Method for rapidly estimating arsenic content in arsenic-containing waste acid and arsenic removal method for arsenic-containing waste acid

Abstract

The invention relates to a method for rapidly estimating the content of arsenic in arsenic-containing waste acid, which comprises the following steps: obtaining a to-be-detected sample, filtering, adding a sodium hydrosulfide solution into the filtrate, shaking uniformly to obtain a reaction solution, and judging the content of arsenic in the to-be-detected sample according to the color of the reaction solution, the volume ratio of the filtrate to the sodium hydrosulfide solution being 50: 0.09-0.11. According to the method, the to-be-detected sample is obtained, the 30%-32% sodium hydrosulfide solution is added into the filtrate obtained after the to-be-detected sample is filtered, the content of arsenic in the to-be-detected sample can be rapidly estimated by observing the color of the reaction solution, detection can be conducted on the edge of a vulcanization reaction tank, the detection speed is high, the cost is low, the dosage of a vulcanization agent can be rapidly adjusted, and the detection efficiency is high. Excessive or too small addition amount of the vulcanizing agent is avoided, and the waste acid treatment cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-arsenic wastewater from copper smelting, and particularly relates to a method for rapidly estimating the arsenic content in arsenic-containing waste acid and a method for removing arsenic from the arsenic-containing waste acid. Background Art

[0002] Generally, the waste acid and sewage treatment process of copper smelting sulfuric acid workshop adopts the "primary sulfidation copper removal + secondary (two-stage) sulfidation arsenic removal + limestone neutralization method". The sulfiding agent is reacted with the heavy metal-containing waste acid to purify and separate copper, arsenic and other heavy metal ions to form copper-rich slag and arsenic-rich slag. In the secondary sulfidation arsenic removal process, the waste acid after copper removal is first passed into the primary sulfidation reaction tank, and a sulfiding agent such as sodium sulfide, sodium hydrosulfide or hydrogen sulfide is added at the same time. The sulfiding agent reacts continuously with the heavy metal-containing waste acid, and the formed sulfided slag is precipitated and separated. The supernatant enters the secondary sulfidation reaction tank, and the sulfiding agent is added again to further remove arsenic in the waste acid. The waste acid after sulfidation is then reacted with limestone slurry to neutralize the acidity and produce industrial gypsum slag. The treated recycled water is all reused, mainly for water quenching in the smelting slag field, lime milk preparation and raw material concentrate spraying, achieving zero emissions.

[0003] The waste acid sulfidation process contains high levels of arsenic and heavy metals, resulting in a short service life of the potentiometer. In addition, the dosage of the sulfiding agent needs to be adjusted according to the arsenic content in the waste acid to avoid adding too little or too much sulfiding agent. The existing industrial method for determining arsenic content is generally spectrophotometry or inductively coupled plasma emission spectrometry. After sampling from the production site, it is taken to the laboratory for testing. The efficiency of laboratory determination of arsenic content is low and the cost is high, making it unsuitable for production adjustment. Summary of the Invention

[0004] The object of the present invention is to provide a method for quickly estimating the arsenic content in arsenic-containing waste acid and a method for removing arsenic from arsenic-containing waste acid, which can quickly estimate the arsenic content in the waste acid and thus adjust the dosage of the sulfiding agent;

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A method for rapidly estimating the arsenic content in arsenic-containing waste acid comprises the following steps:

[0007] Obtain a sample to be tested, filter it, add a sodium hydrosulfide solution to the filtrate, shake well to obtain a reaction solution, and judge the arsenic content in the sample to be tested based on the color of the reaction solution, wherein the volume ratio of the filtrate to the sodium hydrosulfide solution is 50:0.09-0.11.

[0008] Preferably, the concentration of the sodium hydrosulfide solution is 30% to 32%.

[0009] Preferably, the colors of the reaction solutions corresponding to the arsenic content in the sample to be detected are dark yellow, light yellow, transparent and milky white in descending order.

[0010] Preferably, when the reaction solution is dark yellow, the arsenic content in the sample to be tested is greater than 3000 mg / L;

[0011] When the reaction solution is light yellow, the arsenic content in the sample to be tested is between 600 and 3000 mg / L;

[0012] When the reaction solution is transparent, the arsenic content in the sample to be tested is between 300 and 600 mg / L;

[0013] When the reaction solution is milky white, the arsenic content in the sample to be tested is less than 5 mg / L.

