CN111762927A - Method and device for joint demercuration of high-acidity chemical mercury-containing waste acid liquid - Google Patents

Method and device for joint demercuration of high-acidity chemical mercury-containing waste acid liquid Download PDF

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CN111762927A
CN111762927A CN202010541284.0A CN202010541284A CN111762927A CN 111762927 A CN111762927 A CN 111762927A CN 202010541284 A CN202010541284 A CN 202010541284A CN 111762927 A CN111762927 A CN 111762927A
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mercury
liquid
acid
storage tank
adsorption
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孙荣林
梅云峰
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Tangshan Zhou Xing Science And Technology Development Co ltd
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Tangshan Zhou Xing Science And Technology Development Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water, or sewage
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/281—Treatment of water, waste water, or sewage by sorption using inorganic sorbents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/283—Treatment of water, waste water, or sewage by sorption using coal, charred products, or inorganic mixtures containing them
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/46104—Devices therefor; Their operating or servicing
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/20—Heavy metals or heavy metal compounds

Abstract

A method and a device for joint demercuration of high-acidity chemical mercury-containing waste acid liquid relate to the field of mercury treatment. The device is composed of a diaphragm electrodeposition unit, a continuous sulfuration demercuration unit and an adsorption demercuration unit which are connected in sequence, and can realize continuous and efficient removal of mercury in any form in the high-acidity mercury-containing waste acid liquid. The method can continuously and rapidly remove the mercury in the high-acidity mercury-containing waste acid liquid by utilizing the combined process technology of the diaphragm electrolytic deposition method, the continuous vulcanization method and the adsorbent demercuration method, so that the mercury is precipitated and removed in the form of metallic mercury and mercury sulfide, and the mercury in the mercury-containing waste acid liquid can be recovered after being collected, wherein the electrolytic deposition method is small in occupied space, environment-friendly and pollution-free, and the final mercury is precipitated in the form of metallic mercury regardless of organic mercury or inorganic mercury, so that the mercury content of the high-acidity waste liquid can be effectively reduced; the hydrogen sulfide gas of the continuous vulcanization method circulates in a closed manner in the system, pollution is avoided, deep purification in the waste liquid can be guaranteed by the adsorbent mercury removal method, and comprehensive utilization of the purified acid liquid is facilitated.

Description

Method and device for joint demercuration of high-acidity chemical mercury-containing waste acid liquid
Technical Field
The invention relates to the field of mercury treatment, in particular to a method and a device for joint demercuration of high-acidity chemical mercury-containing waste acid liquid.
Background
Mercury and its compounds have become the priority pollutants in china and even the world due to their characteristics of biotoxicity, bioaccumulation, durability, long-distance transport, etc. China is a big country for producing, using and discharging mercury, the mercury production and usage amount respectively account for about 60% of the global production and usage amount, and the mercury production and usage can cause the discharge of mercury-containing waste. Mercury and its compounds discharged into water body can be formed into various forms of mercury through physical, chemical and biological actions, and can be converted into methyl compounds with large toxicity. The water genus occurring in Japan is caused by the contamination of water areas with methyl mercury chloride discharged from chemical plants.
The traditional treatment method for mercury-containing wastewater mainly comprises a chemical precipitation method, a metal reduction method, an activated carbon adsorption method, an ion exchange method, an electrolysis method, a microbiological method and the like.
The precipitation method is a relatively common mercury treatment method, can treat mercury salts with different concentrations and different types, and is commonly used in a coagulating precipitation method and a sulfide precipitation method.
The principle of the precipitation method is that coagulant (lime, iron salt and aluminum salt) is added into mercury-containing wastewater, and under the condition that the pH value is 8-10 and alkalescence is achieved, hydroxide flocculating constituents are formed, mercury is flocculated, and mercury is precipitated through coprecipitation. The sulfide precipitation method utilizes Na under alkaline condition2S, MgS S2-With Hg+/Hg2+Has stronger affinity, generates mercury sulfide precipitate with small active solubility and is removed from the solution.
The method is to utilize the electrochemical property of metal, under the action of direct current, the mercury compound is dissociated into mercury ions at the anode and reduced into metallic mercury at the cathode, thereby removing the mercury in the wastewater. However, this method has the disadvantage that the concentration of mercury ions in the water cannot be reduced very low. Therefore, the electrolysis method is not suitable for treating the wastewater containing low-concentration mercury ions, and the method has high power consumption and high investment cost.
