Method for removing dissolved sulfur from desulfurization and decyanation waste liquid

Abstract

The invention relates to the technical field of dissolved sulfur removal, in particular to a method for removing dissolved sulfur from desulfurization and decyanation waste liquid. Comprising the following steps: S1, firstly pumping pretreated desulfurization and decyanation waste liquid into a reaction tank, then adding a catalyst into the reaction tank, and then adding dilute sulfuric acid with the concentration of 10% into the reaction tank in batches; s2, when the pH value of the solution in the reaction tank is lower than 4, compressed air is introduced into the reaction tank; according to the method, the dilute sulphuric acid is added in three times, so that the dilute sulphuric acid added in three times can be fully diffused after being added each time, the problem of local excessive acid caused by adding a large amount of dilute sulphuric acid in one time is avoided, the pH is prevented from being instantaneously reduced to 2 or below, and the risk that sulfide and cyanide are quickly decomposed into highly toxic gas under strong acid is reduced; the method can reduce by-product treatment difficulty, inhibit concentrated release of reaction heat, prevent damage to stability of the catalyst, maintain system temperature and pressure in a normal reaction range, and promote generation of target products such as elemental sulfur.

Description

Technical Field

[0001] The invention relates to the technical field of dissolved sulfur removal, in particular to a method for removing dissolved sulfur from desulfurization and decyanation wastewater. Background Art

[0002] In industries such as coal chemical industry, coking, natural gas processing, petroleum refining, and non-ferrous metal smelting, sulfur (in the form of sulfides) and cyanide in raw materials (such as coal, natural gas, and ores) are released as toxic gases such as hydrogen sulfide and hydrogen cyanide during high-temperature processing. To meet environmental emission standards, ammonia-based desulfurization processes are often used to purify the gases. This is because ammonia-based desulfurization processes are a highly efficient and energy-efficient wet desulfurization method. As ammonia, as an absorbent, has a stronger alkalinity than calcium-based absorbents, the reaction rate is fast and the absorbent utilization rate is high, resulting in a desulfurization efficiency of up to 95%-99%. The solubility of ammonia in water exceeds 20%, further enhancing the absorption effect. After ammonia absorbs hydrogen sulfide and hydrogen cyanide, the reaction generates desulfurization and decyanation waste liquid containing ammonium sulfite, ammonium sulfate, and ammonium thiosulfate. If the desulfurization and decyanation waste liquid is directly discharged, it will cause environmental pollution. In addition, the salt substances such as ammonium sulfite, ammonium sulfate, ammonium thiosulfate in the desulfurization and decyanation waste liquid can be recycled as industrial raw materials such as sulfur and thiocyanate. Therefore, directly discharging the desulfurization and decyanation waste liquid will also cause a waste of resources. The method of removing dissolved sulfur from desulfurization and decyanation wastewater is a typical wet oxidation treatment process. Its core principle is to convert sulfides in the wastewater (such as sulfite, bisulfite, and thiosulfate in desulfurization and decyanation wastewater) into separable elemental sulfur or volatile sulfur dioxide gas through chemical reactions. However, the traditional method of adding dilute acid is prone to cause the local acid concentration in the reactor to be too high due to uneven mixing, which makes the sodium sulfide, sodium hydrosulfide and other sulfides and cyanide in the desulfurization and decyanation wastewater react rapidly with hydrogen ions in the local strong acid environment (pH will be instantaneously lower than 2), which not only causes the system temperature to rise sharply (locally up to 100 ° C or above) and the pressure to surge (beyond the micro-positive pressure control range), but also accelerates the generation of highly toxic by-product gas (sulfide is quickly converted into hydrogen sulfide under strong acid, and cyanide is decomposed into HCN), increasing the difficulty of subsequent by-product treatment. At the same time, excessive acid will also destroy Fe 3+ Stability of the catalyst (e.g. formation of [FeCl4] - complex), reducing its catalytic efficiency for the oxidation of sulfides, thereby leading to a decrease in the yield of target products such as elemental sulfur.

[0003] In view of this, in order to overcome the above technical problems, the present invention proposes a method for removing dissolved sulfur from desulfurization and decyanation wastewater, which solves the above technical problems. Summary of the Invention

[0004] In order to make up for the shortcomings of the existing technology, the present invention proposes a method for removing dissolved sulfur from desulfurization and decyanation waste liquid. The present invention adopts a method of adding dilute sulfuric acid three times, so that the dilute sulfuric acid added three times can be fully diffused after each addition, thereby avoiding the local over-acid problem caused by adding a large amount of dilute sulfuric acid at one time. It not only avoids the pH from dropping below 2 instantaneously and reduces the risk of sulfide and cyanide quickly decomposing into highly toxic gases under strong acid, thereby reducing the difficulty of by-product treatment, but also can inhibit the concentrated release of reaction heat, prevent the destruction of catalyst stability, maintain the system temperature and pressure within the normal reaction range, and promote the formation of target products such as elemental sulfur.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a method for removing dissolved sulfur from desulfurization and decyanation wastewater according to the present invention comprises the following steps: S1: First, pre-treat the desulfurization and decyanation waste liquid to remove suspended particles, floating oil and other insoluble matter, then pump the pre-treated desulfurization and decyanation waste liquid into the reaction tank, and add ferric chloride as a catalyst into the reaction tank. Control the reaction temperature at 60-90°C and the reaction pressure at 0.1-0.3 MPa. Then, add 10% dilute sulfuric acid into the reaction tank in batches to maintain the pH value of the solution in the reaction tank in the range of 2-4. S2: When the pH value of the solution in the reaction tank is lower than 4, compressed air is introduced into the reaction tank. The compressed air temperature is 60-80°C and the reaction time is 2-5 hours. S3: The gaseous products generated during the reaction are directly transported to the absorption tower through the exhaust port above the reaction tank. The waste liquid at the bottom of the reaction tank is pumped into the centrifuge after the reaction is completed. The centrifuge filters the sulfur particles in the waste liquid, and the centrifuged waste liquid is transported to the transfer tank. S4: Before the centrifuged waste liquid is transported to the transfer tank, activated carbon is filled into the transfer tank so that the organic sulfur compounds in the waste liquid poured into the transfer tank are adsorbed by the activated carbon, and finally a liquid without dissolved sulfur is obtained.

