Process and device for separating and recovering chromium and lead ions in wastewater

Abstract

The invention relates to the technical field of wastewater treatment, in particular to a process and device for separating and recycling chromium and lead ions in wastewater, the device comprises a flotation sedimentation tank provided with a water inlet pipe and a water outlet pipe, a feeding mechanism and a dispersing mechanism, the flotation sedimentation tank is used for containing wastewater to be treated, and the feeding mechanism is arranged in the flotation sedimentation tank; the feeding mechanism is connected with the flotation sedimentation tank and used for injecting reactants, collecting agents and aeration gas into the flotation sedimentation tank, and the dispersing mechanism is connected with the feeding mechanism and used for dispersing the reactants, the collecting agents and the aeration gas into the flotation sedimentation tank to make full contact with wastewater. The process comprises the following steps: introducing a reactant into the wastewater, so that chromium ions and lead ions respectively react to generate a chromium precipitate and a lead precipitate; a collecting agent is introduced into the wastewater, so that the lead precipitate is combined with the collecting agent to obtain hydrophobicity; aerating the wastewater to enable the lead precipitate to form floating foam; and separating and recovering the floating foam and the chromium precipitate. The method can realize synchronous separation and recovery of chromium and lead ions in wastewater, and is high in separation rate and recovery rate.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and more specifically, to a process and device for separating and recovering chromium and lead ions in wastewater. Background Art

[0002] Due to factors such as technical conditions, management mechanisms, and economic benefits, the development of mineral resources in China still faces severe ecological and environmental challenges. The high proportion of low-grade ores and relatively backward beneficiation and smelting technologies lead to the generation of a large amount of tailings and waste residues during the ore processing process. These waste materials not only occupy farmland and land resources, but the heavy metal elements they contain will also continuously migrate and diffuse into the surrounding environment through surface runoff, groundwater seepage, etc., and cause long-term harm to human health through the "soil-water-plant and animal" chain. Therefore, the remediation of soil heavy metal pollution and the treatment and resource utilization of heavy metal-containing wastewater around mines have attracted much attention and become increasingly important.

[0003] After years of sampling and experimental research, it has been found that chromium elements are generally associated with lead ore resources in China, such as crocoite. Therefore, the wastewater generated during the mining process (or the leachate of the surrounding soil) generally contains relatively high concentrations of lead ions (Pb 2+ ), and chromium ions (Cr 3+ ). Both of these heavy metal ions have strong biological toxicity and can accumulate in the human body through the food chain, causing serious health problems such as damage to the nervous system and decline in organ function. Therefore, mine wastewater containing these two heavy metal ions, the leachate of the surrounding soil, and even the surrounding soil containing these two heavy metals need to be treated accordingly to reduce heavy metal pollution. During the removal of soil heavy metal pollution, the soil is often pickled, so that the heavy metals in the soil are acidified into heavy metal ions and enter the liquid, generating wastewater containing relatively high concentrations of lead ions (Pb 2+ ), and chromium ions (Cr 3+ ).

[0004] Currently, for the treatment process of heavy metal-containing wastewater commonly used in industry, the first method is to carry out chemical precipitation one by one according to the physical and chemical characteristics of different heavy metals, then carry out solid-liquid separation, and finally carry out reduction to recover heavy metal elements or utilizable compounds. The second method is to mix the wastewater with an alkaline solution to obtain hydroxide precipitates of various metals mixed together, carry out solid-liquid separation, and through multiple separations, obtain the hydroxide of a certain heavy metal, and then carry out reduction to recover heavy metal elements or utilizable compounds. Among them, the first method requires setting multiple process flows and reactors successively according to the characteristics of different heavy metals, with a complex process and high cost. The second method has great difficulty in separating the hydroxides of different heavy metals from the hydroxide precipitates of various metals mixed together, the purity of the separated heavy metals is relatively low, and the actual utilization rate is not high, which affects the large-scale industrial promotion. The above wastewater treatment process also has problems such as complex process, high cost, and low separation and recovery rate when treating wastewater containing high concentrations of lead ions and chromium ions. Summary of the Invention

[0005] To overcome the problems of complex process, high cost, and low separation and recovery rate in the separation and recovery process of chromium and lead ions in wastewater in the above-mentioned prior art, the first aspect of the present invention provides a process for separating and recovering chromium and lead ions in wastewater.

[0006] The second aspect of the present invention provides a device for separating and recovering chromium and lead ions in wastewater.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is: a process for separating and recovering chromium and lead ions in wastewater, comprising the following steps: S1: Introduce a reactant into the wastewater containing chromium ions and lead ions, so that the chromium ions and lead ions react respectively to produce chromium precipitates and lead precipitates; S2: Introduce a collector into the wastewater, so that the lead precipitates combine with the collector to obtain hydrophobicity; S3: Aerate the wastewater to form a foam from the hydrophobic lead precipitates obtained in step S2; S4: Separate and recover the foam in the wastewater from the chromium precipitates.

[0008] In the technical solution of the present invention, the inventor creatively proposes a new process for separating and recovering chromium and lead ions in wastewater based on the precipitation characteristics of heavy metal ions in wastewater and the accumulation of experimental experience. This solution realizes the synchronous separation and recovery of chromium and lead ions in wastewater by reacting lead ions to form precipitates and then collecting them as foam, and forming precipitates of chromium ions to sink and separate, with a simple process flow, low cost, and high separation and recovery rate.

[0009] Preferably, the reactant is hydrogen sulfide, and the collector is ammonium dibutyldithiophosphate.