The exchange method can remove mercury ions from a solution at a low concentration, compared with the precipitation method and the electrolysis method. The ion exchange method is carried out in an ion exchanger, and the mercury ions are absorbed by macroporous mercapto (-SH) ion exchange resin, so as to achieve the aim of removing the mercury ions in water. This process is reversible and the ion exchange resin can be regenerated, typically for secondary treatment. The resin was eluted with 40 times of concentrated hydrochloric acid, the elution rate being 90%. But the process is limited by the influence of impurities in the waste water and by the type, yield and cost of the exchanger.
The method for removing mercury mainly comprises the following steps: activated carbon adsorption, chitin adsorption, zeolite molecular sieve adsorption, modified bentonite adsorption, fly ash adsorption, corncob powder adsorption and husk ash adsorption. The modified rice hull, bagasse, soybean hull, sawdust, coconut shell, peanut shell, apple core and fly ash can be used as adsorbent for treating mercury. The activated carbon has a large surface area, and oxygen-containing functional groups (-COOH, -OH, -C ═ O) are formed in the activation process, so that the activated carbon has the functions of chemical adsorption and catalytic oxidation and reduction, and can effectively remove heavy metals. The activated carbon is used for treating the wastewater with high mercury content, so that high removal rate (85-99%) can be obtained. The waste water with low mercury content is treated, and effluent with low mercury content can be obtained although the removal rate is not high enough.
The absorption method is a method of using wool as a protein, and the amino acids constituting the protein contain cystine, and the protein is bonded to disulfide to crosslink wool molecules, but the bonding can be cleaved into mercapto groups by reduction reaction, hydrolysis with water, action of enzymes, and the like, and heavy metals such as mercury easily react with the mercapto groups, so that the modified wool having the mercapto groups can trap heavy metals. The modified wool has good trapping capacity on trace mercury, and a post-treatment method of the wool absorbing mercury must be researched at present.
According to the electrode potential theory, metal (scraps or powder) with low toxicity such as zinc, aluminum, magnesium, manganese and the like and low electrode potential is used for replacing mercury ions from the wastewater, wherein the effect of iron and zinc is better. For example, in the iron scrap reduction method, the treatment effect is better when the pH value is 7-8, and about 40kg of industrial iron powder can remove 1kg of mercury. The metal reduction method is suitable for treating mercury-containing wastewater with single component, has high reaction rate, can directly recover metal mercury, but has incomplete mercury removal and needs to be combined with other methods for use.
The extraction method uses solvent to extract trace mercury in wastewater, uses xylene solution containing triisooctylamine to extract HgCl4 2-Extracted as a complex and then back-extracted in aqueous solution. The method can be only used for a small amount of mercury-containing wastewater.
Compared with the traditional physical and chemical method, the physical method has the following advantages: the operation cost is low, and the amount of chemical or biological sludge to be treated is small; the efficiency of removing the waste liquid with extremely low concentration of heavy metal ions is high; wide operation pH and temperature range (pH 3-9, temperature 4-90 ℃): high adsorption rate and selectivity. Moreover, the microbiological method is particularly effective in treating the wastewater with the mercury mass concentration of 1-100 mg/L. The microbiological method makes up the defect that the mass fraction of mercury ions in the sewage cannot be reduced to 10-9 levels by the existing process, and the novel and unique advantages of the microbiological method are increasingly paid more attention.
The method mainly treats the mercury-containing heavy metal wastewater or low-acidity mercury-containing wastewater, but the conventional method cannot realize the acid with the mass fraction of more than 30%. Although the prior art has the demercuration technology in high-acidity acid, the demercuration in the prior art is not thorough and can not meet the requirement of stable standard.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a method and a device for jointly removing mercury from high-acidity chemical mercury-containing waste acid liquid.