[0006] Preferably, in S1, the dilute sulfuric acid with a concentration of 10% is added three times, the temperature of the dilute sulfuric acid added for the first time is 55-60°C, the temperature of the dilute sulfuric acid added for the second time is 65-75°C, and the temperature of the dilute sulfuric acid added for the third time is 75-85°C.

[0007] Preferably, in S2, during the first addition of dilute sulfuric acid, compressed air at 55-60°C is first introduced. After reacting for 10-20 minutes, the temperature of the introduced compressed air is controlled to rise slowly to 65-75°C. After the second addition of dilute sulfuric acid, the temperature of the introduced compressed air is controlled to rise slowly to 75-85°C.

[0008] Preferably, the reaction tank comprises a tank body; the tank body is provided with an exhaust port, an infusion port, a liquid inlet, a liquid outlet and an air inlet in sequence from top to bottom; a gas distributor connected to the air inlet is installed at the bottom of the tank body; a mounting plate is fixedly installed inside the tank body; the lower end of the mounting plate is rotatably connected to a rotating rod; the surface of the rotating rod is slidably connected to a rotating ring; the surface of the rotating ring is fixedly connected to a vane plate; a cavity is provided inside the mounting plate; a bevel gear ring and a bevel gear shaft that mesh with each other are provided in the cavity; the bevel gear ring is fixedly connected to the upper end of the rotating rod; a driving motor is installed on one side of the tank body; the bevel gear shaft is fixedly connected to the output shaft of the driving motor; the surface of the vane plate is provided with a liquid outlet; the surface of the rotating rod is provided with an annular groove connected to the infusion port; the annular groove and the liquid outlet port are connected by a spring hose; a blocking unit is installed in the mounting plate; the blocking unit is used to block the infusion port; A traction unit is installed inside the tank body; the traction unit is used to pull the swivel to slide up and down along the rotating rod.

[0009] Preferably, the blocking unit includes a blocking plate; a groove connected to the infusion port is provided inside the mounting plate; the blocking plate is slidingly and sealingly connected in the groove; the blocking plate and the bottom of the groove are connected via a supporting spring; a through hole is provided on the surface of the blocking plate; an L-shaped hole is provided at one end of the blocking plate; an air duct connected to the air inlet is provided at one end of the groove close to the L-shaped hole; and an electromagnetic valve is installed in the air duct.

[0010] Preferably, the traction unit includes a traction rod; a fiberglass rope is fixedly connected to the upper end of the swivel; the end of the fiberglass rope away from the swivel passes through the center of the swivel and is connected to the surface of the traction rod; the output shaft of the drive motor is connected to the traction rod through a transmission unit.

[0011] Preferably, the transmission unit includes a worm wheel and a worm; a bevel gear ring is installed at the end of the bevel gear shaft away from the rotating rod; the worm wheel is fixedly connected to the traction rod; the worm is rotatably connected to the outer wall of the tank; a bevel gear shaft is provided on the side of the worm wheel away from the worm; there are two bevel gear shafts; a slide groove is provided on the outer wall of the tank; a U-shaped frame is slidably connected in the slide groove; the U-shaped frame is connected to the upper end wall of the slide groove by a connecting spring; the two bevel gear shafts are rotatably connected to the two ends of the U-shaped frame; the rotating rod is located between the two bevel gear shafts; the two bevel gear shafts are both connected to the worm belt drive through a transmission belt; the upper end wall of the slide groove is inlaid with an electromagnetic sheet.

[0012] Preferably, the inner wall of the transmission belt is provided with tooth grooves; the bevel gear shaft and the surface of the worm are both fixedly connected with spur gear rings; the spur gear rings are slidably connected to the tooth grooves on the inner wall of the transmission belt.

[0013] Preferably, a bellows is sleeved on the surface of the rotating rod; one end of the bellows is fixedly connected to the rotating rod, and the other end is fixedly connected to the swivel; the spring hose and the bellows are both made of PTFE material.

[0014] The beneficial effects of the present invention are as follows: The present invention provides a method for adding dilute sulfuric acid three times, so that the dilute sulfuric acid added three times can be fully diffused after each addition, thereby avoiding the problem of local over-acidity caused by adding a large amount of dilute sulfuric acid at one time. Not only does it prevent the pH from instantly dropping below 2 and reduce the risk of sulfide and cyanide quickly decomposing into highly toxic gases under strong acid, thereby reducing the difficulty of by-product treatment, but it can also suppress the concentrated release of reaction heat, prevent the damage to the stability of the catalyst, maintain the system temperature and pressure within the normal reaction range, and promote the generation of target products such as elemental sulfur.

