Uranium, as an energy source for nuclear fuel, is increasingly used in nuclear power plants and marine transportation. It is an important national defense strategic material and an important nuclear fuel.
At present, 16 countries in the world have a nuclear power generation share of nearly 25% of their total national power generation, France and Lithuania have the highest proportion of nuclear power (more than 70%), followed by Russia, the United States, Ukraine, Sweden, South Korea and Japan (both greater than 25%), the world average of 15%, while China's current power supply only accounts for 2.2% of nuclear power. With the development of China's national economy, the state has put forward the basic policy of "actively promoting the construction of nuclear power." According to China's Medium- and Long-Term Development Plan for Nuclear Power (2005-2020), by 2020, more than 30 nuclear power plants will be built in coastal provinces and cities with high population density and high industrialization level, and the installed nuclear power capacity will reach 40GW; On the basis of the current construction and operation of nuclear power capacity of 16.968GW, the newly installed nuclear power installed capacity will reach 23GW; meanwhile, considering the follow-up development of nuclear power, the nuclear power capacity under construction at the end of 2020 should be maintained at around 18GW; nuclear power will account for the total installed capacity of the country. 4%, the proportion of nuclear power generation to total power generation will rise to 6%. As far as the current uranium fuel required by nuclear power plants is concerned, a million-kilowatt-scale PWR nuclear power unit needs 25 to 30 tons of uranium fuel per year, and consumes 150 to 180 tons of uranium. According to the installed capacity of nuclear power in 2009, the demand for natural uranium in China is 1300-1600t/a. If China's nuclear power installed capacity reaches 40GW in 2020, the natural uranium demand will be 6000~7200t/a, and its external dependence will exceed 60%.
With the development of the nuclear industry, high-grade uranium mines are increasingly depleted, resulting in the accumulation of low-grade ore and tailings. However, when mining these low-grade uranium mines, the traditional methods have disadvantages such as high cost, low efficiency, and large environmental pollution. The biological metallurgy, mineral exploitation as an emerging technology, has a "green metallurgy" in the world, and has been successfully used low-grade refractory ore to depleted uranium leaching and heap leaching.
2 Â Â Microbial leaching uranium technology and its mechanism
The use of leaching microorganisms (bacteria, fungi, archaea) to oxidize sulfide ore in the surrounding rock of uranium ore to produce oxidants (Fe 3 + , H + , etc.) that dissolve uranium or to regenerate Fe 2+ in the leachate The purpose of dissolving uranium ore is to effectively treat low grade and refractory uranium ore.
In most of the uranium ore which, more or less, there are some metal sulfide ore, more common pyrite. A uranium mine containing very low sulphide ore can add appropriate Fe 2+ as a source of microbial energy in the leaching solution. The mechanism is mainly indirect action in biometallurgy, that is, uranium ore is mainly dissolved under the action of oxidant Fe 3+ and H + , and the role of microorganisms is to regenerate oxidant Fe 3 + and/or to be in surrounding rock. The elemental sulfur and other reducing sulfur compounds produced by the dissolution of the sulfide ore are oxidized to sulfuric acid to maintain the acidic oxidizing environment required for the dissolution of the uranium ore.
This dissolution process is usually expressed by the following reaction formula: 
The above is the basic biochemical reaction of the microbial uranium process, but in the actual production process, in addition to the initial addition of the bacterial leach solution, the bacterial leachate needs to be replenished and regenerated during the leaching process, which is critical to the entire leaching system. Importantly, the supplemental regeneration process of bacterial leachate is very similar to bacterial culture. In the process of replenishing and replenishing the leachate, the microbial community structure and the content of iron and other impurity ions in the leach solution can be appropriately controlled, thereby ensuring a favorable microbial immersion uranium system.
The baby grows up day by day, and likes swimming every day. In order to continue the project of baby swimming, the baby's head can also be raised at that time, and he no longer likes to be strangled by the neck. The baby also needs a wider field of vision. The depth of the baby swimming pool cannot reach the purpose of the baby's swimming (the baby's feet touch the bottom of the pool). If you want to swim in the original baby swimming pool, you must increase the baby's swimming height or increase the depth of the pool. The neck is moved to the base of the thigh, which increases the height of the baby's swimming. In order to solve these two problems, the Inflatable Baby Swim Seat was created.
The Inflatable Baby Swim Seat has multiple independent airbags, and there is an anti-leakage device in the air nozzle, which is safe and reliable. The swimming ring is carefully designed, made and comfortable to wear according to the characteristics of the baby's thigh. Proper use can prolong the use time.
Inflatable Baby Swim Seat,Baby Swimming Pool Floats,Baby Pool Floats,Infant Pool Float With Canopy
P&D Plastic Manufacture Co., Ltd , https://www.jmpoolfloat.com