A method and device for detecting and ensuring the oxidation-reduction potential of waste acid

Abstract

The application discloses a kind of waste acid oxidation-reduction potential detection guarantee method and device, waste acid from sulfidation reactor is respectively transported to cyclone and desorption tower by waste acid delivery pump through pipeline;Waste acid transported to cyclone enters cyclone along tangent direction, then by the outlet at the top of cyclone spirally rises into ORP flow cell;Low solid content waste acid contacts detection probe, and rotating scouring detection probe slows down solid aggregation on probe coating, then from the third waste acid outlet of side wall flows into desorption tower;Waste acid from cyclone and ORP flow cell converges after waste acid in desorption tower, and is transported to thickener processing by waste acid supply pump.The application process is simple, can effectively improve process operating environment, has good environmental protection benefit, ensures enterprise safety production, solves the detection precision problem of waste acid oxidation-reduction potential detection probe.

Description

TECHNICAL FIELD

[0001] The present application relates to waste acid detection and treatment technology, in particular to a waste acid oxidation-reduction potential detection guarantee method and device. BACKGROUND

[0002] China's non-ferrous smelting industry has developed rapidly, and a large amount of waste acid containing copper, arsenic and other ions is generated in the production process. Many scholars and related enterprises in China use sulfides to remove copper, arsenic and other ions from waste liquid.

[0003] The main arsenic removal process uses sodium sulfide, sodium sulfide, hydrogen sulfide and other sulfides as arsenic removal agents. The arsenic removal agent is first introduced into the sulfidation reactor to produce copper sulfide and arsenic sulfide precipitates with copper and arsenic ions in the waste acid. At the same time, a small amount of by-product hydrogen sulfide gas is dissolved in the solution. The waste acid leaving the sulfidation reactor is then sequentially passed through the thickener and filter press to separate the copper sulfide and arsenic sulfide precipitates from the waste acid solution, thereby removing copper and arsenic ions from the waste acid.

[0004] Oxidation-reduction potential (ORP) is used to reflect the macroscopic oxidation-reduction properties of all substances in the waste acid. The higher the oxidation-reduction potential, the stronger the oxidizing property, and the lower the oxidation-reduction potential, the stronger the reducing property. A positive potential indicates that the solution exhibits certain oxidizing properties, and a negative potential indicates that the solution exhibits certain reducing properties.

[0005] The existing waste acid arsenic removal process adjusts the proportion of sulfides and waste acid entering the sulfidation reaction by detecting the oxidation-reduction potential (ORP) of the waste acid leaving the sulfidation reactor. Oxidation-reduction potential (ORP) is an important control index for normal operation of the process, and the installation method and position of the oxidation-reduction potential meter directly affect the accuracy of the oxidation-reduction potential of the waste acid.

[0006] In the current mainstream process, the oxidation-reduction potential instrument is mainly installed on the overflow pipeline from the sulfidation reactor to the thickener. However, the flow rate of waste acid in the overflow pipeline is low, and it is mixed with solid such as copper sulfide and arsenic sulfide. The oxidation-reduction potential instrument detection probe is immersed in waste acid for a long time, and the phenomenon of low accuracy of oxidation-reduction potential detection value caused by solid aggregation covering on the probe is common, which further affects the entire process operation, and finally leads to incomplete removal of copper and arsenic ions in waste acid or excessive addition of arsenic removal agent. In actual production, in order to solve this problem, the process operator needs to take out the oxidation-reduction potential instrument detection probe and wash it with clean water once a week. At the same time, due to the dissolution of a small amount of by-produced hydrogen sulfide gas in the waste acid, the overflow of hydrogen sulfide gas is common during the disassembly and cleaning of the oxidation-reduction potential instrument detection probe. The overflow of hydrogen sulfide gas, as a toxic gas, poses a great safety threat to the health of process operators. In addition, a small amount of hydrogen sulfide gas is also overflowed during the pressure filtration of waste acid, with an average overflow amount of 200 mg / h, causing the operation environment of the pressure filter house to be unfriendly. SUMMARY

[0007] Based on the above situation, the present application provides a waste acid oxidation-reduction potential detection guarantee method and device based on precise environmental protection, in order to solve the problem of solid covering on the oxidation-reduction potential instrument detection probe, avoid frequent disassembly of the detection probe, and the resulting problem of unfriendly environment in the pressure filter house.