[0015] The present invention is provided with a traction rod. When it is necessary to control the blade plate to rise, the driving motor can drive the bevel gear ring to rotate through the bevel gear shaft, so that the rotating bevel gear drives the bevel gear shaft meshed with the bevel gear to rotate, so that the bevel gear shaft drives the worm and the worm wheel to rotate through the transmission belt, so that the worm wheel drives the traction rod to rotate, so that the rotating traction rod can pull the glass fiber rope connected to it to be wrapped around its surface, so that the glass fiber rope pulls the rotating ring to drive the blade plate to rise, so that the rising blade plate can fully stir and mix the desulfurization and decyanation waste liquid and the ferric chloride aqueous solution in the upper part of the reaction tank under the drive of the rotating rod, thereby ensuring the uniformity of distribution of the ferric chloride aqueous solution in the reaction tank, improving the catalytic oxidation effect of the ferric chloride aqueous solution on the overall desulfurization and decyanation waste liquid, and further accelerating the rate of removing dissolved sulfur from the desulfurization and decyanation waste liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] Figure 1 is a flow chart of the method of the present invention; Figure 2 It is a perspective view of the reaction tank used in the present invention; Figure 3 It is a partial cross-sectional view of the reaction tank used in the present invention; Figure 4 yes Figure 3 Enlarged view of point A in the middle; Figure 5 It is a structural schematic diagram of the reaction tank used in the present invention; Figure 6 yes Figure 5 Enlarged view of point B in the middle; Figure 7 It is a structural schematic diagram of the mounting plate used in the present invention; Figure 8 yes Figure 7Enlarged view of point C in the middle; In the figure: 1, tank body; 11, exhaust port; 12, infusion port; 13, liquid inlet; 14, liquid outlet; 15, air inlet; 16, gas distributor; 17, drive motor; 2, mounting plate; 21, rotating rod; 211, annular groove; 212, spring hose; 22, rotating ring; 221, blade; 222, liquid outlet; 23, cavity; 231, bevel gear ring; 232, bevel gear shaft; 233, bevel gear ring; 24, concave Groove; 241, baffle; 242, support spring; 243, through hole; 244, L-shaped hole; 245, airway; 246, solenoid valve; 25, traction rod; 251, fiberglass rope; 26, worm gear; 261, worm; 27, bevel gear shaft; 271, slide; 272, U-shaped frame; 273, connecting spring; 274, electromagnetic sheet; 275, transmission belt; 276, tooth groove; 28, spur gear ring; 29, bellows. DETAILED DESCRIPTION

[0018] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0019] like Figures 1 to 8 As shown, the method for removing dissolved sulfur from desulfurization and decyanation wastewater of the present invention comprises the following steps: S1: First, pre-treat the desulfurization and decyanation waste liquid to remove suspended particles, floating oil and other insoluble substances, then pump the pre-treated desulfurization and decyanation waste liquid into the reaction tank, and add ferric chloride as a catalyst into the reaction tank. Control the reaction temperature at 60-90 ° C and the reaction pressure at 0.1-0.3 MPa. Then, add 10% dilute sulfuric acid into the reaction tank in batches to maintain the pH value of the solution in the reaction tank in the range of 2-4. S2: When the pH value of the solution in the reaction tank is lower than 4, compressed air is introduced into the reaction tank. The compressed air temperature is 60-80°C and the reaction time is 2-5 hours. S3: The gaseous products generated during the reaction are directly transported to the absorption tower through the exhaust port 11 above the reaction tank. The waste liquid at the bottom of the reaction tank is pumped into a centrifuge after the reaction is completed. The centrifuge filters the sulfur particles in the waste liquid, and the centrifuged waste liquid is transported to the transfer tank. S4: Before the centrifuged waste liquid is transported to the transfer tank, activated carbon is filled into the transfer tank so that the organic sulfur compounds in the waste liquid poured into the transfer tank are adsorbed by the activated carbon, and finally a liquid without dissolved sulfur is obtained.

[0020] As an embodiment of the present invention, in S1, the dilute sulfuric acid with a concentration of 10% is added three times, the temperature of the dilute sulfuric acid added for the first time is 55-60°C, the temperature of the dilute sulfuric acid added for the second time is 65-75°C, and the temperature of the dilute sulfuric acid added for the third time is 75-85°C.

[0021] As an embodiment of the present invention, in S2, during the first addition of dilute sulfuric acid, compressed air at 55-60°C is first introduced. After reacting for 10-20 minutes, the temperature of the introduced compressed air is controlled to slowly rise to 65-75°C. After the second addition of dilute sulfuric acid, the temperature of the introduced compressed air is controlled to slowly rise to 75-85°C.

[0022] During operation, the traditional method of adding dilute acid is prone to cause excessive acid concentration in the local reaction tank due to uneven mixing, resulting in a local strong acid environment (pH will be instantaneously lower than 2), and the sodium sulfide, sodium hydrosulfide and other sulfides and cyanide in the desulfurization and decyanation waste liquid will react rapidly with hydrogen ions, which will not only cause the system temperature to rise sharply (locally up to 100 ° C or above) and the pressure to surge (beyond the micro-positive pressure control range), but also accelerate the generation of highly toxic by-product gas (sulfide is quickly converted into hydrogen sulfide under strong acid, and cyanide is decomposed into HCN), increasing the difficulty of subsequent by-product treatment. At the same time, excessive acid will also destroy Fe 3+ Stability of the catalyst (e.g. formation of [FeCl4] - complex), reducing its catalytic efficiency for the oxidation of sulfides, thereby leading to a decrease in the yield of target products such as elemental sulfur.

[0023] To this end, the present invention provides a method for adding dilute sulfuric acid three times, so that the dilute sulfuric acid added three times can be fully diffused after each addition, thereby avoiding the problem of local over-acidity caused by adding a large amount of dilute sulfuric acid at one time. This not only prevents the pH from instantly dropping below 2 and reduces the risk of sulfide and cyanide rapidly decomposing into highly toxic gases under strong acid, thereby reducing the difficulty of by-product treatment, but also can suppress the concentrated release of reaction heat, prevent the destruction of catalyst stability, maintain the system temperature and pressure within the normal reaction range, and promote the production of target products such as elemental sulfur.

