Tailing wastewater organic matter photodegradation method based on activated pyrite and application

Abstract

The invention discloses a tailing wastewater organic matter photodegradation method based on activated pyrite and application, aims to obtain a simple, convenient, efficient and low-cost tailing wastewater treatment technology, and belongs to the technical field of mine wastewater treatment. The method comprises the following steps that firstly, pyrite is pretreated, and high-activity pyrite particles are obtained; then adding the active pyrite into the tailing wastewater, so that the pyrite and the tailing wastewater are fully and uniformly mixed before being discharged into a tailing pond, or directly and uniformly throwing the active pyrite into the tailing pond; and finally, utilizing sunlight in the environment to induce photocatalysis of the pyrite to remove organic matters. According to the method, the pyrite which is common in a sulfide ore area is used as a wastewater treatment material, reactive oxygen species (ROS) are generated through adsorption of the pyrite and natural light induction, the effect of removing organic matter in the tailing wastewater is remarkable, secondary pollution can be effectively reduced, and the method has a positive effect on sustainable development of the mining industry and environmental protection.

Description

Technical field:

[0001] The invention is applicable to the technical field of mine wastewater treatment, and specifically relates to a method for photodegrading organic matter in tailings wastewater based on active pyrite and its application. Background technology:

[0002] Flotation process is the most widely used and effective mineral processing technology at present. About 2 billion tons of minerals are processed by flotation every year. In this process, 4-7 tons of wastewater will be generated for processing one ton of ore, mainly residual flotation reagents and other organic pollutants, such as xanthate, sulfur nitrogen, sulfur aminoester and other collectors. Among them, butyl xanthate is the most widely used collector in the flotation process of sulfide minerals. Although it can be consumed by sulfide ores in concentrate wastewater and tailings wastewater, nearly half of the xanthate is still discharged and remains in the tailings pond. On the one hand, the discharge of tailings wastewater will produce toxic gases and unpleasant odors, posing a serious threat to human health and the ecosystem. On the other hand, if it is directly reused without effective treatment, the residual organic reagents will change the chemical properties of the pulp, thereby destroying the flotation selectivity and reducing the efficiency of mineral processing.

[0003] At present, the treatment technologies for organic agents in tailings wastewater are mainly divided into physical methods, chemical methods, and biological methods. However, most of these technologies have certain disadvantages. Physical adsorption technology has disadvantages such as low adsorption performance and difficulty in recovering adsorbents, resulting in high costs; biological methods usually take a long time and have low efficiency; chemical oxidation technology will increase COD in the water body and produce CS2 toxic gas; and a large amount of xanthate and heavy metals will remain in the precipitate of the coagulation-flocculation method, which is easy to cause secondary pollution. In view of this, exploring efficient and low-cost mineral processing wastewater treatment technologies is crucial for the sustainable development of the mining industry and environmental protection.

[0004] Pyrite is the most abundant sulfide mineral on the earth's surface. It is widely associated or coexisted with valuable metal ores such as copper, lead, and zinc. It is a common source of mine waste and acidic wastewater. It is generally believed that pyrite has rich functional groups and has good adsorption properties for organic matter. In addition, pyrite is a natural semiconductor mineral with a narrow band gap. It can be excited under natural light to produce electron-hole pairs and induce the production of reactive oxygen species (ROS) with strong oxidizing ability, which can degrade a variety of organic matter. Summary of the invention:

[0005] The present invention provides a method for photodegradation of organic matter in tailings wastewater based on active pyrite and its application. The method activates pyrite and uses its narrow bandgap semiconductor characteristics to induce the generation of reactive oxygen species (ROS) and other substances under the illumination of natural light, thereby reacting with organic agents in tailings wastewater to promote the degradation and removal of organic matter. The method can not only utilize the clean energy provided by sunlight, but also effectively reduce the toxic and harmful gas CS2 generated during the degradation of some organic matter such as xanthate, and can provide new ideas and solutions for the treatment of mining wastewater.

[0006] The invention proposes a tailings wastewater organic matter photodegradation method based on active pyrite and its application, the steps are: firstly, pre-treating the pyrite to obtain highly active pyrite particles; then adding the active pyrite particles into the tailings wastewater, so that the pyrite and the tailings wastewater are mixed before entering the tailings pond, or directly throwing the pyrite particles evenly into the tailings pond; finally, using the sunlight in the environment to induce the pyrite to catalyze the oxidation of the residual xanthate collector.

[0007] Furthermore, the pyrite is natural pyrite from a mine or artificially synthesized pyrite, and the pretreatment of the pyrite is crushing and grinding to obtain pyrite particles with a particle size of less than 0.5 mm.

[0008] Preferably, the ground pyrite particles can be added to an acidic solution for sufficient reaction to wash away the surface oxides, then rinsed with clean water until neutral, filtered and dried to obtain a highly active iron ore, wherein the acidic solution is a 0.1-2M hydrochloric acid or sulfuric acid solution.

[0009] Furthermore, the tailings wastewater is tailings slurry containing one or more xanthate flotation agents, sulfur-nitrogen flotation agents, and sulfur-aminoester flotation agents, or mineral processing wastewater discharged into a tailings pond.

[0010] Furthermore, the pyrite is added to the tailings wastewater discharged into the tailings pond by adding pyrite particles into the tailings sand bin and stirring, or directly adding the pyrite into the ore dressing wastewater to be discharged into the tailings pond.

[0011] Furthermore, the tailings sand bin is a sand bin used for dilution in a common tailings transportation process, or a newly built stirring tank before the tailings transportation pipe enters the tailings pond.

