was discovered in the year 1789 by a German chemist named MartinHeinrich Klaproth in its natural oxide state from the mineralpitchblende. He named the uranium after planet Uranus. AlthoughKlaproth together with other scientists thought that what he haddiscovered was pure uranium, they were wrong. It was uranium dioxide(UO2).The first person to isolate it was Eugene Peligot in the year 1841.In 1896, was also discovered to be a radioactive element byHenri Becquerel, a French physicist (Emsley, 476).
is a shiny and silvery metal which is malleable and ductile. Itsmelting point is 1135 degrees Celsius or 1408K and the boiling pointis 4131 degrees Celsius or 4404k. Its density is 18.95g/cm3.Inthe periodic table, uranium belongs to period seven and a group ofmetals known as actinide. Its atomic number is 92 and symbol is U.its atomic weight is 238.03g/mol. The chemical properties of uraniuminclude, reacting with water if it is finely pounded, reacting withoxygen in the air to form a uranium oxide coat. also reactswith acids and steam. It reacts with other metals to form intermetallic compounds and solid solutions (Emsley, 476).
is naturally found in small amounts in nearly all rocks, seawater andeven in soil. In its natural state, uranium is not pure. It is foundin large quantities of carnotite (K2(UO2)2VO4.1-3H2O),uraninite (UO2)and pitchblende as well as autunite (Ca(UO2)2(PO4)2.10H2O).These are basically mixtures of uranium oxides (Emsley, 476).
Naturaluranium basically consists of three isotopes which includeuranium-235, uranium-238, and little quantities of uranuim-234.However, there are three other artificial isotopes produced throughthorium and uranium-235 reactors. All the three artificial and threenatural isotopes emit alpha particles. All the three isotopes ofnatural uranium are radioactive, that is, they form radioisotopes.The most stable and abundant radioisotope of uranium is uranium-238which has a half-life of 4.4 billion years, almost the earths age.This is followed by uranium-235 whose half-life is 700 million years,and finally is uranium-234 with a half life of 240,000 years.-235 is used commercially to produce nuclear power.-238 can also be transformed into uranium-239 which is used infueling nuclear reactors (Morss et al 231).
Afteruranium ore is mined from the underground rocks and soil where itoccurs naturally, the process that follows is uranium extraction. Theprocess of uranium extraction involves heating the raw uranium ore togrind and roast it. The purpose of heating is to burn anycarbonaceous species in the raw ore and make it more reactive duringthe leaching process used to produce pure uranium. At times, the rawore is heated together with some salts so as to enhance thesolubility of metals impurity in the solution used to leach it. Theleaching process can either be done using alkaline or acid solution.However the most effective solution for leaching is acid solutionbecause it is most effectual with the difficult ores. Sulfuric acidis the most commonly used acid because of solubility of the uranylsulfate complexes. Once put in the acid, it undergoes a set ofreactions until the preferred complex [UO2(SO4)3]4is obtain. is then recovered from this solution. Althoughsulfuric acid is the preferred leaching agent, other acids such ashydrochloric and nitric acid can be used also, but they are verycorrosive and expensive. On the other hand, the use of alkalineleaching agents depends on the formation of uranyl tricabonate[UO2(CO3)3]4 from where uranium is recovered. The preferred alkaline leachingagents are sodium carbonate and sodium bicarbonate because theyprevent compounds of uranyl hydroxide from forming. Since alkalinesolutions react slowly, the process is accelerated using increasedtemperatures and pressures. Another modern method of purifying rawuranium ores called in-situ uranium leaching has been invented. Thisprocess is similar to that of acid or alkaline leaching, only thatthe solution used to leach the raw uranium ore is pumped while in theground still. However, this modern method has raised concerns overcontamination of ground water and the soil in the mining sites (Morsset al, 231).
Oneof the uranium’s large scale uses is in the production of nuclearenergy from its natural isotope uranium-235. Its isotope uranium-238is also used in fueling nuclear energy plants. It is also used inhospitals as an X-ray production target. It also used by the militaryas ammunition for certain kinds of their weaponry such as missilesand bullets, and in protection against radiation. is alsoused in airplanes and helicopters in some part of the wings ascounter weights as well as in the gyroscopes of the system ofinertial guidance. It is also used in manufacturing phosphatefertilizers. One negative use of uranium is in the manufacturing ofatomic bombs known to cause massive destruction of properties andloss if lives. Moreover, compounds of uranium have been used to colorglasses for the longest time. trioxide is used in makingfiestaware plates which are yellow in color. They are also used tomanufacture Vaseline glazes and glass. Depleted uranium is also usedin electricity production (Harry, 20).
Exposureof human beings to uranium cause both radiological and chemicaltoxicity. There are various likely health effects related to humanexposure to uranium radiation. Since all the uranium isotopes emitalpha particles which have ability to penetrate human bodies, themajor radiation risk from uranium metal takes place when compounds ofuranium are either inhaled or ingested. For people who work inuranium processing and storage facilities, the effect of primaryradiation on their heath is of great concern. This is because of theincreased likelihood of these people developing cancer. Thelikelihood of developing cancer that is induced by uranium radiationincreases with increased exposure to uranium. The major chemicalhealth effect related to uranium exposure is kidney and lungtoxicity. This is caused as a result of breathing air which hasuranium dust or ingesting substances which have uranium or itscompounds. Once in the body, some uranium is removed from the bodythrough urine. However, the uranium which is absorbed in the bloodstream cause kidney cell toxicity as they try to filter the uraniumcompounds. intake that is very high can result to severekidney failure which eventually causes death. Moreover, breathing alot of hair which contains high quantities of uranium dust can causelung toxicity. However, at very low uranium intakes levels, the lungsand kidneys repair themselves over few weeks once uranium exposurehas ended (Craft et al, 297). Due to the risks of exposure toradioactive rays as well as nuclear warfare, uranium may havenegative effects on my life. However, emerging technologies arelikely to solve the problem of exposure and the energy prospects ofuranium and other radioactive isotopes may positively improve life.
Emsley,John. "".Nature`sBuildingBlocks:AnAtoZGuidetotheElements.Oxford: Oxford University Press. (2001).
Morss,Lester R. Edelstein, Norman.M. and Fuger, J. TheChemistryoftheActinideandTransactinideElements.Netherlands: Springer, (2010).
Craft,E. S. Abu-Qare, A. W. Flaherty, M. M. Garofolo, M. C. Rincavage,H. L. and Abou-Donia, M. B. (2004). "Depleted and naturaluranium: chemistry and toxicological effects". JournalofToxicologyandEnvironmentalHealthPartB:CriticalReviews7 (4): (2004). 297–317.
HarryBrearley. TheAnalytical Chemistry of ,General Books LLC, (2013).