Preparation of filter aids based on Lam Dong diatomite

Abstract

Diatomite from Dai Lao valley, in Lam Dong province was selected for investigation of its possible application in preparation of filter aids. For this purpose, diatomite ore was leached in acids  to enrich SiO2 and  reduce  impurities, and  then calcined at high  temperatures  in order  to improve the material characteristics for use in filtration. The leaching was conducted in a hot 6M H2SO4 solution (90 – 95 oC) for a time period up to 36 h. To examine effects of temperature, the calcination temperature was varied in the range 900 – 1250 oC. The physical, chemical, thermal and micro–structural features of the raw and the calcined diatomite were determined to compare them with  those  of  the  commercial  filter  aids  currently  used.  It  is  shown  that  the Lam Dong diatomite can successfully be used for preparation of filter aids.