As the lightest rare pro-MagmaElemental, lithium is usually enriched in residual magma in the late stage of magmatism. Can appear in a variety of rocks. In addition, salt lake brine, geothermal brine and oilfield brine all contain a lot of lithium. According to geological genesis, lithium ore can be divided into four types: granite pegmatite type, salt lake brine type, greisenized granite type and lithium-rich clay type. Among them, the first two are the most economically valuable lithium mines under the current industrial technology conditions.
(1) granite pegmatite type lithium deposit. These deposits are widely distributed and mainly occur in relatively stable geological structural units such as paleocrystalline shields and blocks. The metallogenic age is mainly Precambrian, but there are also Hercynian and Yanshan periods. Ore-bearing pegmatites can be divided into: ① banded pegmatite type lithium ore. The mineral composition of this kind of deposit is complex, and spodumene is the main source of high-quality low-iron lithium concentrate. These deposits can be subdivided into complex (Beryllium, Lithium, Cesium, Tantalum) rare metal pegmatite deposits (such as Lake Banika deposit, Bikita deposit in Zimbabwe, Karibibu deposit in Namibia, the largest cesium deposit in the world, and the super-large lithium, beryllium, tantalum, rare mica deposit in Keketuohai, Xinjiang, China with good zonation) and lithium-stannum pegmatite deposits (such as Greenbus deposit in Australia, also). ② Pegmatite deposit with no banded structure. This kind of pegmatite is basically a single-phase homogeneous rock mass, and this kind of lithium ore is usually an independent lithium ore or a lithium ore accompanied by a small amount of beryllium and tantalum. For example, many pegmatite deposits in the cassiterite-spodumene belt in North Carolina, USA, such as Kingshill deposit and Bessemer deposit, Lake Banika in Canada and Jiangxi, Hunan and Sichuan in China.
(2) Lithium mine in salt lake brine. This is an important lithium deposit. The lithium resources in salt lakes account for 66% of the world's lithium reserves and more than 80% of the world's lithium reserves. In closed basins, especially in plateau arid areas, lithium can be enriched in salt lake brine to form a lithium deposit with mining value, and lithium, potassium, sodium, magnesium, bromine and iodine can be comprehensively extracted. At present, the important lithium-containing salt lakes being developed and produced include Atacama in Chile, Mu Eirto in Hombre, Yinfeng Salt Lake in the United States and Qaidam Salt Lake in Qinghai, China. Important salt lakes that have not been developed are Wulongni in Bolivia and Zabuye Salt Lake in China and Tibet.
Generally speaking, the global lithium resources are extremely rich. According to the statistics of US Geological Survey, 1998 has proved that the global lithium resource reserves are 340× 104t, and the reserve base is 940× 104t. According to the output estimation of 1997, the world output can be guaranteed for 309 years. The world's lithium reserves and reserve bases are concentrated in South America and North America, as well as Bolivia, Chile, the United States, Canada, Australia and Zimbabwe. Among them, Bolivia and Chile account for about 89.3% of the world's reserves, and China has a huge resource prospect.
2) Beryllium
Beryllium is a typical pre-MagmaElemental, which can displace Si4 ++ into many silicate minerals during magmatic crystallization. Beryllium is mainly distributed in plagioclase, muscovite, nepheline and other rock-forming minerals. Beryllium can be enriched and form independent beryllium minerals (beryl, diaspore, beryl, etc. ) in residual magma, high temperature gas-liquid and medium temperature liquid environment, thus forming beryllium deposits with industrial significance. The mineralization of beryllium is mainly related to acid magmatism. There are many kinds, which can be roughly divided into five categories:
(1) beryl-bearing pegmatite beryllium deposit. These deposits are widely distributed and can be divided into beryl-muscovite pegmatite and composite rare metal pegmatite according to mineral assemblage. The former is widely distributed in Brazil, India, Argentina and the United States. The latter are distributed in Lake Banika in Argentina, Bikita in Zimbabwe, Karibibu in Namibia, Zaire, Madagascar, the former Soviet Union and Altay in Xinjiang, China. The sediments contain many beneficial components, such as lithium, tantalum, niobium and cesium. Beryl is often used as a product and by-product of complex rare metal deposits such as lithium deposits and niobium-tantalum deposits.