[0014] On the other hand, the present invention provides a method for removing arsenic from arsenic-containing waste acid, comprising the following steps: using a sulfide arsenic removal method, during the arsenic removal process, using the above-mentioned method for rapidly estimating the arsenic content in arsenic-containing waste acid to detect the waste acid, and adjusting the amount of sulfide according to the color of the reaction solution.

[0015] Preferably, the sulfide arsenic removal method is a two-stage sulfide arsenic removal method, which specifically comprises the following steps:

[0016] Passing the waste acid into a primary vulcanization reaction tank, adding a first predetermined amount of a vulcanizing agent to obtain a vulcanization filtrate, sampling the waste acid supernatant in the primary vulcanization reaction tank for detection, and when the reaction liquid is dark yellow, increasing the amount of the vulcanizing agent added to the primary vulcanization reaction tank or reducing the amount of liquid fed into the primary vulcanization reaction tank; when the reaction liquid is transparent or milky white, reducing the amount of the vulcanizing agent added to the primary vulcanization reaction tank or increasing the amount of liquid fed into the primary vulcanization reaction tank;

[0017] After the sulfide filtrate flows into the secondary sulfide reaction tank, a second predetermined amount of sulfiding agent is added, and the supernatant of the sulfide filtrate in the secondary sulfide reaction tank is sampled for detection. When the color of the reaction liquid is light yellow, the amount of sulfiding agent added to the secondary sulfide reaction tank is increased or the amount of liquid fed into the secondary sulfide reaction tank is reduced; when the color of the reaction liquid is milky white, the amount of sulfiding agent added to the secondary sulfide reaction tank is reduced or the amount of liquid fed into the secondary sulfide reaction tank is increased.

[0018] Preferably, when the waste acid supernatant in the primary vulcanization reaction tank is detected and the reaction liquid color is dark yellow, the amount of vulcanizing agent added to the primary vulcanization reaction tank is increased or the liquid inlet amount of the primary vulcanization reaction tank is reduced, and the amount of vulcanizing agent added to the secondary vulcanization reaction tank is increased or the liquid inlet amount of the secondary vulcanization reaction tank is reduced; when the reaction liquid color is transparent or milky white, the amount of vulcanizing agent added to the primary vulcanization reaction tank is reduced or the liquid inlet amount of the primary vulcanization reaction tank is increased, and the amount of vulcanizing agent added to the secondary vulcanization reaction tank is reduced.

[0019] The present invention obtains a sample to be tested, adds a 30% to 32% sodium hydrosulfide solution to the filtrate after filtering the sample to be tested, and observes the color of the reaction liquid to quickly estimate the arsenic content in the sample to be tested. The method can be used at the edge of a sulfidation reaction tank, with high detection speed and low cost. The dosage of the sulfiding agent can be quickly adjusted to avoid excessive or insufficient dosage of the sulfiding agent, thereby conveniently reducing the cost of waste acid treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the test result diagram of Example 1;

[0021] Figure 2 This is the test result diagram of Example 2;

[0022] Figure 3 This is the test result diagram of Example 3;

[0023] Figure 4 This is the test result diagram of Example 4. DETAILED DESCRIPTION

[0024] The present invention is further described below with reference to the accompanying drawings and specific embodiments.

[0025] The present invention provides a method for rapidly estimating the arsenic content in arsenic-containing waste acid, comprising the following steps:

[0026] Obtain a sample to be tested, filter the sample to be tested through rapid qualitative filter paper, weigh the filtered filtrate, add a sodium hydrosulfide solution to the filtrate, shake well to obtain a reaction solution, and judge the arsenic content in the sample to be tested based on the color of the reaction solution, wherein the volume ratio of the filtrate to the sodium hydrosulfide solution is 50:0.09-0.11, and the concentration of the sodium hydrosulfide solution is 30%-32%.

[0027] Specifically, the colors of the reaction solution corresponding to the arsenic content in the sample to be detected are dark yellow, light yellow, transparent and milky white, from large to small. When the color of the reaction solution is dark yellow, the arsenic content in the sample to be detected is greater than 3000 mg / L;

[0028] When the reaction solution is light yellow, the arsenic content in the sample to be tested is between 600 and 3000 mg / L;

[0029] When the reaction solution is transparent, the arsenic content in the sample to be tested is between 300 and 600 mg / L;

[0030] When the reaction solution is milky white, the arsenic content in the sample to be tested is less than 5 mg / L.

