A method and device for recovering arsenic from high-arsenic smoke

Abstract

The invention discloses a method for recovering arsenic from high-arsenic smoke dust, wherein high-arsenic smoke dust and a carbon reducing agent are mixed to obtain a high-arsenic smoke dust mixed material, and the high-arsenic smoke dust mixed material is roasted in an inert or reducing atmosphere to obtain arsenic-containing tail gas and high-lead ash; the arsenic-containing tail gas is passed into a combustion furnace, and an activator is sprayed into the combustion furnace through a pulse powder spray valve for combustion to obtain high-temperature flue gas; the high-temperature flue gas is condensed to obtain arsenic trioxide. A device for recovering arsenic from high-arsenic smoke dust comprises a roasting furnace, a combustion furnace, a settling chamber, a dust collector, a spray tower, and an external exhaust chimney that are connected in sequence; the roasting furnace comprises a furnace and a continuous feeding device for introducing materials containing high-arsenic smoke dust into the furnace for roasting, and a mixing bin is arranged above the continuous feeding device. The dearsenication process of the invention has good dearsenication selectivity and stability, an arsenic removal efficiency of up to 96.0% or more, and the purity of the purified arsenide reaches more than 98.0%.

Description

Technical Field

[0001] The invention belongs to the technical field of comprehensive recycling of metallurgical solid wastes, and in particular relates to a method and a device for recovering arsenic from high-arsenic smoke. Background Art

[0002] High-arsenic smoke mainly comes from the roasting and smelting process of metal minerals such as copper, lead and zinc. Metals such as copper, lead and zinc are generally associated with arsenic. Arsenic cannot be completely removed during the beneficiation process. Therefore, a certain amount of arsenic will enter the smelting process with these metals and enter the smoke and smelting slag respectively. Arsenic in high-arsenic smoke exists in various forms, mainly in the form of oxides, arsenates, arsenides and a small amount of arsenic sulfide. Every year, a large amount of high-arsenic smoke is stored in the form of arsenic-containing tailings and tailings in the mining, selection and smelting of non-ferrous metals such as copper, lead and zinc in my country. A large amount of valuable metals cannot be recycled, resulting in resource waste, and solid waste containing a large amount of arsenide pollutes the soil environment and surface water, and even groundwater. If these arsenic-containing wastes are not handled in time or improperly handled, they will cause great harm to the ecological environment and human health. From both economic and environmental perspectives, the resource recovery and utilization of high-arsenic smoke is of great significance.

[0003] For the treatment of high arsenic smoke, the main processes currently used are leaching and roasting.

[0004] Arsenic removal by leaching is a method of selectively dissolving high-arsenic smoke in a leaching agent, transferring arsenic from the solid phase to the liquid phase, and finally removing it in the liquid phase. Roasting arsenic removal mainly recovers arsenic in the form of arsenic trioxide at high temperature, or reduces and refines crude arsenic trioxide to prepare elemental arsenic, thereby separating it from valuable metals. Arsenic removal by leaching includes alkaline leaching, acid leaching or other oxidant solution leaching. The arsenic leaching rate obtained by arsenic removal of high-arsenic smoke by alkaline leaching is not high, and the process requires high leaching temperature and high energy consumption. The pH value of the obtained leaching solution is high, and the subsequent treatment process is cumbersome and difficult. Acid leaching dissociates solid arsenic into water-soluble arsenate or arsenite ions, producing highly toxic metallurgical waste liquid. Although H 2 O 2 As(III) is oxidized to As(V), which is less toxic and more stable, but is greatly affected by temperature, resulting in H 2 O 2 Decomposition reduces its leaching rate. There are also problems such as the generation of highly toxic hydrogen arsenic gas, difficulty in filtration of leached residue, and low metal separation rate.

[0005] Generally, roasting to remove arsenic is directly applied to high-arsenic dust, but it cannot achieve a good separation of lead and arsenic (especially arsenic pentoxide, lead arsenate and arsenic sulfide). Chinese patent documents with application numbers CN201811200399.2 and CN201910713899.4 disclose direct oxidation roasting of high-arsenic dust, which has problems such as low arsenic removal rate, poor operating conditions, and serious environmental pollution. At the same time, Chinese patent document with application number CN201810943471.4 proposes to reduce and roast the arsenic-containing smoke, and then perform high-temperature membrane filtration to obtain refined white arsenic; Chinese patent document CN201811422941.9 proposes to mix the arsenic-containing smoke from copper smelting with iron sulfide, and roast it in a protective atmosphere to obtain arsenic trioxide; Chinese patent document CN201910380550.3 proposes to mix arsenic-containing copper smoke with coke powder and copper oxide powder and roast it to recover arsenic trioxide; Chinese patent document CN201410601278.4 proposes to mix a carbonaceous reducing agent (anthracite powder, charcoal powder) and a promoter (polyethylene glycol, diamyl phthalate) with arsenic-containing smoke to reduce and volatilize and separate arsenic, etc., all of which mention reduction roasting to remove arsenic, and then cooling to recover arsenic trioxide. However, during the reduction roasting process of arsenic-containing ash, some arsenic compounds (such as arsenic sulfide) and other substances (such as lead and zinc) that are easily volatile and have no time to react evaporate along with the flue gas, making it impossible to obtain a high-purity arsenic trioxide product, and it is also impossible to achieve the purpose of completely separating arsenic from valuable metals. Summary of the invention

