Technology and system for producing iron ore concentrate by iron ore chain grate machine-rotary kiln through shallow hydrogen metallurgy

Abstract

The invention relates to a technology and a system for producing an iron ore concentrate by an iron ore chain grate machine-rotary kiln through shallow hydrogen metallurgy. Iron ore of which the granularity is 40 mm or below is divided into three granular classes, wherein coarse-grain iron ore is dried and preheated through the chain grate machine to be added from the material adding end of the rotary kiln, high-volatility lignite is evenly sprayed and blown to be distributed in the length direction of the whole rotary kiln, middle-grain iron ore is sprayed and blown to the front section and the middle section of the shallow hydrogen metallurgy roasting area of the rotary kiln, and fine-grain iron ore is added into the rear section of the shallow hydrogen metallurgy roasting area and is processed through a shallow hydrogen metallurgy process to obtain iron ore concentrate. The chain grate machine is connected in front of a magnetization roasting rotary kiln in series, an early stage oxidizing roasting method and a later-stage reduction roasting method are adopted to further improve hydrogen utilization efficiency, roasting time is shortened, and the roasting quantity of the iron ore, the yield of the iron ore concentrate and a metal recovery rate can be greatly improved.

Description

technical field [0001] The invention belongs to the technical field of metallurgy and mineral engineering, and relates to an iron ore chain grate-rotary kiln shallow hydrogen metallurgy production process and system for iron concentrate. Background technique [0002] Among the iron ore resources, limonite, siderite, and sedimentary hematite are difficult to be effectively utilized by conventional beneficiation technology. They are converted into strong magnetic iron minerals by magnetization roasting process, and then separated by weak magnetic separation process. Separating iron-containing materials from gangue is an effective way to improve the utilization rate of such iron ore resources. At present, the common iron ore magnetization roasting technology at home and abroad is mainly the rotary kiln process. [0003] The traditional rotary kiln process mainly processes iron ore with a grain size of 0-15mm, that is, the whole grain size of 0-15mm powder ore enters the kiln f...

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Problems solved by technology

For example, in order to improve the utilization rate of reduced coal, part of the raw coal for reduction is directly sprayed into the roasting area of ​​the rotary kiln from the discharge end, part of the raw coal for reduction is still roasted by adding iron ore from the input end of the rotary kiln, and part of the raw coal for reduction is directly sprayed into the roasting area of ​​the rotary kiln. Spraying into the roasting area of ​​the rotary kiln can indeed improve the utilization rate of coal, but after the volatile matter is thermally decomposed in the material layer in this area, the reducing atmosphere inside the material layer is excessively increased, that is, the gas phase volume and h 2 content, which increases the over-reduction tendency of iron ore; at the same time, a large amount of combustible gas concentrates on the surface of the material layer and enters the combustion space of the rotary kiln to act as fuel, which further increases the temperature in this area, aggravates the "ring formation" in the kiln, and It has not fundamentally solved the problem of smooth production of rotary kiln and improvement of roasted ore quality

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