Magnesium aluminate spinel preparation

Preparation and Characterization of Magnesium Aluminate Spinel for SOx Abatement in Fluid Catalytic Cracking... 

Recent studies have demonstrated that cerium containing magnesium aluminate spinels such as MgAl204 and Mg2Al205 are very effective SOx reduction catalysts for FCC units. These magnesium aluminate spinels can be prepared by three different techniques (i) thermal co-condensation... 

Designing a catalyst for effective removal of SOx (S02 + S03) in a fluid catalyst cracking unit regenerator is a challenging problem. One must come up with a particle having physical properties similar to FCC catalysts which will 1) oxidize S02 to S03, 2) chemisorb the S03/ and 3) be able to release it as H2S as it enters the reactor side of the unit. A cerium containing magnesium aluminate spinel was found to be very effective for this purpose (1). The preparation methods and characterization techniques utilized for this spinel catalyst and how the SOx abatement activity of this catalyst is related to the preparative route used are discussed in this paper. 

Magnesium aluminate spinels can be prepared(5-8) by various methods such as i) thermal co-condensation of oxides, ii) co-precipitation of hydroxides, and iii) co-gel formation. The results obtained from each of these procedures are briefly discussed below. 

Li JG, Ikegami T, Lee JH, Mori T, Yajima Y (2001) A wet-chemical process yielding reactive magnesium aluminate spinel (MgAl204) powder. Ceram Int 27 481 89 Sun YF, Lu TC, Wang XJ (2007) Preparation and optical properties of transparent Mn MgAl204 ceramics. Rare Metal Mater Eng 36 438-441... 

Wang, Y., Zhang, F., Xu, S., Yang, L., Li, D., Evans, D. G., and Duan, X. Preparation of macrospherical magnesia-rich magnesium aluminate spinel catalysts for methano-lysis of soybean oil. Chem Eng Sci 63,4306-4312 (2008). 

Active phases are made of Rh dispersed on a magnesium aluminate spinel support. Two preparation techniques are reported here. 

Evidence of spinel structure was determined in the reaction bed by x-ray powder diffraction. The mineral spinel, magnesium aluminate, possessed unusual catalytic activity. Artificial spinels, prepared from other elements but still having the basic spinel structure, also were found to be active catalysts. 

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