[0006] The technical problem to be solved by the present invention is that, due to the high hazard and difficulty in separation of arsenic, arsenic compounds that do not have time to react in the general reduction roasting dearsenicization process, as well as lead and zinc compounds, will evaporate with the flue gas, and the purpose of completely separating arsenic trioxide from valuable metals cannot be achieved, and high-purity arsenic trioxide cannot be directly obtained.

[0007] In order to solve the above technical problems, the technical solution proposed by the present invention is: to provide a method for recovering arsenic from high-arsenic smoke, the process diagram is as follows Figure 1 As shown, the following steps are included:

[0008] (1) Mixing high-arsenic smoke and a carbon reducing agent to obtain a high-arsenic smoke mixture material, and roasting the high-arsenic smoke mixture material in an inert or reducing atmosphere to obtain arsenic-containing tail gas and high-lead ash; wherein, in terms of mass percentage, the main components of the high-arsenic smoke are: As 20-40%, Pb 20-40%, S2-7%; the roasting temperature is 700-800°C, and the roasting time is 0.5-3h; the high-lead residue is cooled in a roasting furnace, collected and sold.

[0009] (2) introducing the arsenic-containing tail gas into a combustion furnace, and spraying an activator into the combustion furnace through a pulse powder injection valve for combustion to obtain high-temperature flue gas; wherein the activator is one or more of sodium dodecyl sulfate, sodium lignin sulfonate, and hydroquinone; and the amount of the activator sprayed is 10 to 50 mg / m3 of the volume of the arsenic-containing tail gas. 3 The temperature of the combustion furnace is controlled at 500-700℃; natural gas and air are introduced as needed during the combustion process to provide heat for combustion;

[0010] (3) Condensing the high-temperature flue gas to obtain arsenic trioxide.

[0011] Preferably, a promoter is also added during the mixing process of step (1), and the promoter accounts for 0.2% to 1% of the mass of the high-arsenic smoke.

[0012] Preferably, the accelerator is one or both of limestone and lime, or a mixture of lime and aluminum oxide, and the particle size of the accelerator is 0.5-5 mm. 3 ), lime (CaO) mainly plays a role in desulfurization and can react with SO 2 The reaction produces calcium sulfite (CaSO 3 ) and calcium sulfate (CaSO 4 ), while CaCO 3 Thermal decomposition produces CO 2 , CO 2 Reacting with C to generate CO can provide an indirect reducing atmosphere for arsenide; moreover, Al 2 O 3 It can combine with CaO to form calcium aluminate (3CaO·Al 2 O 3 and 12CaO·7Al 2 O 3 ), during smelting, calcium aluminate and the desulfurization product CaS can be well combined together, and the effect of slag removal and desulfurization can be achieved.

[0013] Preferably, in step (1), during calcination, negative pressure is maintained, the pressure being: -0.3 kPa to -1 kPa.

[0014] Preferably, in step (1), the carbon reducing agent is at least one of biomass carbon powder, activated carbon powder, and petroleum coke powder; the particle size of the carbon reducing agent is 0.1 to 0.3 mm; and the carbon reducing agent accounts for 8% to 16% of the mass of the high-arsenic smoke.

[0015] Preferably, in step (2), the combustion time (residence time of the arsenic-containing tail gas in the combustion furnace) is 2-5 seconds.

[0016] Preferably, in step (3), the high-temperature flue gas is treated by a gravity settling chamber at the front end and a pulse bag filter at the rear end of the combined smoke purification device to obtain arsenic trioxide.

[0017] As the same inventive concept, the present invention also provides a device for recovering arsenic from high-arsenic smoke, including a roasting furnace, a combustion furnace, a settling chamber, a dust collector, a spray tower, and an external exhaust chimney connected in sequence; wherein the combustion furnace is provided with a pulse powder spray valve.

[0018] Furthermore, the roasting furnace comprises a furnace and a continuous feeding device for introducing materials containing high arsenic smoke into the furnace for roasting, and a mixing bin is arranged above the continuous feeding device.

[0019] Furthermore, the continuous feeding device comprises a steel belt for conveying high-arsenic smoke materials, and a sealing cover located above the steel belt, wherein the sealing cover is filled with a protective gas.

[0020] Furthermore, the sedimentation chamber is a gravity sedimentation chamber, and the dust collector is a bag dust collector.