[0010] In this solution, hydrogen sulfide is used as the reactant, which can react with chromium ions to form chromium sulfide precipitate and with lead ions to form lead sulfide precipitate. Ammonium dibutyldithiophosphate is used as the collector, which can combine with lead sulfide to produce black foamy scum that floats to the liquid surface. Chromium sulfide sinks to the bottom without being affected by the collector, so as to be separated and recovered.

[0011] The present invention provides a device for separating and recovering chromium and lead ions in wastewater, comprising: a flotation sedimentation tank provided with a water inlet pipe and a drain pipe, the flotation sedimentation tank being used to hold the wastewater to be treated; a feeding mechanism arranged in the flotation sedimentation tank for respectively injecting a reactant, a collector and aeration gas into the flotation sedimentation tank; a dispersion mechanism connected to the feeding mechanism for dispersing the reactant, the collector and the aeration gas in the flotation sedimentation tank to fully contact with the wastewater.

[0012] In this solution, the device is used to implement the above-mentioned process for separating and recovering chromium and lead ions in wastewater. The flotation sedimentation tank serves as a reaction vessel. The feeding mechanism feeds the reactant, the collector and the aeration gas in accordance with the process sequence respectively. The dispersion mechanism can promote the contact reaction of each reagent, improving the precipitation rate and separation rate.

[0013] Further, the feeding mechanism includes an air inlet pipe, a collector inlet liquid pipe and an inner through pipe. The inner through pipe has a first inner through inlet, a second inner through inlet and an inner through outlet. The air inlet pipe is communicated with the first inner through inlet, the collector inlet liquid pipe is communicated with the second inner through inlet, and the first inner through inlet is located above the second inner through inlet.

[0014] In this solution, the external reactant supply pipeline and the aeration pipeline are connected through the air inlet pipe to supply the reactant or the aeration gas into the flotation sedimentation tank according to requirements. The external collector supply pipeline is connected through the collector inlet liquid pipe to supply the collector to the flotation sedimentation tank. Since the first inner through inlet is arranged above the second inner through inlet, that is, the inlet of the reactant is located above the inlet of the collector, it can prevent the introduced collector from entering the air inlet pipe to pollute and corrode the air inlet pipe.

[0015] Further, the dispersion mechanism includes an outer through pipe and a plurality of blades. The outer through pipe is rotatably arranged in the flotation sedimentation tank, and each blade is distributed circumferentially along the outer through pipe and fixedly connected to the outer through pipe.

[0016] In this solution, the blades rotate to stir the wastewater in the flotation sedimentation tank to be mixed with the reactant, the collector and the aeration gas respectively, promoting the reaction and improving the precipitation rate and separation rate.

[0017] Furthermore, the dispersion mechanism also includes a diverter, the external pipe has an external inlet and an external outlet, the external inlet is connected to the internal outlet, the external pipe is rotatably connected to the lower end of the internal pipe, the diverter is connected to the external outlet, the paddle is a hollow structure and has a plurality of outflow holes, and each of the paddles is respectively connected to the diverter.

[0018] In this scheme, the inner through-tube is connected with the outer through-tube, and the outer through-tube is connected with each blade through a flow divider. The reactant, collector and aeration gas enter the outer through-tube from the inner through-tube, and then flow out from the outflow holes of each blade through the flow divider. Under the action of centrifugal force, the cyclone of the wastewater in the flotation sedimentation tank can be realized, and at the same time, the reactant and collector are evenly distributed in the wastewater containing chromium and lead ions. Under the action of the cyclone of the mixed liquid, the reaction time of the reactant and collector in the wastewater can be extended, the precipitation rate and collection rate of chromium and lead ions in the wastewater can be increased, and the reaction efficiency can be comprehensively improved.

[0019] Furthermore, it also includes a foam scraping mechanism, which includes a rotating ring and a plurality of foam scraping components. The rotating ring is rotatably connected to the upper end of the external pipe, and each of the foam scraping components is distributed along the circumference of the rotating ring and is hinged to the rotating ring. The foam scraping component is connected to a float, and the foam scraping component can deflect around the hinge between the horizontal direction and the vertical direction.

[0020] In this scheme, a scraper mechanism is used to rotate and scrape off the foam on the liquid surface of the flotation sedimentation tank for separation and collection. Since the scraper assembly is hinged on the rotating ring, when the device is in a non-working state, no wastewater is injected into the flotation sedimentation tank, and the scraper assembly is in a vertical state, on the one hand, it is convenient for staff to enter the flotation sedimentation tank for maintenance, and on the other hand, it can also reduce the shear stress generated by the gravity of the scraper mechanism when it is horizontal, thereby extending the service life of the scraper frame. Since the scraper assembly is connected with a float, when the device is in a working state, wastewater is injected into the flotation tank, and the scraper mechanism gradually floats up from the lower end of the vertical state to a horizontal state around the hinge, thereby realizing the normal function of scraping off foam.

[0021] Furthermore, the foam scraping assembly includes a foam scraping frame, a slide member, a positioning member and a lifting movable column, one end of the positioning member is fixedly connected to the rotating ring, the other end of the positioning member is rotatably connected to one end of the lifting movable column, the upper end of the slide member is fixedly connected to the rotating ring, one end of the foam scraping frame is movably connected to the slide member, and the middle part of the foam scraping frame is rotatably connected to the other end of the lifting movable column.

[0022] In this solution, the foam scraping frame is used to directly contact and scrape the floating foam. By setting the chute member, positioning member, and lifting movable column, on the one hand, it can limit the foam scraping frame, enabling the foam scraping frame to deflect within the corresponding range. On the other hand, it can also improve the structural strength of the foam scraping assembly, making it more stable and reliable during the process of rotating to scrape the floating foam.

