Oxidation-magnetization roasting system and process of refractory iron ore powder

Abstract

The invention discloses an oxidizing-magnetizing roasting system and technology for refractory iron ore powder, and belongs to the technical field of metallurgy and mineral engineering. The refractory iron ore powder undergoes oxidizing roasting fully inside an oxidizing roasting furnace and then enters a circulating fluidized bed reactor for undergoing reducing magnetizing roasting, and therefore fast magnetizing roasting of the refractory iron ore powder especially the refractory iron ore powder with the small disseminated grain size is realized; roasting tail gas is completely purified by a wet dust collector and a dehydrater and then enters a combustion chamber for being utilized, and therefore the scaffolding problem of the combustion chamber is solved, normal circulation of airflow inside the combustion chamber is guaranteed, and the whole magnetizing roasting reaction progress is accelerated to a certain extent; the iron ore powder is roasted at high temperature and preheats combustion air, so that the sensible heat of the roasted iron ore powder is recycled, and utilization of the sensible heat of the roasted iron ore powder is more reasonable and fuller; and the roasting tail gas preheats coal gas through an indirect heat exchanger, so that the sensible heat of the roasting tail gas is recycled, and the utilization rate of fuel is increased.

Description

technical field [0001] The invention belongs to the technical field of metallurgy and mineral engineering, and specifically relates to a system and a magnetization roasting process for oxidation-magnetization roasting of refractory iron ore powder using a circulating fluidized bed reactor. Magnetic separation of iron ore. Background technique [0002] 97% of my country's iron ore reserves are lean ore. Among them, iron ore resources that are difficult to be effectively processed by conventional gravity separation, magnetic separation and flotation techniques include limonite, siderite, and sedimentary hematite. There are nearly 20 billion tons. For these refractory iron ores, the weak magnetic iron oxides can be converted into strong magnetic artificial magnetite through magnetization roasting, and then the iron minerals and gangues can be separated by weak magnetic separation, which is a refractory iron ore. An effective method for ore sorting. [0003] At present, iron o...

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Problems solved by technology

[0004] The shaft furnace magnetization roasting process is a process for processing 15-100mm block iron ore in the furnace. There are the following deficiencies in the iron ore magnetization roasting process: (1) The iron ore that can be processed has a large particle size and a specific surface area. small, with CO and H 2 (2) The reduction degree of the surface layer of the lump ore is higher than that of the interior, and the larger the particle size, the more serious the uneven reduction phenomenon; (3) The particle size of the lump ore entering the furnace is uneven, and there are small particle sizes The overall over-reduction of lump ore and the overall under-reduction of large-size lump ore

The disadvantages of this technical solution are: first, the iron ore powder is not fully oxidized and roasted before entering the circulating fluidized bed reactor, and the temperature of the iron ore powder is low, so it is difficult to realize the iron ore powder, especially the iron ore with finer particle size The rapid magnetization roasting of stone powder; the second is that the incompletely purified roasting tail gas is burned in the combustion chamber, and the dust is easily brought into the combustion chamber to cause nodules; the third is only through the exchange of cold gas and high-temperature roasted iron ore powder in the cyclone cooler. Recovery of sensible heat by way of heating is insufficient for the recovery and utilization of sensible heat of high-temperature roasted ore, and the utilization of sensible heat for roasting tail gas is not sufficient.

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