Basic properties and industrial chain of cesium rubidium
Cesium, element symbol Cs, atomic number 55, density 1.88g/cm ³， The melting point is 28.4 ℃, and the boiling point is 678.4 ℃. The metal cesium is light golden yellow, very soft and ductile.
The chemical properties of cesium are extremely active. The compounds mainly include cesium carbonate, cesium formate, cesium bromide, cesium chloride, cesium fluoride, cesium iodide, cesium hydroxide, cesium nitrate, cesium oxide, cesium sulfate, cesium alum, etc.
In terms of downstream applications, as a rare mineral, cesium metal and cesium salt are irreplaceable in many industries. At present, they are mainly used in atomic clocks, energy, chemical, medical and other fields.
Rubidium, element symbol Rb, atomic number 37, density 1.53g/cm3, melting point 38.89 ℃, boiling point 688 ℃. Rubidium metal is silver white wax, soft and light, and ductile.
The rubidium compounds used in industry mainly include rubidium oxide (Rb2O, RbO2, Rb2O2, etc.), rubidium hydroxide, rubidium carbonate, rubidium sulfate, rubidium nitrate, etc.
Because rubidium and cesium have similar physical properties and atomic radii, their downstream applications are similar and can be used interchangeably in many applications.
But because cesium is more positive than rubidium, and rubidium has no independent deposit, it is usually a by-product of lithium and cesium production, and is not easier to obtain than cesium, making cesium more widely used than rubidium.
The global cesium resources are scarce and highly concentrated
Cesium has no elemental form in nature. It is mainly distributed in the land and sea in the form of salt, and the global mineral reserve is rare.
Cesium has an independent mineral cesium garnet, and the content of Cs2O is 5%~32%. It is the main raw material for extracting cesium.
According to USGS data, the global reserves of pegmatite type cesium mineral resources in 2020 will be 217100 tons, including 120000 tons in Canada, 60000 tons in Zimbabwe, 30000 tons in Namibia and 7100 tons in Australia.
The global cesium mineral resources are very scarce. At present, the cesium garnet resources that can be exploited in a large scale are mainly concentrated in three mining areas:
Tanco mining area in Canada, Bikita mining area in Zimbabwe and Sinclair mining area in Australia.
Since the Tanco mine collapsed from 2010 to 2013, and then was suspended from operation, and the subsidence area was repaired from 2017 to 2018, USGS did not count the retained cesium resources in the Tanco mine area from 2016 to 2019.
In June 2019, China Mining Resources Group Co., Ltd. acquired 100% of the Special Fluid Business Unit of American CABOT Company and its Tanco mine. In 2020, USGS added the data of retained pegmatite cesium garnet type cesium resources in Canada, and the newly increased retained 120000 tons of cesium oxide resources in Canada were all from Tanco mines.
Rubidium resources have no independent minerals and are mainly by-products of lithium and cesium
More than 90% of the total reserves of rubidium resources exist in salt lakes, but they are usually at a trace concentration (about 0-20mg/L), with limited development and utilization value.
At present, most rubidium is extracted from granite pegmatite, and the carrier minerals are mainly lepidolite, lepidolite, cesium garnet and K-feldspar.
Although rubidium is more abundant than lithium and cesium in the earth, it is difficult to extract because there are no rubidium rich minerals, and it is mainly produced as a by-product of cesium and lithium processing.
The global rubidium resources are mainly concentrated in Namibia, Zimbabwe and Canada.
According to USGS data, the global rubidium resource reserves in 2020 will be 102000 tons, including 50000 tons in Namibia, 30000 tons in Zimbabwe, 12000 tons in Canada, and 10000 tons in other countries, with high resource concentration.
The global consumption of rubidium is small, and it has remained at 10-12 tons in recent years.
The United States is the first country in the world to produce and apply rubidium. In 2018, rubidium will be included in the list of 35 key minerals. The application of rubidium in the United States is 80% for the development of high-tech, 20% for special glass, catalyst and other fields, and the annual consumption is 5-6 tons.