[0023] Furthermore, a collection trough is provided at the top of the side wall of the flotation sedimentation tank. The bottom of the collection trough is arc-shaped, and a collecting pipe is connected to the bottom of the collection trough.

[0024] In this solution, by setting the collection trough, it is ensured that the lead sulfide floating foam is not easily splashed out, facilitating collection. The arc-shaped bottom of the collection trough can more easily discharge the collected lead sulfide floating foam from the collecting pipe. At the same time, it can also reduce the amount of adhesion to the wall and improve the collection rate.

[0025] Furthermore, a cross beam is fixedly connected to the top of the flotation sedimentation tank. A driving device is fixedly connected to the cross beam. The driving device is respectively in transmission connection with the outer through pipe and the rotating ring, and the outer through pipe and the rotating ring rotate in opposite directions.

[0026] In this solution, the cross beam can be used to install the driving device. The driving device drives the outer through pipe and the rotating ring to rotate in opposite directions, improving the collection efficiency of the lead sulfide foam. The swirling flow also plays a role in cleaning the pool wall and the funnel-shaped pool bottom, extending the service life of the equipment and improving economic benefits.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The process for separating and recovering chromium and lead ions in wastewater of the present invention creatively proposes a new process for separating and recovering chromium and lead ions in wastewater according to the precipitation characteristics of heavy metal ions in wastewater and the accumulation of experimental experience. By reacting lead ions to form precipitates and then forming floating foam for collection, and separating chromium ions by forming precipitates and sinking, the synchronous separation and recovery of chromium and lead ions in wastewater are realized. The process flow is simple and the cost is relatively low.

[0028] 2. The device for separating and recovering chromium and lead ions in wastewater of the present invention is used to implement the above process for separating and recovering chromium and lead ions in wastewater. The flotation sedimentation tank serves as a reaction container, and the feeding mechanism respectively feeds the reaction agent, collector, and aeration gas in accordance with the process sequence. The dispersion mechanism can promote the contact reaction of each reagent, improving the precipitation rate and separation rate.

[0029] 3. The device for separating and recovering chromium and lead ions in wastewater of the present invention can realize the swirling flow of the wastewater in the flotation sedimentation tank through the dispersion mechanism, making the reaction agent and collector evenly distributed in the wastewater containing chromium and lead ions. Under the action of the swirling flow of the mixed liquid, the reaction time of the reaction agent and collector in the wastewater can be extended, improving the precipitation rate and collection rate of chromium and lead ions in the wastewater, and comprehensively improving the reaction efficiency.

[0030] IV. The chromium and lead ion separation and recovery device of the present invention scrapes the foam on the liquid surface of the flotation sedimentation tank through a foam scraping mechanism, so as to facilitate separation and collection. The foam scraping assembly can change between a vertical state and a horizontal state along with the liquid level in the flotation sedimentation tank, which is convenient for workers to enter the flotation sedimentation tank for maintenance, and can also reduce the shear stress when the foam scraping mechanism is horizontal, and prolong the service life of the foam scraping frame.

[0031] V. The chromium and lead ion separation and recovery device of the present invention realizes that the foam scraping mechanism rotates in the opposite direction to the swirling direction of the wastewater in the flotation sedimentation tank through a transmission mechanism, improving the collection efficiency of lead sulfide foam. At the same time, the swirling of the wastewater in the tank will also concentrate the precipitated chromium sulfide at the precipitation concentration port and drain it into the drain pipe, improving the collection efficiency of chromium sulfide precipitation. The swirling also plays a role in cleaning the pool wall and the funnel-shaped bottom of the pool, which can prolong the service life of the equipment and improve economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is the overall structural schematic diagram of the chromium and lead ion separation and recovery device in the present invention in a non-working state; Figure 2 is Figure 1 the structural schematic diagram with the upper part of the flotation sedimentation tank removed.

[0033] Figure 3 is the enlarged sectional view at the collection tank and the collecting pipe of the flotation sedimentation tank; Figure 4 is the overall structural schematic diagram of the chromium and lead ion separation and recovery device in the present invention in a working state; Figure 5 is Figure 4 the enlarged view of the monitoring component of; Figure 6 is the partial structural schematic diagram of the chromium and lead ion separation and recovery device in a non-working state; Figure 7 is Figure 6 the partial structural schematic diagram with the cross beam and the components above it removed; Figure 8 is Figure 7 the enlarged view of the foam scraping mechanism of; Figure 9 is the enlarged sectional view at the float; Figure 10 is Figure 8 the structural schematic diagram with the transmission structure removed; Figure 11 is Figure 10 the structural schematic diagram from another perspective; Figure 12 is the structural schematic diagram of the dispersion mechanism; Figure 13 is an enlarged sectional view of the blade; Figure 14 is a schematic view of the overall structure of the device for separating and recovering chromium and lead ions in wastewater of the present invention from another angle when it is in working state; Figure 15 is Figure 14 an enlarged view of the foam scraping mechanism of; Figure 16 is Figure 15 a schematic view of the structure from another perspective; Figure 17 is Figure 14 an enlarged view of the float of; Figure 18 is an enlarged top view of the foam scraping mechanism.

