Rhenium (lái), which is a relatively uncommon word, is also a metal element that is not familiar to the public, and is rarely heard in daily life. However, its role in aircraft engine manufacturing cannot be underestimated.
Ding Shiqi, deputy to the National People's Congress and deputy general manager of Anhui Tongling Nonferrous Metals Group Holding Co., Ltd., submitted to the third session of the 13th National People's Congress the proposal on implementing the national collection and storage of rare rare and scattered metal rhenium and controlling important strategic resources, which pushed rhenium into the public's view.
"With the development of China's aviation industry, the level of aircraft engine manufacturing and the increase in production, the manufacturing process needs to add some specific metal elements to achieve special properties of the material. However, due to the development of China's aero engine industry has just started, some of the domestic rare and scattered metals such as rhenium metal demand is small, the development of the industry is constrained." Ding Shiqi said.
As a representative of the National People's Congress in the mining industry, Ding Shiqi will of course devote more effort to special rare metals than others, and the field of concern is of course relatively unique. He hopes that everyone will pay more attention to the strategic role of rhenium in the development of the country's aviation industry. Ding Shiqi called for the urgent need to control important strategic resources through national procurement and storage, protect the self-sufficiency of key materials, and ensure the safe supply of key materials for major national equipment.
Rare and Application of Rhenium
Rhenium is an extremely rare metal element on the earth, and its abundance in the earth's crust is very low. It does not form or rarely forms independent minerals in the evolution process of the earth, but exists in other minerals in a similar way, which is a typical rare element.
China began to extract rhenium from molybdenum concentrate roasting dust in the 1960 s.
Rhenium is mainly associated with molybdenum and copper mines. According to the report of the United States Geological Survey, the world's proven rhenium metal mineral resources are about 2453 tons, and the global basic total reserves are about 10180 tons. The countries with abundant resources are: Chile 1300 tons, the United States 390 tons, Russia 310 tons, Kazakhstan 190 tons (quoted from "Metal Encyclopedia"). At present, about 2/3 of the world's rhenium is produced by Chile (the actual controller is the financial capital of the United States, such as Morgan), and other producing countries include the United States, Poland, Kazakhstan and China.
Rhenium has excellent physical and chemical properties and is irreplaceable in some applications. Rhenium is one of the most refractory metals, with a melting point of up to 3180°C. It has high mechanical strength, good plasticity and excellent mechanical stability. Metal rhenium has no brittle critical transition temperature, and has good creep resistance under high temperature and rapid cooling and rapid heating conditions, which is suitable for ultra-high temperature and strong thermal shock working environment. Rhenium is widely used in aerospace special alloys, using rhenium to produce high-performance single crystal high-temperature alloys, which are used in aero-engine blades.
At present, the application of rhenium in the aero-engine industry has reached more than 80% of the total amount of rhenium. The application of rhenium in single crystal alloys is increasing with the replacement of single crystal blades. From the second generation of single crystal alloy began to use rhenium, such as Russian ЖС 36, using 2% rhenium, the United States CMSX-4 used 3% rhenium; The third generation single crystal alloy, represented by ReneN6 and CMSX-10 in the United States, has a maximum rhenium content of 5.6 and 7% respectively. The fourth generation single crystal alloy is represented by Japanese TMS-138 and MC-NG, the two contain 5% rhenium and 4% rhenium respectively. The fifth generation single crystal alloy, represented by TMS-162 in Japan, contains 6% rhenium (quoted from "Metal Encyclopedia" and "Science Popularization and Culture of Land and Resources"). At the same time, as the global civil aviation market expands and low-cost airlines continue to expand around the world, the number of civil aviation engines will continue to grow. Demand for military aero engines and rocket engines has surged due to global regional tensions. According to industry forecasts in the next 10 years, the global demand for rhenium resources has more than doubled growth.
In addition, rhenium and its compounds also have excellent catalytic activity, used in petroleum reforming catalyst, the demand growth is also fast.
Major countries are competing for rhenium resources
Rhenium is a scarce strategic material, and the demand for rhenium is increasing in major countries. Based on this international market consumption reality, Ding Shiqi's anxiety is not without reason.
Rhenium major consumer countries are the United States, the European Union, Japan, Russia and so on. In recent years, the annual consumption of rhenium in various countries has increased year by year. Among them, the annual consumption in Europe has increased from 2-3 tons to nearly 10 tons, the annual consumption in the United States has increased from 20-25 tons to 45-50 tons, the consumption in Japan has increased to about 2-3 tons/year, and the annual demand in Russia is about 5 tons (quoted from the 2014-2018 Rhenium Industry Research Report of China Research Institute and Puhua and the United States Geological Survey-Mineral Survey 2019).
