ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Rare earth oxides have been widely investigated in catalysis as structured and electronicpromoters to improve the activity and thermal stability of catalysts. Cerium has an important role inthree-way catalysis and fluid catalytic cracking, two significant catalytic processes by theireconomic relevance and tonnage. Cerium and other rare earths have been studied as possibleheterogeneous catalysts at selective oxidation of hydrocarbons. Cerite and monazite are mineralswith high concentration of cerium element. Extraction of cerium metal using conventional leachingprocesses has shown low yields or high costs. The main purpose of this research work is to optimizethe parameters in cerium purification stage from this mineral using leaching process. To separateparticles with different granulometries, the mineral is ground and fractioned with sieves of 80, 200,250 and 400 mesh. In order to put off organic components and oxidize cerium(III) to cerium(IV),samples were roasted at 1073K by twenty-four hours. The roasted samples were solubilized by acidattack (leaching) for approximately twenty-four hours; according to the acid used hydrochloric orsulfuric), cerium and other trivalent elements are solubilized as chloride or sulfate solution. Ceriumwas extracted by selective precipitation at pH~3,4 using ammonium or natrium hydroxide as pHchanger. After filtration and drying, the precipitated product was characterized by XRD (x-raydiffraction), and then process efficiency was determined (cerium percentage and the differentphases in the powder). Particles granulometry, roasting process (time and temperature), as well asleaching parameters (acid used, time, temperature and concentration of reagents) were the mainvariables studied
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/12/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.514-516.1653.pdf
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