Japan is the country with the fastest development of rubidium production and application in the world in the past 20 years. In July 2009, Japan issued the Rare Metals Guarantee Strategy, which regards rubidium as a strategic mineral. Its fastest development of rubidium application is in the field of catalysts, especially organic synthesis catalysts. At present, the annual rubidium consumption is 1-2 tons.
China has no independently exploitable cesium rubidium resources
The domestic production of rubidium and cesium resources mainly focuses on the development of solid minerals. Rubidium mainly exists in the form of associated minerals, mainly from lepidolite. The cesium resources are mainly distributed in Altai region of Xinjiang and Yichun of Jiangxi.
Among them, the early developed Keketuohai mining area in Xinjiang has cesium garnet concentrate containing about 18% - 25% Cs2O, and lepidolite containing 0.9% Rb2O, which is an important rubidium cesium producing area in China.
Since the closure of Koktohai No.3 Mine, there has been no independent cesium garnet mine available for mining in China. At present, cesium raw materials needed in China are mainly imported from abroad.
The accumulated hard rock type retained cesium resources detected in major mining areas in China totaled 61800 tons, but most of them were difficult to deal with cesium resources associated with lithium mica, which had no value for independent development and utilization. Generally, only cesium rubidium and other associated minerals were extracted from tailings after lithium extraction from lithium mica.
Under the current technical and economic conditions, the associated rubidium and cesium resources in brine of salt lakes do not have the value of independent development and utilization.
At present, the cesium resources that are feasible and available for economic development and utilization come from cesium garnet type cesium mineral resources that occur in pegmatites.
At present, China's Rb2O reserves are about 184000 tons, and the basic reserves are about 311000 tons.
It is found that the resource amount is about 1.958 million tons, of which the hard rock type Rb2O is about 1.904 million tons, accounting for 97% of the national Rb2O resource amount.
According to the occurrence state of rubidium in China, rubidium ore can be divided into mica type rubidium ore resources hosted in mica and feldspar type rubidium ore resources hosted in feldspar.
Lepidolite and iron lepidolite are widely distributed in Jiangxi, Hunan and Henan; Feldspar is mainly distributed in Xinjiang and Shanxi provinces; Cesium garnet is mainly distributed in Xinjiang, Sichuan, Yunnan, Jiangxi and Hunan provinces.
Environmental protection and emerging science and technology are the core driving force for cesium and rubidium consumption
The largest application field of cesium rubidium is oil and gas drilling. As a drilling/completion fluid, cesium formate has the advantages of high temperature resistance, high efficiency, and environmental friendliness in the process of oil and gas drilling under high temperature and pressure. Due to the high price, its current application is mainly concentrated in Europe, In the future, the demand for cesium formate in China's oil and gas drilling field will become a huge growth point for cesium rubidium demand.
In addition to oil and gas drilling, the most widely used use is catalyst. The use of cesium sulfate as a catalyst in the production of sulfuric acid can significantly reduce SO2 emissions, thereby reducing the cost of subsequent tail gas treatment. With the increase of sulfuric acid production in China and the increasingly strict requirements on environmental protection, cesium sulfate has a broad market prospect in the future.
In addition, with the arrival of the 5G era and the national emphasis on scientific and technological development, high-tech fields such as atomic clocks, magnetohydrodynamic generators, and ion thrusters will also become the growth points of cesium rubidium demand.
Due to the scarcity of cesium garnet resources and high industrial technical barriers, only Dongpeng New Material, Cabot and Yabao can realize the mass production of cesium rubidium salts worldwide.
Since there is no independent ore, the average price of rubidium products is 5-6 times that of cesium products, and their main application fields are similar, the competitiveness of cesium products is much higher than that of rubidium products.
