A method of rapidly determining cationic exchange capacity and extractible cations in bentonite is presented in this paper. Separation speed is enhanced by using ammonium chloride-ammonia as exchange agent and replacing centrifugal separation with pumping filtration separation. It is convenient and reliable to determine cationic exchange capacity by replacing nitrogen distillation with calcium chloride-formaldehyde. Precision experiment of the method has been made. All the relative standard deviation are less than 10% while the content of extractible cations kalium,natrium,calcium and magnesium is less than 2 mmol in 100 g bentonite,and all the relative standard deviation is less than 5% while the above mentioned content is more than 2 mmol in 100 g bentonite. With high stability and precision,this method meets the demands of analysis. The relative standard deviation of cationic exchange capacity determination is about 1% and the sum of extractible cations kalium,natrium,calcium and magnesium accounts for 97% of exchange capacity,which satisfies the demands of accuracy.
Bulletin of the Chinese ceramic society