[0008] The purpose of the present application is achieved as follows. A waste acid oxidation-reduction potential detection guarantee method has the following process:

[0009] 1) The waste acid from the sulfidation reactor is transported to the cyclone and the desorption tower through the pipeline by the waste acid conveying pump respectively;

[0010] 2) The waste acid transported to the cyclone enters the cyclone along the tangent direction, and preliminary liquid-solid separation is carried out in the cyclone. The inlet waste acid is separated into two materials of high solid content waste acid and low solid content waste acid. The high solid content waste acid moves downward along the axial direction under the action of the cyclone field, then moves outward along the radial direction, reaches the conical section, and then moves downward along the inner wall of the cyclone to the first waste acid outlet at the bottom; the low solid content waste acid moves towards the central axis, and an inner vortex moving upward is formed at the center of the axis, and then rises spirally from the outlet at the top of the cyclone to the ORP flow cell;

[0011] 3) The low solid content waste acid contacts with the detection probe, and the rotation of the detection probe reduces the aggregation and covering of solid on the probe, and then flows into the desorption tower from the third waste acid outlet of the side wall;

[0012] 4) A cut-off valve is arranged on the first waste acid inlet pipeline of the hydrocyclone, which is automatically closed every certain time, while a switch valve on the pipeline of the sidewall flushing water outlet of the ORP flow cell is opened, so as to flush the detection probe and remove the solid gathered around the detection probe.

[0013] A waste acid oxidation-reduction potential detection guarantee method further comprises the following steps:

[0014] 1) The waste acid from the waste acid delivery pump enters the upper part of the desorption tower through the spray inlet, and is in countercurrent contact with the air entering the gas collector through the air inlet on the sidewall of the desorption tower, so as to remove the hydrogen sulfide gas in the waste acid; the top outlet of the desorption tower is connected to the harm-removing tower through negative pressure suction, so as to send the desorbed hydrogen sulfide-containing gas to the harm-removing tower for harmless treatment.

[0015] 2) The waste acid from the hydrocyclone and the ORP flow cell is combined with the waste acid in the desorption tower, and then is delivered to the thickener for treatment by the waste acid supply pump.

[0016] Preferably, the certain time is 2-6 h.

[0017] Preferably, the ORP flow cell flushing water pressure is 0.1-0.3 MPa.

[0018] Preferably, the gas pressure in the desorption tower is -4.0 to -1.0 kPa, the liquid-gas ratio is 5-10 x 10 -3 m 3 / Nm 3 , and the liquid spray density is 20-30 m 3 / (m 2 ·h).

[0019] A device based on a waste acid oxidation-reduction potential detection guarantee method comprises a hydrocyclone and a desorption tower, wherein the outlet at the top of the hydrocyclone is connected to the bottom of an ORP flow cell.

[0020] A first waste acid inlet arranged on the upper sidewall of the hydrocyclone is connected to a waste acid delivery pump through a pipeline, and a cut-off valve is arranged on the pipeline; a first waste acid outlet at the bottom of the lower section of the hydrocyclone is connected to a second waste acid inlet at the bottom of the desorption tower through a pipeline.

[0021] A detection probe is arranged in the ORP flow cell, a third waste acid outlet arranged on one sidewall is connected to the second waste acid inlet at the bottom of the desorption tower through a pipeline, and a flushing water pipeline is connected to a flushing water outlet arranged on the other sidewall, and a switch valve is arranged on the flushing water pipeline.

[0022] Further, a gas collector is arranged on the side of the ORP flow cell, for collecting the air near the ORP flow cell.

[0023] The lower part of one side wall of the desorption tower is provided with an air inlet communicated with the gas collecting hood through a flue gas pipeline, and the upper part of the other side wall is provided with a single-layer or multi-layer spraying inlet and connected with a waste acid delivery pump through a pipeline;

[0024] The second waste acid outlet arranged at one side of the lower part of the desorption tower is communicated with a waste acid supply pump;

[0025] The top outlet of the desorption tower is communicated with a decontamination tower through a pipeline.