Due to the high technical barriers in the rubidium cesium salt market and the high concentration of suppliers, the suppliers have strong bargaining power, and the prices of the main cesium salt products will be stable and progressive in 2020.
Three major cesium garnet mines in the world
Tanco Mine, Canada
Equity structure:
The mining right of Tanco Mine belongs to Tanco, a Canadian tantalum company (Tanco for short), and China Mineral Resources holds 100% of the shares of Tanco.
Mine introduction:
Tanco mine is located 160 kilometers northeast of Winnipeg City, Manitoba, Canada, on the northwest bank of Lake Bernick. It is a typical lithium cesium tantalum (LCT) type pegmatite deposit, rich in lithium, cesium, rubidium, tantalum, beryllium, gallium and other rare metal elements. Tanco mine is the largest cesium garnet mine discovered at present, with 80% of the global cesium garnet resource reserves, and the average grade of cesium oxide is 23.3%.
Tanco mine has 117200 tons of untapped cesium ore resources, including 16200 tons of cesium oxide; The resource amount of cesium tailings ore is about 3.5222 million tons, of which the content of cesium oxide is about 26000 tons, and the total amount of cesium oxide resource of Tanco mine is 42200 tons.
Mine history:
From 2010 to 2013, the No. 14 pillar in Tanco mining area experienced two roof falls, and the mine was suspended.
From August 2017 to July 2018, Cabot completed the restoration of the collapsed area under the supervision of the Canadian Geological and Mining Review Board (GMRB), and then continued mining.
In 2019, China Mining Resources acquired Cabot Special Fluid Business Unit, thus realizing 100% holding of Tanco Mine.
Bikita Mine in Zimbabwe
Equity structure:
African Minerals holds 55.4% shares and Mavhaire holds 16% shares
Mine introduction:
Bikita Mine in Zimbabwe is a world famous lithium cesium tantalum (LCT) multi rare metal mine, and also one of the main mines for mining cesium garnet in the world.
Since it was discovered in 1911, it has produced a large number of lithium, cesium, tantalum and other minerals. The ore bearing pegmatite is about 3 kilometers long and 150-180 meters wide. A total of 2.6 million tons of lithium permeable feldspar (Li2O 4.13%) have been detected, including 3.73% rubidium in lepidolite, 2 million tons of spodumene (Li2O 1.7%), and 100000 to 150000 tons of cesium garnet (Cs2O 24%). The pegmatite also shows strong zoning characteristics.
However, after decades of development, its cesium garnet type ore resources are basically exhausted.
Sinclair Mine, Australia
Equity structure: Pioneer holds 100% of the shares.
The Sinclair mine is located 35km north of Northman, Western Australia. It was discovered by Pioneer Resources Co., Ltd. in 2016. It is the first cesium garnet deposit found in Australia, and is one of the three largest cesium garnet deposits that can be large-scale mined in the world after Tanco Mine and Bikita Mine.
From 2016 to 2019, the first stage of mining operation of Sinclair Mine has been completed.
In the first stage of mining exploration, when the cesium garnet ore in the polymetallic deposit has not been reached, 7110 tons of ore resources, 16.4% cesium oxide grade and 1166 tons of cesium oxide have been obtained.
At present, the second stage of mining and exploration is under way in Sinclair Mine.
Phase I:
Pioneer found cesium garnet in a prospecting activity from August to October 2016, started mining in September 2018, and completed the first stage of mining exploration in January 2019. The mine resources and sales in this stage are shown in the table below.
The cash operating surplus in the first stage was US $10.2 million, that is, the average profit of cesium oxide was US $6576/ton, or the average profit of ore (cesium oxide grade 8.3%) was US $547/ton.
The stripping ratio of cesium garnet ore in the first stage is close to 70:1. After the completion of the first stage of mining, Sinclair Mine proved to have the potential to carry out the second stage of mining.
Phase II:
In the first stage of exploration, cesium garnet resources were found at least 80 meters away from the north of the mine pit. Therefore, Pioneer has formulated the second stage of exploration objectives, that is, to obtain ore resources with a cesium oxide grade of 8%~14% of 1000~2000 tons.
