Method for efficiently purifying thallium from hydrometallurgy wastewater

Abstract

The present application relates to a kind of wet metallurgy wastewater high-efficiency purification thallium removal method, belong to sewage treatment technical field.The present application uses multistage grid high-speed ion reactor, and utilizes modified vulcanizing agent to carry out wastewater purification thallium removal under room temperature condition.Thallium-containing smelting wastewater in slurry tank is transported to the bottom of multistage grid high-speed ion reactor by slurry pump under room temperature, simultaneously, modified vulcanizing agent is transported into multistage grid high-speed ion reactor by reagent pump to make it purification thallium removal, the amount of modified vulcanizing agent and the purification time of thallium-containing smelting wastewater in multistage grid high-speed ion reactor are controlled by controlling the flow of slurry pump and reagent pump, waste liquid after purification reaction is separated by liquid-solid, filter residue is discharged regularly, and the filtrate after purification thallium removal enters new liquid storage tank;Slurry tank and the tail gas of new liquid storage tank are discharged to tail gas absorption tower for purification by vacuum unit.The present application realizes high-efficiency purification thallium removal by multistage grid high-speed ion reactor.

Description

TECHNICAL FIELD

[0001] The application relates to a high-efficiency thallium removal method for wet metallurgy wastewater, and belongs to the technical field of wastewater treatment. BACKGROUND

[0002] In a zinc smelting process, thallium in zinc concentrate enters flue gas after roasting at a rate of 70% to 84%, and thallium-containing wastewater is generated after acid washing of the flue gas and enters smelting waste acid wastewater. The thallium-containing wastewater accounts for about 20% to 30% of the total amount of wastewater in a zinc smelting enterprise. At present, the waste water purification treatment in the waste acid treatment system of a domestic wet zinc smelting plant mainly adopts a conventional reaction tank. First, a two-stage lime milk neutralization method is used for pretreatment to neutralize sulfuric acid in the waste acid, and the treated slurry is filtered by a filter press, and the solid is produced in the form of gypsum slag, and the filtrate is neutral wastewater with a pH of 6-8; then, a two-stage deep thallium removal is performed by adding a thallium removal reagent and a complexing agent, and the thallium removal wastewater is separated by the filter press; finally, a lime-iron salt method is used for treatment process to precipitate and remove harmful impurities such as heavy metals and arsenic in the water, and the effluent water quality meets the Discharge Standard of Industrial Pollutants for Lead and Zinc Industry, and is sent to a clean wastewater treatment station for deep treatment. This method has problems such as long reaction time, high energy consumption, and large reagent consumption, especially the thallium removal process needs two-stage purification, and the process is long and the cost is high. Therefore, it is of great significance to develop a high-efficiency purification method for lead and zinc smelting wastewater to realize low-cost and high-efficiency removal of thallium in wet smelting wastewater. SUMMARY

[0003] In view of the problems such as long reaction time, high reagent consumption, and high energy consumption in the traditional wastewater treatment process, the application provides a high-efficiency thallium removal method for wet smelting wastewater, which uses a multi-stage high-speed ion reactor to purify and remove thallium from wastewater at room temperature by using a modified vulcanizing agent. At room temperature, the smelting thallium-containing wastewater in a slurry tank is delivered to the bottom of the multi-stage high-speed ion reactor by a slurry pump, and the modified vulcanizing agent is delivered into the multi-stage high-speed ion reactor by a reagent pump to purify and remove thallium. The amount of the modified vulcanizing agent and the purification time of the smelting thallium-containing wastewater in the multi-stage high-speed ion reactor are controlled by controlling the flow rates of the slurry pump and the reagent pump. The waste liquid after the purification reaction is separated by a vacuum filter, the filter residue is regularly discharged, and the filtered liquid after the thallium removal is stored in a new liquid storage tank. The tail gas of the slurry tank and the new liquid storage tank is discharged to a tail gas absorption tower for purification by a vacuum unit. The application realizes high-efficiency purification and thallium removal by using a high-speed ion reactor, has low energy consumption and low cost, and is clean and environmentally friendly.

[0004] The application discloses a method for efficiently purifying and removing thallium from hydrometallurgy wastewater, and the method is characterized by adopting a multi-stage partitioned high-speed ion reactor and purifying and removing thallium from the hydrometallurgy wastewater containing thallium at room temperature by using a modified vulcanizing agent.

[0005] The specific steps of the method are as follows:

[0006] At room temperature, the hydrometallurgy wastewater containing thallium is added into a slurry tank for stirring and mixing, the hydrometallurgy wastewater containing thallium in the slurry tank is transported to the feed inlet at the bottom center of the multi-stage partitioned reactor at a preset flow rate by a slurry pump, meanwhile, a modified vulcanizing agent solution is transported to the feed inlet at the bottom center of the multi-stage partitioned reactor at a preset flow rate by a reagent pump, the hydrometallurgy wastewater containing thallium and the modified vulcanizing agent solution enter the annular reaction compartment in the innermost layer of the multi-stage partitioned reactor through the feed inlet, the height difference formed by the increasing height of the cylindrical partition from inside to outside is used to realize the flow and mixing of the solution in the multi-stage partitioned reactor from inside to outside, so that the modified vulcanizing agent and thallium ions in the hydrometallurgy wastewater containing thallium are gradually purified and reacted, and the high-speed stirring of the stirring paddle in the multi-stage annular reaction compartment increases the collision probability of the modified vulcanizing agent and the thallium ions in the hydrometallurgy wastewater containing thallium, thereby realizing the purification and removal of the thallium ions.

[0007] The waste liquid after the purification reaction is subjected to liquid-solid separation by a vacuum filter, the filter residue is regularly discharged, and the filtered liquid after the purification and removal of thallium is introduced into a new liquid storage tank; tail gas of the slurry tank and the new liquid storage tank is discharged to a tail gas absorption tower by a vacuum unit for purification.

