Influence of sintering temperature on raw and beneficiated clay “Klokoti”

Marina Jovanovic,Tatjana Volkov-Husovic

doi:10.2298/sos1202161j

Abstract

The raw clay ?Klokoti? from middle Bosnia was beneficiated by method of wet separation which results in removing fraction over 20 ?m. The raw clay was characterized by chemical composition, grain size distribution and characteristic temperatures on heating microscope. The beneficiated clay was characterized by chemical composition and characteristic temperatures. The phase composition of raw and beneficiated clay was observed by RDA while the microstructure was monitored on scanning electron microscope (SEM). The sintering process was performed at 1100?C, 1250?C, 1320?C and 1400?C with two hours holding time at the highest temperature. The obtained results indicate a big content of coarse quartz in raw clay and gradually increase of crystalline mullite content with increasing temperature of sintering. Beneficiated clay at higher temperature of sintering produces larger glassy phase content, which is result of larger fluxing content in its composition. It is also observed that from beneficiated clay by sintering at 1250?C crystallize the most mullite along with minimum porosity and the lowest glassy phase content.

Highlights

Clays, like most mineral raw materials, often do not comply with the physical, chemical or technical requirements for certain production
The reduction of SiO2 in beneficiated clay indicates that raw clay contains coarse particles of quartz that are removed
The results of investigation show that due to beneficiation process conditions of mullitization are significantly changed as well as the quantity and composition of the glassy phase, which lead to large differences in the structural and phase composition of the clay

Summary

Introduction

Like most mineral raw materials, often do not comply with the physical, chemical or technical requirements for certain production. They usually require some processing operation or beneficiation to prepare them for further processing [1]. The wet method is the most frequent method of beneficiation of clay. It consists of following steps: mixing clay with water to make slurry, settling of coarse grains, separation of suspension with fine grains from sediment and dewatering of suspension. The theoretical basis for this process is the Stokes' Law, which defines the speed of the falling ball through fluid:. Stokes law applies to the ball diameter 0.2 to 200 μm [3]

Materials and experimental procedure

Results and discussion

Conclusion