Abstract:
Vein quartz is the major source of silicon for
manufacturing of solar cells, computer chips, and silicon
carbide. The aim of the investigation was to enhance the
purity of exporting semi processed vein quartz by acid
leaching. Particle size reduction processes crushing,
grinding and milling increase the amount of iron in the
quartz and this secondary iron concentration needs to be
removed to produce more purified quartz. Thus, in this
research quartz was obtained using raw quartz near
Badulla area. Raw quartz was processed using primary
and secondary crushers and then it was separated into
four size fractions (125μm, 500μm, 1mm, and 8mm). Acid
leaching was employed for iron removal. Atomic
Absorption Spectrophotometer (AAS) was used to
measure iron content before and after the leaching. As
preliminary studies, Hydrochloric acid (HCl) and Nitric
acids (HNO3) were employed for the leaching and Liquid-
Solid ratio was 5:1. According to the results which were
observed as preliminary study HCl was chosen for the
leaching and effect of the HCl for the removal of iron was
examined. The particle size of the quartz, leaching time,
concentration of the reagents was used as parameters.
Leaching was done under normal atmospheric conditions
(250C, 1atm). The acid leaching of vein quartz resulted in a
reduction of 60 – 65% iron from the original value. Since
iron dissolution is a photochemical reaction practical was
conducted in controlled conditions (250 – 500 lux).
Progressive amount of leaching (60 – 65%) of iron from
quartz was obtained under following conditions, a higher
concentration of HCl (5M), smallest size fraction (0-
125μm), and 60 hrs. leaching time. Under these conditions,
higher purity of quartz powder can be achieved.
