System and method for preparing arsenic trioxide through continuous reduction

文档序号：1263509 发布日期：2020-08-25 浏览：27次中文

阅读说明：本技术 一种连续还原制取三氧化二砷的系统及其方法 (System and method for preparing arsenic trioxide through continuous reduction ) 是由朱国荣魏海彬吴锦龙刘亮秦美静王勇江洋杨松桦代君邓力能周维伟于 2020-04-14 设计创作，主要内容包括：本发明涉及三氧化二砷制备技术,尤其涉及一种连续还原制取三氧化二砷的系统及其方法。系统包括：多级还原结晶装置、冷却装置、控制装置和自动抽出装置；多级还原结晶装置的一端通过管路分别与还原性气源和含砷液的储槽连接,另一端与自动抽出装置连接,控制装置安装在管路上,冷却装置安装在多级还原结晶装置的最后一级的还原性气体的管路上。本发明的系统可连续进料,物料成份波动小,还原效果稳定,由于一次还原槽内初始砷浓度较低,还原产生的颗粒大,干燥包装效果好,三次罗茨风机出口安装了水冷却器,三次还原槽内的温度显著降低,三价砷在液相中的饱和度下降,还原效果提升,且可以实现自动化,实现无人值守,具有很好的推广和应用前景。(The invention relates to a preparation technology of arsenic trioxide, in particular to a system and a method for preparing arsenic trioxide by continuous reduction. The system comprises: the device comprises a multistage reduction crystallization device, a cooling device, a control device and an automatic extraction device; one end of the multistage reduction crystallization device is respectively connected with a reducing gas source and a storage tank containing arsenic liquid through pipelines, the other end of the multistage reduction crystallization device is connected with an automatic pumping device, a control device is installed on the pipelines, and a cooling device is installed on the pipeline of the last stage of reducing gas of the multistage reduction crystallization device. The system of the invention can continuously feed materials, has small material component fluctuation and stable reduction effect, has large particles generated by reduction due to lower initial arsenic concentration in the primary reduction tank, and good drying and packaging effects, and has the advantages that the outlet of the third Roots blower is provided with the water cooler, the temperature in the third reduction tank is obviously reduced, the saturation of trivalent arsenic in a liquid phase is reduced, the reduction effect is improved, the automation can be realized, the unattended operation is realized, and the popularization and application prospects are good.)

1. A system for preparing arsenic trioxide by continuous reduction is characterized in that: the device includes: the device comprises a multistage reduction crystallization device, a cooling device, a control device and an automatic extraction device;

the multistage reduction crystallization device is used for sucking the arsenic-containing liquid and performing multistage reduction treatment on the arsenic-containing liquid by utilizing reducing gas;

the cooling device is used for cooling the last stage of reducing gas and realizing cooling of liquid phase temperature so as to reduce the saturation degree of crystallization and increase the crystallization efficiency;

the control device is used for controlling the flow of the reducing gas and the flow of the arsenic-containing liquid;

the automatic extraction device is used for extracting the reduced suspension,

one end of the multistage reduction crystallization device is connected with a reducing gas source and a storage tank containing arsenic liquid through pipelines respectively, the other end of the multistage reduction crystallization device is connected with the automatic pumping device, the control device is installed on the pipelines, and the cooling device is installed on the pipeline of the reducing gas of the last stage of the multistage reduction crystallization device.

2. The system for preparing arsenic trioxide by continuous reduction according to claim 1, wherein:

the system also comprises a gas recovery device, wherein the gas recovery device is used for recovering and intensively treating the redundant reducing gas;

the gas recovery device comprises a recovery pipeline, a gas collection fan and a tail gas treatment device, wherein one end of the gas collection fan is connected with the multistage reduction crystallization device through the recovery pipeline, and the other end of the gas collection fan is connected with the tail gas treatment device.

