CN-122012931-A - Process for dealkalizing and deep reducing red mud by gradient temperature control treatment

CN122012931ACN 122012931 ACN122012931 ACN 122012931ACN-122012931-A

Abstract

The invention discloses a process for dealkalizing and deeply reducing red mud by step temperature control treatment, which comprises the following steps of 1) accurately metering raw materials and grinding, 2) conveying the ground raw materials into a red mud stirrer, stirring at a gradient rotating speed, 3) conveying the stirred and mixed raw materials into a granulator for granulating, pressing the materials into granular materials with the particle size of 5-15mm, 4) conveying the granular materials into a dealkalized solid-phase reaction device, forming the granular materials after solid-phase reaction in a reducing atmosphere, 5) conveying the granular materials after solid-phase reaction into a cooler, adopting a nitrogen direct circulation cooling method, then cooling the furnace slowly, 6) crushing the cooled materials to the particle size of less than 5mm by a crusher, and 7) carrying out magnetic separation on the ground powder by a high-gradient magnetic separator. The invention realizes the high-efficiency dealkalization and iron element reduction separation through high Wen Tuojian pre-reduction and high-temperature deep reduction melting separation.

Inventors

MA KAI
LIN LIPING
MA JIANG
LIU XIUMEI
WANG XUAN
MENG QINGLIAN
MA LIANTAO
CAO JIANWEI

Assignees

山东明通环境科技股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260213

Claims (6)

