摘要 |
A process for control of the alumina content of the bath in a cell for production of aluminum by electrolysis of alumina dissolved in a molten cryolite-base salt, consisting of alternation of phases of alumina underfeeding and phases of alumina overfeeding compared with a theoretical mean rate of alumina consumption of the cell, the said alternation being a function of values, calculated at the end of each control cycle i of duration T, of the mean resistance R(i) measured at the cell electrode terminals, of the rate of change of this resistance or resistance slope P(i), of the rate of change of the resistance slope or curvature C(i) and of the extrapolated slope PX(i)=P(i)+C(i)xT, these values being compared respectively with reference values Po, Co and PXo in order to modulate, according to an appropriate control algorithm, the alumina content of the bath in a very narrow concentration range between 1.5 and 3.5%.
|