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

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...

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, while producing metallic iron, the non-magnetic material also reaches or approaches the melting point, and the formed liquid non-magnetic material slag phase will block and bond the reactor, so the reduction The reaction process is difficult to carry out continuously

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