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CN-121971973-A - Large-scale synergistic solidification of low-purity CO from red mud2Resource utilization system and method of (a)

CN121971973ACN 121971973 ACN121971973 ACN 121971973ACN-121971973-A

Abstract

The invention relates to the technical field of the cross of industrial solid waste resource utilization and carbon emission reduction technology, in particular to a resource utilization system and method for CO-solidifying low-purity CO 2 in a large-scale manner by red mud, wherein the resource utilization system comprises a red mud pretreatment unit, a gas-liquid reaction unit, a product separation and modification unit, a resource recovery unit and an intelligent regulation and control unit. According to the invention, through the integrated unit design, the full-flow efficient synergy of red mud treatment and CO 2 solidification is realized, the red mud pretreatment unit adopts closed conveying and accurate on-line monitoring, the uniformity and stability of raw material slurry are ensured, the system can directly treat CO 2 mixed gas (purity 25% -35%) from industrial kiln sources and the like, expensive purification pretreatment is not needed, trace SO 2 、NO X and other components can promote the dissolution of alkaline substances in red mud, a synergistic enhancement effect of treating waste with waste is formed, and the reduction of the comprehensive cost of carbon capture and solidification is facilitated.

Inventors

  • LI XIAOQIANG
  • Zhang Jinken
  • SONG JING
  • MA WENZHI
  • ZHANG KAIHUA

Assignees

  • 广西隆安和泰新材料有限公司

Dates

Publication Date
20260505
Application Date
20260126

Claims (10)

  1. 1. The utility model provides a red mud scale is coordinated solidification low purity CO 2 's resource utilization system which characterized in that includes: The red mud pretreatment unit is used for mixing the red mud with water to prepare pumpable uniform slurry; the gas-liquid reaction unit is communicated with the red mud pretreatment unit and is used for carrying out countercurrent carbonation reaction on the red mud slurry and the gas containing carbon dioxide; The product separation and modification unit is communicated with the gas-liquid reaction unit and is used for dehydrating and separating the reacted solid-liquid mixture and crushing and modifying the solid product; The resource recovery unit is respectively communicated with the liquid outlet and the solid outlet of the product separation and modification unit and is used for recovering sodium carbonate products from the liquid and processing the modified solid products into building materials or soil amendments; And the intelligent regulation and control unit is in signal connection with the units and is used for intensively monitoring and controlling the operation parameters of the whole system.
  2. 2. The recycling system for the red mud scale synergistic curing low-purity CO 2 according to claim 1, wherein the gas-liquid reaction unit comprises a plurality of efficient gas-liquid reaction towers which are arranged in parallel, a pulse gas distribution device positioned at the bottom and a countercurrent contact spray system positioned at the top are arranged in the reaction towers, the diameter of a gas hole of the pulse gas distribution device is 0.5-1mm, the gas distribution uniformity error is less than or equal to 5%, and the spray coverage area of the countercurrent contact spray system is more than or equal to 95% of the inner cross section area of the towers.
  3. 3. The system for recycling CO-solidifying low-purity CO 2 with large scale of red mud according to claim 2, further comprising a CO 2 pressurizing device for pressurizing the carbon dioxide-containing gas with purity of 25% -35% to 0.3-0.5MPa and then delivering the gas to the pulse gas distribution device.
  4. 4. The recycling system of the red mud scale synergistic solidification low-purity CO 2 according to claim 1, wherein the product separation and modification unit comprises a plurality of filter presses arranged in parallel and a modifier adding system, the modifier adding system is used for adding a modifier accounting for 5-15% of the mass of the solid product into the dehydrated solid product, the modifier is a compound system of fly ash and gypsum, and the compound proportion is 3:1.
  5. 5. The system for recycling CO-cured low-purity CO 2 in large scale with red mud according to claim 1, wherein the resource recovery unit comprises a wastewater recycling treatment system, the wastewater recycling treatment system adopts a precipitation-filtration-sodium carbonate recovery process to treat wastewater generated by dehydration, and the treated recycled water is returned to the red mud pretreatment unit for pulping.
  6. 6. The recycling system for the CO-cured low-purity CO 2 based on the red mud scale according to claim 1, wherein the intelligent regulation and control unit adopts a distributed control system and is integrated with an environment-friendly on-line monitoring module for monitoring and controlling the emission concentration of dust and SO 2 、NO X in real time.
  7. 7. A method for recycling red mud based on the system of any one of claims 1 to 6, comprising the steps of: step 1, preparing slurry, namely mixing red mud with water, and stirring to prepare uniform slurry; step 2, carbonation reaction, namely introducing the slurry into a gas-liquid reaction unit, and introducing carbon dioxide-containing gas from the bottom of the reaction unit, so that the slurry and the gas are in countercurrent contact for carbonation reaction; Step 3, dehydration separation, namely, dehydrating and separating the solid-liquid mixture after the reaction to obtain a solid filter cake and wastewater; Step 4, recycling treatment, namely crushing and modifying the solid filter cake to obtain a building material or a soil conditioner; and 5, recovering sodium carbonate, and recycling the wastewater to the step 1 after concentrating, crystallizing and recovering sodium carbonate.
  8. 8. The method for recycling red mud according to claim 7, wherein in the step1, the red mud is bayer process red mud, the pH value of the red mud is 10.29-11.83, and the red mud is mixed with water according to the mass ratio of 1:1.2-1:1.5 to prepare slurry with the water content of 60% -70%.
  9. 9. The method for recycling red mud according to claim 7, wherein in the step 2, the carbon dioxide-containing gas is low-purity gas from industrial sources of boilers, cements and lime kilns, the volume concentration of the carbon dioxide is 25% -35%, the gas pressure is 0.3-0.5MPa, the gas flow rate is 0.8-1.2m/s, the spraying strength of the slurry is 2-3m 3/(h.m2), the reaction temperature is 15-40 ℃, and the reaction time is 30-60 minutes.
  10. 10. The method for recycling red mud according to claim 7, wherein in the step 4, when the solid filter cake is modified, the added modifier is a mixture of fly ash and gypsum according to a ratio of 3:1, the added amount is 5% -15% of the mass of the solid filter cake, the modification comprises a microwave auxiliary process, the microwave power is 300-500W, and the treatment time is 5-10 minutes.

