Rotary kiln treatment system and treatment method for zinc-containing dust sludge

Abstract

The invention discloses a rotary kiln treatment system and method for zinc-containing dust and sludge, and belongs to the technical field of industrial solid waste treatment. The system comprises a batching system and a roasting system, the batching system is used for mixing raw materials and conveying the mixed raw materials to the rotary kiln; the roasting system comprises an automatic roasting temperature control system and a high-temperature section position control system, the automatic roasting temperature control system is used for adjusting the roasting temperature, and the high-temperature section position control system is used for adjusting the position of the roasting section. The roasting temperature can be adjusted according to the production condition, and the roasting effect is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of industrial solid waste treatment, and more specifically, relates to a rotary kiln treatment system and method for zinc-containing dust sludge. Background Art

[0002] In the metallurgical field, a large amount of steel is produced every year for various industrial fields. It is estimated that 600 to 800 kg of solid waste is generated per ton of steel, and a large amount of solid waste is generated every year. Among them, the iron-containing dust and mud, such as blast furnace gas mud (ash), converter and electric furnace dust removal ash, contain high levels of zinc. The stacking of zinc-containing dust and mud will not only cause environmental pollution, but also reduce the utilization rate of iron raw materials and affect economic benefits. If it is directly used in the process, it is easy to cause zinc enrichment, endangering the production safety of the blast furnace and affecting the sintering benefits.

[0003] At present, in order to solve the problem of zinc dust, many enterprises adopt pyrometallurgical roasting process to deal with zinc dust. As one of the pyrometallurgical processes for extracting zinc and selecting iron from zinc dust in steel, the rotary kiln roasting production process has the advantages of mature process, low investment cost and simple equipment operation compared with the coexisting rotary hearth furnace and other processes. The working process of the rotary kiln roasting production line is to mix the dust with high zinc content in the steel plant with coke powder and auxiliary materials in a certain proportion and send them into the rotary kiln for roasting. The materials entering the rotary kiln move parabolically from the kiln tail to the kiln head with the rotation of the rotary kiln body. The volatile metal oxides such as zinc and lead in the materials are reduced to metal vapor by coke powder and the carbon monoxide generated by it at 1050-1250℃. The metal vapor enters the dust collection process with the flue gas of the rotary kiln and is re-oxidized into metal oxides and collected. The smoke collected by the dust collection equipment such as the oxidation settling chamber, the surface cooler (waste heat boiler), and the bag dust collector is the secondary zinc oxide product of different grades. The other flue gas meets the emission standards after the dust removal and desulfurization process. Other non-volatile oxides in the material will form kiln slag, which will be returned to the smelting production line or other refining processes after water quenching or dry granulation.

[0004] However, the current level of automation control in rotary kiln roasting process is generally low, the raw material system is mostly extensive crane or loading truck mixing, and the workers have a poor working environment. At the same time, the stability of rotary kiln roasting is closely related to the kiln master's kiln firing level. The roasting temperature control depends on the kiln master's judgment of the fire, and production failures caused by human factors often occur.

[0005] The Chinese patent application number is CN201610737311.5, and the patent document with the publication date of February 1, 2017 discloses a method for treating high-zinc iron-containing dust and mud using a rotary kiln, wherein blast furnace gas ash and converter OG mud are mixed and pelletized; wet pellets are dried and preheated, and the drying and preheating heat source is the hot air generated by the high-temperature flue gas of the rotary kiln through a high-low temperature composite air heat exchanger; a granular coal spray gun, a residual carbon spray gun and a granular ore spray gun are arranged at the kiln head of the rotary kiln to spray high-volatile coal, residual carbon and high-grade iron ore into the kiln; the dried pellets are sent to the rotary kiln, and after direct reduction and high-temperature consolidation in the rotary kiln, high-temperature metallized pellets are obtained; the metallized pellets and excess residual carbon and other materials are cooled to room temperature and magnetically separated to obtain metallized pellets; the high-temperature flue gas leaving the rotary kiln is subjected to large-particle dust removal, then enters the high-low temperature composite air heat exchanger for cooling, and then enters the bag filter to recover zinc oxide powder.