[0008] A multi-stage high-speed ion reaction system is constructed to realize efficient removal of thallium ions. A concentric multi-stage ring-shaped reaction cell structure is adopted, and a fluid gradient is formed by the height difference of the partition to make the reactants gradually advance and mix, and the mass transfer efficiency is strengthened by high-speed stirring; the reactant ratio is controlled by the coordinated feeding of the slurry pump and the reagent pump to realize rapid reaction at room temperature; the combination of the vacuum filtration system and the tail gas absorption device realizes the continuous separation of the reaction products and the treatment of waste gas; among them, the height gradient design of the concentric ring-shaped reaction cell makes the reactants form a multi-stage mixing reaction path in a limited space, the radial distribution structure of the stirring paddle ensures the mixing intensity in each stage of the reaction cell, and the gradient addition of the modified vulcanizing agent improves the utilization rate of the reagent. The whole system realizes a substantial reduction in reaction time through physical structure innovation, avoiding the complex process of traditional multi-stage reaction tank.

[0009] Preferably, the multi-stage reaction cell 2 is sequentially arranged from inside to outside as the first-stage reaction chamber, the second-stage reaction chamber and the third-stage reaction chamber, the center of the cover 3 is fixedly provided with a shaft sleeve 5, the center of the shaft sleeve 5 is installed and provided with a lower bearing 15, the lower bearing 15 is rotatable in the shaft sleeve 5, the top end of the lower bearing 15 is fixedly connected with the upper bearing 10 through the coupling 13, the lower bearing 15 extends downward into the reactor 2, and the bottom of the lower bearing 15 is sequentially installed and provided with the stirring paddle I 18, the stirring paddle II 17 and the stirring paddle III 16 from inside to outside, and the stirring paddle I 18, the stirring paddle II 17 and the stirring paddle III 16 are sequentially inserted into the first-stage reaction chamber, the second-stage reaction chamber and the third-stage reaction chamber.

[0010] Through the rotating cooperation structure of the shaft sleeve and the lower bearing, a single driving source can control the synchronous rotation of the three-stage stirring paddles, solving the problem of complex structure caused by independent driving devices in the traditional multi-stage reactor; the connection design of the lower bearing and the coupling realizes the stability of power transmission, avoiding the interference of mechanical vibration in the multi-stage stirring process on the reaction system; the hierarchical distribution structure of the stirring paddles forms independent and controllable fluid shear fields in the first-stage, second-stage and third-stage reaction chambers, and by adjusting the insertion depth and position of the stirring paddles, adaptive mixing can be realized according to the viscosity difference of the materials in different reaction stages, and the contact probability of the modified vulcanizing agent and thallium ions is strengthened; the axial superposition layout of the three-stage stirring paddles realizes the precise regulation of multi-region reaction conditions in a limited space, providing a dynamically balanced mixing environment for the step-by-step purification reaction.

[0011] More preferably, the stirring paddle I 18 comprises a sleeve I and stirring blades I fixed on the outer side wall of the sleeve I, the stirring paddle II 17 comprises a sleeve II and stirring blades II fixed on the outer side wall of the sleeve II, the stirring paddle III 16 comprises a sleeve III and stirring blades III fixed on the outer side wall of the sleeve III, the sleeve I, the sleeve II and the sleeve III are overlapped from bottom to top and fixed on the bottom end of the lower bearing 15 by bearing fasteners I 19, and the stirring blades I, the stirring blades II and the stirring blades III are inserted into the first-stage reaction compartment, the second-stage reaction compartment and the third-stage reaction compartment in sequence.

[0012] Through the separate structure design of the sleeve and the stirring blades, the layered and stacked assembly of the stirring paddle assembly in the vertical direction is realized. The sleeve I, the sleeve II and the sleeve III are overlapped from bottom to top and fixed on the bottom end of the lower bearing by the bearing fasteners I, forming an axial compact rigid connection structure, which not only ensures the independent operation stability of each stage of stirring paddles, but also reduces the mechanical vibration risk caused by multi-stage transmission; the stirring blades I, II and III are fixed on the outer side wall of the corresponding sleeve and extend into the corresponding level of the reaction kettle, so that the stirring blades of each stage of reaction compartments can independently optimize the stirring effect according to the fluid characteristics of the level, avoiding the decline of mixing efficiency caused by the single stirring structure that cannot adapt to the multi-stage reaction environment. Through the modular combination of the sleeve and the stirring blades, the multi-stage reinforced mixing dynamics in the multi-stage reaction compartment is realized while the transmission mechanism is simplified.

[0013] More preferably, the top end of the shaft sleeve 5 is fixedly provided with a cover 6, the top of the lower bearing 15 passes through the cover 6 upwards, the center of the kettle cover 3 is provided with a center through hole, a sealing ring 4 is fixedly arranged in the center through hole, a bearing fastener II 14 is arranged in the gap between the sealing ring 4 and the shaft sleeve 5, and the top end of the bearing fastener II 14 is fixedly arranged at the top end of the sealing ring 4. The dynamic rotating seal is formed by the sealing ring 4 and the bearing fastener II 14, which is the core safety protection point of the whole system, preventing the leakage of harmful medium in the reaction kettle.

[0014] More preferably, the multi-stage compartment reaction kettle 2 further comprises a bearing cover 12 and a bracket 7, the center of the bearing cover 12 is fixedly provided with a ball bearing 11, the bottom end of the upper bearing 10 is fixedly connected with the shaft coupling 13 by passing through the inner ring of the ball bearing 11, the bearing cover 12 is fixedly connected with the top end of the bracket 7 through the annular pad plate 8 arranged at the top end of the bearing cover 12 and the fastening bolts, and the bottom end of the bracket 7 is fixedly connected with the kettle cover 3.