[0024] Before the desulfurization and decyanation waste liquid is pumped into the reaction tank, the user first transports the desulfurization and decyanation waste liquid to a static sedimentation tank and a filter for pretreatment to filter out impurities such as suspended particles, floating oil and other insoluble matter. The pretreated desulfurization and decyanation waste liquid is transported to a heater and heated to 60°C before being transported to the reaction tank. Since ferric chloride is highly soluble in water, during the pretreatment of the desulfurization and decyanation waste liquid, ferric chloride is made into an aqueous solution and stored in a dissolving tank. The dissolving tank is connected to the reaction tank through a connecting pipe. When the pretreated desulfurization and decyanation waste liquid is pumped into the reaction tank, the ferric chloride aqueous solution in the dissolving tank is controlled to be pumped into the reaction tank. At the same time, the stirring equipment in the reaction tank stirs the solution pumped into the reaction tank to fully mix the ferric chloride aqueous solution with the pretreated desulfurization and decyanation waste liquid.

[0025] After the desulfurization and decyanation waste liquid is completely transported to the reaction tank, dilute sulfuric acid at 55-60°C is added to the reaction tank for the first time. The temperature of the first addition of dilute sulfuric acid is set to 55-60°C because the initial reaction system temperature is relatively low and needs to be gradually increased to control the reaction. When the dilute sulfuric acid is added for the first time, the concentration of the desulfurization and decyanation waste liquid as a reactant is the highest and the reaction is the most intense. If the initial temperature of the added dilute sulfuric acid is too high, it is easy to aggravate the problem of local overheating in the reaction tank. In addition, the method for removing dissolved sulfur from the desulfurization and decyanation waste liquid adopts an oxidation-reduction reaction, that is, the overall reaction system is an exothermic reaction. During the addition of dilute sulfuric acid, heat will be generated due to the reaction. Therefore, by setting the temperature of the first addition of dilute sulfuric acid to 55-60°C, the added dilute sulfuric acid with a lower temperature can absorb the reaction heat and avoid local overheating. Therefore, by setting the temperature of the first addition of dilute sulfuric acid to 55-60°C, the violent exothermic reaction in the initial stage can be suppressed, local overheating can be avoided, and heat accumulation leading to side reactions and safety problems can be prevented.

[0026] During the first addition of dilute sulfuric acid into the reaction tank, the external air storage tank is controlled to deliver dry, clean compressed air to the air heater for heating, so that the air heater heats the compressed air to 55-60°C. The compressed air at 55-60°C is delivered to the reaction tank. By introducing dry, clean compressed air into the reaction tank, the internal pressure of the reaction tank is always slightly higher than the external atmospheric pressure, thereby maintaining a slightly positive pressure state inside the reaction tank. The dry, clean compressed air delivered to the reaction tank passes through the distributor, and the distributor disperses the compressed air to form tiny bubbles, so that the tiny bubbles rise in the reaction solution. During the rising process of the bubbles, the oxygen in the bubbles, as a reactant of the oxidation reaction, promotes the reaction through gas-liquid contact. In addition, the rising bubbles will also carry the gas products (such as sulfur dioxide and ammonia) generated by the reaction to achieve product separation. The reason for setting The temperature of the compressed air initially introduced is 55-60°C. The purpose is to enable the compressed air initially introduced to absorb the reaction heat and avoid local overheating. After 10-20 minutes of reaction, the first addition of dilute sulfuric acid has been completed, and the dilute sulfuric acid at this time is also evenly dispersed under the stirring of the stirring device in the reaction tank. Therefore, the user needs to control the air heater to increase the heating temperature of the compressed air, so that the temperature of the compressed air slowly rises to 80-90°C, thereby increasing the reaction rate while the reaction proceeds stably, and improving the efficiency of removing dissolved sulfur from the desulfurization and decyanation waste liquid. In addition, after the first addition of dilute sulfuric acid, the sulfur dioxide gas generated by the reaction will be discharged from the exhaust port 11 at the upper end of the reaction tank. The discharged sulfur dioxide gas will take away heat, so increasing the temperature of the compressed air is also to compensate for the temperature loss in the reaction tank to maintain the temperature range required for the reaction in the reaction tank.

[0027] When adding dilute sulfuric acid for the second time, the sulfide concentration in the desulfurization and decyanation waste liquid decreases, the reaction heat release rate slows down, and at the same time, because the waste liquid is diluted, the specific heat capacity increases, and the temperature rises slowly. In addition, the reaction gas such as sulfur dioxide takes away the heat, further reducing the temperature of the reaction system. Therefore, it is necessary to increase the temperature of the second addition of dilute sulfuric acid. The temperature of the second addition of dilute sulfuric acid is set to 70-80℃ to compensate for these heat losses and ensure that the reaction temperature is maintained within the normal reaction temperature range of 60-90℃. The temperature of the compressed air introduced is controlled to be maintained within the range of 70-80℃. This is because after the addition of dilute sulfuric acid, the system has been heated due to acid-base neutralization and oxidation reaction. At a higher temperature, if compressed air with a temperature lower than that of dilute sulfuric acid is introduced, a "low-temperature zone" will be formed locally, causing the reaction rate in this area to drop sharply, slowing the diffusion rate of dilute sulfuric acid in this area, and prolonging the reaction time with sulfides in the waste liquid, which reduces the reaction rate. The reduced reaction rate will cause excessive dissolution of oxygen, causing deep oxidation of the excess oxygen and unreacted sulfides, resulting in the formation of by-product salts. Therefore, ensuring that the temperature of the incoming compressed air is maintained in the range of 70-80°C can effectively reduce the problem of excessive dissolution of oxygen in the compressed air, not only reducing the waste of compressed air, but also reducing the formation of by-product salts, thereby ensuring the forward progress of the reaction.

