阅读说明：本技术 一种从铜阳极泥中回收硒的回收装置和回收方法 (Recovery device and recovery method for recovering selenium from copper anode slime ) 是由 李栋 乔晋玺 许志鹏 郭学益 田庆华 于 2021-07-09 设计创作，主要内容包括：本发明公开了一种从铜阳极泥中回收硒的回收装置,包括：预处理系统,用于铜阳极泥破碎并与硫酸混合均匀得到预处理物料；焙烧-净化系统,用于焙烧预处理物料产生含二氧化硒及二氧化硫的烟气,并对烟气进行脱尘净化；吸收还原系统,用于吸收烟气并同步还原二氧化硒得到粗硒；所述预处理系统、焙烧-净化系统以及同步吸收还原系统依次连接。本发明还提供一种利用上述的回收装置从铜阳极泥中回收硒的回收方法。本发明的从铜阳极泥中回收硒的回收装置以及回收方法可有效的解决阳极泥回收硒过程中工艺复杂、成本高昂、硒回收率低、粗硒品位低等问题,最终硒的整体回收可达99％以上,粗硒品味达到98％以上。(The invention discloses a recovery device for recovering selenium from copper anode slime, which comprises: the pretreatment system is used for crushing the copper anode slime and uniformly mixing the copper anode slime with sulfuric acid to obtain a pretreated material; the roasting-purifying system is used for roasting the pretreated material to generate flue gas containing selenium dioxide and sulfur dioxide, and dedusting and purifying the flue gas; the absorption reduction system is used for absorbing the flue gas and synchronously reducing the selenium dioxide to obtain crude selenium; the pretreatment system, the roasting-purification system and the synchronous absorption reduction system are connected in sequence. The invention also provides a recovery method for recovering selenium from copper anode slime by using the recovery device. The recovery device and the recovery method for recovering selenium from copper anode slime can effectively solve the problems of complex process, high cost, low selenium recovery rate, low crude selenium grade and the like in the process of recovering selenium from anode slime, and finally the overall recovery of selenium can reach more than 99 percent and the grade of crude selenium can reach more than 98 percent.)

1. A recovery device for recovering selenium from copper anode slime is characterized by comprising:

the pretreatment system is used for crushing the copper anode slime and uniformly mixing the copper anode slime with sulfuric acid to obtain a pretreated material;

the roasting-purifying system is used for roasting the pretreated material to generate flue gas containing selenium dioxide and sulfur dioxide, and dedusting and purifying the flue gas;

the absorption reduction system is used for absorbing the flue gas and synchronously reducing the selenium dioxide to obtain crude selenium;

the pretreatment system, the roasting-purification system and the synchronous absorption reduction system are connected in sequence.

2. The recycling apparatus according to claim 1, wherein the roasting-cleaning system comprises a roasting furnace (1) arranged in a transverse direction, the roasting furnace (1) is provided with a feed port and an air outlet, a roasting area (101) for roasting generated flue gas is arranged in the roasting furnace (1) at a side close to the feed port, a paddle stirring device is arranged in the roasting area (101), a dedusting area (102) for dedusting flue gas is arranged in the roasting furnace (1) at a side close to the air outlet, a heat-resistant baffle system is arranged in the dedusting area (102), and the roasting area (101) is directly communicated with the dedusting area (102).

3. The recycling device according to claim 2, wherein the paddle stirring device comprises a plurality of arc-shaped blades (3), a central main shaft (4) and a driving component (5) for driving the central main shaft (4) to rotate, the central main shaft (4) is transversely arranged at the center of the roasting area (101), the arc-shaped blades (3) are arranged on the central main shaft (4), and the distance between the outer edges of the arc-shaped blades (3) and the inner wall of the roasting area (101) is 1-5 mm.

4. The recycling apparatus according to claim 2, wherein said heat-resistant baffle system comprises at least one first baffle (6) disposed at the bottom of the inner wall of said dust-removing region (102) and at least one second baffle (7) disposed at the top of the inner wall of said dust-removing region (102), a gap is disposed between the top of said first baffle (6) and the top of the inner wall of said dust-removing region (102), a gap is disposed between the bottom of said second baffle (7) and the bottom of the inner wall of said dust-removing region (102), and said first baffle (6) and said second baffle (7) are alternately arranged in sequence.

5. A recycling apparatus according to claim 2, characterized in that the roasting furnace (1) is provided with an air-entraining assembly (8) for introducing oxygen-enriched air into the roasting zone (101) on the side close to the charging opening.

6. A recycling apparatus according to any of claims 1 to 5, characterized in that the pretreatment system comprises a wet grinding device (9) and a screw extrusion conveyor (10) connected in series, the discharge of the screw extrusion conveyor (10) being connected to the roasting-scrubbing system.

7. The recycling apparatus according to any one of claims 1 to 5, wherein the absorption reduction system comprises a flue gas absorption tower (11) and a tail gas absorption tower (12) in sequence according to a gas flow direction, and a vacuum pump assembly (13) for controlling the air pressure in the flue gas absorption tower (11) and the tail gas absorption tower (12) is connected to the tail gas absorption tower (12).

