| 主权项 |
1. A method for preparing a mother plate of a permanent cathode to be used in a process for electrolytic recovery of metal, wherein the mother plate of the permanent cathode is in the form of a plate that has two opposite faces and wherein the method comprises steps for
holding the permanent cathode with permanent cathode holders which are attached to a frame means by pressing the permanent cathode between the permanent cathode holders, measuring a shape of the mother plate of the permanent cathode with a mother plate measurement assembly that is attached to the frame means to obtain measurement data, calculating geometric deviation of the mother plate of the permanent cathode in comparison to a predefined reference shape by using said measurement data, using said geometric deviation for automatically controlling a mother plate pressing assembly that is attached to the frame means and that is configured to locally press the mother plate of the permanent cathode for plastically deforming the mother plate of the permanent cathode to at least partly obtain the predetermined reference shape for the mother plate of the permanent cathode, wherein the mother plate measurement assembly that is used in the method comprises several mother plate measurement devices, wherein each of said several mother plate measurement devices being configured to measure a shape of a part of the mother plate of the permanent cathode and wherein each of said several mother plate measurement devices being configured to obtain said measurement data of the shape of the part of the mother plate of the permanent cathode, wherein the mother plate pressing assembly that is used in the method comprises several independently operable mother plate pressing devices each being configured to apply a linear pressing force essentially perpendicularly to one of the faces of the mother plate of the permanent cathode at a location of the mother plate for plastically deforming the mother plate to at least partly obtain the predetermined reference shape for the mother plate of the permanent cathode, wherein the method comprises pressing one of the faces of the mother plate of the permanent cathode with at least one of said several mother plate pressing devices of the mother plate pressing assembly by applying the linear pressing force essentially perpendicularly to one of the faces of the mother plate of the permanent cathode to at least partly obtain the predetermined reference shape for the mother plate of the permanent cathode, wherein the method comprises holding the permanent cathode with the permanent cathode holders during the pressing of the mother plate by means of the mother plate pressing assembly solely at an end of the permanent cathode, which end of the permanent cathode is provided with a hanger bar for supporting the permanent cathode at an electrolytic cell, wherein the method comprises holding the permanent cathode with the permanent cathode holders so that the permanent cathode except for said end of the permanent cathode, which end of the permanent cathode is provided with the hanger bar, is unsupported by the permanent cathode holders during the pressing of the mother plate by means of the mother plate pressing assembly, and wherein the method comprises holding the permanent cathode with the permanent cathode holders both vertically and horizontally in position with respect to said frame means. |