[0034] In the drawings: 1, flotation sedimentation tank; 11, collection tank; 12, collecting pipe; 13, cross beam; 14, water inlet pipe; 15, sediment concentration port; 16, drain pipe; 2, feeding mechanism; 21, air inlet pipe; 22, collector inlet liquid pipe; 23, inner through pipe; 231, first inner through inlet; 232, second inner through inlet; 233, inner through outlet; 24, double pipe stabilizer; 3, dispersion mechanism; 31, outer through pipe; 311, outer through inlet; 312, outer through outlet; 32, blade; 321, outflow hole; 33, flow dividing member; 34, connecting bearing; 341, fixing column; 4, foam scraping mechanism; 41, rotating ring; 411, supporting column; 42, foam scraping assembly; 421, foam scraping frame; 422, chute member; 423, positioning member; 424, lifting movable column; 425, roller; 43, float; 5, driving device; 51, output shaft; 52, inclined strut; 6, transmission structure; 61, first driving gear; 62, first driven gear; 63, second driving gear; 64, second driven gear; 7, monitoring assembly; 71, monitoring pipe; 72, monitoring tank; 73, monitoring fixing bolt. Detailed implementation manners

[0035] The drawings are only for illustrative purposes and should not be construed as a limitation of this patent; for better explaining this embodiment, some components in the drawings will be omitted, enlarged or reduced, and do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. The positional relationships described in the drawings are only for illustrative purposes and should not be construed as a limitation of this patent.

[0036] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "long", "short", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the accompanying drawings. This is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the accompanying drawings are only for illustrative purposes and should not be construed as a limitation of this patent. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0037] The technical solution of the present invention will be further specifically described below through specific embodiments and in conjunction with the accompanying drawings: Embodiment 1 This embodiment discloses a process for separating and recovering chromium and lead ions from wastewater, including the following steps: S1: Introduce a reactant into the wastewater containing chromium ions and lead ions to cause the chromium ions and lead ions to react separately to produce chromium precipitates and lead precipitates; S2: Introduce a collector into the wastewater to make the lead precipitate combine with the collector to obtain hydrophobicity; S3: Aerate the wastewater to cause the hydrophobic lead precipitate obtained in step S2 to form a foam; S4: Separate and recover the foam in the wastewater from the chromium precipitate.

[0038] In this embodiment, according to the precipitation characteristics of heavy metal ions in wastewater and the accumulation of experimental experience, a new process for separating and recovering chromium and lead ions from wastewater is creatively proposed. In this solution, the lead ions are reacted to form a precipitate and then form a foam for collection, and the chromium ions form a precipitate and sink for separation, so as to realize the synchronous separation and recovery of chromium and lead ions in wastewater. The process flow is simple and the cost is relatively low.

[0039] Taking the wastewater containing trivalent chromium ions and divalent lead ions as an example in this embodiment, the reactant is hydrogen sulfide. After hydrogen sulfide gas dissolves in water, it can react with trivalent chromium ions to form chromium sulfide precipitate and with divalent lead ions to form lead sulfide precipitate. After the precipitate is formed, a collector for lead sulfide, which is butyl ammonium xanthate, that is, ammonium dibutyl dithiophosphate (C4H9)2PSSNH4, is added to the wastewater. It can make the surface of lead sulfide obtain hydrophobicity, and by aerating the wastewater, the lead sulfide precipitate forms a black foam and floats to the liquid surface. The chromium sulfide precipitate is basically not affected by the collector, and the relative molecular mass of chromium sulfide (200.18) is relatively large, so it will precipitate downward. Through the process of this embodiment, the chromium ions and lead ions in the wastewater can be separated for recovery, which can provide conditions for the further resource utilization of heavy metals and improve economic benefits.

[0040] Example 2 As Figures 1 to 18 shown, this embodiment provides a device for separating and recovering chromium and lead ions in wastewater, which is used to implement the process of separating and recovering chromium and lead ions in wastewater in Example 1. Referring to Figure 1 and Figure 2 , the device of this embodiment includes a flotation sedimentation tank 1 provided with a water inlet pipe 14 and a drain pipe 16, a feeding mechanism 2, and a dispersing mechanism 3. The flotation sedimentation tank 1 is used to hold the wastewater to be treated. The feeding mechanism 2 is arranged in the flotation sedimentation tank 1 and is used to inject a reactant, a collector, and aeration gas into the flotation sedimentation tank 1 respectively. The dispersing mechanism 3 is connected to the feeding mechanism 2 and is used to disperse the reactant, the collector, and the aeration gas in the flotation sedimentation tank 1 to fully contact with the wastewater.

[0041] In this embodiment, the flotation sedimentation tank 1 serves as a reaction vessel that can hold wastewater and is used for carrying out reactions. The bottom of the flotation sedimentation tank 1 is funnel-shaped and slopes downward. A sedimentation concentration port 15 is provided at the center of the bottom of the flotation sedimentation tank 1. The drain pipe 16 is connected to the sedimentation concentration port 15, and a valve is arranged on the drain pipe 16. After the reaction is completed, water is drained through the drain pipe 16, and then filtration is carried out to obtain chromium precipitates, so as to enter the subsequent resource treatment process. The feeding mechanism 2 is used to introduce the reactant, the collector, and the aeration gas respectively according to the process sequence in Example 1. The dispersing mechanism 3 can promote the contact reaction of each reagent and improve the precipitation rate and separation rate.

[0042] The device for separating and recovering chromium and lead ions in wastewater in this embodiment can realize the synchronous precipitation, separation, and collection of trivalent chromium ions and divalent lead ions in heavy metal wastewater, and at the same time has a high precipitation rate and separation rate.

