Method used for extracting iron from red mud by drastic reduction and method used for preparing gel material from secondary tailings

A cementitious material and deep technology, applied in the field of comprehensive utilization of resources, can solve the problems of low-grade iron-containing red mud being economically unreasonable, increasing production costs, and high smelting temperature, so as to solve the problem of red mud stockpiling, easy control and process. simple method effect

Active Publication Date: 2013-11-20
UNIV OF SCI & TECH BEIJING +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In this method, the red mud pellets are directly smelted in a blast furnace, the melting temperature is high, and the energy consumption is large, which is economically unre...

Method used

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  • Method used for extracting iron from red mud by drastic reduction and method used for preparing gel material from secondary tailings

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] (1) Deep reduction and iron extraction. Red mud contains 37.10% iron and contains Al 2 o 3 17.10%, containing SiO 2 7.46%, including CaO1.69%. Deep reduction conditions: red mud: coke: CaO=100:11:5, mixed evenly and kept at a reduction temperature of 1250°C for 60 minutes, then taken out and cooled naturally; Grinding at a grinding concentration of 65% to a fineness of -0.074 mm greater than 90%, the magnetic field strength is 111.44kA m -1 Under the conditions of magnetic separation, reduced iron powder with an iron grade of 91.23% and an iron recovery rate of 93.13% was obtained. Among them, the fixed carbon content of coke is 85.43%, the ash content is 12.5%, the volatile content is 1.21%, and the moisture content is 11.68%.

[0016] (2) Preparation of cementitious material from secondary tailings: filter and dry the secondary tailings after wet grinding and weak magnetic separation in step (1) and mix with blast furnace slag, cement clinker, activator and early...

Embodiment 2

[0018] (1) Deep reduction and iron extraction. Red mud contains 39.04% iron and contains Al 2 o 3 13.16%, containing SiO 2 8.02%, containing CaO1.55%. Deep reduction conditions: red mud: bituminous coal: CaO=100:17.5:12.5, mixed evenly and kept at a reduction temperature of 1350°C for 50 minutes, then taken out and cooled naturally; Grinding at a grinding concentration of 65% to a fineness of -0.074 mm greater than 90%, the magnetic field strength is 111.44kA m -1 Under the condition of magnetic separation, the reduced iron powder with iron grade of 92.58% and iron recovery rate of 95.05% was obtained. Among them, the fixed carbon content of bituminous coal is 67.83%, the ash content is 12.02%, the volatile content is 18.45%, and the moisture content is 1.48%.

[0019] (2) Preparation of cementitious material from secondary tailings: filter and dry the secondary tailings after wet grinding and weak magnetic separation in step (1) and mix with blast furnace slag, cement cl...

Embodiment 3

[0021] (1) Deep reduction and iron extraction. Red mud contains 37.10% iron and contains Al 2 o 3 17.10%, containing SiO 2 7.46%, including CaO1.69%. Deep reduction conditions: red mud: coke: CaF 2 : Na 2 CO 3 =100:11:5:10, after mixing evenly, keep it warm for 60min at the reduction temperature of 1250°C, then take it out and cool it naturally; grind the ore at a grinding concentration of 65% until the fineness -0.074mm is greater than 90%, and the magnetic field strength is 111.44kA·m -1 Under the conditions of magnetic separation, the reduced iron powder with an iron grade of 93.01% and an iron recovery rate of 92.84% was obtained. Among them, the fixed carbon content of coke is 85.43%, the ash content is 12.5%, the volatile content is 1.21%, and the moisture content is 11.68%.

[0022] (2) Preparation of cementitious material from secondary tailings: filter and dry the secondary tailings after wet grinding and weak magnetic separation in step (1) and mix with blast...

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Abstract

The invention discloses a method used for extracting iron from red mud by drastic reduction and a method used for preparing a gel material from secondary tailings, and belongs to the field of comprehensive utilization of resources. The method used for extracting iron from red mud by drastic reduction comprises following steps: Bayer process red mud is dried and crushed; the crushed red mud is mixed uniformly with a reducing agent and an auxiliary agent; the mixture is subjected to drastic reduction in a sealed container in a kiln with oxidizing atmosphere or reducing atmosphere; and the cooled material prepared by reduction reaction is subjected to wet milling and magnetic separation so as to obtain the iron powder of drastic reduction with iron grade of 90% or more, and iron recovery rate of 90% or more. The method used for preparing the gel material from secondary tailings comprises following step: the secondary tailings obtained after magnetic separation is dried, and are mixed uniformly with blast furnace slag, cement clinker, an exciting agent and an early strength agent; and then the secondary tailing gel material is prepared, wherein compressive strength and breaking strength of the secondary tailing gel material both meet the requirements of composite Portland cement 325 standard. According to the methods of the invention, the large amount of residual iron is recycled from the red mud, and the secondary tailings are used for preparation of the gel material, so that waste is transformed into valuables, the recovery of red mud iron resource is realized, and a problem of accumulation of red mud is solved.

Description

technical field [0001] The invention belongs to the field of comprehensive utilization of resources, and in particular relates to a method for preparing cementitious materials by deep reduction of Bayer process red mud to extract iron and secondary tailings. Background technique [0002] Red mud is a red muddy strong alkaline solid waste that remains after the aluminum industry extracts alumina from bauxite. Due to the difference in ore grade, production method and technical level, the red mud output of different manufacturers is also different. Generally speaking, 1.0-2.5 tons of red mud will be produced for every 1 ton of alumina produced. According to incomplete estimates, the current annual discharge of red mud in the world is about 60 million tons, but its utilization rate is only about 15%. So far, no effective way to use red mud in large quantities has been found. Because a large amount of red mud cannot be recycled, most of them are stored in the yard by wet method,...

Claims

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Application Information

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IPC IPC(8): C21B13/00B03C1/015C04B7/14
CPCY02P40/10
Inventor 倪文范敦城贾岩崔卫华张以河李瑾王红玉伏程红仇夏杰刘佳
Owner UNIV OF SCI & TECH BEIJING
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