The technical scheme adopted by the invention is as follows: a combined demercuration device for high-acidity chemical mercury-containing waste liquid, which has the technical key points that,
the system at least comprises an acid pump, a waste liquid storage tank, an electrolytic deposition tank, a simple substance mercury storage tank, a primary demercuration liquid storage tank, a first jet pipe, a second jet pipe, a hydrogen sulfide generator, a hydrogen sulfide gas transmission pipe, a hydrogen sulfide storage tank, a continuous vulcanization reaction device, a mercury release stop valve, a slurry pump, a solid-liquid separator, a sludge receiving tank, a secondary purification liquid adsorption tank, a liquid outlet pipe and a sludge release stop valve;
the upper inlet of the waste liquid storage tank is connected with high-acidity high-mercury-containing waste liquid, the lower outlet of the waste liquid storage tank is communicated with the solution inlet of the diaphragm electrolytic deposition tank through a pipeline, the bottom opening of the diaphragm electrolytic deposition tank is connected with the elemental mercury storage tank through a pipeline, and the side liquid outlet of the diaphragm electrolytic deposition tank is connected with the primary demercuration liquid storage tank through a pipeline;
the jet pipe and the jet pipe are hermetically arranged in the continuous vulcanization reaction device, the liquid outlet of the primary mercury removal liquid storage tank is respectively connected with the solution inlet of the jet pipe and the solution inlet of the jet pipe through pipelines, the outlet at the bottom of the continuous vulcanization reaction device is connected with the inlet of the solid-liquid separator through an acid-resistant pipeline, and the lower end of the unloading flange of the solid-liquid separator is provided with a sludge receiving tank; the outlet of the liquid receiving disc of the solid-liquid separator is connected with the inlet of the secondary purified liquid adsorption tank through a liquid pipeline;
the outlet of the secondary purifying liquid adsorption tank is connected with the liquid inlet of the hydrogen sulfide generator through a pipeline, the other inlet of the secondary purifying liquid adsorption tank is connected with the liquid outlet of the continuous vulcanization reaction device, and the liquid outlet of the secondary purifying liquid adsorption tank is connected with the liquid outlet pipe.
In the scheme, a first acid-resistant pump is installed on a communication pipeline between an upper inlet of the waste acid storage tank and the high-acidity high-mercury-containing waste liquid, a second acid-resistant pump is arranged on a communication pipeline between the diaphragm electrowinning tank and the waste acid storage tank, a third acid-resistant pump is installed on a pipeline which is communicated with the jet pipe and the jet pipe together in the primary mercury removing liquid storage tank, a slurry pump is installed on a pipeline which is communicated with an outlet at the bottom of the continuous vulcanization reaction device, and a fourth acid-resistant pump is installed on a pipeline which is connected between the solid-liquid separator and the secondary purifying liquid adsorption tank.
In the scheme, a mercury release stop valve is arranged on a communication pipeline between the lower outlet of the diaphragm electrolytic deposition tank and the elemental mercury storage tank.
In the scheme, a gas booster pump is arranged on a common communication pipeline of the hydrogen sulfide storage tank, the first jet pipe air inlet and the second jet pipe air inlet.
In the scheme, the gas pipeline communicated between the gas outlet of the hydrogen sulfide generator and the inlet of the hydrogen sulfide storage tank is provided with the gas stop valve and the pressure gauge.
A method for jointly removing mercury from high-acidity chemical mercury-containing waste liquid is technically characterized by comprising the following steps:
step 1, carrying out membrane electrodeposition demercuration, wherein the mercury concentration in the initial high-acidity chemical mercury-containing waste liquid is 8000-12000 mg/L, and the acid concentration is 30-35%; taking a graphite polar plate as an anode, a stainless steel polar plate as a cathode, and a cation exchange membrane or teryleneThe cloth bag is a diaphragm, and the current density of the diaphragm electro-deposition cathode is 50-100A/m2The homopolar distance is 80-100 mm, the additive thiourea is 0.5-1 g/L, the electrodeposition time is 60-90 min, and electrolytic mercury and a primary demercuration acid solution are obtained after deposition;
step 2, continuously carrying out sulfuration and demercuration, namely, carrying out hydrogen sulfide reaction by using high-acidity chemical mercury-containing waste liquid as acid liquid and one or more of sodium sulfide, iron sulfide and pyrite as a sulfur source, wherein the prepared hydrogen sulfide is controlled according to the molar ratio of S to Hg of 3-5; introducing hydrogen sulfide gas into a gas inlet of a jet pipe, introducing a primary demercuration acid solution into the solution inlet of the jet pipe, continuously reacting for 2.0-3.0 h, and enabling the concentration of mercury in the treated secondary purified liquid to be lower than 20 mg/L;
and 3, deeply adsorbing and removing mercury, namely allowing the secondary purified liquid to enter a secondary purified liquid adsorption tank for adsorbing and removing mercury, wherein the adopted adsorbent is one or more of acid-resistant mercury adsorption material, modified bentonite, modified clay or sulfur-loaded activated carbon, modified activated coke and the like, and a tertiary purified liquid with mercuric sulfide precipitate and mercury concentration lower than 0.03mg/L is obtained after adsorption.