(2) Alkaline metasomatic beryllium deposits containing beryl. This is a new deposit type established after the beryllium ore body was circled in the rare metal deposit of Lake Sol, Canada in the early 1980s. The Suoerhu syenite body is located in a huge granite body and constitutes an alkaline complex. Five mineralization zones rich in niobium, tantalum, zirconium, yttrium, rare earth elements and beryllium were found in the contact zone between syenite and granite and in syenite.
(3) Bainite volcanic hydrothermal beryllium deposit. Beryllium deposits in Mount Spo, Sierra Blanca and Aguachili in northern Mexico all belong to this type. The main beryllium mineral is bainite. The distribution of beryllium in ore is very irregular. Besides beryllium, it also contains lithium, niobium, tantalum, tin, molybdenum, gallium, yttrium and yttrium rare earth elements.
(4) Dolomite deposit containing beryl. This kind of deposit is usually related to the mineralization of tungsten, molybdenum, tin and bismuth. According to the occurrence characteristics and mineral assemblage, it can be divided into two subtypes: metasomatic altered granite deposits containing beryl and chronological vein deposits containing beryl. The former is of great industrial significance, and the beryllium ore in boavista, Brazil may belong to this subclass. The latter is a composite deposit containing tungsten, tin, molybdenum and beryllium, and beryl is easy to be selected, which has certain industrial significance.
(5) Contact with carbonate beryllium deposit. These deposits occur in contact carbonate in granite outer contact zone, including beryllium-bearing skarn deposits and fluorite-ludwigite layered deposits. The former deposit is large in scale and high in beryllium content, but the mineral particles are fine and difficult to separate. Such deposits have been found in New Mexico and Alaska. The latter is located in the contact zone between granite and sedimentary strata with extremely complicated geological structure, and beryllium mineralization is superimposed on skarn. It is easy to separate ludwigite-beryl concentrate and fluorite concentrate by flotation.
The world is rich in beryllium resources. Brazil is the largest beryllium resource country, and India is the second. More than half of Australia's beryllium reserves are concentrated in Brockman beryl rare metal deposit, which is basically proved at 1985. Canada's beryllium reserves are mainly concentrated in the rare metal deposit of beryl in Lake Sol in the northwest, which will become the largest beryllium mine in western countries after it is put into production. Beryllium reserves in the United States are mainly concentrated in bertrandite deposit in Spool Mountain, Utah. 1988, Hegetiv deposit was discovered in Norway, which is considered as the first independent beryllium deposit with commercial value in Europe. It can be seen that beryllium resources are abundant and new discoveries are constantly made. According to the annual output of 600 tons of beryllium, beryllium reserves are enough for the world to mine for more than 600 years.
3) niobium
According to the statistics of the US Geological Survey, the world niobium reserves in 1998 were 350× 104t, and the reserve base was 420× 104t. Its proven reserves are highly concentrated, with more than 90% distributed in Brazil, followed by Canada, Zaire, Nigeria and other countries. In recent years, many countries, especially African countries, have discovered a large number of exploitable niobium reserves. The world's niobium reserves are highly guaranteed, which can meet the world's needs for hundreds of years. In nature, niobium is almost always associated with other minerals, especially tantalum, in the form of oxides. The main industrial types of niobium deposits are:
(1) carbonate weathering crust deposit. This is a rare metal deposit with high ore content, in which rare metals are highly enriched. It occupies an important position in niobium raw materials in the world, accounting for more than 90% of niobium resources. According to the development degree and stage of weathering crust, weathering crust deposits can be further divided into three categories: ① weathering crust deposits in hydromica, such as Belozimis Dan Coe deposit in Russia and Anji cobalt deposit in Brazil; (2) laterite weathering crust deposits, such as Alasha deposit in Brazil and Austrian deposit in katara; (3) Late epigenetic altered weathering crust deposits, such as Tomtor deposit in Russia. Finally, the ore-forming process of this kind of deposit is complicated, and the ore-forming materials have undergone many times of regeneration and enrichment, which is easy to form high-grade large rare metal deposits. These deposits are mainly produced in Brazil, Australia, Russia and Gabon, and the main niobium-bearing mineral is pyrochlore.