[0006] The Chinese patent application number is: CN201910431667.X, and the patent document with the publication date of August 6, 2019 discloses a method for producing secondary zinc oxide by treating blast furnace dust with oxygen, comprising the following steps: batching: mixing blast furnace dust, sedimentation powder, and return powder in a ratio of 5:4:1 to obtain a mixture; controlling the water content in the mixture to be 12-18% by mass; and then using a disc granulating device to prepare the mixture into 6-12 mm particles. The solid waste particles are then pelletized and dried to keep the moisture content at 8-12%. The wet solid waste particles are sent to a rotary kiln for roasting, and the temperature at the kiln head is controlled at 1300-1600°C and the temperature at the kiln tail is controlled at 600-800°C. The ratio of the material amount to the kiln volume is 0.3:1-0.6:1. Compressed air with an oxygen concentration of 33-47% is introduced into the rotary kiln from the kiln head and the kiln tail for roasting for 2-3 hours. After the roasting is completed, the kiln tail air blowing pipe is closed and the secondary zinc oxide is collected.

[0007] Both of the above schemes are processes for treating zinc-containing solid waste through a rotary kiln. However, in actual treatment, Scheme 1 did not achieve the best treatment effect for the specific temperature control during the rotary kiln roasting. On the one hand, Scheme 2 treats blast furnace smoke and is not suitable for the treatment of zinc-containing dust mud. On the other hand, it also did not achieve the best treatment effect for the specific temperature control during the rotary kiln roasting. Summary of the invention

[0008] 1. Problems to be solved

[0009] In view of the problem that it is difficult to accurately control the specific roasting temperature in the existing rotary kiln treatment process of zinc-containing dust and sludge, resulting in unsatisfactory roasting effect, the present invention provides a rotary kiln treatment system and method for zinc-containing dust and sludge, which can adjust the roasting temperature according to production conditions and improve the roasting effect.

[0010] 2. Technical solution

[0011] To solve the above problems, the present invention adopts the following technical solutions.

[0012] A rotary kiln processing system for zinc dust sludge comprises a batching system and a roasting system; the batching system is used for mixing raw materials and then conveying them to the rotary kiln; the roasting system comprises a roasting temperature automatic control system and a high temperature section position control system, the roasting temperature automatic control system is used for adjusting the roasting temperature, and the high temperature section position control system is used for adjusting the position of the roasting section.

[0013] As a further improvement of the technical solution, the batching system includes a storage unit, a quantitative feeding unit and a mixing unit which are connected in sequence; the storage unit includes a dry ash bin for storing dry ash, a receiving trough for storing water-containing ash and a sludge bin for storing metallurgical mud; the quantitative feeding unit is arranged at the discharge port of the storage unit to control the quantitative transportation of the material; the mixing unit is used to stir the material evenly.

[0014] As a further improvement of the technical solution, the quantitative feeding system includes an ash unloading valve and a fully sealed belt scale installed at the outlet of the dry ash bin, a screw feeder and a belt scale installed at the outlet of the receiving trough, a hydraulic slide, a double screw feeder and a plunger pump installed at the outlet of the sludge bin, and an embedded scraper conveyor installed at the outlet of the fully sealed belt scale and the belt scale; the mixing unit includes a mixer installed at the outlet of the embedded scraper conveyor and the plunger pump.

[0015] As a further improvement of the technical solution, the roasting temperature automatic control system includes a kiln head auxiliary heating facility; the kiln head auxiliary heating facility includes a burner connected to the gas supply pipeline and a combustion-supporting fan connected to the burner, an outlet shut-off valve is installed on the pipeline between the combustion-supporting fan and the burner, and a gas shut-off valve and a gas regulating valve are installed on the gas supply pipeline.

[0016] As a further improvement of the technical solution, the roasting temperature automatic control system also includes a roasting section temperature measuring facility, and the roasting section temperature measuring facility is a wireless temperature measuring thermocouple for measuring the roasting temperature.

[0017] As a further improvement of the technical solution, the high-temperature section position control system includes a blower for blowing air at the kiln head of the rotary kiln, an infrared detection facility for the outer wall temperature of the rotary kiln for monitoring the kiln skin temperature, a main exhaust fan for adjusting the main exhaust volume of the rotary kiln and the system negative pressure, and a flame imaging system for monitoring the roasting conditions in the rotary kiln.

[0018] A method for treating zinc dust and sludge in a rotary kiln, comprising the steps of controlling the sum of heat input of the rotary kiln to be 1500-1800 kcal; the heat input of the rotary kiln includes the heat brought in by the carbon in the raw materials and the heat brought in by the auxiliary heating facilities at the kiln head, which is calculated by the following formula:

[0019]

[0020] Q 煤气 =q 煤气 ×L 煤气 ;

[0021] Among them, 393.5 is the enthalpy of burning 1g of carbon element into CO2; Q C The heat brought by the carbon in the raw material; Q i is the mass fraction of a certain raw material in the unit mixture; C di is the carbon content in a certain raw material; Q 煤气 The heat generated by the gas consumed by the unit mixture; q 煤气 is the calorific value of gas; L 煤气 The amount of gas consumed per unit mixture.