[0031] On the other hand, the present invention provides a method for removing arsenic from arsenic-containing waste acid, comprising the following steps: using a sulfide arsenic removal method, during the arsenic removal process, using the above-mentioned method for rapidly estimating the arsenic content in arsenic-containing waste acid to detect the waste acid, and adjusting the amount of sulfide according to the color of the reaction solution.

[0032] Specifically, the sulfide arsenic removal method is a two-stage sulfide arsenic removal method, which specifically includes the following steps:

[0033] Passing the waste acid into a primary vulcanization reaction tank, adding a first predetermined amount of a vulcanizing agent to obtain a vulcanization filtrate, sampling the waste acid supernatant in the primary vulcanization reaction tank for detection, and when the reaction liquid is dark yellow, increasing the amount of the vulcanizing agent added to the primary vulcanization reaction tank or reducing the amount of liquid fed into the primary vulcanization reaction tank; when the reaction liquid is transparent or milky white, reducing the amount of the vulcanizing agent added to the primary vulcanization reaction tank or increasing the amount of liquid fed into the primary vulcanization reaction tank;

[0034] After the sulfide filtrate flows into the secondary sulfide reaction tank, a second predetermined amount of sulfiding agent is added, and the supernatant of the sulfide filtrate in the secondary sulfide reaction tank is sampled for detection. When the color of the reaction liquid is light yellow, the amount of sulfiding agent added to the secondary sulfide reaction tank is increased or the amount of liquid fed into the secondary sulfide reaction tank is reduced; when the color of the reaction liquid is milky white, the amount of sulfiding agent added to the secondary sulfide reaction tank is reduced or the amount of liquid fed into the secondary sulfide reaction tank is increased.

[0035] More specifically, when the waste acid supernatant in the primary sulfidation reaction tank is detected and the reaction liquid color is dark yellow, the amount of sulfiding agent added to the primary sulfidation reaction tank is increased or the liquid inlet amount to the primary sulfidation reaction tank is reduced, and the amount of sulfiding agent added to the secondary sulfidation reaction tank is increased or the liquid inlet amount to the secondary sulfidation reaction tank is reduced; when the reaction liquid color is transparent or milky white, the amount of sulfiding agent added to the primary sulfidation reaction tank is reduced or the liquid inlet amount to the primary sulfidation reaction tank is increased, and the amount of sulfiding agent added to the secondary sulfidation reaction tank is reduced.

[0036] More specifically, in the waste acid wastewater treatment process, the first-level sulfidation copper removal method is adopted, the waste acid is passed into the sulfidation copper removal reaction tank, the sulfidation agent is added to react with the waste acid to remove copper and part of arsenic in the waste acid, and then enters the copper removal thickener for separation, and then the second-level sulfidation arsenic removal method is adopted, the waste acid after copper removal is passed into the first-level sulfidation reaction tank, and during the liquid feeding process of the first-level sulfidation reaction tank, a first predetermined amount of sulfidation agent is added at the same time, the waste acid reacts with the sulfidation agent, and the supernatant of the waste acid overflow flows into the first thickener for solid-liquid separation to obtain sulfidation filtrate, and in the first-level sulfidation reaction tank, the waste acid is separated into the first sulfidation filtrate. The supernatant of the waste acid is taken from the tank for testing. If the reaction liquid is light yellow, the arsenic content of the waste acid supernatant is between 600 and 3000 mg / L, and the first predetermined amount of the sulfiding agent is appropriate. If the reaction liquid is dark yellow, it proves that the arsenic content of the initial waste acid is high, and it is necessary to increase the amount of the sulfiding agent added or reduce the amount of liquid fed on the basis of the first predetermined amount. If the reaction liquid is transparent or milky white, it proves that the arsenic content of the initial waste acid is low, and the amount of the sulfiding agent added or the amount of liquid fed can be reduced on the basis of the first predetermined amount, thereby reducing the cost of waste acid treatment.

[0037] Among them, if the color of the reaction liquid is dark yellow, the amount of vulcanizing agent added to the secondary vulcanization reaction tank can be increased or the amount of liquid fed to the secondary vulcanization reaction tank can be reduced at the same time. When the color of the reaction liquid is transparent or milky white, the amount of vulcanizing agent added to the secondary vulcanization reaction tank can be reduced at the same time, so as to facilitate the timely treatment of the supernatant of the waste acid overflow in the primary vulcanization reaction tank.