[0043] Referring to Figure 1 , Figure 6 and Figure 7 , the feeding mechanism 2 includes an air inlet pipe 21, a collector inlet liquid pipe 22, and an inner through pipe 23. The inner through pipe 23 has a first inner through inlet 231, a second inner through inlet 232, and an inner through outlet 233. The air inlet pipe 21 is connected to the first inner through inlet 231, and the collector inlet liquid pipe 22 is connected to the second inner through inlet 232. The first inner through inlet 231 is located above the second inner through inlet 232.

[0044] In this solution, the external reactant supply pipeline and the aeration pipeline are connected through the air inlet pipe 21, and the reactant or the aeration gas is supplied into the flotation sedimentation tank 1 according to requirements. The external collector supply pipeline is connected through the collector inlet liquid pipe 22 to supply the collector to the flotation sedimentation tank 1. Since the first inner through inlet 231 is arranged above the second inner through inlet 232, that is, the inlet of the reactant is located above the inlet of the collector, it can prevent the introduced collector from entering the air inlet pipe 21 to pollute and corrode the air inlet pipe 21.

[0045] Specifically, referring to Figure 1 , a cross beam 13 is fixedly connected to the top of the flotation sedimentation tank 1, and the feeding mechanism 2 is fixedly connected to the cross beam 13. A double-tube stabilizer bolt 24 is fixedly connected to the cross beam 13. The double-tube stabilizer bolt 24 has two through ports arranged vertically, and the air inlet pipe 21 and the collector liquid inlet pipe 22 respectively pass through the two through ports and are fixedly connected. On the one hand, the double-tube stabilizer bolt 24 can fixedly connect the air inlet pipe 21 and the collector liquid inlet pipe 22 to the cross beam 13, and on the other hand, it can make the two perpendicular and juxtaposed, reducing the horizontal space occupation on the cross beam 13.

[0046] In this embodiment, the inner through outlet 233 of the inner through pipe 23 is directly or indirectly communicated with the bottom of the flotation sedimentation tank 1, so as to inject the reactant, collector and aeration gas into the flotation sedimentation tank 1 from the bottom, promoting full reaction with the wastewater. Valves are provided on both the air inlet pipe 21 and the collector liquid inlet pipe 22 for opening and closing the pipeline. Among them, the air inlet pipe 21 can be respectively connected to the external reactant supply pipeline and the aeration pipeline, and the reactant or aeration gas can be communicated and supplied according to the process requirements.

[0047] Referring to Figure 2 , the dispersion mechanism 3 includes an outer through pipe 31 and a plurality of blades 32. The outer through pipe 31 is rotatably arranged in the flotation sedimentation tank 1, and each blade 32 is circumferentially distributed along the outer through pipe 31 and fixedly connected to the outer through pipe 31. The blades 32 rotate to stir the wastewater in the flotation sedimentation tank 1 to be mixed with the reactant, collector and aeration gas respectively, promoting the reaction and improving the precipitation rate and separation rate.

[0048] In some embodiments, the lower end of the inner through pipe 23 is connected to the upper end of the outer through pipe 31 and extends to the bottom of the flotation sedimentation tank 1, capable of transporting the reactant, collector and aeration gas to the bottom of the flotation sedimentation tank 1. The outer through pipe 31 and the inner through pipe 23 are rotationally connected through a bearing. The outer through pipe 31 can rotate around the vertical axis under the action of an external driving device 5, driving the blades 32 to rotate and stir the wastewater, generating a swirl to promote the reaction.

[0049] It can be understood that since the density of hydrogen sulfide gas (relative molecular mass 34.08) is greater than that of air (relative molecular mass about 29), when hydrogen sulfide gas is introduced, the hydrogen sulfide gas will pass downward into the outer through pipe 31 at the inner through pipe 23 and will not escape from the connection between the inner through pipe 23 and the outer through pipe 31. In some other embodiments, a movable sealing structure can also be added at the connection between the inner through pipe 23 and the outer through pipe 31 to prevent gas leakage.

[0050] In this embodiment, referring to Figure 12 , Figure 13 and Figure 7, the dispersion mechanism 3 further includes a flow splitter 33. The outer communication pipe 31 has an outer communication inlet 311 and an outer communication outlet 312. The outer communication inlet 311 is communicated with the inner communication outlet 233. The outer communication pipe 31 is rotatably connected to the lower end of the inner communication pipe 23. The flow splitter 33 is communicated with the outer communication outlet 312. The blade 32 is of a hollow structure and is provided with a plurality of outer flow holes 321. Each blade 32 is respectively communicated with the flow splitter 33.

[0051] In this embodiment, the outer communication inlet 311 is arranged at the upper end of the outer communication pipe 31, the outer communication outlet 312 is arranged at the lower end of the outer communication pipe 31, the lower end of the inner communication pipe 23 is communicated with the upper end of the outer communication pipe 31, and the lower end of the outer communication pipe 31 is communicated with each blade 32 through the flow splitter 33. The reactant, the collector, and the aeration gas enter the outer communication pipe 31 from the inner communication pipe 23, and then flow out from the outer flow holes 321 of each blade 32 through the flow splitter 33. Under the action of centrifugal force, the swirling of the wastewater in the flotation sedimentation tank 1 can be realized. At the same time, the reactant and the collector are evenly distributed in the wastewater containing chromium and lead ions. Under the action of the swirling of the mixed liquid, the reaction time of the reactant and the collector in the wastewater can be prolonged, the precipitation rate and the collection rate of chromium and lead ions in the wastewater can be improved, and the reaction efficiency can be comprehensively improved.

