Hydroxides silicate gels

In 1992, R.M. Laine (University of Michigan, Ann Arbor) announced the development of a process that transforms sand and other forms of silica into reactive silicates that can be used to synthesize unusual silicon-based chemicals, polymers, glasses, and ceramics. The Lame procedure produces pentacoordinate silicates directly from low-cost raw materials—silicon dioxide,ethylene glycol, and an alkali base. The mixture is approximately a 60 1 ratio of silica gel, fused silica (or sand) to metal hydroxide and ethylene... 

In the first place, we learned more about the formation of nickel hydrosilicates under certain circumstances from an investigation of Van Eijk van Voorthuysen and Franzen (2). These investigators made a number of preparations by combining boiling dilute solutions of nickel nitrate and alkali silicate in various proportions. In order to find out to what extent co-precipitation is required for the formation of hydrosilicate structures, acid was added to a nickel hydroxide suspension in a silicate solution by which silica is precipitated, or conversely, alkali was added to a suspension of silica gel in a nickel nitrate solution. Some of the preparations were subjected to a hydrothermal treatment at 250° C. for 50 hrs. with a sufficient quantity of water for developing the best possible structure. 

Mixed oxides have a widespread application as magnets, catalysts, and ceramics. Often, nonstoichiometric mixtures with unusual properties can be prepared for example, Fe203 and ZnO have been milled for the production of zinc ferrite [40], while mixed oxides of Ca(OH)2 and Si02 were described by Kosova et al. [77]. Piezoceramic material such as BaTi03 from BaO and anatase Ti02 has been prepared [78], while ZnO and Cr203 have been treated by Marinkovic et al. [79] and calcium silicate hydrates from calcium hydroxide and silica gel by Saito et al. [80]. The thermal dehy-droxylation of Ni(OH)2 to NiO or NiO-Ni(OH)2 nanocomposites has also been investigated [81]. 

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