The decanter centrifuge is used in weighted mud applications to recover valuable weighting material from mud which must be discharged due to unacceptable colloidal solids content. The decanter centrifuge settles out barite and coarse drilled solids which are returned to the active mud system to maintain density. The relatively clean centrate containing liquid and colloidal solids is discarded. These colloidal solids cause many drilling fluid problems, such as high surge/swab pressures and ECD, differential sticking and high chemical costs. Usually the value of the weighting agent in these mud systems makes it economic to recover the weighting agent from the whole mud before it is discarded.Ideally, the barite recovery process should remove only colloidal solids without losing the larger particle sizes used as weighting material.

Discarding potentially reusable barite increases barite use and drilling fluid cost. Barite losses can be reduced when the centrifuge makes the maximum liquid/solids separation. As discussed in the previous section, this means operating the decanter centrifuge at high G-force.