CN105174393A - Method for treatment of mercury-containing wastewater by superconducting magnet magnetic field intensified sulfuration process - Google Patents

Abstract

A method for treating mercury-containing wastewater by means of a superconducting magnet magnetic field-enhanced vulcanization method, using a complete mixing reactor, adding metal sulfides to the mercury-containing wastewater, and applying a magnetic field around the complete mixing reactor to realize the separation of metal sulfides and mercury Rapid precipitation reaction to purify water quality. In the present invention, under the action of the strong magnetic field of the superconducting magnet, the conductivity of the solution increases, the potential decreases, the flocculation and sedimentation speed and the filtration speed of the sulfide slag are improved, and the utilization rate of the sulfide agent is improved. The method of the invention utilizes the superconducting magnet magnetic field enhanced vulcanization method to treat mercury-containing wastewater, and can be used for removing mercury pollutants in water bodies such as groundwater and industrial wastewater.

Description

A method of using superconducting magnet magnetic field enhanced vulcanization method to treat mercury-containing wastewater

technical field

The invention belongs to the technical field of water treatment, and relates to a mercury-containing treatment method for industrial waste water and underground drinking water, and more particularly relates to a method for treating mercury-containing waste water by means of a superconducting magnet magnetic field enhanced vulcanization method.

technical background

Among non-ferrous metals, mercury is rarer than antimony. The total reserve in the earth's crust is 1.6×10 ¹¹ t, but 99.98% is in a dispersed state and cannot be utilized, and only 0.02% is enriched in mineable deposits. Mercury China has large mercury reserves and is one of the main mercury-producing countries in the world. Mercury has the characteristics of large specificity (13.546), low melting point (-38.87°C), high boiling point (356.95°C), good electrical conductivity and uniform expansion coefficient, etc. , so that it is widely used in the fields of industry, agriculture, science and technology, transportation, medicine and health, and national defense. According to statistics, there are more than 80 kinds of industries in the world that use mercury as raw material, and there are more than 3,000 uses of mercury. With such a wide range of use, about 1.5-3.0×10 ⁴ t of mercury is lost to the environment globally every year, polluting the environment in three ways: waste gas, waste residue, and waste water, among which mercury-containing waste water is the most harmful. Mercury-containing wastewater mainly comes from chlor-alkali chemical plants (mercury method), non-ferrous metal smelters (flue gas washing), amalgam recovery of precious metals, pesticide plants (insecticides, fungicides, fungicides, seed selection agents, etc.), chemical Industry (catalyst), paper industry (bactericide, viscous agent and flocculation remover, etc.), electrical and electronic industry (connecting circuits, manufacturing switches, light bulbs and batteries, etc.), petrochemical and plastic industry (catalyst), measuring instruments, A certain amount of mercury-containing wastewater is also discharged from the production of thermometers and pressure gauges and the pharmaceutical (disinfectant, preservative, etc.) industry, as well as explosives, pharmaceuticals, printing and dyeing, cosmetics, photographic industries, scientific research institutions, and hospital laboratories.

The removal methods of mercury in wastewater mainly include chemical precipitation method, metal reduction method, activated carbon adsorption method, ion exchange method, filtration method, electrolysis method, wool absorption method, microbial method, etc. Among them, the chemical precipitation method is a very common mercury removal method, which is suitable for different concentrations and types of mercury salts, especially for industrial wastewater with a high concentration of mercury. The most commonly used precipitation method is the sulfide precipitation method. Under weakly alkaline conditions, mercury ions and sulfide ions have a strong affinity, and mercury sulfide with a very small solubility is formed and removed from the solution. However, the main problems of the traditional sulfide precipitation method for mercury removal are as follows:

1) The dosage of vulcanizing agent is high, the utilization rate of agent is low, and the mercury removal rate needs to be further improved. Generally, the amount of sulfide added needs to be 50% to 80% excessive according to theoretical calculations. Too much sulfide will not only reduce the utilization rate of chemicals, increase the cost of water treatment, but also cause secondary pollution of sulfur, and excessive sulfide ions will React with mercury sulfide to form water-soluble mercury-sulfur complexes to reduce the treatment effect;

2) The settling speed and filtration speed of sulfide slag are slow. The particle size of the produced mercury sulfide precipitate is very fine, and most of it is suspended in the wastewater or forms a dispersion, which is not easy to precipitate, resulting in a low mercury removal rate, which needs to be further improved. Moreover, the mercury sulfide slag has a high moisture content and is not easy to be removed by filtration.

Contents of the invention

The purpose of the present invention is to provide a method for treating mercury-containing wastewater by means of a superconducting magnet magnetic field-enhanced sulfidation method to solve the problems of high sulfide dosage, low mercury removal rate, settling velocity of sulfide slag and The filtration speed is slow, and the sediment moisture content is high.

In order to achieve the above object, the method for treating mercury-containing wastewater by superconducting magnet magnetic field enhanced vulcanization method provided by the present invention adopts the form of a complete mixing reactor, adding metal sulfides to the mercury-containing wastewater, and applying a magnetic field around the complete mixing reactor Realize the rapid precipitation reaction of metal sulfide and mercury to purify the water quality.

The method, wherein the applied magnetic field is a low-temperature superconducting magnetic field.

The method, wherein the magnetic field strength is >30.0mT.

The method, wherein the mercury-containing wastewater includes mercury-polluted industrial wastewater and groundwater.