[0012] Furthermore, the method and application of photodegradation of organic matter in tailings wastewater based on active pyrite is characterized in that the throwing into the tailings pond is throwing into the sampling port or water accumulation area of ​​the tailings pond.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] 1. In the present invention, pyrite is a natural sulfide ore in the mining area, which has a wide source, low price, and strong adsorption affinity for organic agents. In addition, pyrite can produce reactive oxygen species (ROS) even in the absence of light.

[0015] 2. The pyrite used in the present invention is a narrow-bandgap semiconductor mineral that can induce the production of reactive oxygen species (ROS) under sunlight, and can enhance the degradation of organic matter in tailings wastewater through certain pretreatment. The operation is simple and the treatment cost is low.

[0016] 3. In the present invention, under the action of sunlight, pyrite has a high mineralization efficiency for organic matter in tailings wastewater, which can effectively reduce the generation of secondary pollutants.

[0017] 4. The reaction mainly occurs in the tailings pond, and no additional space is required. The sunlight used is a green and clean energy. During the oxidation and corrosion process of pyrite, the acid produced can neutralize the high alkalinity of common sulfide tailings ponds. It is a green and efficient method. Description of the drawings:

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some implementation examples of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 This is the removal effect of TOC in simulated wastewater by pyrite of different particle sizes under sunlight in the example.

[0020] Figure 2 To simulate the degradation process of tailings wastewater to produce CS2 under different conditions. Specific implementation method:

[0021] Now, various exemplary embodiments of the present invention are described in detail, and this detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present invention. It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention.

[0022] In addition, for the numerical range in the present invention, it is understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0023] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0024] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0025] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0026] Embodiment 1:

[0027] First, the pyrite was crushed, ground and sieved to prepare pyrite particles of different particle sizes of 74μm and 150μm, respectively. Then, they were washed with 1M hydrochloric acid and ultrapure water until neutral. After centrifugal separation, the obtained pyrite was placed in a freeze dryer at -40℃ for freeze drying; then three portions of 20mg / L butyl xanthate simulated tailings wastewater were prepared in an evaporating dish with a diameter of 150mm, and the pH was adjusted to 7; then, pyrite particles of different particle sizes were added to the corresponding simulated wastewater, and stirred evenly with a magnetic stirrer under sunlight for 6h. After pyrite was added to the control group, it was stirred with tin foil to avoid light. The average ultraviolet intensity was level 3, and samples were taken to measure the changes in the concentration of total organic carbon (TOC).

[0028] like Figure 1 As shown, after 12 hours of sunlight exposure, the removal rates of TOC in simulated wastewater by 74μm and 150μm pyrite reached 94.52% and 60.55%, respectively, while the removal rate of TOC in simulated wastewater by the dark reaction control group was 23.06%.

[0029] like Figure 2 As shown, adding acid to a single simulated wastewater promoted its degradation, and CS2 was detected in the degradation solution; after pyrite was added to the simulated wastewater, CS2 was detected during the reaction under dark reaction conditions, while no CS2 was detected during the entire process under light conditions, and no CS2 was detected in the pyrite eluate after the reaction.

[0030] The basic principles, main features and advantages of the present invention are shown and described above, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent substitutions or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method and application of photodegradation of organic matter in tailings wastewater based on active pyrite, characterized in that: The following steps are involved: First, the pyrite is pretreated to obtain highly active pyrite particles; then the active pyrite particles are added to the tailings wastewater to mix the pyrite and the tailings wastewater before entering the tailings pond. The active pyrite can also be directly and evenly sprinkled into the tailings pond; finally, the sunlight in the environment is used to induce the pyrite to catalyze the oxidation of residual organic matter in the tailings wastewater.

2. The method and application of photodegradation of organic matter in tailings wastewater based on active pyrite according to claim 1, characterized in that: The pyrite is natural pyrite or artificially synthesized pyrite, and the pretreatment of the pyrite is crushing and grinding to obtain pyrite particles with a particle size of less than 0.5 mm.

3. According to the method and application of photodegradation of organic matter in tailings wastewater based on active pyrite in claim 2, preferably, the ground pyrite particles can be added to an acidic solution for sufficient reaction, the surface oxides can be washed away, and then rinsed with clean water until neutral, filtered and dried to obtain active pyrite particles.

4. The method and application of photodegradation of organic matter in tailings wastewater based on active pyrite according to claim 2, characterized in that The acidic solution is a 0.1-2 M hydrochloric acid or sulfuric acid solution.

5. The method and application of photodegradation of organic matter in tailings wastewater based on active pyrite according to claim 1, characterized in that: The tailings wastewater is tailings slurry containing one or more xanthate flotation agents, sulfur-nitrogen flotation agents, and sulfur-aminoester flotation agents, or mineral processing wastewater discharged into a tailings pond.

6. The method and application of photodegradation of organic matter in tailings wastewater based on active pyrite according to claim 1, characterized in that: The pyrite particles are added into the tailings wastewater by adding the pyrite particles into the tailings sand bin and stirring, or directly adding the pyrite particles into the ore dressing wastewater discharged into the tailings pond.

7. The method and application of photodegradation of organic matter in tailings wastewater based on active pyrite according to claim 6, characterized in that: The tailings sand bin is a sand bin used for dilution in the common tailings transportation process, or a newly built stirring pool before the tailings transportation pipe enters the tailings pond.

8. The method and application of photodegradation of organic matter in tailings wastewater based on active pyrite according to claim 1, characterized in that: The method of throwing into the tailings pond is the sampling inlet of the tailings pond or the water accumulation place of the tailings pond.

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