[0021] Furthermore, the mixing bin comprises a batching bin located at the upper part and a distributor located at the lower part, wherein the distributor is filled with protective gas.

[0022] Furthermore, a spray device and a cold air valve are connected to the entrance of the gravity settling chamber.

[0023] Furthermore, a variable frequency fan is provided on the gas pipeline connecting the bag filter and the spray tower.

[0024] Furthermore, temperature meters are provided at the gas inlets of the gravity settling chamber and the bag filter.

[0025] The present invention adds 8% to 16% of carbon reducing agent (preferably 10%) and 0.2% to 1% of accelerator (preferably 0.5%) to the high-arsenic smoke raw material, which are measured by mass percentage, and are sent to the mixing bin for uniform mixing, and then enter the distributor from the batching bin, and the distributor is sealed and protected by nitrogen to make the material evenly distributed on the steel belt of the steel belt roasting furnace. The material is sealed and protected by a protective atmosphere (such as nitrogen) from the distribution device to the steel belt.

[0026] In a preferred embodiment, the working temperature (reduction roasting temperature) of the steel strip roasting furnace is 700-800°C, the preferred reduction roasting temperature is 750°C, the heating rate is 5-15°C / min, the holding time at the working temperature is 0.5-3h, preferably 2h; the negative pressure of the furnace body is -0.3-1kPa. As the steel strip runs, the high-arsenic smoke and dust mixture enters the furnace of the steel strip roasting furnace with good nitrogen sealing. In the furnace, the steel strip and the material above the steel strip are indirectly heated and heated by the electric heating wire outside the stainless steel furnace. After the material is heated, roasted and evaporated in a temperature zone with a nitrogen atmosphere or a reducing atmosphere, the arsenide in the material is evaporated and separated, and the high-lead ash is collected at the tail of the steel strip roasting furnace.

[0027] Preferably, the inert gas / protective atmosphere during the roasting process is industrial nitrogen with a purity of ≥99%.

[0028] Preferably, in order to purify and separate arsenic, a combustion furnace is set at the flue gas outlet of the steel strip roasting furnace, and an activator is sprayed into the furnace through a pulse powder injection valve. The temperature of the combustion furnace is controlled at 500-700°C, and the preferred combustion temperature is 650°C; the arsenic-containing flue gas stays in the combustion furnace for 2-5 seconds, and the preferred reaction time (the time the flue gas stays in the combustion furnace) is 3 seconds; the induced air volume of the steel strip roasting furnace is controlled at 1000-2000m 3 / h. The combustion furnace performs secondary combustion on the flue gas, converting all arsenic compounds (such as arsenic sulfide) in the flue gas into As 2 O 3 When the arsenic-containing vapor enters the gravity settling chamber, it is directly cooled to below 300°C by "spraying water mist + spraying cold air". After entering the front end of the combined smoke purification device (i.e., the gravity settling chamber), the temperature is further reduced to below 120°C, and finally enters the back end of the combined smoke purification device (i.e., the bag filter). Arsenic trioxide is collected in the combined smoke purification device, and the flue gas after dust removal is sent to the wet desulfurization tower by the fan. After the flue gas is desulfurized, it is discharged from the chimney to meet the standards, thereby achieving the recovery of As. 2 O 3 purpose.

[0029] In a more preferred embodiment, the preferred activator of the present invention can destroy the sulfide structure, increase the contact with oxygen, and further improve the purity and conversion rate of arsenic sulfide to arsenic trioxide. The amount of activator added is 10-50 mg / m 3 , preferably 20 mg / m 3 .

[0030] According to a preferred solution, when the arsenic-containing vapor enters the front end (i.e., gravity settling chamber) of the combined smoke purification device, since a spray device and a cold air valve are connected to the entrance of the gravity settling chamber, the flue gas temperature is precisely controlled by direct quenching through "water mist spray + cold air spray", and the arsenic-containing vapor is quenched to less than 300°C. After passing through the gravity settling chamber, the temperature of the cooled flue gas is further reduced to less than 120°C, and then enters the rear end (i.e., bag dust collector) of the combined smoke purification device.

[0031] Preferably, the flue gas after dust removal by the bag filter is sent to the wet flue gas desulfurization tower by the fan for washing, and the flue gas is discharged out of the chimney after desulfurization; the collected high-purity arsenic trioxide is further utilized, and the lead-rich ash is bagged and sold to the lead smelter.

[0032] Compared with the prior art, the advantages of the present invention are:

[0033] (1) The present invention adopts a three-stage arsenic removal process of reduction roasting-secondary oxidation-dust collection, which has good arsenic removal selectivity and stability. The arsenic removal efficiency in high-arsenic smoke is as high as 96.0% or more, and the purity of the purified arsenide reaches more than 98.0%. It also enriches lead-containing raw materials, comprehensively solves the environmental protection problem of arsenic in high-arsenic smoke, realizes the resource utilization, reduction and harmlessness of arsenic-containing smoke, and at the same time, the by-product high-lead ash is enriched.

