Abstract:
Zircon is one of the most important among the heavy minerals occurring in
the beach sand along the coastal belt of Bangladesh. The prescnt work
attcmpts to make chemical and mineralogical eharaeten7..ation of zircon
benelkiated at the Cox's Bazar Pilot Plant of Bangladesh Atumk Energy
Commission (BAEC). The mineral is investigated by means of chemical
analysis, optical microscopy and X-ray diffraction (XRD). Potentiality of
Bangladesh zircon as a raw material for zirconia, opacilier and re1i:actury
brick production is also examined. From the chemical analysis it is found
that Bangladesh zircon has 95.88% purity. The main impurity in Bangladesh
zircon is titanium oxide (3.01%). This is followed by iron oxide (0.42%).
Tnlce amounts of other oxides are also found. From the mineralogical study
it is found that Bangladesh zircon have an elongated, prismatk shape with
pyramidal termination in half of the grains and the rest are more or less
rounded. Some fractured and irregular grains arc also found. Bulk sample of
Bangladesh zircon in the as-received condition shows golden yellowish
brown color. However, individual grains were found tu be almost colorless
an d tnmsperent under polari7ed light. XRD study confmned good
crystallinity in the sample. Under the microscope, it is found that in
Bangladesh zircon, zircon grains constitute 94% and tutal impurities amount
to 6%. This result agrecs fairly well with the chemical analysis resuIL~. The
main impurities in thc prcsent sample of Bangladesh zircon are found to'be
oxides of titanilUTl(both rutile and ilmcnite). This is also consistent with the
finding~ uf chemical analY8is. Further, monazitc was identified as an
important impurity under the microscopc. Most of the impurities found in
Bangladesh zircon exist as discrete minerals. As a result, it should be
possible to remove these impurities fairly casily by physical mineral
processing methods and thereby impnwe the grade of Bangladesh zircon.
The iron bearing coating found on ,orne zircon grains can be removed by
acid washing. In the disintegration cxperiments, it has been found that the
heating pcriod of 30 minutes is not sufficient to result in eomplele
di8inlegration of Bangladesh zircon into zirconia even at the highest
temperature (1500"C) and the largest sodium oxide concentration (30%)
used in the present 8tudy. Practical experiments have demonstrated that
Bangladesh zircon i~ quite 8atisfactory for preparation of zircon flour in
ce"lmic indmtries. Zircon flour made from 13angladesh zircon can
effectively replace imported zircon 110ur, if adequate size reduction and
purification is earned ouL Bangladcsh zircon can also be used successfllily
ji,r preparation ofrelmdory bricks for high temperature use.
