Synthesis of Chrysotile Fibers with an Addition of Magnesium Iodide under a Hydrothermal-Dehydration Process

Abstract

Synthesis of long chrysotile fibers was studied under hydrothermal dehydration process with an addition of magnesium iodide which had the same structure as the bromide and was found to be effective in the formation of the fibers.In this experiment free iodine appeared in the slurry by decomposition of hydrogen iodide formed by hydrolysis of magnesium iodide. When the slurry was subjected to hydrogen pressure at initial stage of the reaction, satisfactory results were obtained. The product was a layer like natural chrysotile ore bundled from fibers of the almost same length. Therefore, it was deduced that iodide contained in the intermediates was easily dissociated and the bundling of fibers was carried out at a smaller degree of disturbance as compared with the bromide.Crystal growth may be controlled by initial hydrogen pressure and dehydration velocities. The velocities were also controlled by the reactivity of metallic iron added to the outside of the slurry container.