[0026] The ORP flow cell in the application is installed at the outlet of the cyclone, and the low solid content waste acid rotates and washes the detection probe in the ORP flow cell, which can effectively slow down the aggregation and coating of solids on the detection probe, achieve cleaning once every two months, and greatly reduce the frequency of manual disassembly and cleaning of the detection probe. The detection probe is regularly washed by the side wall flushing water pipe of the ORP flow cell, which effectively removes the accumulated solids on the detection probe and ensures the detection accuracy. The negative pressure gas collecting hood is arranged on the side of the ORP flow cell, which can collect the overflow hydrogen sulfide gas in time, so that the average overflow amount of hydrogen sulfide is 80 mg / h, and the operation environment near the ORP flow cell is effectively improved. The desorption tower uses the gas collected by the gas collecting hood for hydrogen sulfide removal treatment of waste acid, which can greatly reduce the overflow amount of hydrogen sulfide in the waste acid during the pressure filtration process, and further improve the operation environment of the waste acid pressure filter room. The process of the application is simple, which can effectively improve the process operation environment, has good environmental protection benefit, ensures the safety production of enterprises, and solves the problem of affecting the detection accuracy of the oxidation-reduction potential detection probe of waste acid. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a structural schematic diagram of the application;

[0028] Figure 2 is a waste acid liquid flow direction schematic diagram of the cyclone 2 in the application;

[0029] In the figure: 1. waste acid delivery pump; 2. cyclone, 21. first waste acid inlet, 211. shut-off valve, 22. first waste acid outlet; 3. ORP flow cell, 31. detection probe, 32. third waste acid outlet, 33. flushing water port, 331. on-off valve; 4. gas collecting hood; 5. desorption tower, 51. spraying inlet, 52. air inlet, 53. second waste acid inlet, 54. second waste acid outlet, 55. top outlet; 6. waste acid supply pump. DETAILED DESCRIPTION

[0030] The application will be further described below in combination with the drawings and examples. Referring to Figure 1 and Figure 2The application discloses a kind of waste acid oxidation-reduction potential detection guarantee device, including a cyclone 2 and a desorption tower 5, the top outlet 55 of the cyclone 2 is connected with the bottom of ORP flow cell 3;First waste acid inlet 21 of cyclone 2 upper segment side wall is connected with waste acid delivery pump 1 by pipeline, and a cut-off valve 211 is installed on the pipeline;First waste acid outlet 22 of cyclone 2 lower segment bottom is connected with the second waste acid inlet 53 of the bottom of desorption tower 5 by pipeline;Detection probe 31 is arranged in ORP flow cell 3, and third waste acid outlet 32 is connected with the second waste acid inlet 53 of the bottom of desorption tower 5 by pipeline, and flushing water pipe is connected with flushing water port 33 arranged on the other side wall, and a switch valve 331 is installed on the flushing water pipe;Gas hood 4 is arranged on the side of ORP flow cell 3, for collecting air near ORP flow cell 3;Air inlet 52 is arranged on the lower part of one side wall of desorption tower 5 and is communicated with gas hood 4 by flue gas pipeline, because the decontamination tower is provided with a blower, negative pressure is formed in gas hood 4 by the blower, and the air containing hydrogen sulfide in the equipment system or environment is sent to the decontamination tower for harmless treatment. The top of desorption tower 5 is connected with the inlet of fan by pipeline, and the lower air inlet 52 of desorption tower 5 is connected with gas hood 4 by pipeline. Single-layer or multi-layer spray inlet 51 is arranged on the upper part of the other side wall and is connected with waste acid delivery pump 1 by pipeline;Second waste acid outlet 54 arranged on one side of the lower part of desorption tower 5 is communicated with waste acid supply pump 6;The top outlet 55 of desorption tower 5 is communicated with the decontamination tower by pipeline.

