<p>The most interesting and characteristic property of silicate solutions is their ability to react with various activators to form solutions and gels with different viscosities. Moreover, the structure and distribution of these species are highly dependent on activators of various organic and/or inorganic components. In this study, the rheological control on the properties of sodium silicate solutions by introducing Na-polyacrylate and acid additives, strong (phosphoric acid) and/or weak (silicic acid), has been elucidated. Solutions containing Na-polyacrylate can be highly viscous. Polymer molecules create intermolecular interactions and entanglements among the water molecules in the silicate solution, thus providing an interpenetrating high viscosity network solution system with increased viscosity. Acid-treated silicate solutions tend to exhibit very high viscosity and are converted into a polymerized, semi-solid gel, making them difficult to handle. Therefore, it is necessary to reduce the viscosity by rheologically controlling the gelation rate and gelation process of the silicate solution. Through this, the material can be kept in a state that is easy to handle or inject until curing and solidification occur. Another objective of this study is to provide the viscous silicate solution compositions for extinguishing metal or Li-battery fires, which are difficult to suppress. Water molecules within the viscous solution act as structural components, enabling fire suppression by simultaneously applying suffocating and cooling effects without steam explosions or hydrogen explosions, which are sometimes observed in certain aqueous fire-extinguishing agents for metal fires.</p>