[0028] When dilute sulfuric acid is added for the third time, the concentration of the reactants is further reduced, the dilution effect is more significant, and the escape of sulfur dioxide gas will continue to take away heat. At this time, the temperature of the dilute sulfuric acid needs to be further increased to compensate for the heat loss. Therefore, the temperature of the third addition of dilute sulfuric acid is set to 75-85°C. In order to prevent the temperature of the incoming compressed air from being lower than the temperature of the dilute sulfuric acid, after the second addition of dilute sulfuric acid, the temperature of the incoming compressed air is controlled to rise slowly to 75-85°C, thereby ensuring that the reaction can always proceed in a positive and stable manner. In addition, the reason why the temperature of the compressed air is set to rise slowly to 75-85°C is because at this time the reaction of removing dissolved sulfur from the desulfurization and decyanation waste liquid in the reactor has reached the middle and late stages, the concentration of the reactants is further reduced, and the dilution effect is more significant. At this time, the moisture content in the reactor is large. Increasing the temperature of the dry and clean compressed air introduced can increase the evaporation of moisture, thereby reducing the rate of decrease in the reactant concentration and increasing the rate of removal of dissolved sulfur from the desulfurization and decyanation waste liquid.

[0029] After the reaction is completed, the residual waste liquid in the reaction tank is pumped into the centrifuge through the liquid outlet 14, so that the centrifuge filters the elemental sulfur particles in the waste liquid. The waste liquid after centrifugation is transported to the transfer tank, so that the activated carbon filled in the transfer tank adsorbs the organic sulfur compounds in the waste liquid, and finally a liquid without dissolved sulfur is obtained.

[0030] As an embodiment of the present invention, the reaction tank includes a tank body 1; the tank body 1 is provided with an exhaust port 11, an infusion port 12, a liquid inlet 13, a liquid outlet 14 and an air inlet 15 in sequence from top to bottom; a gas distributor 16 connected to the air inlet 15 is installed at the bottom of the tank body 1; a mounting plate 2 is fixedly installed inside the tank body 1; a rotating rod 21 is rotatably connected to the lower end of the mounting plate 2; a rotating ring 22 is slidably connected to the surface of the rotating rod 21; a blade 221 is fixedly connected to the surface of the rotating ring 22; a cavity 23 is provided inside the mounting plate 2; a cavity 23 is provided inside the cavity There are a bevel gear ring 231 and a bevel gear shaft 232 that mesh with each other; the bevel gear ring 231 is fixedly connected to the upper end of the rotating rod 21; a drive motor 17 is installed on one side of the tank body 1; the bevel gear shaft 232 is fixedly connected to the output shaft of the drive motor 17; a liquid outlet 222 is formed on the surface of the vane 221; an annular groove 211 is formed on the surface of the rotating rod 21, which is connected to the infusion port 12; the annular groove 211 and the liquid outlet 222 are connected by a spring hose 212; a blocking unit is installed in the mounting plate 2; the blocking unit is used to block the infusion port 12; A traction unit is installed inside the tank body 1 ; the traction unit is used to pull the swivel 22 to slide up and down along the rotating rod 21 .

[0031] As an embodiment of the present invention, the blocking unit includes a blocking plate 241; a groove 24 connected to the infusion port 12 is opened inside the mounting plate 2; the blocking plate 241 is slidingly and sealingly connected in the groove 24; the blocking plate 241 and the bottom of the groove 24 are connected by a support spring 242; a through hole 243 is opened on the surface of the blocking plate 241; an L-shaped hole 244 is opened at one end of the blocking plate 241; an air duct 245 connected to the air inlet 15 is opened at one end of the groove 24 close to the L-shaped hole 244; and an electromagnetic valve 246 is installed in the air duct 245.

[0032] As an embodiment of the present invention, the traction unit includes a traction rod 25; a glass fiber rope 251 is fixedly connected to the upper end of the swivel 22; the end of the glass fiber rope 251 away from the swivel 22 passes through the center of the swivel rod 21 and is connected to the surface of the traction rod 25; the output shaft of the drive motor 17 and the traction rod 25 are connected through a transmission unit.

[0033] As an embodiment of the present invention, the transmission unit includes a worm wheel 26 and a worm 261; the bevel gear shaft 232 is installed with a bevel gear ring 233 at one end away from the rotating rod 21; the worm wheel 26 is fixedly connected to the traction rod 25; the worm 261 is rotatably connected to the outer wall of the tank body 1; the side of the worm wheel 26 away from the worm 261 is provided with a bevel gear shaft 27; there are two bevel gear shafts 27; the outer wall of the tank body 1 is provided with a slide groove 271; a U-shaped frame 272 is slidably connected in the slide groove 271; the U-shaped frame 272 and the upper end wall of the slide groove 271 are connected by a connecting spring 273; the two bevel gear shafts 27 are rotatably connected to the two ends of the U-shaped frame 272; the rotating rod 21 is located between the two bevel gear shafts 27; the two bevel gear shafts 27 are both connected to the worm 261 through a transmission belt 275; the upper end wall of the slide groove 271 is inlaid with an electromagnetic sheet 274.

[0034] As an embodiment of the present invention, a tooth groove 276 is opened on the inner wall of the transmission belt 275; a spur gear ring 28 is fixedly connected to the surface of the bevel gear shaft 27 and the worm 261; the spur gear ring 28 is slidably connected to the tooth groove 276 on the inner wall of the transmission belt 275.

