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CN-121976037-A - Process for producing blast furnace iron pellets by comprehensively utilizing iron-containing solid wastes

CN121976037ACN 121976037 ACN121976037 ACN 121976037ACN-121976037-A

Abstract

The invention discloses a process for producing blast furnace iron pellets by comprehensively utilizing iron-containing solid wastes, which aims at comprehensively and accurately analyzing various solid wastes and other iron-containing solid wastes in the steel industry, accurately proportions flux and fuel based on the solid wastes, adopts a variable temperature-control roasting technology, accurately regulates and controls the temperature and the rotating speed of a rotary kiln, ensures that materials react fully and stay time is proper, monitors and accurately regulates and controls the atmosphere in the rotary kiln in real time, creates excellent conditions for iron oxide reduction and other reactions, and ensures the efficient utilization of energy and the environment-friendly standard of advanced desulfurization, denitration and dedusting integrated tail gas treatment equipment, and a dust collecting device, storage management and a cold-pressing ball process of the dust collecting device ensure reasonable application of the dust collecting device in the process.

Inventors

  • WANG ZIMING
  • LIU YINGPING
  • WANG ZHISU

Assignees

  • 无锡中科城投环境工程有限公司

Dates

Publication Date
20260505
Application Date
20260209

Claims (7)

  1. 1. A process for producing blast furnace iron pellets by comprehensively utilizing iron-containing solid wastes is characterized by comprising the following steps: The storage bin is used for storing different solid wastes; The strong mixer is arranged at the output end of the storage bin and used for mixing the collected solid wastes; the rotary kiln is arranged at the output end of the strong mixer and is used for realizing rotary calcination of materials; The central control system is connected with the rotary kiln through signals and is used for automatically adjusting the combustion air quantity to ensure that the temperature is always kept within the range of +/-20 ℃ of the target temperature; The cold extraction water tank is connected with the output end of the rotary kiln, and the rapid cooling of the materials is realized through water quenching; The dust collection cover is arranged at each dust raising point, and the output end of the dust collection cover is connected with a bag-type dust collector for high-efficiency filtration; the waste heat recovery device is connected with the rotary kiln and is used for realizing effective recovery and utilization of waste heat; the desulfurization, denitrification and dedusting integrated treatment equipment is used for removing sulfur dioxide, nitrogen oxides and dust pollutants in tail gas.
  2. 2. The process for producing blast furnace iron pellets by comprehensively utilizing iron-containing solid wastes according to claim 1, wherein the rotary kiln is obliquely installed, the inclination is 5 degrees, and the rotating speed is set to be 1-3 revolutions per minute.
  3. 3. The process for producing blast furnace iron pellets by comprehensively utilizing iron-containing solid wastes according to claim 1, wherein the input end of the rotary kiln is provided with a quantitative feeding device and a blast device, wherein the quantitative feeding device is used for injecting the solid wastes into the rotary kiln, and the blast device is used for spraying air or oxygen into the kiln.
  4. 4. The process for producing blast furnace iron pellets by comprehensively utilizing iron-containing solid wastes according to claim 1, wherein the feeding end, the middle part and the discharging end of the rotary kiln are provided with high-precision temperature sensors, the temperature change in the kiln is monitored in real time, data are fed back to a central control system, and a plurality of gas analyzers are arranged in the rotary kiln to monitor the atmosphere components in the kiln in real time.
  5. 5. The process for producing blast furnace iron pellets by comprehensively utilizing iron-containing solid wastes according to claim 1, which is characterized by comprising the following steps: A1, collecting raw materials, namely widely collecting solid wastes generated in each link of steel production, respectively conveying the collected solid wastes to corresponding storage bins for temporary storage, preventing different types of solid wastes from being mixed with each other, proportionally taking out a proper amount of solid waste samples from each storage bin, conveying the solid waste samples to a laboratory for comprehensive component analysis, and determining the accurate content of the content of each element in the solid wastes; a2, raw material pretreatment, namely precisely adding a flux and fuel into a batching system according to a component analysis result, and conveying the mixed material into a strong mixer to fully stir and mix after the flux and the fuel are added; A3, roasting in a rotary kiln, namely uniformly and stably feeding the uniformly mixed materials into the rotary kiln through a quantitative feeding device, and carrying out rotary roasting, wherein in the roasting process, the reduction of iron elements and the volatilization of part of metal elements are ensured and the enrichment of the iron elements in a multi-pipe cooler and dust collecting equipment are ensured through the control of variable temperature; A4, cooling, namely discharging the roasted material from the output end, directly entering a cold extraction water tank, and cooling the material rapidly by adopting a water quenching cooling mode, and cooling the material to below 100 ℃ to obtain the acidic blast furnace iron pellets; A5, cold-pressing the balls, namely mixing secondary solid waste (dust removal ash) generated by recycling the flue gas of the rotary kiln with converter dust mud in proportion, adding a binder, and preparing the cold-pressing metal balls into alkaline blast furnace iron balls through ball pressing equipment; A6, environmental protection treatment, namely collecting dust-containing gas through a dust hood and then sending the dust-containing gas into a bag-type dust remover to efficiently filter high-temperature tail gas generated by a rotary kiln, so as to realize effective recycling of waste heat, and enabling the tail gas after waste heat recycling to enter desulfurization, denitrification and dedusting integrated treatment equipment, wherein sulfur dioxide, nitrogen oxides and dust pollutants in the tail gas are removed through a series of chemical reaction and physical filtration processes, and the tail gas is discharged through a chimney at high altitude.
  6. 6. The process for producing blast furnace iron pellets by comprehensively utilizing iron-containing solid wastes according to claim 5, wherein the solid wastes collected by the raw materials comprise iron-containing solid wastes such as blast furnace bag dust, converter iron-containing dust and dust sludge, electric furnace dust and the like.
  7. 7. The process for producing blast furnace iron pellets by comprehensively utilizing iron-containing solid wastes according to claim 5, wherein the mixing time in the pretreatment of the raw materials is 30 minutes to ensure uniform distribution of various components.