[0034] (2) In the process of the present invention, the flue gas after roasting is subjected to secondary combustion and an activator is introduced. The combustion oxidation and the activator destroy the sulfide structure, enhance the oxidation of arsenide, and improve the conversion rate of arsenic trioxide, which also ensures that the process of the present invention is applicable to sulfur-containing high-arsenic flue gas.

[0035] (3) In the process of the present invention, limestone, lime, aluminum oxide, etc. are used as promoters, and the desulfurization ability of the promoters is utilized to improve the purity of arsenic trioxide.

[0036] (4) In the process of the present invention, the steel strip roasting furnace with nitrogen sealing protection is applicable to a wide range of arsenic-containing smoke (≥15%), and has the characteristics of large processing capacity, low impurity content, high dust collection rate, and small environmental impact.

[0037] (5) The present invention is connected to a spray device and a cold air valve at the entrance of the gravity settling chamber, and adopts a direct quenching method of spraying water mist + cold air, which can accurately and quickly control the low temperature conditions (≤300°C) for recovering arsenic-containing smoke and effectively collect arsenic-containing smoke.

[0038] (6) The present invention adopts a two-stage combined smoke dust purification device of a gravity settling chamber + a bag-type dust collector for graded dust collection. On the one hand, the gravity settling chamber can be used to further cool down, while reducing the load of high-temperature smoke on the bag-type dust collector, thereby ensuring the service life of the bag-type dust collector. On the other hand, the combination of the two can efficiently collect high-purity arsenic-containing smoke through double collection, which is easy to operate, has low pollution, and has a high recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 The figure is a flow chart of the method of the present invention.

[0041] Figure 2 Schematic diagram of the device of the present invention.

[0042] 1. Mixing silo; 2. Nitrogen tank; 3. Roasting furnace; 4. Pulse powder spray valve; 5. Combustion furnace; 6. Spray equipment; 7. Cold air valve; 8. Temperature meter; 9. Settling chamber; 10. Dust collector; 11. Variable frequency fan; 12. Spray tower; 13. External exhaust chimney.

[0043] Figure 3 This is the XRD diagram of high arsenic smoke raw material.

[0044] Figure 4 This is the XRD diagram of the purified arsenic trioxide of the present invention. DETAILED DESCRIPTION

[0045] In order to facilitate the understanding of the present invention, the present invention will be described in more comprehensive and detailed manner below in conjunction with the accompanying drawings and preferred embodiments of the specification, but the protection scope of the present invention is not limited to the following specific embodiments.

[0046] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0047] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0048] The present invention aims to efficiently separate arsenic and recover lead from high-arsenic smoke dust in industrial smelting, and to a certain extent solve the technical problems of difficult separation and low recovery rate in existing processes. To this end, the present invention provides a method for separating and purifying arsenic and recovering lead from high-arsenic smoke dust. Taking the high-arsenic smoke dust of a copper smelter as an example, the arsenic contained therein is mainly arsenic trioxide and lead arsenate, and the lead is mainly lead oxide and lead arsenate. The content of the main related components and the physical phase analysis are shown in Table 1 and Table 2. Taking advantage of the difference in the physical and chemical properties of the forms of lead and arsenic in the smoke, a carbon reducing agent and a promoter are added, placed in an inert or reducing atmosphere, and reduction roasted at 700-800°C under negative pressure conditions (especially for arsenates, negative pressure can efficiently collect evaporated smoke; secondly, it has little impact on the external environment, overcoming the shortcomings of traditional roasting processes that have a large impact on the environment), to separate the arsenic in the high-arsenic smoke, and enrich the lead in the ash for resource recovery and utilization; the arsenic-containing flue gas is then calcined in a combustion furnace to obtain arsenic trioxide with higher purity, and the arsenic-containing product is recovered through a two-stage dust collection process.

[0049] Table 1 Main ingredients of raw materials

[0050]

[0051] Table 2 XPS phase analysis of raw materials

[0052]

[0053]

[0054] Embodiment 1:

[0055] This embodiment provides a device for recovering arsenic from high-arsenic smoke, and its structural schematic diagram is shown in FIG. Figure 2 As shown: it includes a roasting furnace 3, a combustion furnace 5, a settling chamber 9, a dust collector 10, a spray tower 12, and an external exhaust chimney 13 which are connected in sequence; wherein the roasting furnace 3 includes a furnace and a continuous feeding device for introducing materials containing high arsenic smoke into the furnace for roasting, and a mixing bin 1 is arranged above the continuous feeding device.

