A method for the alkaline digestion of soda-lime glass comprising forming a mixture of soda lime glass and a hydroxide solution, the mixture having at least 100 grams of glass per litre of H2O, the hydroxide solution having a concentration of 1M or greater to thereby form an aqueous sodium silicate fraction having a silicate concentration of 50 g/L or greater (calculated as SiO2 equivalent) and a ratio of SiO2:M2O of at least 1, wherein M2O is an alkaline metal oxide, by digesting the glass in the mixture; and separating the aqueous sodium silicate fraction from solids. The solids contain calcium silicate hydrate and undissolved glass. The calcium silicate hydrate can be CSH treated with an acid to thereby dissolve soluble metals from the CSH and separating a liquid phase from a solid phase, the solid phase comprising SiO2 or silica gel.

An apparatus for producing pozzolanic material from waste includes a glass separator unit to remove glass material from the waste and a size reduction unit downstream the glass separator unit. The glass separator unit includes an outer member and a wound member positioned within the outer member and defining an open central bore. The outer member and the open central bore define respective longitudinal axes extending on a common plane that are disposed at an angle relative to a horizontal reference plane, with the inlet higher than the outlet. Non-glass/non-ceramic material is output through the open outlet end of outer member utilizing a flow of separation fluid. The glass/ceramic material is output to the size reduction unit through the open inlet end of the outer member utilizing the rotating wound member of the glass separator unit.

A method for recycling glass scrap from exhausted photovoltaic panels containing organic and substantially lead-free contaminants which allows obtaining industrial-degree liquid sodium silicates and mixed inorganic silicates insoluble in water and in alkaline solutions having a high number of industrial applications. The embodiments also relate to soluble and insoluble silicates obtained by such a method.