Research on preparation and filtering effects of modified talc filter aid

ABSTRACT

To reduce the shortcomings of existing filtering assistance, the talc was modified by a two-step method. In the first step, the talcum powder was heated by microwave in the acid solution. In the second step, the talcum powder was stirred with Hexadecyl Trimethyl Ammonium Bromide (HTAB) solution for optimum time under an optimum temperature. The optimum temperature, time and amount of HTAB were investigated by the batch membrane filtration experiments of kaolin suspension. The filtering effects of the new talc filter aid were evaluated with the filtration rate and moisture content in filter cake. The results showed that the optimum conditions were: the amount of 0.05 mmol/L HTAB was 100 ml, the modified temperature was 80℃ and the modified time was 60 min. When the filtrate was accumulated to 25 ml, the filtration time was 13.21 s shorter than others. The membrane flux of microfiltration was the largest (0.024 L/m²·s) when new talc filter aid was added into the kaolin suspension. The talc powder was characterized by Fourier Transform Infrared Spectroscopy and X-ray diffraction, which made the experimental results more obvious. Characterization results indicated that the hydrophobicity of the talc filter aid was excellent because microwave-assisted acidification talcum powder could absorb the cationic surfactants by electrostatic interactions. Finally, by comparing talc filtration assist with diatomite filtration assist, it is concluded that the filtration performance of talc filtration assist kaolin suspension is superior to other materials.

Keywords
Talcum powder; Modification; Cationic surfactants; Filter aid; Microwave