The thickness of the filter cake (360) can be maintained within a desired range by controlling the slurry velocity and/or the pressure differential across the filter medium (350).

The slurry is filtered and the filter cake is heated to a temperature between about 180 °C and below its melting point for about 12 to about 24 hours.

In a process for mechanically dehumidifying a filter cake, differential pressure causes a treatment fluid to flow through the filter cake.

By the present invention, it is possible to increase the filtering capacity and to reduce the residual moisture of the filtrate cake and the moisture variations in the filtrate cake.

Since the filter cake particles do not invade the well bore, no high pressure spike occurs during the removal of the filter cake.

The present invention relates to a filtration member (1) which is mainly used in a layered filter for forming a filter cake.

The wet filter cake is reslurried in the presence of a dispersing agent.

In the process of the invention, the pigment press cake is first fluidized.

The filter cake is dried through evaporation either to a powder or to a sintered cake of pure polyolefine.

In the process of the invention, the pigment press cake is first fluidized.

External extraction devices enable the filter cake to be withdrawn automatically.

The dispersing agent may be introduced into the wellbore as a component of a filter cake removal treatment fluid or either prior to or after introduction of the filter cake removal treatment fluid.

This imparted motion serves to disengage the cake (42) from the filter cloth (27).

A flaky, or granular filtercake suitable for further processing is obtained.

The nickel precipitate and flocs are preferably then passed through a filter to remove the nickel as filter cake.