[0056] The continuous feeding device includes a steel belt for conveying materials containing high-arsenic smoke, and a sealing cover located above the steel belt, the sealing cover is filled with protective gas, the mixing bin 1 includes a batching bin located at the upper part and a distributor located at the lower part, wherein the distributor is filled with protective gas, and the protective gas is nitrogen, which is provided by a nitrogen tank 2, and the mixing bin 1 and the roasting furnace 3 are both connected to the nitrogen tank 2.

[0057] The settling chamber 9 is a gravity settling chamber, and the dust collector 10 is a bag dust collector. The combustion furnace 5 is provided with a pulse powder injection valve 4 for injecting an activator, and the heat of the combustion furnace 5 is provided by natural gas combustion. The upper part of the settling chamber 9 is connected with a spray device 6 and a cold air valve 7, and a variable frequency fan 11 is provided on the gas pipeline connecting the dust collector 10 and the spray tower 12. The gas inlet of the settling chamber 9 and the dust collector 10 is provided with a temperature meter 8 for monitoring the temperature of the gas entering the settling chamber 9 and the dust collector 10.

[0058] Working principle: The material containing high arsenic smoke dust is batched in the batching bin of the mixing bin 1, and then enters the distributor at the bottom. The material containing high arsenic smoke dust falls onto the steel belt of the roasting furnace 3 under the protection of nitrogen, and is roasted in the roasting furnace 3. Among them, volatile components such as arsenide and sulfide enter the combustion furnace 5 from the top of the roasting furnace 3, and the activator is sprayed into the combustion furnace 5 by the pulse powder spraying valve 4. After mixing with the gas entering from the top of the roasting furnace 3, it is ignited and burned with natural gas, so that the sulfide is more fully oxidized. Then the mixed flue gas enters the settling chamber 9 from the top of the combustion furnace 5, and before entering the settling chamber 9, it is sprayed with water mist by the spraying device 6 and cold air is sprayed by the cold air valve 7, so that the flue gas is rapidly cooled and cooled, and then gravity sedimentation is carried out in the settling chamber 9, most of the dust is deposited, and the remaining dust in the flue gas is further removed by the dust collector 10. The flue gas is discharged from the dust collector 10 and enters the spray tower 12. The sulfide in the flue gas is absorbed by the spray liquid of the spray tower 12. At the same time, the flue gas is further cooled. The flue gas discharged from the spray tower 12 can meet the emission standards and be discharged from the external chimney 13.

[0059] Embodiment 2:

[0060] The main components of the high-arsenic smoke treated in this embodiment are, by mass percentage, As30.25%, Pb28.45%, Cu3.02%, Zn4.21%, S4.23%, Sb1.46% and Fe26.35%. The XRD data of the phase are as follows: Figure 3 shown.

[0061] The method for recovering arsenic from high-arsenic smoke in this embodiment adopts the device in Example 1 for recovery, and comprises the following steps:

[0062] 500kg of the above-mentioned smoke dust is mixed evenly with 50kg of activated carbon powder (10% of the smoke dust mass, particle size ≤0.15mm) and 2.5kg of limestone (0.5% of the smoke dust mass) in a mixing bin, and then enters the distributor. The nitrogen seal protects the distributor so that the material is evenly distributed on the steel belt of the steel belt roasting furnace. As the steel belt runs, the high-arsenic smoke dust mixture enters the furnace of the well-sealed steel belt electric heating evaporator, fills the furnace with nitrogen, and maintains the pressure in the furnace at -1kPa. The steel belt and the material above the steel belt are indirectly heated by the electric heating wire outside the stainless steel furnace and heated to 750℃. The heating and roasting time is 2h. After the material is heated, roasted and evaporated in a nitrogen atmosphere (industrial nitrogen, purity ≥99%), the arsenic in the material completes the evaporation and separation process. The evaporated tail gas is introduced into the combustion furnace, and the flue gas volume (the flow rate of arsenic tail gas) is controlled to be 2000m 3 / h, and at the same time, sodium dodecyl sulfate powder is sprayed into the combustion furnace through a pulse powder injection valve, and the injection amount of sodium dodecyl sulfate powder is 40g / h (that is, the injection amount of the activator is 20mg / m 3 ), the combustion temperature is controlled at 650℃ (combustion is ignited by natural gas), the reaction time is 3s (the residence time of flue gas in the combustion furnace), and the interval time of pulse powder liquid spraying is consistent with the residence time of flue gas in the combustion furnace. After combustion, the arsenic-containing vapor enters the settling chamber, and then passes through the spray equipment at the entrance of the settling chamber to spray water mist and the cold air valve to spray cold air, so that the flue gas is rapidly cooled to below 300℃. After entering the gravity settling chamber, the temperature is further reduced to below 120℃, and then the dust is removed by the bag dust collector. Arsenic-containing dust is collected at the bottom of the combined dust purification device of gravity settling chamber + bag dust removal. The flue gas is sent to the wet flue gas desulfurization tower by the fan, and the flue gas is discharged from the chimney to meet the standards after desulfurization.

