Hydrociclones are used to recoup the sand resulted from the gravel washing or for washing or separatiog different materials, like sand, coal etc. In the interior of the cyclone there is present a centrufugl force, and due to the abrasive materials inside, the wear is very high. Without a proper protection, the life time of a cyclone is very short. The most used material for this application is Remaline 35, wich is soft rubber, just 34 Shore A, very elastic, containing 95% natural rubber. There are cases then the Remaline 35 is nor sufficient and Ceramic lining must be used.