At present, the major countries take measures to occupy rhenium resources. Molybdenum Metals is the world's largest rhenium producer. It monopolizes most of the rhenium production in Chile, Mexico and Kazakhstan in the form of long-term contracts. The United States reserves all domestic products and a significant portion of imports. In May 2018, the U.S. Department of the Interior released the final list of "35 key minerals", believing that these mineral products are vital to the national security and economic prosperity of the United States, and measures will be taken to enhance the security capability.
Rhenium metal resources are very scarce in China. China's rhenium resources reserves are very small, and even there is no clear statistical data. Ore resources containing metal rhenium and its associated resources are unique. Some data show that the resources of rhenium in China are only 237 tons, and almost most of them come from the accompanying of imported overseas copper and other metal ores.
China's metal rhenium production capacity is small, the output is very low. According to reports, the actual domestic rhenium metal production capacity of about 8 tons/year. However, the current demand for rhenium in the domestic aviation industry is growing slowly, and most of them are only required by individual R & D companies.
"In recent years, China's consumption of rhenium has stabilized at around 2 tons, and with the rapid development of the domestic aviation industry, the demand for rhenium will continue to increase. A substantial breakthrough in the development and manufacture of a new generation of aero engines in the future will result in a significant increase in the demand for metal rhenium." Ding Shiqi said that in addition, the rhenium platinum alloy containing 30% rhenium is an important catalyst in the catalytic reforming process, which can greatly increase the octane number of naphtha, and the demand for rhenium has maintained a certain growth.
"Through the treatment of copper and molybdenum metal smelting enterprises polluted acid or soot, concentrated and purified to make ammonium rhenate, can be refined into metal rhenium." Ding Shiqi said that Tongling Nonferrous Metals Group is the largest copper smelting enterprise in the world, importing more than 3 million tons of rhenium-containing copper concentrate from overseas every year, including 5-8 tons of rhenium resources. In 2018, Tongling Nonferrous joint venture to build an annual output of 5 tons of metal rhenium project, has been successfully put into production, the output of qualified high-purity metal rhenium.
It is recommended to carry out the national collection and storage of rhenium metal.
"However, with the commissioning of China's metal rhenium project, overseas metal rhenium manufacturers have also begun to dump at low prices, causing the price of rhenium to continue to fall, and it has now fallen to the 1/3 of the market price three years ago." Ding Shiqi said that the operating rate of the production lines of many copper-molybdenum smelting enterprises to recover rhenium resources (mainly ammonium rhenate, an intermediate product of rhenium metal) is extremely low, and the units are started and stopped, which seriously dampens the enthusiasm of rhenium production enterprises. Most of the precious rhenium resources are disposed of at will with waste residue, resulting in great waste.
"Due to the current slow development of the domestic aero-engine industry, the total demand for rhenium is not large for the time being, resulting in difficulties in the development of the rhenium metal industry. However, due to the scarcity and extreme dispersion of rhenium metal global resources, it is very difficult to increase its supply in the short term." Ding Shiqi said that at present, the state has come forward to purchase and store metal rhenium products, which will play a positive role in boosting the confidence of rhenium production enterprises, ensuring the recovery of associated rhenium resources by copper and molybdenum metal smelting enterprises, and improving the comprehensive utilization of resources.
To this end, Ding Shiqi put forward three major proposals:
1. comprehensive development of rhenium metal national storage. High-purity rhenium metal will be included in the national reserve catalog, and a comprehensive national collection and storage work will be carried out immediately. As a scarce rare and scattered metal, to prevent other countries to China's import control, to carry out a comprehensive collection and storage of strategic materials, can ensure the safe development of China's aerospace.
The 2. proposes to reduce or exempt rhenium metal manufacturing process value-added tax, income tax and other preferential policies to encourage enterprises to improve the recycling of rhenium resources. It is recommended to formulate preferential policies such as value-added tax and income tax reduction and exemption in the manufacturing process of rhenium metal, actively encourage copper-molybdenum metal smelting enterprises to actively recover ammonium rhenate, an intermediate product of rhenium metal, and encourage enterprises to increase the comprehensive utilization of resources, so as to provide key resource protection for the national security strategy.
3. reduction of rhenium metal import duties and value-added tax, encourage the collection of foreign rhenium resources. At present, rhenium metal imports are still subject to 3% or 20% customs duties and 13% value-added tax. For scarce strategic resources, it is recommended to implement a tax reduction and exemption strategy to encourage priority access to and use of other countries' resources for our strategy.
Website Editor: Gong Li