[0035] As an embodiment of the present invention, a bellows 29 is provided on the surface of the rotating rod 21; one end of the bellows 29 is fixedly connected to the rotating rod 21, and the other end is fixedly connected to the rotating ring 22; the spring hose 212 and the bellows 29 are both made of PTFE material; During operation, the gas distributor 16 is connected to the external air heater through the air inlet 15, and the liquid inlet 13 is connected to the heater of the desulfurization and decyanation waste liquid and the dissolution tank of ferric chloride. After the user heats the pretreated desulfurization and decyanation waste liquid, it is transported to the reaction tank through the liquid inlet 13. At the same time, the dissolution tank transports the ferric chloride aqueous solution to the liquid inlet 13 to mix with the heated desulfurization and decyanation waste liquid and enter the reaction tank. At this time, the drive motor 17 is controlled to operate so that the drive motor 17 can drive the bevel gear ring 231 to rotate through the bevel gear shaft 232, so that the bevel gear ring 231 drives the fixed rotating rod 21 to rotate, so that the rotating rod 21 can drive the swivel 22 connected to the sliding connection to rotate, so that the swivel 22 drives the blade 221 to rotate, so that the blade 221 stirs the desulfurization and decyanation waste liquid and the ferric chloride aqueous solution in the reactor during the rotation, so that the desulfurization and decyanation waste liquid and the ferric chloride aqueous solution are evenly mixed.

[0036] As the desulfurization and decyanation waste liquid and the ferric chloride aqueous solution are continuously added, the liquid levels of the desulfurization and decyanation waste liquid and the ferric chloride aqueous solution continue to rise. In order to enable the blade 221 to fully stir and mix the desulfurization and decyanation waste liquid and the ferric chloride aqueous solution in the upper part of the reaction tank, the present invention is provided with a traction rod 25. When it is necessary to control the blade 221 to rise, the drive motor 17 can drive the bevel gear ring 233 to rotate through the bevel gear shaft 232, so that the rotating bevel gear ring 233 drives the bevel gear shaft 27 meshed with it to rotate, so that the bevel gear shaft 27 drives the worm 261 with the worm wheel 2 through the transmission belt 275. 6 rotates, so that the worm gear 26 drives the traction rod 25 to rotate, so that the rotating traction rod 25 can pull the glass fiber rope 251 connected thereto to be wrapped around its surface, so that the glass fiber rope 251 pulls the rotating ring 22 to drive the blade 221 to rise, so that the rising blade 221 can fully stir and mix the desulfurization and decyanation waste liquid and the ferric chloride aqueous solution in the upper part of the reaction tank under the drive of the rotating rod 21, thereby ensuring the uniformity of the distribution of the ferric chloride aqueous solution in the reaction tank, improving the catalytic oxidation effect of the ferric chloride aqueous solution on the desulfurization and decyanation waste liquid as a whole, and thereby accelerating the rate of removing dissolved sulfur from the desulfurization and decyanation waste liquid.

[0037] By fixing a spur gear ring 28 on the surface of the bevel gear shaft 27 and the worm 261, and providing a tooth groove 276 on the inner wall of the transmission belt 275, the bevel gear shaft 27 and the worm 261 are mechanically driven through the transmission belt 275. When the electromagnetic sheet 274 adsorbs the U-shaped frame 272 and slides in the slide groove 271, the U-shaped frame 272 drives the upper and lower bevel gear shafts 27 to move up and down. The transmission belt 275 is made of PTFE material, so that the friction between the transmission belt 275 and the bevel gear shaft 27 and the worm 261 is small. The reduction enables the two bevel gear shafts 27 to drive the transmission belt 275 to move synchronously, so that the transmission belt 275 can slide up and down along the spur gear on the surface of the worm 261. In order to ensure stable transmission between the bevel gear shaft 27 and the worm 261, a tooth groove 276 is provided on the inner wall of the transmission belt 275, which satisfies the requirement that the transmission belt 275 can slide up and down along the spur gear on the surface of the worm 261, and can also ensure stable transmission between the bevel gear shaft 27 and the worm 261, thereby ensuring the normal and stable operation of the present invention.

[0038] When the blade 221 rises to the liquid level of the desulfurization and decyanation waste liquid, the electromagnetic sheet 274 is energized, so that the electromagnetic sheet 274 can absorb the U-shaped frame 272 and squeeze the connecting spring 273 to rise, so that the U-shaped frame 272 drives the two bevel gear shafts 27 to rise synchronously, so that the upper bevel gear shaft 27 is separated from the bevel gear ring 233, and the lower bevel gear shaft 27 is engaged with the bevel gear ring 233, and the driving motor 17 is controlled to run so that the driving motor 17 can drive the lower bevel gear shaft 27 to rotate, so that the lower bevel gear shaft 27 is driven by the transmission belt 275. The movable worm 261 rotates in the opposite direction, so that the worm 261 drives the worm wheel 26 to rotate in the opposite direction, so that the worm wheel 26 drives the traction rod 25 to rotate in the opposite direction, so that the glass fiber rope 251 wrapped around the surface of the traction rod 25 is released. At this time, the blade 221 slowly slides downward along the rotating rod 21 under the action of its own gravity. Since the driving motor 17 has been driving the rotating rod 21 to rotate through the bevel gear shaft 232, the slowly descending blade 221 is driven by the rotating rod 21 to stir the solution in the reaction tank again, thereby further improving the mixing effect of the desulfurization and decyanation waste liquid and the ferric chloride aqueous solution in the reaction tank.

