CALCINED, TABULAR, AND ALUMINATE CEMENTS

Nonmineralized SGA flows freely, and is often known as sandy alumina because it easily covers the cryoflte bath of aluminum electrolysis cells (see Aluminum compounds, introduction). Properties typical of a sandy SGA are shown in Table 1. Aluminum smelting technology in the United States is primarily based upon sandy alumina. Older European smelting technology, however, is based upon a poor flowing, low bulk density, highly mineralized SGA called floury alumina, composed principally of a-Al O.  

Kirk-Othmer Encyclopedia of Chemical Technology (4th Edition) 

A 44 )J.m increase is observed by the moditied Forsythe- Hertwig fluidizing test method. 

Specialty alumina derived from the Bayer process resemble SGA, except for a higher a-Al202 content, which is usually 80%, and a lower surface area, typically 20 m /g. The remaining material is generally sodium P-alurnina (Table 2) formed as a result of the soda contamination common to the process (2—7). The mineralogical and stmctural properties of calcined aluminas are given in Table 2 (3). 

Phase CAS Registry Number Formula Crystalsystem Spac egro up Molecules perunit cell Unit a cell length, nm b c Density, g/cm  

Soft-burned calcined products having Ot-Al O crystals no larger than 1 Jm may include a considerable portion of transition aluminas (1 7) exliibit specific surfaces as high as 50 in /g. Most special calcined products are 80—100% a-M20 and have a specific surface area from 0.5 to 20 m /g. A considerable portion of the normal 0.3—0.6% Na20 contained in Bayer alumina is in the fomi of p-alumina, Na20 1 L5l20.  

---

ALUMDIUMCOMPOUNDS - ALUMINIUMOXIDE(ALUMINA) - CALCINED, TABULAR, AND ALUMINATE CEMENTS] (Vol 2)... 

Abrasives - [ALUMINUMCOMPOUNDS - ALUMINIUMOXIDE(ALUMINA) - CALCINED,TABULAR, AND ALUMINATE CEMENTS] (Vol 2) -m automobile polishes [POLISITES] (Vol 19) -for dental materials [DENTAL MATERIALS] (Vol 7) -for enameling [ENAMELS, PORCELAIN OR VITREOUS] (Vol 9) -nitrides as [NITRIDES] (Vol 17) -particle shape classification m [SIZE MEASUREMENT OF PARTICLES] (Vol 22) -phenolic resins PHENOLIC RESINS] (Vol 18) -PVB m [VINYL POLYMERS - VINYL ACETAL POLYMERS] (Vol 24) -silicon carbide m [CARBIDES - SILICONCARBIDE] (Vol 4) -standards and specification [MATERIALS STANDARDS AND SPECIFICATIONS] (Vol 16) -use m cosmetics [COSMETICS] (Vol 7) -use m electroplating cleaning pLECTROPLATING] (Vol 9)... 

---