The types and properties of iron ore resources, the basic principles and technical methods of iron ore dressing, as well as the beneficiation process of different iron ores and the typical examples of dressing production. The main contents include: iron ore and iron ore, ore crushing and grinding, ore dressing technology and equipment, mineral processing, magnetite hematite ore dressing, ore dressing, mirror limonite processing and siderite ore dressing, ore dressing plant sampling and metal balance, chemical analysis of iron ore. Classification and main characteristics of iron ore The requirements for iron ore smelting, preparation and processing of iron ore smelting, coke in the blast furnace, the effect of coke and quality requirements, production of raw material preparation and sintering process of pellet production, etc.. 一、The chemical elements in the earth's crust of minerals, ores and rocks have been subjected to various geological processes. It has a uniform chemical composition and internal crystalline structure, with a certain physical and chemical properties. Ores and rocks are composed of minerals, which are aggregates of minerals. However, ore is a kind of material which can extract metals, metal compounds or useful minerals economically and reasonably. So the concept of ore and rock is relative. The ore is composed of useful minerals and gangue mineral composition. The ore can be used as useful mineral mineral, it is not the use of mineral and gangue minerals. 二、The classification and main characteristics of iron ore in nature, the metal state of the iron is very rare, generally with other elements into a compound. At present, there are more than 300 kinds of iron minerals, but only about 20 kinds of materials can be used as raw materials for iron and steel under the present technological conditions and technical level. According to the main characteristics of the iron containing minerals, according to their mineral composition, iron ore will usually be divided into magnetite, hematite, limonite, siderite four types.
磁铁矿 | 1 Magnetite: The main composition is Fe3O4, namely, Fe3O4, two +3 valence iron atom and a +2 1 price of iron atoms in each Fe3O4 molecule Fe2O3-FeO, oxygen atoms of -2 price, the mass fraction of Fe is about 72%. Isometric。 The single crystal is usually eight - dimensional, with less rhombohedral and twelve - dimensional. On the twelve sides of the diamond, the long diagonal direction is regular. Aggregates are dense and granular. The color is black, iron streak of black, semi metallic luster, opaque. Hardness 5.5 ~ 6.5. Specific gravity 4.9 ~ 5.2. Strong magnetism. Magnetite is the main iron ore containing magnetite, its chemical formula is Fe3O4, FeO=31%, Fe2O3=69%, the theoretical iron content of 72.4%. Sometimes this kind of ore containing TiO2 and V2O5 combined composite ore, called titanium magnetite or titanomagnetite alum. In the case of pure pure magnetite ore, the partial oxidation of magnetite to the semi - false hematite and false hematite is often caused by surface oxidation. The so-called false hematite is magnetite (Fe3O4) oxidation into hematite (Fe2O3), but it still retains the original shape of the magnetite, so called false hematite. Magnetite has a strong magnetism, the crystal is often eight sides, a small number of diamond shaped twelve body. Often aggregate into dense clumps, color streak iron black, semi metallic luster, relative density of 4.9 to 5.2, the hardness of 5.5 ~ 6, no cleavage, gangue is mainly quartz and silicate. Reduction is poor, generally contain harmful impurities sulfur and phosphorus. | 
赤铁矿 | 2.hematite Often contain the same class with the mixture of Ti, Al, Mn, Fe2+, Ca, Mg and a small amount of Ga and Co. Three square crystal, intact crystal rare. Crystalline hematite is steel grey, aphanitic earthy hematite is red. Streak of cherry red or bright red. Metal to semi metallic luster. Sometimes dull. Hardness 5 ~ 6. Specific gravity 5 ~ 5 Hematite hematite is anhydrous iron oxide ore, its chemical formula is Fe2O3, the theory of iron content is 70%. This kind of ore often forms a huge deposit in nature, it is the main ore of industrial production. Hematite iron content is 50% ~ 60%, sulfur and phosphorus containing harmful impurities is less, therefore, a good reduction of magnetite, hematite is a good raw material for iron smelting. Hematite has primary, there are wild, magnetite hematite after oxidation regeneration after the loss of magnetic, but still retains the crystal shape of magnetite martite, in martite often contain some residual magnetite. Sometimes also contain some weathering products of hematite hematite, such as limonite (2Fe2O3 - 3H2O). Hematite has a semi metallic luster, crystal are hardness of 5.5 ~ 6, the hardness of earthy hematite is very low, no cleavage, relative density of 4.9 to 5.3, only weak magnetic properties, the gangue silicate. | 
褐铁矿 | 3.limonite Limonite is hydrous ferric oxide ore is generated by the other ore after weathering, the most widely distributed in nature, but the large amount of buried deposits are rare. Its chemical formula is nFe2O3 • mH2O (n=1 ~ 3, m=1 ~ ~ 4). Limonite is actually composed of a needle and with different crystal water of iron and clay mixtures. In the vast majority of limonite iron minerals exist in the form of 2Fe2O3 - 3H2O. General brown iron ore is 37% ~ 55%, sometimes higher phosphorus. Absorbent limonite is very strong, generally absorbed a lot of water, remove the free water and crystal water in or into the blast furnace after heating, thus increasing the ore porosity, which greatly improves the ore reduction. So than reducing limonite, hematite and magnetite are better. At the same time, the iron content of the ore is increased accordingly.
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菱铁矿 | 4.siderite The main component is FeCO3, that is, ferrous carbonate, in which the mass fraction of Fe is about 49%, often containing Mg and Mn. Three party system. Common rhombohedral, often curved surface. The aggregate is coarse to fine. There was also a tubercular, grape shaped, earthy. Yellow, light brown yellow (dark brown after weathering), glass luster. Hardness 3.5 ~ 4.5, the proportion of about 3.96, due to the different content of Mg and Mn. Theoretical iron content 48.2%. In nature, there are less than the other three kinds of ore mining value of siderite. Siderite is easily oxidized limonite decomposition. General iron content is not high, but the decomposition of CO2 after heating, not only significantly increased the amount of iron and also become porous, good reducibility. |
Iron ore is the main raw material for blast furnace smelting, and its quality is closely related to the smelting process and the technical and economic indexes. The main factors determining the quality of iron ore are chemical composition, physical properties and metallurgical properties. The requirements for iron ore smelting in blast furnace is high iron content, less gangue, less harmful impurities, stable chemical composition, particle size uniformity, reducibility and certain mechanical strength and good performance. Grade of iron ore grade iron ore refers to the iron content of iron ore to TFe%. Grade is the main index to evaluate the quality of iron ore. Whether the ore has the value of exploitation, whether it can be directly into the furnace smelting and the value of the smelting, depends on the iron content of the ore. For the low iron content and iron content is high but harmful impurity content exceeds the specified requirements of ore or associated with beneficial components of iron ore, is required for mineral processing, selected by iron powder or pellet sintering ingredients can be processed into the furnace. Hematite ore dressing method, hematite beneficiation process, hematite ore dressing process:
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