(2) Granite and granite pegmatite deposits containing columbite-tantalite. The proportion of niobium reserves in these deposits is very small, about 1%. The main tantalum-niobium mineral in ore is niobate titanate, which is often associated with cassiterite. At present, it is generally recovered as a by-product of cassiterite mining. Such deposits are found in many countries in south-central Africa, such as niobium-bearing iron ore granite and its slope deposits and residual deposits in the Jiaosi Plateau in northern Nigeria. In addition, there are such deposits in Brazil, Malaysia, Thailand, Mozambique and Zaire.
(3) placer. The placer containing niobium is generally small in scale, but easy to be mined and selected, and often coexists with tantalite and cassiterite, so it has certain economic significance and is mainly produced in the United States, Democratic Republic of Congo, Thailand, Malaysia, Australia and other countries.
Because of the particularity of niobium deposits, such as low grade ore, large proportion of most niobium minerals and stable physical and chemical properties, heavy sand method is an economical, simple and effective prospecting method for primary deposits. Radioactive survey and magnetic survey are very effective prospecting methods for carbonate rocks and their weathered crust deposits. In recent years, large-scale high-grade rare earth-yttrium-niobium-tantalum-phosphate deposits in weathering crust of carbonate rocks in Mount Wilder, Western Australia; A large number of niobium deposits have been discovered in Guxit, Chesra, Brazil and Gabon. Niobium deposits in China are mainly distributed in Inner Mongolia, Hubei, Guangdong and other places. Niobite is the main ore with relatively low quality, less than 1% of Brazilian grade, and many associated minerals.
4) Tantalum
According to the statistics of the US Geological Survey, the world tantalum reserves in 1998 were about 14000t, with a reserve base of 24000t, mainly distributed in Australia, Nigeria, Democratic Republic of Congo, Canada and Brazil. Tantalum resources in China are less, mainly distributed in Jiangxi, Xinjiang, Guangxi, Hunan and other places. Tantalum minerals are mostly complex oxides related to acid granite, which are generally stable under exogenous conditions. The metallogenic age of tantalum deposits is mainly CAMBRIAN, followed by Caledonian, Hercynian and Chimir periods. Scholars in the former Soviet Union divided tantalum deposits into three main types:
(1) Comprehensive rare metal pegmatite deposit. This kind of deposit can be divided into three series: ① Beryllium-lithium pegmatite series related to alkaline granite; ② Beryllium-lithium-cesium-tantalum pegmatite series related to mica granite; ③ F-Ta-Li pegmatite series related to super-acidic granite. The largest metallogenic scale is the first series of spodumene-albite and albite pegmatite deposits. This type is distributed in Brazil, Australia, Central Africa, South Africa, Canada and the former Soviet Union. The reserves of such deposits account for about 34% of tantalum reserves and 30% of the output of the western world. The Canadian Lake Banika deposit is one of the largest deposits in the world.
(2) Granite pegmatite weathering crust niobite-tantalite deposit. This linear weathering crust deposit on granite pegmatite is developed in Zaire, Brazil and Australia. They are small and medium-sized deposits with low tantalum content, but they are easy to mine and relatively economical, and they are important sources of tantalum, accounting for about 53% of the output in the western world.
(3) Niobite-tantalite deposit. Because niobite-tantalite is very brittle, the transportation distance of this kind of deposits from primary deposits is less than 7 kilometers, mostly 2 ~ 3 kilometers. Generally, it is accumulated in the slope deposits in granite parent rocks or pegmatite areas, and sometimes it is enriched in the weathering crust. The largest placer is the northern valley of Lugulu, Zaire. Brazil, Australia, Nigeria and the former Soviet Union also have this kind of placer.