[0015] The bearing cap and the support are cooperatively designed to realize the improvement of axial stability and radial sealing of the stirring system; the bearing cap with the ball bearing is arranged to form accurate guidance through the inner ring of the ball bearing when the upper bearing rotates at high speed, thereby reducing the wear caused by the bearing runout; the annular gusset plate and the fastening bolt are used to rigidly connect the bearing cap and the top end of the support, thereby enhancing the load bearing capacity of the bearing cap; the bottom end of the support is fixed with the kettle cover to form a three-dimensional support frame, thereby dispersing the vibration load generated by the stirring system; the three-level fixing structure (bearing cap-support-kettle cover) forms a stable force transmission path, which avoids the resonance phenomenon of the traditional cantilever stirring shaft and eliminates the risk of gap leakage of the sealing ring caused by vibration.

[0016] More preferably, the top end of the upper bearing 10 is fixedly provided with a top cover 9, and the top cover 9 is fixedly connected with the output shaft of the stirring motor.

[0017] The top cover is directly fixed at the top end of the upper bearing and rigidly connected with the output shaft of the stirring motor, thereby realizing the optimization of the power transmission path of the stirring system; as a connecting component, the top cover eliminates the structural redundancy caused by the traditional shaft coupling or transmission chain, so that the power of the stirring motor can be directly transmitted to the stirring paddle in the concentric multi-stage annular reaction cell; the rigid connection mode can reduce the energy loss in the transmission process and avoid the mechanical vibration that may be caused by multi-stage transmission, thereby ensuring the stability of the operation of the stirring paddle under high-speed stirring.

[0018] Preferably, the reaction time of the smelting thallium-containing wastewater and the modified vulcanizing agent solution in the multi-stage divided cell reaction kettle is 6-20s. The annular flow channel structure of the multi-stage divided cell reaction kettle is used to realize the gradual rapid mixing reaction. This time range ensures that the thallium ions and the vulcanizing agent are in sufficient contact to complete the precipitation reaction, and through the shortening of the reaction time of dozens of minutes in the traditional process, the multi-stage purification reaction is completed in a very short time in cooperation with the high-speed stirring device. Precise control of the reaction time avoids excessive reaction caused by the consumption of the vulcanizing agent, and at the same time matches the hydrodynamic characteristics of the multi-stage divided cell reaction kettle, so that the ion exchange and solid-liquid separation continuous treatment of the wastewater is completed in the process of layer-by-layer flow, thereby realizing the synchronous improvement of the reaction efficiency and the equipment operation efficiency.

[0019] Preferably, the stirring speed of the stirring paddle is 600-1200 r / min. The strong turbulent environment generated by high-speed stirring significantly improves the contact frequency and reaction rate of the modified vulcanizing agent with thallium ions in the wastewater. This speed range not only ensures sufficient mixing of the reactants to avoid local concentration unevenness, but also enhances the surface activity of the vulcanizing agent through mechanical shearing, promoting the adsorption and precipitation of thallium ions. At the same time, the upper limit of this speed range avoids the sharp increase in energy consumption and the intensification of equipment wear caused by excessive speed, while the lower limit ensures that the reaction system maintains sufficient kinetic conditions, allowing thallium ions to complete multi-stage purification and removal in a very short reaction time, thereby achieving the goal of efficient and low-cost thallium removal as a whole.

[0020] Preferably, the modified vulcanizing agent is a sodium sulfide / chitosan composite, and the amount of modified vulcanizing agent is 5-10 wt.% of the thallium content in the thallium-containing wastewater. By using the modified vulcanizing agent formed by the combination of sodium sulfide and chitosan, the adsorption of thallium ions by the amino and hydroxyl functional groups on the chitosan molecular chain is combined with the precipitation of thallium ions by sodium sulfide to form a synergistic purification mechanism. Controlling the amount of modified vulcanizing agent within the range of 5-10 wt.% of the thallium content ensures that sodium sulfide reacts fully with thallium ions to form insoluble thallium sulfide precipitate, and reduces the ineffective consumption of sodium sulfide through the adsorption of chitosan, avoiding the risk of secondary pollution caused by excessive sodium sulfide. This composite modified vulcanizing agent can achieve efficient removal of thallium ions while reducing the cost of reagents under a specific ratio, simplifying the steps of traditional multi-stage purification processes.

[0021] More preferably, the content of sodium sulfide in the modified vulcanizing agent is 70-80 wt.%. By limiting the mass fraction of sodium sulfide in the composite modifier, a synergistic system of sodium sulfide and chitosan is established. As the main reactant, a content of sodium sulfide higher than 70% ensures sufficient sulfur ion concentration to form stable sulfide precipitate with thallium ions; and a content not exceeding 80% preserves the reasonable ratio of chitosan, which uses its amino groups on the molecular chain to wrap and fix the thallium sulfide precipitate, preventing the precipitate from redissolving. This ratio range avoids the problem of excess sulfur ions caused by excessive addition of sodium sulfide when using sodium sulfide alone, and overcomes the adsorption capacity limitation of chitosan when used alone, achieving a dual improvement in reagent utilization and precipitate stability through the optimization of the ratio of the two components.

[0022] Preferably, the concentration of the modified vulcanizing agent solution is 0.3-0.5 g / L. By limiting the concentration of the modified vulcanizing agent solution to 0.3-0.5 g / L, the amount of sodium sulfide is accurately controlled while ensuring sufficient reaction of thallium ions. This concentration range ensures that the sodium sulfide / chitosan composite forms a stable dispersion system in the solution, effectively capturing thallium ions in the wastewater, while avoiding the waste of reagents and the subsequent pressure of solid waste treatment caused by excessive sodium sulfide.

