Novel heat accumulating type tunnel kiln for magnetizing roasting or direct reduction of iron ore

Abstract

The invention relates to a novel heat accumulating type tunnel kiln for magnetizing roasting or direct reduction of iron ore. The content of the invention is that (1) in the novel heat accumulating type tunnel kiln, original reverse air suction of the kiln head and kiln tail ends is changed into air suction at one end in the kiln tail direction, and an induced draft fan is not arranged in the kiln head direction; (2) the tunnel kiln from the kiln head to the kiln tail is divided into a roasting section I, a roasting section II and a cooling section, and a preheating section is not arranged; and (3) after flue gas exhausted from all the sections of the tunnel kiln enters a secondary combustion chamber to be burnt, the flue gas is sent into a heat accumulating type heat exchanger for waste heat recycling, and generated hot air is blown into the kiln as a heating heat source and high-temperature combustion-supporting air. According to the novel heat accumulating type tunnel kiln, the purposes that the waste heat of high-temperature flue gas in roasting of an iron ore tunnel kiln is recycled, the energy consumption is reduced, the yield is increased, and the length of a kiln body is shortened are achieved.

Description

technical field [0001] The invention belongs to the technical field of metallurgy and mineral engineering, and relates to a novel regenerative tunnel kiln for iron ore magnetization roasting or direct reduction. Background technique [0002] At present, the iron ore tunnel kiln direct reduction process is to put iron concentrate, coal powder, and limestone powder into the reduction tank according to a certain proportion and charging method, and then put the tank on the tank car and push it into the strip tunnel kiln. Or put the tank directly into the annular wheel kiln. After the material tank is heated, roasted and cooled at about 1150°C, direct reduced iron can be obtained. The direct reduction process of iron ore coal-based tunnel kiln has the characteristics of mature technology and simple operation, but there are problems such as small production capacity of a single machine, high energy consumption, and serious environmental pollution in the direct reduction of iron or...

AI Technical Summary

Problems solved by technology

[0004] In the current iron ore tunnel kiln direct reduction process, in order to balance the furnace pressure distribution along the kiln length in the tunnel kiln and reduce the phenomenon of positive pressure fire and negative pressure suction in the kiln, discharge from both ends of the tunnel kiln is adopted. The smoke method, because the coal in the mine-coal mixture will have volatile components at a lower temperature (300-500 ° C), resulting in a certain amount of volatile coal combustible components contained in the flue gas discharged from the kiln entry end of the tunnel kiln. Combustible volatile components of coal cannot be combusted at lower temperatures, and are directly discharged into the atmosphere, causing environmental pollution and energy waste

In addition, the tunnel kiln is generally equipped with a long preheating section to recover the waste heat of the flue gas discharged from the feed end, which shortens the effective high-temperature roasting time and reduces the production capacity of the tunnel kiln.

[0005] In the current iron ore tunnel kiln roasting process, gas fuel is generally used for heating materials. For areas where gas fuel is scarce, iron ore tunnel kiln roasting is subject to certain restrictions. Generally, supporting construction is required to supply gas fuel to the tunnel kiln. Gas furnace, which increases the cost of iron ore tunnel kiln roasting and brings a series of environmental problems

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