3. The system for producing arsenic trioxide by continuous reduction according to claim 1 or 2, wherein: the multistage reduction crystallization apparatus includes: the device comprises a liquid supply pump, a primary reduction tank, a secondary reduction tank, a tertiary reduction tank, a primary Roots blower, a secondary Roots blower and a tertiary Roots blower;

the liquid supply pump is connected with one end of the primary reduction tank through a pipeline, one end of the bottom of the primary reduction tank is connected with one end of the bottom of the secondary reduction tank through a pipeline, and the other end of the bottom of the secondary reduction tank is connected with one end of the bottom of the tertiary reduction tank through a pipeline;

one end of the primary Roots blower is connected with the primary reduction groove through a pipeline, one end of the secondary Roots blower is connected with the secondary reduction groove through a pipeline, one end of the tertiary Roots blower is connected with the tertiary reduction groove through a pipeline, and the other ends of the primary Roots blower, the secondary Roots blower and the tertiary Roots blower are connected with a reducing gas source.

4. The system for preparing arsenic trioxide by continuous reduction according to claim 3, wherein: the cooling device is arranged on a pipeline between the third roots blower and the third reduction tank and is a water cooler.

5. The system for preparing arsenic trioxide by continuous reduction according to claim 4, wherein: the control device comprises a flow meter, a pneumatic regulating valve and a DSC control system;

the DSC control system is connected with the flow meter and the pneumatic regulating valve in a control way.

6. The system for preparing arsenic trioxide by continuous reduction according to claim 5, wherein: the automatic pumping device comprises a liquid level detection sensor, a desorption groove, a pumping pump and a desorption Roots blower;

wherein the bottom of the tertiary reduction tank is connected with the bottom of the desorption tank through a pipeline, the desorption tank is connected with a suction pump through a pipeline,

one end of the desorption Roots blower is connected with an air source, the other end of the desorption Roots blower is connected with the top of the desorption groove through a pipeline, and the extraction pump and the desorption Roots blower are both connected with the DSC control system.

7. The system for preparing arsenic trioxide by continuous reduction according to claim 6, wherein: stirring devices are arranged on the primary reduction tank, the secondary reduction tank, the tertiary reduction tank and the desorption tank;

liquid level detection sensors are arranged in the storage tank, the primary reduction tank, the secondary reduction tank, the tertiary reduction tank and the desorption tank;

and the stirring device and the liquid level detection sensor are both connected with a DSC control system.

8. A method for producing arsenic trioxide by continuous reduction using the system according to any one of claims 1 to 7, characterized in that the method comprises the following steps:

s1), starting a system, automatically adjusting the arsenic-containing liquid oxidized in the autoxidation procedure by a pneumatic adjusting valve according to a set value of a flowmeter, and sending the arsenic-containing liquid to a multi-stage reduction treatment device, wherein the multi-stage reduction treatment device performs multi-stage reduction treatment on the arsenic-containing liquid by using reducing gas;

s2) when the automatic extraction device detects that the liquid level of the arsenic trioxide suspension obtained after reduction treatment reaches 80% of the total volume, extracting the arsenic trioxide suspension, and stopping extracting when the total volume is low by 80%;

s3) conveying the extracted arsenic trioxide suspension to a centrifugal separation process to produce arsenic trioxide particles which meet the national first-grade product standard.

9. The method as claimed in claim 8, wherein the arsenic-containing liquid in S1) is pentavalent arsenic in the form of arsenic acid and has a concentration of 30-150 g/l.

10. The method as claimed in claim 8, wherein the reducing gas in S2) is SO with a concentration of 8-15%₂Flue gases or SO₂Gas, said SO₂The flue gas is purified from smelting flue gas and contains SO₂Flue gas.

Technical Field

The invention relates to a preparation technology of arsenic trioxide, in particular to a method adopting SO₂A system and a method for preparing arsenic trioxide by continuous reduction of a high-arsenic reduction liquid wet method.

Background

The existing wet method for producing arsenic trioxide generally adopts liquid SO₂Reduction or reduction by using smelting purification flue gas, but single-groove intermittent reduction is mostly adopted, the operation amount is large, and full-automatic control cannot be realized; meanwhile, the liquid phase components in different batches fluctuate greatly, so that the technological parameters are difficult to adjust, and the reduction cannot achieve the expected effect; because the liquid phase at the initial stage of reduction has high arsenic concentration, the crystallization driving force is large during reduction, the crystallization speed is high, and the crystallization particles are fine, thereby being not beneficial to the drying and packaging at the later stage.

