THE RATIO OF DISSOLVING SURFACE-AREA GROWING SURFACE-AREA IN THE HYDROTHERMAL GROWTH OF QUARTZ

It was experimentally confirmed and theoretically proved that in the r ecrystallization of mineral substances through thermal gradient method s there exists a critical value of the ratio s = dissolving surface ar ea/growing surface area. In the simplest case when the dissolution and growth can be treated as first order reactions, the critical value is determined by the ratio of the rate constants of the two processes, s (cr) = k / k'. As long as the actual ratio of surface areas in an expe riment is greater than s(cr), the growth rate of the seed does not dep end on the surface areas, but when it becomes smaller than s(cr), the nutrient surface area becomes the rate determining step in crystal gro wth. In the hydrothermal recrystallization of quartz, a value of s(cr) equal to or smaller than 2 was found, which is smaller and more relia ble than the earlier proposed value of 5.