1. The process for dealkalizing and deeply reducing red mud by step temperature control treatment is characterized by comprising the following steps of: 1) Accurately metering raw materials and grinding, namely taking pretreated red mud as a base material, fixing a reducing agent with carbon content more than or equal to 70%, wherein a composite additive is selected as an additive, and the mass ratio of the red mud to the reducing agent to the composite additive is 100:20-30:5-10; 2) Feeding the ground raw materials into a red mud stirrer, and stirring at a gradient rotating speed to ensure that the mixing variation coefficient of the materials is less than or equal to 8%; 3) Feeding the stirred and mixed raw materials into a granulator for granulation, and pressing the materials into granular materials with the particle size of 5-15 mm; 4) Feeding the granular materials into a dealkalization solid-phase reaction device, controlling the reaction temperature to 850 ℃ plus or minus 20 ℃ under the reduction atmosphere, and removing alkali metals in the materials for 2-4 hours to form granular materials after solid-phase reaction; 5) Feeding the solid-phase reacted granular material into a cooler, adopting a nitrogen direct circulation cooling method, controlling the cooling temperature to be reduced from 900 ℃ to 150 ℃ or less in a gradient manner, and cooling for 1.5-3 hours; 6) Crushing the cooled material by a crusher until the particle size is less than 5mm, and enabling the crushed finished material to enter a grinding section to grind the material to 200-400 meshes; 7) And (5) carrying out magnetic separation on the powder after grinding by a high-gradient magnetic separator.
2. The process for dealkalizing and deeply reducing red mud by step temperature control treatment according to claim 1, wherein in the step 1), the reducing agent is coke powder with fixed carbon content of 75%, the composite additive is bentonite with bonding strength of 0.6-0.8MPa, and the mass ratio of the red mud, the coke powder and the bentonite is 100:25-30:6-8.
3. The process for dealkalizing and deeply reducing red mud by step temperature control treatment according to claim 1, wherein in the step 2), a vertical turbulence stirrer is adopted, a stirring shaft is provided with 3-5 layers of paddles, the angle of each paddle is adjustable by 30-60 degrees, the stirring is carried out at a low speed of 200-300r/min for 3-5min, then at a high speed of 300-500r/min for 8-10min, the material mixing variation coefficient is ensured to be less than or equal to 8%, and the water content is adjusted to 14-16% by adding part of external water.
4. The process for dealkalizing and deeply reducing red mud by step temperature control treatment according to claim 1, wherein in the step 3), the prepared 5-15mm granular material is granulated by a granulator, and then is sent into a cylinder dryer with the internal temperature of 200-350 ℃ for drying intervention treatment, and the moisture is dried from <16% to <2%.
5. The process for dealkalizing and deeply reducing red mud by step temperature control treatment according to claim 1, wherein in the step 4), an anti-loop on-line control method is adopted to automatically control a solid phase reactor, a temperature detection unit of a multi-source sensing module acquires temperature signals of the inside and the outside of the solid phase reactor in real time, a process parameter acquisition unit acquires current and torque signals of a main driving motor, acquires smoke atmosphere component signals, and a visual image detection unit acquires material flow state and wall visual images of the inside of the solid phase reactor; the edge calculation and feature extraction module filters, reduces noise and normalizes signals collected by the multisource perception module, extracts feature values related to looping, wherein the feature values comprise axial temperature gradient, radial temperature deviation, high-temperature area and movement trend, fluctuation variance of driving torque, current trend slope, residence time of a preset temperature interval, pixel occupation ratio of texture roughness change and physical adhesion area of the inner wall surface of the solid-phase reactor, the looping risk assessment and decision module receives data of the edge calculation and feature extraction module, the risk fusion model calculates to obtain a looping risk index CRI by adopting a multivariable fusion algorithm based on weight distribution, the looping risk index is a continuous value between 0 and 100, the higher the value is, the larger the looping risk is, the control decision generation unit generates a targeted control instruction according to the looping risk index and the feature value with the largest contribution, the execution intervention module continuously monitors or early warns according to the control instruction, or performs intervention measures for adjusting material proportion and granularity through the material component and granularity adjusting unit, or adjusts operation temperature through the operation parameter adjusting unit, and evaluating the effect of the intervention measures through the analysis module, and recording a successful case by the storage module, wherein the successful case is used for optimizing parameters of a risk fusion model and controlling a control instruction of a control decision generation unit.
6. The process for dealkalizing and deeply reducing red mud by gradient temperature control treatment according to claim 5, wherein the looping risk index adopts a multivariable fusion algorithm based on weight distribution, and the expression is as follows: CRI=100 ×F fusion ([W t ×F t ,W v ×F v ,W p ×F p ];Θ) Wherein: f fusion (DEG) a top-level fusion function, and integrating the weighted feature values of each dimension into a single risk scalar; F t ,F v ,F p , respectively representing normalized characteristic values of three dimensions of a temperature field, a visual image and a process parameter, wherein each value range is [0,1]; W t ,W v ,W p , respectively corresponding to the dynamic weight coefficients of each dimension, and meeting the condition that W t +W v +W p =1; Fusing the internal parameter set of the function; multiplier 100, mapping the result to an intuitive risk index range of 0-100; The calculation method of the temperature field characteristic value F t comprises the following steps: F t =min(1,(ω 1 *N(ΔT)+ω 2 *N(G)+ω 3 *N(τ))/(ω 1 +ω 2 +ω 3 )) Wherein: N (Δt) =min (1, (Δt- Δt th )/ΔT scale ) local hot spot Wen Chayi degrees, Δt is the current hot spot to region average temperature difference, Δt th is the threshold for start-up concern, Δt scale is the scaling factor; N (G) = |G actual -G baseline |/G range , axial temperature gradient abnormality index, G actual is real-time calculation gradient, G baseline is history normal standard, and G range is normal fluctuation range; N (τ) = (τ measured -τ min )/(τ max -τ min ) the outer wall temperature conduction delay rate, τ measured is the measured delay time, τ min and τ max are the minimum and maximum theoretical delays; Omega 1 ,ω 2 ,ω 3 , sub-characteristic weights respectively corresponding to the weights of the local temperature, the axial temperature and the outer wall temperature, and presetting parameters; The calculation method of the visual image characteristic value F v comprises the following steps: F v =SVM(I t ,I {t-1} ,I {t-2} ,...) Analyzing a continuous endoscope image sequence by adopting a trained machine learning model, outputting a judging probability of a loop state by the model, compressing to be 0,1 by a Sigmoid function, and then taking the value as an F v value, and directly reflecting the visual evidence strength of wall adhesion, wherein the machine learning model is a Support Vector Machine (SVM); The calculation method of the characteristic value F p of the process parameter is as follows: F p =max(N(σ T ), N(φ), N(Δt)) Wherein: N (σ T )=σ Tcurrent /σ Tnormal : ratio of drive torque ripple variance, reflecting mechanical load variation; N (phi) = |phi actual -φ optimal |/φ tolerance , the deviation degree of the reduction potential reflects the abnormality of the chemical reaction environment, phi optimal is the optimal set value, and phi tolerance is the allowable deviation; N (Δt) = (t residence -t setpoint )/t range : change in residence time of the material in the preset temperature interval.