In the above scheme, the adsorption demercuration in step 3 adopts a three-stage series connection mode, and the first and second-stage adsorption columns respectively comprise from the bottom layer to the upper layer: acid-resistant mercury adsorption materials are filled in the bottom layer and the middle layer, modified bentonite or modified clay is filled in the upper layer, and sulfur-loaded active carbon or modified active coke is filled in the third-level adsorption columns.
The invention has the beneficial effects that: the device for jointly removing mercury from the high-acidity chemical mercury-containing waste acid liquid comprises a diaphragm electrodeposition unit, a continuous vulcanization mercury removal unit and an adsorption mercury removal unit which are sequentially connected, can continuously and efficiently remove mercury in any form in the high-acidity mercury-containing waste acid liquid, directly and efficiently remove mercury in any form under the condition of not adjusting the pH value, and has the advantages of high efficiency, no pollution and recoverability; the method can continuously and rapidly remove the mercury in the high-acidity mercury-containing waste acid liquid by utilizing the combined process technology of the diaphragm electrolytic deposition method, the continuous vulcanization method and the adsorbent demercuration method, so that the mercury is precipitated and removed in the form of metallic mercury and mercury sulfide, and the mercury in the mercury-containing waste acid liquid can be recovered after being collected, wherein the electrolytic deposition method is small in occupied space, environment-friendly and pollution-free, and the mercury is precipitated in the form of metallic mercury in both organic mercury and inorganic mercury, so that the mercury content of the high-acidity waste liquid can be effectively reduced; the hydrogen sulfide gas of the continuous vulcanization method circulates in a closed manner in the system, pollution is avoided, deep purification in the waste liquid can be guaranteed by the adsorbent mercury removal method, and comprehensive utilization of the purified acid liquid is facilitated.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
FIG. 1 is a block diagram of a combined mercury removal device for high-acidity chemical mercury-containing waste liquid in an embodiment of the invention;
FIG. 2 is a flow chart of a combined mercury removal method for high-acidity chemical mercury-containing waste liquid in an embodiment of the invention;
the numbers in the figure illustrate the following: the device comprises an acid-proof pump 1, a waste liquid storage tank 2, an electrolytic deposition tank 3, an acid-proof pump 4, a simple substance mercury storage tank 5, a primary demercuration liquid storage tank 6, an acid-proof pump 7, a jet pipe 8, a jet pipe 9, a hydrogen sulfide generator 10, a gas delivery pipe 11, a hydrogen sulfide storage tank 12, a hydrogen sulfide gas return pipe 13, a continuous vulcanization reaction device 14, a mercury discharge stop valve 15, an acid-proof pump 16, a solid-liquid separator 17, a sludge receiving tank 18, a gas booster pump 19, an acid-proof pump 20, a secondary purification liquid adsorption tank 21, a sludge pump 22, a liquid outlet pipe 23 and a sludge discharge stop valve 24.
Detailed Description
The above objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings 1 and 2.
Example 1:
the combined demercuration device for the high-acidity chemical mercury-containing waste liquid in the embodiment comprises an acid-resistant pump (1, 4, 7, 20 and 22), a waste liquid storage tank 2, an electrolytic deposition tank 3, a simple substance mercury storage tank 5, a primary demercuration liquid storage tank 6, a jet pipe 8, a jet pipe 9, a hydrogen sulfide generator 10, a hydrogen sulfide storage tank 12, a continuous vulcanization reaction device 14, a mercury release stop valve 15, a slurry pump 16, a solid-liquid separator 17, a sludge receiving tank 18, a secondary purification liquid adsorption tank 21, a liquid outlet pipe 23 and a sludge release stop valve 24.
The combined demercuration device for the high-acidity chemical mercury-containing waste liquid in the embodiment comprises three parts:
(1) a diaphragm electrodeposition unit. The device comprises a waste liquid storage tank 2, an electrolytic deposition tank 3, a simple substance mercury storage tank 5 and a primary demercuration liquid storage tank 6, wherein the high-acidity high-mercury-content waste liquid is connected with an inlet of an acid-resistant pump 1 through a pipeline, and an outlet of the acid-resistant pump 1 is connected with an upper inlet of the waste liquid storage tank 2 through a pipeline. The lower outlet of the waste liquid storage tank 2 is communicated with the solution inlet of the diaphragm electrolytic deposition tank 3 through a pipeline, the bottom opening of the diaphragm electrolytic deposition tank 3 is connected with the elemental mercury storage tank 5 through a pipeline, and a stop valve is arranged on the pipeline. The liquid outlet at the side of the diaphragm electrowinning cell 3 is connected with a primary demercuration liquid storage tank 6 through a pipeline.
