Silica-containing alkaline dispersions and their use in cleaning solid surfaces

An aqueous two-component composition useful for cleaning and degreasing hard surfaces consisting of as one component, (a) a strongly alkaline aqueous concentrate of about 50% by weight of sodium hydroxide or potassium hydroxide, and, as the other component, (b) an acidic or neutral activesubstance aqueous concentrate consisting of a silica dispersion containing from about 10% to about 30% by weight of silica selected from the group consisting of pyrogenic silica, precipitated silica and mixtures thereof, from 0 to about 5% by weight of a stabilizer for silca dispersions, from about 0.001% to about 40% by weight of a phosphorous compound selected from the group consisting of phosphoric acid and alkali metal polyphosphates neutralized to a pH of from about 6 to about 9, where up to about 50% of said phosphoric acid can be replaced by sulfuric acid, and from about 0.5% to about 10% by weight of a surfactant selected from the group consisting of anionic surfactants, nonionic surfactants, amphoteric surfactants and mixtures thereof, all weights based on the total weight of the active-substance concentrate (b), component (a) being present in an amount sufficient to cause an alkaline medium having a pH above about 12 when components (a) and (b) are combined prior to use.