Disclosure of Invention

The invention provides a method for producing arsenic trioxide by continuous reduction, which provides a reduction method for preparing arsenic trioxide by a wet method, can greatly improve the automation degree, simultaneously has small fluctuation of material components and stable reduction effect because of continuous feeding, and has large particles produced by reduction and good drying and packaging effects because the initial arsenic concentration in a primary reduction tank is lower. Because the outlet of the third Roots blower is provided with the water cooler, the temperature in the third reduction tank is obviously reduced, the saturation of the trivalent arsenic in the liquid phase is reduced, and the reduction effect is improved.

In order to solve the technical problems, the technical scheme of the invention is as follows: a system for preparing arsenic trioxide by continuous reduction comprises: the device comprises a multistage reduction crystallization device, a cooling device, a control device and an automatic extraction device;

the control device is used for controlling the flow of the reducing gas and the flow of the arsenic-containing liquid;

the automatic extraction device is used for extracting the residual liquid after reduction,

Further, the device also comprises a gas recovery device, wherein the gas recovery device is used for recovering and intensively treating the redundant reducing gas;

Further, the multistage reduction crystallization apparatus includes: a liquid supply pump, a primary reduction tank, a secondary reduction tank, a tertiary reduction tank, a primary Roots blower, a secondary Roots blower and a tertiary Roots blower,

The liquid supply pump is connected with one end of the primary reduction tank through a pipeline, one end of the bottom of the primary reduction tank is connected with one end of the bottom of the secondary reduction tank through a pipeline, and the other end of the bottom of the secondary reduction tank is connected with one end of the bottom of the tertiary reduction tank through a pipeline;

Further, the cooling device is arranged on a pipeline between the third roots blower and the third reduction tank, and the cooling device is a water cooler.

Further, the control device comprises a flow meter, a pneumatic regulating valve and a DCS system;

the DSC control system is connected with the flow meter and the pneumatic regulating valve in a control way.

Further, the automatic pumping device comprises a desorption groove, a pumping pump and a desorption Roots blower;

wherein the bottom of the tertiary reduction tank is connected with the bottom of the desorption tank through a pipeline, the desorption tank is connected with a suction pump through a pipeline,

one end of the desorption Roots blower is connected with an air source, and the other end of the desorption Roots blower is connected with the top of the desorption groove through a pipeline.

Further, stirring devices are arranged on the primary reduction tank, the secondary reduction tank, the tertiary reduction tank and the desorption tank;

liquid level detection sensors are arranged in the storage tank, the primary reduction tank, the secondary reduction tank, the tertiary reduction tank and the desorption tank;

and the stirring device and the liquid level detection sensor are both connected with a DSC control system.

The invention also aims to provide a method for preparing arsenic trioxide by continuous reduction by adopting the system, which comprises the following steps:

s3) delivering the extracted arsenic trioxide suspension to a centrifugal separation process to produce arsenic trioxide particles which meet the national first-grade product standard (GB 26721-2011).

Namely, the whiteness of the arsenic trioxide is more than or equal to 60 percent, the arsenic trioxide is white or grey white particles or powder, the content of the arsenic trioxide is not less than 99.5 percent, Cu in the impurities is less than 0.005 percent, Zn is less than 0.001 percent, Fe is less than 0.002 percent, Pb is less than 0.001 percent, and Bi is less than 0.001 percent.

Further, the arsenic-containing liquid in S1) is pentavalent arsenic in the form of arsenic acid, and the concentration of arsenic acid is 30-150 g/l.

Further, the reducing gas in the S2) is SO with the concentration of 8-15%₂Flue gases or SO₂Gas, said SO₂The flue gas is purified from smelting flue gas and contains SO₂Flue gas.

The invention has the beneficial effects that: by adopting the technical scheme, the invention not only can ensure the reduction preparation of arsenic in the process of preparing arsenic trioxide by a wet method, but also can ensure the coarse particles of the prepared arsenic trioxide, is beneficial to drying and packaging, can mainly realize automation and unattended operation, and has good popularization and application prospects.

Description of the drawings:

FIG. 1 is a schematic structural diagram of a system for preparing arsenic trioxide by continuous reduction according to the present invention.

