Effects of titration speed on preparing nano-NH_4AIO(OH)HCO_3

NH_4 AlO(OH)HCO_3,the precursor of nano- Al_2 O_3,was prepared by homogeneous precipitation meth- od using NH_4Al(SO_4)_2 and NH_4 HCO_3 as raw materials.Effects of titration speed on preparing precursors were identified in the paper.The results indicate that titration speed has a great influence on preparing precursors. Nano-NH_3AlO(OH) HCO_3 is prepared by adding an aqueous solution of NH_4 Al(SO_4)_3 drop by drop to an aque- ous solution of NH_4HCO_3 at a titration speed of 3ml/min.When titration speed is low,the product is pure AACH crystals.When titration speed is high,the product containsγ-AlOOH little.And titration speed is low- er,the size of precursors is smaller.