Thermoluminescence Study of Based Materials of Ceramic Tiles

Many flooring materials most of them are in natural form are used to manufacture floor tiles for household flooring purpose. The peoples demand for variety of flooring material Leeds to develop various types of ceramic tiles. In India ceramic industry is fast growing one, more then 500 units of manufacturing ceramic tiles, vitrified tiles and sanitary ware, situated around Morbi, Rajkot, Gujarat, India. Many natural minerals are used as the raw materials required for the manufacturing ceramic ware. The following minerals are used to manufacturing the ceramic tiles i.e. Quartz, Feldspar, Zircon, Talc, Grog, Alumina oxide, etc. Most of the minerals are from Indian mines of Gujarat and Rajasthan states, some of are imported from Russian sub continent. The present paper reports the thermoluminescence characteristics of Feldspar, Alumina and Quartz minerals collected from the ceramic tiles manufacturing unit, Morbi. The as received minerals TL was recorded (NTL), and annealed and quenched from 400 o C followed by 15Gy beta dose given from Sr-90 beta source TL was recorded and the comparative TL (Thermoluminescencs Study) study of above materials are presented and it represent some special characteristics of the materials.


Introduction
Many natural mineral are used to manufacture floor tiles for household floorings. The demand of a variety of flooring materials has lead to develop various types of ceramic tiles. In India the ceramic industry is one of the fastest growing industries, more then 200 manufacturing units of ceramic tiles, vitrified tiles and sanitary wares are situated at Morbi (Rajkot District, Gujarat state, India). Many natural minerals are used as the raw materials for the manufacturing ceramic wares. The minerals used in manufacturing the ceramic tiles are Quartz, Feldspar, Zircon, Talc, Frit-O, Frit-T, Aluminium oxide, Sodium trypoly phosphate China clay, Bikaner clay, etc. Most of the minerals are from mines in Gujarat and few are from Rajasthan state and imported from Russia. The phenomenon of TL has been studied by many investigators. The thermoluminescence (TL) study in geology, particularly for natural minerals, is an important research tool. The TL study of minerals commonly used in ceramic tiles industry, such materials gives better understanding about their properties and characteristics. The systematic study of TL of such minerals is helpful to solve the basic raw materials quality problem the ceramic tiles industries.

Experimental method:
The natural minerals used in manufacturing ceramic tiles are collected from the ceramic tiles industry. Most of the materials used for the TL analysis were indigenous ones and a few were imported minerals. First make a fine powder of such mineral and then 5mg powder of each materials are taken and placed this powder between circular ring and then put Sr 90 Beta source on it for twenty min. for irradiation. The source capacity is 500rad./min. after irradiation the sample is collected from the circular ring and placed into the TL (Thermoluminescence) reader. TL of these minerals was recorded using TL set-up supplied by Nucleonix Systems, Hyderabad 1 . Irradiation was carried using Sr-90 beta source. Equal quantities of samples (5 mg) were used for the analysis.

Figure-3
Thermal Annealing Treatment: Thermal annealing for the specimen was carried out in the muffle furnace. The laboratory muffle furnace has temperature range up to 1200 o C and the size of chamber for sample heating was 22cm × 10cm × 10cm. The temperature was maintained with ±1 o C accuracy using a temperature controller, which supplied required current to the furnace. Power supply of 230V was provided to the furnace. A silica crucible containing a powdered form of virgin specimens was kept in the furnace at required annealing temperature for desired time. After completion of annealing duration the specimens were rapidly air-quenched to room temperature by withdrawing the silica crucible on to a ceramic block. Such material or specimens are called "annealed and quenched" or "thermally pre-treated specimen"

