The study on the effective factors of hydrothermal synthesis in preparing high quality crystalline α-quartz powders

In this study powders of high quality crystalline α-quartz were prepared by hydrothermal synthesis and parameters related to the preparation of the material were investigated. The degree of face development of the α-quartz crystal depended on the relative growth rates of a particular form that varies considerably with the degree of supersaturation. reaction temperature, concentration of mineralizers, and the amount of seed crystals in the feedstock. In the temperature range of 240–450°C and the pressure range of 100–300 atm, alkali hydroxides and alkali halides such as KOH. NaOH. Na₂CO₃, KF, and NaF were found to be the effective mineralizers. As the concentration of mineralizers increased, the particle size of crystalline α-quartz powders became smaller at lower reaction temperatures The fractional size distribution of synthetic crystal powders depended on the hydrothermal conditions. As the reaction time and the amount of seed crystals increased, the width of particle size distribution became narrower. The weighl mean particle size was in the range of 1 μm to 10 μm. The characterization of the products were carried out using XRD, SEM, PSA, FTIR, and Raman spectrometer.