[0063] Among them, the main chemical components of the residue after arsenic removal (in mass percentage) are As1.16%, Pb45.56%, Cu5.17%, Zn6.95%, Sb2.47%, and the arsenic removal rate reaches 96.17%; the purity of arsenic trioxide in the arsenic-containing smoke collected in the gravity settling chamber and the dust collector reaches 98.27%. The phase data are as follows Figure 4 shown.

[0064] Embodiment 3:

[0065] The main components of the high-arsenic smoke treated in this embodiment are, in mass percentage, As 25.46%, Pb 24.35%, Cu 3.14%, Zn 3.18%, S 2.06%, Sb 0.95% and Fe 26.26%.

[0066] The method for recovering arsenic from high-arsenic smoke in this embodiment adopts the device in Example 1 for recovery, and comprises the following steps:

[0067] 500kg of the above-mentioned smoke dust is mixed evenly with 60kg of biomass carbon powder (12% by mass of smoke dust, particle size ≤0.10mm) and 1.5kg of lime (0.3% by mass of smoke dust) in a mixing bin, and then enters the distributor. The nitrogen seal protects the distributor so that the material is evenly distributed on the steel belt of the steel belt roasting furnace. As the steel belt runs, the high-arsenic smoke dust mixture enters the furnace of the well-sealed steel belt electric heating evaporation furnace, fills the furnace with nitrogen, and maintains the pressure in the furnace at -0.6kPa. The steel belt and the material above the steel belt are indirectly heated to 700℃ by the electric heating wire outside the stainless steel furnace, and the heating and roasting time is 90min. After the material is heated, roasted and evaporated in a nitrogen atmosphere (industrial nitrogen, purity ≥99%), the arsenic in the material completes the evaporation and separation process. The evaporated arsenic-containing tail gas is introduced into the combustion furnace, and the amount of smoke introduced by the roasting furnace (i.e., the flow rate of arsenic-containing tail gas) is controlled to be 1500m 3 / h, and at the same time, sodium lignin sulfonate powder is sprayed into the combustion furnace through a pulse powder injection valve, and the injection amount of sodium lignin sulfonate powder is 30g / h (that is, the injection amount of the activator is 20mg / m 3 ), the combustion temperature is controlled at 700℃, and the reaction time is 2.5s. The arsenic-containing vapor after combustion enters the gravity settling chamber, and the water mist is sprayed by the spray equipment at the entrance of the gravity settling chamber, and the cold air is sprayed into the cold air valve. The flue gas is directly cooled to below 300℃ by "water mist + cold air" quenching. After entering the gravity settling chamber, the temperature is further reduced to below 120℃, and then the bag dust collector is used for dust removal. Arsenic-containing smoke is collected at the bottom of the combined smoke purification device of gravity settling chamber + bag dust removal. The smoke is sent to the wet flue gas desulfurization tower by the fan, and the smoke is discharged from the chimney to meet the standards after desulfurization.

[0068] The main chemical components of the residue after arsenic removal (in mass percentage) are As1.01%, Pb40.66%, Cu4.96%, Zn5.57%, Sb1.46%, and the arsenic removal rate reaches 96.03%; the purity of arsenic trioxide in the arsenic-containing flue dust collected in the gravity settling chamber and the dust collector reaches 98.33%.

[0069] Embodiment 4:

[0070] The main components of the high-arsenic smoke treated in this embodiment are, by mass percentage, As 34.67%, Pb 30.71%, Cu 3.25%, Zn 3.87%, S 5.13%, Sb 2.12% and Fe 25.46%.

[0071] The method for recovering arsenic from high-arsenic smoke in this embodiment adopts the device in Example 1 for recovery, and comprises the following steps:

[0072] 500kg of the above-mentioned smoke dust is mixed evenly with 75kg of petroleum coke powder (15% of the smoke dust mass, particle size ≤0.25mm), 1.0kg of aluminum oxide and 3kg of lime (0.8% of the smoke dust mass) in a mixing bin, and then enters the distributor. The nitrogen seal protects the distributor so that the material is evenly distributed on the steel belt of the steel belt roasting furnace. As the steel belt runs, the high-arsenic smoke dust mixed material enters the furnace of the well-sealed steel belt electric heating evaporation furnace, fills the furnace with nitrogen, and maintains the pressure in the furnace at -0.3kPa. The steel belt and the material above the steel belt are indirectly heated by the electric heating wire outside the stainless steel furnace and heated to 750℃. The heating and roasting time is 2h. After the material is heated, roasted and evaporated in a nitrogen atmosphere (industrial nitrogen, purity ≥99%), the arsenic in the material completes the evaporation and separation process. The evaporated tail gas is introduced into the combustion furnace, and the roasting flue gas volume (i.e., the flow rate of arsenic tail gas) is controlled to be 1000m 3 / h, and at the same time, hydroquinone powder is sprayed into the combustion furnace through the pulse powder injection valve, and the injection amount is 20g / h (that is, the injection amount of the activator is 20mg / m of the volume of the arsenic tail gas). 3 ), the combustion temperature is controlled at 650℃, and the reaction time is 3s. After combustion, the arsenic-containing vapor enters the settling chamber, and then passes through the spray equipment at the entrance of the gravity settling chamber to spray water mist and the cold air valve to spray cold air. After "spraying water mist + cold air" quenching, it is directly cooled to below 300℃. After entering the gravity settling chamber, the temperature is further reduced to below 120℃, and then enters the bag dust collector for dust removal. Arsenic-containing smoke is collected at the bottom of the combined smoke purification device of gravity settling chamber + bag dust removal. The flue gas is sent to the wet flue gas desulfurization tower by the fan, and the flue gas is discharged from the chimney to meet the standards after desulfurization.