Results and Discussion
TL Study of Quartz: Figure-4 is the TL of 5mg of weighed powder was taken to record TL glow curve of Quartz (NTL) without any pre heat treatment and irradiation. The glow curve exhibit one hump like glow peak at temperature at 332 0 C. There is no good TL is observed.    Figure-10 shows the TL glow curve of Feldspar mineral with out any pre heat treatment and irradiation .The glow curve exhibits one well resolved peak at 308 0 C temperature ,here heating rate is 4 O c/sec for TL measurement the intensity of peak is 76au noted this intensity is remarkable this sample gives TL without any pre heat treatment this result is interesting here phase changed thrmoluminescence is occurs .some mineral contain water molecule due to this result the phase change TL Research Journal of Material Sciences ____________________________________________________________ ISSN 2320-6055 Vol. 1(8), 1-7, September (2013) Res. J. Material Sci.
produced . Here till temperature 170 0 C the intensity remain near to zero but then after intensity continuously increasing with temperature .From this result it is noted that one trap with large numbers of carriers generated with peak 308 0 C. Figuew-11 shows the TL glow curve of Feldspar mineral irradiated with beta dose of 15 Gy by Sr 90 here no any pre heat treatment is given to the sample, here two well resolved glow peak occurs at temperature 141 0 C and 312 0 C it is indicate that two traps with large carriers is related with this temperature range here the intensity of peak is 43au and 39au respectively, here it is noted that the intensity of peak 309 0 C in in Figure-2.1 is decreased in Figure-2.2 and the peak temperature slightly change from 309 0 C to 312 0 C it shows fading effect but one remarkable result is that one new peak occurs at temperature 141 0 C with intensity 43au this peak is well resolved and stable so it is considered as dosimetric peak.  Figure-12 shows the TL glow curve of Feldspar mineral with pre heated at annealing and quenching temperature at 400 0 C and irradiated with beta radiation dose of 15Gy by Sr 90 ,here heating rate is 4 O c/s for TL measurement,here one well resolved glow peak occurs at temperature 123 0 C and peak intensity of 39au is recorded, with comparison of Figure-2.3 it is clear that peak temperature almost remain same but the peak intensity is decreased about 40%, this interesting this shows the fading effect occurs between temperature range of 200 0 C TO 400 0 C into the material also broad hump is produced in the glow curve.  . 1(8), 1-7, September (2013) Res. J. Material Sci. Figure-13 shows the TL glow curve of Feldspar mineral with pre heated at annealing and quenching temperature at 600 0 C and irradiated with beta radiation dose of 15 Gy by Sr 90 ,here heating rate is 4 O c/s for TL measurement ,here one well resolved glow peak occurs at temperature 114 0 C and peak intensity of 51au is recorded, with comparison of Figure-2.4 it is clear that no major occurs into the result except peak temperature slightly change from 123 0 C to 114 0 C and intensity decreased from 34au to 51 au so it is noted that after 400 0 C temperature treatment more carrier oriented trap is formed that's why TL intensity is increased but minor variation occurs in peak temperature it shows the stability of peak.   Figure-16 shows TL glow curve of Alumina with out treatment of heat and irradiation dose. This glow curve exhibits one peak at temperature 159 0 C and intensity of 0.11au here no significant TL is recorded, the material exhibits low TL sensitivity in natural form. Figure-17 shows TL glow curve of Alumina with irradiated with beta dose of 15 Gy by Sr 90 . The glow curve exhibits one peak at temperature 257 0 C and with intensity of 34au, here it is noted that after irradiation the intensity of TL is increased it is means that that large carriers oriented trap is generated. Figure-18 shows the glow curve of Alumina treated with annealing and quenching temperature of 400 0 C and irradiated with beta source of 15 Gy. Here glow curve exhibits one well resolved peak at temperature 275 0 C and intensity of 48au also one broad hump is developed. It compare with Figure-4.3 the intensity is increased from 19au to 48au it is noted that after the treatment of AQ400 0 C more carriers oriented trap is formed and it released it when it heated for TL measurement. The heating rate for TL is 4 O c/s.The peak 275 0 C is conceder as stable peak it indicate stability of material also this peak is interesting for dosimetri point of view.

Conclusion
The natural TL [NTL] observed in Above minerals under study as well as NTL+ATL followed by the TL observed from annealed and quenched form 400 o C and 600 0 C followed by beta irritation leads to the conclusions the results are due to the traps formed by irradiation as well as heat treatment to the subjected mineral.
The systemic study may be more useful in checking the purity of the raw materials which in turn leads to improving the quality of ceramic tiles in ceramic industries. Further studies are in progress.