[0038] The sulfide filtrate of the first thickener flows into the secondary sulfide reaction tank. During the liquid feeding process of the secondary sulfide reaction tank, a second predetermined amount of sulfiding agent is added at the same time. The sulfide filtrate reacts with the sulfiding agent again. The supernatant of the sulfide filtrate overflows and flows into the second thickener for solid-liquid separation. The supernatant of the sulfide filtrate is taken from the secondary sulfide reaction tank for detection. If the color of the reaction liquid is transparent, the arsenic content of the sulfide filtrate is between 300 and 600 mg / L, and the second predetermined amount of sulfiding agent is appropriate. When the color of the reaction liquid is light yellow, it proves that the arsenic content in the sulfide filtrate after the primary sulfide reaction is still high. On the basis of the second predetermined amount, the amount of sulfiding agent added is increased or the liquid feeding amount is reduced. When the color of the reaction liquid is milky white, it proves that the arsenic content in the sulfide filtrate after the primary sulfide reaction is low. On the basis of the second predetermined amount, Reducing the amount of sulfiding agent added or increasing the amount of liquid input facilitates reducing the cost of waste acid treatment, wherein the second predetermined amount is the planned amount of sulfiding agent added corresponding to reducing the arsenic content in the waste acid to about 1 mg / L. Since the waste acid and the sulfiding agent react continuously, the sulfiding filtrate and the sulfiding agent in the secondary sulfiding reaction tank have not yet completely reacted. When the arsenic content of the supernatant of the sulfiding filtrate in the secondary sulfiding reaction tank is between 300 and 600 mg / L, after the sulfiding filtrate and the sulfiding agent in the second thickener have completely reacted, the arsenic content of the sulfiding filtrate is about 1 mg / L. After the reaction of the sulfiding agent in the second thickener is completed, whether the arsenic content reaches the specified range is detected. At this time, the detection can use spectrophotometry, ICP inductively coupled plasma emission spectrometry or other methods to accurately measure the arsenic content.

[0039] More specifically, when the waste acid supernatant in the primary sulfidation reaction tank is detected and the reaction liquid color is dark yellow, the amount of sulfiding agent added to the primary sulfidation reaction tank is increased or the liquid inlet amount to the primary sulfidation reaction tank is reduced, and the amount of sulfiding agent added to the secondary sulfidation reaction tank is increased or the liquid inlet amount to the secondary sulfidation reaction tank is reduced; when the reaction liquid color is transparent or milky white, the amount of sulfiding agent added to the primary sulfidation reaction tank is reduced or the liquid inlet amount to the primary sulfidation reaction tank is increased, and the amount of sulfiding agent added to the secondary sulfidation reaction tank is reduced.

[0040] To further illustrate the present invention, a method for rapidly estimating the arsenic content in arsenic-containing waste acid is described in detail below with reference to examples.

[0041] Example 1

[0042] Obtain the sample to be tested, filter it with a rapid qualitative filter paper, weigh 50 mL of the filtered filtrate, add 2 drops of 30% to 32% sodium hydrosulfide solution (0.1 mL) to the filtrate using a dropper, and shake well to obtain a reaction solution. Figure 1 As shown, the reaction solution was dark yellow in color, and the arsenic content was determined to be 3886 mg / L after being sent for testing.

[0043] Example 2

[0044] Obtain the sample to be tested, filter it with a rapid qualitative filter paper, weigh 50 mL of the filtered filtrate, add 2 drops of 30% to 32% sodium hydrosulfide solution (0.1 mL) to the filtrate using a dropper, and shake well to obtain a reaction solution. Figure 2 As shown, the reaction solution was light yellow in color, and the arsenic content was determined to be 1470 mg / L.

[0045] Example 3

[0046] Obtain the sample to be tested, filter it with a rapid qualitative filter paper, weigh 50 mL of the filtered filtrate, add 2 drops of 30% to 32% sodium hydrosulfide solution (0.1 mL) to the filtrate using a dropper, and shake well to obtain a reaction solution. Figure 3 As shown, the reaction solution is transparent, and the arsenic content is 569 mg / L when sent for testing.

