A method for manufacturing an inorganic polymer object from a precursor wherein the precursor comprises gibbsite-containing residue of the Bayer process or thermally processed gibbsite-containing residue of the Bayer process, wherein the precursor is free from, or comprises less than 0.01 wt% of one or more species selected from the group consisting of ground granulated blast furnace slag, basic oxygen furnace slag, kaolin tailings, coal gangue and silica fume, the method comprising the steps of: - alkaline-activating said precursor, - mixing the precursor, - shaping the mixed precursor and - hydrothermally curing the shaped precursor at a temperature between 70 °C and 350 °C, and under a pressure higher than 1 bar and less than 500 bar, whereby the precursor comprises up to 40 wt% one or more of a component selected from the group consisting of quartz sand, precipitated silica, natural clay, calcareous sand, thermally-activated clay, chemically-activated clay, mechanically-activated clay, fly ash from bituminous coal, subbituminous coal or lignite, gibbsite-containing electrostatic precipitation dust (ESP dust), aluminium salt cake, processed aluminium dross, CaCO 3, CaO and Ca 2, mono-, di- and tricalcium silicate, metallurgical slag, EN 197-1 blended cement, cement kiln dust, soda-lime-silica glass or other glass compositions, thermally processed bauxite residue and vitreous slag. wherein the precursor comprises gibbsite-containing residue of the Bayer process or thermally processed gibbsite-containing residue of the Bayer process, wherein the precursor is free from, or comprises less than 0.01 wt% of one or more species selected from the group consisting of ground granulated blast furnace slag, basic oxygen furnace slag, kaolin tailings, coal gangue and silica fume, the method comprising the steps of: - alkaline-activating said precursor, - mixing the precursor, - shaping the mixed precursor and - hydrothermally curing the shaped precursor at a temperature between 70 °C and 350 °C, and under a pressure higher than 1 bar and less than 500 bar, whereby the precursor comprises up to 40 wt% one or more of a component selected from the group consisting of quartz sand, precipitated silica, natural clay, calcareous sand, thermally-activated clay, chemically-activated clay, mechanically-activated clay, fly ash from bituminous coal, subbituminous coal or lignite, gibbsite-containing electrostatic precipitation dust (ESP dust), aluminium salt cake, processed aluminium dross, CaCO 3, CaO and Ca 2, mono-, di- and tricalcium silicate, metallurgical slag, EN 197-1 blended cement, cement kiln dust, soda-lime-silica glass or other glass compositions, thermally processed bauxite residue and vitreous slag. - alkaline-activating said precursor, - mixing the precursor, - shaping the mixed precursor and - hydrothermally curing the shaped precursor at a temperature between 70 °C and 350 °C, and under a pressure higher than 1 bar and less than 500 bar, whereby the precursor comprises up to 40 wt% one or more of a component selected from the group consisting of quartz sand, precipitated silica, natural clay, calcareous sand, thermally-activated clay, chemically-activated clay, mechanically-activated clay, fly ash from bituminous coal, subbituminous coal or lignite, gibbsite-containing electrostatic precipitation dust (ESP dust), aluminium salt cake, processed aluminium dross, CaCO 3, CaO and Ca 2, mono-, di- and tricalcium silicate, metallurgical slag, EN 197-1 blended cement, cement kiln dust, soda-lime-silica glass or other glass compositions, thermally processed bauxite residue and vitreous slag.