[0073] The main chemical components of the residue after arsenic removal (in mass percentage) are As1.02%, Pb51.90%, Cu5.43%, Zn6.73%, Sb7.90%, and the arsenic removal rate reaches 97.06%; the purity of arsenic trioxide in the arsenic-containing smoke collected after combustion reaches 98.32%.

[0074] Comparative Example 1:

[0075] The main components of the high-arsenic smoke treated in this comparative example are, by mass percentage, As 34.67%, Pb 30.71%, Cu 3.25%, Zn 3.87%, S 5.13%, Sb 2.12% and Fe 25.46%.

[0076] The method for recovering arsenic from high-arsenic smoke in this comparative example comprises the following steps:

[0077] 500kg of the above-mentioned smoke dust is mixed evenly with 75kg of petroleum coke powder (15% of the smoke dust mass, particle size ≤0.25mm), and the materials are evenly distributed on the steel belt of the steel belt roasting furnace through the nitrogen-sealed protection distributor from the batching buffer silo. As the steel belt runs, the high-arsenic smoke dust mixture enters the furnace of the well-sealed steel belt electric heating evaporator, fills the furnace with nitrogen, and maintains the pressure in the furnace at -0.3kPa. The steel belt and the materials above the steel belt are indirectly heated to 750°C by the electric heating wire outside the stainless steel furnace, and the heating and roasting time is 2h. After the material is heated, roasted and evaporated in a nitrogen atmosphere (industrial nitrogen, purity ≥99%), the arsenic in the material completes the evaporation and separation process. The evaporated tail gas is introduced into the combustion furnace, and the amount of flue gas introduced into the roasting furnace (i.e., the flow rate of arsenic tail gas) is controlled to be 1000m 3 / h, and at the same time, hydroquinone is sprayed into the combustion furnace through the pulse powder injection valve, and the injection amount is 20g / h (that is, the injection amount of the activator is 20mg / m of the volume of the arsenic-containing tail gas). 3 ), the combustion temperature is controlled at 650℃, and the reaction time is 3s. After combustion, the arsenic-containing vapor enters the gravity settling chamber, and then passes through the spray equipment at the entrance of the gravity settling chamber to spray water mist and the cold air valve to spray cold air. After "spraying water mist + cold air" quenching, it is directly cooled to below 300℃. After entering the gravity settling chamber, the temperature is further reduced to below 120℃, and then enters the bag dust collector for dust removal. Arsenic-containing smoke is collected at the bottom of the combined smoke purification device of gravity settling chamber + bag dust removal. The flue gas is sent to the wet flue gas desulfurization tower by the fan, and the flue gas is discharged from the chimney to meet the standards after desulfurization.

[0078] The main chemical components of the residue after arsenic removal (in mass percentage) are As3.13%, Pb59.89%, Cu5.59%, Zn6.54%, Sb5.24%, and the arsenic removal rate reaches 90.97%; the purity of arsenic trioxide in the arsenic-containing smoke collected after combustion reaches 98.28%.

[0079] Comparative Example 2:

[0080] The main components of the high-arsenic smoke treated in this comparative example are, by mass percentage, As 25.46%, Pb 24.35%, Cu 3.14%, Zn 3.18%, S 2.06%, Sb 0.95% and Fe 26.26%.