[0022] As a further improvement of the technical solution, the roasting temperature of the rotary kiln is controlled by the following formula:

[0023]

[0024] Among them, T 焙烧 is the roasting temperature; T0 is the initial temperature of the mixture; c 窑渣 is the specific heat capacity of slag; m 窑渣 The weight of slag generated per unit mixture.

[0025] As a further improvement of the technical solution, when the roasting temperature is between 1130℃ and 1180℃, the control system maintains the existing production status; when the roasting temperature exceeds 1130℃ to 1180℃ and is between 1100℃ and 1200℃, the heat input is adjusted through the kiln head auxiliary heating facilities to adjust the roasting temperature to between 1130℃ and 1180℃; when the roasting temperature exceeds 1100℃ to 1200℃, the roasting temperature is adjusted by both the kiln head auxiliary heating facilities and the batching system's ingredients.

[0026] As a further improvement of the technical solution, the rotary kiln is divided into a drying section, a preheating section, a high-temperature section and a cooling section from the kiln tail to the kiln head, and the high-temperature section is the main reaction section where zinc is reduced and precipitated; the temperature of the high-temperature section is set to 1100°C to 1200°C, the length of the high-temperature section is 1 / 3 to 2 / 3 of the total length of the kiln body, and the roasting end point is 0.45m to 0.55m away from the kiln head retaining ring.

[0027] 3. Beneficial effects

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The present invention provides a rotary kiln treatment system and method for zinc dust sludge. By setting a rotary kiln batching control system, all dust removal ash, carbon powder and powdered auxiliary materials are pumped into the dry ash elevated ash bin by a suction tank truck, thereby avoiding the dust problem during the dry ash transportation process, improving the on-site environment and reducing the labor intensity of workers.

[0030] (2) A rotary kiln treatment system and method for zinc dust sludge of the present invention can realize uniform quantitative feeding of raw materials by arranging corresponding feeding devices and feeding devices at the lower part of the raw material storage bin;

[0031] (3) The present invention provides a rotary kiln treatment system and method for zinc dust sludge, which can evenly mix various raw materials and fuels by setting a mixing facility, ensuring that the carbon and iron in the raw materials are fully and evenly distributed in the mixture, thereby reducing the problem of rotary kiln ringing caused by local high carbon and high iron;

[0032] (4) The present invention provides a rotary kiln treatment system and method for zinc dust sludge, which can realize automatic control of the rotary kiln roasting temperature and reduce production accidents of the rotary kiln by setting a kiln head auxiliary heating system and a rotary kiln roasting temperature detection and feedback facility;

[0033] (5) The present invention provides a rotary kiln treatment system and method for zinc-containing dust sludge. By setting a rotary kiln high-temperature section position control system, the high-temperature roasting zone of the rotary kiln can be effectively controlled, the recovery rate of metals such as lead and zinc can be improved, the output can be increased, and the pressure of the subsequent dust removal process can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a process flow chart of the present invention;

[0035] Figure 2 It is a control principle diagram of the rotary kiln batching system of the present invention;

[0036] Figure 3 It is a configuration diagram of the rotary kiln temperature control system of the present invention;

[0037] Figure 4 The present invention is a flow chart of rotary kiln temperature control;

[0038] Figure 5 It is a configuration diagram of the rotary kiln high temperature section position control system of the present invention;

[0039] Figure 6 This is a schematic diagram of the position control principle of the high temperature section of the rotary kiln of the present invention.

[0040] In the figure: 1. Batching system; 1.1. Dry ash; 1.2. Dry ash bin; 1.3. Ash discharge valve; 1.4. Fully sealed belt scale; 1.5. Buried scraper conveyor; 1.6. Water-containing ash; 1.7. Receiving trough; 1.8. Screw feeder; 1.9. Belt scale; 1.10. Metallurgical mud; 1.11. Sludge bin; 1.12. Hydraulic slide; 1.13. Double screw feeder; 1.14. Plunger pump; 1.15. Mixer; 2. Roasting system; 2.1. Kiln head auxiliary heating facilities; 2.1.1. Outlet cut-off valve; 2 .1.2, combustion-supporting fan; 2.1.3, burner; 2.1.4, gas shut-off valve; 2.1.5, gas regulating valve; 2.2, rotary kiln; 2.2.1, wireless temperature measuring thermocouple; 2.3, settling chamber; 2.4, surface cooler / waste heat boiler; 2.5, bag filter; 2.6, main exhaust fan; 2.7, desulfurization; 2.8, finished product of secondary zinc oxide; 2.9, returned secondary zinc oxide; 2.10, kiln slag; 2.11, blower; 2.12, kiln head flame imaging; 2.13, infrared detection facility for outer wall temperature. DETAILED DESCRIPTION