[0031] Embodiment 1:

[0032] In combination with a waste acid treatment project of a smelting plant, the waste acid oxidation-reduction potential detection guarantee device method based on precise environmental protection of an embodiment of the application includes the following steps:

[0033] 1) The waste acid from the sulfuration reactor is transported to cyclone 2 (made of glass fiber reinforced plastic, with a diameter of 0.6 m) and desorption tower 5 (made of glass fiber reinforced plastic, with a bottom diameter of 2.8 m and an upper diameter of 1.6 m) by waste acid delivery pump 1 (horizontal engineering plastic pump, with a flow rate of 44 m 3 / h and a lift of 30 m) through pipelines respectively, and the volume flow rate of the waste acid is 40 m 3 / h, and the solid content is about 8 g / L;

[0034] 2) the waste acid delivered to the cyclone 2 enters the cyclone 2 along a tangential direction, and preliminary liquid-solid separation is performed in the cyclone 2, the inlet waste acid is separated into high solid content waste acid and low solid content waste acid, wherein the high solid content waste acid simultaneously moves downward along an axial direction and moves outward along a radial direction under the action of a cyclone field, and reaches the conical section to move downward along the inner wall of the cyclone 2 to the first waste acid outlet 22 at the bottom to flow to the bottom of the desorption tower 5; the low solid content waste acid moves towards the central axis, and an inner vortex moving upward is formed at the center of the axis, and then spirally rises to the ORP flow cell 3 (as shown in Figure 2 ) from the outlet at the top of the cyclone 2;

[0035] 3) the low solid content waste acid contacts the detection probe 31, and the rotation scouring detection probe 31 slows down the aggregation and coating of solids on the probe, and then flows into the desorption tower 5 from the third waste acid outlet 32 of the side wall;

[0036] 4) the shut-off valve 211 on the first waste acid inlet 21 pipeline of the cyclone 2 is automatically closed every 6 hours, and the switch valve 331 on the side wall flushing water outlet 33 pipeline of the ORP flow cell 3 is opened at the same time, so as to flush the detection probe 31, the flushing water pressure is 0.15 MPa, and the solids aggregated around the detection probe 31 are removed;

[0037] 5) the waste acid from the waste acid delivery pump 1 enters the upper part of the desorption tower 5 through the spray inlet 51, and is in countercurrent contact with the air containing hydrogen sulfide gas collected by the gas collector 4 through the air inlet 52 of the side wall of the desorption tower 5, so as to remove the hydrogen sulfide gas in the waste acid; the top outlet 55 of the desorption tower 5 forms a negative pressure in the gas collector 4 through a blower, so as to suck the desorbed gas containing hydrogen sulfide to a harm-removing tower for harmless treatment; the gas pressure in the desorption tower 5 is-2 kPa, the liquid-gas ratio is 6x10 -3 m 3 / Nm 3 , and the liquid spray density is 20 m 3 / (m 2 ·h);

[0038] 6) the waste acid from the cyclone 2 and the ORP flow cell 3 is combined with the waste acid in the desorption tower 5, and then is delivered to a thickener for treatment by a waste acid supply pump 6.

[0039] Embodiment 2:

[0040] In combination with a waste acid treatment project of a smelting plant, another embodiment of the waste acid oxidation-reduction potential detection guarantee device method based on precise environmental protection includes the following steps:

[0041] 1) the waste acid from a sulfidation reactor is delivered to the waste acid delivery pump 1 (a horizontal engineering plastic pump, a flow rate is 68 m 3 / h, the head 30 m) are respectively transported to the cyclone 2 (glass fiber reinforced plastic, diameter 0.6 m) and the desorption tower 5 (glass fiber reinforced plastic, bottom diameter 3 m, upper diameter 1.8 m) through pipelines, and the volume flow of the waste acid is 60 m 3 / h, the solid content is about 12 g / L;

[0042] 2) The waste acid transported to the cyclone 2 enters the cyclone 2 along the tangential direction, and the preliminary liquid-solid separation is carried out in the cyclone 2. The inlet waste acid is separated into high solid content waste acid and low solid content waste acid. The high solid content waste acid moves downward along the axial direction and moves outward along the radial direction under the action of the cyclone field, and reaches the cone section to move downward along the inner wall of the cyclone 2 to the first waste acid outlet 22 at the bottom to flow to the bottom of the desorption tower 5. The low solid content waste acid moves towards the central axis, and forms an inner vortex moving upward at the center of the axis, and then spirally rises to the ORP flow cell 3 (as shown in Figure 2 ) from the outlet at the top of the cyclone 2.