(2) A continuous sulfidation demercuration unit. The device comprises a jet pipe 8, a jet pipe 9, a continuous vulcanization reaction device 14, a solid-liquid separator 17 and a sludge receiving tank 18, wherein the jet pipe 8 and the jet pipe 9 are hermetically installed in the continuous vulcanization reaction device 14, and a sludge stop valve 24 is arranged at an outlet at the bottom of the continuous vulcanization reaction device 14. The liquid outlet of the primary demercuration liquid storage tank 6 is connected with the inlet of the acid-proof pump 7 through a pipeline, and the outlet of the acid-proof pump 7 is respectively connected with the solution inlet of the jet pipe 8 and the solution inlet of the jet pipe 9 through pipelines. The outlet at the bottom of the continuous vulcanization reaction device 14 is connected with the inlet of an acid-proof pump 16 through an acid-proof pipeline, and the outlet of a slurry pump 16 is connected with the inlet of a solid-liquid separator 17 through a pipeline. A sludge receiving tank 18 is arranged at the lower end of the discharging receiving disc of the solid-liquid separator 17; the outlet of the liquid receiving disc of the solid-liquid separator 17 is connected with the inlet of the acid-proof pump 20 through a liquid pipeline, and the outlet of the acid-proof pump 20 is connected with one inlet of the secondary purified liquid adsorption tank 21 through a pipeline. The other inlet of the secondary purified liquid adsorption tank 21 is connected to the outlet of the acid-resistant pump 22, and the inlet of the acid-resistant pump 22 is connected to the liquid outlet of the continuous vulcanization reaction device 14.
(3) And (4) an adsorption demercuration unit. Including a secondary purified liquid adsorption tank 21. The outlet of the secondary purifying liquid adsorption tank 21 is connected with the liquid inlet of the hydrogen sulfide generator 10 through a pipeline, and the liquid outlet of the secondary purifying liquid adsorption tank 21 is connected with the liquid outlet pipe 23. The hydrogen sulfide generator 10 is connected with an inlet of a hydrogen sulfide storage tank 12 through a gas delivery pipe 11, a gas outlet of the hydrogen sulfide storage tank 12 is connected with a gas inlet of a gas booster pump 19 through a pipeline, and a gas outlet of the gas booster pump 19 is communicated with gas inlets of the jet pipe 8 and the jet pipe 9 through a hydrogen sulfide gas return pipe 13. In the present embodiment, a stop valve and a pressure gauge are further installed on a gas pipeline communicating between the gas outlet of the hydrogen sulfide generator 10 and the inlet of the hydrogen sulfide storage tank 12. A pressure gauge and an alarm are also arranged on a gas pipeline connecting the outlet of the gas booster pump 19 with the gas inlets of the jet pipe 8 and the jet pipe 9.
The working process of the high-acidity chemical mercury-containing waste liquid combined demercuration device in the embodiment is as follows:
the high-acidity high-mercury-content chemical waste liquid enters an electrolytic deposition tank through a waste liquid storage tank, and electrolytic metal mercury and primary mercury removal liquid are obtained after electrodeposition; and the primary demercuration solution enters a continuous vulcanization reaction device through a jet pipe, sodium sulfide or pyrite is added into a hydrogen sulfide gas generator, the generated hydrogen sulfide gas and the primary demercuration solution generate continuous vulcanization reaction in the continuous vulcanization reaction device to generate mercuric sulfide precipitate and secondary demercuration purification solution, the secondary demercuration purification solution is adsorbed by a secondary purification solution adsorption tank to obtain tertiary demercuration purification solution, and the tertiary demercuration purification solution enters a hydrogen sulfide generator again to continue continuous vulcanization reaction. The mercury in any form in the high-acidity mercury-containing waste acid liquid can be continuously and efficiently removed by utilizing the diaphragm electrodeposition-continuous vulcanization-adsorption deep mercury removal method combined mercury removal device. The first demercuration rate is more than 90 percent, and the second demercuration rate is more than 99 percent. The mercury concentration of the waste acid modified liquid after deep demercuration treatment is lower than 0.03 mg/L. The combined demercuration device can directly and efficiently remove mercury in any form without adjusting the pH value, has high efficiency and no pollution, can realize the recovery of mercury resources, and is more favorable for the comprehensive utilization of acid liquor after purification.
