Silica was prepared by alkali dissolution-precipitation with oil shale as starting material

and the content of SiO2 in oil shale was reduced.The detailed processing conditions were as follows: molar ratio of NaOH to SiO2 was 4

mass ratio of water to oil shale was 1

the treating condition was at 100℃ for 6 h

and grain size was more than 0.15 mm.Then acid leaching of oil shale was performed to prepare γ-Al2O3

and the content of Al2O3 and Fe2O3 in oil shale was reduced too.The acid leachate solution was modulated to pH＝12.0 by adding alkali solution

and a mixture of γ-Al2O3 and Fe2O3 was precipitated and filtered

then γ-Al2O3 and Fe2O3 were separated completely by adding acid solution to pH＝6.0.Finally

the treated oil shale had a kerogen content of 71.6％ and the kerogen was validated by FT-IR.