Method for preparing high purity iron ore by reducing and magnetizing red mud in rotary kiln

A magnetization treatment, rotary kiln technology, applied in chemical instruments and methods, magnetic separation, solid separation, etc., can solve the problems of high energy consumption, difficult continuous reduction reaction process, poor reaction kinetics, etc., to achieve the effect of protecting the environment

Inactive Publication Date: 2012-08-08
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The reaction kinetics of red mud is poor during the low-temperature roasting process, the required reaction time is long, and the energy consumption is large
The second type of reduction magnetization roasting, when the temperature is controlled at 950 ° C ~ 1000 ° C,

Method used

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  • Method for preparing high purity iron ore by reducing and magnetizing red mud in rotary kiln
  • Method for preparing high purity iron ore by reducing and magnetizing red mud in rotary kiln

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0022] Example 1

[0023] (1) Filter and dehydrate the obtained red mud slurry through a filter press to obtain a relatively dry press cake, and then place the press cake in a drying drum, and the hot air used for drying the drum comes from the exhaust gas at the tail of the rotary kiln , the temperature of the exhaust gas is 900°C. After mixing the exhaust gas out of the rotary kiln with an equal volume of air, a medium-high temperature hot air of 400°C can be obtained. Using the medium-high temperature hot air of 400°C, the moisture content of the red mud cake in the drying drum is reduced to 3%. , get red mud block;

[0024] (2) Break the red mud lumps discharged from the drying drum into small pieces of ≤10mm, and then feed the red mud lumps of ≤10mm into the rotary kiln through the feeder. The temperature of the red mud lumps rises to 700°C, The composition of the feed temperature at 550°C is N 2 At 65%, H 2 O≤10%, CO% / (CO%+CO 2 %) In the mixture of 25% blast furnace ...

Example Embodiment

[0026] Example 2

[0027] (1) Place the obtained red mud in the drying drum. The hot air used for drying the drum comes from the waste gas at the tail of the rotary kiln. ℃ medium-high temperature hot air, use 450 ℃ medium-high temperature hot air to reduce the moisture content of the red mud cake in the drying drum to below 2%;

[0028] (2) Break the red mud lumps discharged from the drying drum into small pieces of ≤10mm, and then feed the red mud lumps of ≤10mm into the rotary kiln through the feeder. The temperature of the red mud lumps rises to 800°C, The inlet temperature is 650°C, and the composition requires N 2 At 60%, H 2 O≤10%, CO% / (CO%+CO 2 %) In the mixed gas of 22% generator gas and kiln exhaust gas, the reduction time of the red mud block in the rotary kiln is 30min, and the reduced magnetized red mud block is obtained, and more than 95% of the Fe in the red mud 2 o 3 Reduced to Fe by mixed gas 3 o 4 ; After the exhaust gas passes through three-quarters o...

Example Embodiment

[0030] Example 3

[0031](1) Put a certain amount of red mud in the drying drum for drying and further dehydration, and the moisture is reduced to 3%. Among them, the hot air used for drying the drum comes from the exhaust gas at the end of the rotary kiln, and the temperature of the exhaust gas is 925°C. After the waste gas exiting the rotary kiln is mixed with an equal volume of air, a medium-high temperature hot air of 425°C can be obtained, and the moisture of the red mud cake in the drying drum is reduced to below 3% by using the medium-high temperature hot air of 425°C;

[0032] (2) Break the red mud lumps discharged from the drying drum into small pieces of ≤10mm, and then feed the red mud lumps of ≤10mm into the rotary kiln through the feeder. Coal gas is fed into the kiln head, and the gas is a mixture of producer gas and kiln exhaust gas. The temperature of the mixed gas is 700°C, and the composition requirements are N 2 At 55%, H 2 O≤10%, CO% / (CO%+CO 2 %) at 20%,...

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Abstract

The invention discloses a method for preparing high purity iron ore by reducing and magnetizing red mud in a rotary kiln. The method comprises the following steps of: performing filter pressing and dehydration on red mud to obtain a filter-pressed cake; feeding the filter-pressed cake into a drying drum for drying; smashing into small blocks of less than or equal to 10 millimeters; adding red mud blocks of less than or equal to 10 millimeters into the rotary kiln through a charging machine; heating red mud in the rotary kiln to 700-850 DEG C; introducing coal gas into the kiln head of the rotary kiln to reduce over 95 percent of Fe2O3 in the red mud into Fe3O4; after 75 percent of reduced coal gas passes through the length direction of the rotary kiln, introducing air from the tail of the kiln for burning in the rotary kiln; and continuously heating red mud blocks newly-added into the rotary kiln by using combustion heat. Specific to the aim of preventing oxidation, reduced and magnetized red mud leaving the rotary kiln is directly cooled through water quenching, and is subjected to magnetic separating after cooling, so that high purity iron ore of which the grade is higher than or equal to 63 percent can be obtained. In the method for preparing high purity iron ore from red mud through a Bayer process, the recovering rate of iron elements is over 90 percent, and the high purity iron ore Al2O3 is less than 2.5 percent; and according to the flow, continuous production can be realized, high purity iron ore is produced by treating red mud, and the environment is protected.

Description

technical field [0001] The invention relates to a technical method of using a rotary kiln as the main equipment, using red mud as the main raw material, and controlling the appropriate reduction temperature and reduction atmosphere to separate the reduction product by magnetic separation, and then prepare iron fine powder. The technological process belongs to the field of material preparation. Background technique [0002] Red mud is an insoluble residue. From the production process, it can be divided into sintering method, Bayer method and combined method. Usually the main component of red mud is Fe 2 o 3 , SiO 2 , A1 2 o 3 And CaO etc. The main components of the red mud discharged by the sintering method and the combined method are roughly the same, which contains a large amount of 2CaO·SiO 2 and other active mineral components, which can be directly applied to the production of building materials; the red mud produced by the Bayer process is the residue after leachi...

Claims

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Application Information

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IPC IPC(8): B03C1/015C22B1/02
Inventor 佘雪峰薛庆国王静松张欣欣韩毅华王洪
Owner UNIV OF SCI & TECH BEIJING
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