High alumina fly ash (FA

HAl

) is a kind of bulk solid waste unique to China

whose availability of high-value aluminum and the threat to the environment makes its high-value utilization urgent. In this work

the alumina containing leaching solution obtained from Na

2

CO

3

roasting and HCl leaching of FA

HAl

was used as the mother liquor to prepare layered boehmite

in situ

. The preparation process with AlCl

3

as the raw material was also compared. The formation process and mechanism of boehmite

the choice of solvent

along with the adsorption capability of Congo red were analyzed by X-ray diffraction

scanning electron microscopy

Fourier transform infrared spectroscopy

Brunauer-Emmett-Teller method and adsorption experiments. Results showed that during the preparation of layered boehmite

the precursor Al(OH)

3

from the reaction of Al

3+

and OH

-

is transformed into boehmite

γ

-AlOOH. The existence of ethanol is beneficial to regulate and promote the growth of boehmite crystal effectively. When water and ethanol are mixed with a volume ratio of 2:1 and used as the solvent

the maximum specific surface area of the boehmite is obtained at 135.7 m

2

·g

-1

and 99.16% of Congo red can be absorbed after 10 min when AlCl

3

is used as a raw material. As purified leaching solution is used as the mother liquid

the crystallinity of boehmite decreases sl

ightly when the pH value decreases from 12.5 to 11. When pH is 11

the removal efficiency of Congo red reaches a maximum of 72.25%. This process not only achieves the extraction of aluminum and high-value utilization of FA

HAl

but also provides a thought to prepare layered boehmite with adsorption properties.