[0023] The beneficial effects of the present application are:

[0024] (1) fast reaction speed: the traditional metallurgical wastewater thallium removal process usually needs 2-3h reaction time, the present application combines dynamic flow field design and variable frequency speed regulation, the high-speed stirring device in the reactor makes the solution fully mixed in the multi-stage grid, increases the collision probability of sulfur ions and thallium ions in the solution, the reaction time only needs 6-20S, greatly shortens the reaction time, and is beneficial to the reduction of energy consumption;

[0025] (2) less reagent dosage: the traditional metallurgical wastewater thallium removal process usually needs to add more than 20wt% of the thallium content in the wastewater of the purifying agent, the present application combines the multi-stage grid high-speed ion reaction device, the “multi-stage grid turbulence intensification” and “dynamic flow field synergy” mechanism, which can solve the problems of low mass transfer efficiency and low reagent utilization rate, the reagent dosage only needs 5-10wt% of the thallium content in the wastewater, the reagent consumption is small, and the slag amount is small. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a multi-stage grid high-speed ion reactor structure schematic diagram;

[0027] Figure 2 is a wastewater purification system schematic diagram of the multi-stage grid high-speed ion reactor assembly;

[0028] In the figure, 1 is a feed inlet, 2 is a multi-stage grid reactor, 3 is a cover, 4 is a sealing ring, 5 is a shaft sleeve, 6 is a cover, 7 is a support, 8 is an annular gasket, 9 is a top cover, 10 is an upper bearing, 11 is a ball bearing, 12 is a bearing cover, 13 is a coupling, 14 is a bearing fastener II, 15 is a lower bearing, 16 is a stirring paddle III, 17 is a stirring paddle II, 18 is a stirring paddle I, 19 is a bearing fastener I, and 20 is a discharge port. DETAILED DESCRIPTION

[0029] The present application will be further described in detail below in combination with specific embodiments, but the protection scope of the present application is not limited to the described content.

[0030] As Figure 1As shown, the multi-stage high-speed ion reactor according to the embodiment of the present application comprises a multi-stage reaction kettle 2, a feed inlet 1 is arranged at the center of the bottom of the multi-stage reaction kettle 2, the feed inlet 1 is connected with a slurry tank through a slurry pump, the multi-stage reaction kettle 2 comprises concentric multi-stage annular reaction chambers (three-stage annular reaction chambers, which are annular reaction chamber I, annular reaction chamber II and annular reaction chamber III from inside to outside) separated by cylindrical partitions from inside to outside, the height of the cylindrical partitions increases from inside to outside, the concentric multi-stage annular reaction chambers (three-stage annular reaction chambers) are all provided with stirring paddles (stirring paddle I 18, stirring paddle II 17 and stirring paddle III 16), the top end of the multi-stage reaction kettle 2 is provided with a kettle cover 3, the side surface of the multi-stage reaction kettle 2 is provided with a discharge outlet, the discharge outlet is connected with the liquid inlet of a vacuum filter, the liquid outlet of the vacuum filter is communicated with the inlet of a new liquid storage tank, the gas outlet at the top end of the slurry tank and the new liquid storage tank is communicated with the gas inlet of an exhaust gas absorption tower through a vacuum unit.

[0031] The multi-stage reaction kettle refers to an annular reaction space divided by concentric cylindrical partitions, the height of the partitions increases from inside to outside to form a fluid overflow channel, which can guide the reaction liquid to mix step by step along a predetermined path; the height difference of the cylindrical partitions refers to the height difference between adjacent partitions, which enables the reaction liquid to automatically overflow to the next stage after completing the reaction in the current stage, forming a continuous treatment process. The high-speed stirring of the stirring paddles refers to the independent rotating stirring components arranged in each reaction chamber, which can strengthen the contact between the reactants through mechanical shearing. The modified vulcanizing agent solution refers to a sodium sulfide compound with a modified surface, which has enhanced surface activity and is beneficial to the combination reaction with thallium ions. Through the integrated multi-stage reaction structure, the multi-stage purification process is realized in a single device, eliminating the energy loss caused by material transfer in the traditional process. The annular flow channel design enables the reaction liquid to automatically complete the inter-stage flow without the need for additional conveying equipment. The high-speed stirring system forms strong turbulence in a limited space, shortening the reaction time to seconds, while the traditional tank-type reaction needs tens of minutes.

[0032] The multi-stage reaction kettle 2 comprises a first-stage reaction chamber, a second-stage reaction chamber and a third-stage reaction chamber from inside to outside, the center of the kettle cover 3 is fixedly provided with a shaft sleeve 5, the shaft sleeve 5 is centrally provided with a lower bearing 15, the lower bearing 15 can rotate in the shaft sleeve 5, the top end of the lower bearing 15 is fixedly connected with an upper bearing 10 through a coupling 13, the lower bearing 15 extends downward into the reactor 2, the bottom of the lower bearing 15 is sequentially provided with the stirring paddle I 18, the stirring paddle II 17 and the stirring paddle III 16 from inside to outside, and the stirring paddle I 18, the stirring paddle II 17 and the stirring paddle III 16 are sequentially inserted into the first-stage reaction chamber, the second-stage reaction chamber and the third-stage reaction chamber.

[0033] The shaft sleeve refers to an annular support structure installed in the center of the kettle cover, which is rigidly connected with the kettle cover by welding or bolt fixing method, and is used to bear the rotating movement of the lower bearing. The lower bearing refers to a rotating part with a transmission shaft, which can specifically adopt a double-row angular contact ball bearing. The outer ring is clearance fitted with the inner wall of the shaft sleeve, and the inner ring is connected with the transmission shaft through a key groove to realize the axial positioning of power transmission. The shaft coupling refers to a transmission part connecting the upper and lower bearings, which can specifically adopt an elastic pin coupling. The pin shaft is matched with the flange plate to absorb the vibration deviation in the transmission process. The stirring paddles I, II and III refer to stirring assemblies of different levels, which can specifically adopt three-blade propeller paddle structures. The paddle ends are provided with shear wings with a bending angle of 45°. The paddles are fixed on the outside of the sleeve to form a radial extension structure by bolts.