[0043] 3) The low solid content waste acid contacts the detection probe 31, and the rotation scouring detection probe 31 slows down the solid accumulation on the probe, and then flows into the desorption tower 5 from the third waste acid outlet 32 of the side wall.

[0044] 4) The cut-off valve 211 on the pipeline of the first waste acid inlet 21 of the cyclone 2 is automatically closed every 2 h, and the switch valve 331 on the pipeline of the side wall flushing water outlet 33 of the ORP flow cell 3 is opened at the same time, so as to flush the detection probe 31, and the flushing water pressure is 0.2 MPa; the solid accumulated around the detection probe 31 is removed.

[0045] 5) The waste acid from the waste acid conveying pump 1 enters the upper part of the desorption tower 5 through the spray inlet 51, and is in countercurrent contact with the air containing hydrogen sulfide gas collected by the gas collecting hood 4 through the air inlet 52 of the side wall of the desorption tower 5, so as to remove the hydrogen sulfide gas in the waste acid; the desorbed gas containing hydrogen sulfide is sent to the harm removal tower for harmless treatment through the negative pressure suction of the top outlet 55 of the desorption tower 5; the gas pressure in the desorption tower 5 is-4 kPa, and the liquid-gas ratio is 8×10 -3 m 3 / Nm 3 , and the liquid spray density is 25 m 3 / (m 2 ·h).

[0046] 6) The waste acid from the cyclone 2 and the ORP flow cell 3 is combined with the waste acid in the desorption tower 5, and then is transported to the thickener for treatment by the waste acid supply pump 6.

[0047] Example 3:

[0048] With reference to the waste acid treatment project of a smelting plant, the application has another embodiment of a waste acid oxidation-reduction potential detection guarantee device method based on precise environmental protection, which comprises the following steps:

[0049] 1) The waste acid from the sulfidation reactor is transported by a waste acid delivery pump 1 (horizontal engineering plastic pump, flow rate 55 m 3 / h, head 30 m) to a cyclone 2 (glass fiber reinforced plastic, diameter 0.6 m) and a desorption tower 5 (glass fiber reinforced plastic, bottom diameter 2.5 m, upper diameter 1.5 m) through pipelines respectively, and the waste acid has a volume flow rate of 50 m 3 / h, and contains about 10 g / L of solid content;

[0050] 2) The waste acid transported to the cyclone 2 enters the cyclone 2 along the tangent direction, and preliminary liquid-solid separation is performed in the cyclone 2, the inlet waste acid is separated into high-solid-content waste acid and low-solid-content waste acid, the high-solid-content waste acid moves downward along the axial direction and moves outward along the radial direction under the action of the cyclone field, reaches the conical section, moves downward along the inner wall of the cyclone 2 to the bottom, and is discharged from a first waste acid outlet 22 to the bottom of the desorption tower 5; the low-solid-content waste acid moves toward the central axis, forms an inner vortex moving upward at the center of the axis, and then spirally rises to an ORP flow cell 3 (as shown in Figure 2 ) from the outlet at the top of the cyclone 2;

[0051] 3) The low-solid-content waste acid contacts the detection probe 31, the rotation scouring detection probe 31 slows down the aggregation and coating of solids on the probe, and then flows into the desorption tower 5 from the third waste acid outlet 32 in the side wall.