The secondary tantalum deposits and their possible sources are: ① albite-greisen type columbite-tantalite deposit; (2) A comprehensive network vein deposit of albite rare metals; ③ Niobite deposits in weathering crust of alkaline granite; ④ Carbonate uranium pyrochlore deposit; ⑤ Uranium-bearing pyrochlore-Vogel deposit in carbonate weathering crust.
5) Zirconium
1992 The world zirconium (ZrO2 _ 2) reserves are 4900× 104t, and the reserve base is 5800× 104t. In addition, 6000× 104 tons of zircon resources have been discovered. The world is rich in zirconium resources, including Australia, South Africa, the former Soviet Union, the United States, India and Brazil.
Zirconium is a typical pro-MagmaElemental faction. Zirconium deposits include endogenetic deposits and exogenetic deposits, among which placer is the most important, accounting for 53% of the world's zirconium reserves, and more than 95% of zirconium concentrate comes from placer. Coastal sand deposits are the most important exogenous deposits, as well as residual and alluvial sand deposits and carbonate weathering crust deposits. Endogenous deposits of zirconium are mainly magmatic deposits, which are related to alkaline rocks. Most of these deposits occur in the Precambrian intermediate blocks in the paleoplatform area and Phanerozoic geosyncline area, and the reserves of deposits are generally only a few hundred thousand tons, and the reserves of zirconium deposits in the platform area can reach millions of tons. The main genetic types of zirconium deposits are: ① alkaline granite containing zircon; ② Alkaline rocks containing baddeleyite; ③ Anisotropic rocks; ④ baddeleyite vein in nepheline syenite; ⑤ Weathering crust of syenite containing baddeleyite vein; ⑥ Coastal placer (a small amount of inland zircon placer).
Liu Manhua believes that the world-famous exogenous and endogenous zirconium deposits and newly discovered new types of zirconium mineralization are: ① sand deposits on the east and west coasts of Australia; (2) Inland alluvial and residual sand deposits in Pitinga, Brazil; ③ baddeleyite deposits related to ultrabasic-alkaline-carbonate complexes, such as ParaBeauroy deposit in South Africa and Kovdor deposit in Russia; ④ Carbonate weathering crust type zirconium deposit coexisting with rare earth, niobium, tantalum and phosphate, such as Weiershan carbonate weathering crust deposit in Western Australia; ⑤ Vein and disseminated zirconium deposits in alkaline complex, such as Bossus-Das uranium-bearing zirconium deposit in Brazil; ⑥ New zirconium mineralization related to low-temperature hydrothermal process, such as zirconium mineralization formed by colloidal solution deposition at low temperature, has been discovered in central Kazakhstan and Russian Aldan in recent years. To sum up, ultrabasic rock alkali carbonate complex (including alkaline rock mass) is not only the source of secondary zirconium ore (weathering crust), but also the source of zirconium ore far from the complex related to ore-forming chemical zone. Therefore, when looking for zirconium deposits related to this kind of complex, we should not only pay attention to the complex itself, but also pay attention to the fact that being far away from the complex may become a favorable area for zirconium enrichment.
6) Rare earth metals
The world is rich in rare earth reserves. According to the statistics of the US Geological Survey, the world rare earth (REO) reserves and reserve bases are 10000× 104t and1000×104t respectively. Its reserves are highly concentrated, with China, the former Soviet Union, the United States, Australia and Malaysia accounting for 83.2% of the total reserves. At present, the light rare earth (cerium rare earth) used in industry is mainly extracted from bastnaesite and monazite, accounting for about 99% of the world's rare earth oxide (REO) output, while the heavy rare earth (yttrium rare earth) output is very small, mainly extracted from xenotime and beryl. The main producers of rare earth minerals in the world are China, the United States, Australia and India. The rare earth minerals in these countries account for 78% of the world's total output. China ranks first in the world in rare earth mineral resources. About 95% of the concentrate comes from Bayanobo Iron Mine in Baotou, Inner Mongolia, and the rest comes from ion-adsorbed rare earth ore and mixed rare earth concentrate in the south and Maoniuping rare earth mine in Mianning, Sichuan. The former Soviet Union is the most important producer of rare earths in Europe, ranking third in the world. Rare earths mainly come from apatite deposits in kola peninsula, Chevchenko deposits in Kazakstan and Kurechian deposits. The output of rare earth in Australia, India and Malaysia comes from monazite in coastal sand mines, of which Australia accounts for more than 1/3 of the total output of monazite in the world. Xenotime is the main source of yttrium, a by-product of tin mining in Australia, Malaysia and China, and a part of it is extracted from uranium-bearing leaching residue in Denison of Elliot Lake. The world rare earth industry is developing from producing primary products such as rare earth concentrate and mixed rare earth to producing high-purity and single rare earth deep-processing products.