[0041] Exemplary embodiments of the present invention are described in detail below. Although these exemplary embodiments are described in sufficient detail to enable those skilled in the art to implement the present invention, it should be understood that other embodiments may be implemented and various changes may be made to the present invention without departing from the spirit and scope of the present invention. The more detailed description of the embodiments of the present invention below is not intended to limit the scope of the claimed invention, but is merely for illustration and does not limit the description of the features and characteristics of the present invention, in order to propose the best mode for performing the present invention, and is sufficient to enable those skilled in the art to implement the present invention. Therefore, the scope of the present invention is limited only by the appended claims.

[0042] Example 1

[0043] The present embodiment provides a process control method for an automated production line for comprehensive utilization of metallurgical dust and sludge, including a rotary kiln batching control system, a rotary kiln roasting temperature automatic control system, and a rotary kiln high temperature section position control system. Figure 1 As shown, the metallurgical dust and sludge comprehensive utilization production line includes a raw material system 1 and a rotary kiln roasting system 2.

[0044] Rotary kiln batching control system:

[0045] like Figure 1As shown, in the raw material system 1, dry ash 1.1, water-containing ash 1.6 and metallurgical mud 1.10 are stored separately. Metallurgical dust removal dry ash, carbon powder and auxiliary materials are stored in an elevated dry ash bin 1.2. The cone section angle of the dry ash bin 1.2 is between 15° and 25°, and several bin wall vibrators are provided to ensure that the dry ash can fall smoothly. The lower part of the dry ash bin 1.2 is provided with a star-shaped ash discharge valve 1.3 and a fully sealed belt scale 1.4 to achieve quantitative control of the dry ash 1.1. The quantitatively discharged ash is sent to the mixer for mixing through a sealed buried scraper 1.5. During the whole process, the dry ash 1.1 is transported in a closed device to avoid the dry ash 1.1 from being transported backwards. The dust problem in the process is solved, the on-site environment is improved, and quantitative feeding is realized, which greatly reduces the labor intensity of workers; the water-containing ash 1.6 is poured into the receiving trough 1.7 by a dump truck, and then quantitative feeding is realized through a screw feeder 1.8 and a belt scale 1.9, and is sent to a mixer 1.15 for mixing by an buried scraper 1.5; the metallurgical mud 1.10 contains more water, and is sent to the sludge bin 1.11 by a dump truck or a pump, and is quantitatively transported to the mixer 1.15 for mixing by a hydraulic slide 1.12, a double screw feeder 1.13 and a plunger pump 1.14.

[0046] like Figure 2 As shown, the control principle of the rotary kiln batching control system is as follows: according to the raw material conditions to be processed in production, the components and processing amounts of dust removal dry ash, water-containing ash 1.6 and metallurgical mud 1.10 are respectively input into the batching control system on the computer, and the batching control system calculates the amount of carbon powder and auxiliary materials to be added according to the input raw material conditions; the quantitative feeding equipment 1.4, 1.9, 1.14 controls the feeding amount of each raw material according to the calculation results.

[0047] Rotary kiln roasting temperature automatic control system:

[0048] The rotary kiln 2.2 in the rotary kiln roasting system 2 receives the raw materials mixed by the mixer 1.15 in the raw material system 1 at the kiln tail. The volatile metal oxides such as lead and zinc in the mixed materials are reduced to metal vapor by carbon powder and the carbon monoxide generated by the carbon powder at 1050-1250°C in the rotary kiln 2.2. The metal vapor enters the dust collection process in the back-end with the smoke of the rotary kiln 2.2 and is reoxidized to metal oxides and collected. The oxidation settling chamber 2.3 and the surface cooler (waste heat boiler) 2 .4. The smoke collected by the dust collecting equipment such as the bag filter 2.4 is the finished zinc oxide product 2.8 of different grades. Among them, the zinc oxide 2.9 collected in the settling chamber 2.3 is of lower grade and is returned to the rotary kiln 2.2 for re-roasting. The other smoke meets the emission standards after the dust removal 2.3 to 2.5 and desulfurization 2.7 processes. Other non-volatile oxides in the material will form kiln slag 2.10, which will be returned to the smelting production line or other refining processes after water quenching or dry granulation treatment.