Description

Process for producing blast furnace iron pellets by comprehensively utilizing iron-containing solid wastes Technical Field The invention relates to the technical field of solid waste treatment and comprehensive utilization of resources in the steel industry, in particular to a process for producing blast furnace iron pellets by comprehensively utilizing iron-containing solid waste. Background In each link of steel production, a large amount of solid waste such as blast furnace slag in the iron making process, converter slag and electric furnace slag in the steel making process, various iron-containing dust and dust removing mud and the like can be generated. The mass production of these solid wastes brings many troubles to iron and steel enterprises. In the traditional treatment mode, a considerable part of comprehensive utilization ways of solid wastes are cement factories and related building material industries. These industries are unable to take full advantage of their greatest value. For example, the iron metal element in the solid waste can be reduced or extracted by roasting and reused as blast furnace ironmaking raw material in smelting. Some iron and steel enterprises also attempt to return these solid wastes directly to the sintering process. However, since the solid waste components are complicated and various, the differences of chemical components, particle size distribution, etc. of each batch of solid waste are large, which makes it difficult to stably control the sintering process. For example, the blast furnace slag contains various trace elements, and fluctuation of the content of the trace elements affects the mineral composition and physical properties of the sinter, so that the quality of the sinter is unstable. After the unstable sinter enters the blast furnace, the smooth running of the blast furnace can be affected, the iron-making efficiency is reduced, the coke ratio is increased, and the production cost is further increased. Still other enterprises employ relatively complex pretreatment processes to treat solid waste in an attempt to improve its performance into subsequent processes. However, these processes tend to be capital intensive and costly to operate. For example, rotary hearth furnaces are expensive to purchase, and consume energy in daily operation and are expensive to maintain. Moreover, these complex processes have high requirements on the technical level of the operators, increasing the manpower costs and the operating risks. In summary, the existing solid waste treatment mode in the steel industry has a series of problems of low resource utilization rate, unstable product quality, high treatment cost and the like, and an efficient, environment-friendly and economical comprehensive utilization process is urgently needed to realize the recycling and harmless treatment of the solid waste in the steel industry and simultaneously provide high-quality raw materials for blast furnace ironmaking. Therefore, the invention provides a process for producing blast furnace iron pellets by comprehensively utilizing iron-containing solid wastes. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a process for producing blast furnace iron pellets by comprehensively utilizing iron-containing solid wastes, which aims to solve the problems. The invention aims at realizing the technical scheme that the process for producing blast furnace iron pellets by comprehensively utilizing iron-containing solid wastes comprises the following steps: The storage bin is used for storing different solid wastes; The strong mixer is arranged at the output end of the storage bin and used for mixing the collected solid wastes; the rotary kiln is arranged at the output end of the strong mixer and is used for realizing rotary calcination of materials; The central control system is connected with the rotary kiln through signals and is used for automatically adjusting the combustion air quantity to ensure that the temperature is always kept within the range of +/-20 ℃ of the target temperature; The cold extraction water tank is connected with the output end of the rotary kiln, and the rapid cooling of the materials is realized through water quenching; The dust collection cover is arranged at each dust raising point, and the output end of the dust collection cover is connected with a bag-type dust collector for high-efficiency filtration; the waste heat recovery device is connected with the rotary kiln and is used for realizing effective recovery and utilization of waste heat; the desulfurization, denitrification and dedusting integrated treatment equipment is used for removing sulfur dioxide, nitrogen oxides and dust pollutants in tail gas. Preferably, the rotary kiln is installed in an inclined mode, the inclination is 5 degrees, and the rotating speed is set to be 1-3 revolutions per minute. Preferably, the input end of the rotary kiln is provided with a quantitative feed