Method for efficiently separating low-ore grade and complicated iron ore

Abstract

The invention provides an efficient separation method for low-grade and complex iron ores. The method is characterized in that the complex iron ores of different grades and species are classified, so as to obtain lump ores and mineral powder which are balled, dried and preheated; reduction roasting, cooling, ball milling, magnetic separation, ball milling and magnetic separation or reverse flotation are performed in turn, so as to obtain iron ore concentrate or reduced iron powder; classification treatment is to crush and screen the iron ores with iron-containing grade between 50 and 56 percent and then dry and preheat obtained ores; fine-grained mineral powder is ground, washed, ground, deslimed and separated so as to obtain the iron ore concentrate and slime containing 58 to 60 percent of iron; the slime which is washed, deslimed, and separated is dewatered and dried and is added to and well mixed additives, so as to be balled then; the iron ores with the iron-containing grade between 40 and 50 percent are crushed and screened so as to obtain the lump ores which are directly dried and preheated, while the fine-grained mineral powder is obtained through dry-type grinding and then is added to and well mixed the additives so as to be balled then; and the iron ores with the iron-containing grade between 25 and 40 percent are crushed and screened so as to obtain the lump ores which are dried and preheated, while the fine-grained mineral powder is subjected to grinding, gravity separation or high-gradient magnetic separation and reverse flotation, so as to obtain coarse iron concentrate powder which is added to and well mixed with the additives and then is balled.

Description

technical field [0001] The invention relates to the field of iron and steel metallurgy, especially for low-grade limonite, low-grade fine-grained hematite, siderite or its mixed ore, or iron mine tailings with low iron grade, fine embedded particle size, and high content of harmful elements. A new sorting method for refractory iron ore. Background technique [0002] In recent years, the supply of iron ore in the world has become increasingly tight, and the price of iron ore has risen sharply. Therefore, making full use of low-grade fine-grained hematite, limonite or siderite resources at home and abroad or recycling iron-containing minerals in iron mine tailings to produce high-grade iron concentrate or direct reduced iron, as a blast furnace Ironmaking raw materials or electric furnace steelmaking raw materials have broad market and application prospects. [0003] There are abundant limonite (goethite) resources in the world, but its separation and enrichment is very diff...

AI Technical Summary

Problems solved by technology

[0003] There are abundant limonite (goethite) resources in the world, but its separation and enrichment is very difficult. For example, Australia is a country with large limonite resources, and only directly uses high-grade limonite powder or lump ore (iron grade> 56%), limonite with iron content less than 56% is discarded as waste rock. In order to reduce the alumina content in high-grade ore production, ore washing and desliming are used. Although the ore slime has a high iron content, it is also discarded as waste rock

China's limonite and siderite resources are also very large, but the iron grade is low and the content of harmful elements is high. Some separation processes have been developed for this, such as flotation, gravity separation, magnetic separation and their combined separation process, but Due to poor sorting effect and high cost, it is rarely used in production

The main reason is that limonite is hematite (or called goethite) containing crystal water, the ore structure is complex, it is easy to muddy in the grinding and sorting, the selectivity is poor, the technical and economic indicators are not ideal, and the separation The product is still limonite, with high content of crystal water and acid gangue silicon and aluminum, which is prone to thermal cracking during sintering and pelletizing, which seriously affects the output and quality of sinter and pellets, and is not conducive to strengthening blast furnace smelting

Siderite is a carbonate-containing mineral, which has very similar properties to carbonate minerals such as gangue mineral calcite, and is difficult to be enriched by traditional beneficiation methods

In addition, there are a large number of raw hematite ores with fine particle size and low iron content in China, and it is difficult to effectively sort them by traditional mineral processing technology

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