Method for preparing iron ore concentrate and aluminum ore concentrate through suspension co-roasting of red mud and coal gangue

Abstract

The invention discloses a method for preparing iron ore concentrate and aluminum ore concentrate by suspension co-roasting of red mud and coal gangue. The method comprises the following steps of: (1)crushing and grinding coal gangue; (2) mixing a red mud raw material with the coal gangue powder; (3) conveying the mixed powder to a suspension high-temperature furnace, enabling the mixed powder tobe in a suspension state under the action of negative pressure and airflow, heating the mixed powder to 650-1000 DEG C, and dehydrating the mixed powder to form high-temperature powder; (4) enabling the high-temperature powder to enter a cyclone separator, cooling to 600-950 DEG C to form a dehydrated material, and enabling the dehydrated material to enter a suspension roasting reducer; (5) introducing air and nitrogen into the suspension roasting reducer to enable the dehydrated material to be in a suspension state, cooling to 500-800 DEG C, reacting, and discharging the residual solid material as a reduction material; and (6) cooling the reduction material, grinding, and carrying out low-intensity magnetic separation to obtain magnetic iron ore concentrate and non-magnetic aluminum ore concentrate. The method disclosed by the invention is short and efficient in process, low in energy consumption, low in treatment cost, good in economy, environment-friendly and easy to realize large-scale industrial application.

Description

technical field [0001] The invention relates to the technical field of mineral processing and environmental protection, in particular to a method for preparing iron concentrate and aluminum concentrate by suspending and co-roasting red mud and coal gangue. Background technique [0002] Red mud is a reddish-brown strongly alkaline fine-grained waste slag discharged during the production of alumina. At present, most of the red mud is stockpiled and disposed of, which not only occupies land, pollutes soil, water and air, but also causes a lot of waste of useful metals; the stockpiling of red mud causes The safety, environment and ecological problems seriously threaten the sustainable development of the alumina industry. [0003] Coal gangue is solid waste discharged during coal mining and coal washing, accounting for about 10-20% of the total coal output. At present, the annual discharge of coal gangue in the global coal mining industry is about 350 million tons; long-term sto...

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Problems solved by technology

[0005] At present, there are few patents on the mixed utilization of red mud and coal gangue, which are generally used to prepare glass-ceramics, bricks, roadbed materials and cement, etc., realizing the reuse of solid waste such as red mud and coal gangue, but causing iron and Great loss and waste of aluminum resources; patent CN201310337154.5 discloses a method of using red mud to activate gangue and / or fly ash, and proposes to combine gangue and / or fly ash with red mud and Na 2 CO 3 Batching, then acid leaching to extract alumina after sintering at 600-1000°C, this patent reduces the consumption of activation aid alkali and realizes the synergistic treatment of red mud and coal gangue / or fly ash, but ignores the The fixed carbon in red mud and the existence of a large amount of iron oxide in red mud waste carbon resources and iron resources; currently, strong magnetic separation or direct reduction / smelting-magnetic separation are mostly used to separate iron minerals in red mud, and the iron recovery rate of strong magnetic separation Extremely low, the direct reduction smelting-magnetic separation method has the disadvantages of high energy consumption and large consumption of reducing agent

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