The analysis of the original data of the high-acidity chemical mercury-containing waste liquid of different batches is shown in table 1:
TABLE 1 summary of the detection and analysis of the chemical sulfonation salting-out filtrate
Example 2:
taking No. 1 chemical sulfonation salting-out filtrate for experimental study, wherein the research process is as follows:
the first step, the step of membrane electrodeposition demercuration. The mercury concentration in the initial high-acidity chemical mercury-containing waste liquid is 11300mg/L, the acid concentration is 31.50%, a vertical diaphragm electrolytic cell is used, a diaphragm is a cation exchange membrane, a 10mm graphite polar plate is adopted as an anode, a 1mm stainless steel polar plate is adopted as a cathode, and the current density of the diaphragm electrodeposition cathode is 60A/m2The homopolar distance is 100mm, the additive thiourea is 0.5g/L, the electro-deposition time is 60min, the mercury concentration in the primary mercury removal liquid after deposition is 904mg/L, the mercury removal rate in the process is 92%, and the acid liquid is composed of CODCr9.55×104The mg/L is reduced to 3.6 × 104mg/L or less, as shown in Table 2.
And step two, continuously vulcanizing and removing mercury. The two jet pipes are hermetically arranged at inlets on two sides of the three-mouth flask, the hydrogen sulfide reactor is a conical flask with a sealed three-way, then the conical flask is sealed by a glass pipe sealing plug with a lead-out gas, the gas guide pipe is communicated with the silicon rubber pipe, the silicon rubber pipe is communicated with the glass pipe, finally the glass pipe is inserted into the conical flask filled with the sodium hydroxide solution, and the alkali liquor absorbs the redundant hydrogen sulfide gas. Acid liquor used in the hydrogen sulfide reaction is primary demercuration liquid, and a sulfur source is sodium sulfide sold in the market; preparing hydrogen sulfide gas according to a common laboratory conventional method, wherein the preparation of hydrogen sulfide is carried out according to the control that the molar ratio of S to Hg is 4.5, installing a stop valve at a hydrogen sulfide gas outlet, connecting the hydrogen sulfide gas to a gas inlet of a jet pipe through a hydrogen sulfide generator conduit, introducing the treated primary demercuration solution containing 904mg/L of mercury into a solution inlet of the jet pipe through a peristaltic pump conduit, continuously reacting for 2.0h, wherein the mercury concentration in the treated acid solution is 18mg/L, and the continuous vulcanization demercuration in the process is 98.01 percent as shown in Table 3:
and step three, adsorbing and removing mercury. The secondary purification liquid enters an adsorption column connected in series in three stages, adsorbents filled in the bottom layer and the middle layer of the first and second stages of adsorption columns are commercially available acid-resistant special mercury adsorption materials, and modified bentonite is filled in the upper layer. The two stages of the adsorption columns are connected in series and then connected in series with the sulfur-carrying activated carbon adsorption column, acid liquor enters the first-stage adsorption column through a peristaltic pump guide pipe and finally flows out of an outlet of the activated carbon adsorption column, the total retention time of the acid liquor in the adsorption column is 120-150 min, and finally, the mercury concentration of the solution subjected to adsorption deep demercuration is lower than 0.03mg/L through sampling analysis, as shown in Table 4.
Example 3
Taking No. 1 chemical sulfonation salting-out filtrate for experimental study, wherein the research process is as follows:
the first step, the step of membrane electrodeposition demercuration. The mercury concentration in the initial high-acidity chemical mercury-containing waste liquid is 11300mg/L, the acid concentration is 31.50%, a vertical diaphragm electrolytic cell is used, a diaphragm is a cation exchange membrane, a 10mm graphite polar plate is adopted as an anode, a 1mm stainless steel polar plate is adopted as a cathode, and the current density of the diaphragm electrodeposition cathode is 70A/m2The homopolar distance is 100mm, the additive thiourea is 0.6g/L, the electrodeposition time is 70min, the concentration of mercury in the primary mercury removal liquid after deposition is 904mg/L, the mercury removal rate in the process is 92%, and the primary mercury removal liquid is composed of CODCr9.55×104The mg/L is reduced to 3.6 × 104mg/L or less, as shown in Table 2.
