Flotation Chemistry Of Directly Flotation Of Soluble Potash

Soluble potash salts, including potassium chloride and potassium sulfate which are main resource to produce fertilizer, are rare minerals in china. As the increasing requirement of potash for agriculture, Chinese government spends plenty of foreign change on potash import. Now, about 90% of potash is depending on import in china. Potash salts mainly exist in salt lakes, such as Qinhai Salt Lake, in china. There are many methods to extract potash form other soluble salts, directly flotation method is widely used among them, because this method is easy to be controlled and adaptive to ores containing variable KCl content.Usually, the solubility of potash salts along with other salts is high in solution. The flotation process happens in the saturated solution of these salts(1) In terms of colloid chemistry of collector, the influence of solution pH on the character of ODA was investigated in this thesis. The effect of flotation mother liquids on the flotation behavior of ODA, such as the adsorption states at the air/liquid interface and KCl crystal surface were studied. The results show that the difference of ODA flotation behavior is mainly caused by the Mg2+ ion. Inducing Mg2+ ion into the flotation system will increase the ionic strengthen and the viscosity of the brine, which leads to the low mobility of the solution. In this regard, the dispersion the collector is also inhabited.(2) Contact angle experiment, induction time measurement, bubble attachment time experiment, Langmuir monolayer, AFM microscope and molecular simulation were performed to investigate the mineralization with ODA collector. The results indicated that the adsorption of ODA collector at the KCl crystal surface was very low. During the flotation process, most of the ODA collector adsorbed at the air bubble surface as precipitation.(3) Selected soluble salts, such as KCl, carnallite and K2SO4, were used as the subjects for the research of flotation theory. Spectroscopy, viscosity and surface tension measurements were performed to study the interaction between salt ion and water molecule. The results show that only water structure breaker salts, such as KCl, could be floated with either anionic or cationic collector, due to the ability to destroy the "ice-like" water structure. On the other hand, the water structure maker salt, such as carnallite, could not be floated with both charged collector, due to the ability to enhance the "ice-like" water structure.(4) Mixed charged collectors and mixed length chain collectors were used to study the flotation behavior of KCl comparing the pure ODA collector. The results indicate that a much higher KCl recovery was obtained when mixed chain length amine was used as collector than mixed charged collector. It is also show, even at low temperature, the flotation recovery of KCl is also satisfied using mixed chain length amine.The results obtained from this study provide a better understanding about the flotation process of soluble salts and also provide theory support for the manipulation and optimization of whole process.