[0052] 4) The cut-off valve 211 on the pipeline of the first waste acid inlet 21 of the cyclone 2 is automatically closed every 4 h, and the switch valve 331 on the pipeline of the side wall flushing water outlet 33 of the ORP flow cell 3 is opened at the same time to flush the detection probe 31, the flushing water pressure is 0.3 MPa, and the solids accumulated around the detection probe 31 are removed;

[0053] 5) The waste acid from the waste acid delivery pump 1 enters the upper part of the desorption tower 5 from the spray inlet 51, is in countercurrent contact with the air containing hydrogen sulfide gas collected by the gas collector 4 entering from the air inlet 52 in the side wall of the desorption tower 5 from top to bottom, and the hydrogen sulfide gas in the waste acid is removed; the gas desorbed from the desorption tower 5 is sent to a harm-removing tower for harmless treatment through the negative pressure suction of the top outlet 55 of the desorption tower 5; the gas pressure in the desorption tower 5 is-3 kPa, the liquid-gas ratio is 7×10 -3 m 3 / Nm 3 , and the liquid spray density is 30 m 3 / (m 2 ·h);

[0054] 6) The waste acid from the cyclone 2 and ORP flow cell 3 is combined with the waste acid from the stripping column 5 and is sent to the thickener for treatment by the waste acid feed pump 6.

[0055] The present application effectively reduces the frequency of manual disassembly and cleaning of the ORP detection probe 31, from once a week before the improvement to once every two months after the improvement, which improves the operating environment near the ORP flow cell 3, reduces the overflow of hydrogen sulfide from an average of 200 mg / h before the improvement to an average of 80 mg / h after the improvement, greatly reduces the overflow of hydrogen sulfide during the waste acid filter pressing process, and improves the operating environment of the waste acid filter press room.

Claims

1. A method for ensuring the detection of the oxidation-reduction potential of waste acid, characterized by, The process is as follows: 1) the waste acid from the sulfidation reactor is transported by a waste acid delivery pump (1) to a cyclone (2) and a desorption tower (5) through pipelines respectively; 2) the waste acid transported to the cyclone (2) enters the cyclone (2) along the tangent direction, and preliminary liquid-solid separation is carried out in the cyclone (2), the inlet waste acid is separated into high solid content waste acid and low solid content waste acid, wherein the high solid content waste acid moves downward along the axial direction under the action of the cyclone field, then moves outward along the radial direction, reaches the conical section, moves downward along the inner wall of the cyclone (2) to the first waste acid outlet (22) at the bottom, and flows to the bottom of the desorption tower (5); the low solid content waste acid moves towards the central axis, forms an upward inner vortex at the center of the axis, and then spirally rises from the outlet at the top of the cyclone (2) to the ORP flow cell (3); 3) the low solid content waste acid contacts with the detection probe (31), the rotation scouring of the detection probe (31) slows down the accumulation and coating of solids on the probe, and then flows into the desorption tower (5) from the third waste acid outlet (32) on the side wall; 4) a shut-off valve (211) is arranged on the pipeline of the first waste acid inlet (21) of the cyclone (2), the shut-off valve (211) is automatically closed every certain time, at the same time, an on-off valve (331) on the pipeline of the side wall flushing water outlet (33) of the ORP flow cell (3) is opened, the detection probe (31) is flushed, and the solids accumulated around the detection probe (31) are removed; 5) the waste acid from the waste acid delivery pump (1) enters the upper part of the desorption tower (5) from the spray inlet (51), and is in countercurrent contact with the air containing hydrogen sulfide gas collected by the gas collecting hood (4) entering from the air inlet (52) on the side wall of the desorption tower (5) from top to bottom, so as to remove the hydrogen sulfide gas in the waste acid; the desorbed gas containing hydrogen sulfide is sent to a harm removal tower for harmless treatment through the negative pressure suction of the top outlet (55) of the desorption tower (5); 6) the waste acid from the cyclone (2) and the ORP flow cell (3) is combined with the waste acid in the desorption tower (5), and then is transported to a thickener for treatment by a waste acid supply pump (6).

2. The waste acid oxidation-reduction potential detection guarantee method according to claim 1, characterized in that, The certain time is 2-6h.

3. The method of claim 1, wherein the method further comprises: The flushing water pressure of the ORP flow cell (3) is 0.1-0.3MPa.

4. The waste acid oxidation-reduction potential detection guarantee method according to claim 1, characterized in that, The gas pressure in the desorption tower (5) is -4.0 to -1.0 kPa, the liquid-gas ratio is 5 to 10 x 10 -3 m 3 / Nm 3 , and the liquid spray density is 20 to 30 m 3 / .

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