Description

Process for dealkalizing and deep reducing red mud by gradient temperature control treatment Technical Field The invention belongs to the technical field of industrial process control and solid waste recycling, and particularly relates to a process for dealkalizing and deep reducing red mud by gradient temperature control treatment. Background The red mud is a solid waste generated in the process of producing alumina from bauxite, has complex components, and contains higher elements such as iron, aluminum, silicon and the like and a certain amount of heavy metals and radioactive substances. With the continuous increase of global alumina production, the discharge amount of red mud is also rapidly increased, and huge pressure is brought to the environment. The large amount of accumulation of the red mud occupies a large amount of land resources, and the ecological system health is affected by the fact that water and soil are polluted by rain water leaching. The deep reduction and iron extraction of red mud is a complex physicochemical process involving high temperature, multiphase and multi-field coupling, and has a complex mechanism. The red mud contains alkali (mainly sodium) in various forms, which can be divided into soluble alkali and combined alkali, and the existing red mud treatment process cannot effectively remove alkali and cannot realize efficient dealkalization and reduction separation of iron elements. Disclosure of Invention The invention aims to solve the technical problem of providing a process for dealkalizing and deeply reducing red mud by gradient temperature control treatment, which realizes the reduction and separation of high-efficiency dealkalization and iron elements through high Wen Tuojian pre-reduction and high-temperature deep reduction and melting. In order to solve the technical problems, the invention provides a process for dealkalizing and deep reducing red mud by gradient temperature control treatment, which comprises the following steps: 1) Accurately metering raw materials and grinding, namely taking pretreated red mud as a base material, fixing a reducing agent with carbon content more than or equal to 70%, wherein a composite additive is selected as an additive, and the mass ratio of the red mud to the reducing agent to the composite additive is 100:20-30:5-10; 2) Feeding the ground raw materials into a red mud stirrer, and stirring at a gradient rotating speed to ensure that the mixing variation coefficient of the materials is less than or equal to 8%; 3) Feeding the stirred and mixed raw materials into a granulator for granulation, and pressing the materials into granular materials with the particle size of 5-15 mm; 4) Feeding the granular materials into a dealkalization solid-phase reaction device, controlling the reaction temperature to 850 ℃ plus or minus 20 ℃ under the reduction atmosphere, and removing alkali metals in the materials for 2-4 hours to form granular materials after solid-phase reaction; 5) Feeding the solid-phase reacted granular material into a cooler, adopting a nitrogen direct circulation cooling method, controlling the cooling temperature to be reduced from 900 ℃ to 150 ℃ or less in a gradient manner, and cooling for 1.5-3 hours; 6) Crushing the cooled material by a crusher until the particle size is less than 5mm, and enabling the crushed finished material to enter a grinding section to grind the material to 200-400 meshes; 7) And (5) carrying out magnetic separation on the powder after grinding by a high-gradient magnetic separator. 2. The process for dealkalizing and deeply reducing red mud by step temperature control treatment according to claim 1, wherein in the step 1), the reducing agent is coke powder with fixed carbon content of 75%, the composite additive is bentonite with bonding strength of 0.6-0.8MPa, and the mass ratio of the red mud, the coke powder and the bentonite is 100:25-30:6-8. 3. The process for dealkalizing and deeply reducing red mud by step temperature control treatment according to claim 1, wherein in the step 2), a vertical turbulence stirrer is adopted, a stirring shaft is provided with 3-5 layers of paddles, the angle of each paddle is adjustable by 30-60 degrees, the stirring is carried out at a low speed of 200-300r/min for 3-5min, then at a high speed of 300-500r/min for 8-10min, the material mixing variation coefficient is ensured to be less than or equal to 8%, and the water content is adjusted to 14-16% by adding part of external water. 4. The process for dealkalizing and deeply reducing red mud by step temperature control treatment according to claim 1, wherein in the step 3), the prepared 5-15mm granular material is granulated by a granulator, and then is sent into a cylinder dryer with the internal temperature of 200-350 ℃ for drying intervention treatment, and the moisture is dried from <16% to <2%. 5. The process for dealkalizing and deeply reducing red mud by step temperature control treatment according to