8. The recycling device according to claim 7, wherein the gas inlet pipe of the flue gas absorption tower (11) or the tail gas absorption tower (12) extends to the bottom of the flue gas absorption tower (11) or the tail gas absorption tower (12), the tail end of the gas inlet pipe is a closed circular ring (14), a plurality of gas outlet holes (15) are uniformly formed in the circular ring (14), at least one grid plate (16) is further arranged above the circular ring (14), the grid plate (16) is provided with dividing holes (17), and the grid plate (16) is located below the liquid level of the absorption liquid.

9. A recovery device according to claim 7, characterized in that the outer wall of the flue gas absorption tower (11) is provided with a water cooling jacket (18) for controlling the temperature of the absorption liquid in the tower.

10. A recovery method for recovering selenium from copper anode slime using the recovery device of any one of claims 1 to 9, characterized by comprising the steps of:

s1: mixing copper anode mud and sulfuric acid according to a mass-volume ratio of 1: (0.5-3) adding the copper anode slime into a pretreatment system, crushing the copper anode slime, and uniformly mixing the copper anode slime with sulfuric acid to obtain a pretreatment material;

s2: adding the pretreated materials into a roasting-purifying system, and sequentially heating and roasting in the following modes: the temperature rise is divided into 5 stages, the temperature of each stage is respectively 250-350 ℃, 350-450 ℃, 450-550 ℃, 550-600 ℃ and 600-650 ℃, the temperature is respectively kept for 1-2h in each stage, and the flue gas containing selenium dioxide and sulfur dioxide is generated in the roasting process;

s3: and when the temperature rise roasting is started in S2, the absorption reduction system is synchronously started to absorb the flue gas and synchronously reduce the selenium dioxide to obtain crude selenium, and the negative pressure value in the absorption reduction system is controlled to be-6000 Pa to-14000 Pa.

Technical Field

The invention belongs to the technical field of metallurgy, and particularly relates to a selenium recovery device and a selenium recovery method.

Background

Selenium is one of rare and dispersive metals and is widely applied to the fields of metallurgy, glass, ceramics, electronics, solar energy, feed and the like. For example, selenium is used as an antioxidant additive in the electrolytic manganese industry, and accounts for more than 60% of the total selenium. In the glass industry, the optical properties and color of glass can be changed by adding small amounts of selenium. In the chemical industry, selenium is mainly used as a pigment ingredient and a substitute for a vulcanizing agent in rubber production. With the development of science and technology, selenium is increasingly widely applied in the high-tech field, and the manufacture of semiconductor devices, thermoelectric devices, solar cells, laser devices, infrared light guide materials and the like is the future application direction of selenium. The global independent selenium deposit is only one place in Enshi City, and the detected selenium with exploitation value reaches 45.7 tons. At present, selenium is mainly recovered from byproducts in the copper smelting process, particularly, copper anode slime is mainly used, and the selenium source accounts for about 90% of selenium resources required by the market.

At present, the main technologies for recovering selenium from copper anode slime include a pyrogenic roasting process and a wet leaching process. For example, patent CN11607698A discloses a method for treating copper anode slime, which includes mixing copper anode slime with first concentrated sulfuric acid, reacting, filtering to obtain decoppered residue, mixing the decoppered residue with concentrated sulfuric acid to obtain slurry, performing a roasting selenium steaming process, reacting selenide in the slurry with sulfuric acid to generate selenate, decomposing the selenate into selenium dioxide and volatilizing the selenium dioxide into flue gas, and decomposing excess sulfuric acid to generate sulfur dioxide and introducing the sulfur dioxide into the flue gas. Experiments show that the selenium content in the selenium steaming slag is less than 0.5%, the flue gas is washed by two stages of dynamic waves to recover crude selenium, the recovery rate of the whole selenium in the process is only 90-95%, and the recovery rate needs to be improved. Hanjunhong et al use muffle furnace as main equipment, and the copper anode mud is processed by processes of sulfating roasting selenium steaming-acid leaching copper removing, etc., so that the selenium volatilization rate can reach 99.7%, and the crude selenium taste can reach 93.6%. Lihuajian researches the influence of microwave heating on copper anode slime sulfating roasting selenium removal, and the comprehensive selenium removal rate can reach 96.12%. In the above laboratory researches such as handsfree and li huajian, the selenium removal rate of the copper anode slime is much higher than that in the production practice, but from the whole process, the laboratory lab research still has many details which cannot be considered, and the operation of part of the laboratory can not be completely realized in the industrial practice, and from the laboratory technology to the industrial practice application, a large amount of work needs to be completed.

The Kennycott company in America adopts a full-wet process, anode mud is subjected to sulfuric acid oxygen pressure leaching for decoppering, sodium chlorate, chlorine and hydrogen peroxide are added into obtained decoppering slag to be subjected to chlorination leaching, gold and selenium in the anode mud are leached into a solution, and H is used for removing copper₂AuCl₄，H₂SeO₃The solution rich in gold and selenium is subjected to a solvent extraction process, elemental gold is extracted into an organic phase, selenium is left in a water phase, and sulfur dioxide is introduced to reduce and precipitate to obtain a crude selenium product. The recovery rate of the selenium in the full-wet process can reach 96%, and the grade of the crude selenium is higher. However, the method has the disadvantages of complicated equipment, large medicament consumption, large amount of waste water and high investment cost, and is difficult to realize large-scale industrialization.

