PQ soluble silicates are used effectively as binders where heat stability or resistance to chemicals is required.  Silicate binders develop high green strength by air-setting without heat.  They also impart increased fired strength.  Consequently, air-setting specialties containing soluble silicates are used in refractory mortars and ramming, gunning, and patching mixes in practically all refractory or chemical-resistant construction and in their maintenance.