Description

System and method for recycling red mud scale synergistic solidification low-purity CO 2 Technical Field The invention relates to the technical field of the cross of industrial solid waste resource utilization and carbon emission reduction technology, in particular to a resource utilization system and method for CO-solidifying low-purity CO 2 in a large-scale manner by red mud. Background The industrial emission reduction and carbon reduction are of great importance, the alumina industry generates a large amount of red mud every year, the annual emission exceeds 1.5 hundred million tons, the accumulated stockpiling amount in China exceeds 6 hundred million tons, the red mud is strong in alkalinity and high in water content, soil alkalization and groundwater pollution are easy to cause after long-term stockpiling, the pollution becomes a prominent difficult problem of sustainable development of the aluminum industry, the boiler, cement and lime firing industry is also a large household with carbon emission, CO 2 is about 12 hundred million tons, the purity of CO 2 in flue gas is usually only 25% -35%, the current alumina factories, boilers and lime kilns are always adjacently arranged, but the red mud and low-purity CO 2 are not cooperatively treated, and the resource waste and the environmental pressure superposition are caused. The existing red mud carbon fixation technology is mostly in an experimental stage, often depends on high-purity CO 2, and faces the problems of harsh reaction conditions, low carbon fixation efficiency, difficult amplification and the like, and the recycling utilization of the red mud in the fields of building materials, soil improvement and the like is also subject to the challenges of high alkalinity, heavy metal risk, low added value of products and the like. The existing technology lacks direct large-scale utilization of low-purity CO 2, high-valued product and system integration of full-flow intelligent regulation and control, and does not form an economically feasible industrial mode. Disclosure of Invention The invention aims to solve the problems that in the prior art, the red mud carbon fixation technology is in an experimental stage, often depends on high-purity CO 2, has harsh reaction conditions, low carbon fixation efficiency and is difficult to amplify, and provides a recycling system and method for scale CO-solidification of low-purity CO 2 by red mud. In order to achieve the above purpose, the present invention adopts the following technical scheme: A red mud scale synergistic solidification low-purity CO 2 recycling system comprises: The red mud pretreatment unit is used for mixing the red mud with water to prepare pumpable uniform slurry; the gas-liquid reaction unit is communicated with the red mud pretreatment unit and is used for carrying out countercurrent carbonation reaction on the red mud slurry and the gas containing carbon dioxide; The product separation and modification unit is communicated with the gas-liquid reaction unit and is used for dehydrating and separating the reacted solid-liquid mixture and crushing and modifying the solid product; The resource recovery unit is respectively communicated with the liquid outlet and the solid outlet of the product separation and modification unit and is used for recovering sodium carbonate products from the liquid and processing the modified solid products into building materials or soil amendments; And the intelligent regulation and control unit is in signal connection with the units and is used for intensively monitoring and controlling the operation parameters of the whole system. Preferably, the gas-liquid reaction unit comprises a plurality of efficient gas-liquid reaction towers which are arranged in parallel, wherein a pulse gas distribution device positioned at the bottom and a countercurrent contact spray system positioned at the top are arranged in the reaction towers, the diameter of air holes of the pulse gas distribution device is 0.5-1mm, the gas distribution uniformity error is less than or equal to 5%, and the spray coverage area of the countercurrent contact spray system is more than or equal to 95% of the inner cross section area of the towers. Preferably, the system further comprises a CO 2 pressurizing device for pressurizing the carbon dioxide-containing gas with the purity of 25-35% to 0.3-0.5MPa and then delivering the gas to the pulse gas distribution device. Preferably, the product separation and modification unit comprises a plurality of filter presses arranged in parallel and a modifier adding system, wherein the modifier adding system is used for adding a modifier accounting for 5-15% of the mass of the solid product into the dehydrated solid product, and the modifier is a compound system of fly ash and gypsum, and the compound ratio is 3:1. Preferably, the resource recovery unit comprises a wastewater recycling treatment system, the wastewater recycling treatment system adopts a prec