Device and method for controlling the charging of alumina in a molten-salt electrolysis cell

摘要

The alumina is charged in a controlled manner using known means such as alumina feed pipes, daily storage hoppers, metering devices and/or downcomer pipes, in conjunction with a chisel (30) which can be moved up and down and which keeps at least one crust perforation open. Superimposed on the production current is an alternating current circuit which enables the chisel (30) to be raised immediately by means of an electronic process control system (36) if the chisel enters the electrolyte (14). The alternating current circuit comprises an alternating current source (32), an electronic relay (34) and two capacitors (40). If the alternating current circuit is not closed within a specified time after the chisel (30) has been lowered, the electronic process control system (36) triggers an increase in the pneumatic or hydraulic pressure on the chisel (30). <IMAGE>