Refractory low-grade iron ore shaft furnace semi-coke added magnetizing roast process

Abstract

The invention relates to the technical fields of metallurgy and mineral engineering and discloses a refractory low-grade iron ore shaft furnace coal-based magnetizing roast process. The process disclosed by the invention comprises the following steps: dosing iron ore with the granularity of 15-50mm and semi-coke with the granularity of 15-30mm according to a ratio of 100:(2-5), uniformly mixing, and adding the mixture from the top of the shaft furnace; and allowing the mixed material flow to pass through a preheating zone of the shaft furnace and enter a heating zone, allowing one part of the semi-coke to participate in combustion in the shaft furnace, and allowing the mixed materials comprising the iron ore of which the temperature rises to 900-950 DEG C and the residual semi-coke to enter a reducing zone. At the reducing zone of the shaft furnace, reducing gas is introduced from the bottom of the furnace chamber, H2 and CO in the gas participate in iron ore reduction so as to generate water vapor and CO2, the water vapor and CO2 are contacted with the semi-coke to carry out a carbon gasification reaction in the iron ore in the rising process in the furnace chamber so as to produce H2 and CO, the reducing medium concentration in the shaft furnace is improved, and the amount of the reducing gas is reduced, so that the iron ore is fully reduced. After the iron ore is completely roasted at the reducing zone of the shaft furnace, fine iron ore concentrate with the iron grade of 56-60 percent is obtained by virtue of oxygen-free cooling, ore grinding and magnetic separation.

Description

technical field [0001] This patent relates to the technical field of metallurgy and mineral engineering, and discloses a shaft furnace coal-based magnetization roasting process for refractory low-grade iron ore that can increase the concentration of the reducing medium in the shaft furnace and reduce the amount of reducing gas. Background technique [0002] my country's metallurgical industry has been exhausted with the continuous mining of high-grade iron ore, and the price of iron ore has continued to rise. Low-grade iron ore and composite symbiotic iron ore have great utilization value and become an important source of development and utilization in the future. direction. [0003] The utilization of refractory low-grade iron ore is mainly to produce iron concentrate powder by strong magnetic separation process or magnetization roasting-grinding magnetic separation process. For refractory low-grade specularite ore, after the iron ore is ground and separated by strong magne...

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Problems solved by technology

[0006] (1) The quality of the output product is not high. Since the massive iron ore flows downward in the shaft furnace by its own gravity, this movement cannot be very uniform, even if the weight and size of each ore block are exactly the same, The lump ore near the furnace wall and the lump ore in the middle will also go down at different speeds, and the lagging and leading phenomena are more serious; The flue gas temperature distribution of the ore is not uniform. Generally, the temperature of the iron ore near the furnace wall is high, while the temperature of the iron ore near the middle of the furnace is low;

[0007] (2) Only gaseous fuel can be used. When the shaft furnace uses blast furnace gas as fuel, although it has the benefit of saving energy, it is difficult to reach the temperature required for iron ore magnetization roasting due to its low calorific value. The magnetization quality of the stone has a certain influence. If another gas generator is built to produce the gas required for the shaft furnace magnetization roasting, on the one hand, because the calorific value of the general generator gas is not high, it can only meet the requirements of the shaft furnace roasting. ; On the other hand, the investment of the gas generator is high and will bring new pollution

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