• Applied Chemistry for Engineering
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• v.9 no.3
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• pp.407-412
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• 1998

This study was carried out to investigate the optimum leaching conditions for the sulfation and water leaching, and separation of cerium from rare earth elements in leached solution by acid-adjusting method. The optimum conditions for the sulfation and water leaching from bastnasite concentrates are that the equivalent ration of sulfuric acid to concentrates is 2.5, calcination temperature and time are $600^{\circ}C$ and 2 hrs respectively, and the pulp density in the water leaching is 9.1%. The yield of rare earth oxide is about 93% at the above condition. The process of recovery of cerium hydroxide from leached solution by acid-adjusting method was carried out as following steps. The first step is the oxidation of the solution at pH 5 by using twice the equivalent of $H_2O_2$ solution as an oxidant. The second step is the precipitation to obtain cerium complex salt and cerium hydroxide after lowering the solution to pH 2. The last step is the oxidation-precipitation by using equivalent of $H_2O_2$ solution. From these results, it was possible to prepare cerium hydroxide with the yield of 60% and the quality of 80%.

• Resources Recycling
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• v.19 no.6
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• pp.27-35
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• 2010

Rare earth alloys and compounds are the raw materials for the manufacture of advanced materials. Although domestic monazite ores have been found, there are some difficulties in recovering rare earth from these ores. Rare earth ores are found in few countries and these countries put an embargo on the export of rare earth ores for the protection of their industry. We gathered some information on the hydrometallurgical and pyrometallurgical processes to recover rare earths from bastnasite, monazite, and xenotime which consist of 95% of the total rare earth ores. Since rare earth with the purity more than 6N is needed for use in advanced materials, some separation methods such as fractional crystallization, precipitation, ion exchange, and solvent extraction were introduced.

• Resources Recycling
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• v.21 no.3
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• pp.74-83
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• 2012

Rare earth metals have been made from rare earth compounds which were prepared from rare earth ore concentrates through successive processes such as leaching(i.e. extraction of rare earth elements to liquid media), separation, purification, precipitation. Here, process for treating monazite and bastnasite ore concentrates were briefly reviewed, and metallothermic reduction and fused salt electrolysis methods were introduced as the extraction technologies for rare earth metals.

• Asian Journal of Turfgrass Science
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• v.25 no.1
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• pp.89-93
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• 2011

This study was conducted to evaluate the effects of bastnasite nitrate fertilizer (BNF) on the growth of creeping bentgrass. Fertilizer treatments were designed as follows; non-fertilizer (NF), control (CF; compound fertilizer), RE-l (CF+0.3 $g{\cdot}m^{-2}$BNF), RE-2 (CF+0.5 $g{\cdot}m^{-2}$BNF), RE-3 (CF+1.0 $g{\cdot}m^{-2}$BNF) and RE-4 (0.5 $g{\cdot}m^{-2}$BNF). Every treatment was arranged in a randomized complete block design with three replications. In creeping bentgrass, turf qualities such as turf color index and chlorophyll index, shoot number, clipping dry weight and nutrients of tissue were measured. It was hardly affected by BNF application in investigation of chemical properties of the soil. By applying BNF, turf color index and chlorophyll index in RE-2 were increased 3.9% and 9.2% more than NF. As applied BNF on creeping bentgrass, shoot number was increased 9% in RE-4 more than NF and 22% in RE~2 more than CF. It was increased in N uptake and clipping dry weight of creeping bentgrass by supplying BNF. These results indicated that the BNF application promoted a turf qualities and a growth of creeping bentgrass by advancing N uptake and shoot number.