And step two, continuously vulcanizing and removing mercury. The two jet pipes are hermetically arranged at inlets on two sides of the three-mouth flask, the hydrogen sulfide reactor is a conical flask with a sealed three-way, then the conical flask is sealed by a glass pipe sealing plug with a lead-out gas, the gas guide pipe is communicated with the silicon rubber pipe, the silicon rubber pipe is communicated with the glass pipe, finally the glass pipe is inserted into the conical flask filled with the sodium hydroxide solution, and the alkali liquor absorbs the redundant hydrogen sulfide gas. The acid liquor used in the hydrogen sulfide reaction is a primary demercuration liquid, the acid liquor is large in amount, and the sulfur source is commercially available ferric sulfide; preparing hydrogen sulfide gas according to a common laboratory conventional method, wherein the preparation of hydrogen sulfide is carried out according to the control that the molar ratio of S to Hg is 4.5, installing a stop valve at a hydrogen sulfide gas outlet, connecting the hydrogen sulfide gas to a gas inlet of a jet pipe through a hydrogen sulfide generator conduit, introducing the treated acid solution containing 904mg/L of mercury into the solution inlet of the jet pipe through a peristaltic pump conduit, continuously reacting for 2.5h, wherein the concentration of mercury in the treated acid solution is 18mg/L, and the continuous vulcanization demercuration in the process is 98.01 percent as shown in Table 3.
And step three, adsorbing and removing mercury. And an adsorption column is arranged in the secondary purified liquid adsorption tank, the adsorbents filled in the bottom layer and the middle layer of the adsorption column are commercially available acid-resistant special mercury adsorption materials, and the modified clay is filled in the upper layer. The two stages of the adsorption columns are connected in series and then connected in series with the modified active coke adsorption column, acid liquor enters the first-stage adsorption column through a peristaltic pump guide tube and finally flows out of an outlet of the active carbon adsorption column, the total retention time in the adsorption column is 130min, and finally, the mercury concentration of the solution subjected to adsorption deep demercuration is lower than 0.03mg/L through sampling analysis, as shown in Table 4.
TABLE 2 analysis summary of the mercury removal effect of vertical membrane electrodeposition in mg/L
Table 3 analytical summary units for continuous sulfidation demercuration effect: mg/L
Table 4 deep sorption effect analysis summary units: mg/L
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims (7)

1. A combined mercury removal device for high-acidity chemical mercury-containing waste liquid is characterized by at least comprising an acid pump (1, 4, 7, 20 and 22), a waste liquid storage tank (2), an electrolytic deposition tank (3), a simple substance mercury storage tank (5), a primary mercury removal liquid storage tank (6), a first jet pipe (8), a second jet pipe (9), a hydrogen sulfide generator (10), hydrogen sulfide gas conveying pipes (11, 13 and 19), a hydrogen sulfide storage tank (12), a continuous vulcanization reaction device (14), a mercury release stop valve (15), a slurry pump (16), a solid-liquid separator (17), a sludge receiving tank (18), a secondary purification liquid adsorption tank (21), a liquid outlet pipe (23) and a sludge release stop valve (24);
an upper inlet of the waste liquid storage tank (2) is connected with high-acidity high-mercury-content waste liquid, a lower outlet of the waste liquid storage tank (2) is communicated with a solution inlet of the diaphragm electrolytic deposition tank (3) through a pipeline, a bottom opening of the diaphragm electrolytic deposition tank (3) is connected with the elemental mercury storage tank (5) through a pipeline, and a side liquid outlet of the diaphragm electrolytic deposition tank (3) is connected with the primary demercuration liquid storage tank (6) through a pipeline;
the jet pipe (8) and the jet pipe (9) are hermetically arranged in the continuous vulcanization reaction device (14), the liquid outlet of the primary mercury removal liquid storage tank (6) is respectively connected with the solution inlet of the jet pipe (8) and the solution inlet of the jet pipe (9) through pipelines, the outlet at the bottom of the continuous vulcanization reaction device (14) is connected with the inlet of the solid-liquid separator (17) through an acid-resistant pipeline, and the lower end of the discharging flange of the solid-liquid separator (17) is provided with a sludge receiving tank (18); the outlet of the liquid receiving disc of the solid-liquid separator (17) is connected with an inlet of the secondary purified liquid adsorption tank (21) through a liquid pipeline;
the outlet of the secondary purified liquid adsorption tank (21) is connected with the liquid inlet of the hydrogen sulfide generator (10) through a pipeline, the other inlet of the secondary purified liquid adsorption tank (21) is connected with the liquid outlet of the continuous vulcanization reaction device (14), and the liquid outlet of the secondary purified liquid adsorption tank (21) is connected with the liquid outlet pipe (23).
