Process method for inhibiting ring formation of zinc removal rotary kiln

Abstract

The invention relates to a process method for inhibiting ring formation of a zinc removal rotary kiln. The process method comprises the following steps: S1, optimizing an ingredient structure: strictly controlling the moisture of a material entering a furnace to be 20-25%, controlling the carbon content to be 1500-1700 kilocalories and controlling the particle size to be 3-8 mm; s2, optimizing a roasting process: sequentially dividing the rotary kiln into a drying section, a preheating section, a high-temperature section and a cooling section from the kiln head to the kiln tail by adopting a segmented roasting technology; wherein the temperature of the high-temperature section is controlled to be 1150-1250 DEG C, the whole calcination time is controlled to be 90-110 min, and the furnace charge filling rate is controlled to be 14-16%; s3, auxiliary equipment is additionally arranged, specifically, a barrel temperature scanner and a pressure detection device are installed on the rotary kiln, the temperature and pressure in the kiln are monitored in real time, and technological parameters are adjusted according to detection data; and S4, initial ring formation removal. By means of optimizing the batching structure, improving the roasting process, additionally arranging auxiliary equipment and the like, stable and continuous operation of the rotary kiln can be achieved, and the operation rate of the rotary kiln is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metallurgy, and particularly relates to a process method for inhibiting ring formation in a dezincification rotary kiln. Background Art

[0002] In the production line of treating zinc-containing dust and sludge by a rotary kiln, powdered materials are fed into the kiln, and after mixing zinc-containing dust and sludge with different components, they are directly sent into the rotary kiln for roasting. However, such a process itself has disadvantages, that is, serious ring formation in the furnace kiln.

[0003] Currently, Application No. 201210193050.7, titled "A Method for Preventing the Formation of Sintering Rings in a Rotary Kiln" provides a solution. This patent makes the position of the firing zone change regularly by reasonably controlling the flow rates of the combustion-supporting air and the induced draft, so that the long and thick kiln skin and the initial ring formation fall off and a sintering ring cannot be formed. It includes the control of the combustion-supporting air flow rate, the control of the induced draft flow rate, and the control of the gas flow rate.

[0004] However, the above-mentioned prior art does not cover the roasting raw materials, combustion process, etc. of the rotary kiln, and there is no improvement in optimizing the batching structure, controlling the roasting temperature, and installing auxiliary devices for inhibiting ring formation, and the effect of inhibiting ring formation in the rotary kiln is limited. Summary of the Invention

[0005] Aiming at the above problems, the purpose of the present invention is to provide a process method for inhibiting ring formation in a dezincification rotary kiln, and by means of optimizing the batching structure, improving the roasting process, and adding auxiliary equipment, etc., to achieve the stable and continuous operation of the rotary kiln and improve the operation rate of the rotary kiln.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A process method for inhibiting ring formation in a dezincification rotary kiln proposed by the present invention specifically includes the following steps:

[0008] S1. Optimization of the batching structure:

[0009] The moisture content of the materials fed into the furnace is strictly controlled at 20 - 25%, the carbon content is controlled at 1500 - 1700 kcal, and the particle size is controlled at 3 - 8 mm;

[0010] S2. Optimization of the roasting process:

[0011] Adopt a segmented roasting technology, and divide the rotary kiln from the kiln head to the kiln tail into a drying section, a preheating section, a high-temperature section, and a cooling section in sequence; among them, the temperature of the high-temperature section is controlled at 1150 - 1250 °C, the entire calcination time is controlled at 90 - 110 min, and the furnace charge filling rate is controlled at 14 - 16%;

[0012] S3. Add auxiliary equipment:

[0013] Install a cylinder temperature scanner and a pressure detection device on the rotary kiln to monitor the temperature and pressure inside the kiln in real time, and adjust the process parameters according to the detected data;

[0014] S4. Initial ring removal.

[0015] Furthermore, the step S4 includes: when an initial ring is found, promptly use the ring burning method to remove the ring; the specific removal method is:

[0016] Adjust the position of the burners inside the rotary kiln or increase the amount of injected fuel so that the high-temperature zone can repeatedly calcine the ring zone, melting the adhered ring substances;

[0017] For the rings that are difficult to remove at the kiln head, use the hammer impact method to impact the ring part to remove the ring.

[0018] Furthermore, the hammer head of the hammer is a steel drill rod with a diameter of Φ60×5M.

[0019] The present invention has the following beneficial effects compared with the prior art:

[0020] 1. By means of optimizing the batching structure, optimizing the roasting process, adding auxiliary facilities, and promptly removing the initial rings, etc., the present invention can significantly reduce the deposition of ring substances inside the rotary kiln, extend the continuous operation time of the equipment, and thus improve the production operation rate.