[0034] When the upper bearing is driven to rotate by external power, the shaft coupling transmits torque to the lower bearing to drive the three-stage stirring paddles to rotate synchronously. The rotating movement of the lower bearing in the shaft sleeve is radially positioned by clearance fitting to avoid shafting deviation caused by centrifugal force. The stirring paddles I, II and III are respectively inserted into the corresponding level of the reaction kettle. When the paddles rotate, axial circulation flow and radial shear flow are respectively formed in the first, second and third reaction chambers. Due to the gradual expansion of the annular space of the three-stage reaction chamber, the linear velocity of the stirring paddle increases with the increase of the radius, forming a stronger turbulent mixing effect in the third reaction chamber. The elastic element of the shaft coupling can compensate the torque fluctuation caused by the viscosity difference of the materials in different levels of the reaction chamber, and keep the synchronous operation of the three-stage stirring system.

[0035] The stirring paddle I 18 includes a sleeve I and a stirring paddle I fixedly arranged on the outer side wall of the sleeve I. The stirring paddle II 17 includes a sleeve II and a stirring paddle II fixedly arranged on the outer side wall of the sleeve II. The stirring paddle III 16 includes a sleeve III and a stirring paddle III fixedly arranged on the outer side wall of the sleeve III. The sleeve I, the sleeve II and the sleeve III are sequentially overlapped from bottom to top and fixedly arranged on the bottom end of the lower bearing 15 by the bearing fastener I 19. The stirring paddle I, the stirring paddle II and the stirring paddle III are sequentially inserted into the first-stage reaction chamber, the second-stage reaction chamber and the third-stage reaction chamber.

[0036] The sleeve refers to a cylindrical support structure for fixing the stirring paddle. The outer side wall of the sleeve fixes the stirring paddle by welding or bolt connection. The inner wall of the sleeve is interference fitted with the bottom end of the lower bearing to realize power transmission. The bearing fastener I refers to a mechanical fixing element for connecting the sleeve and the lower bearing. Specifically, it can adopt a flange plate and high-strength bolt combination structure. The sleeve I, the sleeve II and the sleeve III are axially pressed and fixed by the upper and lower clamping methods to form a rigid connection structure to resist rotational shear force. The stirring paddle refers to a blade structure for realizing fluid mixing. Specifically, it can adopt a folding leaf or turbine blade. The blade installation angle can be adjusted to 15° to 45°. The blade edge can be provided with a serrated structure to enhance the local turbulence intensity.

[0037] The sleeves I, II and III are stacked along the lower bearing axis in sequence and fixed by the bearing fastener I composed of flanges and bolts, forming a rigid transmission chain in axial series. The outer side wall of each sleeve is fixed with the corresponding stirring paddle, and the installation position of the stirring paddle matches the fluid area of the corresponding level reaction cell. When the drive shaft rotates, power is transmitted synchronously to each sleeve through the lower bearing, driving each level stirring paddle to rotate independently in the corresponding reaction kettle. Since the sleeve stacking structure eliminates the gear meshing gap in the traditional multi-shaft transmission, the phase difference of each level stirring paddle during rotation is controlled within 5°, thereby avoiding mechanical vibration caused by asynchronous transmission. The fixed position of the stirring paddle on the outer side wall of the sleeve can be differentially arranged according to the level height of the reaction kettle, for example, the inner layer reaction kettle adopts high-position installed folding paddle to enhance the axial flow, and the outer layer reaction kettle adopts low-position installed turbine paddle to strengthen the radial mixing. Through the combined design of sleeve stacking and bearing fastener, rigid connection and independent spatial layout of multi-level stirring paddles are realized on a single drive shaft, avoiding the structural redundancy of multi-shaft transmission and solving the mixing dead angle problem of single-shaft multi-paddle. The axial compact installation and synchronous stable operation of the stirring assembly in the multi-stage reaction cell are realized, and the energy loss and equipment vibration caused by loose transmission chain are eliminated. The independent spatial layout of each level stirring paddle optimizes the mixing intensity of different reaction stages, the high-position folding paddle of the inner layer reaction kettle accelerates the initial dispersion of the reactants, and the low-position turbine paddle of the outer layer reaction kettle enhances the solid-liquid contact efficiency, thereby improving the overall thallium ion purification reaction rate. The modular design of the sleeve and the bearing fastener enables the level to be individually disassembled and replaced during maintenance of the stirring assembly, reducing the equipment operation and maintenance cost.

[0038] The top end of the shaft sleeve 5 is fixedly provided with a cover 6, the top of the lower bearing 15 passes through the cover 6 upwards, the center of the kettle cover 3 is provided with a center through hole, and a sealing ring 4 is fixedly arranged in the center through hole. The gap between the sealing ring 4 and the shaft sleeve 5 is provided with a bearing fastener II 14, and the top end of the bearing fastener II 14 is fixedly arranged at the top end of the sealing ring 4.

[0039] The multi-stage divided cell reaction kettle 2 further comprises a bearing cover 12 and a support 7. The center of the bearing cover 12 is fixedly provided with a ball bearing 11. The bottom end of the upper bearing 10 is fixedly connected with the shaft coupling 13 by penetrating the inner ring of the ball bearing 11. The bearing cover 12 is fixedly connected with the top end of the support 7 through the annular pad plate 8 arranged at the top end of the bearing cover 12 and the fastening bolts. The bottom end of the support 7 is fixedly connected with the kettle cover 3.

