Continuous device for producing ferrous oxalate through one-step method

Abstract

The utility model belongs to the technical field of ferrous oxalate production, and particularly relates to a continuous device for producing ferrous oxalate by a one-step method, which comprises a reaction device, a feeding device and a solid-liquid separation circulating device, the continuous device can realize continuous feeding and discharging and recycling of separated liquid, so that the production efficiency of ferrous oxalate is improved, and waste liquid is recycled while the yield is ensured.

Description

Technical Field

[0001] The utility model belongs to the technical field of ferrous oxalate production, and particularly relates to a continuous device for producing ferrous oxalate by a one-step method. Background Technique

[0002] Currently, most of the processes for preparing ferrous oxalate are synthesized by the reaction of oxalic acid and ferrous sulfate. In China, industrial-grade ferrous sulfate products are usually obtained as by-products of titanium dioxide production, which contain relatively high levels of heavy metals such as Zn, Mg, Mn, Ni, and S content. The prepared products do not meet the product indicators of battery-grade ferrous oxalate. Ferrous oxalate products that meet the indicators cannot be obtained even through water washing and impurity removal agents. Moreover, there has been no technological breakthrough in the purification of ferrous sulfate in China. Obtaining ferrous sulfate products that meet the indicators has a high cost and low output, and cannot meet the large-scale preparation of ferrous oxalate.

[0003] At present, the ferrous oxalate synthesis devices are all prepared in batches in different sections. The patent "A continuous reaction device for producing lithium manganese iron composite salt (CN218189577U)" designs a continuous reaction device for producing lithium manganese iron composite salt. The device is provided with a reaction tank, a ferrous powder bin, and a pump body, and can continuously discharge the reacted ferrous sulfate reaction solution from the reaction tank. However, this device does not consider all process links, the investment cost of batch preparation equipment is large, and the waste liquid cannot be fully recycled.

[0004] At present, there is an urgent need to develop a ferrous oxalate synthesis device that directly prepares ferrous oxalate by recycling acidic waste liquid as raw material liquid with iron powder and oxalic acid, realizes continuous production, and fully recycles the waste liquid, thereby realizing the continuous production of battery-grade ferrous oxalate, and the product has low cost, continuous production, and low heavy metal impurity content. Summary of the Invention

[0005] The utility model provides a continuous device for producing ferrous oxalate by a one-step method, which solves the above-mentioned technical problems, realizes the process flow of producing ferrous oxalate by a one-step method, and at the same time is a device for recycling the liquid separated from the product.

[0006] The solution of the utility model to the above technical problems is as follows:

[0007] A continuous device for producing ferrous oxalate by a one-step method, characterized in that it includes a reaction device, a feeding device, and a solid-liquid separation and recycling device. The feeding device is arranged above the reaction device, and the solid-liquid separation and recycling device is arranged below the reaction device. The reaction device is connected to the feeding device and the solid-liquid separation and recycling device through pipelines, and the solid-liquid separation and recycling device can circulate the reaction solution in the reaction device.

[0008] Further, the reaction device includes a reaction kettle. A temperature measuring port, a hydrogen discharge port, an iron powder feed port, and an oxalic acid feed port are provided at the top of the reaction kettle. Both the iron powder feed port and the oxalic acid feed port are connected to a feeding device through pipelines; a motor driving device is provided at the top of the reaction kettle and is connected to an internal stirring paddle. The motor driving device is connected to the stirring paddle through a stirring shaft. A liquid feed port is provided at the upper part of the side of the reaction kettle, and a product discharge port is provided at the lower part of the side of the reaction kettle. The product discharge port is connected to a solid-liquid separation and recycling device through a pipeline; a nitrogen inlet is provided at the bottom of the reaction kettle, and a liquid level gauge is provided on the side of the reaction kettle; the nitrogen inlet is connected to a nitrogen pipeline.

[0009] Further, the feeding device includes an iron powder bin, an oxalic acid bin, and a storage tank. The bottom of the iron powder bin is connected to the reaction kettle through an iron powder feed pipe. The bottom of the oxalic acid bin is connected to the reaction kettle through an oxalic acid feed pipe. The storage tank is communicated with a circulation pipeline through a liquid supplement pipe, and the circulation pipeline is communicated with the reaction kettle. A liquid level regulating valve is provided on the liquid supplement pipe, and a liquid level indicating and controlling device is provided on the liquid level gauge.

[0010] Further, the solid-liquid separation and recycling device includes a centrifuge and a circulation pump. The separator inlet at the top of the centrifuge is connected to the reaction kettle through a pipeline. The liquid outlet provided at the bottom side of the centrifuge is connected to the circulation pump through a pipeline. The outlet of the circulation pump is connected to the upper part of the reaction kettle through a circulation pipeline. A solid taking port is provided at the bottom side of the centrifuge.

