Abstract
M.Tech.
Artisanal mine of sandstones especially in rural area are facing numerous
challenges including the use of inadequate tools for the processing of sandstones.
Since the current processing technique has limitations which consist of the use of
hammer and chisels, there is a need to develop environmentally friendly and cost
effective techniques for the processing of sandstones. In this project, six different
sandstones samples (yellowish, blackish, reddish, greenish, greyish and whitish)
from QwaQwa rural area were collected and characterized using X-ray diffraction
(XRD), X-ray fluorescence (XRF), scanning electron microscopy coupled with
energy dispersive X-ray spectroscopy (SEM/EDS) and an optical microscope. In
addition, physical properties of sandstones were also carried out including
compressive strength, dielectric properties and water absorption. Furthermore
sandstones samples were irradiated using multi- and single- mode microwave
cavities to investigate the effect on the mineralogy of sandstones. The analysis of
mineralogical change was carried out using XRD. Additionally a microwave
multimode cavity was used to investigate the weight loss of sandstones after being
irradiated. A microwave cavity was designed based on the characteristics of
sandstones and it was simulated. A photovoltaic solar system was sized to power
the microwave cutter. The experimental work was carried out on a laboratory
scale. The XRD analysis revealed that quartz was the major mineral present in all
sandstones which confirms that QwaQwa sandstones are quartz based
sandstones. Feldspar minerals such as illite and albite were also found. Additional
minerals were identified at trace level including glauconite, kaolonite, crysobalite
and orthoclase. On the other hand, the XRD results of the irradiated samples
using a single- and multi- mode cavity for 60 seconds revealed a strong presence
of quartz which means no significant changes were observed. However, some
minor overlapped peaks suspected to be muscovite (KAl2(Si3Al)O10(OH,F)2) in
three samples (blackish, greyish and yellowish) were noticed. XRF study showed
that the chemical elements available in the six sandstones samples are:
aluminium, calcium, iron, potassium, magnesium, manganese, sodium,
phosphorus, silicon and titanium.