PROPERTIES AND POTENTIAL OF LAO KHAM VARISCITE’S APPLICATION IN CHEMICALLY BONDED PHOSPHATE CEMENT

Abstract

This study aimed to investigate properties and applications of Lao Kham Variscite, LKV,
variscite at Lao Kham village Roi Et province Thailand. The sample properties were investigated using
microscopic characteristics analysis with digital stereomicroscope, Petrographic analysis with thin-section
analysis, chemical compositions, and mineral analysis. The applications of LKV in chemical cement were also
investigated using setting time and compressive strength. The results indicated that the randomly selected
sample was itself a composite with several crystalline in microstructure characterization most of all were silica
oxide (SiO2) and some part of Variscite (Al(PO4)(H2O)2) clearly the sample needed to be screened for more
composition of Variscite before continuing the experiment. It was also found that calcination affected the
mineral state of LKV, all samples that had calcined were not found in Variscite, but the mineral composition
changed to Aluminum Phosphate (AlPO4) and non-calcined sample (LKVNOR) found no formation when
mixed with 3M NaOH solution while LKV600 had the fastest setting time and compressive strength compared
with the reference cement. In the summary LKV 600 was the most reactive and has the potential to be
developed for use as Chemically Bonded Phosphate Cement (CBPC).