[0052] Reference Figure 12 And Figure 7 , the flow splitter 33 is in a substantially cubic shape, and its interior is of a hollow structure. The front side of the flow splitter 33 is hidden in the figure. The top of the flow splitter 33 is communicated with the lower end of the outer communication pipe 31, and the blades 32 are respectively connected to the four sides of the flow splitter 33. The outer communication pipe 31, the flow splitter 33, and the blades 32 are communicated in sequence, so that the reactant, the collector, and the aeration gas can enter the interior of the blades 32 and flow out from the outer flow holes 321. Each outer flow hole 321 is evenly distributed at the bottom of the blade 32. The reactant, the collector, and the aeration gas are evenly dispersed into the flotation sedimentation tank 1 as the blade 32 rotates, and are in full contact with the wastewater, so that a high precipitation rate and separation rate can be achieved.

[0053] Reference Figure 1 And Figure 3 , a collection tank 11 is provided at the top of the side wall of the flotation sedimentation tank 1. The bottom of the collection tank 11 is arc-shaped. A collecting pipe 12 is connected to the bottom of the collection tank 11, and a valve is arranged on the collecting pipe 12. In this embodiment, by providing the collection tank 11, it is ensured that the lead sulfide foam is not easily splashed out, so as to facilitate collection. The arc-shaped bottom of the collection tank 11 can more easily discharge the collected lead sulfide foam from the collecting pipe 12, and at the same time, it can also reduce the amount of adhesion to the wall and improve the collection rate.

[0054] Specifically, the collection tank 11 is in a "U" shape with an upward opening. The side of the collection tank 11 facing the inside of the flotation sedimentation tank 1 is the inner side, and the opposite is the outer side. The upper end of the side wall of the collection tank 11 on the outer side has a curvature and is inclined upward and inward and is higher than the height of the pool wall of the flotation sedimentation tank 1, which can prevent the lead sulfide foam from splashing out easily, thus ensuring the collection volume.

[0055] Reference Figure 1 And Figures 6 to 8 , a driving device 5 is fixedly connected to the cross beam 13 at the top of the flotation sedimentation tank 1. The driving device 5 is in transmission connection with the outer through pipe 31. The inner through pipe 23 is rotatably connected to the outer through pipe 31 through a bearing and is fixedly connected to the cross beam 13. The driving device 5 can be a driving motor, and the driving motor is fixedly connected above the cross beam 13 through a diagonal brace 52. The upper end of the outer through pipe 31 is rotatably connected to the cross beam 13 through an adapter bearing 34. The inner ring of the adapter bearing 34 is fixedly connected to the outer through pipe 31, and the outer ring of the adapter bearing 34 is fixedly connected to the cross beam 13 through a fixed column 341.

[0056] In this solution, the cross beam 13 is used to fixedly install the driving device 5 and the inner through pipe 23. The driving device 5 drives the outer through pipe 31 to rotate, stirring the wastewater to generate a swirl. The swirl can promote the reaction, and also play a role in cleaning the pool wall and the funnel-shaped pool bottom, prolonging the service life of the equipment and improving economic benefits.

[0057] Reference Figures 6 to 8 , the driving device 5 and the outer through pipe 31 are connected through a transmission structure 6. The transmission structure 6 at least includes a first driving gear 61 and a first driven gear 62. The first driving gear 61 is coaxially and fixedly connected to the output shaft 51 of the driving device 5. The first driven gear 62 is coaxially and fixedly connected to the outer through pipe 31. The first driving gear 61 meshes with the first driven gear 62, and the outer through pipe 31 is driven to rotate by the first driving gear 61 and the first driven gear 62.

[0058] Reference Figure 4 And Figure 5 , the water inlet pipe 14 is connected to the left side of the flotation sedimentation tank 1, and a water inlet valve is provided on the water inlet pipe 14. A monitoring component 7 is provided at the lower right part of the flotation sedimentation tank 1. The monitoring component 7 includes a monitoring pipe 71, a monitoring pool 72 and a monitoring fixing bolt 73. One end of the monitoring pipe 71 is communicated with the flotation sedimentation tank 1, the other end of the monitoring pipe 71 is connected to the monitoring pool 72, one end of the monitoring fixing bolt 73 is fixedly connected to the outer side wall of the flotation sedimentation tank 1, the monitoring pool 72 is fixedly connected in the monitoring fixing bolt 73, and a valve is provided on the monitoring pipe 71. The detection pool can be used for sampling for experiments to measure the ion concentration in the wastewater. If it is reduced to a certain ion concentration, then drainage and filtration separation can be carried out to enter the subsequent resource treatment process to ensure the precipitation rate of chromium and lead ions.

[0059] Embodiment 3 As Figures 1 to 18 shown, this embodiment is similar to Embodiment 2, the difference being that referring to Figure 4 and Figure 6 , the device for separating and recovering chromium and lead ions in the wastewater of this embodiment further includes a foam scraping mechanism 4. The foam scraping mechanism 4 includes a rotating ring 41 and a plurality of foam scraping components 42. The rotating ring 41 is rotatably connected to the upper end of the outer through pipe 31. Each foam scraping component 42 is circumferentially distributed along the rotating ring 41 and is hinged to the rotating ring 41. The foam scraping component 42 is connected with a float 43, and the foam scraping component 42 can deflect around the hinge between the horizontal direction and the vertical direction. The rotating ring 41 is rotatably connected to the outer through pipe 31 through a bearing. The float 43 is connected to a position of the foam scraping component 42 far from the rotating ring 41, which can be the middle or the end. The additional buoyancy provided by the float 43 is greater than the self-gravity of the foam scraping component 42, so the float 43 can drive the foam scraping component 42 to deflect and float upward.