[0011] Further, the reaction kettle is an open reaction kettle, and a jacket is provided on the kettle body of the reaction kettle. A jacket inlet and a jacket outlet are provided on the jacket.

[0012] Further, an acid-resistant non-magnetic coating made of polytetrafluoroethylene or polypropylene is provided on the inner wall of the reaction kettle.

[0013] Further, a metering discharger, a one-way valve, and a feed hose are sequentially provided on the iron powder feed pipe and the oxalic acid feed pipe along the material flow direction. A blanking chute is provided at the lower part of the metering discharger.

[0014] Further, the feed hose is a wear-resistant steel wire hose made of PU or TPU transparent material. Further, the liquid level regulating valve is connected to the liquid level indicating and controlling device.

[0015] Compared with the prior art, the beneficial effects of the present utility model are as follows: The feeding device, the reaction device and the solid-liquid separation and recycling device are connected through the upper, middle and lower regions. The raw materials in the upper feeding device can enter the reaction kettle in the middle reaction device by gravity to participate in the reaction, reducing power consumption and saving costs. Compared with the process of preparing ferrous oxalate with ferrous sulfate, only iron powder is introduced during the reaction process, and no other heavy metal impurities participate in the reaction. Continuous feeding and continuous discharging can be controlled. The product solution with ferrous oxalate precipitate is centrifuged by the centrifugal separator in the lower centrifugal separation device, and the waste acid solution is pumped back into the reaction kettle through the circulation pump to continue participating in the reaction for recycling, solving the problem of treating acidic waste liquid in the preparation of ferrous oxalate and reducing the equipment investment cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic structural diagram of the present utility model;

[0017] In the figure, 1. iron powder silo; 2. metering discharger a; 3. check valve a; 4. feed hose a; 5. oxalic acid silo; 6. metering discharger b; 7. check valve b; 8. feed hose b; 9. reaction kettle; 10. centrifuge; 11. circulation pump; 12. storage tank; 901. jacket; 902. nitrogen pipe; 903. motor drive device; 1101. circulation pipeline; 1201. liquid level regulating valve; 1202. liquid level indicating and controlling device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] Example 1

[0019] Referring to Figure 1 as shown, the present utility model provides a continuous device for one-step production of ferrous oxalate, including a reaction device, a feeding device and a solid-liquid separation and recycling device. The feeding device is arranged above the reaction device, and the solid-liquid separation and recycling device is arranged below the reaction device. The reaction device is connected to the feeding device and the solid-liquid separation and recycling device through pipelines, and the solid-liquid separation and recycling device can circulate the reaction liquid in the reaction device.

[0020] The reaction device includes a reaction kettle 9. A temperature measurement port, a hydrogen discharge port, an iron powder feed port, and an oxalic acid feed port are arranged at the top of the reaction kettle 9. Both the iron powder feed port and the oxalic acid feed port are connected to a feeding device through pipelines; a motor driving device 903 is arranged at the top of the reaction kettle 9 and is connected to an internal stirring paddle. The motor driving device 903 is connected to the stirring paddle through a stirring shaft. A liquid feed port is arranged at the upper part of the side of the reaction kettle 9, and a product discharge port is arranged at the lower part of the side of the reaction kettle 9. The product discharge port is connected to a solid-liquid separation and circulation device through a pipeline; a nitrogen gas inlet is arranged at the bottom of the reaction kettle 9, and a liquid level gauge is arranged on the side of the reaction kettle 9; the nitrogen gas inlet is connected to a nitrogen gas pipe 902. The reaction kettle 9 is an open reaction kettle, and a jacket 901 is arranged on the kettle body of the reaction kettle 9. A jacket inlet and a jacket outlet are arranged on the jacket 901. An acid-resistant and non-magnetic coating made of polytetrafluoroethylene is arranged on the inner wall of the reaction kettle 9. The open reaction kettle facilitates the disassembly and replacement of the internal components of the reaction kettle and the cleaning of the residues inside the reaction kettle. The setting of the jacket can heat the reaction kettle, thereby ensuring the reaction temperature inside the kettle and the reaction yield. The inner wall of the reaction kettle uses an acid-resistant and non-magnetic material coating to prevent the inner wall of the reaction kettle from being corroded by the acidic solution. The use of a non-magnetic material prevents the iron powder from sticking to the wall and thus slows down the reaction rate.