There are many kinds of rare earth deposits, which can be divided into endogenous, exogenous and metamorphic deposits according to their genesis, and then into six types according to the differences of intrusive rocks and mineralization related to the deposits:
(1) Rare earth deposits related to alkaline rocks and carbonate rocks. Most of the world's rare earth reserves are produced from such deposits. At present, the Pass Mountain deposit in California and the Bayan Obo deposit in Inner Mongolia, China have the greatest economic significance. The proven reserve of REO in Shanshan deposit is about 500× 104t, with an average grade of 7%, which is the highest grade carbonate rock in the world. The unique feature of this carbonate is the lack of Ti-Nb minerals. Baiyunebo deposit is a large-scale iron ore deposit rich in rare earth, and rare earth minerals can be recovered as by-products of iron ore mining. The rare earth reserves in this mining area are huge. In addition, Kalonge deposit in Burundi and Kangankunde deposit in Malawi belong to this type.
(2) Alkaline granite pegmatite rare earth deposit. These deposits are widely distributed, but few of them have economic significance. The Guaihu deposit in Quebec, Canada, is a large-scale rare earth-rare metal complex deposit and a potential source of rare earth elements (yttrium and heavy rare earth). Similar deposits have been found in kola peninsula in the former Soviet Union and Colorado in the United States.
(3) Non-carbonate hydrothermal vein rare earth deposits. In addition to rare earth minerals, thorium is also abundant in the deposit. The most typical example is Steenkamp Sclar deposit in Cape Province, which is the earliest monazite deposit found abroad.
(4) Rare earth apatite deposit. Apatite in phosphate rock is often rich in rare earth elements, which can be recovered in phosphate fertilizer production. Although these deposits are widely distributed, there are few large deposits with high rare earth grade, such as rare earth apatite deposits in Xibin alkaline complex in kola peninsula, the former Soviet Union. Apatite in the carbonate deposit in Xilinjave, Finland and the apatite in Kiruna iron deposit in northern Sweden are potential rare earth-containing apatite resources. Zijin, Guizhou, China is a phosphorite deposit containing rare earth.
(5) Weathered crust type rare earth deposits. This kind of deposit is formed by weathering of primary deposits rich in rare earth elements, which has important economic significance. Typical deposits are Alasha alkaline complex in Brazil and granite weathering crust deposit in southern China. The highest rare earth content of the former is about 6%, and the laterite is rich in rare earth elements, which is 5 ~ 15 times that of the upper alkaline rocks. The latter is also called ion adsorption rare earth deposit.
(6) Sediment deposition. Monazite in modern and ancient placers used to be the main source of rare earth oxides, but now it only occupies a secondary position. Rare earth oxides in Australia, Brazil, India and Malaysia mainly come from monazite sand deposits. Australia's monazite sand deposit ranks first in the world in output.
The oversize Olympic Dam copper-uranium deposit discovered in southern Australia in 1980s is a huge potential source of rare earth elements. In recent years, special rare earth mineralization has been discovered in a Cenozoic depression in the coastal area of the former Soviet Union. There are also reports of high rare earth minerals in Carboniferous bauxite deposits in Shanxi, China, but no deposits with industrial value have been found.