[0081] The method for recovering arsenic from high-arsenic smoke in this comparative example comprises the following steps:

[0082] 500kg of the above-mentioned smoke dust is mixed evenly with 60kg of biomass carbon powder (12% by mass of smoke dust, particle size ≤0.10mm) and 1.5kg of lime (0.3% by mass of smoke dust), and the materials are evenly distributed on the steel belt of the steel belt roasting furnace through the nitrogen-sealed protection distributor from the batching buffer silo. As the steel belt runs, the high-arsenic smoke dust mixture enters the furnace of the well-sealed steel belt electric heating evaporator, fills the furnace with nitrogen, and maintains the pressure in the furnace at -0.6kPa. The steel belt and the materials above the steel belt are indirectly heated to 700℃ by the electric heating wire outside the stainless steel furnace, and the heating and roasting time is 90min. After the material is heated, roasted and evaporated in a nitrogen atmosphere (industrial nitrogen, purity ≥99%), the arsenic in the material completes the evaporation and separation process. The evaporated tail gas is introduced into the combustion furnace, and the amount of flue gas introduced by the roasting furnace (i.e., the flow rate of arsenic tail gas) is controlled to be 1500m 3 / h, the combustion temperature is controlled at 700℃, and the reaction time is 2.5s. The arsenic-containing vapor after combustion enters the settling chamber, and then passes through the spray equipment at the entrance of the settling chamber to spray water mist and the cold air valve to spray cold air. It is directly cooled to below 300℃ by "spraying water mist + cold air" quenching. After entering the gravity settling chamber, the temperature is further reduced to below 120℃, and then the bag dust collector is used for dust removal. Arsenic-containing smoke is collected at the bottom of the combined smoke purification device of gravity settling chamber + bag dust removal. The flue gas is sent to the wet flue gas desulfurization tower by the fan, and the flue gas is discharged from the chimney to meet the standards after desulfurization.

[0083] The main chemical components of the residue after arsenic removal (in mass percentage) are As1.02%, Pb40.67%, Cu4.95%, Zn5.58%, Sb1.47%, and the arsenic removal rate reaches 96.00%; the purity of arsenic trioxide in the arsenic-containing smoke collected in the gravity settling chamber and the dust collector reaches 95.43%.

[0084] In the above embodiments, a carbon reducing agent and a promoter are added to the high-arsenic smoke to reduce and roast the high-arsenic smoke, and the arsenic-containing smoke is then burned and oxidized. The arsenic removal rate of the high-arsenic smoke is greater than 96%, and the purity of the obtained arsenic trioxide is greater than 98%. Therefore, it can be considered that it is technically feasible to extract elemental arsenic by redox roasting of high-arsenic smoke.

Claims

1. A method for recovering arsenic from high-arsenic smoke, characterized in that: The following steps are involved: (1) mixing high-arsenic smoke and a carbon reducing agent to obtain a high-arsenic smoke mixture material, and roasting the high-arsenic smoke mixture material in an inert or reducing atmosphere to obtain arsenic-containing tail gas and high-lead ash; wherein, in terms of mass percentage, the main components of the high-arsenic smoke are: As 20-40%, Pb 20-40%, S2-7%; the roasting temperature is 700-800° C., and the roasting time is 0.5-3 h; (2) introducing the arsenic-containing tail gas into a combustion furnace, and spraying an activator into the combustion furnace through a pulse powder injection valve for combustion, the combustion time is 2-5 seconds, and high-temperature flue gas is obtained; wherein the activator is one or more of sodium dodecyl sulfate, sodium lignin sulfonate, and hydroquinone; the injection amount of the activator is 10-50 mg / m3 of the volume of the arsenic-containing tail gas. 3 ;The temperature of the combustion furnace is controlled at 500-700℃; (3) Condensing the high-temperature flue gas to obtain arsenic trioxide.

2. The method according to claim 1, characterized in that During the mixing process of step (1), a promoter is also added, and the promoter accounts for 0.2% to 1% of the mass of the high-arsenic smoke.

3. The method according to claim 2, characterized in that The accelerator is one or both of limestone and lime, or a mixture of lime and aluminum oxide; the particle size of the accelerator is 0.5-5 mm.

4. The method according to any one of claims 1 to 3, characterized in that In step (1), negative pressure is maintained during roasting, and the pressure is: -0.3kPa to -1kPa.

5. The method according to any one of claims 1 to 3, characterized in that: In step (1), the carbon reducing agent is at least one of biomass carbon powder, activated carbon powder, and petroleum coke powder; the particle size of the carbon reducing agent is 0.1-0.3 mm; and the carbon reducing agent accounts for 8%-16% of the mass of the high-arsenic smoke.

6. A device for the method of recovering arsenic from high-arsenic smoke according to any one of claims 1 to 5, characterized in that: The invention comprises a roasting furnace, a combustion furnace, a settling chamber, a dust collector, a spray tower and an external exhaust chimney which are connected in sequence; wherein the roasting furnace is provided with a pulse powder spraying valve.

7. The device according to claim 6, characterized in that The roasting furnace comprises a furnace and a continuous feeding device for introducing materials containing high arsenic smoke into the furnace for roasting, and a mixing bin is arranged above the continuous feeding device.

8. The device according to claim 7, characterized in that The continuous feeding device comprises a steel belt for conveying high-arsenic smoke materials and a sealing cover located above the steel belt, wherein the sealing cover is filled with protective gas.

9. The device according to any one of claims 6 to 8, characterized in that: The inlet of the settling chamber is connected with a spray device and a cold air valve.

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