[0040] The bearing cover refers to the rigid shell covering the outside of the ball bearing, used to constrain the radial displacement of the ball bearing. The support refers to the support member connecting the bearing cover and the kettle cover, which can be a welded frame structure of I-beam or channel steel, used to disperse the vibration load transmitted by the stirring system. The ball bearing refers to a precision mechanical element with rolling elements, which can be a deep groove ball bearing or an angular contact bearing, used to reduce the friction resistance when the upper bearing rotates. The annular gasket refers to a circular ring-shaped metal plate with a central through hole, which can be made of stainless steel and processed with bolt holes, used to uniformly distribute the pre-tightening force of the fastening bolts.

[0041] The ball bearing is fixed in the center of the bearing cover, and the upper bearing is rigidly connected with the coupling through the inner ring at the bottom end, so that the rotation axis of the upper bearing is accurately defined. The top end of the bearing cover is connected with the top end of the support by fastening bolts through the annular gasket, forming a detachable rigid interface. The bottom end of the support is welded or bolted to the surface of the kettle cover, forming a continuous support path from the bearing cover to the kettle cover. When the stirring system is running, the inner ring of the ball bearing guides the stable rotation of the upper bearing, avoiding the seal ring wear caused by deflection; the support transmits vibration energy to the kettle cover, reducing the relative displacement between the bearing cover and the seal ring; the combination of the annular gasket and the fastening bolt can adjust the levelness of the bearing cover, ensuring the installation accuracy of the ball bearing. By adding the support and the bearing cover, a three-stage rigid connection structure is formed, which not only improves the stability of the bearing assembly, but also reduces the local stress concentration by dispersing the load.

[0042] The top end of the upper bearing 10 is fixedly provided with a top cover 9, and the top cover 9 is fixedly connected with the output shaft of the stirring motor; the top cover refers to the rigid connecting component covering the top end of the upper bearing, which can be realized by using a flange plate or a metal cover plate, and its function is to form a rigid connection between the output shaft of the stirring motor and the upper bearing, avoiding sliding or deviation during power transmission. The upper bearing refers to a mechanical component that supports the rotational motion of the stirring paddle, which can be realized by using a ball bearing or a sliding bearing, and after the top end is fixedly connected with the top cover, it can directly receive the rotational torque output by the stirring motor, reducing the energy loss of the intermediate transmission link.

[0043] The output shaft of the stirring motor is rigidly connected with the upper bearing through the top cover, and the power transmission path is simplified to a straight-line structure of motor-top cover-upper bearing-stirring paddle. In this process, intermediate transmission components such as couplings and transmission chains are cancelled, and the mechanical clearance and friction resistance of the transmission system are reduced. The rotational kinetic energy output by the stirring motor is directly transmitted to the stirring paddles in the concentric multi-stage annular reaction grid through the top cover, so that each layer of stirring paddles can rotate synchronously at the same speed. Due to the shortening of the power transmission path and the strengthening of the structural rigidity, the stirring paddles will not swing due to transmission system vibration when rotating at high speed, thereby maintaining the stable turbulent flow state of the fluid in the reaction kettle.

[0044] Example 1: A method for efficiently purifying and removing thallium from hydrometallurgy wastewater, which uses a multi-stage partitioned high-speed ion reactor to purify and remove thallium from smelting wastewater containing thallium at room temperature by using a modified sulfidation agent (see Figure 1 and 2 ). The specific steps are as follows:

[0045] At room temperature, smelting wastewater containing thallium (thallium concentration of 3.85 mg / L, pH of 8.75) from a smelter was added to a slurry tank for stirring and mixing. The smelting wastewater containing thallium in the slurry tank was delivered to the feed inlet at the bottom center of the multi-stage partitioned reactor at a preset flow rate (3 m 3 / h) by a slurry pump, and a modified sulfidation agent solution (modified sulfidation agent is a sodium sulfide / chitosan composite, and the sodium sulfide content in the modified sulfidation agent is 70.16 wt.%) with a concentration of 0.3 g / L was delivered to the feed inlet at the bottom center of the multi-stage partitioned reactor at a preset flow rate (4 L / h) by a reagent pump (the amount of modified sulfidation agent is 10 wt.% of the thallium content in the smelting wastewater containing thallium). The smelting wastewater containing thallium and the modified sulfidation agent solution entered the annular reaction compartment in the innermost layer of the multi-stage partitioned reactor through the liquid inlet. The height difference formed by the increasing height of the cylindrical partition from the inside to the outside enabled the solution in the multi-stage partitioned reactor to flow and mix from the inside to the outside, allowing the modified sulfidation agent to react with thallium ions in the smelting wastewater containing thallium in stages. High-speed stirring (600 r / min) by the stirring paddle in the multi-stage annular reaction compartment increased the collision probability of the modified sulfidation agent and thallium ions in the smelting wastewater containing thallium, achieving the purification and removal of thallium ions. The reaction time of the smelting wastewater containing thallium and the modified sulfidation agent solution in the multi-stage partitioned reactor in this example was 20 s.

[0046] The waste liquid after the purification reaction was subjected to liquid-solid separation by a vacuum filter, the filter residue was periodically discharged, and the filtered liquid after the purification and removal of thallium was introduced into a new liquid storage tank. The tail gas from the slurry tank and the new liquid storage tank was discharged to a tail gas absorption tower for conventional purification by a vacuum unit.

[0047] The thallium concentration of the purified liquid in this example was 0.0036 mg / L.

[0048] The difference between this comparative example and Example 1 is that a conventional hydrometallurgical stirring tank is used instead of a multi-stage partitioned high-speed ion reactor, the amount of modified sulfidation agent is 20 wt.% of the thallium content in the smelting wastewater containing thallium, and the reaction time of the smelting wastewater containing thallium and the modified sulfidation agent solution in the conventional hydrometallurgical stirring tank is 3 h.

