

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