[0039] After the addition of the desulfurization and decyanation waste liquid is completed, the first addition of dilute sulfuric acid is started. At this time, the external dilute sulfuric acid storage tank is controlled to pump 10% concentration dilute sulfuric acid into the reaction tank through the infusion port 12, so that the dilute sulfuric acid entering the infusion port 12 can enter the groove 24 through the infusion port 12. Since the groove 24 is slidingly sealed with a baffle plate 241, the dilute sulfuric acid flowing to the groove 24 is blocked by the baffle plate 241; a through hole 243 is provided on the surface of the baffle plate 241, and in the initial state, the through hole 243 on the surface of the baffle plate 241 is connected to the infusion port 12, so that the dilute sulfuric acid flowing to the groove 24 flows into the annular groove 211 through the through hole 243, and the dilute sulfuric acid entering the annular groove 211 flows into the liquid outlet 222 on the surface of the blade 221 through the spring hose 212, so that the dilute sulfuric acid flowing into the liquid outlet 222 can flow out from the port of the liquid outlet 222. Since the driving motor 17 keeps driving the blade 221 to rotate, the blade 2 The dilute sulfuric acid flowing out of 21 can be evenly dispersed into the desulfurization and decyanation waste liquid under the stirring of the blade 221. In addition, by controlling the electromagnetic sheet 274 to adsorb the U-shaped frame 272 to slide up and down, the drive motor 17 can drive the worm 261 to rotate forward and reverse through the bevel gear shaft 27, so that the worm 261 drives the traction rod 25 to rotate forward and reverse through the worm gear 26, so that the traction rod 25 reels and releases the fiberglass rope 251, so that the fiberglass rope 251 pulls the blade 221 to slide up and down along the rotating rod 21, thereby causing the dilute sulfuric acid sprayed from the liquid outlet 222 on the lower end surface of the blade 221 to diffuse vertically in the reaction tank, thereby improving the uniformity of the distribution of the dilute sulfuric acid in the reaction tank, further reducing the problem of local over-acidity, reducing the risk of sulfide and cyanide rapidly decomposing into highly toxic gases under strong acid, suppressing the concentrated release of reaction heat, preventing the destruction of the stability of the catalyst, and maintaining the system temperature and pressure within the normal reaction range, thereby promoting the formation of target products such as elemental sulfur.

[0040] During the process of conveying dilute sulfuric acid, the user controls the external air heater to heat the compressed air, so that the heated air is conveyed to the gas distributor 16 at the bottom of the reaction tank through the air inlet 15, so that the gas distributor 16 disperses the heated compressed air into tiny bubbles, so that the tiny bubbles rise upward from the bottom of the reaction tank due to buoyancy. During the rising process of the bubbles, the oxygen in the bubbles serves as a reactant for the oxidation reaction, and promotes the reaction through gas-liquid contact. When it is necessary to stop conveying dilute sulfuric acid, it is only necessary to control the solenoid valve 246 in the airway 245 to open. At this time, part of the compressed air entering the air inlet 15 flows into the groove 24 through the airway 245, so that the compressed air entering the groove 24 The air will flow to the L-shaped hole 244. In the initial state, the end of the L-shaped hole 244 away from the airway 245 is blocked by the wall of the groove 24, so that the L-shaped hole 244 is in a closed state at this time, so that the compressed air ejected from the airway 245 is located between the blocking plate 241 and the wall of the groove 24, so that the air pressure of the compressed air between the blocking plate 241 and the wall of the groove 24 is continuously increased, so that the blocking plate 241 is pushed by the compressed air and squeezes the support spring 242 to move away from the airway 245, so that the blocking plate 241 drives the through hole 243 on the surface to cross the infusion port 12, so that the blocking plate 241 drives the L-shaped hole 244 on the surface to pass through the infusion port 12 and the annular groove 21. 1 is connected, so that the compressed air delivered by the airway 245 enters the liquid outlet 222 through the infusion port 12, the annular groove 211 and the spring hose 212, so that the dilute sulfuric acid remaining in the infusion port 12, the annular groove 211, the spring hose 212 and the liquid outlet 222 is pushed into the reaction tank by the compressed air, thereby reducing the waste of dilute sulfuric acid. When the dilute sulfuric acid remaining in the infusion port 12, the annular groove 211, the spring hose 212 and the liquid outlet 222 is completely pushed into the reaction tank, the solenoid valve 246 is controlled to close. The reason why the groove 24 and the baffle plate 241 connected to the infusion port 12 are provided instead of installing the solenoid valve 246 in the infusion port 12 is because the infusion port 12 delivers The dilute sulfuric acid will corrode the solenoid valve 246, affecting the use effect and service life of the solenoid valve 246. The groove 24 and the baffle plate 241 are provided to make the dilute sulfuric acid directly contact with the baffle plate 241, avoiding the dilute sulfuric acid from contacting the solenoid valve 246, that is, ensuring that the baffle plate 241 can effectively block the dilute sulfuric acid delivered by the infusion port 12, and also ensuring the normal and stable use of the solenoid valve 246. Similarly, by providing a bellows 29 on the surface of the rotating rod 21, the bellows 29 can protect the glass fiber rope 251, the spring hose 212 and the rotating rod 21, thereby ensuring the use effect of the glass fiber rope 251, the spring hose 212 and the rotating rod 21 and improving their service life.

[0041] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for removing dissolved sulfur from desulfurization and decyanation wastewater, characterized in that: The following steps are involved: S1: First, pre-treat the desulfurization and decyanation waste liquid to remove suspended particles, floating oil and other insoluble substances, then pump the pre-treated desulfurization and decyanation waste liquid into the reaction tank, and add ferric chloride as a catalyst into the reaction tank. Control the reaction temperature at 60-90 ° C and the reaction pressure at 0.1-0.3 MPa. Then, add 10% dilute sulfuric acid into the reaction tank in batches to maintain the pH value of the solution in the reaction tank in the range of 2-4. S2: When the pH value of the solution in the reaction tank is lower than 4, compressed air is introduced into the reaction tank. The compressed air temperature is 60-80°C and the reaction time is 2-5 hours. S3: The gaseous products generated during the reaction are directly transported to the absorption tower through the exhaust port (11) above the reaction tank. The waste liquid at the bottom of the reaction tank is pumped into a centrifuge after the reaction is completed, so that the centrifuge filters the sulfur particles in the waste liquid. The centrifuged waste liquid is then transported to a transfer tank. S4: Before the centrifuged waste liquid is transported to the transfer tank, activated carbon is filled into the transfer tank so that the organic sulfur compounds in the waste liquid poured into the transfer tank are adsorbed by the activated carbon, and finally a liquid without dissolved sulfur is obtained.