Cesium rubidium application: mainly oil and gas drilling, opening new demand in the scientific and technological field
Oil and gas drilling
Cesium formate is the only cesium salt that can be industrially produced in the world, and also the product with the highest proportion of demand in the downstream of cesium salt in the world. It is mainly used as oil completion fluid to prevent drill bit dissolution in deep well exploitation.
In 1922, cesium formate was developed and left unused for more than 70 years. Until 1995, Europeans studied the application of cesium formate in offshore deep well drilling and tested it in the North Sea oilfield.
In 1999, Shell used cesium formate brine as a perforating fluid in Shearwater Oilfield, and in 2001, cesium formate was used as a drilling fluid in Huldra Gas Field, opening the way for the application of cesium formate in oil and gas drilling.
In the past decade, cesium formate solution has been successfully used in more than 100 wells as drilling fluid, completion fluid, workover fluid and suspension.
Compared with traditional solid drilling fluid, cesium formate has obvious advantages:
1) The solid containing drilling fluid is subject to bentonite cementation under the influence of high temperature, which is easy to form thick filter cake, while solid free high-density drilling and completion fluids such as cesium formate will not;
2) The performance of additives can be maintained at high temperature;
3) The solubility of natural gas is low, so it is easy to find well kick, and well control measures can be implemented in time;
4) The equivalent density is low, the resistance of liquid flow is reduced, the lubrication performance is good, and the failure rate of sticking is reduced;
5) It is biodegradable and has little impact on the environment.
Cesium formate consumption for oil and gas drilling: a deep well needs about 500 tons of cesium formate.
The high price of cesium restricts the application of cesium formate drilling and completion fluids. In order to maximize the economic benefits of cesium formate drilling and completion fluids, cesium formate needs to be recycled.
The recovery of cesium formate drilling fluid can be divided into five steps: screening, centrifugation, chemical treatment, gravity sedimentation and storage. The recovery and reuse rate of cesium formate drilling fluid and completion fluid can reach 80%, and the performance of the recovered base fluid will not change.
Because of the cost and process, cesium formate is seldom used in domestic oil and gas field.
In the field of ultra-high temperature and high pressure drilling and completion, as China's exploration field moves towards deep water and deep layers, the ultra-high temperature and high pressure environment may become the normal state faced by deep oil and gas exploration and development in the future. There are no laws and regulations to avoid such geological conditions as temperature above 200 ℃, pressure coefficient above 2.30, narrow safety window, etc.
In addition, with the increasing attention paid to the environment in China, the implementation of environmental protection policies is gradually strengthened, and the application of cesium formate in the domestic oil and gas field will gradually expand.
In October 2021, CNOOC Research Institute Co., Ltd. released the technical feasibility assessment and key technology research report on the ultra-high temperature and high pressure gas field in Yingqiong Basin, South China Sea, and proposed the use of cesium formate completion fluid, indicating that China's oil and gas companies will also gradually expand the application of cesium formate.
catalyzer
Most of the cesium salts in China and Japan are used as catalysts. The amount used in the catalyst field in Japan has reached 90%, while the organic synthesis catalyst is the main growth point in recent years. A part of the products produced in China are also exported to Japan.
In the cesium salt, cesium sulfate is used as the cesium alum catalyst, and cesium sulfate is also used as the catalyst in the production of ethylene oxide; Cesium nitrate is used as a cocatalyst in petrochemical industry and in the production of methacrylic resin; Cesium fluoride can be used as catalyst for fluorine containing resin and welding flux; Cesium chloride can be used as pharmaceutical catalyst and raw material for preparing metal cesium.
Cesium sulfate is the most promising cesium salt catalyst, which can be used in industrial sulfuric acid production.
At present, vanadium catalyst is widely used in domestic sulfuric acid industry |
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