In the figure:

1. a storage tank; 2. a primary reduction tank; 3. a secondary reduction tank; 4. a third reduction tank; 5. a desorption groove; 6. a liquid supply pump; 7. a pump for pumping out; 8. a Roots blower; 9. a secondary Roots blower; 10. a third Roots blower; 11. a desorption Roots blower; 12. a gas collection fan; 13. a water cooler; 14. a flow meter; 15. a pneumatic regulating valve; a DSC control system; 17, a stirring device; 18. a tail gas treatment device; 19. a recovery pipeline; 20. a liquid level detection sensor.

The specific implementation mode is as follows:

the technical solution of the present invention is further explained with reference to the accompanying drawings and specific embodiments.

As shown in FIG. 1, the present invention provides a system for preparing arsenic trioxide by continuous reduction, which comprises: a multistage reduction crystallization device, a cooling device 13, a control device and an automatic extraction device;

the cooling device 13 is used for cooling the last stage of reducing gas and realizing cooling of the liquid phase temperature so as to reduce the saturation degree of crystallization and increase the crystallization efficiency;

the control device is used for controlling the flow of the reducing gas and the flow of the arsenic-containing liquid;

the automatic extraction device is used for extracting the residual liquid after reduction,

The device also comprises a gas recovery device, wherein the gas recovery device is used for recovering and intensively treating the redundant reducing gas;

the gas recovery device comprises a recovery pipeline 19, a gas collection fan 12 and a tail gas treatment device 18, wherein one end of the gas collection fan 12 is connected with the multistage reduction crystallization device through the recovery pipeline 19, and the other end of the gas collection fan is connected with the tail gas treatment device 18.

The arsenic trioxide crystallization device comprises: a liquid supply pump 6, a primary reduction tank 2, a secondary reduction tank 3, a tertiary reduction tank 4, a primary Roots blower 8, a secondary Roots blower 9, a tertiary Roots blower 10,

The liquid supply pump is connected with one end of the primary reduction tank 2 through a pipeline 6, one end of the bottom of the primary reduction tank 3 is connected with one end of the bottom of the secondary reduction tank 3 through a pipeline, and the other end of the bottom of the secondary reduction tank 3 is connected with one end of the bottom of the tertiary reduction tank 4 through a pipeline;

one end of the primary roots blower 8 is connected with the primary reduction groove 2 through a pipeline, one end of the secondary roots blower 9 is connected with the secondary reduction groove 3 through a pipeline, one end of the tertiary roots blower 10 is connected with the tertiary reduction groove 4 through a pipeline, and the other ends of the primary roots blower 2, the secondary roots blower 3 and the tertiary roots blower 4 are all connected with a reducing gas source.

The cooling device 13 is arranged on a pipeline between the tertiary roots blower 10 and the tertiary reduction tank 4, and the cooling device 13 is a water cooler.

The control device comprises a flow meter 14, a pneumatic regulating valve 15 and a DSC control system 16;

wherein, the flowmeter 14 and the pneumatic control valve 15 are arranged on a pipeline between the liquid supply pump and the primary reduction tank, and the DSC control system 16 is in control connection with the flowmeter 14 and the pneumatic control valve 15.

The automatic pumping device comprises a desorption groove 5, a pumping pump 7 and a desorption Roots blower 11;

wherein the bottom of the tertiary reduction tank is connected with the bottom of the desorption tank 5 through a pipeline, the desorption tank 5 is connected with the extraction pump 7 through a pipeline,

one end of the desorption Roots blower 11 is connected with an air source, and the other end of the desorption Roots blower is connected with the top of the desorption groove 5 through a pipeline.

The primary reduction tank 2, the secondary reduction tank 3 and the tertiary reduction tank 4 are respectively provided with a stirring device 17;

liquid level detection sensors 20 for detecting liquid levels are arranged in the storage tank 1, the primary reduction tank 2, the secondary reduction tank 3, the tertiary reduction tank 4 and the desorption tank 5;

the stirring device 17 and the liquid level detection sensor 20 are both connected with a DSC control system.

A method for preparing arsenic trioxide by continuous reduction by adopting the system for preparing arsenic trioxide by continuous reduction,

s3) conveying the extracted arsenic trioxide suspension to a centrifugal separation process to produce arsenic trioxide particles which meet the national first-grade product standard.

The method adopts three-stage continuous reduction (the number of reduction tanks can be reduced or increased according to the size of the liquid supply amount and the arsenic concentration of the liquid phase).

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System and method for preparing arsenic trioxide through continuous reduction

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