In summary, the methods and devices for recovering selenium from copper anode slime disclosed in the prior art all have the problems of complex process, high cost, large amount of waste water and waste residue, low selenium recovery rate, low crude selenium grade and the like, and a method and a device for recovering selenium from copper anode slime with high efficiency and industrial application are urgently needed to be developed.

Disclosure of Invention

The invention aims to overcome the defects and shortcomings in the background art and provide a recovery device and a recovery method for recovering selenium from copper anode slime, which have the advantages of simple process, low cost, industrialized application and high selenium recovery rate and grade. In order to solve the technical problems, the technical scheme provided by the invention is as follows:

a recovery device for recovering selenium from copper anode slime comprises:

the pretreatment system is used for crushing the copper anode slime and uniformly mixing the copper anode slime with sulfuric acid to obtain a pretreated material;

the roasting-purifying system is used for roasting the pretreated material to generate flue gas containing selenium dioxide and sulfur dioxide, and dedusting and purifying the flue gas;

the absorption reduction system is used for absorbing the flue gas and synchronously reducing the selenium dioxide to obtain crude selenium;

the pretreatment system, the roasting-purification system and the synchronous absorption reduction system are connected in sequence.

In the above recovery device, preferably, the roasting-purifying system includes a roasting furnace arranged transversely, the roasting furnace is provided with a feed port and an air outlet, one side of the roasting furnace close to the feed port is provided with a roasting region for roasting to generate flue gas, the roasting region is provided with a paddle stirring device, one side of the roasting furnace close to the air outlet is provided with a dust-removing region for removing dust from the flue gas, the dust-removing region is provided with a heat-resistant baffle system, and the roasting region is directly communicated with the dust-removing region.

The feed inlet of the roasting furnace is connected with the discharge outlet of the pretreatment system, and specifically, the discharge outlet of the spiral extrusion conveying device can directly introduce the pretreatment materials into the roasting area. The feed inlet and the gas outlet of the roasting furnace can be positioned at two ends of the roasting furnace, one side of the roasting furnace close to the feed inlet is a roasting area, and one side of the roasting furnace close to the gas outlet is a dust removal area. The outer wall of the roasting furnace can be provided with a heating furnace sleeve for providing heat for the roasting furnace, so that the temperature in the furnace is regulated and controlled, and a high-temperature environment is provided. The roasting furnace can be internally provided with 3 temperature detection points which are respectively positioned in the heating furnace sleeve, the roasting area and the air outlet. The temperature rise of the furnace sleeve is monitored in real time by setting a program for temperature rise of a heating furnace sleeve supporting facility, the actual temperature in the furnace is concerned, and the reaction temperature is based on the temperature in the furnace. The gas temperature at the gas outlet needs to be noticed in the selenium steaming process, the outlet temperature is not lower than 450 ℃, and the selenium dioxide gas is ensured not to be cooled and separated out in the subsequent process, so that the loss of selenium is caused. The roasting furnace can be internally provided with an air pressure detection point for displaying the air pressure in the furnace. The roasting furnace can be internally provided with a maintenance port which is arranged below the dedusting area and used for treating accumulated smoke after long-time production.

In the above recycling device, preferably, the paddle stirring device includes a plurality of arc-shaped blades, a central main shaft and a driving component for driving the central main shaft to rotate, the central main shaft is transversely disposed at the center of the roasting region, the plurality of arc-shaped blades are disposed on the central main shaft in a staggered manner, and the distance from the outer edges of the arc-shaped blades to the inner wall of the roasting region is 1-5 mm. The structure can ensure that the slurry can rotate at a low speed in the roasting area, avoid long-time positioning sintering of the slurry, ensure that the slurry is stripped from the inner wall of the roasting area, and avoid the phenomenon of kiln caking.

In the above recycling apparatus, preferably, the heat-resistant baffle system includes at least one first baffle disposed at the bottom of the inner wall of the dust-removing area and at least one second baffle disposed at the top of the inner wall of the dust-removing area, a gap is provided between the top of the first baffle and the top of the inner wall of the dust-removing area, a gap is provided between the bottom of the second baffle and the bottom of the inner wall of the dust-removing area, and the first baffle and the second baffles are alternately arranged in sequence. More preferably, the first baffle is arranged in the dust removing area and adjacent to the roasting area so as to prevent the materials from moving to the dust removing area. The flue gas entering the dust removal area from the roasting area freely passes through the dust removal area, and floating dust is settled in the baffle box under the blocking of the multiple first baffles and the multiple second baffles due to the influence of gravity, so that the flue gas purification effect is achieved, and the grade of the product selenium is finally improved.

In the above recycling apparatus, preferably, an air-entraining component for introducing oxygen-enriched air into the roasting region is disposed on a side of the roasting furnace close to the charging port. The gas filling assembly comprises an oxygen cylinder and an air pump. Oxygen-enriched air is slowly introduced into the furnace, so that the oxygen partial pressure in the furnace can be improved, the oxidation of selenium and selenium-containing compounds is converted, meanwhile, partial simple substances and low-valence substances in the anode mud can be oxidized, the sintering risk in the roasting process is effectively reduced, and in addition, the introduced oxygen-enriched air can drive the flue gas in the furnace to enter a subsequent flue gas sedimentation and absorption reduction system.

