When clay mineral has been treated by fluoboric acid and mud acid,cation exchgnge capeity (CEC) and exchange hydrogen ion will be decred,and the Spent acid still has some capability to lower CEC.

• 粘土被氟硼酸、土酸处理后，阳离子交换容量（CEC）、交换性氢都将降低，且残余酸液还具有一定的降低CEC的能力。