[0021] The feeding device includes an iron powder silo 1, an oxalic acid silo 5, and a storage tank 12. The bottom of the iron powder silo 1 is connected to the reaction kettle 9 through an iron powder feed pipe. The bottom of the oxalic acid silo 5 is connected to the reaction kettle 9 through an oxalic acid feed pipe. The storage tank 12 is communicated with the circulation pipeline 1101 through a liquid supplement pipe, and the circulation pipeline 1101 is communicated with the reaction kettle 9. A liquid level regulating valve 1201 is arranged on the liquid supplement pipe, and a liquid level indicating and controlling device 1202 is arranged on the liquid level gauge. A quantitative discharger a2, a one-way valve a3, and a feed hose a4 are sequentially arranged on the iron powder feed pipe along the material flow direction. A quantitative discharger b6, a one-way valve b7, and a feed hose b8 are sequentially arranged on the oxalic acid feed pipe along the material flow direction. Discharge chutes are arranged at the lower parts of the quantitative discharger a2 and the quantitative discharger b6. Both the feed hose a4 and the feed hose b8 are wear-resistant steel wire hoses made of PU transparent material. The liquid level regulating valve 1201 is connected to the liquid level indicating and controlling device 1202. The quantitative discharger is provided with a discharge chute, and equal-volume notches are designed according to the material ratio to discharge the materials in the iron powder silo and the oxalic acid silo and quantitatively, continuously, and evenly feed them into the reaction kettle for reaction. Since heating is required during the reaction and gas is generated, a one-way valve is set to control the one-way entry of materials into the reaction kettle, and the pipeline is closed when there is no feeding to prevent the gas in the reaction kettle from flowing back into the pipeline and the silo, reducing the problems of iron powder oxidation and solid oxalic acid caking. The PU is polyurethane, and its full name is polycarbamate. Since solid oxalic acid is prone to caking in the air and then causes pipeline blockage, a transparent hose is provided. When the raw materials are fed from above, the self-gravity of the raw materials can make the pipeline shake, causing the caked objects attached to the pipeline wall to fall off, ensuring continuous feeding. Also, the material state can be accurately and quickly observed during the feeding process. The liquid level indicating and controlling device controls the automatic adjustment of the opening of the liquid level regulating valve. When feeding for the first time during the reaction or when the inside of the reaction kettle is lower than the set liquid level, the opening of the liquid level regulating valve conveys the liquid in the storage tank to the reaction kettle through the liquid supplement pipe to ensure continuous reaction.

[0022] The solid-liquid separation and circulation device includes a centrifuge 10 and a circulation pump 11. The separator inlet at the top of the centrifuge 10 is connected to the reaction kettle 9 through a pipeline. The liquid outlet arranged on the side of the bottom of the centrifuge 10 is connected to the circulation pump 11 through a pipeline. The outlet of the circulation pump 11 is connected to the upper part of the reaction kettle through the circulation pipeline 1101. A solid material taking port is arranged on the side of the bottom of the centrifuge 10. Ensure that the acidic liquid participating in the reaction is completely recycled, there is no waste liquid discharge during the production process, and the taken solid materials are sent to the subsequent process section for treatment.

[0023] Another difference between the other embodiment and the first embodiment is that: an acid-resistant and non-magnetic coating made of polypropylene is arranged on the inner wall of the reaction kettle 9. The feed hose is a wear-resistant steel wire hose made of TPU transparent material, and TPU is the abbreviation of thermoplastic polyurethane elastomer.

[0024] Working principle of the utility model: The feeding device, the reaction device and the solid-liquid separation and recycling device are connected through three upper, middle and lower regions, reducing power consumption and saving costs. Compared with the process of preparing ferrous oxalate from ferrous sulfate, only iron powder is introduced during the reaction process, and no other heavy metal impurities participate in the reaction. Continuous feeding and continuous discharging can be controlled. The product solution with ferrous oxalate precipitate is centrifuged by the centrifuge in the lower centrifugal separation device, and the waste acid solution is pumped back into the reaction kettle through the circulation pump to continue participating in the reaction and recycling, solving the problem of treating acidic waste liquid in the preparation of ferrous oxalate and reducing costs.

