초록 ▼

A method is described for controllably heating an electrolytic cell used for the production of metal, e.g., aluminum, from a compound of the metal, e.g., alumina, to a desired temperature. The method is especially applicable to electrolytic cells which have refractory hard metal articles, e.g., Grou

A method is described for controllably heating an electrolytic cell used for the production of metal, e.g., aluminum, from a compound of the metal, e.g., alumina, to a desired temperature. The method is especially applicable to electrolytic cells which have refractory hard metal articles, e.g., Group 4b metal diboride articles, as internal elements of the cell. The electrolytic cell is brought to the desired temperature, e.g., substantially operating temperature, from ambient temperature by placing a resistance heater having a positive change in resistivity with temperature within the cell and passing current through the heater. Typically, a plurality of heaters is used. In one embodiment, the heaters are placed close to but spaced from the refractory hard metal articles. The heaters are usually connected in parallel to a source of electrical power and in a preferred embodiment are in electrical contact with the cathode and anode of the electrolytic cell. Sufficient current is passed through the resistance heaters to raise the temperature thereof to at least the desired temperature, thereby heating the cell to the desired temperature. The refractory hard metal articles can be part of the electrical circuit.

대표청구항 ▼

A method for controllably heating internal elements of an electrolytic cell for the production of metal to a desired temperature while avoiding objectionable thermal stress in such internal elements, which comprises placing a non-metallic resistance heater having a positive change in resistivity wit

A method for controllably heating internal elements of an electrolytic cell for the production of metal to a desired temperature while avoiding objectionable thermal stress in such internal elements, which comprises placing a non-metallic resistance heater having a positive change in resistivity with temperature within said cell, connecting said heater to a source of electric current, passing sufficient current through the resistance heater to heat said heater to at least said desired electrolytic cell temperature, and continuing to pass current through said heater at least until the internal elements of the cell reach the desired temperature. The method of claim 1 wherein the electrolytic cell is an electrolytic cell for the production of aluminum.