2. The combined mercury removal device for the high-acidity chemical mercury-containing waste liquid as defined in claim 1, wherein a first acid-resistant pump (1) is installed on a communication pipeline between an upper inlet of the waste acid storage tank (2) and the high-acidity mercury-containing waste liquid, a second acid-resistant pump (4) is installed on a communication pipeline between the diaphragm electrowinning cell (3) and the waste acid storage tank (2), a third acid-resistant pump (7) is installed on a pipeline which is jointly communicated with the primary mercury removal liquid storage tank (6), the jet pipe (8) and the jet pipe (9), a slurry pump (16) is installed on a pipeline which is communicated with an outlet at the bottom of the continuous vulcanization reaction device (14) and the solid-liquid separator (17), and a fourth acid-resistant pump (20) is installed on a pipeline which is connected between the solid-liquid separator (17) and the secondary purified liquid adsorption tank (21).
3. The combined mercury removal device for the high-acidity chemical mercury-containing waste liquid as defined in claim 1, wherein a mercury release stop valve (15) is arranged on a communication pipeline between the lower outlet of the diaphragm electrowinning cell (3) and the elemental mercury storage tank (5).
4. The combined mercury removal device for the high-acidity chemical mercury-containing waste liquid as claimed in claim 1, wherein a gas booster pump (19) is arranged on a common communication pipeline of the hydrogen sulfide storage tank (12) and the air inlets of the first jet pipe (8) and the second jet pipe (9).
5. The combined mercury-removing device for the high-acidity chemical mercury-containing waste liquid as claimed in claim 1, wherein a gas stop valve and a pressure gauge are installed on a gas pipeline communicated between a gas outlet of the hydrogen sulfide generator (10) and an inlet of the hydrogen sulfide storage tank (12).
6. The method for jointly removing mercury from high-acidity chemical mercury-containing waste liquid is realized by adopting the device of claim 1, and is characterized by comprising the following steps of:
step 1, carrying out membrane electrodeposition demercuration, wherein the mercury concentration in the initial high-acidity chemical mercury-containing waste liquid is 8000-12000 mg/L, and the acid concentration is 30-35%; taking a graphite polar plate as an anode, a stainless steel polar plate as a cathode, a cation exchange membrane or a polyester cloth bag as a diaphragm, carrying out electrodeposition on the diaphragm, wherein the current density of the cathode is 50-100A/m 2, the same polar distance is 80-100 mm, the additive thiourea is 0.5-1 g/L, the electrodeposition time is 60-90 min, and obtaining electrolytic mercury and a primary mercury removal solution after deposition;
step 2, continuously carrying out sulfuration and demercuration, namely, carrying out hydrogen sulfide reaction by using high-acidity chemical mercury-containing waste liquid as acid liquid and one or more of sodium sulfide, iron sulfide and pyrite as a sulfur source, wherein the prepared hydrogen sulfide is controlled according to the molar ratio of S to Hg of 3-5; introducing hydrogen sulfide gas into a gas inlet of a jet pipe, introducing the primary demercuration liquid into a solution inlet of the jet pipe, continuously reacting for 2.0-3.0 h, and enabling the concentration of mercury in the treated secondary purification liquid to be lower than 20 mg/L;
and 3, deeply adsorbing and removing mercury, namely allowing the secondary purified liquid to enter a secondary purified liquid adsorption tank for adsorbing and removing mercury, wherein the adopted adsorbent is one or more of acid-resistant mercury adsorption material, modified bentonite, modified clay or sulfur-loaded activated carbon, modified activated coke and the like, and a tertiary purified liquid with mercuric sulfide precipitate and mercury concentration lower than 0.03mg/L is obtained after adsorption.
7. The method for jointly removing mercury from high-acidity chemical mercury-containing waste liquid as claimed in claim 6, wherein the adsorption and removal of mercury in step 3 is performed in a three-stage series connection manner, and the first-stage adsorption column and the second-stage adsorption column respectively comprise, from bottom to top: acid-resistant mercury adsorption materials are filled in the bottom layer and the middle layer, modified bentonite or modified clay is filled in the upper layer, and sulfur-loaded active carbon or modified active coke is filled in the third-level adsorption columns.
CN202010541284.0A 2020-06-15 2020-06-15 Method and device for joint demercuration of high-acidity chemical mercury-containing waste acid liquid Pending CN111762927A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113501594A (en) * 2021-07-09 2021-10-15 中南大学 Method for recovering mercury from high-mercury-content waste liquid

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113501594A (en) * 2021-07-09 2021-10-15 中南大学 Method for recovering mercury from high-mercury-content waste liquid
CN113501594B (en) * 2021-07-09 2022-04-19 中南大学 Method for recovering mercury from high-mercury-content waste liquid

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