[0025] The operation process of the utility model is as follows:

[0026] As Figure 1 shown, when feeding for the first time in this embodiment, a low-concentration sulfuric acid solution is configured in the storage tank 12. When starting up for the first time or when the liquid level in the reaction kettle is low, the low-concentration sulfuric acid solution is added to the reaction kettle 9 through the liquid supplement pipe 904 to reach the control liquid level of the reaction kettle; the iron powder in the iron powder bin 1 is transported to the reaction kettle 9 through the quantitative discharger a2, and the stirring device is started; the solid oxalic acid in the oxalic acid bin 5 is added into the reaction kettle 9 through the quantitative discharger b6 according to the corresponding proportion. During this period, ferrous oxalate precipitate is continuously generated. After stirring and reacting for a certain time, the stirring device is turned off. After standing for a certain time, the stirring device is started again and stirred for a certain time, and then the reaction liquid is discharged to the centrifuge 10 for solid-liquid separation. The separated solid precipitate is taken out from the solid taking port, and the separated acidic liquid is circulated to the reaction kettle 9 through the circulation pump 11 to continue participating in the reaction, and no acidic waste liquid is discharged; when the liquid in the reaction kettle 9 is lower than the set liquid level, the sulfuric acid solution in the storage tank 12 is transported to the reaction kettle 9 to meet the liquid level required for the reaction of the reaction kettle. A jacket 901 is arranged outside the reaction kettle 9 to provide heat source for the inside of the reaction kettle 9.

Claims

1. A continuous device for producing ferrous oxalate in one step, characterized in that: The invention comprises a reaction device, a feeding device and a solid-liquid separation circulation device. The feeding device is arranged above the reaction device, and the solid-liquid separation circulation device is arranged below the reaction device. The reaction device is connected with the feeding device and the solid-liquid separation circulation device through pipelines. The solid-liquid separation circulation device can circulate the reaction liquid in the reaction device.

2. A continuous device for producing ferrous oxalate by one-step method according to claim 1, characterized in that: The reaction device comprises a reactor (9), wherein a temperature measuring port, a hydrogen outlet, an iron powder feed port and an oxalic acid feed port are arranged at the top of the reactor (9), and the iron powder feed port and the oxalic acid feed port are both connected to a feeding device via a pipeline; a motor transmission device (903) arranged at the top of the reactor (9) is connected to a stirring paddle via a stirring shaft; a liquid feed port is arranged at the upper part of the side of the reactor (9), and a product discharge port is arranged at the lower part of the side of the reactor (9), and the product discharge port is connected to a solid-liquid separation circulation device via a pipeline; a nitrogen inlet is arranged at the bottom of the reactor (9), and a liquid level gauge is arranged at the side of the reactor (9); and the nitrogen inlet is connected to a nitrogen pipe (902).

3. A continuous device for producing ferrous oxalate by one-step method according to claim 2, characterized in that: The feeding device comprises an iron powder silo (1), an oxalic acid silo (5), and a storage tank (12); the bottom of the iron powder silo (1) is connected to a reactor (9) via an iron powder feeding pipe; the bottom of the oxalic acid silo (5) is connected to a reactor (9) via an oxalic acid feeding pipe; the storage tank (12) is connected to a circulation pipeline (1101) via a liquid replenishing pipe; the circulation pipeline (1101) is connected to the reactor (9); a liquid level regulating valve (1201) is provided on the liquid replenishing pipe; and the liquid level meter is provided with a liquid level indicating control device (1202).

4. A continuous device for producing ferrous oxalate in one step according to claim 1, characterized in that: The solid-liquid separation circulation device comprises a centrifugal separator (10) and a circulation pump (11); a separator inlet at the top of the centrifugal separator (10) is connected to a reactor (9) via a pipeline; a liquid outlet arranged on the bottom side of the centrifugal separator (10) is connected to the circulation pump (11) via a pipeline; an outlet of the circulation pump (11) is connected to the upper part of the reactor via a circulation pipeline (1101); and a solid material taking port is arranged on the bottom side of the centrifugal separator (10).

5. A continuous device for producing ferrous oxalate by one-step method according to claim 2, characterized in that: The reactor (9) is an open reactor. The reactor body of the reactor (9) is provided with a jacket (901). The jacket (901) is provided with a jacket inlet and a jacket outlet.

6. A continuous device for producing ferrous oxalate in one step according to claim 2, characterized in that: The inner wall of the reaction kettle (9) is provided with an acid-resistant non-magnetic coating made of polytetrafluoroethylene or polypropylene.

7. A continuous device for producing ferrous oxalate in one step according to claim 3, characterized in that: A quantitative discharger, a one-way valve, and a feeding hose are sequentially arranged on the iron powder feeding pipe and the oxalic acid feeding pipe along the material flow direction, and a discharge trough is arranged at the lower part of the quantitative discharger.

8. A continuous device for producing ferrous oxalate in one step according to claim 7, characterized in that: The feed hose is a wear-resistant steel wire hose made of transparent PU or TPU material.

9. A continuous device for producing ferrous oxalate in one step according to claim 3, characterized in that: The liquid level regulating valve (1201) is connected to the liquid level indicating control device (1202).

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