In the above recycling apparatus, preferably, the pretreatment system includes a wet grinding device and a screw extrusion material conveying device, which are connected in sequence, and a discharge port of the screw extrusion material conveying device is connected to the roasting-purifying system. The discharge port of the wet grinding device is connected with the material conveying pipeline of the valve, and batch discharge can be realized through the gravity action. The wet grinding device crushes and grinds the materials through grinding and simultaneously generates a stirring effect, and the materials and the sulfuric acid are uniformly mixed, so that the homogenization of the anode mud is realized. The screw of the screw extrusion conveying device provides strong extrusion, shearing and stirring effects for the high-viscosity mixed material filled in the machine barrel in the high-speed rotating process, so that the mixed material is further fully mixed and activated.

In the above recovery device, preferably, the absorption reduction system sequentially includes a flue gas absorption tower and a tail gas absorption tower in a gas flow direction, and the tail gas absorption tower is connected with a vacuum pump assembly for controlling air pressure in the flue gas absorption tower and the tail gas absorption tower. The absorption tower can be cast and molded by special alloy and can stably run under the conditions of 10-20% concentration mixed acid, 80-90 ℃ and negative pressure of-10000 Pa. The vacuum pump assembly comprises a negative pressure buffer tank, a pressure regulator and a vacuum pump. Through setting up vacuum pump subassembly, can guarantee that the flue gas in the roasting furnace continues to flow to the absorption reduction system in the furnace chamber, reduces the interior selenium dioxide steam pressure of stove, improves and evaporates selenium efficiency. Above-mentioned vacuum pump subassembly and air entrainment subassembly cooperation, the effect is more excellent.

Among the above-mentioned recovery unit, preferably, the flue gas absorption tower or the intake pipe of tail gas absorption tower all to the flue gas absorption tower or the bottom of tail gas absorption tower extends, just the end of intake pipe is closed ring, a plurality of ventholes have evenly been seted up on the ring, the top of ring still is equipped with an at least net board, be equipped with the segmentation hole (like 3mm) on the net board, the net board is located below the absorption liquid level. Set the end of intake pipe to the ring and set up the grid plate and all be favorable to getting into the gaseous dispersion of absorption tower, cut apart into the microbubble with big bubble, increase gas-liquid area of contact improves the absorption efficiency to selenium dioxide.

In the above recovery device, preferably, a water cooling jacket for controlling the temperature of the absorption liquid in the tower is provided on the outer wall of the flue gas absorption tower. Along with the continuous operation of system, high temperature flue gas constantly passes through the flue gas absorption tower, can lead to the interior liquid phase temperature of flue gas absorption tower to rise, and the high temperature can lead to selenium dioxide reduction reaction to be difficult to go on, has wrapped up in the water-cooling jacket in flue gas absorption tower periphery, can regulate and control the interior liquid phase temperature of flue gas absorption tower, guarantees the normal clear of selenium dioxide reduction reaction. A temperature measuring rod can be arranged in the flue gas absorption tower to monitor the temperature of the solution in the flue gas absorption tower in real time.

As a general technical concept, the present invention also provides a method for recovering selenium from copper anode slime by using the above recovery device, comprising the steps of:

s1: mixing copper anode mud and sulfuric acid according to a mass-volume ratio of 1: (0.5-3) adding the copper anode slime into a pretreatment system, crushing the copper anode slime, and uniformly mixing the copper anode slime with sulfuric acid to obtain a pretreatment material;

s2: adding the pretreated materials into a roasting-purifying system, and sequentially heating and roasting in the following modes: the temperature rise is divided into 5 stages, the temperature of each stage is respectively 250-350 ℃, 350-450 ℃, 450-550 ℃, 550-600 ℃ and 600-650 ℃, the temperature is respectively kept for 1-2h in each stage, and the flue gas containing selenium dioxide and sulfur dioxide is generated in the roasting process;

s3: and when the temperature rise roasting is started in S2, the absorption reduction system is synchronously started to absorb the flue gas and synchronously reduce the selenium dioxide to obtain crude selenium, and the negative pressure value in the absorption reduction system is controlled to be-6000 Pa to-14000 Pa.

Specifically, the recovery method comprises the following steps:

s1: adding the copper anode mud material and a proper amount of sulfuric acid into a pretreatment system, starting a wet grinding device to break the anode mud large particles, and simultaneously fully mixing the anode mud large particles with the sulfuric acid to be uniformly distributed. After grinding materials are ground for a certain time, stopping the wet grinding device, opening a discharge valve, putting the mixed materials into a spiral extrusion conveying device, and enabling pretreated materials treated by the device to enter a roasting area from a feed inlet of a roasting-purifying system;

s2: and after the pretreated material enters the roasting area, starting a heating furnace sleeve, and setting a program for heating. The long shaft of the control center of the driving assembly is started to drive the arc-shaped blade to rotate at a low speed, so that the phenomenon that the slurry is positioned and sintered for a long time to cause material wall bonding is avoided. And simultaneously, starting the air-entrapping assembly and introducing oxygen-enriched air into the roasting furnace.

