Study on the flocculability of the bentonite modified by different alkyl quaternary ammonium salts

Bentonite is modified separately using tetraethyl ammonium bromide((Et)4NB),molecular deposition filming flooding agent (MDFFA),dodecyl trimethyl ammonium bromide (DTAB) and hexadecyl trimethyl ammonium bromide (CTAB) as modifying solvents.The modified bentonite is characterized by X-ray diffraction (XRD),Fourier transform infrared spectrometer (FT-IR) and spectrophotometer analysis methods.The results show that,alkyl quaternary ammonium salts enter between the crystal layers of bentonite,which makes the water content between the crystal layers of bentonite decrease.Among the four modifiers,the molecular deposition filming flooding agent (MDFFA) makes the water content decrease the most.The alkyl quaternary ammonium salts of high concentration all have definite flocculation to bentonite,there is a maximum of settling volume of bentonite with increasing of the concentration of alkyl quaternary ammonium salts.Comprised with tetraethyl ammonium bromide((Et)4NB),dodecyl trimethyl ammonium bromide (DTAB) and hexadecyl trimethyl ammonium bromide (CTAB),molecular deposition filming flooding agent (MDFFA) of lower concentration has better flocculation to bentonite.The settling time of bentonite in molecular deposition filming flooding agent (MDFFA) or dodecyl trimethyl ammonium bromide (DTAB) solvent is shorter than in tetraethyl ammonium bromide ((Et)4NB) or hexadecyl trimethyl ammonium bromide (CTAB) solvent.