[0049] like Figure 3As shown in Figure 2, the heat input of the rotary kiln is divided into the carbon brought in by the raw materials and the heat brought in by the kiln head auxiliary heating system 2.1. When organizing production, it is necessary to ensure that the sum of the heat input of the rotary kiln is 1500-1800 kcal. The heat brought in by the raw materials is calculated by formula-1, and the heat brought in by the kiln head auxiliary heating system is calculated by formula-2.

[0050]

[0051] Q 煤气 =q 煤气 ×L 煤气 Formula-2

[0052] 393.5 is the enthalpy of burning 1g of carbon into CO2, Q C : The heat brought by the carbon in the raw material; Q i : mass fraction of a certain raw material in a unit mixed raw material; C di : Carbon content in a certain raw material; Q 煤气 : The heat generated by the gas consumed by the unit mixture; q 煤气 : Gas calorific value; L 煤气 : The amount of gas consumed per unit mixture.

[0053] The heat output of the rotary kiln mainly includes: the heat absorbed by the reduction of metal oxides Q 反应 ; Heat absorbed by flue gas Q 烟气 ; Heat absorbed by kiln slag Q 窑渣 ; Heat Q absorbed by water temperature rise and vaporization in ingredients 水 ; Heat absorbed by the kiln body and supporting facilities Q 散 ; Heat absorbed by smoke Q 尘 .

[0054] The relationship between the rotary kiln roasting temperature and heat input is as follows:

[0055]

[0056] T 焙烧 : calcination temperature; T0: initial temperature of raw materials; c 窑渣 : Specific heat capacity of slag; m 窑渣 : The weight of slag generated per unit raw material.

[0057] During the production process, the roasting temperature of the rotary kiln will be fed back to the automatic control system of the roasting temperature of the rotary kiln. Among them, the kiln head auxiliary heating system 2.1 directly supplies heat to the rotary kiln, and the speed of regulating the roasting temperature of the rotary kiln is relatively fast; there is a certain lag in controlling the roasting temperature of the rotary kiln by adjusting the carbon amount through the batching system, so this control method is only used when the roasting temperature deviation of the rotary kiln is large. The configuration of the automatic control system of the roasting temperature of the rotary kiln is as follows: the kiln head auxiliary heating system 2.1 includes a burner 2.1.3, a combustion-supporting fan 2.1.2, a combustion-supporting fan outlet shut-off valve 2.1.1, a gas shut-off valve 2.1.4, and a gas regulating valve 2.1.5; a wireless temperature measuring thermocouple 2.2.1 is set in the high-temperature section of the rotary kiln 2.2 body; and a fully sealed belt scale 1.4 is set at the lower part of the carbon powder dry ash bin 1.2 of the raw material system 1. The automatic control process of the roasting temperature of the rotary kiln is as follows: Figure 4 As shown: the roasting zone temperature interval 1 (1130℃~1180℃) is set, the control system calculates the required carbon dosage according to the material conditions, and quantitatively doses the materials through the raw material system 1. The roasting zone temperature T is measured by the wireless temperature measuring thermocouple 2.2.1 set on the rotary kiln 2.2 body i , and fed back to the control system for judgment. At this time, three situations will occur: The first situation is that the temperature T i In the set roasting temperature range 1, the control system maintains the current production state; the second case is the temperature T i If the temperature exceeds temperature interval 1 but is within temperature interval 2 (1100℃~1200℃), the temperature of the roasting zone of the rotary kiln has a small deviation from the set temperature interval. The control system will adjust the heat input by controlling the auxiliary heating facilities at the kiln head to control the roasting temperature within the set temperature interval 1. The third case is temperature T i When the temperature exceeds temperature range 2, the temperature of the roasting zone of the rotary kiln deviates greatly from the set temperature range. The control system will adjust the roasting temperature of the rotary kiln by adjusting the heat input of the kiln head auxiliary heating 2.1 facility and the carbon amount of the batching system.

[0058] Rotary kiln high temperature section position control system:

[0059] According to the temperature changes in each zone in the kiln, it is generally divided into four sections from the kiln tail to the kiln head according to the temperature from high to low, which are the drying section, preheating section, high temperature section, and cooling section. Among them, the high temperature section is the main reaction section where zinc is reduced and precipitated. Production practice shows that the temperature of the high temperature section should be 1100-1200℃, the length of the high temperature section should be 1 / 3-2 / 3 of the total length of the kiln body, and the roasting end position is about 0.5m away from the kiln head retaining ring. In addition to stabilizing the fixed carbon content and blast oxygen supply, appropriately increasing the blast volume and the negative pressure at the kiln tail can extend the length of the high temperature section, increase the flue gas temperature, and increase the product yield. However, if the high temperature section is too long, the load on the dust collection facilities behind will increase, and there is a risk of burning the bags. Figure 5As shown, the high temperature section position control system of the rotary kiln includes: a variable frequency Roots blower for kiln head blast 2.11 of the rotary kiln 2.2, an infrared detection device 2.13 for the outer wall temperature of the rotary kiln for monitoring the kiln skin temperature, a variable frequency main exhaust fan 2.6 for adjusting the main exhaust volume of the rotary kiln and the system negative pressure, and a flame imaging system 2.12 for monitoring the roasting conditions in the rotary kiln.

