Evaluation and beneficiation of silica sand and kaolinitic sandstone in south of Jordan
Silica sand (SS) samples from the Hanout area of Late Cambrian-Early
Ordovician sandstone and the kaolinitic sandstone (KS) samples from the Wadi
Es Siq-Rakyia area of Lower Cretaceous in south of Jordan were studied and
assessed as a source of glass sand.
A detailed mineralogical, geochemical, and grain size distribution analysis
was carried out using XRD, XRF, SEM, and binocular microscopy. Heavy
mineral separation was conducted using heavy liquids and spirals. Attrition
scrubbing trials were performed on various size fractions to assess the benefit of
attrition scrubbing in upgrading the silica sand.
Upgrading the silica sand included removing or reducing the content of
the contaminant oxides (i.e., Al2O3, Fe2O3, TiO2, CaO, and MgO) and the heavy
minerals. The aim of this project was to achieve this upgrading through the use of
inexpensive and relatively simple processing techniques. Kaolin was also
concentrated in the fine fraction after attrition scrubbing and wet screening of the
kaolinitic sandstone sample.
Following the initial sample characterisation at “bench scale”, a pilot plant
study was performed on bulk samples of both the silica sand and the kaolinitic
sandstone. A high-grade glass sand product of 500-125μm size fraction was
produced from both samples by dry and wet screening, attrition scrubbing and the
separation of heavy minerals using spirals. Due to the relatively low level of
impurities in the raw material, a high silica sand recovery was produced with a
high silica grade when the middling fraction was combined with that of the
The mass flowrate of the feeds and the products in the spiral was
calculated for both SS and KS samples as well as in the hydrocyclones for the –
125μm fraction of the KS sample. The amount of water required to operate the
pilot plant was calculated.
The high quality glass sand produced compared well with the Grade A
British Standard for glass sand. The silica sand product was clearly capable of being used in the high quality glass industry and in many other applications where
pure silica is required.
A kaolin-enriched product was produced from the –125μm wet screened
fraction of the kaolinitic sandstone following the use of small diameter
hydrocyclones. A moderate quality of kaolin with low recovery was produced
from the KS sample, which could be used in the ceramic industry for tableware