There are many kinds of minerals containing tantalum and niobium, among which tantalum-niobite with high tantalum content is more meaningful. In the past 20 years, due to the development of the military industry, the demand for metal tantalum has increased day by day, coupled with the needs of various other industries, so the output has also continued to increase. According to existing materials, the annual output of tantalum and niobium concentrate in the world has exceeded 1000t. Not all minerals containing tantalum and niobium can be separated by electric separation, only tantalite, heavy tantalite, tantalum tantalite, manganese tantalite, titanium niobium tantalite, titanium niobium pernasite and niobite, etc. It has good electrical conductivity and can be separated as a conductor in electrical separation, while pyrochlore and fine spar are poor conductors and cannot be separated by electrical separation.
In the world, the raw ore grades of tantalum and niobium ore produced in countries such as Africa, Nigeria and South Africa are high (more than an order of magnitude higher than that in China). In addition, Malaysia, the Philippines, India and Thailand also recovered a part of tantalum-niobium iron ore from the placer, and the content of the original ore is not high. The output of the Soviet Union is also increasing, and they attach great importance to research and production in this area.
There are many resources of tantalum and niobium ore in my country, some of which are primary pegmatite granite deposits, and some are pegmatite granite weathered deposits and placer deposits. selected to obtain the final tantalum-niobium concentrate. At present, it is required in China that concentrates contain (Ta, Nb) 2O5> 40% or more, and tantalum (Ta2O5) is more than 20%. However, in the currently mined ores, niobium iron ore accounts for a large proportion, while niobium contains a large proportion of iron ore. The performance is far inferior to tantalum.
According to the situation in my country, the coarse concentrate obtained from the primary tantalum and niobium ore after gravity separation contains about 2~4% (Ta, Nb)-2O5, and also contains pyrite, tourmaline and bismuth ore. A large amount of gangue minerals are Garnet, followed by quartz, feldspar and mica. Using strong magnetic separation efficiency is not high, mainly garnet is also a weak magnetic mineral, its magnetic properties are similar to tantalum niobium ore, it is difficult to separate them effectively. With Φ120×1500mm high-voltage electric separator, the sorting effect is poor or cannot be sorted.
DXJ type Φ320×900mm high-pressure drum-type electro-separator has been applied in some domestic tantalum-niobium ores (such as Xinjiang concentrator, etc.), and generally obtained good results. In the rough concentrate, tantalum-niobium ore belongs to conductor ore, while a large amount of garnet, quartz, feldspar, mica and zircon belong to non-conductor ore, so it can be effectively separated by electric separation. After high-voltage electro-separation is used in combination with the above process, the total recovery rate of tantalum and niobium can be increased by more than 15% compared with that before the use of magnetic separation (magnetic separation). Recovery rate.
The actual production process of tantalum-niobite in the Soviet Union is described below. Tantalum-niobite is symbiotic with other minerals such as cassiterite, zircon, ilmenite, garnet and monazite. The raw ore is placer, and heavy minerals are obtained after gravity separation. The drum type electric separator and the strong magnetic separator are used for selection, and the shaker is used for re-selection, etc., to obtain qualified tantalum-niobium concentrates.
 Narrow-level sieving is used in the process to improve the magnetic separation efficiency. The purpose of the first stage of magnetic separation is to separate titanium ore and manganese niobite with strong magnetic properties, so that non-magnetic minerals are not mixed with titanium and tantalum niobite. Then, the non-magnetic minerals stone and zircon are further enriched with a shaking table, and tantalum-niobium ore is enriched, so as to discharge a large amount of tailings. Finally, five concentrate products including ilmenite, niobium-tantalum ore, monazite, cassiterite and zircon are obtained. The concentrate grade and recovery rate are as follows: Ta2O5=20% ε=65~70 %
Cassiterite Grade Sn=49% ε=85~87%
The content of ilmenite (referring to minerals) 96% ε=94~96%
The electric separator CЭC-1000 drum type electric separator is used. The heating temperature of the ore for electric separation is 80~120℃, and the separation particle size is less than 1mm. As far as electrical separation is concerned, the recovery rate of niobium and tantalum operations is 94.15%, the recovery rate of cassiterite operations is 97.49%, and the recovery rate of zircon operations is 93.89% (all refer to minerals).
Some placer processing plants in Guangdong and other places in my country contain similar minerals, and the processes and equipment used are basically the same, and the beneficiation indicators vary. The difference between my country's situation and the Soviet Union is that there are too many niobium iron ore deposits, and there are few such deposits with high tantalum content.