[0049] The thallium concentration of the purified liquid in the comparative example was 0.0036 mg / L.

[0050] Example 2: The multi-stage partitioned high-speed ion reactor and the wastewater purification system assembled by the multi-stage partitioned high-speed ion reactor in this example are the same as those in Example 1.

[0051] A method for efficiently purifying and removing thallium from hydrometallurgy wastewater, the specific steps are as follows:

[0052] At room temperature, the thallium-containing smelting wastewater (thallium concentration of 6.21 mg / L, pH of 7.32) of a smelter was added to the mixing barrel for stirring and mixing. The thallium-containing smelting wastewater in the mixing barrel was transported to the feed inlet at the bottom center of the multi-stage grid reaction kettle at a preset flow rate (3 m 3 / h) by a mixing pump, and a 0.5 g / L modified vulcanizing agent solution (the modified vulcanizing agent is a sodium sulfide / chitosan composite, and the sodium sulfide content in the modified vulcanizing agent is 79.28 wt.%) was transported to the feed inlet at the bottom center of the multi-stage grid reaction kettle at a preset flow rate (2 L / h) by a reagent pump (the amount of the modified vulcanizing agent is 5 wt.% of the thallium content in the thallium-containing smelting wastewater). The thallium-containing smelting wastewater and the modified vulcanizing agent solution entered the innermost annular reaction grid of the multi-stage grid reaction kettle through the liquid inlet, and the height difference formed by the increasing height of the cylindrical partition from inside to outside realized the sequential flow and mixing of the solution in the multi-stage grid reaction kettle from inside to outside, so that the modified vulcanizing agent and the thallium ions in the thallium-containing smelting wastewater reacted and purified step by step, and the high-speed stirring (1200 r / min) of the stirring paddle in the multi-stage annular reaction grid increased the collision probability of the modified vulcanizing agent and the thallium ions in the thallium-containing smelting wastewater, so as to realize the purification and removal of thallium ions. The reaction time of the thallium-containing smelting wastewater and the modified vulcanizing agent solution in the multi-stage grid reaction kettle in this embodiment was 6 s.

[0053] The waste liquid after the purification reaction was separated by a vacuum filter, the filter residue was discharged regularly, and the filtered liquid after the purification and removal of thallium entered a new liquid storage tank. The tail gas of the mixing barrel and the new liquid storage tank was discharged to a tail gas absorption tower for conventional purification by a vacuum unit.

[0054] The thallium concentration of the purified liquid in this embodiment was 0.0048 mg / L.

[0055] In this embodiment, the multi-stage grid high-speed ion reactor and the wastewater purification system assembled by the multi-stage grid high-speed ion reactor are the same as those in embodiment 1.

[0056] A method for efficiently purifying and removing thallium from hydrometallurgy wastewater, the specific steps are as follows:

[0057] At room temperature, the thallium-containing smelting wastewater (thallium concentration of 6.21 mg / L, pH of 7.32) of a smelter was added to the mixing barrel for stirring and mixing. The thallium-containing smelting wastewater in the mixing barrel was transported to the feed inlet at the bottom center of the multi-stage grid reaction kettle at a preset flow rate (3 m 3h) the feed is delivered to the center of the bottom of the multi-stage compartment reactor, and a 0.4 g / L modified vulcanizing agent solution (the modified vulcanizing agent is a sodium sulfide / chitosan composite, and the sodium sulfide content in the modified vulcanizing agent is 76.86 wt.%) is delivered to the center of the bottom of the multi-stage compartment reactor at a preset flow rate (6 L / h) by using a reagent pump (the amount of the modified vulcanizing agent is 8 wt.% of the thallium content in the smelting thallium-containing wastewater), the smelting thallium-containing wastewater and the modified vulcanizing agent solution enter the annular reaction compartment in the innermost layer of the multi-stage compartment reactor through the liquid inlet, the height difference formed by the increasing height of the cylindrical partition from inside to outside realizes the flow and mixing of the solution in the multi-stage compartment reactor from inside to outside, so that the modified vulcanizing agent and the thallium ions in the smelting thallium-containing wastewater are gradually purified and reacted, and the high-speed stirring (900 r / min) of the stirring paddle in the multi-stage annular reaction compartment increases the collision probability of the modified vulcanizing agent and the thallium ions in the smelting thallium-containing wastewater, so that the thallium ions are purified and removed; the reaction time of the smelting thallium-containing wastewater and the modified vulcanizing agent solution in the multi-stage compartment reactor is 10 s.

[0058] The waste liquid after the purification reaction is subjected to liquid-solid separation by a vacuum filter, the filter residue is regularly discharged, and the filtrate after the purification and removal of thallium enters a new liquid storage tank; the tail gas of the slurry mixing barrel and the new liquid storage tank is discharged to a tail gas absorption tower for conventional purification by a vacuum unit.

[0059] The thallium concentration of the liquid after the purification in this embodiment is 0.0041 mg / L.

[0060] The specific embodiments of the present application are described in detail above, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the purpose of the present application.