[0060] like Figure 6 As shown, the principle of the high temperature section position control of the rotary kiln is: the axial temperature distribution of the rotary kiln is continuously measured by the infrared detection facility 2.13 of the temperature of the outer wall of the rotary kiln. If the high temperature section is within a reasonable range, the existing production parameters are maintained; if the high temperature section is not within a reasonable range, the position of the high temperature section is adjusted by adjusting the pressure head and air volume through the variable frequency Roots blower 2.11 at the kiln head and the variable frequency main exhaust fan 2.6 at the kiln tail. When the high temperature section is close to the kiln head, the motor frequency of the variable frequency Roots blower 2.11 at the kiln head is increased to increase the kinetic energy and air volume of the blast, so that the air blown into the system can reach a position farther from the kiln head, and at the same time, the motor frequency of the variable frequency main exhaust fan 2.6 at the kiln tail is increased to increase the exhaust volume and negative pressure, so that the smoke in the high temperature section of the kiln moves faster to the kiln tail, so as to achieve the purpose of moving the high temperature section backward. At the same time, the kiln head flame imaging system 2.11 can be used to assist in judging the roasting condition of the rotary kiln, without the need to go to the site to see the fire.

[0061] Embodiment 2

[0062] In this embodiment, we further elaborate on the actual application of the process control method of the automated production line for comprehensive utilization of metallurgical dust and sludge.

[0063] Raw material storage details

[0064] The elevated dry ash silo not only has a cone angle designed between 15° and 25°, but its silo wall is also made of special wear-resistant material to cope with the friction during long-term storage and unloading. The accuracy of the radar level meter has been strictly calibrated and can accurately feedback the inventory of dry ash in the silo in real time, providing a reliable basis for production scheduling.

[0065] The grid plates of the underground water-containing ash receiving trough are carefully designed to effectively filter out larger particles of impurities and prevent them from entering the subsequent feeding system, and are also easy to clean and maintain. The sludge receiving bin is located below the ground and adopts a sealed design to prevent the spread of sludge odor. It is also equipped with a liquid level monitoring device to ensure that the storage volume of sludge is within a safe range.

[0066] Dosing process optimization

[0067] The discharge speed of the dry ash star-shaped discharge valve can be precisely adjusted according to production requirements. The fully enclosed belt scale uses advanced sensor technology to monitor the flow of dry ash in real time and transmit the data to the control system to achieve accurate quantitative feeding. The operating speed and scraper spacing of the buried scraper are optimized to ensure the stability and uniformity of the dry ash during transportation.

[0068] The spiral blades of the wet material screw feeder are made of special materials and designed to effectively transport the wet ash and prevent blockage. The belt scale works with the screw feeder to accurately control the feeding amount of the wet ash. When conveying wet ash, the buried scraper is more closely connected with other equipment, reducing the leakage and loss of materials.

[0069] The sludge hydraulic slide moves more smoothly, ensuring smooth discharge of sludge from the sludge bin. The screw diameter and pitch of the double screw discharger are optimized to improve the sludge conveying efficiency. The plunger pump quantitative conveyor adopts a high-precision plunger pump, which can accurately control the sludge conveying volume and ensure the accurate ratio with other raw materials.

[0070] Mixing system performance improvement

[0071] The powerful mixer adopts a multi-axis mixing design, and the shape and angle of the mixing blades are optimized to fully mix various raw materials in a short time. The interior of the mixer is also equipped with a special guide plate to enhance the mixing effect and ensure that the carbon and iron in the raw materials are evenly distributed.

[0072] Example 3

[0073] This embodiment will focus on the application of the automated production line for comprehensive utilization of metallurgical dust and sludge under different production conditions.

