Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 77. (Budapest 1985)

Szendrei, G. ; N. Tóth, M.: Contribution to the study on the crystallinity degree of kaolinites

50 100 Fig. 1. Diagram of CCI versus DO DO [%] highest rate and the loss of weight. They recognized a relationship between decomposition temperature at highest rate and the degree of order (temperature decreases with increasing disorder). The temperature of the exothermic peak can also reflect the degree of disorder (SMYKATZ-KLOSS 1974): for well ordered kaolinites 980-1005°C, while for disordered ones down to 940°C. MURRAY (1954), as also cited by NEMECZ (1973), pointed out relationships between the degree of disorder in kaolinites and the difference between the starting and end temperatures, height of the endothermic and exothermic peaks, difference between the end temperature of the endothermic peak and starting temperature of the exothermic peak, and the slope of the curve, respectively. Ordered kaolinites show higher values for temperature and intensity of the endothermic and exothermic peaks, greater difference between the starting and end temperatures of the endotermic peak, increasing slope between the endothermic and exothermic reaction, and a small endotermic peak before the exothermic one. Materials and methods r f'llP' B M fftljjl The kaolinite samples from Keokuk (KELLER et al. 1966), Királyhegy (NEMECZ 1973, 1980), Kovaso (PETROV 1963, PETROV & CHUKHROV 1978, 1979) and Sasca-Montana (RADULESCU & DIMTTRESCU 1966) are of hydrothermal origin, while others from Cserszegtomaj (BARDOSSY 1961),