[0060] In this embodiment, the foam scraping mechanism 4 is used to rotate and scrape the foam on the liquid surface of the flotation sedimentation tank 1 for easy separation and collection. Since the foam scraping component 42 is hinged to the rotating ring 41 and can deflect around the hinge between the horizontal direction and the vertical direction, referring to Figure 1 and Figure 6 , when the device is in a non-working state and no wastewater is injected into the flotation sedimentation tank 1, the foam scraping component 42 is in a vertical state. On the one hand, it is convenient for workers to enter the flotation sedimentation tank 1 for maintenance. On the other hand, it can also reduce the shear stress generated by the self-gravity of the foam scraping mechanism 4 when it is horizontal and extend the service life of the foam scraping frame 421. Since the foam scraping component 42 is connected with a float 43 and wastewater is injected into the flotation tank, referring to Figure 4 , when the device is in a working state, the foam scraping mechanism 4 gradually floats from the vertical state at the lower end to the horizontal state around the hinge to realize the normal function of scraping foam.

[0061] Referring to Figures 6 to 18 , the foam scraping component 42 includes a foam scraping frame 421, a chute member 422, a positioning member 423 and a lifting movable column 424. One end of the positioning member 423 is fixedly connected to the rotating ring 41, the other end of the positioning member 423 is rotatably connected to one end of the lifting movable column 424, the upper end of the chute member 422 is fixedly connected to the rotating ring 41, one end of the foam scraping frame 421 is movably connected in the chute member 422, and the middle part of the foam scraping frame 421 is rotatably connected to the other end of the lifting movable column 424.

[0062] In this embodiment, the foam scraping frame 421 is used to directly contact and scrape the foam. By setting the chute member 422, the positioning member 423 and the lifting movable column 424, on the one hand, it can limit the foam scraping frame 421 so that the foam scraping frame 421 deflects within the corresponding range. On the other hand, it can also improve the structural strength of the foam scraping component 42 and be more stable and reliable during the process of rotating and scraping the foam.

[0063] More specifically, refer to Figures 6 to 8 as well as Figure 11 , Figure 15 and Figure 18 , the positioning member 423 is grooved on one side away from the rotating ring 41, and a horizontally arranged shaft is fixedly connected in the groove, and a sleeve is provided at the upper end of the lifting movable column 424 and is connected to the shaft for rotation through a bearing. The middle part of the foam scraping frame 421 is also fixedly connected to a horizontally arranged shaft, and a sleeve is provided at the lower end of the lifting movable column 424 and is connected to the shaft for rotation through a bearing. The upper end of the slide member 422 is fixedly connected to the rotating ring 41, and the slide member 422 extends in the vertical direction. The upper end of the foam scraping plate is connected to a roller 425 through a shaft and a bearing, and is rollingly connected in the slide member 422 through the roller 425. Reference Figure 15 When the foam scraping frame 421 is horizontally arranged and in working state, a triangular structure is formed between the slide groove member 422, the lifting movable column 424 and the foam scraping frame 421, which has high stability during the working process.

[0064] refer to Figure 1 as well as Figures 6 to 8 The driving device 5 is respectively connected to the outer tube 31 and the rotating ring 41 in transmission, and the rotation directions of the outer tube 31 and the rotating ring 41 are opposite.

[0065] In this solution, the crossbeam 13 is used to fix the driving device 5, which drives the outer tube 31 and the rotating ring 41 to rotate in opposite directions, thereby improving the collection efficiency of lead sulfide foam. The vortex also plays a role in cleaning the pool wall and the funnel-shaped pool bottom, extending the service life of the equipment and improving the economic benefits.

[0066] refer to Figures 6 to 8, the driving device 5 is connected to the outer communication pipe 31 and the rotating ring 41 through a transmission structure 6. The transmission structure 6 includes a first driving gear 61, a first driven gear 62, a second driving gear 63 and a second driven gear 64. The first driving gear 61 and the second driving gear 63 are both coaxially and fixedly connected to the output shaft 51 of the driving device 5. The first driven gear 62 is coaxially and fixedly connected to the outer communication pipe 31. The first driving gear 61 meshes with the first driven gear 62, and the outer communication pipe 31 is driven to rotate by the first driving gear 61 and the first driven gear 62. The second driven gear 64 is coaxially and fixedly connected to the rotating ring 41 through a support column 411. The second driving gear 63 meshes with the second driven gear 64, and the rotating ring 41 is driven to rotate by the second driving gear 63 and the second driven gear 64. Since both the first driving gear 61 and the first driven gear 62 are external gears and are driven by external engagement, the rotation directions of the first driving gear 61 and the first driven gear 62 are opposite. The second driving gear 63 is an external gear, and the second driven gear 64 is an inner ring gear. The second driving gear 63 and the second driven gear 64 are in embedded engagement, so the rotation directions of the second driving gear 63 and the second driven gear 64 are the same. Also, since the first driving gear 61 and the second driving gear 63 are coaxially and fixedly rotated in the same direction, the rotation directions of the first driven gear 62 and the second driven gear 64 are opposite, so the rotation direction of the outer communication pipe 31 is opposite to the rotation direction of the rotating ring 41.

