Method for the isolation of aluminum, silicon and iron compounds from a raw material composition comprising at least aluminium, silicon and iron, comprising the steps of: a) grinding the raw material to produce raw material particles with a grain size of 50-100 micron; b) leaching an organic part of the raw material using a base to afford a solid residue A; c) drying and calcining the solid residue A to afford a calcined product B; d) leaching oxides of aluminum and iron from the calcined product B by treatment with aqueous sulfuric acid having a concentration of 30-60 wt.%, wherein the weight ratio of product B to sulfuric acid is from 1:3.5 to 1:4.5, to afford a sulfate solution C1 and a solid residue D1; e) separating the sulfate solution C1 from the solid residue D1 and treating the sulfate solution C1 with a hydroxide salt to obtain an insoluble metal hydroxide precipitate E and a remaining solution C2; f) separating the metal hydroxide precipitate E from the remaining solution C2; g) drying and calcining the metal hydroxide precipitate E at elevated temperature to afford a product F containing Fe 2 O 3; h) treating the remaining solution C2 from step f) with sulfuric acid to afford an aluminum sulfate containing solution G; i) treating the aluminum sulfate containing solution G with ammonia hydrate to afford an Al 3 -precipitate H; j) separating and calcining precipitate H at elevated temperature to afford Al 2 O 3; k) treating the separated solid residue D1 from step d) with a hydroxide solution to obtain an orthosilicate containing solution I and a remaining solid residue D2; l) separating the orthosilicate containing solution I from the remaining solid residue D2 and treating the orthosilicate containing solution I with hydrochloric acid to afford a silicic acid precipitate J. a) grinding the raw material to produce raw material particles with a grain size of 50-100 micron; b) leaching an organic part of the raw material using a base to afford a solid residue A; c) drying and calcining the solid residue A to afford a calcined product B; d) leaching oxides of aluminum and iron from the calcined product B by treatment with aqueous sulfuric acid having a concentration of 30-60 wt.%, wherein the weight ratio of product B to sulfuric acid is from 1:3.5 to 1:4.5, to afford a sulfate solution C1 and a solid residue D1; e) separating the sulfate solution C1 from the solid residue D1 and treating the sulfate solution C1 with a hydroxide salt to obtain an insoluble metal hydroxide precipitate E and a remaining solution C2; f) separating the metal hydroxide precipitate E from the remaining solution C2; g) drying and calcining the metal hydroxide precipitate E at elevated temperature to afford a product F containing Fe 2 O 3; h) treating the remaining solution C2 from step f) with sulfuric acid to afford an aluminum sulfate containing solution G; i) treating the aluminum sulfate containing solution G with ammonia hydrate to afford an Al 3 -precipitate H; j) separating and calcining precipitate H at elevated temperature to afford Al 2 O 3; k) treating the separated solid residue D1 from step d) with a hydroxide solution to obtain an orthosilicate containing solution I and a remaining solid residue D2; l) separating the orthosilicate containing solution I from the remaining solid residue D2 and treating the orthosilicate containing solution I with hydrochloric acid to afford a silicic acid precipitate J.