S3: and opening a vacuum pump set at the tail end of the absorption reduction system after the roasting zone starts to operate, controlling the negative pressure value of the absorption tower within a certain range, and ensuring that gas in the furnace continuously enters the absorption reduction system after being purified by the dust removal zone. The high negative pressure can ensure that the gas in the furnace continuously leads to a recovery system, reduce the vapor pressure of the selenium dioxide gas in the furnace and effectively improve the selenium steaming efficiency.

More specifically, the recovery method comprises the following steps:

s1: adding the copper anode mud material and sulfuric acid into a wet grinding device, and controlling the volume mass ratio of the added sulfuric acid to the copper anode mud material to be (0.5-3): 1. after the materials and the sulfuric acid are added into a wet grinding device, a power supply is turned on, wet grinding is carried out for 3-5 hours, the materials are fully ground to form smaller particles, and meanwhile, the materials and the sulfuric acid are fully mixed. The material after wet grinding enters a roasting area through a screw extrusion conveying device, and the screw extrusion conveying device utilizes the rotation process of a screw to generate strong extrusion, shearing and stirring effects on the material and the barrel wall, so that the material is further mixed and activated. The slurry after the homogeneous mixing activation is favorable to the equilibrium of reaction going on among the calcination process, reduces large granule parcel and the insufficient phenomenon of calcination, and the calcination reaction can fully go on simultaneously, and gas production process makes the slag sample more tiny and granule homogeneous, is favorable to subsequent noble metal to retrieve.

S2: after the slurry obtained by the S1 treatment enters a roasting area, the temperature of the heating furnace jacket is controlled to be raised in 5 stages, the temperature control ranges are respectively 250-350 ℃, 350-450 ℃, 450-550 ℃, 550-600 ℃ and 600-650 ℃, the temperature is kept for 1-2h in each stage, and the specific heat preservation time needs to be specifically adjusted by combining the amount of the one-time treatment material. And adjusting the driving assembly to enable the rotating speed to be 1rpm, and ensuring that the arc-shaped blades slowly rotate at a constant speed along with the central long shaft. The distance between the arc-shaped blade and the inner wall of the roasting area is about 1-5mm, so that the slurry can be stripped from the inner wall of the roasting area as far as possible, and the kiln caking phenomenon is avoided. The oxygen cylinder and the air pump are connected to the roasting area, oxygen-enriched air is slowly introduced into the furnace, the air volume per minute is controlled to be 5-10% of the volume of the roasting area, the oxygen-enriched air is introduced to improve the oxygen partial pressure in the furnace, the oxidation of selenium and selenium-containing compounds is converted, meanwhile, partial simple substances and low-valence substances in the anode mud can be oxidized, the sintering risk in the roasting process is effectively reduced, and in addition, the oxygen-enriched air is introduced to drive the gas in the furnace to enter a subsequent flue gas sedimentation and gas synchronous absorption reduction system through the generator.

The selenium is evaporated out by roasting the slurry mixed by the copper anode mud and the sulfuric acid in the roasting zone, and the reaction in the furnace is shown as the following formula:

Ag₂Se+4H₂SO₄＝Ag₂SO₄+4H₂O+3SO₂↑+SeO₂↑；

Cu₂Se+6H₂SO₄＝2CuSO₄+6H₂O+4SO₂↑+SeO₂↑；

Cu+2H₂SO₄＝CuSO₄+2H₂O+SO₂↑；

2Cu+O₂＝2CuO；

2Ag+2H₂SO₄＝Ag₂SO₄+2H₂O+SO₂↑。

selenide and sulfuric acid in the copper anode mud generate selenium dioxide gas under the high-temperature condition to be removed from slag, metal simple substances react with the sulfuric acid to generate metal sulfate and sulfur dioxide, and the sulfur dioxide generated in each reaction can provide an effective reducing agent for a back-end process.

S3: and starting the operation in the roasting area, and opening a vacuum pump assembly at the tail end of the absorption reduction system after the heating furnace sleeve and the gas filling assembly start to work. The vacuum degree in the whole system is controlled by observing the air pressure detector, and the vacuum pump works intermittently, so that the negative pressure value in the absorption tower is in the range of-6000 Pa to-14000 Pa. Can ensure that the smoke in the furnace continuously flows from the furnace chamber to the absorption reduction system, reduce the steam pressure of the selenium dioxide in the furnace and improve the selenium steaming efficiency.

The smoke in the furnace continuously moves to the rear end under the double conditions of ventilation to the furnace and negative pressure operation, and the effect of separating gas from floating dust is achieved after the smoke passes through a dust removing area. The absorption reduction system comprises a flue gas absorption tower and a tail gas absorption tower, gas in the furnace enters the flue gas absorption tower through a gas guide pipe after being purified and dedusted, and the gas is directly communicated to the bottom of the absorption tower through the gas guide pipe and is positioned below the liquid level of absorption liquid. The gas guide pipe is terminal to be the ring form and spirals at the bottom of the absorption tower, trompil around the ring, increase the venthole, add simultaneously and be equipped with a plurality of net boards in the absorption tower, gaseous passing through the net board after letting in liquid and blockking to increase dwell time in solution, the while big bubble is cut apart into the bobble, has increased gas-liquid area of contact, more does benefit to going on of reaction, and then increases the absorption rate of selenium and the reduction rate of crude selenium. Along with the continuous operation of system, high temperature gas constantly passes through the absorption tower, returns and leads to the interior liquid phase temperature of absorption tower to rise, and the high temperature can lead to the selenium dioxide reduction reaction to be difficult to go on, has wrapped up in the water-cooling jacket in absorption tower periphery, can back regulation and control the interior liquid phase temperature of absorption tower, guarantees the normal clear of selenium dioxide reduction reaction.

