Papers by Author: Jun Jun Wu

Abstract: Pyrophyllite was the cheap, environmentally friendly alumina silicate clay minerals. This paper studied optimization of conditions for extraction of acid-soluble Al₂O₃ from pyrophyllite. Qualitative tests had been performed in studying pyrophyllite crystal at different temperatures by using scanning electron microscopy. Dissolution experiments showed that after thermal activation the behavior of alumina in acid the dissolution was different, which was affected by hydrochloric acid concentration, heat activation temperature and acid leaching time. When the calcinations temperature was 700 °C and hydrochloric acid concentration was 25%, the dissolution amount of alumina largest. The fit results indicated that the research for the relationship between dissolution and time by Using Exponential function series Asymptotic1 model to fitting match was the best. So the above function could be used to estimate each time the dissolution of alumina from pyrophyllite in hydrochloric acid.

Abstract: This paper studied the influence of heat treatment on the pyrophyllite structure and acid-soluble properties of alumina. Qualitative tests had been performed in studying pyrophyllite crystal at different temperatures by XRD, TG-DTA, FT-IR and quantitative analysis of Al2O3. The quantitative titration method studied the dissolve characteristics of the different heat treatment samples in different acid conditions, and then a numerical simulation was done. The results showed that at temperatures below 480 °C, the pyrophyllite did not change the basic structure. 480~700 °C dehydroxylation reaction occurred, and the structure water of pyrophyllite is removed, and then turned into partial pyrophyllite. Dissolution experiments showed that after thermal activation the behavior of alumina in acid the dissolution was different, which was affected by hydrochloric acid concentration, heat activation temperature and acid leaching time. When the calcinations temperature was 700 °C, the dissolution amount of alumina was largest. These works could provide some theoretical basis for further application of pyrophyllite research.