Silicate-based substitution process

Because these processes require reduction and reoxidation of the silicon, they require large amounts of energy per unit of product. This makes them inherently unattractive and makes a search for replacements for them worthwhile. This naturally leads to a consideration of the silicate-based substitution approach to these compounds. 

Alternative Process Aids. Numerous substitute process aids have been evaluated for possible use in the hot water flotation process. Indeed, this is probably the subject of the majority of patents directed at oil sand processing. It should be fairly obvious that if sodium hydroxide is a suitable process aid then other alkaline agents could be used as well. Research by many investigators has borne this out over the years. Other bases, including silicates and phosphates have been studied in some detail [122]. Some of these alternative alkalis have performance advantages over NaOH. The main reason NaOH has remained in commercial use over three decades has been economic. 

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