The absorption tower structure can greatly improve the absorption efficiency of gas, greatly improve the reduction reaction, ensure that selenium dioxide and sulfur dioxide generated in the system can fully react, greatly improve the recovery rate of selenium, and reduce the investment of equipment cost compared with the traditional process. The selenium dioxide gas enters an absorption reduction system after passing through a flue gas sedimentation system, and reacts with sulfur dioxide gas generated at the same time in an aqueous solution to generate elemental selenium, and the reaction principle is shown as the following formula:

SeO₂+H₂O＝H₂SeO₃；

H₂SeO₃+2SO₂+H₂O＝Se↓+2H₂SO₄。

from the reaction formula, it is important to ensure the evaporation rate of selenium dioxide and the purity of selenium dioxide gas in order to obtain a high-quality selenium product. Meanwhile, enough sulfur dioxide gas is necessary, so that selenium absorbed into the water solution is reduced into elemental selenium, and the overall yield of the selenium is improved.

In summary, in the present invention, the pretreatment system comprises ball milling and extrusion material delivery, which can enhance the mixing of the raw materials, make the later reaction more sufficient, and greatly improve the recovery rate of selenium. Compare in traditional compounding device, this system can reach the same compounding degree in the short time, the whole process time that significantly reduces. Compared with the traditional roasting furnace, the roasting-purifying system has the advantages that the structure is improved, and the roasting-purifying system has the following advantages: 1. the arc-shaped blades are added in the roasting area, so that the materials can be effectively disturbed, the risk of kiln caking is greatly reduced, the reaction progress degree is improved, nearly 100% of selenium can be completely evaporated, and the selenium recovery rate is improved; 2. the dust removal area can effectively purify selenium dioxide steam, dust impurities are prevented from entering a rear-end process, and the grade of crude selenium is reduced. The improvement of absorption reduction system to the absorption tower structure, the bottom annular is ventilated, can increase gas-liquid reaction area of contact, makes the reaction go on more fully, increases the graticule and can cut the bubble, makes the inside gaseous abundant release of bubble, and increase reaction area of contact makes the two-phase contact of gas-liquid more abundant, increases gaseous dwell time simultaneously, further makes the reaction go on more thoroughly. Compared with the traditional process, the investment cost of the absorption tower can be reduced, and the production efficiency is improved. In addition, the absorption tower is additionally provided with a water cooling jacket, so that the liquid temperature is lower than a threshold value in the gas absorption process, and the reaction can be normally and continuously carried out.

Compared with the prior art, the invention has the advantages that:

the recovery device and the recovery method for recovering selenium from copper anode slime can effectively solve the problems of complex process, high cost, large amount of waste water and waste residues, low selenium recovery rate, low crude selenium grade and the like in the process of recovering selenium from anode slime, achieve the effects of reducing the process cost and simplifying the working procedures, and can be applied industrially, finally the overall recovery of selenium can reach more than 99%, and the crude selenium taste can reach more than 98%.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a recovery device for recovering selenium from copper anode slime according to the present invention (water cooling jacket is not shown in the figure).

FIG. 2 is a schematic structural view of a screw extrusion feeder according to the present invention.

Fig. 3 is a schematic structural view of a flue gas absorption tower and a tail gas absorption tower of the present invention.

FIG. 4 is a schematic diagram of the structure of the water jacket of the present invention.

Illustration of the drawings:

1. roasting furnace; 101. a roasting zone; 102. a dust removal zone; 2. heating a furnace sleeve; 3. an arc-shaped blade; 4. a central main shaft; 5. a drive assembly; 6. a first baffle plate; 7. a second baffle; 8. a gas adding assembly; 9. a wet milling device; 10. a screw extrusion material conveying device; 11. a flue gas absorption tower; 12. a tail gas absorption tower; 13. a vacuum pump assembly; 14. a circular ring; 15. an air outlet; 16. a grid plate; 17. dividing the hole; 18. a water cooling jacket.

Detailed Description

In order to facilitate an understanding of the invention, the invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of the invention is not limited to the specific embodiments below.

Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.

Example 1:

as shown in fig. 1, the recovery apparatus for recovering selenium from copper anode slime of the present embodiment includes:

the pretreatment system is used for crushing the copper anode slime and uniformly mixing the copper anode slime with sulfuric acid to obtain a pretreated material;

the roasting-purifying system is used for roasting the pretreated material to generate flue gas containing selenium dioxide and sulfur dioxide, and dedusting and purifying the flue gas;

the absorption reduction system is used for absorbing the flue gas and synchronously reducing the selenium dioxide to obtain crude selenium;

the pretreatment system, the roasting-purification system and the synchronous absorption reduction system are connected in sequence.