[0021] 2. By reducing the equipment downtime and improving the production operation rate, the present invention effectively reduces the production cost per unit product, and thus can effectively improve the economic benefits. Description of the Drawings

[0022] Figure 1 It is a schematic diagram of the effect of mechanically removing rings from the rotary kiln.

[0023] Among them, the reference numerals: 1 - material inlet; 2 - kiln head ring; 3 - drill rod; 4 - ring cleaning machine. Detailed Embodiments

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] A process method for suppressing ring formation in a dezincification rotary kiln proposed by the present invention specifically includes the following steps:

[0026] S1. Optimization of the batching structure:

[0027] The particle size, composition and moisture content of dust produced in different production processes of steel enterprises are very different. Particles with a particle size of less than 0.25 mm account for about 33% of blast furnace dry dust and electric furnace dust. The carbon content of blast furnace dust is relatively high, even reaching 30-40%, while electric furnace dust basically contains no carbon.

[0028] Therefore, the batching structure of rotary kiln production is very important. It is necessary to fully mix the materials of different varieties and compositions entering the kiln. The mixed materials must be tested and analyzed in each shift to control the particle size, moisture, grade (Zn and Fe), and carbon content of the raw materials entering the kiln.

[0029] In the present invention, the moisture content of the materials entering the furnace is strictly controlled at 20-25%, the carbon content is controlled at 1500-1700 kcal, the particle size is controlled at 3-8 mm, and the materials are balled as much as possible to reduce the amount of fine powder entering the kiln;

[0030] After testing the composition and moisture of different raw materials, strong mixing equipment is used to carry out strong mixing to achieve various indicators of the mixed materials entering the kiln.

[0031] S2. Optimization of roasting process:

[0032] The rotary kiln is divided into drying section, preheating section, high temperature section and cooling section from the kiln head to the kiln tail by adopting the segmented roasting technology; the temperature of the high temperature section is controlled at 1150-1250℃, the whole calcination time is controlled at 90-110min, and the charge filling rate is controlled at 14-16%; to ensure the full reduction and volatilization of zinc, and to reduce the residence time of the material in the kiln, and to prevent the material from sticking due to too long residence time.

[0033] At the same time, a secondary air supply fan is added to the rotary kiln to transport combustion-supporting air into the kiln, thereby increasing the combustion rate of the combustion gas, extending the length of the high-temperature zone, forming a reasonable temperature distribution, preventing local heat concentration, avoiding local high temperatures and thus reducing the occurrence of ringing.

[0034] S3. Add auxiliary equipment:

[0035] A cylinder temperature scanner and pressure detection device are installed in the rotary kiln to monitor the temperature and pressure inside the kiln in real time, and the process parameters are adjusted according to the detection data to ensure the stability and efficiency of the production process.

[0036] S4. Initial ring removal.

[0037] When the initial ring is found, the ring burning method should be used to remove the ring in time; the specific removal method is as follows:

[0038] Adjust the position of the burner in the rotary kiln or increase the amount of fuel injection so that the high-temperature zone can repeatedly calcine the ring zone and melt the adhered ring material;

[0039] For the stubborn buildups at the kiln head, the hammer impact method is used for removal (as Figure 1 shown). The hammer head is replaced with a self-made steel drill rod of Φ60×5M to impact the buildup area until the buildup is removed, avoiding the previous kiln shutdown for disposal.

[0040] The present invention will be further described below through specific examples:

[0041] Taking the zinc-containing metallurgical dust and sludge actually produced by a certain iron and steel enterprise as an example, the batching optimization, roasting optimization, addition of auxiliary equipment and initial buildup treatment are carried out according to the technical solution described in the present invention; the specific implementation process is as follows:

[0042] Batching structure optimization: Mix the zinc-containing metallurgical dust and sludge, electric furnace ash and other zinc-containing materials evenly in a certain proportion, ensure that the moisture in the mixture is strictly controlled within 20-25%, the carbon content is controlled at 1600 kcal, and the particle size is controlled within 3-8 mm and made into balls as much as possible.

[0043] Roasting process optimization: Load the mixture into a rotary kiln with a flue gas recovery system and carry out staged roasting. The temperature in the high-temperature section is controlled within 1250 °C, and the combustion rate of the combustion gas is increased through the secondary air blower to extend the length of the high-temperature zone.

[0044] Addition of auxiliary equipment: The state inside the kiln is monitored in real time through a temperature scanner and a pressure detection device, and the process parameters are adjusted according to the detection data to ensure the stability and high efficiency of the production process.

[0045] Treatment of initial buildup: The burning method and the hammer impact method are used to effectively remove the initial buildup, avoiding the previous kiln shutdown for disposal.

