STUDY ON TREATMENT OF LAM DONG DIATOMITE FOR FILTER AID MANUFACTURE

Abstract

Recent years in Vietnam, diatomaceous earth has been attractive to researchers and manufacturers due to its applications, particularly in the field of filter aid manufacture. In this study, diatomite from Dai Lao valley deposit (Bao Loc, Lam Dong province) was seclected for investigation of its possible application in preparation of filter aids. For this purpose, diatomite ore was characterized and treated in different acids in order to improve the material characteristics for filter aid manufacture. Chemical and physical properties of the raw and treated diatomite were determined using different instruments such as X-ray fluorescence (XRF), X-ray diffraction (XRD), differential thermal analysis (DTA) and scanning electron microscopy (SEM). The obtained results showed that Lam Dong diatomite has low SiO2 (52.9%) and high Fe2O3 content (5.32%). In order to enrich SiO2 and eliminate unnecessary components, different acids (6M H2SO4, 3.5M HCl and 5M HCl) were used. Among acids used, leaching in 6M H2SO4 gave most favorable results. Particularly, after leaching in 6M H2SO4, SiO2 content increased to 90.9% and Fe2O3 content decreased to 0.53%.