[0074] 1. Strategies for dealing with changes in raw materials

[0075] Adjustment of ingredients for raw materials with different components

[0076] When the composition of the treated metallurgical dust changes, such as fluctuations in zinc content and iron content, the rotary kiln batching control system can respond quickly. The control system recalculates the amount of carbon powder and auxiliary materials to be added based on the new raw material composition analysis results. The quantitative feeding equipment automatically adjusts the feeding amount based on the new calculation results to ensure that the composition of the mixed material meets the roasting requirements.

[0077] For metallurgical dust and sludge with complex ingredients, the control system can use intelligent optimization algorithms to predict the best batching plan based on historical production data and real-time monitoring data, thereby improving production efficiency and product quality.

[0078] Dealing with changes in raw material humidity

[0079] When the humidity of the raw materials changes, the screw feeder and belt scale of the water-containing ash receiving trough can automatically adjust the feeding speed to adapt to the change in material fluidity caused by the humidity change. At the same time, the hydraulic slide, double screw discharger and plunger pump quantitative conveyor of the sludge receiving bin will also adjust the conveying parameters according to the humidity of the sludge to ensure accurate quantitative conveying of the sludge.

[0080] In order to cope with the impact of raw material humidity changes on rotary kiln roasting, the rotary kiln roasting temperature automatic control system will monitor the temperature changes in the roasting area in real time and adjust the kiln head auxiliary heating facilities and carbon dosage according to temperature feedback. For example, when the raw material humidity increases, the heat input of the kiln head auxiliary heating facilities needs to be increased to compensate for the heat required for water evaporation and ensure that the roasting temperature is stable within the set range.

[0081] 2. Adaptability to changes in production scale

[0082] Expanding production scale

[0083] When the production scale is expanded, the various systems of the metallurgical dust and sludge comprehensive utilization automatic production line need to be upgraded and adjusted accordingly. The storage system of the rotary kiln batching control system needs to increase the storage capacity, and the quantitative feeding system and mixing system need to improve the processing capacity. For example, the number and capacity of the elevated dry ash silo can be increased, the layout and parameters of the quantitative feeding equipment can be optimized, and the mixing efficiency of the mixer can be improved.

[0084] The automatic control system for the roasting temperature of the rotary kiln needs to readjust the heat input and temperature control parameters according to the expanded production scale. The burners, combustion-supporting fans and other equipment of the kiln head auxiliary heating system need to be upgraded as needed to meet the greater heat demand. At the same time, the number and distribution of wireless temperature measuring thermocouples also need to be optimized to ensure accurate monitoring of the temperature in the roasting area.

[0085] The variable frequency Roots blower and variable frequency main exhaust fan of the rotary kiln high temperature section position control system need to improve power and performance to adapt to the expanded production scale. The kiln head flame imaging system and the infrared detection facilities of the rotary kiln outer wall temperature also need to be upgraded to provide more accurate monitoring data.

[0086] Reduce production scale

[0087] When the production scale is reduced, each system can be adjusted and optimized accordingly to reduce energy consumption and operating costs. For example, the rotary kiln batching control system can reduce the number of quantitative feeding equipment in operation, optimize the working parameters of the mixing system, and improve the utilization rate of raw materials.

[0088] The automatic control system of the rotary kiln roasting temperature can adjust the heat input and carbon content of the kiln head auxiliary heating facilities according to the reduced production scale to reduce energy consumption.

[0089] The rotary kiln high temperature section position control system can adjust the operating parameters of the variable frequency Roots blower and the variable frequency main exhaust fan to reduce the blowing and exhaust volumes to adapt to the reduced production scale. The kiln head flame imaging system and the infrared detection facilities for the outer wall temperature of the rotary kiln can continue to operate to ensure the safety and stability of the production process.

[0090] The examples described in the present invention are merely descriptions of the preferred implementation modes of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made to the technical solutions of the present invention by engineers and technicians in this field should all fall within the protection scope of the present invention.

Claims

1. A rotary kiln treatment system for zinc-containing dust and sludge, characterized in that: The invention comprises a batching system (1) and a roasting system (2); the batching system is used for mixing raw materials and then conveying them to a rotary kiln; the roasting system (2) comprises a roasting temperature automatic control system and a high temperature section position control system, the roasting temperature automatic control system is used for adjusting the roasting temperature, and the high temperature section position control system is used for adjusting the position of the roasting section.

2. A rotary kiln treatment system for zinc-containing dust and sludge according to claim 1, characterized in that: The batching system (1) comprises a storage unit, a quantitative feeding unit and a mixing unit which are connected in sequence; the storage unit comprises a dry ash bin (1.2) for storing dry ash (1.1), a receiving trough (1.7) for storing water-containing ash (1.6) and a sludge bin (1.11) for storing metallurgical mud (1.10); the quantitative feeding unit is arranged at the discharge port of the storage unit to control the quantitative transportation of the material; the mixing unit is used to mix the material evenly.