2. The method for removing dissolved sulfur from desulfurization and decyanation wastewater according to claim 1, wherein: In S1, dilute sulfuric acid with a concentration of 10% is added three times, the temperature of the first addition of dilute sulfuric acid is 55-60°C, the temperature of the second addition of dilute sulfuric acid is 65-75°C; and the temperature of the third addition of dilute sulfuric acid is 75-85°C.

3. The method for removing dissolved sulfur from desulfurization and decyanation wastewater according to claim 2, wherein: In S2, during the first addition of dilute sulfuric acid, compressed air at 55-60°C is first introduced. After reacting for 10-20 minutes, the temperature of the introduced compressed air is controlled to slowly rise to 65-75°C. After the second addition of dilute sulfuric acid, the temperature of the introduced compressed air is controlled to slowly rise to 75-85°C.

4. The method for removing dissolved sulfur from desulfurization and decyanation wastewater according to claim 1, wherein: The reaction tank comprises a tank body (1); the tank body (1) is provided with an exhaust port (11), a liquid inlet (12), a liquid inlet (13), a liquid outlet (14) and an air inlet (15) in sequence from top to bottom; a gas distributor (16) connected to the air inlet (15) is installed at the bottom of the tank body (1); a mounting plate (2) is fixedly installed inside the tank body (1); a rotating rod (21) is rotatably connected to the lower end of the mounting plate (2); a rotating ring (22) is slidably connected to the surface of the rotating rod (21); a blade (221) is fixedly connected to the surface of the rotating ring (22); a cavity (23) is provided inside the mounting plate (2); and mutually A bevel gear ring (231) and a bevel gear shaft (232) are meshed; the bevel gear ring (231) is fixedly connected to the upper end of the rotating rod (21); a driving motor (17) is installed on one side of the tank body (1); the bevel gear shaft (232) is fixedly connected to the output shaft of the driving motor (17); a liquid outlet (222) is provided on the surface of the blade (221); an annular groove (211) is provided on the surface of the rotating rod (21) and is communicated with the infusion port (12); the annular groove (211) and the liquid outlet (222) are connected via a spring hose (212); a blocking unit is installed in the mounting plate (2); the blocking unit is used to block the infusion port (12); A traction unit is installed inside the tank body (1); the traction unit is used to pull the swivel (22) to slide up and down along the rotating rod (21).

5. The method for removing dissolved sulfur from desulfurization and decyanation wastewater according to claim 4, characterized in that: The blocking unit comprises a blocking plate (241); a groove (24) communicating with the infusion port (12) is provided inside the mounting plate (2); the blocking plate (241) is slidingly and sealingly connected in the groove (24); the group partition plate is connected to the bottom of the groove (24) via a supporting spring (242); a through hole (243) is provided on the surface of the blocking plate (241); an L-shaped hole (244) is provided at one end of the blocking plate (241); an air passage (245) communicating with the air inlet (15) is provided at one end of the groove (24) near the L-shaped hole (244); and a solenoid valve (246) is installed in the air passage (245).

6. The method for removing dissolved sulfur from desulfurization and decyanation wastewater according to claim 5, characterized in that: The traction unit comprises a traction rod (25); a glass fiber rope (251) is fixedly connected to the upper end of the rotating ring (22); the end of the glass fiber rope (251) away from the rotating ring (22) passes through the center of the rotating rod (21) and is connected to the surface of the traction rod (25); the output shaft of the drive motor (17) and the traction rod (25) are connected via a transmission unit.

7. The method for removing dissolved sulfur from desulfurization and decyanation wastewater according to claim 6, characterized in that: The transmission unit comprises a worm wheel (26) and a worm (261); a bevel gear ring (233) is installed on the end of the bevel gear shaft (232) away from the rotating rod (21); the worm wheel (26) is fixedly connected to the traction rod (25); the worm (261) is rotatably connected to the outer wall of the tank body (1); a bevel gear shaft (27) is provided on the side of the worm wheel (26) away from the worm (261); two bevel gear shafts (27) are provided; a sliding groove (271) is provided on the outer wall of the tank body (1); the sliding groove A U-shaped frame (272) is slidably connected in the groove (271); the U-shaped frame (272) is connected to the upper end wall of the slide groove (271) via a connecting spring (273); the two bevel gear shafts (27) are rotatably connected to the two ends of the U-shaped frame (272); the rotating rod (21) is located between the two bevel gear shafts (27); the two bevel gear shafts (27) are connected to the worm (261) through a transmission belt (275); and an electromagnetic sheet (274) is embedded in the upper end wall of the slide groove (271).

8. The method for removing dissolved sulfur from desulfurization and decyanation wastewater according to claim 7, characterized in that: The inner wall of the transmission belt (275) is provided with a tooth groove (276); the surfaces of the bevel gear shaft (27) and the worm (261) are both fixedly connected with a spur gear ring (28); the spur gear ring (28) is slidably connected to the tooth groove (276) on the inner wall of the transmission belt (275).

9. The method for removing dissolved sulfur from desulfurization and decyanation wastewater according to claim 8, characterized in that: The surface of the rotating rod (21) is sleeved with a bellows (29); one end of the bellows (29) is fixedly connected to the rotating rod (21), and the other end is fixedly connected to the rotating ring (22); the spring hose (212) and the bellows (29) are both made of PTFE material.

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