[0047] Example 4

[0048] Obtain the sample to be tested, filter it with a rapid qualitative filter paper, weigh 50 mL of the filtered filtrate, add 2 drops of 30% to 32% sodium hydrosulfide solution (0.1 mL) to the filtrate using a dropper, and shake well to obtain a reaction solution. Figure 4 As shown, the reaction solution was milky white in color, and the arsenic content was determined to be 1.13 mg / L.

Claims

1. A method for rapidly estimating the arsenic content in arsenic-containing waste acid, characterized in that: The following steps are involved: Obtain a sample to be tested, filter it, add a sodium hydrosulfide solution to the filtrate, shake well to obtain a reaction solution, and judge the arsenic content in the sample to be tested based on the color of the reaction solution, wherein the volume ratio of the filtrate to the sodium hydrosulfide solution is 50:0.09-0.

11.

2. The method for rapidly estimating the arsenic content in arsenic-containing waste acid according to claim 1, characterized in that: The concentration of the sodium hydrosulfide solution is 30% to 32%.

3. The method for rapidly estimating the arsenic content in arsenic-containing waste acid according to claim 1, characterized in that: The colors of the reaction solutions corresponding to the arsenic content in the sample to be detected are dark yellow, light yellow, transparent and milky white in descending order.

4. The method for rapidly estimating the arsenic content in arsenic-containing waste acid according to claim 1, characterized in that: When the reaction solution is dark yellow, the arsenic content in the sample to be tested is greater than 3000 mg / L; When the reaction solution is light yellow, the arsenic content in the sample to be tested is between 600 and 3000 mg / L; When the reaction solution is transparent, the arsenic content in the sample to be tested is between 300 and 600 mg / L; When the reaction solution is milky white, the arsenic content in the sample to be tested is less than 5 mg / L.

5. A method for removing arsenic from arsenic-containing waste acid, characterized in that: The following steps are involved: The arsenic removal method using sulfide is used. During the arsenic removal process, the waste acid is tested using the method for rapidly estimating the arsenic content in arsenic-containing waste acid as described in any one of claims 1 to 4, and the amount of sulfide is adjusted according to the color of the reaction solution.

6. The method for removing arsenic from arsenic-containing waste acid according to claim 5, characterized in that: The sulfide arsenic removal method is a two-stage sulfide arsenic removal method, which specifically includes the following steps: Passing the waste acid into a primary vulcanization reaction tank, adding a first predetermined amount of a vulcanizing agent to obtain a vulcanization filtrate, sampling the waste acid supernatant in the primary vulcanization reaction tank for detection, and when the reaction liquid is dark yellow, increasing the amount of the vulcanizing agent added to the primary vulcanization reaction tank or reducing the amount of liquid fed into the primary vulcanization reaction tank; when the reaction liquid is transparent or milky white, reducing the amount of the vulcanizing agent added to the primary vulcanization reaction tank or increasing the amount of liquid fed into the primary vulcanization reaction tank; After the sulfide filtrate flows into the secondary sulfide reaction tank, a second predetermined amount of sulfiding agent is added, and the supernatant of the sulfide filtrate in the secondary sulfide reaction tank is sampled for detection. When the color of the reaction liquid is light yellow, the amount of sulfiding agent added to the secondary sulfide reaction tank is increased or the amount of liquid fed into the secondary sulfide reaction tank is reduced; when the color of the reaction liquid is milky white, the amount of sulfiding agent added to the secondary sulfide reaction tank is reduced or the amount of liquid fed into the secondary sulfide reaction tank is increased.

7. The method for removing arsenic from arsenic-containing waste acid according to claim 6, characterized in that: When the waste acid supernatant in the primary vulcanization reaction tank is detected and the reaction liquid color is dark yellow, the amount of vulcanizing agent added to the primary vulcanization reaction tank is increased or the liquid inlet amount to the primary vulcanization reaction tank is reduced, and the amount of vulcanizing agent added to the secondary vulcanization reaction tank is increased or the liquid inlet amount to the secondary vulcanization reaction tank is reduced; when the reaction liquid color is transparent or milky white, the amount of vulcanizing agent added to the primary vulcanization reaction tank is reduced or the liquid inlet amount to the primary vulcanization reaction tank is increased, and the amount of vulcanizing agent added to the secondary vulcanization reaction tank is reduced.

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