Claims

1. A method for efficient purification and thallium removal of wet smelting wastewater, characterized in that, A multi-stage segmented high-speed ion reactor is used to purify thallium-containing wastewater from smelting at room temperature using a modified sulfiding agent. The multi-stage segmented high-speed ion reactor includes a multi-stage segmented reactor (2). The bottom center of the multi-stage segmented reactor (2) is provided with a feed inlet (1). The feed inlet (1) is connected to a slurry tank via a slurry pump. The multi-stage segmented reactor (2) includes concentric multi-stage annular reaction cells divided by cylindrical partitions from the inside to the outside. The height of the cylindrical partitions increases sequentially from the inside to the outside. A stirring paddle is provided in each of the concentric multi-stage annular reaction cells. A lid (3) is provided at the top of the multi-stage segmented reactor (2). A discharge port (20) is provided on the side of the multi-stage segmented reactor (2). The discharge port (20) is connected to the liquid inlet of a vacuum filter. The liquid outlet of the vacuum filter is connected to the inlet of a new liquid storage tank. The gas outlets at the top of the slurry tank and the new liquid storage tank are connected to the gas inlet of the tail gas absorption tower via a vacuum unit. The multi-stage compartmentalized reactor (2) consists of a first-stage reaction chamber, a second-stage reaction chamber, and a third-stage reaction chamber from the inside out. A bushing (5) is fixedly installed at the center of the reactor cover (3). A lower bearing (15) is installed at the center of the bushing (5). The lower bearing (15) can rotate inside the bushing (5). The top of the lower bearing (15) is fixedly connected to the upper bearing (10) through a coupling (13). The lower bearing (15) extends downward into the reactor. A stirring paddle I (18), a stirring paddle II (17), and a stirring paddle III (16) are installed at the bottom of the lower bearing (15) from the inside out. The stirring paddle I (18), the stirring paddle II (17), and the stirring paddle III (16) are inserted into the first-stage reaction chamber, the second-stage reaction chamber, and the third-stage reaction chamber in sequence. The specific steps of the thallium removal purification method are as follows: At room temperature, thallium-containing wastewater from smelting is added to a mixing tank and stirred. The thallium-containing wastewater in the mixing tank is then pumped to the inlet at the center of the bottom of a multi-stage compartmentalized reactor at a preset flow rate using a mixing pump. Simultaneously, a modified sulfurizing agent solution is pumped to the inlet at the center of the bottom of the multi-stage compartmentalized reactor at a preset flow rate using a reagent pump. The thallium-containing wastewater and the modified sulfurizing agent solution enter the innermost annular reaction compartment of the multi-stage compartmentalized reactor through the inlet. The height difference formed by the increasing height of the cylindrical baffles from the inside to the outside allows the solution in the multi-stage compartmentalized reactor to flow and mix sequentially from the inside to the outside, enabling the modified sulfurizing agent to react with the thallium ions in the thallium-containing wastewater in a step-by-step purification process. The high-speed stirring of the agitator in the multi-stage annular reaction compartment increases the collision probability between the modified sulfurizing agent and the thallium ions in the thallium-containing wastewater, thereby achieving the purification and removal of thallium ions. The waste liquid after purification reaction is separated into liquid and solid by a vacuum filter, the filter residue is discharged periodically, and the filtrate after thallium removal enters the new liquid storage tank; the tail gas from the slurry mixing tank and the new liquid storage tank is forced to the tail gas absorption tower for purification by a vacuum unit.

2. The method for efficient purification and thallium removal of hydrometallurgical wastewater according to claim 1, characterized in that: The stirring paddle I (18) includes a sleeve I and a stirring blade I fixedly disposed on the outer wall of the sleeve I. The stirring paddle II (17) includes a sleeve II and a stirring blade II fixedly disposed on the outer wall of the sleeve II. The stirring paddle III (16) includes a sleeve III and a stirring blade III fixedly disposed on the outer wall of the sleeve III. The sleeves I, II, and III are stacked sequentially from bottom to top and fixedly disposed at the bottom end of the lower bearing (15) by bearing fastener I (19). The stirring blades I, II, and III are sequentially inserted into the first-stage reaction chamber, the second-stage reaction chamber, and the third-stage reaction chamber.

3. The method for efficient purification and thallium removal of hydrometallurgical wastewater according to claim 1, characterized in that: A cover (6) is fixedly installed at the top of the bushing (5). The top of the lower bearing (15) passes through the cover (6) upward. A central through hole is opened in the center of the lid (3). A sealing ring (4) is fixedly installed in the central through hole. A bearing fastener II (14) is installed in the gap between the sealing ring (4) and the bushing (5). The top of the bearing fastener II (14) is fixedly installed at the top of the sealing ring (4).

4. The method for efficient purification and thallium removal of hydrometallurgical wastewater according to claim 1, characterized in that: It also includes a bearing cover (12) and a bracket (7). A ball bearing (11) is fixedly installed in the center of the bearing cover (12). The bottom end of the upper bearing (10) passes through the inner ring of the ball bearing (11) and is fixedly connected to the coupling (13). The bearing cover (12) is fixedly connected to the top end of the bracket (7) by an annular pad (8) and fastening bolts installed at the top end of the bearing cover (12). The bottom end of the bracket (7) is fixedly connected to the kettle cover (3). A top cover (9) is fixedly installed at the top end of the upper bearing (10). The top cover (9) is fixedly connected to the output shaft of the stirring motor.

5. The method for efficient purification and thallium removal of hydrometallurgical wastewater according to claim 1, characterized in that: The reaction time between thallium-containing smelting wastewater and modified sulfiding agent solution in a multi-stage compartmentalized reactor is 6~20s.

6. The method for efficient purification and thallium removal of hydrometallurgical wastewater according to claim 1, characterized in that: The stirring speed of the agitator is 600~1200 r / min.

7. The method for efficient purification and thallium removal of hydrometallurgical wastewater according to claim 1, characterized in that: The modified vulcanizing agent is a sodium sulfide / chitosan complex, and the amount of modified vulcanizing agent used is 5-10 wt. of the thallium content in the thallium-containing wastewater from smelting.

8. The method for efficient purification and thallium removal of hydrometallurgical wastewater according to claim 7, characterized in that: The modified vulcanizing agent contains 70-80 wt.% sodium sulfide.

9. The method for efficient purification and thallium removal of hydrometallurgical wastewater according to claim 1, characterized in that: The concentration of the modified vulcanizing agent solution is 0.3~0.5g / L.

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