[0046] The present invention controls the physical and chemical conditions for the formation of buildups through multiple dimensions, thereby reducing or eliminating the buildup phenomenon. The specific internal logic and action principle are as follows:

[0047] I. Optimization of batching structure

[0048] By adjusting the raw material composition, the generation of low-melting-point substances is reduced, and the liquid phase amount and adhesiveness are lowered.

[0049] Large fluctuations in the raw material composition will result in great differences in its composition, moisture, and fine powder particle size, which will further lead to instability in the thermal regime inside the kiln, causing overburning or underburning of the material from time to time and increasing the probability of liquid phase adhesion. By stabilizing the raw material ratio, the occurrence of local high-temperature zones and the melting and bonding of a large amount of fine powder due to uneven raw materials can be avoided.

[0050] II. Optimization of roasting process

[0051] By adjusting the thermal regime, the temperature distribution inside the kiln and the liquid phase generation conditions are controlled to avoid local high-temperature or low-temperature fluctuations.

[0052] An overly long flame or too high a temperature (e.g., >1250 °C) can cause Fe3O4 to react with SiO2 to form a liquid phase, which adheres to the kiln wall. Optimizing the combustion parameters can shorten the flame, disperse the high-temperature zone, keep the material evenly heated, reduce the formation of the liquid phase, and avoid the liquid phase solidifying and adhering due to sudden temperature changes to form a ring.

[0053] III. Adding auxiliary equipment

[0054] Add a temperature scanner and a pressure detection device to monitor the temperature and pressure distribution in the kiln in real time, accurately control the process parameters, and avoid the critical conditions for ring formation.

[0055] The temperature scanner can capture abnormal temperature areas in the kiln in real time. If it detects that the temperature in a certain section exceeds the liquid-phase formation threshold, the feeding amount or air volume can be adjusted in time to avoid liquid-phase adhesion caused by local high temperature.

[0056] Through pressure detection, abnormal negative pressure in the kiln can be detected in advance, and thus signs of ring formation can be detected early, so as to adjust the induced draft in time to improve the air flow distribution and destroy the ring formation environment.

[0057] IV. Handling initial rings

[0058] Handling initial rings is a physical intervention in early rings to prevent them from thickening and expanding.

[0059] By using the ring burning method and the hammer impact method, initial rings can be effectively removed, preventing the need to stop the kiln for disposal due to thickening and expansion of the rings, which would cause the rotary kiln to shut down and increase the disposal cost.

[0060] The above suppression measures act together on two key conditions for ring formation:

[0061] 1. Liquid-phase quantity control: By optimizing the batching and temperature, reduce the formation of low-melting-point compounds and lower the proportion of adhesive liquid phase.

[0062] 2. Timeliness of suppressing and removing initial rings: Through monitoring devices and process optimization, maintain the stability of the thermal regime in the kiln, reduce temperature fluctuations and local high temperatures, and thus inhibit the ring formation cycle; at the same time, through physical removal intervention, timely block the accumulation of rings.

[0063] Through the above multi-dimensional synergistic effects, the formation of rings in the rotary kiln can be effectively suppressed, and the equipment operation rate and production efficiency can be improved.

[0064] Matters not detailed in this invention are all well-known technologies.

[0065] The embodiments described above are only descriptions of the preferred embodiments of the present invention and do not limit the scope of the present invention. Without departing from the spirit of the present invention's design, various modifications and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A process for inhibiting ring formation in a dezincification rotary kiln, characterized in that: The method comprises the following steps: S1. Optimization of ingredient structure: The moisture content of the materials entering the furnace is strictly controlled at 20-25%, the carbon content is controlled at 1500-1700 kcal, and the particle size is controlled at 3-8 mm; S2. Optimization of roasting process: The rotary kiln is divided into drying section, preheating section, high temperature section and cooling section from the kiln head to the kiln tail by adopting the segmented roasting technology; the temperature of the high temperature section is controlled at 1150-1250℃, the whole calcination time is controlled at 90-110min, and the charge filling rate is controlled at 14-16%; S3. Add auxiliary equipment: Install a cylinder temperature scanner and pressure detection device in the rotary kiln to monitor the temperature and pressure in the kiln in real time and adjust the process parameters according to the detection data; S4. Initial ring removal.

2. The process for inhibiting ring formation in a dezincification rotary kiln according to claim 1, characterized in that: The step S4 includes: when the initial ring is found, the ring is promptly removed by burning the ring; the specific removal method is: Adjust the position of the burner in the rotary kiln or increase the amount of fuel injection so that the high-temperature zone can repeatedly calcine the ring zone and melt the adhered ring material; For the rings that are difficult to remove at the kiln head, the cannon hammer impact method is used to impact the ring-forming area to remove the rings.

3. A process for inhibiting ring formation in a dezincification rotary kiln according to claim 2, characterized in that: The blaster head of the blaster hammer is a steel chisel of Φ60×5M.

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