EXPERIMENTAL RESEARCH INTO IRON REMOVAL FROM K-FELDSPAR POWDER BY ACID LEACHING

When the K-feldspar containing ferric and ferrous impurity is used to synthesize zeolite molecular sieves and to extract potassium carbonate, the ferric and ferrous impurity may decrease the whiteness of zeolite. Iron removal experiments by leaching with sulfuric acids were performed for three K-feldspar powder samples, selected from Pinggu of Beijing, Jixian of Tianjin, and Baiyun Ebo district of Inner Mongolia, respectively. For the K-feldspar powder materials from Pinggu, Jixian, and Baiyun Ebo, the most leaching proportions of iron was 88.6%, 93.2%, and 64.6%, respectively. For the former two K-feldspar powders, iron leaching was performed in a similar way, resulting in a higher efficiency of their iron removals than that for Baiyun Ebo K-feldspar powder. The influential factors for iron removal efficiency, such as sulfuric acid concentration, temperature, and reaction time, were studied with orthogonal experimental method. These factors worked distinctly for K-feldspar powders from different areas. The experimental results also shows that the iron dissolved fast at the beginning of the leaching reaction, and then the corresponding reaction rate slowed down. For these two reaction periods, the reaction rates were mainly governed firstly by chemical reaction, and then by diffusion.