In this embodiment, the roasting-purifying system includes a roasting furnace 1 arranged transversely, a feed inlet and an air outlet are arranged on the roasting furnace 1, a roasting region 101 for producing flue gas by roasting is arranged on one side of the roasting furnace 1 close to the feed inlet, a paddle stirring device is arranged in the roasting region 101, a dust-removing region 102 for removing dust from the flue gas is arranged on one side of the roasting furnace 1 close to the air outlet, a heat-resistant baffle system is arranged in the dust-removing region 102, and the roasting region 101 is directly communicated with the dust-removing region 102. The outer wall of the roasting furnace 1 is provided with a heating furnace sleeve 2, and a temperature detection device and an air pressure detection device can be selectively arranged.

In this embodiment, the paddle stirring device includes a plurality of arc-shaped blades 3 (4 blades are shown in fig. 1), a central main shaft 4 and a driving component 5 for driving the central main shaft 4 to rotate, the central main shaft 4 is transversely disposed at the center of the roasting region 101, the arc-shaped blades 3 are disposed on the central main shaft 4, and the distance from the outer edges of the arc-shaped blades 3 to the inner wall of the roasting region 101 is 1-5mm (any of the above ranges).

In this embodiment, the heat-resistant baffle system includes at least one (2 shown in fig. 1) first baffle 6 disposed at the bottom of the inner wall of the dust-removing area 102 and at least one (2 shown in fig. 1) second baffle 7 disposed at the top of the inner wall of the dust-removing area 102, a gap is provided between the top of the first baffle 6 and the top of the inner wall of the dust-removing area 102, a gap is provided between the bottom of the second baffle 7 and the bottom of the inner wall of the dust-removing area 102, the first baffle 6 and the second baffle 7 are sequentially and alternately arranged, and the first baffle 6 is disposed at the joint of the baking area 101 and the dust-removing area 102.

In this embodiment, an air-adding component 8 for inputting oxygen-enriched air into the roasting area 101 is arranged on one side of the roasting furnace 1 close to the charging opening. The gas-filling assembly 8 comprises an oxygen cylinder and an air pump.

In this embodiment, the pretreatment system comprises a wet grinding device 9 and a screw extrusion conveyor 10 (the specific structure is shown in fig. 2) which are connected in sequence, and the discharge port of the screw extrusion conveyor 10 is connected with the roasting-cleaning system.

In this embodiment, the absorption reduction system sequentially includes a flue gas absorption tower 11 and a tail gas absorption tower 12 according to a gas flowing direction, and the tail gas absorption tower 12 is connected with a vacuum pump assembly 13 for controlling air pressure in the flue gas absorption tower 11 and the tail gas absorption tower 12. The vacuum pump assembly 13 includes a negative pressure buffer tank, a pressure regulator and a vacuum pump.

As shown in fig. 3, in this embodiment, the air inlet pipe of the flue gas absorption tower 11 or the tail gas absorption tower 12 extends toward the bottom of the flue gas absorption tower 11 or the tail gas absorption tower 12, the tail end of the air inlet pipe is a closed circular ring 14, a plurality of air outlet holes 15 are uniformly formed in the circular ring 14, at least one (2 pieces shown in fig. 1) grid plate 16 is further disposed above the circular ring 14, the grid plate 16 is provided with dividing holes 17, and the grid plate 16 is located below the liquid level of the absorption liquid.

As shown in fig. 4, in this embodiment, a water jacket 18 for controlling the temperature of the absorption liquid in the flue gas absorption tower 11 is provided on the outer wall of the tower.

The method for recovering selenium from copper anode slime by using the recovery device comprises the following steps:

s1: copper anode mud and sulfuric acid are mixed according to the mass volume ratio of (0.5-3): 1, adding the copper anode slime into a pretreatment system, crushing the copper anode slime, and uniformly mixing the copper anode slime with sulfuric acid to obtain a pretreatment material;

s2: adding the pretreated materials into a roasting-purifying system, and sequentially heating and roasting in the following modes: the temperature rise is divided into 5 stages, the temperature of each stage is respectively 250-350 ℃, 350-450 ℃, 450-550 ℃, 550-600 ℃ and 600-650 ℃, the temperature is respectively kept for 1-2h in each stage, and the flue gas containing selenium dioxide and sulfur dioxide is generated in the roasting process;

s3: and when the temperature rise roasting is started in S2, the absorption reduction system is synchronously started to absorb the flue gas and synchronously reduce the selenium dioxide to obtain crude selenium, and the negative pressure value in the absorption reduction system is controlled to be-6000 Pa to-14000 Pa.

