Patent ID: 11944983
Assignee: KAWASAKI JUKOGYO KABUSHIKI KAISHA
Field: Chemical engineering (Chemistry)
Classification: CPC B | IPC B

Claim 0:
1. An electrostatic separator that separates conductive particles from raw materials including the conductive particles and non-charged insulating particles, the electrostatic separator comprising:
a container in which a raw material layer including the raw materials is located;
a lower electrode at a bottom portion of the raw material layer or in the raw material layer;
a fluidization gas supplier configured to supply a fluidization gas that is introduced from a bottom portion of the container into the raw material layer and flows upward in the raw material layer through the lower electrode;
an upper electrode above the raw material layer;
an endless conveyor belt that includes a conveyance surface including a nonconductor and is configured to rotate such that the conveyance surface facing downward passes through a capture region that is above the raw material layer and under the upper electrode;
a power supply configured to apply a voltage between the upper electrode and the lower electrode such that one of the upper electrode and the lower electrode becomes a negative electrode, the other becomes a positive electrode, and an electric field is generated between these electrodes;
a lifter configured to lift or lower the upper electrode; and
lift circuitry configured to monitor a distance between the upper electrode and a surface of the raw material layer and operate the lifter such that the distance between the upper electrode and the surface of the raw material layer falls within a predetermined reference range in which a spark does not occur, wherein:
by bringing the conductive particles and the lower electrode into contact with each other in the raw material layer, only the conductive particles are charged to have polarity that is the same as polarity of the lower electrode;
by dielectric polarization, polarity that is the same as polarity of the upper electrode is generated on the downward-facing conveyance surface of the conveyor belt which passes through the capture region;
the charged conductive particles are selectively separated from the raw material layer by electrostatic force and are made to adhere to the conveyance surface of the conveyor belt; and
the conductive particles are separated and collected from the conveyance surface that has moved to an outside of the electric field.