Manganese is a gray metal, hard and brittle, with a density of 7.4 , a melting point of 1,244 °C , and a boiling point of 2097 °C . There are four allotropes of manganese, and the crystal structure changes with temperature. Alpha- manganese is stable below 710 °C , and is a body-centered cubic lattice. At 710 °C , it is transformed into β- manganese, which is a slightly complex cuboidal lattice. When it is heated to 1070 °C , γ- manganese occurs, which is a face-centered cubic lattice. When it reaches 1140 °C, it turns into δ manganese, which is also the body-centered cubic lattice. Metal manganese burns like iron in humid oxygen or air. Manganese dissolves in dilute acid to form divalent salts and produces hydrogen gas; in the case of heating, manganese reacts with gases such as fluorine, chlorine, and bromine.
There are about 150 kinds of manganese-containing minerals known in nature, which are oxides, carbonates, silicates, sulfides, borates, tungstates, and phosphates. However, there are not many minerals with high manganese content. Common manganese minerals mainly include: pyrolusite, hard manganese ore, hydromanganese ore, argentite, brown manganese ore, rhodochrosite, pyriticite, and metal manganese is smelted by electric furnace smelting method. Aluminothermic reduction and electrolysis. Manganese is mainly used for deoxidizers and desulfurizers in the ironmaking and steelmaking processes, as well as additives for the production of superalloys, stainless steels, non-ferrous metal alloys and low-carbon high-strength steels; most of which are used to produce aluminum-manganese alloys, Stainless steel and stainless steel electrodes and so on. Manganese dioxide is an important raw material for the manufacture of dry batteries.
World reserves of manganese 680000000 T (manganese metal content, the same below), reserve base t. Which ranks first in South Africa, reserve base of 4 billion t; down followed by Ukraine 5 t;.. Gabon 1 t;. Australia 0 7.2 billion t;. Brazil 0 5.6 billion t; Georgia, 0 4.9 billion t;. India 0 3.6 billion t. If China's A+B+C reserves are compared with the reserves of foreign countries, China ranks in Georgia, and before India, it ranks sixth. Â Â
The distribution of manganese ore resources in China is unbalanced. The scale of the deposits is mostly medium and small, the ore quality is poor and the ore is mainly dominated. The ore components are complex, and the deposits are mostly sedimentary or sedimentary metamorphic, and the mining conditions are complex. The manganese mines that have been identified in China are distributed in 21 provinces, cities and autonomous regions in the country, of which Guangxi and Hunan are the most important, followed by Guizhou, Yunnan, Sichuan, Liaoning, Hubei, and Shaanxi. There are 8 regions where China's manganese ore reserves are relatively concentrated: (1) Southwest Guangxi, including Daxin, Jingxi, Tianhe, Debao, Fusui and other counties. (2) The Xiang, Sui and Chuan triangle areas include Hunan Huayuan, Guizhou Songtao, and Xiushan in Sichuan. (3) Zunyi, Guizhou Province, including Zunyi City and Zunyi County. (4) Chaoyang District , Liaoning. (5) Southeast Yunnan includes counties (cities) such as Lushan, Wenshan, Jianshui, Shiping, Mengzi, Kaiyuan and Gejiu. (6) Central Hunan, including Ningxiang, Yiyang, Xiangtan, Xiangxiang, Shaoyang, Shaodong, Xinshao, Taojiang and Wuyuan counties (cities). (7) Yongzhou-Dongxian County, Hunan Province, with two manganese mines, Dongxiang Bridge in Yongzhou and Houjiang Bridge in Dao County. (8) Shaanxi Hanzhong - Dabashan region, including Hankou, Xixiang, Ziyang, Ningqiang, Zhenba and Chengkou counties (cities) in Shaanxi. The reserves of retained manganese in the above eight regions accounted for 82% of the country's total reserves, which is an important raw material base for manganese mining in China.
Throughout China's manganese ore types, resource distribution, geological characteristics, and technical and economic conditions, there are the following characteristics:
1. uneven distribution of manganese ore resources
Although 21 provinces, municipalities and autonomous regions in China have identified manganese ore, they are mostly distributed in the southern region, especially Guangxi and Hunan provinces and districts, accounting for 56% of the country’s manganese ore reserves, and thus formed in the exploitation of manganese ore resources. Take Guangxi and Hunan as the main pattern.
2. The scale deposits are mostly medium and small
Of the 213 manganese mines in China, only 7 are large and the rest are medium and small deposits, which makes it difficult to fully utilize modern industrial technologies for mining. Over the years, more than 80% of the manganese ore production has come from local middle and small mines and mined mountains.
3. Poor quality ores and ore mainly lean
Reserves of manganese, manganese-rich (more than 30% manganese oxide ore, manganese carbonate ore than 25%) reserves only 6.4%, and there remains a need for manganese ore portion of the fat in the use of industrial processes. Poor manganese ore reserves accounted for 93.6% of total reserves. Due to the low grade of manganese ore, high impurity content and fine grain size, the technical processing performance is not ideal.
4. ORE COMPONENT complex
High-phosphorus, high-iron-manganese ores and manganese ores with accompanying (co-)producing metals and other impurities account for a large proportion of manganese ore reserves in China. For example, the southern Sinian “ Xiangtan type †manganese ore is more than 100 million tons . The reserves belong to manganese ore with high phosphorus content.
5. Ore complex structure, fine particle size
The process mineralogy of some manganese ores in Hunan, Guangxi, Guizhou, Fujian and Yunnan, which are the main manganese producing areas in China, shows that the vast majority of manganese deposits are fine-grained or fine-grained inlays, thus increasing the difficulty of sorting.
6. Sedimentary deposits are metamorphic or sedimentary, complicated mining conditions
About 80% of the manganese ore in China is of sedimentary or sedimentary metamorphic type. This type of ore deposit has a wide distribution area. The ore body is thin and multi-layered, gently inclined, and has a deep burial depth. It requires underground mining and has poor mining technology conditions. The reserves suitable for open-pit mining account for only 6% of the country's total reserves.