Chinese name: manganese ore mbth: manganese ore element symbol: Mn atomic number: 25 Main uses: metallurgical industry, laboratory catalyst, etc. Categories: mineral introduction, mineral raw materials, economic indicators, brief history of mining industry, mineral processing methods, human influence, physiological functions, profit and loss and health, related information, manganese poisoning, nutrition perspective, technological methods, mineral raw materials introduction Manganese is the eighth in the fourth cycle of the periodic table. Manganese has valence states II, III, IV and VII in nature, among which valence states II and IV are the most common. Manganese oxidizes easily in air. Under heating conditions, powdered manganese can combine with chlorine, bromine, phosphorus, sulfur, silicon and carbon. Manganese has a strong lithophile in the earth's lithosphere and silicate meteorites, but it has a strong oxygen affinity in the upper lithosphere. Although manganese and iron have many similar chemical properties in lithosphere and meteorites, manganese does not love iron. There are about 150 kinds of manganese-bearing minerals known in nature, which belong to oxides, carbonates, silicates, sulfides, borates, tungstates, phosphates and so on. But there are not many minerals with high manganese content. Several common manganese minerals are described as follows. (1) pyrolusite is tetragonal, with fine columnar or acicular crystals, usually in the form of massive and powdery aggregates. The color and stripes are black. Gloss and hardness depend on the thickness and morphology of the crystal. The crystallized ones have semi-metallic luster and high hardness, while the aphanitic blocks and powders have dim luster, low hardness and are easy to get dirty. The specific gravity is around 5. Pyrolusite is mainly formed by sedimentation and is one of the main components of deposited manganese ore. In the oxidation zone of manganese deposits, all primary low-priced manganese minerals can also be oxidized into pyrolusite. Pyrolusite is a very common mineral in manganese ore and an important mineral raw material for manganese smelting. (2) The monoclinic system of pyrolusite is rare, usually in the form of stalactite, kidney, grape aggregate, or dense block or dendritic. The color and stripes are black. Semimetallic luster. The hardness is 4 ~ 6 and the specific gravity is 4.4 ~ 4.7. Hard manganese ore is mainly an external cause, which is found in manganese deposits and oxidation zones of deposited manganese ores. It is also a common manganese ore in manganese ore and an important mineral raw material for manganese smelting. (3) The monoclinic system of brucite is columnar with longitudinal stripes on the mask. In some manganese-bearing hydrothermal veins, it often appears in the form of crystal clusters, and in sedimentary manganese deposits, it often appears in the form of cryptocrysts, or oolitic or stalactite aggregates. The mineral color is black and the stripes are brown. Semimetallic luster. The hardness is 3 ~ 4 and the specific gravity is 4.2 ~ 4.3. Hydromanganese ore exists not only in some hydrothermal deposits of endogenous origin, but also in sedimentary manganese deposits of exogenous origin, and is one of the mineral raw materials for manganese smelting. (4) houseman stone tetragonal system, with tetragonal biconical crystals, usually granular aggregates. The color is black, and the stripes are brownish orange or reddish brown. Semimetallic luster. The hardness is 5.5 and the specific gravity is 4.84. Hausmannite is formed by endogenesis or metamorphism. It is found in some contact metasomatic deposits, hydrothermal deposits and sedimentary metamorphic manganese ores, and is associated with brown manganese ore, which is also one of the mineral raw materials for manganese smelting. (5) The tetragonal system of brown manganese ore has biconical crystals and granular and massive aggregates. The minerals are black and the stripes are brown-black. Semimetallic luster. Hardness 6, specific gravity 4.7 ~ 5.0. Other features are the same as hausmannite. (6) The tetragonal system of rhodochrosite has rhombic crystals, which are usually granular, massive or nodular. Minerals are rosy, easy to oxidize and turn brown-black. Glass luster. The hardness is 3.5 ~ 4.5, and the specific gravity is 3.6 ~ 3.7. Endogenous rhodochrosite is common in some hydrothermal deposits and contact metasomatic deposits. Exogenous rhodochrosite is widely distributed in sedimentary manganese deposits. Rhodochrosite is an important mineral raw material for manganese smelting. (7) In the equiaxed crystal system of pyrolusite, the common simplex is cubic, octahedral and rhombic dodecahedron, and the aggregate is granular or massive. The color is steel gray to iron black, brown after weathering, with dark green stripes. Semimetallic luster. The hardness is 3.5 ~ 4, and the specific gravity is 3.9 ~ 4. 1. There are a large number of pyrolusite in sedimentary metamorphic manganese deposits, which is one of the mineral raw materials for manganese smelting. Economic indicators Manganese ore products include metallurgical manganese ore, manganese carbonate powder, manganese dioxide powder for chemical industry and manganese dioxide powder for batteries. Metallurgical departments, light industry departments and chemical departments that use manganese ore products have different requirements for the quality of manganese ore products according to their different uses. (1) Requirements of metallurgical industry for manganese ore quality. Ore used for steelmaking pig iron, manganese-containing pig iron and mirror iron. The iron content is not limited, and the total content of manganese and iron in the ore should be 40% ~ 50%. There are certain requirements for manganese content and manganese-iron ratio of ores in smelting various brands of manganese alloys. Smelting low-carbon ferromanganese, the ore contains 36% ~ 40% manganese, the ratio of ferromanganese is 6 ~ 8.5, and the ratio of phosphorus to manganese is 0.002 ~ 0.0036; When smelting ferromanganese, the manganese content of ore is 33% ~ 40%, the manganese-iron ratio is 3.8 ~ 7.8, and the phosphorus-manganese ratio is 0.002 ~ 0.005. Smelting Mn-Si alloy with Mn content of 29% ~ 35%, Mn-Fe ratio of 3.3 ~ 7.5 and P-Mn ratio of 0.0016 ~ 0.0048; Blast furnace ferromanganese, ore manganese content is 30%, ferromanganese ratio is 2 ~ 7, and phosphorus-manganese ratio is 0.005. (II) Quality requirements of chemical industry and light industry departments for manganese ore In chemical industry, manganese ore is mainly used to produce manganese dioxide, manganese sulfate and potassium permanganate, followed by manganese carbonate, manganese nitrate and manganese chloride. It is required that the content of MnO _ 2 in chemical-grade manganese dioxide powder should be more than 50%, Fe≤3%, al2o 3≤3%, CaO≤0.5%, MgO ≤ 0.1%when making manganese sulfate; When preparing potassium permanganate, iron ≤ 5%, silica ≤5% and alumina ≤ 4%. Natural manganese dioxide is the raw material for manufacturing dry batteries, and the higher the MnO 2 content, the better. The general ex-factory standard of harmful elements such as nickel, copper, cobalt and lead is copper.