The method, wherein the pH value of the mercury-containing wastewater is 6.5-13.5.

The method, wherein the metal sulfide is one or more sulfides of iron, copper, and magnesium. .

Compared with the prior art, the present invention has the following advantages:

1. Compared with the current mercury removal technology by sulfidation method, the present invention can improve the removal efficiency of mercury by sulfide, reduce the dosage of sulfide agent, and improve the utilization rate of sulfide agent.

2. The present invention broadens the mercury removal environment and application range of the sulfide precipitation method, and broadens the effective pH range of mercury removal by sulfide from weakly alkaline to weakly acidic to strongly alkaline.

Not only suitable for anaerobic environment but also suitable for aerobic environment; not only suitable for industrial wastewater, but also suitable for groundwater treatment;

3. Use the superconducting magnetic field to strengthen the sulfidation method to remove mercury. Using the magnetic field can reduce the binding force between water molecules, change the structure of the sulfide slag, and increase the particle size of the sulfide slag, thereby increasing the settling rate of the flocs, shortening the reaction settling time, and reducing the size of the sulfide slag. Reactor volume. At the same time, it can significantly improve the filtration performance of the filter residue and improve the dehydration performance of the residue.

4. The present invention is relatively simple to modify the existing fully mixed reactor for mercury removal by sulfide, and only needs to place it in a superconducting magnetic field. Advantages of using low-temperature superconducting magnetic field: the variable range of magnetic field strength is large, and the magnetic field strength can be adjusted according to actual needs; the space available for superconducting magnetic field is large, and it can be applied to large anaerobic reaction tanks; once the low-temperature superconducting magnetic field is started and operated at low temperature, The electric coil that generates the magnetic field operates in a superconducting state, and its resistance is zero, so the energy consumption is zero, and the extra operating cost for using the low-temperature superconducting magnetic field to strengthen the vulcanizing agent to remove mercury is low.

Detailed ways

The present invention is based on the principle that under the action of a strong magnetic field of a superconducting magnet, the conductivity of the solution increases, the potential decreases, and the flocculation and sedimentation speed of the sulfide slag and the filtration speed are improved, so as to improve the removal efficiency of sulfide to mercury, and at the same time reduce the The dosage of vulcanizing agent can improve the utilization rate of vulcanizing agent and increase the precipitation and filtration speed of vulcanizing slag. It can be used for the removal of mercury pollutants in industrial mercury-containing wastewater and groundwater.

The invention adopts the form of a completely mixed reactor, which is suitable for both anaerobic environment and aerobic environment, and not only suitable for ex-situ treatment, but also suitable for in-situ treatment.

In the present invention, a certain amount of sulfide is added to the mercury-containing wastewater, and a superconducting magnetic field is applied around the reactor to realize the rapid precipitation reaction of sulfide and mercury so that the water quality is purified. The mercury-containing wastewater of the present invention mainly includes mercury-polluted industrial wastewater and groundwater.

In the method of the present invention, the selected condition is:

The magnetic field is a low-temperature superconducting magnetic field, the magnetic field strength is >30.0mT, the pH value of the mercury-containing wastewater is 6.5-13.5, and the metal sulfide is one or more of iron, copper, and magnesium. In the fully mixed reactor, the reaction time of mercury-containing wastewater and metal sulfide is 0.25-4h.

Embodiment one

In this embodiment, in a fully mixed reactor, 0.5 g/L iron sulfide is added to 50 mg/L (calculated as Hg) of mercury-containing water, pH=6.5, and the magnetic field used is a superconducting magnet magnetic field, and the magnetic field strength is about 3T . Under the condition of magnetic field, iron sulfide can remove 93% of mercury within 1.0h. However, in the absence of a magnetic field, only 80% of mercury can be removed even after 1.5 hours of reaction. In the presence of a superconducting magnetic field, the conductivity of the solution increases by 22%, and the potential decreases by 12%. After being treated by the superconducting magnetic field, the filtration speed of mercury sulfide waste liquid is increased by 38%.

Embodiment two

In this embodiment, in a fully mixed reactor, 0.5 g/L copper sulfide is added to 40 mg/L (calculated as Hg) of mercury-containing water, pH=8.5, the magnetic field used is a superconducting magnet magnetic field, and the magnetic field strength is about 5T . Under the condition of magnetic field, iron sulfide can remove 96% of mercury within 0.5h. In the absence of a magnetic field, only 85% of mercury can be removed even after 1.5 hours of reaction. In the presence of a superconducting magnetic field, the conductivity of the solution increases by 27%, and the potential decreases by 15%. After being treated by the superconducting magnetic field, the filtration speed of mercury sulfide waste liquid is increased by 38%.

Claims (6)

1. one kind utilizes the method for superconducting magnet magnetic field-intensification sulfuration method process mercury-containing waste water, adopt the form of complete, in mercury-containing waste water, add metallic sulfide, around complete, apply the rapid precipitation that magnetic field realizes metallic sulfide and mercury react thus water quality is purified.

2. method according to claim 1, wherein, the magnetic field of applying is low temperature superconducting field.

3. method according to claim 1 and 2, wherein, magneticstrength >30.0mT.

4. method according to claim 1, wherein, mercury-containing waste water comprises trade effluent and the underground water of mercury pollution.

5. the method according to claim 1 or 4, wherein, the pH value of mercury-containing waste water is 6.5-13.5.

6. method according to claim 1, wherein, metallic sulfide is one or more sulfide in iron, copper, magnesium.