Removal of boron from refined brine by using selective ion exchange resins

摘要

Boron removal by ion exchange resin from refined brine which was used to produce low-boron lithium salts was studied. A new boron-specific resin, XSC-800 was used in the experiments for the separation of boron. The column-mode and batch-mode sorption studies were both performed so as to obtain the optimum conditions for boron removal from refined brine. Parameters such as flow rate of brine, boron concentration, temperature, pH, height/diameter (H/D) ratio of the column, anion concentration, stirring speed and diameter of the resin were investigated. The results showed that the removal effect of boron by XSC-800 improved with increasing temperature, pH, H/D ratio, and with decreasing the flow rate of brine, boron concentration, chloride anion concentration and diameter of the resin. While the stirring speed and the recycles of the resin had no significant effects on boron removal. As a result, boron can be removed from refined brine much completely by the resin at the optimum conditions. On the other hand, kinetics of the exchange process was studied by using the moving boundary model. In order to describe the kinetics more accurately, the model was modified by introducing a time correction factor. The results showed that the rate-determining step of this process under the conditions studied was controlled by particle diffusion. In addition, the apparent activation energy E_a of the process was found to be 20.38 kJ/mol.