[0067] In this embodiment, the radii of the first driving gear 61, the first driven gear 62, the second driving gear 63 and the second driven gear 64 are different. By setting different gear radius ratios, the outer communication pipe 31 and the rotating ring 41 have different rotation speeds. For example, when the first driving gear 61 and the second driving gear 63 rotate one circle, the outer communication pipe 31 rotates one circle, while the rotating ring 41 rotates 0.12 circles. Therefore, the rotation speed of the outer communication pipe 31 is 8.3 times that of the rotating ring 41, so that the rotation speed of the blade 32 is 8.3 times that of the foam scraping mechanism 4. The swirling direction of the liquid in the pool is the same as the rotation direction of the blade 32. While ensuring the stirring effect of the blade 32, since the rotation direction of the foam scraping mechanism 4 is opposite to the rotation direction of the blade 32, the collection efficiency of lead sulfide floating foam can be improved.

[0068] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, and are not limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. Any modifications, equivalent replacements and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A process for separating and recovering chromium and lead ions from wastewater, characterized in that: It includes the following steps: S1: Introduce a reactant into the wastewater containing chromium ions and lead ions, so that the chromium ions and lead ions react respectively to produce chromium precipitates and lead precipitates; S2: Introduce a collector into the wastewater, so that the lead precipitates combine with the collector to obtain hydrophobicity; S3: Aerate the wastewater, so that the hydrophobic lead precipitates obtained in step S2 form a foam; S4: Separate and recover the foam in the wastewater from the chromium precipitates.

2. The chromium and lead ion separation and recovery process from wastewater according to claim 1, characterized in that: The reactant is hydrogen sulfide, and the collector is ammonium dibutyldithiophosphate.

3. A device for separating and recovering chromium and lead ions in wastewater, characterized in that: It includes: A flotation sedimentation tank (1) provided with a water inlet pipe (14) and a drain pipe (16), and the flotation sedimentation tank (1) is used to accommodate the wastewater to be treated; A feeding mechanism (2), and the feeding mechanism (2) is arranged in the flotation sedimentation tank (1) and is used to inject a reactant, a collector and an aeration gas into the flotation sedimentation tank (1) respectively; A dispersion mechanism (3), and the dispersion mechanism (3) is connected to the feeding mechanism (2) and is used to disperse the reactant, the collector and the aeration gas in the flotation sedimentation tank (1) to fully contact with the wastewater.

4. The device for separating and recovering chromium and lead ions in wastewater according to claim 3, characterized in that: The feeding mechanism (2) includes an air inlet pipe (21), a collector liquid inlet pipe (22) and an inner through pipe (23). The inner through pipe (23) has a first inner through inlet (231), a second inner through inlet (232) and an inner through outlet (233). The air inlet pipe (21) is communicated with the first inner through inlet (231), the collector liquid inlet pipe (22) is communicated with the second inner through inlet (232), and the first inner through inlet (231) is located above the second inner through inlet (232).

5. The chromium and lead ion separation and recovery device for wastewater according to claim 4, characterized in that: The dispersion mechanism (3) includes an outer through pipe (31) and a plurality of blades (32). The outer through pipe (31) is rotatably arranged in the flotation sedimentation tank (1), and each of the blades (32) is distributed along the circumferential direction of the outer through pipe (31) and is fixedly connected to the outer through pipe (31).

6. The chromium and lead ion separation and recovery device for wastewater according to claim 5, characterized in that: The dispersion mechanism (3) further includes a shunt member (33). The outer through pipe (31) has an outer through inlet (311) and an outer through outlet (312). The outer through inlet (311) is communicated with the inner through outlet (233). The outer through pipe (31) is rotatably connected to the lower end of the inner through pipe (23). The shunt member (33) is communicated with the outer through outlet (312). The blade (32) is of a hollow structure and is provided with a plurality of outer flow holes (321), and each of the blades (32) is respectively communicated with the shunt member (33).

7. The device for separating and recovering chromium and lead ions in wastewater according to claim 5, characterized in that: It further includes a foam scraping mechanism (4). The foam scraping mechanism (4) includes a rotating ring (41) and a plurality of foam scraping components (42). The rotating ring (41) is rotatably connected to the upper end of the outer through pipe (31). Each of the foam scraping components (42) is distributed along the circumferential direction of the rotating ring (41) and is hinged to the rotating ring (41). The foam scraping component (42) is connected with a floating buoy (43), and the foam scraping component (42) can deflect around the hinge point between the horizontal direction and the vertical direction.

8. The device for separating and recovering chromium and lead ions in wastewater according to claim 7, wherein: The foam scraping assembly (42) includes a foam scraping frame (421), a slide member (422), a positioning member (423) and a lifting movable column (424), one end of the positioning member (423) is fixedly connected to the rotating ring (41), the other end of the positioning member (423) is rotatably connected to one end of the lifting movable column (424), the upper end of the slide member (422) is fixedly connected to the rotating ring (41), one end of the foam scraping frame (421) is movably connected to the slide member (422), and the middle part of the foam scraping frame (421) is rotatably connected to the other end of the lifting movable column (424).

9. The device for separating and recovering chromium and lead ions in wastewater according to claim 3, characterized in that: A collecting trough (11) is provided on the top of the side wall of the flotation sedimentation tank (1); the bottom of the collecting trough (11) is arc-shaped; and a collecting pipe (12) is connected to the bottom of the collecting trough (11).

10. The device for separating and recovering chromium and lead ions in wastewater according to claim 7, wherein: A crossbeam (13) is fixedly connected to the top of the flotation sedimentation tank (1), and a driving device (5) is fixedly connected to the crossbeam (13). The driving device (5) is respectively connected to the external pipe (31) and the rotating ring (41) in a transmission manner. The external pipe (31) and the rotating ring (41) rotate in opposite directions.

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