Specifically, the method for recovering selenium from copper anode slime by using the recovery device in the embodiment includes the following steps:

mixing copper anode mud and sulfuric acid in a proportion of 1: adding the mixture into a wet grinding device 9 according to the volume mass ratio of 1, grinding for 3h, opening a discharge port valve, adding the mixture into a spiral extrusion conveying device 10, conveying the uniformly mixed slurry to a roasting area 101 after the spiral extrusion conveying device 10 is extruded and conveyed, starting a heating furnace sleeve 2 to control the temperature in the furnace, controlling the temperature to be stabilized at 270 ℃, 400 ℃, 500 ℃, 580 ℃ and 650 ℃ in 5 sections, simultaneously starting a tail end vacuum pump assembly 13, observing the pressure in a negative pressure buffer tank to be about-12000 Pa, and controlling the gas cylinder ventilation rate of a gas filling assembly 8 to be about 10% of the volume/min of the roasting area. And (3) after the system runs for a period of time, opening the water cooling jacket 18, and controlling the liquid phase temperature of the flue gas absorption tower 11 to be lower than 85 ℃. The stable production is carried out under the condition, and the result shows that the recovery rate of selenium in the anode mud reaches 99.7 percent, and the grade of crude selenium reaches 98.5 percent.

Example 2:

the recovery apparatus of this example was the same as in example 1.

The method for recovering selenium from copper anode slime by using the recovery device comprises the following steps:

mixing copper anode mud and sulfuric acid in a ratio of 0.7: 1 volume mass ratio is added into a wet grinding device 9, a discharge port valve is opened after grinding for 4 hours, a mixed material is added into a screw extrusion material conveying device 10, the screw extrusion material conveying device 10 conveys the uniformly mixed slurry to a roasting area 101 after extrusion conveying, a heating furnace sleeve 2 is started to control the temperature in the furnace, 5 sections of the temperature are controlled to be stabilized at about 300 ℃, 390 ℃, 450 ℃, 570 ℃ and 650 ℃, a tail end vacuum pump assembly 13 is started simultaneously, the pressure in a negative pressure buffer tank is observed to be about-8000 Pa, and the gas cylinder ventilation rate of a gas filling assembly 8 is controlled to be about 15% of the volume/min of the roasting area. And (3) after the system runs for a period of time, opening the water cooling jacket 18, and controlling the liquid phase temperature of the flue gas absorption tower 11 to be lower than 75 ℃. The stable production is carried out under the condition, and the result shows that the recovery rate of selenium in the anode mud reaches 99.6 percent, and the grade of crude selenium reaches 98.3 percent.

Example 3:

the recovery apparatus of this example was the same as in example 1.

The method for recovering selenium from copper anode slime by using the recovery device comprises the following steps:

mixing copper anode mud and sulfuric acid in a proportion of 2: adding the mixture into a wet grinding device 9 according to the volume mass ratio of 1, grinding for 3h, opening a discharge port valve, adding the mixture into a spiral extrusion conveying device 10, conveying the uniformly mixed slurry to a roasting area 101 after the spiral extrusion conveying device 10 is extruded and conveyed, starting a heating furnace sleeve 2 to control the temperature in the furnace, controlling the temperature to be stabilized at about 250 ℃, 350 ℃, 450 ℃, 585 ℃ and 620 ℃ in 5 sections, simultaneously starting a tail end vacuum pump assembly 13, observing the pressure in a negative pressure buffer tank to be about-14000 Pa, and controlling the gas cylinder ventilation rate of a gas filling assembly 8 to be about 10% of the volume/min of the roasting area. And (3) after the system runs for a period of time, opening the water cooling jacket 18, and controlling the liquid phase temperature of the flue gas absorption tower 11 to be lower than 85 ℃. The stable production is carried out under the condition, and the result shows that the recovery rate of selenium in the anode mud reaches 99.8 percent, and the grade of crude selenium reaches 98.8 percent.

Comparative example 1:

the experimental conditions in this comparative example were the same as in example 1 except that the copper anode slime was mixed with sulfuric acid at a ratio of 5: adding the mixture into a wet grinder according to the volume mass ratio of 1, and opening a discharge port valve after grinding for 4 hours. The result shows that the recovery rate of selenium in the anode mud reaches 51.4 percent, and the grade of crude selenium reaches 98.3 percent.

Comparative example 2:

the experimental conditions in this comparative example were the same as those in example 1 except that the pressure in the negative pressure buffer tank was controlled to about-3000 Pa (i.e., the pressures in the flue gas absorption column 11 and the tail gas absorption column 12). The result shows that the recovery rate of selenium in the anode mud reaches 80.4 percent, and the grade of crude selenium reaches 98.2 percent.

Comparative example 3:

the experimental conditions in this comparative example were the same as those in example 1 except that the selenium-containing gas absorption column was not provided with the water jacket 18. The result shows that the recovery rate of selenium in the anode mud reaches 90.4 percent, and the grade of crude selenium reaches 98.1 percent. Part of the selenium is not reduced and remains in solution.

Comparative example 4:

the experimental conditions in this comparative example were the same as those in example 1 except that the calcination-purification system used a conventional calcination furnace and the curved blade 3 and the dust-removal zone 102 were not provided. The result shows that the recovery rate of selenium in the anode mud is 97.8 percent, and the grade of crude selenium is 83.2 percent.

Comparative example 5:

the experimental conditions in this comparative example were the same as those in example 1 except that the selenium-containing gas absorption column did not use the annular aeration and mesh plate 16. The results show that the recovery rate of selenium in the anode mud is 82.5%, and the grade of crude selenium is 98.5%. Part of the selenium is precipitated in the tail gas absorption tower 12, and the single-stage absorption tower cannot completely absorb the selenium-containing gas.