3. A rotary kiln treatment system for zinc-containing dust and sludge according to claim 2, characterized in that: The quantitative feeding system comprises an ash discharge valve (1.3) and a fully sealed belt scale (1.4) installed at the outlet of a dry ash bin (1.2), a screw feeder (1.8) and a belt scale (1.9) installed at the outlet of a receiving trough (1.7), a hydraulic slide (1.12), a double screw feeder (1.13) and a plunger pump (1.14) installed at the outlet of a sludge bin (1.11), and an embedded scraper conveyor (1.5) installed at the outlet of the fully sealed belt scale (1.4) and the belt scale (1.9); the mixing unit comprises a mixer (1.15) installed at the outlet of the embedded scraper conveyor (1.5) and the plunger pump (1.14).

4. A rotary kiln treatment system for zinc-containing dust and sludge according to claim 1, characterized in that: The roasting temperature automatic control system comprises a kiln head auxiliary heating facility (2.1); the kiln head auxiliary heating facility (2.1) comprises a burner (2.1.3) connected to an air supply pipeline and a combustion-supporting fan (2.1.2) connected to the burner (2.1.3); an outlet shut-off valve (2.1.1) is installed on the pipeline between the combustion-supporting fan (2.1.2) and the burner (2.1.3); and a gas shut-off valve (2.1.4) and a gas regulating valve (2.1.5) are installed on the air supply pipeline.

5. A rotary kiln treatment system for zinc-containing dust and sludge according to claim 4, characterized in that: The roasting temperature automatic control system also includes a roasting section temperature measuring facility, and the roasting section temperature measuring facility is a wireless temperature measuring thermocouple (2.2.1) for measuring the roasting temperature.

6. A rotary kiln treatment system for zinc-containing dust and sludge according to claim 1, characterized in that: The high temperature section position control system comprises a blower (2.11) for blowing air at the kiln head of the rotary kiln, an infrared detection facility (2.13) for monitoring the temperature of the kiln skin, a main exhaust fan (2.6) for adjusting the main exhaust volume of the rotary kiln and the negative pressure of the system, and a flame imaging system (2.12) for monitoring the roasting conditions in the rotary kiln.

7. A rotary kiln treatment method for zinc-containing dust sludge, characterized in that: The total heat input of the rotary kiln is controlled to be 1500-1800 kcal; the heat input of the rotary kiln includes the carbon brought into the raw materials and the heat brought into the kiln head auxiliary heating facilities (2.1), which is calculated by the following formula: Q 煤气 =q 煤气 ×L 煤气 ; Among them, 393.5 is the enthalpy of burning 1g of carbon element into CO2; Q C The heat brought by the carbon in the raw material; Q i is the mass fraction of a certain raw material in the unit mixture; C di is the carbon content in a certain raw material; Q 煤气 The heat generated by the gas consumed by the unit mixture; q 煤气 is the calorific value of gas; L 煤气 The amount of gas consumed per unit mixture.

8. The rotary kiln treatment method for zinc-containing dust and sludge according to claim 7, characterized in that: The roasting temperature of the rotary kiln is controlled by the following formula: Among them, T 焙烧 is the roasting temperature; T0 is the initial temperature of the mixture; c 窑渣 is the specific heat capacity of slag; m 窑渣 The weight of slag generated per unit mixture.

9. The rotary kiln treatment method for zinc-containing dust sludge according to claim 8, characterized in that: When the roasting temperature is between 1130°C and 1180°C, the control system maintains the existing production state; when the roasting temperature exceeds 1130°C to 1180°C and is between 1100°C and 1200°C, the heat input is adjusted through the kiln head auxiliary heating facility (2.1) to adjust the roasting temperature to between 1130°C and 1180°C; when the roasting temperature exceeds 1100°C to 1200°C, the roasting temperature is adjusted by the kiln head auxiliary heating facility (2.1) and the batching of the batching system (2.1) at the same time.

10. The rotary kiln treatment method for zinc-containing dust and sludge according to claim 9, characterized in that: The rotary kiln is divided into a drying section, a preheating section, a high-temperature section and a cooling section from the kiln tail to the kiln head. The high-temperature section is the main reaction section where zinc is reduced and precipitated. The temperature of the high-temperature section is set to 1100°C to 1200°C, the length of the high-temperature section is 1 / 3 to 2 / 3 of the total length of the kiln body, and the roasting end point is 0.45m to 0.55m away from the kiln head retaining ring.

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