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A method for improving the grade of low-grade iron ore

A low-grade iron ore and grade-improving technology, applied in the direction of process efficiency improvement, etc., can solve the problems of low-grade iron ore that are difficult to effectively use, easy to form rings, high reduction temperature, etc.

Active Publication Date: 2016-09-28
CENT SOUTH UNIV +2
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  • Abstract
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Problems solved by technology

[0011] The purpose of the present invention is to develop a method for obtaining high-quality iron ore concentrate from low-grade iron ore, which can effectively solve the problems that low-grade iron ore is difficult to effectively use and that the reduction temperature is high, the reduction time is long, and the problem of easy condensation is high in the coal-based direct reduction process. It can effectively reduce the production cost of enterprises, 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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  • A method for improving the grade of low-grade iron ore

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Embodiment 1

[0042] Low-grade iron ore internal coal blending and additive granulation coal-based medium-temperature rapid reduction-magnetic separation method, the mass percentage of low-grade iron ore and coal less than 0.074mm after pretreatment is 52.32%, and the internal blending coal C / Fe ratio is 0.3 , additive NaCl accounted for 3.0% of the mass percentage of iron ore and bentonite accounted for 1.5% of the mass percentage of iron ore were mixed, disc granulated into small balls with a diameter of 3-8mm; after the granulated balls were dried, the rotary tube was used The time for the preheating temperature of the charge in the furnace to rise from 200°C to 920°C is 35 minutes; the rotary tube furnace is used to reduce and roast at 920°C for 20 minutes; the reduced roasted ore is ball milled for 20 minutes, the grinding concentration is 50%, and the magnetic field strength is 1.8KA / m magnetic separation; the result obtained is that the recovery rate of magnetic iron concentrate is 6...

Embodiment 2

[0044] Low-grade iron ore internal coal blending and additive granulation coal-based medium-temperature rapid reduction-magnetic separation method, the mass percentage of low-grade iron ore and coal less than 0.074mm after pretreatment is 65.01%, and the internal coal blending C / Fe ratio is 0.4 , additive NaCl accounted for 3.0% of the mass percentage of iron ore and bentonite accounted for 1.5% of the mass percentage of iron ore were mixed, disc granulated into small balls with a diameter of 3-8mm; after the granulated balls were dried, the rotary tube was used The time for the preheating temperature of the charge in the furnace to rise from 200°C to 950°C is 35 minutes; the rotary tube furnace is used to reduce and roast at 950°C for 20 minutes; the reduced roasted ore is ball milled for 20 minutes, the grinding concentration is 50%, and the magnetic field strength is 1.8KA / m magnetic separation; the result obtained is that the recovery rate of magnetic iron concentrate is 7...

Embodiment 3

[0046] Low-grade iron ore internal coal blending and additive granulation coal-based medium-temperature rapid reduction-magnetic separation method, the mass percentage of low-grade iron ore and coal less than 0.074mm after pretreatment is 71.41%, and the internal coal blending C / Fe ratio is 0.4 , additive NaCl accounted for 3.0% of the mass percentage of iron ore and bentonite accounted for 1.5% of the mass percentage of iron ore were mixed, disc granulated into small balls with a diameter of 3-8mm; after the granulated balls were dried, the rotary tube was used The time for the preheating temperature of the charge in the furnace to rise from 200°C to 950°C is 35 minutes; the rotary tube furnace is used to reduce and roast at 950°C for 10 minutes; the reduced roasted ore is ball milled for 20 minutes, the grinding concentration is 50%, and the magnetic field strength is 1.8KA / m magnetic separation; the result obtained is that the recovery rate of magnetic iron concentrate is 6...

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Abstract

The invention provides a method for improving the grade of low-grade iron ore. The method comprises the following steps: respectively pretreating low-grade iron ore and coal, adding coal dust and an additive according to a certain proportion and preparing small balls with particle sizes of 3 to 8 mm by using a disc or drum balling machine after the content of treated iron ore and coal with a particle size of 0.074 mm is more than 50%, wherein clay minerals in the low-grade iron ore are used as a binder, or a small amount of binders like bentonite is added and uniformly mixed with treated iron ore and coal; and drying the prepared balls with a belt or cylindrical dryer, carrying out reduction by using a rotary kiln and then successively carrying out cooling and magnetic separation so as to obtain high-grade iron ore concentrate. With the method, low-grade iron ore can be effectively treated, the high-grade iron ore concentrate is obtained through granulation of the coal and the additive, direct reduction and magnetic separation, and the characteristics of energy conservation, high efficiency and rapidness are obtained.

Description

technical field [0001] The invention relates to an iron ore reduction roasting-magnetic separation method, in particular to a low-grade iron ore internal coal blending and additive granulation coal-based medium-temperature rapid reduction-magnetic separation method. Background technique [0002] With the continuous development of the modern iron and steel industry, my country's iron and steel production has increased year by year, and the shortage of domestic high-quality iron ore has become increasingly serious. Mineral resources have become a "bottleneck" restricting the development of my country's iron and steel industry. With the rapid development of the iron and steel industry, China's demand for iron ore has increased sharply. Since 2009, China's imports of iron ore have increased by an average of 21.8% per year. The continuous increase in imports has also made China's dependence on iron ore imports continue In 2012, China's dependence on iron ore imports was about 63%...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B1/243C22B1/02
CPCY02P10/20
Inventor 黄柱成邹军姜涛范晓慧李光辉郭宇峰杨永斌张元波钟荣海
Owner CENT SOUTH UNIV