Low-grade iron ore direct reduction method

Abstract

The invention relates to a low-grade iron ore direct reduction method, which comprises: calculating and taking a certain amount of coal powder, an additive, a binder and water by adopting the dry basis mass of iron ore to be treated as reference; uniformly mixing the taken components, and completely wetting to obtain an internal matching coal; uniformly mixing the internal matching coal and iron ore particles to be treated, and granulating to obtain granulated pellets; directly conveying the obtained granulated pellets into a rotary kiln, carrying out drying, pre-heating, and reduction roasting to carry out coal base direct reduction so as to obtain a reduced material, cooling the reduced material in the absence of air, and carrying out dry magnetic separation to obtain the reduced roasting pellets and the residual carbon; and carrying out treatments such as ore grinding and magnetic separation on the reduced roasting pellets to obtain iron concentrate, or carrying out re-grinding and re-magnetic separation to obtain the reduced iron powder, wherein the obtained residual carbon can be recycled. With the method of the present invention, the low-grade iron ore can be effectively treated, the internal matching coal and the additive are used to granulate, the wet pellets enter the kiln, the coal base direct reduction is performed, the magnetic separation is performed to obtain the high-grade iron concentrate or the directly-reduced iron powder, and the method has characteristics of energy saving, high efficiency, and rapidness.

Description

Technical field [0001] The present invention relates to a method for direct reduction of low-grade iron ore, and in particular to a method for direct reduction and magnetic separation of low-grade iron ore based on coal blending and granulating wet balls into the kiln. Background technique [0002] With the rapid development of the steel industry, my country's steel production has increased year by year, and the problem of insufficient domestic supply of high-quality iron ore has become increasingly serious. Mineral resources have become a "bottleneck" restricting the development of my country's steel industry. China's demand for iron ore has increased sharply. In 2009 Since this year, China's iron ore import volume has grown at an average annual rate of 21.8%. The continuous increase in import volume has also made China's iron ore import dependence continue to increase. In 2012, China's iron ore import dependence was approximately 63%. In 2014, China's iron ore import depende...

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Problems solved by technology

[0012] The purpose of the present invention is to develop a method for direct reduction of low-grade iron ore, which can effectively solve the problems of low-grade iron ore being difficult to effectively utilize, high reduction temperature, long reduction time, easy ring formation and high cost in the coal-based direct reduction process. problems, thereby effectively reducing the production cost of enterprises, which can effectively alleviate the tight supply of high-quality iron ore resources and promote the development of China's iron and steel industry

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